Neoprene grade

No official classification of magnesium oxide for rubber use exists. However, the market provides magnesium oxide with higher surface area as neoprene grade and lower surface area for halobutyl rubber grade. 

Adhesives. Contact adhesives are blends of mbber, phenoHc resin, and additives suppHed in solvent or aqueous dispersion form they are typically appHed to both surfaces to be joined (80). Evaporation of the solvent leaves an adhesive film that forms a strong, peel-resistant bond. Contact adhesives are used widely in the furniture and constmction industries and also in the automotive and footwear industries. The phenoHc resins promote adhesion and act as tackifiers, usually at a concentration of 20—40%. In solvent-based contact adhesives, neoprene is preferred, whereas nitrile is used in specialty appHcations. The type and grade of phenoHc resin selected control tack time, bond strength, and durabiHty. 

Chemical Natural rubber Clove material Neoprene Nitrile Normal PVC High grade PVC... 

Polychloroprene polymers also vary in the degree of branching in the polymer. Polychloroprenes with little or no branching are called sol polymers, whereas those with considerable branching are referred to as gel polymers. Sol polymers are soluble in aromatic solvents. All of the solvent-grade polychloroprene polymers (except Neoprene AG) are sol polymers. The gel content in the polychloroprene affects the cohesive strength, resilience, elongation, open tack time, resistance to permanent set, and oil swell. 

Grade Neoprene Baypren Butachlor Denka Skyprene... 

Neoprene AC (1947). This polychloroprene was developed to provide better viscosity stability and resistance to discolouration, but it cures much more slowly at room temperature. It is a fast crystallizing grade and contains about 90% trans-, 4 structure. 

Neoprene AD ( 95 ). This is more stable than Neoprene AC. This polychloroprene does not change colour in contact with iron and viscosities of the solutions are maintained stable over long periods of time. They are fast ciystallizing grades and contain about 90% trans-1,4 structure. 

New Neoprene M- and XD grades. These polychloroprenes were developed in the 1990s and combine low temperature flexibility, improved heat resistance and dynamic properties. 

Once the <5 and y values of a given blend are determined, the values are positioned in the graphic chart given in Fig. 37 [77]. The blends that fall within the kidney-shaped area yield good solutions with all solvent grade polychloroprene types, except for Neoprene AH, and those which fall outside that area will not dissolve the polychloroprene. The solvent blends which fall within the shadow area, may or may not dissolve the polychloroprene depending on the amount of toluene. 

There are 16 grades of DuPont neoprene alone. They vary in crystallization rate and potential, viscosity, molecular weight, additive content, and other properties ([216], pp. 284-306). Selection of the right materials requires sophisticated knowledge of both the neoprenes and the phenolic additives. Guggenberger provides a good overview of this situation and some basic formulation information ([216], pp. 284-306). She also provides a prototype formula for a heat-resistant contact cement as shown in the Table 18 ([216], source Table 10, p. 293). 

Health Hazards Information - Recommended Personal Protective Equipment U.S. Bu. Mines approved toxic dust mask chemical goggles rubber gloves neoprene-coated shoes Symptoms Following Erqrosure Inhalation produces slight toxic effects. Contact with eyes irritates eyes and causes skin rash General Treatment for Exposure INHALATION remove to fresh air. EYES wash with water for 20 min. call a physician. SKIN wash with water Toxicity by Inhalation (ThresholdLimit Value) Data not available Short-Term Exposure Limits Data not available Toxicity by Ingestion Grade 2 oral rat LDjq 820 mg/kg Late Toxicity Data not available Vapor (Gas) Irritant Characteristics Data not available Liquid or Solid Irritant Characteristics Data not available Odor Threshold Data not available. 

Even as Carothers was explaining the fundamental nature of large biological molecules, he orchestrated a miraculous two weeks in the history of industrial research. During April 1930, he and his team invented not only Neoprene, the first high-grade synthetic rubber, but also polyester, the first synthetic fiber that closely resembled silk. It was a dazzling accomplishment that can still make industrial chemists starry-eyed. 

Robert M. Secor. Telephone interviews, 2000-2001. Source for Sylvia Moore s background and end of their affair club memberships Julian Hill visits hospital and learns Carothers spent the night there before suicide Carothers grades and freshman chemistry class Carothers rejects Neoprene medal European doubts about Carothers condensation polymers and young Flory s opinion that polymers were of dubious scientific value. 

Uses. Rubber accelerator and vulcanizer, as an activator of thiazole accelerators, and as a plasticizer in neoprene pharmaceutical grade used in treatment of alcoholism... 

Food and Brewing Food quality linings for chutes, hoppers, process vessels, mixers, coating pans, pipelines etc. White natural or neoprene food grade linings of 40 to 60°A. 

Compounding and Properties of Bayprene Grade Neoprene Rubbers, Technical Information Bulletin, Bayer AG, Leverkusen, Germany, 1976. 

---