Neoprene Compounds

Use of a good antioxidant is recommended for almost all neoprene compounds where color is not of importance, a staining antioxidant can be used. The substituted or hindered phenols, eg, Naugawhite (Uniroyal) and Antioxidant 2246 (American Cyanamid), are used where a minimum of product discoloration or staining is requited. 

W. Schmidt, Curing Systems for Neoprene, Du Pont Bulletin NP-330.1,1982 J. C. Bament, Neoprene Compounding and Processing Guide Plus Formulary, E. 

The resilience of gum neoprene vulcanizates is little lower than natural rubber but it decreases with increased filler incorporation. Therefore, the resilience of most practical neoprene compounds is higher than that of natural rubber with comparable volume loading. Because of the presence of chlorine in the neoprene molecule, products made from neoprene resist combustion to a greater degree than products made from non-halogen bearing rubbers. This means neoprene can be compounded to meet the flammability requirements of the Mine Safety and Health Administration (MSHA) USA or similar requirements as might be stipulated by any other countries,... 

Use Protection of light-colored rubber from oxidation and of nonstaining neoprene compounds against deterioration. 

Table 3.3 Typical ozone resistant Neoprene compound for cell house application ...

This is essentially hydrated aluminium silicates derived from natural deposits. There are soft clays, hard clays, calcined clays and treated clays. This is a common filler in the manufacture of acid resistant ebonites, natural soft rubbers and in Neoprene compounding for phosphoric acid duties. 

Sodium acetate is an efficient retarder for Neoprene compounds. It is selectively preferred for mercaptobenzothiazole or benzothiazyl disulfide since its retarding effect does not persist at normal curing temperatures. 

Red lead is an ingredient generally used in all Neoprene compounds for tank linings for good water and chemical resistance. But it should not be used in compounds of Neoprene designed for contact with food or potable water. Tubes or pipes for conveying potable water are made of ethylene-propylene diene terpolymer (EPDM) rubbers. 

OTHER COMMENTS This chemical presented limited information with regard to its physical and chemical properties. This chemical has not been well tested for heath effects. It is used in making plastics and rubber products this substance has also been used to protect light-colored rubber from oxidation and non-staining neoprene compounds from oxidation. 

This compound also uses Neoprene W type polychloroprene rubber. The compound, though coloured black with a few parts of carbon black is mainly filled with silica, which is a reinforcing mineral filler. The silica also helps to bond the rubber to the steel cords other ingredients added for this purpose include cobalt naphthenate. A commonly used system for this purpose is one comprising resorcinol and hexamethylene tetramine (HMT) which acts as a formaldehyde donor to form a phenolic resin in situ, but this is not suitable for Neoprene compounds because resorcinol is a fast accelerator for Neoprene vulcanization and interferes with its processing safety. 

Thompson, D.C. Report 57-1 Practical neoprene compounds of low elastomer content. Rubber Age 72, 17 1953 quoted in The neoprenes, p. 76. E I Dupont De Nemours ... 

Neoprene - In general, neoprene compounds have excellent resistance to all straight-chain hydrocarbons, all aliphatic hydroxy compounds such as methyl and ethyl alcohols and ethylene glycol, animal and vegetable fats and oils, and fluorinated hydrocarbons such as Freon refrigerants. 

Parel elastomer, natural rubber, and neoprene, compounded with standard recommended formulas for each, were heat aged in a 125 C. forced draft oven. Figure 3 is a plot of the change in tensile strength and hardness of the vulcanized Parel and neoprene elastomers. Neoprene maintained its properties for 3 days, but after a week at 125 C., it was quite hard and brittle. Results with natural rubber are not included in the figure because it failed so quickly at 125 C. It was seriously deteriorated in about 3 days at 100 C. 

Sometimes natural rubber latex can be substituted in the RFL dip. This may result in a loss in adhesion. Neoprene latex has also been used in RFL dips, but usually it has more of a specific use, such as with a neoprene compound. 

It gives a neoprene compound good scorch safety and a good cured crosslink density, which is sometimes hard to duplicate with other rubber accelerators. 

Antioxidants. The presence of a good antioxidant in Neoprene compounds is essential for adequate protection against oxidation. Hindered w-phenols, such as Wingstay L or Antioxidant 2246, are usually used where minimum discoloration and/or minimum staining is desired. Where discoloration is unimportant, amine type antioxidants are used. 

For more than a year thereafter the Army s standard service masks— both the M3 lightweight mask standardized earlier and its shortlived successor, the M5 combat mask—were made of neoprene. As in the case of any major change in specifications, there was an occasional hitch on the production lines. Some of these hitches were caused by the fact that batches of neoprene compound were not always uniform. A more critical problem arose when one contractor attempted to produce faceblanks for the complicated optical gas mask from neoprene. The neoprene stock refused to take molding acceptably, and nearly all the first batch of one thousand faceblanks failed to pass inspection. The contract had to be terminated. But with these exceptions, production of neoprene masks proceeded smoothly enough. 

Adipate Diesters Made with Propylene and Dipropylene Glycol n-Butyl Ether Compared to PlasthalTs 203 and 226 in Nitrile and Neoprene Compounds, The HallStar Company Technical Publication. 

FIGURE 15.4 Stmktol materials WB 222 and HPS 11 in a neoprene compound, reinforced with N330 and treated clay and cured with ETU. 

HEAT RESISTANT NEOPRENE COMPOUNDS TO MEET DTD 5514 SPECIFICATION... 

Another example is the use of halobutyl in neoprene compounds as an economy measure. Table 27 illustrates the influence of bromobutyl content on compound cost, tensile strength, oil resistance, compression set, and specific gravity. Air ageing resistance is unchanged. 

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