Rubber Latex Products

Journal of Macromolecular Science C C42, No.2, 2002, p.185-234 NATURAL RUBBER LATEX PRODUCTS CONCERNS IN HEALTH CARE Abraham E K Ramesh P... 

Details are given of the Q.C.L.P. (Quality Control in Latex Production) program, developed by Studio di Consulenza of Italy, and its use in the rubber latex products manufacturing industry. 

About 12% is used in making rubber latex products, while another 5% goes into sponge applications. 

Continuous emulsion polymerization processes have been widely used in the large-scale production of latex products. For example, styrene-butadiene rubber latex products are manufactured by such processes consisting of a... 

Natural rubber was one of the earliest industrial polymers to be developed commercially and it was recognised even before it reached the industrialised countries that it very rapidly lost its initial useful properties in the environment. Furthermore, rubber latex products were rapidly attacked by microorganisms, leading to more general loss of mechanical properties and to eventual bioassimilation in the soil environment . 

Fast, low temperature curing mbber compounds can be prepared by initial heat prevulcanisation of the Hquid latex and are marketed commercially (Revultex, Doverstrand Corporation). Rubber deposited from these often needs tittle more heat than that required to dry the deposit, to achieve optimum tensile strength and elongation. Such compounds are often used by small companies manufacturing thin-wall dipped medical latex products, such as examination gloves, as few compound preparation facilities are needed by the dipping company. 

Tyj)e of dryer Applicable with dry-product recirculation True and colloidal solutions emulsions. Examples inorganic salt solutions, extracts, milk, blood, waste liquors, rubber latex, etc. Pumpable suspensions. Examples pigment slurries, soap and detergents, calcium carbonate, bentonite, clay sbp, lead concentrates, etc. does not dust. Recirculation of product may prevent sticking Examples filter-press cakes, sedimentation sludges, centrifuged sobds, starch, etc. 

Natural rubber is harvested as latex by tapping trees in a manner similar to maple syrup. Tree latex contains about 35 wt% rubber solids, as well as small quantities of carbohydrates, resins, mineral salts and fatty acids. Ammonia should be immediately added to the latex to avoid coagulation by these other ingredients and to prevent bacterial degradation. After collection, the latex can be concentrated to 60-70% solids if the latex product is required for end-use. Otherwise, the latex is coagulated, washed, dried, and pressed into bales for use as dry rubber. 

Emulsion polymerization is the most important process for production of elastic polymers based on butadiene. Copolymers of butadiene with styrene and acrylonitrile have attained particular significance. Polymerized 2-chlorobutadiene is known as chloroprene rubber. Emulsion polymerization provides the advantage of running a low viscosity during the entire time of polymerization. Hence the temperature can easily be controlled. The polymerizate is formed as a latex similar to natural rubber latex. In this way the production of mixed lattices is relieved. The temperature of polymerization is usually 50°C. Low-temperature polymerization is carried out by the help of redox systems at a temperature of 5°C. This kind of polymerization leads to a higher amount of desired trans-1,4 structures instead of cis-1,4 structures. Chloroprene rubber from poly-2-chlorbutadiene is equally formed by emulsion polymerization. Chloroprene polymerizes considerably more rapidly than butadiene and isoprene. Especially in low-temperature polymerization emulsifiers must show good solubility and... 

Few data are available on the deposition of ultrafine particles (dradon decay products in a rubber latex cast of a human windpipe which extended from the epiglottis to a few cm below the Carina. Martin and Jacobi (1972)... 

Foam Rubber A product produced exclusively from a liquid base, e.g., latex. Latex foam has an interconnecting cell structure and is most commonly used for cushioning applications. 

This article presents views expressed during a presentation made at the recent Third Annual International Latex Conference, held in Ohio, on the subject of stringent natural rubber latex regulations in the US A. There is a fear that over-zealous regulation of latex products is threatening the entire US latex industry. 

A detailed review is presented of the literature on cutaneous reactions to rubber, the aspects covered including latex allergy, irritant contact dermatitis and allergic contact dermatitis. The adverse cutaneous reactions to rubber occurring following industrial and occupational or consumer exposure to rubber chemicals or products or to natural rubber latex proteins are discussed. 261 refs. 

Vaginal cream contains mineral oil and vaginal suppositories contain an oleaginous base which may weaken rubber or latex products such as condoms, avoid use within 72 hr following treatment with vaginal cream or suppositories... 

Other than tire use, there are few other significantly large application areas for natural mbber that can be identified, as indicated in Table 10. The use of natural mbber in latex products covers items such as gloves, condoms, balloons, catheters and other dipped goods, latex thread, foam and carpet backing, and rubberized coir and hair. In total, latex goods consume about 11% of world mbber production. Thereafter, there are four categories footwear,... 

Phosphoric acid is used as an intermediate in the production of animal feed supplements, water treatment chemicals, metal surface treatments, etching agent, and personal care products such as toothpaste. It is used as a catalyst in the petroleum and polymer industry. Phosphoric acid is used in food as a preservative, an acidulant, and flavor enhancer it acidifies carbonated drinks such as Coca Cola and Pepsi, giving them a tangy flavor. Phosphoric acid is used as a rust remover and metal cleaner. Naval Jelly is approximately 25% phosphoric acid. Other uses for phosphoric acid include opacity control in glass production, textile dyeing, rubber latex coagulation, and dental cements. 

The bacteriostatic and fungicidal properties of boric acid have led to its use as a preservative in natural products such as lumber, rubber latex emulsions, leather, and starch products. 

D-glycerol has been isolated from various red algae,377,378 rubber latex,284 turnips and rapeseed,179,294 and wheat flour.358 It is likely that this compound is a product of enzymic hydrolysis (by D-galacto-lipase)352 of DGDG. 

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