Neoprene (cr) is the polymerization of ch2= CCL -ch=ch2 (2-chloro-1, 3-butadiene) or their copolymers with other monomers.The important raw material for the manufacture of chloroprene is acetylene.Various types of polychloroprene can be prepared by emulsion polymerization.The process of polymerization can be adjusted to produce non-crosslinked and non-branched polymers (so-called -polymers).A large number of different forms of neoprene can be divided into two categories according to its structure and characteristics:
1. The first type is the sulfur free polymer in the composition, and the important regulator used in synthesis is mercaptan;
2. The second type is chloroprene rubber containing sulfur in the molecular chain, which exists in the form of a polysulfur bridge.The regulators used in the manufacturing process are sulfur or sulfur with mercaptan.The average molecular weight of neoprene is 100, 000 ~ 200, 000.Although polychloroprene has a high degree of unsaturation, it still has high chemical stability and resistance to various forms of aging.This is because the electronegative chlorine atoms on the carbon atoms of the double bond attract PI electron layers, reducing the electron density of the double bond and thus the reactivity of the double bond.The chlorine atom itself loses its activity and reactivity.
Density: 1200 ~ 1240kg/m3.Glass transition temperature: - 40 ℃.Crystalline phase melting temperature: 40 ~ 65 ℃.
The presence of chlorine in polychloroprene makes it noncombustible, while the polarity of the polymer makes it resistant to fatty hydrocarbon swelling and highly adhesive to metals.
At the beginning of the invention, it was developed into an oil-resistant artificial rubber that replaced the raw rubber. As a result, neoprene is still widely used today. In any case, the unique physical combination of neoprene has been applied to more than one thousand kinds of use in the whole industry, among which it is widely known.
The properties of cr depend on the microstructure of the polymer, its processing properties depend on the molecular weight and distribution of the polymer, the number and distribution of branched chains and crosslinks, and its chemical properties depend on the influence of chlorine atoms in the phase edge of carbon atoms.The basic variety of cr is homopolymer of chloroprene.It has regular molecular arrangement and crystallization tendency at room temperature, and its crystallinity decreases with the aging of the polymer.The actual use of cr adhesive type because it is at 20 ℃ below polymerization, its high crystallinity.
Resistance limit, high temperature hot - neoprene has a practical, continuous application range of 80 ~ 95 ℃, in this range, it shows good physical characteristics and application between the exhaust, special formula can reach 120 ℃, exceed this limit does not make neoprene soften or melt, but may cause hardening or loss of elasticity.Cold - - 20 ℃ to 25 ℃ below zero in the application, performance is only a little change, below this temperature, the brittle temperature, 40 ℃ (-) before it hardens, special formula has promised to application of low temperature of 55 ℃ below zero.
Remarkable resistance to wax, fats, oils, lubricants and a variety of petroleum properties.
Good resistance to alkali, dilute mineral acid and inorganic salt solution.
Suitable formulation with good ozone and weather performance.
It can be obviously immersed in water or buried under soil for a long time.
Excellent resistance to bending, twisting and compression.
Made of neoprene products include: wire and cable outer layer, industrial gaskets, rubber hose, belts, fabric, the structure of the construction with gap filling agent, axles, foam products, a variety of adhesives, coatings, industrial/agricultural use, automotive, pressure/molding products, a variety of footwear, paper, packaging, construction and other consumer products.