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1. STEVENS, A.H.
Improvements relating to the treatment of rubber latex.
B.P. 415, 133; appl. 23.2.33; publ. 23.8.34.
A method of concentrating or creaming rubber latex comprises treating the latex with an organic colloid in the presence of a substance, which is neither alkaline nor acid and is more volatile than water. It has been found that the rate of creaming of latex with gum tragacanth can be greatly accelerated by treating the gum tragacanth with a small amount of certain non-acid, non-alkali, organic liquids before admixture with the latex. Acetone is a suitable substance for this purpose or an aliphatic alcohol such as methyl or ethyl alcohol. The concentrating action starts in approximately one hour as compared with four or more hours for latex treated with gum tragacanth alone. Carrying it out in a centrifuge may accelerate treatment. When the latex is dried the alcohol disappears. 
1937
2. RHODES, E. and SEKARAN, K.C.
Concentration of latex.
B.P. 474, 651; appl. 24.8.36, publ. 4.11.37.
Concentration of latex by creaming is effected by the addition of seed powder obtained from legumes of the tribe Amherstieae or sub-order Caesalpiniea, more especially the tamarind tree (Tamarandus indica). The seeds are roasted until the husks become brittle and easy to remove. After shelling, the seeds are ground and a solution of 3% concentration is prepared by boiling the powder obtained with the appropriate amount of water for one hour. The prepared solution is added to latex in an amount calculated to give 0.3 parts by weight of tamarind seed per 100 parts of the water phase of the latex. It has been found that there is no advantage in using larger amounts of creaming agent and that high ammonia concentrations are not necessary in order to obtain maximum creaming efficiency. After creaming for 48 hours, approximately 16.5 gallons of concentrated latex, having a dry rubber content of 58.3% and an ammonia content of 0.6% were obtained.
3. RHODES, E. and SEKARAN, K.C.
Concentration of latex.
B.P. 476, 073; appl. 1935; publ. 1.12.37.
Latex is creamed by the addition of H2O solution derivatives of a fatty alcohols containing 6-18 carbon atoms per molecule, e.g. the sodium salts of the sulphonated alcohols obtained by the hydrogenation of coconut oil or sulphonated lauryl alcohol.
4. HASTINGS, J.D.
Improvements in and relating to the preparation of softened rubber.
B.P. 531, 723; appl. 31.7.39; publ. 9.1.41.
Peptising agents, (i) toxic kinds such as compounds of phenylhydrazine, and (ii) non-toxic kinds, such as thio-beta-naphtol, napthyl-beta-mercaptan, xylyl mercaptan and the like, are first dispersed or dissolved in a liquid compatible with latex, and then disseminated throughout the latex. The mixture is coagulated, and the heat during drying of the coagulum yields a softened rubber. A suitable emulsion for mixing with latex may also be prepared without a paste mill or homogeniser by using an emulsifiying agent such as that sold under the Registered Trade Mark Agral W.B.S. which is soluble in thio-beta-naphthol. The cost of this emulsion can be still further reduced by dissolving the peptising agent and emulsifying agent in kerosene instead of in a more volatile solvent such as benzene. For use on rubber plantation, only the non-toxic peptising agents are claimed.
5. WENTWORTH, V.H.
Improvements in and relating to the preparation of softened rubber.
B.P. 535, 837; appl. 1.12.39; publ. 23.4.1941.
Softened rubber is produced by adding to the latex an emulsion of an organic peroxide of the general formula R1 - CO - O - O- CO- R2, where Rl and R2 are aliphatic or aromatic radicals, and then coagulating the latex and simultaneously breaking down the emulsion so that the peroxide is deposited in the coagulum. Benzoyl peroxide is a suitable substance to add to the latex, data showing the effect of the addition of various proportions of the peroxide on the plasticity of the rubber being given. The softness of the rubber is markedly dependent on the conditions of drying in the initial stages. When drying normal sheet rubber, smoke-drying produces a softer sheet than air-drying, but the reverse is the case when benzoyl peroxide is present. Data illustrating this point are given. It is therefore recommended that if it is desired to prepare smoked sheet and also to secure the utmost softening from a given amount of benzoyl peroxide, the sheets should be submitted to an initial drying period in hot air at 120°F, free from smoke, followed by the required amount of smoking.
6. WENTWORTH, V.H.
Improvements in and relating to the preparation of softened rubber.
B.P. 536, 301; appl. 1.12.39; publ. 9.5.41.
Peptising agents which are insoluble in water, but posseses an acidic grouping capable of reacting with an alkali to form a soluble salt, are added to latex as a solution in an alkaline medium. Coagulation of the latex by addition of an acid then simultaneously precipitates the peptising agents in intimate contact with the coagulated rubber. As acidic peptising agents reference is made to compounds containing carboxy, phenolic and mercapto groups. In an example, mercaptobenzthiazole 140, dissolved in 312 cc. of 2.89 N caustic soda solution, and diluted to 7000 cc. with water was added to latex of 15.63% dry rubber content in the proportion of 170 cc. per gallon. The rubber obtained from this latex had a plasticity of 0.63 when dried in air at 140°C, and of 0.80 in a 'tunnel' smoke-house. The corresponding figures without the mercaptobenzthiazole addition were 1.52 and 1.33, respectively.
1943
7. WENTWORTH, V.H.
Improvements in the preparation of purified latex and the preparation of rubber therefrom.
B.P. 551, 666; appl. 26.8.41; publ. 4.3.43.
The invention relates to the treatment of latex and the preparation of a purified rubber having a reduced content of nitrogen and an improved resistance of absorption of water as compared with the normal plantation product. The invention comprehends both the method of treatment and the product obtained.
8. PHILPOTT, M.W.
Improvements in the manufacture of rubber.
B.P. 681, 486; appl. 13.6.60; publ. 22.10.52.
To prevent yellow colouration in the preparation of crepe rubber, even when prepared from latex from Prang Besar 186 or 25 clones, the treatment includes the addition to the latex of aryl or alkyl mercaptans, or substances releasing their active radicals, in proportions not exceeding 0.1% by weight calculated on the rubber, this being insufficient to effect appreciable softening of the rubber, but effective to bleach the resulting product. In an example, 501 of clone Prang Besar 186 latex is diluted to 20% rubber content, mixed with a solution of 50g. sodium bisulphite, and an emulsion of 5 g xylyl mercaptan of zinc betanaphtyl mercaptide, and then coagulated with 40 g of formic acid in 8.1 or water.
9. PHILPOTT, M.W. and WALKER, A.
Improvements in the drying of natural rubber coagulum.
B.P. 726, 181; appl. 1.4.49; publ. 16.3.55.
The process of drying NR coagulum is considerably accelerated, and if desired, higher temperatures can be employed without causing blistering, by adding to the latex prior to coagulation formaldehyde, salts of heavy metals such as lead, chromium, and zinc, and urea or vegetable or synthetic tanning agents. In comparison with a drying time of 8 days for untreated coagulum, coagulum treated with 0. 28% (on the dry rubber) of zinc sulphate dried in 5 days, with formaldehyde 0.18% in 2 days, and with formaldehyde 0.1% with zinc sulphate 0.1% in 3 days. The effect is believed to be due to a modification of the protein structure in the body of the drying rubber.
10. BAPTIST, E.D.C. and DE JONGE, P.
Improvements in systemic herbicide compositions.
B.P. 803, 772; appl. 3.8.54; publ. 29.10.58.
The invention relates to compositions suitable for the treatment of rubber bearing Hevea for the purpose of stimulation of yield and/or bark renewal. The invention provides improved compositions suitable for treating Hevea for the stimulation of yield and/or bark renewal and not capable for forming stable dispersions in aqueous media including a lower alkyl ester of 2,4,5-trichlorophenoxyacetic acid in which the alkyl group contains up to five carbon atoms dissolved in vegetable oil of a mixture of vegetable oil and mineral grease.
11. COOK, G.S. and SMEE, A.T.
Improvements in and relating to soil stabilisation.
B.P. 803, 012; appl. 8.11.54; publ. 15.10.58.
This invention relates to the stabilisation of soil for the construction of foundations for roads, footpaths, runways or the like, wherein unvulcanised rubber natural or synthetic rubber latex, with or without an appropriate binder which is not a vulcanising or a swelling agent, is mixed into the soil. Cement is also added. The advantages of using the invention are that unvulcanised rubber latex possesses marked characteristics of flexibility, pliability, tenacity, adhesion and resistance to temperature susceptibility, without the disadvantage of rigidity and liability to cracking as shown in normal soil/cement stabilised foundation or surfacing.
12. PHILPOTT, M.W.
Improvements in and relating to the preparation of natural rubber.
B.P. 803, 013; appl. 20.3.55; publ. 15.10.58.
This invention provides a method whereby a novel type of raw natural rubber is prepared which differs from ordinary natural rubber in that it has less tendency to swell at the calender nip or extruder die even when it is uncompounded or only lightly compounded with fillers and plasticisers. It also calenders, extrudes and otherwise moulds with a remarkably smooth surface after only a short period of mastication. It provides a method of preparing raw natural rubber in crepe or sheet form by coagulating natural rubber latex which has been mixed with latex that has been subjected to vulcanising ingredients which have been removed by centrifuging.
13. SEKAR, K.C.
Improvements in the preservation of latex.
B.P. 821, 872; appl. 19.12.56; publ.14.10.59.
Hevea latex concentrate containing less than 0.5% and more than 0.15% ammonia is preserved by the addition of a selenium alkyl dithiocarbamate (e.g. selenium diethyl dithiocarbamate). Between 0.01% and 0.1% of a surfactant (e.g. ammonium laurate) also may be added.
14. TAYSUM, D.H.
Improvements in the preservation of latex.
B.P. 811, 942; appl. 16.12.55; publ. 15.4.59.
It has been found that a considerable number of bacteria survive the usual methods of preserving latex, for example by the addition of ammonia. The invention claims the use of small proportions of a sulphonamide. These compounds are stable in an alkaline medium and can be mixed to give solutions which are micro-organisms. The sulphonamide may be sprayed on the tapping cut, or added to the collecting up or to latex already containing ammonia. The concentrations should exceed 0.001%. Sulphanilamide, sulphapyridine, sulphatiazole, sulphadiazine, and sulphamerazine are amongst the suitable products listed.
15. EDMONSON, H.M.
Preparation of composition of natural rubber.
B.P. 836, 393; appl. 14.4.55; publ. 1.6.60
This invention relates to the preparation of compositions of natural rubber with reinforcing materials. One method of incorporating such reinforcing materials into rubber is to mix a dispersion or solution of the reinforcing material with latex and to coprecipitate the mixture by addition of acid or other precipitating agent. When large quantities of reinforcing fillers are added to latex, the mixture upon acidification does not form a continuous coagulum but a flocculated precipitate which is impossible to sheet on a crepeing small mill in the normal way. This can be avoided by application of heat at controlled temperatures to the mixture and/or the acid coagulant and also during milling. Fillers, which can be incorporated in this way, are lignin, carbon black, silica, silicates, clays and synthetic resins, e.g. polystyrene.
16. LOWE, J.S. and TAYSUM, D.H.
Improvements in the preservation of latex.
B.P. 839; 758; appl. 18.8.55; publ. 29.6.60.
This invention relates to the preservation of latex and latex concentrates by the addition of antibiotics. Known latex preservatives permit the survival of bacteria. Antibiotics, e.g. penicillin, streptomycin, oxytetracycline, chlortetracycline and chloramphenicol, are claimed as preservatives for natural rubber latex and these can be sprayed on the tapping panel, poured into the tapping cup, or added to the latex at the collecting station. The latex is then concentrated and a detergent, which may or may not be bactericidal, or stabilising soap is added to increase its mechanical stability.
17. SEKAR, K.C. and MORRIS, J.E.
Improvements in the preservation of natural rubber latex.
B.P. 852, 280; appl. 15.11.55; publ. 16.10.60.
The invention relates to the preservation of natural rubber latex, both on short or long term basis. On a short-term basis, anti-coagulants are added to the latex prior to the making of sheet and crepe, and temporary preservatives are added to it prior to the preparation of concentrate. On a long-term basis, it is for the preservation of latex concentrates during shipment and storage prior to use. The temporary preservation of fresh latex is of importance in avoiding blemishes in sheet rubber produced from the latex, particularly bubbles and dark colourations. The additives of this specification, ammonia and boric acid are superior to formaldehyde and ammonia in that a sheet of light colour is produced.
18. SEKAR, K.C. and MORRIS, J.E.
Process of preserving freshly harvested rubber latex.
U.S.P. 2, 932, 678; appl. 5.11.56; publ. 12.4.1960.
The invention relates to the preservation of natural rubber latex obtained from Hevea brasiliensis, both on a short term basis for fresh latex, including anticoagulants added to the latex prior to the making of sheet and crepe, temporary preservatives added to latex prior to the preparation of concentrates, and on a long term basis for the preservation of latex concentrates during shipment and storage prior to use. It is desirable in carrying out the preservation treatment to add the ammonia and boric acid anticoagulant (also referred to as ammonium borate) as soon as possible after tapping although appreciable improvements of the product are effected if the anticoagulant is added at any time before acid coagulation.
19. SOUTHORN, W.A.
Methods and apparatus for measuring gel strength and viscosity.
B.P. 842, 977; appl 14.6.56; publ. 4.8.60.
The strength of weak gels, such as latex coagulum, is measured by applying a small cyclic torsional stress, through the use of rotating stainless steel bob. This is done in one direction then in the reverse direction, and recording the stress required to produce the constant rnaximum strain at the end of each cycle. The strain is below the yield value of the material and applied slowly so as to discriminate between viscosity and structural effects.
20. SEKHAR, B.C.
Improvements in and relating to the preparation of rubber.
B.P. 869, 283; appl. 30.7.57; publ 31.5.61.
Ageing characteristics of natural or synthetic polyisoprene elastomers are improved by adding to the latex of the raw polymer reducing agents, including polyalkyline polyamines, e.g. diethylene triamine, triethylene tetra-amines or tetra-ethylene pentamine; alkali metal sulphites or bisulphites; or aromatic amines such as benzidine or phenylene diamine. A chelating agent such as ethylene diamine tetra-acetic acid or one of its salts may also be added to chelate heavy metal ions which catalyse the decomposition of rubber peroxides.
21. SEKAR, K.C. and WREN, W.G.
Improvements in the inhibition of volatile acid formation in preserved latex.
B.P. 861, 940; appl. 19.12.56; publ. 1.3.61.
The formation of volatile fatty acids is inhibited by adding, before or immediately after concentration, an enzyme poison, especially not more than 0.2% of zinc oxide, in addition to any bactericide. Coagulation of the latex is thus avoided.
22. SEKHAR, B.C. and WREN, W.G.
Preparation of superior processing rubbers.
B.P. 880, 739; appl. 28.3.57; publ. 25.10.61.
Superior processing characteristics can be imparted to a wide range of SR and NR including lower grades of NR by blending them in suitable proportions with a masterbatch. The masterbatch contains a high proportion of vulcanised rubber particles (preferably 80% or 90%) embedded in a matrix of unvulcanised latex with field latex followed by coagulation. The masterbatch will readily blend with raw rubber to give mixtures containing the required proportion of vulcanised particles, usually 20%, to produce a superior-processing product. Both wet and dry mixing processes are claimed. In an example, a rubber made by this method gave an extrusion swell of 18.7% when it was made into a tyre tread compound, compared to a value of 32.5% for the remilled crepe control.
23. WREN, W.G.
Concentrated latex. B.P. 875, 530; appl. 30.7.57; publ. 23.8.61.
Hevea latex, concentrated and preserved by the usual means is relatively unstable when first prepared but usually 'matures' during shipment, acquiring a degree of stability acceptable to the user. Latex from some of the newer clones, however, is extremely slow to mature, and moreover, has a lower degree of stability after maturation. Mild oxidation accelerates maturation but the rubber is thereby rendered softer and more susceptible to ageing. The present invention contemplates the usual maturation by mild oxidation but prevents degradation of the rubber by the addition, preferably before aeration, of polyfunctional amines as disclosed in B.P. 869, 283. These interact with peroxide groups and include such amines as benzidine, phenylene diamines, or polyalkylene polyamines such as tetraethylene pentamine; sequestrants such as ethylene diamine tetra-acetic acid also may be used.
24. GRAHAM, D.J. and TAYSUM, D.H.
Preservation of rubber latex.
B.P. 908, 283; appl. 24.7.58; publ. 17.10.62.
The latex is preserved by the addition of at least 0.001% w/w of a thiobi-halophenol, particularly 2,2'-thiobis-(4, 6 dichlorophenol), added in the form of an emulsion or dispersion of (preferably) as an alkali metal or ammonium salt. The compounds have outstanding anticoagulation, and preservative activity and are free from discolouration.
25. TAYSUM, D.H.
Production of latex.
B.P. 886, 341; appl. 8.2.57; publ. 3.1.62.
Bacteria are prevented from entering latex while it is still in the tree and during emergence, with the resulting production of very white concentrated latex of very low volatile fatty acid content, of sheet rubber free from fermentation bubbles, and of very pale crepe rubber. Methods of protection against infection include application of alkaline detergent bactericidal and/or bacteriostatic dressings to the tree around the region of tapping, in conjunction with antibiotic injection. Also removal of a section slightly deeper than usual (1/5 in. instead of 1/20 to 1/30 in.) will remove all previously contaminated latex vessels and the subsequent maintenance of aseptic conditions will prevent reinfection.
26. TAYSUM, D.H.
Production of rubber latex. B.P. 892, 311; appl. 27.6.57; publ. 28.3.62.
A liquid bactericidal dressing of a given composition is painted round the tapping cut on the tree and is effective for several months in giving increased yields of improved quality latex, e.g. very white concentrated latex of low initial volatile fatty acid content. This gives sheet rubber tree from fermentation bubbles or very pale crepe rubber. The method is slightly less effective than the antibiotic injection method claimed in B. P. 886, 341 but can be easily carried out by unskilled workers.
27. SEKHAR, B.C. and SHIPLEY, F.W.
Rubber derivatives.
B.P. 939, 350; appl. 14.2.61; publ. 16.10.63.
Improved durability and crystallisation resistance are obtained by treating rubber with a thiol compound. It is now found that natural latex contains an inhibitor which is removed by adding formaldehyde and allowing to stand 24 hours and preferably 48 hours before reacting with the thiol. Intermediate stages of dilution and stabilisation may be included in the process.
28. TAYSUM, D.H.
Improvements in or relating to the preservation of rubber latices.
B.P. 926, 162; appl. 23.1.61; publ. 15.5.63.
Small quantities of ethylene oxide (of the order of 0.1% to 1 %) can be used to preserve field latex and latex concentrates for periods of several days. The preservative causes no pH changes in the latices, is suitable for use with latices used to make pale sheet and crepe rubber, and requires no modification of normal manufacturing processes.
29. SEKHAR, B.C.
Stabilisation of natural rubber.
B.P. 965, 757; appl. 29.2.60; publ. 6.9.64.
This invention is for improvements in or relating to the stabilisation of natural rubber and is concerned with the treatment of rubber latex to produce a rubber which has improved storage properties. Research has indicated that the hardening of unvulcanised NR during storage results from crosslinking via oxygenated functional groups, such as carbonyl or carboxyl. By adding a reactive derivative of ammonia, of the general formula XNH2, where X is a hydroxy or hydroxyalkyl group, or aromatic nucleus free from any basic group or basic substituent. The above mentioned ammonia derivative added to the latex is preferably between 0.1% and 5% by weight of the rubber solids in the latex. In examples, hydroxylamine, naphthylamine, and ethanolamine were used.
30. SEKHAR, B.C. and NIELSEN, P.S.
Preparation and processing of natural and synthetic rubbers.
B.P. 960, 880; appl. 28.9.60; publ. 17.6.64.
A dry rubber having superior processing properties is made by blending a casein-rubber masterbatch, comprising a NR or SR having casein dispersed therein in an amount of between 20% and 80% by weight of the resultant rnasterbatch, into a dry NR or SR in an amount such as to provide a blend containing 10% to 20% of casein by weight of the final blend. SBR or neoprene may be used. The improvement includes a reduction in extrusion swell an increase in extrusion rate.
31. SEKHAR, B.C. and NIELSEN, P. S.
Preparation and processing natural and synthetic rubbers.
B.P. 960, 881; appl. 28.9.60; publ. 17.6.64.
A masterbatch is made by admixing an aqeous solution of polyvinyl alcohol with a rubber latex co-precipitating the two by coagulating the latex. Also claimed is a method of producing a dry rubber blend having superior processing properties by blending the masterbatch into a dry NR or SR in an amount such as to provide a blend containing 10% to 20% of polyvinyl alcohol by weight of the final blend. A reduction in extrusion swell and an increase in extrusion rate is achieved by using the resulting blend.
32. WREN, W.G.
Improvements in or relating to the preservation of rubber latex.
B.P. 949, 364; appl. 23.6.59; publ 12.2.64.
A process for the preservation of field latex (or a concentrate) by adding to it 0.05% to 0.002% of 8-hydroxyquinoline, 0.1% to 0.3% of ammonia, and 0.5% to 0.1% of boric acid and/or 0.1% to 0.01% of zinc oxide, by weight of the latex is claimed. This invention is particularly applicable to the treatment of concentrated latex which may be produced by centrifuging with or without chemical creaming.
33. SEKHAR, B.C.
Production of modified rubbers.
B.P. 980, 258; appl. 8.9.60; publ. 13.1.65.
This invention relates to the production of modified rubbers of the kind known as graft polymers. It comprises successively polymerising a plurality of separately added increments of a vinyl or vinylidene monomer or monomers in a natural or synthetic rubber, using an organic peroxide or hydroperoxide as the polymerisation initiator. The vinyl or vinylidene monomer or monomers being polymerisable in the presence of the latex and each of the increment is being substantially completely polymerised before the next increment is added. The use of methyl methacrylate as the vinyl monomer is described in the examples.
34. SEKHAR, B.C.
Oil-extended rubber compositions.
B.P. 1, 000, 588; appl. 2.7.63; publ. 4.8.65.
This invention includes a process for the production of an oil/rubber masterbatch which comprises emulsifying a rubber extender oil in a latex of vulcanised natural or synthetic rubber having a combined sulphur content of 1% to 2.5% by weight of the latex solids, co-precipitating the latex and emulsified oil in the form of a crumb and separating the crumb from the aqueous reside. The precipitated crumb is usually washed and dried. Because of the vulcanised particulate structure of the latex, the oil extended crumb presents no difficulty in drying. The co-precipitation of the latex and emulsified oils is usually effected by coagulation of the mixed emulsion, by the addition of an acid, such as formic acid.
35. SEKHAR, B.C. and ANGOVE, S.N.
Hydrazine-formaldehyde as a reinforcing agent for rubber latex foam.
U.S.P. 3, 215, 651; appl. 25.8.61; publ. 2.11.65.
This invention is for improvements in or relating to the reinforcement of rubber and is directed to the reinforcement of natural and synthetic rubbers in latex form. It comprises reacting hydrazine with formaldehyde in situ in the latex. The process of the invention results in the production of a hydrazine formaldehyde resin intimately associated with the dispersed polymers of the latex. The resin effects a reinforcement of the latex which makes it possible to produce foam rubbers of enhanced compression modulus and films of increased modulus and strength from Hevea latex concentrate. The effect obtainable with latices made from synthetic elastomers is less marked than with natural rubber latex which may be treated in its various conventional forms, e.g. field latex, concentrated latex and latices containing preservatives such as ammonia.
36. BRENT, M.
Improvements in or relating to the preservation of natural rubber latex.
B.P. 1, 017, 532; appl. 20.6.61; publ. 19.1.66.
The present invention provides a method of preserving the latex until it is made into crepe or sheets and to effect a stabilisation of the hardness of the resulting rubber. Such rubbers, apart from being free of blemishes and bubbles, have the advantage that they do not undergo significant changes in hardness on storage and is based upon the discovery that hydrazine is an effective preservative and crosslinking agent for rubber. The addition of hydrazine to latex for the purpose of preserving it, or as an anticoagulant, can be conveniently made to field latex either in the cup in which it is collected in or to the field latex in the collecting vessels or bulking tanks.
37. SEKHAR, B.C. and ANGROVE, S.N.
Reinforcement of rubber.
B.P. 1, 015, 603; appl. 25.8.61; publ. 5.1.66.
A process for the reinforcement of natural and synthetic rubber latices comprises reacting hydrazine with formaldehyde in situ in the latex. Also claims articles formed by foaming such a resin-containing rubber latex, and articles formed by dipping a form into resin containing rubber latex. The application of this process to natural rubber and styrene/ butadiene copolymer is described.
38. TAYSUM, D.H. and McDONNELL, J.J.
Reduction of bacterial infection in latex.
B.P. 1, 015, 591; appl 26.1.62; publ. 5.1.66.
A method of preventing and/or reducing bacterial infection in the tapping of a rubber tree and in the latex by forming an air-tight enclosed space surrounding the tapping panel on the tree. This is done by sealing a gas-impermeable sheet of material, e.g. polyethylene, around that part of the trunk containing the tapping panel, to leave an enclosed air space sealed from the atmosphere, creating a non-coagulating bactericidal atmosphere within the enclosed space prior to the tapping operation, tapping the tree, and collecting the latex between the enclosed space. The bactericidal atmosphere is preferably created at least 12 hours before tapping and can be produced by the introduction of ammonia or formaldehyde into the enclosed air space.
39. COCKBAIN, E.G. and GREGORY, J.
Improvements in or relating to the treatment of natural rubber latex.
B.P. 1, 060, 353; appl. 27.1.65; publ. 1.3.67.
A stabilised natural rubber latex concentrate which may be produced by centrifuging, creaming or evaporation, which concentrate contains from 0.2% to 0.8% by weight of ammonia, from 0.02% to 0.2% by weight of a fatty acid soap and from 0.1% to 2.0% by weight of an inorganic sodium or potassium salt and/or from 0.02% to 0.3% by weight of a mono-or chlorophenol or of a nuclear alkyl substitution derivative. The said chlorophenols may be used as such or in the form of the sodium, potassium or ammonium salts.
40. SEKHAR,
B.C.
Processing improvements to synthetic rubbers.
B.P. 1, 075, 400; appl. 13.8.63; publ. 9.8.67.
Synthetic rubber is given improved processing properties by mixing synthetic rubber latex which has been vulcanised to a sulphur content of 1% to 2.5% by weight of the latex solids, with an unvulcanised, sulphur-vulcanisable synthetic and/or natural rubber latex to give a latex mixture containing 15% to 20% by weight of vulcanised rubber based on the solids content. It is then coagulated, preferably with formic acid. The vulcanised synthetic rubber latex may in part be replaced by a vulcanised natural rubber latex. When the mixture of latices contains more than 50% of the vulcanised component it is suitable for use as a masterbatch.
41. SEKHAR, B.C. and CHIN P.S.
Improvements in or relating to the processing of natural rubber.
B.P. 1, 075, 234; appl. 5.5.64; publ. 12.7.67.
Rubber in crumbled form is obtained by milling a masterbatch comprising a wet coagulum of natural or synthetic rubber latex having compatible oil dispersed with wet NR in the form of a coagulum or solid mass. The masterbatch is suitably prepared by emulsifying or dispersing the oil in the latex and coagulating the resultant mix. The latex is suitably vulcanised latex or a mixture of vulcanised and unvulcanised latices. Tbe masterbatch may contain up to 90 wt. % of the oil. The amount of the masterbatch used is preferably such that the crumbled rubber contains 3 to 10 wt. % of the oil.
42. SEKHAR, B.C. and CHIN P.S.
Improvements in or relating to the processing of natural rubber.
B.P. 1, 075, 235; appl. 13.5.64; pub. 12.7.67.
Rubber in crumbled form is produced by milling an incompatible oil and wet natural rubber in the form of a latex coagulating or solid mass. The crumbled rubber does not knit back to a crepe even on repeated milling or on standing. The mixture of the oil and rubber is suitably obtained by mixing the oil in the form of an aqueous emulsion or dispersion with natural rubber latex and then coagulating the mixture. The oil is suitably castor oil or silicone grease and is incorporated into the rubber in an amount of 0.25% to 2% by weight of the rubber.
43. COCKBAIN, E.G., GREGORY, J. and PILLAI, N.M.
Improvements in or relating to the treatment of rubber latex.
B.P. 1, 105, 086; appl. 19.11.65; publ. 6.3.68.
Ammonia-preserved NR latices (including concentrates) and synthetic cis-polyisoprene latices are stabilised against free-thaw coagulation by the addition of a small amount of a salt of salicylic acid. Suitable salts are the sodium, potassium, ammonium and triethanolamine salts. The latices may also contain secondary preservatives and surface active agents.
44. SEKHAR, B.C.
Improvements in or relating to the preparation of lower grade natural rubbers and skim rubbers.
B.P. 1, 122, 463; appl. 16.11.65; publ. 7.8.68.
A method of improving the raw ageing characteristics of lower grade rubbers and skim rubbers by coagulating it with an aqueous solution of oxalic acid is described. The oxalic acid is employed in an amount from 0.01% to 1.0% of the solid oxalic acid based on dry rubber content by weight of the rubber undergoing treatment. The rubbers may be in finely divided form, i.e. in the form of latex or in dry comminuted form.
45. SHIPLEY, F.W.
Improvements in or relating to the production of rubber compositions.
B.P. 1, 125, 801; appl. 5.2.65; publ. 5.9.65.
A NR/carbon black masterbatch is produced directly from a natural rubber field latex. An aqueous dispersion of carbon black stabilised with a dispersing agent is added to the latex, optionally preserved with up to 0.2 wt. % ammonia. The mixture is agitated to effect uniform mixing and is further agitated until the rubber flocculates and finally coagulates. The coagulum is then separated from the serum. The carbon black may be used in amounts of up to 100 wt.% of the rubber in the latex. If desired, an aqueous emulsion of mineral oil is intimately mixed with the latex prior to the addition of the black.
46. SMITH, J.F.
Improvements in or relating to coagulation of latex.
B.P. 1, 106, 430; appl. 21.12.65; publ. 20.3.68.
The present invention relates to a process for the coagulation of natural rubber latex, which comprises adding to fresh rubber latex an amount of phosphoric acid sufficient to reduce the pH of the latex at least to the coagulation point. The latex may contain an amount of ammonia sufficient to preserve it from substantial biological spoilage. The amounts of phosphoric acid added are to produce a pH value in the range of 6 to 3 in the latex depending on the vulcanising characteristics required of the rubber in accordance with existing practice. The use of phosphoric acid in place of formic or acetic acid results in dramatic reduction in the iron pick-up from the creping rollers by approximately an order in magnitude with a consequent improvement in the colour of the sheet rubber. The reduction of iron contamination in the latex is accompanied by a dramatic reduction in the corrosive rusting of the creping rollers.
47. SMITH, J.F. and SEKHAR, B.C.
Improvements in or relating to the preparation of lower grade natural rubbers and skim rubbers.
B.P. 1, 131, 706; appl. 31.3.66; publ. 23.10.68.
Lower-grade rubbers, e.g. cup lump and trace lace in the form of crumbs or crepe, are treated to improve their raw ageing properties, by soaking in an aqueous phosphoric acid solution.
48. JOHN, C.K., NEWSAM, A. and GOMEZ, J.B.
Improvements in or relating to the processing of Hevea latex.
B.P. 1, 203, 110; appl. 9.5.68; publ. 26.8.70.
This invention provides a method of coagulating Hevea latex as obtained from the tree or in a diluted form. It comprises mixing with the latex at a pH not above 8; (I) an anionic surfactant whose anion has the general formula:
CH2 - COOR
|
CH2 - COOR
|
SO3
CH2 - COOR
|
CH2 - COOR
|
SO3
where R is an alkyl group, and (II) a salt of an alkaline earth metal (calcium, strontium or barium). R in the first additive is preferably an alkyl group of the type CnH(2n+1) and particularly where the alkyl groups is a branched chain and n is from 4-9, the coagulating efficiency then increasing with chain length. Particularly preferred additives are dioctyl sodium sulphosuccinate or dinonyl sodium sulphosuccinate. In general, the solvent used affects coagulating efficiency.
49. JOHN, C.K., NEWSAM, A. and SEKHAR, B.C.
Improvements in or relating to the coagulation of natural latex with anionic surfactants.
B.P. 1, 192, 407; appl. 6.12.67; pub. 20.5.70.
This invention describes a simple and economic method of precipitating rubber from latex by an alternative path that does not involve the precipitation of serum protein at the same time. It provides a method of coagulating
CH2 - COOR
|
CH2 - COOR
|
SO3
Hevea latex, which comprises adding an anionic surfactant having an anion of the general formula :
CH2 - COOR
|
CH2 - COOR
|
SO3
where R is a saturated alkyl group, in an amount to coagulate the latex. A dialkyl sulphosuccinate is used as surfactant.
50. RITCHIE, A.H. (KUALA LUMPUR-KEPONG AMALGAMATED LTD)
A method of extending a natural rubber with an oil.
B.P. 1, 211, 842; appl. 25.8.66; publ. 11.11.70
A method of extending a natural rubber with oil is described. The method comprises by comminuting and drying a natural coagulum and bringing the formed loose aggregate of rubber particles into intimate contact with the compatible oil. The proportion of oil and the period of contact being such as to bring about the desired degree of extension. After extension, the rubber may be pressed to a solid block for transportation. The method was carried out at a temperature of from 50°C to 100°C.
51. SOUTHORN, W.A.
Method and apparatus for applying a gas or vapour to a tree.
B.P. 1, 192, 528; appl 14.11.68; publ. 20.5.70.
A flexible frame, e.g. of expanded polystyrene, is stuck to the trunk of the tree, e.g. by natural rubber latex and a container for holding gas or vapour-generating substance(s) is secured to the container in such a way that its interior is in communication with the trunk. The gas generating substances may be chloroform, or calcium a carbide which generates acetylene by reaction with moisture from the tree. The application of e.g. acetylene, chloroform or ethylene oxide to the bark of Hevea brasiliensis trees results in substantial increase in the yield of latex.
52. PAKIANATHAN, S.W.
Stimulation of rubber yield in Hevea brasiliensis. B.P. 1, 255, 991; appl. 18.2.69; publ. 8.12.71.
A method of treating rubber-bearing Hevea brasiliensis for the purpose of stimulation of yield by applying a halogenoparaffin, other than chloroform. The halogenoparaffin is a liquid and is applied in admixture with grease as a carrier to the bark below the tapping cut. The halogenoparaffin is l-bromopentane or l-bromododecane and the grease is palm oil.
53. SMITH, J.F.
Improvements in the compounding of elastomers.
B.P. 1, 255, 354; appl. 7.1.69; publ. 1.12.71.
This invention provides a method of preparing a vulcanisable dry rubber composition from rubber latex. It comprises dispersing in the latex the desired vulcanising ingredients in proportions to vulcanise the rubber in the latex to the desired extent, coagulating the latex in the mixture thus produced, washing the coagulum, drying the washed coagulum and homogenising the dried coagulum again under conditions such that curing does not take place. The resulting vulcanisable dry rubber composition can be processed and cured by means of conventional dry rubber processing methods and equipment. It can be moulded to give shaped articles and may be used as springs and in other engineering applications.
54. ABDUL WAHAB BIN ABDULLAH
Improvements in the extraction of rubber latex from Hevea brasiliensis.
B.P. 1, 293, 934; appl. 17.6.69; publ. 25.10.72.
This invention relates to a method of extracting rubber latex from rubber bearing Hevea brasiliensis in which low intensity tapping systems are used in conjunction with chemical treatments to enhance latex flow. The chemical treatment is by the application on n-butyl ester 2,4, 5-trichlorophenoxy acetic acid.
55. ABRAHAM, P.D., GOMEZ, J.B., SOUTHORN, W.A. and WYCHERLEY, P.R.
A method of stimulation of rubber yield in Hevea brasiliensis.
B.P. 1,281, 524; appl. 22.10.68; publ. 12.7.72.
This invention relates to the treatment of rubber-bearing Hevea brasiliensis. It provides a method of treating rubber-bearing Hevea brasiliensis for the purpose of stimulation of yield of rubber latex. The method includes applying a substance, other than a substance in the given list, which causes ethylene to be provided in or in close proximity to the latex-bearing tissues of the tree.
56. JOHN, C.K. and NEWSAM, A.
A continuous latex preservation.
B.P. 1, 293, 176; appl. 4.12.69; publ. 18.10.72.
The invention provides a method of preserving field latex of Hevea, either diluted or undiluted, from coagulation. The method involves maintaining the pH of the latex at a value of at least one addition of urea or by making at least one addition of a nitrogenous base and at least one addition of urea. The nitrogenous base may be ammonia or an organic amine. Therefore, the pH of the field latex may be raised from its natural level (about 6.5) to 9.0 by the addition of a solution of ammonia and continuously maintained at this level by further additions of ammonia as required. It is found that after a few days a stage is reached when no further additions are required. The latex can be kept fluid indefinitely, with no further additions or only minor and infrequent further additions of ammonia.
57. PAKIANATHAN, S.W.
Treatment of Hevea brasiliensis.
B.P. 1, 296, 715; appl. 9.7.70; publ. 15.11.72.
This invention relates to the treatment of rubber-bearing Hevea brasiliensis for the purpose of stimulation of yield by the agency of ethylene. The method comprises generating the ethylene in situ by chemical reaction between at least two reactants. Preferably the ethylene is generated in situ between an ethylene-l, 2- dihalide, particularly ethylene-1, 2-dibromide, and metallic zinc, e.g., in granulated form, or an alkali metal iodide, e.g. sodium iodide preferably in the presence of an alcohol, e.g. ethanol. By the use of this reaction, a controlled and sustained supply of ethylene can be achieved over a period of weeks without the use of expensive chemicals. Five examples illustrating the invention are also included.
58. CAIN, M.E., KNIGHT, G.T., GAZELEY, K.F. and LEWIS, P.M.
Improvements in or relating to the treatment of rubber.
B.P. 1, 340, 673; appl. 4.5.70; publ. 12.12.73.
A process for improving the resistance to degradation of natural rubber or of a synthetic rubber having an unsaturated carbon chain is claimed. The dry rubber was reacted with a nitrosophenol or an ether or a nitrosoaniline so as to form rubber-bound groups having antioxidant properties. The reaction is performed in the presence of a salt of a thiol, which improves the resistance to oxidative degradation conferred by the rubber-bound antioxidant.
59. DICKENSON, P B.
Compositions containing plant growth regulants.
B.P. 1, 315, 131; appl. 11.3.70; publ. 26.4.73.
A composition for use in plant growth regulation particularly for stimulating yield of rubber latex for Hevea brasiliensis comprises (a) a volatile or gaseous plant growth regulant e.g. ethylene, propylene acetylene and (b) a solid non-volatile adsorbent material, e.g. activated charcoal silica gel dispersed in (c) a viscous fluid medium e.g. animal, vegetable or mineral fats or oils or waxes, polyethylene oxide, gelatine and natural rubber coagulum.
60. GORTON, A.D.T.
Treatment of fresh natural rubber latex.
B.P. 1, 303, 044; appl. 17.9.69; publ. 17.1.73.
The present invention provides a method by which natural rubber latex concentrate can be chemically treated to produce latex suitable for foam manufacture but having reduced volume shrinkage in the final article resembling more closely synthetic latex. This enables a manufacturer to increase the proportion of natural rubber latex in the blend of latices used, or possibly to replace synthetic latex by natural rubber latex without altering his mould or product size.
61. GORTON, A.D.T.
Treatment of rubber latex.
B.P. 1, 303, 045; appl. 17.9.69; publ. 17.1.73.
The invention provides a process for treating rubber latex to increase the modulus of a vulcanisate. The process comprises forming a mixture of a natural rubber latex concentrate or of a mixture of a natural rubber latex concentrate and a synthetic rubber latex, with from 0. 5% to 4% by weight on the dry rubber content of the latex concentrate or mixture of a sodium, potassium or ammonia salt of a saturated fatty acid containing from 14 to 20 carbon atoms per molecule. The latex is foamed in the presence of a foaming agent other than saturated fatty acid soap, forming a vulcanised foam rubber.
62. THE NATURAL RUBBER PRODUCERS' RESEARCH ASSOCIATION.
Improvements in or relating to the bonding of rubber.
B.P. 1, 338, 830; appl. 20.1.71; publ. 28.11.73.
The present invention provides a method of effecting adhesion between a natural or synthetic rubber and another material which method comprises heating a mixture of the rubber with, (a) an aromatic nitroso compound having the formula X-Ar-NO where X is a hydroxyl or a primary or secondary amine group and Ar is an aromatic group and (b) a polyfunctional linking agent, under pressure in contact with the material to which it is to be adhered. This is to react the rubber with the aromatic nitroso compound, and also pendent amino or hydroxyl groups in the resulting product with the polyfunctional linking agent so as to crosslink the rubber and the said other material. An advantage of this invention is that chemicals added to the rubber have the twin effects of vulcanising the rubber and of effecting bonding of the rubber to other materials.
63. SIN, S.W.
Improvements in or relating to the stabilisation of natural rubber.
B.P. 1, 373, 630; appl. 21.2.71; publ. 13.11.74.
This invention provides a method of treating natural rubber to stabilise it against undesired hardening on storage. It comprises adding to natural rubber in the solid state, hydroxylamine or an acid addition salt. Offering the following advantages, it is possible (a) to produce viscosity stabilised rubber from solid natural rubber of any origin (b) to produce viscosity stabilised rubber with a more efficient use of additive since none of the water-soluble chemical agent is lost during processing (c) to produce viscosity stabilised rubber at any desired viscosity. The application of this viscosity stabilising principle to dry compounding such as in retread compound production is desirable as the final compound maintains its viscosity on storage.
64. SMITH, J. F.
Treatment of rubber.
B.P. 1, 366, 934; appl. 10.8.71; publ. 18.9.74.
This invention relates to natural rubber, both vulcanised and unvulcanised and to a method of removing proteins from natural rubber. The method comprises incubating natural rubber latex with a proteolytic enzyme at a pH suitable for the enzyme in the presence of a soap to prevent premature thickening of coagulation of the latex and subsequently separating proteinaceous material from rubber. The acid constituent of the soap is one of the carboxylic acids from rubber soluble zinc salts.
65. GREGORY, M.J.
Plant growth regulation.
B.P. 1, 393, 112; appl. 26.4.72; publ. 7.5.75.
A process for regulating plant growth including the stimulation of latex flow by applying to the plant on effective amount of a chemical formula:
X - CH2 - CH2 – Sl
where, X is a halogen atom or an orthosphosphate, a mono- or di-orthophosphate ester, or a disubstituted sulphonium salt.
66. CHIN, P.S.
Dispersible natural rubber.
B.P. 1, 448, 205; appl. 17.9.72; publ 2.9.76.
The present invention relates to the preservation of natural rubber latex in the form of re-dispersible solids or low moisture content pastes. It comprises providing a whole natural rubber latex in admixture with dispersing agent combination which includes at least one compound selected from at least two of the groups: (a) glycosides and urea, (b) mono- and di-saccharides, and (c) alkali metal and ammonium salts of organic acids having a C7 and C30 aliphatic carbon chain, and removing water from the latex. The invention is applicable to whole natural rubber latex irrespective of the solids content. The method is applicable to fresh field, diluted field, concentrated and preserved concentrated latices.
67. CHIN, P.S.
Dispersible synthetic rubber.
B.P. 1, 488, 206; appl. 17.8.72; publ. 2.9.76.
This invention provides a method of making a solid or pasty synthetic rubber which is dispersible in water, which method comprises providing a latex of the synthetic rubber in admixture with an effective amount of re-dispersing agent, and removing sufficient water from the latex to give the solid or pasty rubber. The invention also includes synthetic rubber in solid or paste form, which contains a re-dispersing agent and is dispersible in water. It is particularly applicable to styrene-butadiene-rubber (SBR) and polyisoprene rubber.
68. JOHN, C.K.
Treatment of latex.
B.P. 1, 431, 176; appl. 5.7.72; publ. 7.4.76.
The present invention provides a method of treating latex to suppress bacterial acid production. The method comprises maintaining ammoniated whole field latex of Hevea brasiliensis at a temperature of from 40°C-60°C for a period of at least 24 hours. The ammonia is preferably present at a concentration of at least 0.2%, and preferably about 0.3%. The latex is preferably maintained at the minimum temperature at which control of VFA is achieved, which was found to be about 45°C. The use of temperatures above 60oC, adversely affects the latex properties and is expensive on fuel.
1977
69. CAMBELL, D.S., SMITH, J.F. and GELLING, I.R.
Treatment of natural rubber.
B.P. 1, 472, 064; appl. 7.6.74; publ. 27.5.77.
The storage hardening of natural rubber is reduced or eliminated by treatment of fresh natural rubber with an acid hydrozide containing the group -CO-NH NH2. The preferred range of addition is 0.1 to 1.0 p.p.h.r. A suitable hydrazide is naptenic acid hydrazide.
70. RUBBER RESEARCH INSTITUTE OF MALAYSIA.
Coagulation of rubber latex.
B.P. 1, 484, 342; appl. 2.9.74; publ. 1.9.77.
This invention provides a method of producing raw solid natural rubber bulk form. The method comprises passing a continuous stream of fresh or preserved natural rubber field latex through a heat exchanger in which the heating medium is maintained at a temperature from 100°C to 300°C so as to raise the temperature of the latex from 60°C to 110°C . Gelation of the rubber is caused to take place rapidly; optionally crumbling and drying the coagulum; and then pressing and palleting it to form raw solid natural rubber in bulk.
71. KNIGHT, G.T.
Treatment of rubber latex.
B.P. 1, 471, 966; appl. 18.11.74; publ. 27.4.77.
Rubber-bound antioxidants are produced in latex by reacting it with nitroso compounds in the presence of a metal dialkyl dithiocarbamate and a hydroxylamine salt. The reaction is carried out at 50-70°C. The process gives latices which do not discolour on standing. The ageing resistance of vulcanisates prepared from them is equivalent to that obtained by the addition of 1 p.p.h.r. of conventional antioxidant.
72. ONG, C.O.
Treatment of rubber.
B.P. 1, 484, 252; appl. 22.10.73; publ. 1.9.77.
This invention provides a method to provide viscosity stabilisation by adding to fresh solid natural rubber with an aqueous solution of semicarbazide or an acid addition salt. The amount of semicarbazide or acid solution salt added to the rubber is from 0.02% to 0.05% by weight based on the weight of the rubber.
73. DICKENSON, P.B.
Composition containing plant growth regulants.
B.P. 1, 498, 004; appl. 21.12.73; publ 18.1.78.
This invention provides a composition for the treatment of living plants. It comprises a volatile or gaseous plant growth regulant releasably adsorbed on the surface of a particulate solid adsorbent together with an oliphatic or aromatic carboxylic acid or anhydride and/or dimethylsulphoxide and/or glycerol as an agent, to assist assimilation of the plant growth regulant by the plant.
74. JOHN, C.K., LAU, C.M., NG, C.S., RAMA RAO, P.S. and NADARAJAH, M.
Preservation of natural rubber latex.
B.P. 1, 517, 025; appl. 20.8.75; publ. 5.7.78.
The invention provides a method of preparing a preserved natural rubber latex concentrate which method comprises (a) field latex preserved from coagulation from 0.05% to 0.4% by weight of alkali, preferably ammonia, and a secondary preservative, which is a combination of an organic disulphide with zinc oxide or a bactericide (b) concentrating the field latex and (c) preserving the resulting latex concentrate by incorporating a further amount of a secondary preservative and optionally by incorporating further alkali to maintain the alkali concentration within the range 0.05% to 1.0% by weight.
75. YEOH, C. S.
Stimulation of rubber yield from Hevea brasiliensis.
B.P. 1, 498, 948; appl. 2.10.74; publ. 25.1.78.
This invention relates to the stimulation of yield of rubber latex from Hevea brasiliensis through the application of formulations that contain ethylene or ethylene releasing compounds. This invention is based on the discovery that palm kernel oil and coconut oil can be very effective carriers. Accordingly the invention provides a composition for stimulating the yield of rubber latex from Hevea brasiliensis comprising a yield stimulant of the kind which releases ethylene in contact with the plant tissues in a carrier comprising palm kernel and/or coconut oil.
76. YEOH, C.S., RAO, B.S. and TAN, A.M.
Fungicides for controlling tapping panel diseases.
B.P. 1, 505, 027; appl. 2.9.75; publ. 15.3.78.
This invention relates to compositions that will prolong the period of effectiveness of fungicides used for controlling stem diseases of Hevea brasiliensis, in particular diseases on the tapping panel. The invention provides an oil in water emulsion containing a vegetable oil, a hydropholic colloid, and fungicide selected from phenyl mercury acetate, cycloheximide and captafol for application to Hevea brasiliensis.
77. YEOH, C.S., SOONG, N.K., SEKHAR, B.C., PUSPHARAJAH,
E. and RAO, S.
Uses of rubber.
B.P. 1, 508, 304; appl. 29.3.74; publ. 19.4.78.
The present invention relates to the treatment of soil to improve the soil structure and in particular to techniques involving application of aqueous compositions containing rubber and oil to soil. It is primarily directed to two applications. Firstly, to control erosion of exposed soil, especially by heavy rainfall and on sloping terrain e.g. road cuttings and agricultural land, thereby reducing silting of natural waterways, loss of fertility and damage to installations. Secondly, it aims to improve the physical condition of soils, particularly sandy soils leading to better crop growth. This invention provides a method of improving the properties of soil by applying to it, 10³ to 105 litres per hectare of a mixed aqueous emulsion of rubber latex and an oil, containing from 0.05% to 30% by weight rubber (dry basis), from 0.5% to 30% by weight of oil and from 1% to 50% by weight on the weight of the oil of an emulsifier. Examples relating to the aspects of prevention of soil erosion and improvement of the physical conditions of soil are illustrated.
78. DAWES, K. and ROWLEY, R.J.
Azosilanes and their use in reinforced rubber.
B.P. 1, 538, 256; appl. 6.2.76; publ. 17.1.79.
This invention relates to chemical compounds and to their use in rubber which is reinforced with silica. The main utility of the azosilane compounds of the present invention is envisaged as treating agents to improve the compatibility of silica, silicates and clays when compounded in rubber.
79. LIM, T.M.
Fungicide.
B.P. 1, 596, 262; appl. 13.10.76; publ. 26.8.81.
This invention relates to fungicidal compositions and in particular to a method of controlling Secondary Leaf Fall (SLF) in particular Oidium SLF of mature rubber using such fungicides. The fungicidal composition comprises of an emulsion or dispersion of a systemic fungicide in a light hydrocarbon oil which is non-phytotoxic to young rubber leaves. In order to enhance the stability and dispersibility of the emulsion, the composition preferably includes a surface-active agent. The fungicide is primarily intended for spraying or fogging onto rubber trees so as to inhibit the organisms causing SLF.
80. CHEONG, S.F., LAU, C.M., LIM, H.S., SUBRAMANIAM, A. and ONG, C.O.
Preservation of latex.
G.B. 2, 011, 933 B; appl. 10.1.79; publ. 19.5.82
This invention relates to a method of maintaining the colloidal stability of natural field latex, obtained from Hevea brasiliensis, by the use of substances that are not bactericides or enzyme poisons. This permits the growth of micro-organisms in the latex system with the result that certain properties of the derived rubber are changed beneficially. Such stabilised latex is particularly suited for subsequent gelation by physical agents, such as heat or mechanical energy, prior to processing into dry rubber. Fresh field latex is stabilised against coagulation by adding to it an effective amount of anionic surfactant which has a hydrophilic-lipophilic balance value of at least 12 either alone or in combination with small quantities of ammonia and seeding the fresh latex with a portion of mature preserved latex. The amount of surfactant will be from 0.1% to 3% by weight on the dry rubber content (drc) of the latex. Where ammonia is used in combination with a surfactant, the amount used will be typically up to 0.15% by weight on the weight of the latex and amount of surfactant from 0.1% to 1% by weight on drc. Use of less than 0.1% surfactant does not generally give sufficient stabilisation to be of practical value, and use of more than 3% or 1% respectively, for ammonia-free and low-ammonia systems provides no further stabilisation and is uneconomical.
81. ABRAHAM, P.D. and ANTHONY, J.L.
Rubber tapping instrument.
G.B. 2, 048, 748 B; appl. 25.4.80; publ. 24.11.82.
This invention relates to an instrument for extracting latex from Hevea brasiliensis and other rubber latex bearing species. An incision technique known as micro- or puncture-tapping has been experimented with and has been shown, with chemical stimulation, to give yields comparable with conventional excision tapping. Puncture tapping entails puncturing a series of holes, typically using a ca.1.0 mm diameter needle, along a vertical strip or groove of scraped bark 80 cm-100 cm long. To maintain the required level of latex yield, a latex stimulant is usually applied to the scraped bark. This puncture method of tapping can be performed very rapidly and requires little skill. The instrument used to effect tapping comprises a bradawl-like tool, having a short removable needle attached to a handle. This tool, although convenient, has numerous shortcomings. In order to use the tool, the needle is pushed into the tree and then retracted; this operation repeated many times over during tapping of a large number of trees. The double operation requires considerable effort and thus muscle fatigue sets in, typically after about one thousand punctures have been made. The present invention seeks to improve on the existing tools used for rubber tapping, particularly incision tapping.
82. CHEN, S.F. and YEOH, C.S.
Uses of natural rubber.
G.B. 2, 105, 728 A; appl. 20.8.81; publ. 30.3.83.
This invention relates to the use of natural rubber (NR) in the manufacture of coated agricultural materials. In particular it relates to the manufacture of slow release fertilisers by coating fertiliser materials with a coating of NR derived from modified NR latex.
83. JOHN, C.K., CHAN, B.L. and ABDUL LATIFF BIN ABDUL MAJID.
Processing of Hevea latex.
G.B. 2, 098, 222 B; appl. 6.5.1982; publ. 15.8.1984.
The present invention relates to the processing of Hevea latex into dry rubber. It provides a method of producing solid coagulated natural rubber which comprises (a) ammoniating field latex, preferably freshly tapped filed latex, to a pH of at least 9.0 and preferably 9.5 (b) stabilising the ammoniated latex an a nonionic surface active agent (c) fermenting the ammoniated latex for a period of at least 3 days under anaerobic conditions (d) treating the ammoniated, stabilised latex, before or during fermentation with at least one proteolytic enzyme (e) during the fermentation and enzymatic treatment maintaining the pH of the latex at least 9.0 and preferably at about 9.5 (f) optionally diluting the fermented and enzymatically treated latex with water and (g) coagulating the latex with acid.
84. YEOH, C.S. and CHEN, S.F. (Assignee: PETRONAS).
Protein degraded pre-vulcanized natural rubber coated slow release fertiliser.
U.S.P. 4, 549, 897; appl. 17.8.82; publ. 29.10.85.
An agricultural material composition comprises particles of an agricultural material, e.g. a fertiliser, coated with a layer of protein degraded pre-vulcanised natural rubber to provide slow-release properties. The particles preferably have a diameter of from 0.5 mm to 12 mm, and the thickness of the rubber layer is preferably from 10 microns to 250 microns.
85. CHEN, S. F.
A method for the treatment of natural rubber field latex.
G.B. 2, 179, 355 B; appl. 19.7.86; publ. 2.8.89.
This invention relates to the use of natural rubber (NR) field latex for the production of epoxidised natural rubber (ENR). In particular it relates to a method of treatment of NR field latex so that ENR can be prepared from it.
86. GAZELEY, K.F. and MENTE, P.G.
Method for reducing the molecular weight of rubber in latex.
G.B. 2, 183, 663 B; appl. 2.12.86; publ. 20.6.90.
The present invention provides a method for reducing the molecular weight of rubber in latex which has a number of advantages, in particular, the range of temperature over which the reaction may be performed, the wide range in extent of reduction in molecular weight which can be achieved and the relative ease of control over the extent of reduction. The process comprises adjusting the pH of the latex to an appropriate value in the presence of a suitable surfactant, where necessary, and treating the latex under specified conditions with a combination of an oxidising agent and a reducing agent, that is, a redox system. Preferred oxidising agents are peroxidic compounds, which may be hydrogen peroxide, or its organic derivatives such as alkyl, cycloalkyl and aralkyl hydroperoxides, or inorganic peroxy compounds such as perborates, percarbonates, perchlorates and persulphates. Preferred reducing agents are alkali and alkaline earth metal nitrites, ammonium nitrate, alkyl nitrites such as amyl nitrite, and sodium and potassium chlorite.
87. GAZELEY, K.F. and MENTE, P.G.
(same as above - reapplied in Malaysia)
Method for reducing the molecular weight of rubber latex.
MY-100304-A; appl. 28.11.86; publ. 11.8.90.
A method for reducing the molecular weight of rubber in latex form or in wet coagulum form comprises treating the latex with an oxidizing agent and a reducing agent. The oxidizing agent is air, oxygen or peroxide and the reducing agent is a metal nitrite and/or a metal chlorite. The method is particularly suited for use with natural rubber latex, including epoxidised natural rubber latex. Depending upon the degree of reduction of the molecular weight, the method may be used (i) in the preparation of liquid rubber, (ii) in the preparation of improved latex adhesives and (iii) in the control of the viscosity of rubber during normal production.
88. CHEN, S.F.
A method for the treatment of natural rubber field latex.
MY-101622-A; appl. 19.9.87; publ. 17.12.91.
A method for the preparation of epoxidised natural rubber (ENR) from fresh natural rubber field latex is described. This comprises (i) incubating the field latex with a proteolytic enzyme at a pH suitable for the enzyme, (ii) epoxidising the enzyme-treated field latex to the desired mole % level of epoxidation, (iii) coagulating the epoxidised natural rubber latex, and (iv) crepeing, washing, crumbling and drying the epoxidised natural rubber. The amount of enzyme present and the incubation conditions are such that the enzyme-treated field latex, when subsequently processed into ENR latex, has improved coagulation and crepeing properties.
89. KHOO, T.C. and CHE SU BINTE MT SAAD
Method and apparatus for the coagulation of natural rubber latex.
MY-101851-A; appl. 19.9.1987; publ. 231.1.1992.
A continuous method for coagulating natural rubber latex comprises passing a stream of latex through a vertical column. The latex travels down the column as a thin film on the inner surfaces thereof until it comes into contact with steam that has been injected into the column. The latex is rapidly heated by the steam and coagulates, the resulting coagulum being collected at the bottom of the column. The method is particularly suitable for the coagulation of epoxidised natural rubber latex. Apparatus for performing this method is also described.
90. LOO, C.T.
Adhesive compositions based on epoxidised rubber.
G.B. 2, 223, 019 B; appl. 21.7.89; publ. 22.4.92.
This invention relates to novel adhesive compositions derived from epoxidised cis-1,4 polyisoprene. In particular, it relates to the adhesive compositions based on epoxidised natural rubber (ENR) for bonding rubbers to a variety of substrates including metals and rubbers. The adhesive composition comprises epoxidised natural rubber with an epoxide content in the range of from 1 to 90 mole % and optionally, a filler in an amount of up to 100 parts by weight per 100 parts by weight of the epoxidised natural rubber and also at least one of the following: a carboxylic acid, a chlorinated polymer, and a phenolic resin.
91. TAJIMA, Y., KABASAWA, T. and LAU, C.M. (Yokohama Rubber Co. Ltd. and the RRIM)
Natural rubber serum concentrate and method of making the same.
MY-106283-A; appl. 30.12.89; publ. 29. 4.95.
Serum concentrates are disclosed which consisting essentially of specified contents of a non-rubber component remaining in aqueous solutions resulting from coagulation of and separation of all rubber hydrocarbons from natural rubber latices. The non-rubber component includes proteins, saccharides and other important materials. The concentrate product is applied particularly to fertilisers, rubber additives and bacterial culture media.
92. KAIDA BIN KHALID (RRIM and UNIVERSITI PERTANIAN MALAYSIA)
Apparatus and method for the determination of the dry rubber content of rubber latex.
MY-106441-A; appl. 17.8.90; publ. 30.5.95.
Apparatus for the determination of the dry rubber content of rubber latex, by the detection of reflected microwave signals, includes a meter component (1) and a sensor component (2). The sensor comprises a microwave oscillator (18), a transmitter (5), a receiver (6) and a microwave detector (19). During operation, the sensor is immersed to a predetermined depth in-the sample of rubber latex under analysis. In an alternative embodiment, the sample of rubber latex is held within a container, either fixed or removable, positioned adjacent to the sensor. The apparatus is capable of giving accurate and rapid results, and is sufficiently portable and simple to operate to be suitable for use in the field. A method for determining dry rubber content, involving the use of the aforementioned apparatus, is also described.
93. LOO, C.T.
Adhesive compositions.
MY-106610-A; appl. 21.7.89; publ. 30.6.95.
Adhesive composition based on epoxidised natural rubber may be used as cover adhesives to bond a variety of vulcanisable and vulcanised rubbers to metals or to themselves. These adhesive compositions comprise epoxidised natural rubber with an expoxide content of from 1 to 90 mole%, preferably about 50 mole% and optionally a filler and/or a curing agent. In addition, the compositions also comprising at least one of a carboxylic acid, a chlorinated polymer and a phenolic resin have use as general purpose primer adhesives for metals and as single coat adhesives for bonding unprimed metals and chlorinated polymers. The adhesive compositions additionally containing from 10 to 60% by weight of sulphur have use in bonding polar and non-polar robber to primed or unprimed metals and to themselves.
94. UDAGAWA, Y., MACHIDA, M. and OGAWA, S. (YOKOHAMA RUBBER CO. LTD. and the RRIM)
Method of recovering L-Quebrachitol from rubber latex serums.
MY-106594-A; appl. 5.7.89; publ. 30.6.95.
Purified L-quebrachitol can be recovered in increased quantities from serums byproduced upon treatment of rubber latices. Concentrated solutions or pulverised solids of serums are dissolved in selected grades of methyl alcohol and under specified extraction conditions.
95. KONG, H.W., HALIMONTON HJ. MANSOR, KHOO, K.C. and HARRIS, E.M. (FOREST RESEARCH INSTITUTE OF MALAYSIA and the RRIM)
Method and apparatus for the pyrolysis of wood with by-product recovery.
MY-107320-A; appl. 18.6.90; publ. 30.11.95.
A semi-continuous method and apparatus for pyrolysis of wood such as rubber wood into charcoal and other by-products, comprising a step of heating wood placed inside an inner retort (10) within an outer retort (20) and a step of partially condensing the issuing vapour. As a result, charcoal is obtained in the retort (20), tar in a tar separator (40), and pyroligneous acid and other gas fractions in a receiver (60). This process is clearly illustrated in
Figure 1.
1996
96. BOFFEY, S.A., JONES, H., SLATER, R.J., AROKIARAJ, P., CHEONG K. F., WAN ABDUL RAHAMAN BIN WAN YAACOB and YEANG, H.Y. (RRIM and the University of Hertfordshire)
Method for the production of proteins in plant fluids.
USP 5, 580, 768; appl. 17.11.93; publ. 3.12.96
A method of producing a genetically transformed fluid-producing plant comprises: i) inserting into the plant tissue a gene or gene fragment controlling the expression of a target product, and ii) regenerating a plant from said tissue, the genetically transformed plant being capable of expressing the target product in the fluid that it produces. There are also provided clones of genetically transformed fluid-producing plants which contain in their cells a chromosomal insert such that the target product is expressed in the fluids that the plants produce. There is further described a method of producing a protein or other target product which comprises: i) harvesting the fluid from a genetically transformed fluid-producing tree or plant, or a clone thereof, and ii) recovering the target protein or other product from said fluid. Most preferably, the plants are rubber (Hevea) plants and the genes are foreign genes that code for pharmaceutically valuable protein products which can be harvested in the latex produced by the plants.
97. NORDIN BIN ABDUL KADIR BAKTI
Apparatus for effecting gas-liquid contact and use thereof.
ID 0, 002, 053; appl.: 12.12.91; publ.: 10.10.97.
MY-113366-A; appl.: 19.05.91; publ.: 28.02.2002.
Apparatus for effecting gas-liquid contact comprising a vertical column (1) through which the gas and the liquid are passed countercurrent to one another. The column has an axially located rotatable shaft (2) upon which is mounted on or more discs (3), which may have vanes (7). The column also includes a feed distribution tray (4) and at least one liquid redistribution tray (5), either or both of which trays may contain tubes (11) permitting the passage of gas, located at intervals along its length. The apparatus is intended for use in transferring gas dissolved in a liquid flowing downwards through the column, or for transferring a soluble component in a gas-phase mixture into a liquid absorbent. It is particularly suited for use in the removal of ammonia from skim latex during rubber processing
operations.
98. ZAHID BIN MOHAMAD, TUAN MOHAMAD BIN TUAN MUDA and MOHD SIDEK BIN MOHD DIN
Devices for tapping a latex-bearing tree.
MY-109380-A; appl. 10.10.92; publ. 21.1.97.
A device for tapping a latex-bearing tree includes a frame (11, 12) for attachment to the tree, and an operating mechanism which is carried by the frame (11, 12) and comprises a punch (26) and means (16) to drive the punch (26) into the bark of the tree and then to withdraw the punch (26). After each such operation the operating mechanism (16) is moved (30, 32) a step virtually relative to the frame by a motor (18). The motor (18) serves also to actuate the operating mechanism. The most illustrative drawing is Figure 1.
1999
99. SIVAKUMARAN, S.
Improvements in the method of stimulation and tapping of Hevea brasiliensis.MY-111156-A; appl. 1.3.91; publ. 20.9.99.
There is disclosed improvements in the method of stimulation and
tapping of Hevea brasiliensis, which improvements comprise of treating
Hevea trees with gaseous ethylene for stimulation of latex flow and
tapping such treated trees with tapping systems comprising of punctures for
increased latex flow and higher yield productivity. An applicator is fixed
over a previously bored hole on the tapping panel and the ethylene gas is
fed through a tube fitted into the bored hole through an aperture on the body
of the applicator. The bored hole and applicator are positioned on the bark of
the tapping panel at the desired location on the trunk of the rubber tree.
112. HAN, K-H., KANG, H., OH, S.K., CHOW, K.S., FARIDAH BT. YUSOF, YEANG, H.Y.
(KOREA KUMHO PETROCHEM CO LTD. and MALAYSIAN RUBBER BOARD)
Recombinant microorganisms expressing small rubber particle-associated protein
EP 1050582-A2; appl. 25.6.99; publ. 8.11.00
Also published as:
JP 2000 316586-A; appl. 18.8.99; publ. 21.11.00
The present invention relates to cDNA encoding small rubber particle-associated protein (SRPP) which binds to small rubber particle derived from the latex of H. brasiliensis, recombinant SRPP deduced from the cDNA, recombinant microorganisms transformed with the recombinant expression vectors and method for synthesis of rubber using the recombinant SRPP. The recombinant SRPP expressed in the recombinant microorganisms can be applied for the rubber synthesis in the presence of rubber particle.
113. HAFSAH BT. GHAZALY
Preparation of low protein latex
MY-112788-A; appl. 15.11.94; publ. 29.9.01
A process of treating latex is described in which a fatty acid soap and a non-ionic surfactant are added to the latex in proportions such that the colloidal stability of the treated latex is such the latex is suitable for dipping processes. In an example the fatty acid soap is potassium laurate and the non-ionic surfactant is alkyl phenol ethoxylate.
114. CARDOSA, M.J., SHARIFAH BT. HAMID, SAMUEL-VERGHESE, S., SUNDERASAN, E., YEANG, H.Y., SAMSIDAR BT. HAMZAH
Allergenic protein HEV b III of natural rubber latex, its production and use in assays.
E.P. 1 350 797-AI; appl. 15.9.95; publ. 8.10.03
Remarks:
This application was filed on 17.04.2003 as a divisional application to the application mentioned under INID code 62.
This invention relates to allergenic proteins of natural rubber latex in substantially purified form, their production and their use, together with monoclonal antibodies developed against those allergenic proteins, in assays for the qualitative and quantitative determination of the levels of the allergenic proteins in natural rubber latex or in products made from latex. Assays for identifying and/or quantitating antibodies in blood or blood products that mediate the occurrence of an allergic reaction induced by natural rubber latex are also provided, together with in vivo and in vitro diagnostic tests for detecting hypersensitivity to natural rubber latex and which involve use of the aforesaid allergenic proteins. The invention also provides for the use of the aforesaid allergens as de-sensitising agents in the treatment of latex protein allergy. There is still further provided a method for removing allergenic proteins from latex products.
115. AROKIARAJ, P. PUJADE-RENAUD, V., and JONES, H.
(MALAYSIAN RUBBER BOARD, CTE COOPERATION INTERNATIONAL and UNIVERSITY OF HERTFORDSHIRE, UK.)
Promoter sequences from Hevea brasiliensis hevein genes.
WO 2004 /101641-AI; appl. 16.5.03; publ. 25.11.04
The present invention relates to the isolation of DNA sequences from the Hevea brasiliensis containing the promoter and regulatory region of hevein genes. The promoter sequences of the hevein genes also act as an inducible promoter regulated by wounds and pathogen infection.
116. SITI ARIJA BT. MAD ARIF, CHEW, N.P., and YEANG, H.Y.
Allergenic protein of natural rubber latex.
EP 1 481 991; appl. 27.2.04; publ. 1.12.04
Also published as:
DE 60 2004 004 312-T2; appl. 27.2.04; publ. 14.11.07
US 7,329,512-B2; appl. 27.4.04; publ. 12.2.08
The present invention relates to a protein found in natural rubber that can induce an allergic reaction in persons who have been sensitised to it. The invention provides for the process of isolating and purifying the protein and describes the characteristics of the protein, including its molecular weight, isoelectric point, amino acid sequence and allergenicity. The invention also describes the isolation and cloning a the DNA that encodes the protein. The production of the recombinant version of the protein using a protein expression vector is described.
117. SUNDERASAN, E., SITI ARIJA BT. MAD ARIF, and YEANG, H.Y.
Allergenic protein complex of natural rubber latex
US 2005/0227292-AI; appl. 18.3.05; publ. 13.10.05
Also published as:
EP 1604 996-A3; appl. 9.3.05; publ. 21.12.05
The invention relates to the allergenic latex protein Hev b 4. The full cDNA sequence of the smaller protein components of Hev b 4 is disclosed, together with the amino acid sequence of those components and the synthesis of a recombinant protein using the aforesaid DNA sequence or a synthetic peptide derived from the amino acid sequence. The use of the Hev b 4 protein complex and of an antibody against that protein is described in immunoassays and in immunotherapy for the relief of allergy or allergy symptoms.
118. NORDIN BIN ABDUL KADIR BAKTI, ZAIROSSANI BIN MOHD NOR, MOHD ZIN BIN ABDUL KARIM, MOHD. SIDEK BIN MOHD. DIN and TUAN MOHAMAD BIN TUAN MUDA
Apparatus for the extraction of natural rubber field latex under aseptic conditions
MY-122188-A; appl. 16.8.99; publ. 31.3.06
Apparatus for extracting latex from rubber latex bearing species comprising a housing with a moveable rod wherein a puncture is made in the tree bark using the rod and latex flows through the housing passage and a tubing into a closed container with an air filter. One end of the housing is in the form of a cup of attachment to tree bark. The housing also contains a valve for sealing the housing passage after puncturing. The apparatus is intended for extracting natural rubber field latex that can be processed to give a high quality rubber due to the absence of chemical preservatives and minimal amount of acid used for late coagulation. In addition, the liquid-phase containing the non-rubber components can be obtained in the original form without toxic chemical additives. This permits the production of non-toxic liquid from field latex that contains valuable biochemicals for further exploitation.
119. NARIMOTO, K., EIJI, M., AMIR HASHIM and ASRUL BIN MUSTAFA
(NAGAOKA UNIVERSITY OF TECHOLOGY AND MALAYSIAN RUBBER BOARD)
Modified natural rubber and the method for preparation thereof.
JP2007-112937 A; appl. 21.10.05; publ. 10.5.07.
To provide at a low cost a modified natural rubber having improved properties such as oil resistance and being capable of being used in various uses as a functional material by utilizing as a raw material for modifying the natural rubber vegetable-origin cinnamic acid derivatives and cinnamaldehyde derivatives obtained by decomposing lignin, etc., heretofore disposed of as wastes. The modified natural rubber is produced by polymerizing vegetable-origin cinnamic acid derivatives and cinnamaldehyde derivatives having polymerizable unsaturations onto a deproteinized natural rubber. It is desirable that the vegetable-origin cinnamic acid derivatives and cinnamaldehyde derivatives optionally together with a vinyl monomer are grafted onto the deproteinized natural rubber.