1.1 introduced butyl rubber
Butyl rubber (IIR for short) is the world's fourth-largest synthetic rubber (SR) type of rubber, is ISO-butylene and isoprene in cationic polymerization of Friedel-Craft catalyst, appearance of white or light yellow Crystal, odorless, very low glass transition temperatures, not soluble in ethanol and acetone.
Properties of butyl rubber is mainly composed of POLYISOBUTYLENE and degree of unsaturation in the main chain structure at the end of the decision, its degree of unsaturation is only 0.5%~3.3% (MOL) is about one-fiftieth of natural rubber, butyl rubber has a number of excellent features.
Butyl rubber has good air tightness and gases through the diffusion of polymer and polymer the thermal motion of molecules related to butyl rubber molecules chains-arranging-intensive, limiting the thermal motion of polymer molecules, low permeability, gas-tightness. Butyl rubber good heat stability and butyl rubber adhesive has excellent thermal stability of sulfur-Vulcanized butyl rubber in 100 ℃ long-term use or slightly lower temperatures in the air, with resin-Vulcanized butyl rubber temperature can reach 150 ℃ to 200℃. Thermal oxidation degradation of the genus of butyl rubber, for softening the aging trend. Butyl rubber has good ozone resistance weather resistance and aging resistance, and high saturation of butyl rubber molecules chains so that it has a high resistance to ozone and ozone resistance weather resistance and aging about superior properties of natural rubber, styrene-butadiene rubber by 10 times. Butyl rubber has sucking can sex (shock performance), butyl rubber molecular structure in the missing double bond, and side chain methyl distribution density larger so has good of absorption vibrations and impact energy of characteristics, in is wide of temperature range within ( -30~-50 ℃) butyl rubber of back play characteristics are not is greater than 20%, this showed that has butyl rubber of absorption mechanical performance of capacity is superior to other rubber, butyl rubber in high deformation speed Xia of damping nature is poly ISO butene chain segment by inherent of, in is big degree Shang, it not by using temperature, Degree of unsaturation level, influence of curing State and formula changes.
Butyl rubber has good chemical stability, high saturated structure of butyl rubber, which has a high chemical stability. Butyl rubber special oils, for most inorganic acids and organic acids have good corrosion resistance, although it is not resistant to strong oxidizing acid, such as nitric acid and sulfuric acid, but non-oxidizing acids and medium-concentration oxidizing acid and alkali solution and redox solution. 70% sulfuric acid for 13 weeks, with almost no loss of strength and elongation of butyl rubber, natural rubber and styrene-butadiene rubber performance has been severely curtailed.
1.2 butyl rubber rubber raw materials
(1) rubber rubber: extraction of plants such as grass, rubber latex from rubber tree after machining is made of elastic material, insulation, waterproof and air. High elastic polymers. There are two kinds of natural and synthetic rubber. Natural rubber from rubber trees, grass and other rubber made from plant derived colloidal processing; is composed of various monomers and polymerization of synthetic rubber. Rubber products are widely used in industry, or in all aspects of life.
Rubber, poor stability, hard to maintain. Operating temperature range: about-45 ¡æ ~+100 ¡æ. Mainly used in the manufacture of ozone and ageing resistance of high demand the cable jacket and protective cover, protective cover; oil-resistant, good resistance to chemical corrosion and chemical hose, tape lining; flame-retardant rubber products used in underground mining, as well as various molded products, seal rings, pads, binders, etc. Butyl rubber (IIR) is isobutene and small amounts of butadiene or isoprene copolymer. Is the biggest characteristic of tightness good, good ozone resistance, ageing resistance, high heat resistance, long-term working temperature can be below 130 ℃; resistant to inorganic acids (such as sulphuric acid and nitric acid) and organic solvents in General, good vibration absorption and damping characteristics, are very good electrical insulation. Disadvantage is the poor flexibility, processability is poor, slow curing speed and poor adhesion and resistance to oil. Operating temperature range:-40 ¡æ ~+120 ¡æ about. Mainly used for inner tubes, water bag, balloons, wire and cable insulation, chemical equipment lining and shock-absorbing products, heat resistant conveyor belts, heat aging of adhesive tape products.
Added to the rubber of various raw materials, collectively known as the rubber compounding.
Softening plasticizing system: classified as softening agents and plasticizers, softeners: General Physics plasticizer for softening oil, by reducing the Intermolecular forces reach the softening effect, reduces the hardness after accession, such as improved low temperature performance. Plasticizer: chemical plasticizers, can break the rubber molecules after accession, so as to achieve the plasticizing effect.
Curing system: curing agent and accelerant, surfactant, anti-coking agent. Due to the curing agents in different curing systems include: sulfur curing system (S-80GA), and contains sulfur vulcanization of peroxide vulcanization (F-40, DCP99%, and DCP40%), metal oxide-sulfide (ZnO-A).
Reinforcing fillers include reinforcing agents and fillers. Reinforcing filler: fills a significant reinforcement of additives after.
Anti aging system: rubber during storage and after a certain time of use, it will harden, crack, sticky, and cannot be used, a phenomenon known as "aging". To obtain a durable rubber products, get a rubber compound is illustrated with some substances that can inhibit this cause rubber. Antioxidant generally refers to wax, it can leach into the rubber to form a protective film on the surface, but play no role in media or dynamic conditions.