Articles, rubber

Rubber Articles. The soHd polysulftde mbber products, Thiokol FA and Thiokol ST, are used ia the manufacture of printing roUers, printing blankets, gas meter diaphragms, O-rings, and specialty molded items. 

Natural or synthetic, mostly low-MW molecules that reduce or suppress microbe populations in plastics. Specialised products (both organic and inorganic) which tend to be used most in plasticised materials such as PVC and polyurethanes, as well as in rubber articles. The main cause of microbial growth is the additives themselves plasticisers, starch fillers, lubricants, thickening agents and oils. 

The ability of a rubber article to withstand wearing away in service. Standard BS 903 Part A9. Determination of abrasion resistance. 

A method of manufacturing rubber articles by pouring a compounded latex into an absorbent hollow mould the skin of rubber thus formed is removed, dried and vulcanised. The term is also apphed to the pouring into moulds of liquid polymer systems based on silicone or polyurethane elastomers. 

Splitting into layers usually applied to the separation of the plies from which a composite rubber article has been built up. 

A method of manufacturing rubber articles by dipping a former of the shape required into a rubber solution or into compounded,... 

A process, now obsolescent, of forming rubber articles on an anode by the migration of coagulating ions resulting from the passage of an electric current. 

A dulling of the surface of vulcanised rubber articles considered to result from the action of atmospheric ozone, particularly in conditions of high humidity. It is quite different from blooming. 

A method of vulcanising thin rubber articles, now of historical interest only. The products are exposed successively to the gases, sulphur dioxide and hydrogen sulphide, which react to form active sulphur which brings about vulcanisation. 

A sheet of rubber or layer of rubbered fabric when prepared as a component of a composite rubber article. 

An undesired discontinuity in a rubber article (uncured or cured) resulting from ply separation or from the trapping of air during assembly or during vulcanisation. 

The presence of small cells or voids in rubber articles. Porosity may be unwanted due to lack of pressure during vulcanisation, or intentional as in cellular rubber. 

In the vulcanisation of thick rubber articles the temperature may be stepped up in stages to ensure adequate heat penetration to the interior before the external surface begins to cure. Such a cure schedule is termed a step cure. Step post cures are used with thick section rubber articles to ensure that volatiles are released gradually without causing damage, such as porosity, due to an over rapid release. 

Kaysam A process for making rubber articles from rubber latex by flocculating it with a mixed electrolyte and then casting in a rotating, porous mold. 

P.R.57 1 is also used for PUR foam products. Problems arise with steam vulcanization, because some color is transferred to the wrapper as the pigment is worked into rubber (Sec. 1.8.3.6). The pigmented rubber articles are not completely fast to a number of organic solvents, to soap and sodium carbonate solutions, and to acids and S02 (Sec. 1.6.2.2). 

Microconcentrations of carcinogenic IV-nitrosamines were determined in various rubber articles (tubing, stoppers, hoses, seals, etc.) for medical and food uses by extraction followed by HPLC-FLD593. V-Nitrosodi phenyl amine (278c) present in diphenylamine formulations was determined by LC-TEA on a Zorbax CN column594. 

Compression molding is one of the oldest materials handling processes. Ancient Chinese employed compression molding to form articles from paper Mache. Rubber articles were made in the early 19th century from composites of woody fibers and gum shellac. Baekeland used compression molding to make many of his early PF products. 

Copolymers of butadiene and acrylonitrile are soluble in aromatic or chiorinated hydrocarbons but insoiubie in aiiphatic hydrocarbons.Therefore they find use in oil-resistant rubber articles (hoses, sealings etc.)... 

Coumarone-indene resin as a plasticizer in rubber articles intended for repeated use in contact vith food Yes CFR 1989d (21 CFR 177.2600)... 

Heat-Sensitizing Process. Another process used to make latex rubber articles of thicker section involves sensitizing the compound so that it coagulates when heated to a given temperature, then using heated molds to build the article to the desired thickness. Ammonia-preserved latex is used in this process, and polyether, polythioether, or poly(vinyl methyl ether) (PVME) can be used as heat-sensitizing agents. 

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