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Rubber formulas with different rubber formulas should refer to the basic formulas as follows;
The rubber main rubber zinc oxide stearyl ester anti-aging agent accelerator sulfur carbon black magnesium oxide carbon black specific surface area research is very important. The detection data of carbon black specific surface area is only true and reliable when the results are detected by BET method. Many instruments can only be tested by the direct comparison method, which is now being eliminated in China. At present, the multi-point BET method is used uniformly for the specific surface area testing at home and abroad. The specific surface area measurement standards developed at home and abroad are based on the BET test method. Please refer to China's national standard (GB / T 19587-2004)-Gas adsorption BET principle Method for determining the specific surface area of ​​solid materials. The measurement of specific surface area is actually a time-consuming task. Due to the different adsorption capacity of the sample, the test of some samples may take a whole day. If the test process is not fully automated, then the tester ca n’t leave at all times. A high degree of concentration, observing the instrument panel, manipulating the knob, and a little inattention will lead to the failure of the test process, which will waste a lot of precious time of the tester. The F-Sorb 2400 specific surface area analyzer of Beijing Jine Spectrum Technology Co., Ltd. is an instrument that can truly realize the detection function of the BET method (with direct comparison method), and the more important F-Sorb 2400 specific surface area of ​​Beijing Jin Ai Spectrum Technology Co., Ltd. The analyzer is the only fully automated intelligent specific surface area detection device in China so far. Its test results are highly consistent with international standards and its stability is also very good. At the same time, it reduces human errors and improves the accuracy of test results.
1. NR (natural rubber) 100 5 2 (PBN 1) (DM 1) 2.5
2 SBR (Styrene Butadiene Rosin) 100 3 1 (NS 1) 1.75 (Furnace Method 50)
3. CR (chloroprene) 100 5 0.5 (D2) (NA-22 0.35) (SRF29) 4
4. IIR (butyl) 100 5 3 TMTD 1 1.75 (HAF50)
5. NBR (Ding Jing) 100 5 1 DM 1 1.5 (gas 40)
6. BR (cis-butadiene) 100 3 2 (103 oil 15) NS0.9 1.5 (HAF60)
7. IR (Isopentyl) 100 5 2 NS0.7 2.25 (HAF35)
8. EPDM (EPDM) 100 5 1 (Naphthenic oil 15) M0.5TMTD1.5 1.5 (HAF50)
9. CSM (chlorosulfonated polyethylene) 100 black SRK40 lead monoxide 25DM0.5DPPT 2 white magnesium oxide 4DPPT2 pentaerythritol 3
10. CIIR (chlorinated butyl) 100 3 1 DM2TMTD1 (HAF50) 2
11. PSR (Polysulfur) 100 10 0.5 DM0.3DPD0.1 (SRK60)
12. ACM (acrylate) 100 FEF60 potassium stearyl 0.75 anti-RD1 sodium stearate 1.75 sulfur 0.25
13. PUR (polyurethane) 100 Gumaron 15M1 DM4 accelerator Caytur4 0.35 sulfur 0.75 cadmium stearate 0.5HAF30
14. CO (chlorohydrin) 100 lead stearate 2 FEF30 lead lead 1.5 anti-aging agent NBC2 accelerator NA-22 1.2
15. FKM (fluoroelastomer) 100 mesothermal cracking point ((MT) 20 magnesium oxide 15 vulcanizing agent Diak3 * 3.0.
16. Q (silicone rubber) 100 vulcanizing agent BOP, gas phase method, structure control agent.
3. The exchange relationship of accelerators,
DM 1 ==》 CZ 0.5-0.61
DM 1 ==》 M 0.52-0.8
DM 1 ==》 NOBS 0.63-0.69
DM 1 ==》 TMTD 0.08-0.10
NOBS 1 ==》 DM 1.43-1.6
NOBS 1 ==》 TMTD 0.1
NOBS 1 ==》 M 0.7-0.75
CZ 1 ==》 NOBS 1.2-1.3
Rubber is divided into natural rubber and synthetic rubber. Natural rubber is mainly derived from the three-leaf rubber tree. When the skin of this rubber tree is cut, milky white juice will flow out, called latex. The latex is obtained by coagulation, washing, molding and drying. Synthetic rubber is made by artificial synthesis methods, and different types of rubber can be synthesized using different raw materials (monomers).
General-purpose rubber refers to a type of rubber that partially or completely replaces natural rubber, such as styrene-butadiene rubber, cis-butadiene rubber, isoprene rubber, etc. It is mainly used to manufacture tires and general industrial rubber products. The demand for general rubber is large, and it is the main variety of synthetic rubber.
Styrene-butadiene rubber SBR is made from the copolymerization of butadiene and styrene. It is the largest general-purpose synthetic rubber, including emulsion polystyrene-butadiene rubber, solution polystyrene-butadiene rubber and thermoplastic rubber (SBS).
Butadiene rubber is made by solution polymerization of butadiene, butadiene rubber has particularly excellent cold resistance, wear resistance and elasticity, and also has good aging resistance. Most of cis-butadiene rubber is used to produce tires, and a small part is used to manufacture cold-resistant products, cushioning materials, tapes, rubber shoes, etc. The disadvantage of butadiene rubber is that the tear resistance is cross, and the wet skid resistance is not good.
Isoprene rubber is the abbreviation of polyisoprene rubber, produced by solution polymerization method. Isoprene rubber, like natural rubber, has good elasticity and wear resistance, excellent heat resistance and good chemical stability. The strength of isoprene raw rubber (before processing) is significantly lower than that of natural rubber, but the quality uniformity and processing performance are superior to natural rubber. Isoprene rubber can replace natural rubber for truck tires and off-road tires and can also be used to produce various rubber products.
Ethylene-propylene rubber Ethylene-propylene rubber is synthesized with ethylene and propylene as the main raw materials, and has outstanding resistance to aging, electrical insulation and ozone. Ethylene-propylene rubber can be filled with oil and carbon black in a large amount. The price of the product is low. The chemical stability of ethylene-propylene rubber is good. The wear resistance, elasticity, and oil resistance are close to those of styrene-butadiene rubber. Ethylene-propylene rubber is very versatile. It can be used as tire sidewalls, rubber strips, inner tubes, and auto parts. It can also be used as wires, cable sheaths, and high-voltage and ultra-high-voltage insulation materials. It can also manufacture light-colored products such as rubber shoes and hygiene products.
Neoprene is made of chloroprene as the main raw material, through homopolymerization or copolymerization of a small amount of other monomers. Such as high tensile strength, excellent heat resistance, light resistance, aging resistance, oil resistance are better than natural rubber, styrene-butadiene rubber, butadiene rubber. It has strong flame resistance and excellent flame retardancy, its chemical stability is high, and its water resistance is good. The disadvantage of neoprene is electrical insulation performance, poor cold resistance, and raw rubber is unstable during storage. Neoprene has a wide range of uses, such as the production of transport belts and transmission belts, the covering materials of wires and cables, the manufacture of oil-resistant hoses, gaskets, and chemical-resistant equipment linings.
Rubber (Rubber): highly elastic polymer material with reversible deformation. It is flexible at room temperature, and can produce large deformation under the action of a small external force, and can be restored to its original state after removing the external force. Rubber is a completely amorphous polymer. Its glass transition temperature (T g) is low, and its molecular weight is often very large, more than hundreds of thousands.
The word rubber comes from the Indian language cau-uchu, which means "a tree weeping". Natural rubber is produced by solidifying and drying the latex that flows out when the trifoliate rubber tree is tapped. In 1770, British chemist J. Priestley discovered that rubber can be used to erase pencil writing. At that time, the material used for this purpose was called rubber, and the term has been used to this day. The molecular chain of rubber can be cross-linked. When the cross-linked rubber is deformed by external force, it has the ability of rapid recovery, and has good physical and mechanical properties and chemical stability. Rubber is the basic raw material of the rubber industry and is widely used in the manufacture of tires, hoses, tapes, cables and other various rubber products.
Types of rubber are divided into natural rubber and synthetic rubber according to raw materials. According to the shape, it can be divided into block raw rubber, latex, liquid rubber and powder rubber. Latex is a colloidal water dispersion of rubber; liquid rubber is an oligomer of rubber, which is generally a viscous liquid before being vulcanized; powdered rubber is processed into powder form by latex to facilitate ingredients and processing. The thermoplastic rubber developed in the 1960s did not require chemical vulcanization, but was formed using thermoplastic processing methods. Rubber is divided into general type and special type according to the use.
Structure Linear structure: The general structure of unvulcanized rubber. Due to its large molecular weight, it appears as a fine mass without external force. When the external force acts and the external force is removed, the entanglement of the fine mass changes, and the molecular chain rebounds, resulting in a strong tendency to recover. This is the origin of the high elasticity of rubber.
Branched structure: the aggregation of the branches of the rubber macromolecular chain to form a gel. Gels are detrimental to the performance and processing of rubber. When mixing rubber, various compounding agents often improve the gel area, forming partial voids, which cannot form reinforcement and cross-linking, and become weak parts of the product.
Cross-linked structure: Linear molecules are connected to each other through the bridging of some atoms or atomic groups to form a three-dimensional network structure. As the vulcanization process progresses, this structure continues to strengthen. In this way, the free mobility of the segment decreases, the plasticity and elongation decrease, the strength, elasticity and hardness increase, the compression permanent deformation and the degree of swelling decrease.
The general performance of the rubber for use is good, and it is widely used. The main are: â‘ natural rubber. Made from the latex of the Hevea tree, the basic chemical composition is cis-polyisoprene. Good elasticity, high strength and good comprehensive performance. â‘¡ Isoprene rubber. The full name is cis-1,4-polyisoprene rubber. The high cis synthetic rubber made from isoprene is also called synthetic natural rubber because its structure and performance are similar to natural rubber. â‘¢ SBR. Referred to as SBR, it is made by copolymerization of butadiene and styrene. According to the production method, it is divided into emulsion polymerized SBR and solution polymerized SBR. Its comprehensive performance and chemical stability are good. â‘£ Butadiene rubber. The full name is cis-1,4-polybutadiene rubber, abbreviated as BR, which is made by polymerization of butadiene. Compared with other general-purpose rubbers, vulcanized butadiene rubber is particularly excellent in cold resistance, wear resistance and elasticity, less heat under dynamic load, good aging resistance, easy to use with natural rubber, neoprene, nitrile rubber .
Special rubber refers to rubber with some special properties. The main are: ①neoprene. Referred to as CR, it is made by the polymerization of chloroprene. Has good comprehensive performance, oil resistance, flame resistance, oxidation resistance and ozone resistance. However, its density is large, it is easy to crystallize and harden at normal temperature, the storage is not good, and the cold resistance is poor. ② Nitrile rubber. Referred to as NBR, it is made by copolymerization of butadiene and acrylonitrile. Good oil resistance and aging resistance, can be used for a long time in the air at 120 ℃ or in the oil at 150 ℃. In addition, it also has water resistance, air tightness and excellent bonding properties. ③ Silicone rubber. The main chain consists of alternating silicon and oxygen atoms, with organic groups on the silicon atoms. High and low temperature resistance, ozone resistance, good electrical insulation. ④ Fluorine rubber. Synthetic rubber containing fluorine atoms in the molecular structure. It is usually expressed in terms of the number of fluorine atoms in the fluorine-containing units in the copolymer. For example, fluororubber 23 is a copolymer of vinylidene fluoride and chlorotrifluoroethylene. Fluorine rubber is resistant to high temperature, oil, and chemical corrosion. ⑤Polysulfide rubber. It is formed by polycondensation of polyhalides of dihaloalkanes and alkali metals or alkaline earth metals. It has excellent oil resistance and solvent resistance, but the strength is not high, the aging resistance and processability are not good, and it has an odor. It is often used together with nitrile rubber. In addition, there are polyurethane rubber, chlorohydrin rubber, acrylic rubber and so on.
Rubber processing
This process includes basic processes such as plasticizing, kneading, calendering or extrusion, molding, and vulcanization. Each process has different requirements for products and is accompanied by several auxiliary operations. In order to add various required compounding agents to the rubber, the raw rubber first needs to be plasticized to improve its plasticity; then the carbon black and various rubber additives and rubber are evenly mixed into the rubber compound by mixing; the rubber compound is pressed It is made into a blank with a certain shape; it is then combined with textile materials (or metal materials) that have been calendered or glued to form a semi-finished product; finally, the semi-finished product with plasticity is made into a highly elastic final product after vulcanization. .
Specification of natural rubber
Natural rubber can be divided into standard glue (also known as granular glue), smoke film, concentrated glue, white crepe film, light-colored film, gelatin rubber and air-drying film, etc. The most commonly used are standard glue and smoke film. Standard glue is divided into four grades of first grade (SCR5), second grade (SCR10), third grade (SCR20), and fourth grade (SCR50), and the smoke glue is divided into five grades of No. 1 ~ 5 smoke film (RSS1 ~ RSS5).
Standard glue: Standard rubber is mainly divided into No. 5 glue, No. 10 glue and No. 20 glue. No. 5 glue is the first grade glue, which is the best glue, and its impurities are 0.05%; No. 10 glue is the second grade glue. The impurities contained in it are 0.10%; the No. 20 glue is a tertiary glue, and the contained impurities are 0.20%. The use of different types of glue is also different: No. 5 glue is generally used to make tire inner tubes; No. 10 glue and No. 20 glue Generally used to make tire casings.
Smoke film: It is the film obtained after the smoke and heat generated by burning the coconut shell are used to smoke the natural film that has been dehydrated. The purpose of smoking is to dry the film and inject anti-oxidation and anti-corrosion cresol substances. Cigarette film belongs to the primary shape of natural rubber concentrate: it can be used as a bonding material.
Crepe film:
The delivery of the special first-class thin white crepe film must be extremely white and uniform, dry and firm rubber.
Discoloration, sour odor, dust, crumbs, grit or other foreign substances, oil or other stains, signs of oxidation or overheating caused by any cause are not allowed.
The delivery of the first-grade thin white crepe film must be white, dry and firm rubber. Very slight differences in shades of color are allowed.
Discoloration, sour odor, dust, crumbs, grit or other foreign substances, oil or other stains, signs of oxidation or overheating caused by any cause are not allowed.
The delivery of the special first-class thin and light-colored crepe film must be light, uniform, dry and firm rubber.
Discoloration, sour odor, dust, crumbs, grit or other foreign substances, oil or other stains, signs of oxidation or overheating caused by any cause are not allowed.
The delivery of the first-grade thin and light-colored crepe film must be light, dry and solid rubber. Very slight differences in shades of color are allowed.
Discoloration, sour odor, dust, crumbs, grit or other foreign substances, oil or other stains, signs of oxidation or overheating caused by any cause are not allowed.
The delivery of the second-level thin and light-colored crepe film must be dry, firm rubber. The color is slightly darker than the first-class thin light crepe film. Allow slight differences in shades of color.
Rubber with marks and streaks to the extent shown in the sample is allowed. However, in the inspected plastic bags, the number of such plastic bags shall not exceed 10% of the number of inspected plastic bags.
Except for those permitted above, no discoloration, dust, debris, grit or other foreign substances, oil or other stains, signs of oxidation or overheating caused by any cause are allowed.
The delivery of the third-grade thin and light-colored crepe film must be light yellow, dry and firm rubber. Allow differences in shades of color.
Rubber with marks and streaks to the extent shown in the sample is allowed. However, in the inspected plastic bags, the number of such plastic bags shall not exceed 20% of the number of inspected plastic bags.
Common advantages and disadvantages of rubber materials
Natural rubber NR
(Natural Rubber) It is made of rubber tree latex and is a polymer of isoprene. It has good wear resistance, high elasticity, tear strength and elongation. It is easy to age in the air and changes in heat Sticky, easy to swell and dissolve in mineral oil or gasoline, resistant to alkali but not strong acid. Advantages: good elasticity, acid and alkali resistance. Disadvantages: Not weather resistant and oil resistant (vegetable oil resistant) is the raw material for making tape, hoses, and rubber shoes, and is suitable for making shock-absorbing parts, products used in hydroxide-containing liquids such as automobile brake oil, ethanol, etc.
SBR
(Styrene Butadiene Copolyme) Copolymer of butadiene and styrene. Compared with natural rubber, it has uniform quality and less foreign matter. It has better wear resistance and aging resistance, but its mechanical strength is weaker. It can be blended with natural rubber Combined use. Advantages: Low-cost non-oil-resistant material, good water resistance, good elasticity below hardness 70, poor compressibility at high hardness, disadvantages: It is not recommended to use strong acids, ozone, oils, oil esters and fats and large Part of the hydrocarbons. Widely used in tire industry, shoe industry, cloth industry and conveyor belt industry.
Butyl rubber IIR
(Butyl Rubber) is formed by the polymerization of isobutylene and a small amount of isoprene. Because the movement of steric barrier molecules of methyl group is less than other polymers, the gas permeability is less and the resistance to heat, sunlight and ozone is greater. Good electrical insulation; high resistance to polar agents, general operating temperature range is -54-110 ℃. Advantages: impermeable to most general gases, good resistance to sunlight and odor can be exposed to Animal or vegetable oils or vaporizable chemicals. Disadvantages: It is not recommended to use inner tubes, leather bags, rubber paste paper, window frame rubber, steam hoses, heat-resistant conveyor belts, etc. for car tires together with petroleum solvents, kerosene and aromatic hydrogen.
HNBR
(Hydrogenate Nitrile) Hydrogenated nitrile butadiene rubber is partially removed by hydrogenation in nitrile rubber. After hydrogenation, its temperature resistance and weather resistance are much higher than that of ordinary nitrile rubber, and its oil resistance is similar to that of ordinary nitrile rubber. The general temperature range is -25 ~ 150 ℃. Advantages: better wear resistance than nitrile rubber, with excellent corrosion resistance, tensile resistance, tear resistance and compression characteristics
It has good resistance under atmospheric conditions such as ozone, and is generally suitable for cleaning agents for washing or washing dishes. Disadvantages: Not recommended for use in alcohols, esters or aromatic solutions in the air-conditioning and refrigeration industry. It is widely used as a seal in the environmentally friendly refrigerant R134a system.
Automotive engine system seals.
Ethylene propylene rubber (EPDM) is made from the copolymerization of ethylene and propylene, so it has excellent heat resistance, aging resistance, ozone resistance, and stability, but it cannot be vulcanized. To solve this problem, in EP Introduce a small amount of the third component of the double chain into the main chain and add sulfur to form EPDM. The general use temperature is -50 ~ 150 ℃. Excellent resistance to polar solvents such as alcohol and ketone. Advantages: Good weather resistance And ozone resistance, with excellent water resistance and chemical resistance, can use alcohols and ketones, high temperature vapor resistance, good impermeability to gas. Disadvantages: Not recommended for food use or exposure to aromatic hydrogen. Seals or parts for sanitary equipment in high temperature water vapor environment. Rubber parts in the braking (braking) system. Seals in radiators (car water tanks).
NBR
(Nitrile Rubber) It is made by the copolymerization of acrylonitrile and butadiene. The content of acrylonitrile is from 18% to 50%. Deterioration, the general operating temperature range is -25 ~ 100 ℃. NBR is one of the most commonly used rubbers for oil seals and O-rings at present: it has good oil resistance, water resistance, solvent resistance and high pressure oil characteristics
With good compressibility, wear resistance and elongation.
Disadvantages: Not suitable for use in polar solvents, such as ketones, ozone, nitro hydrocarbons, MEK and chloroform.? Used for making fuel tanks, lubricating oil tanks and in petroleum-based hydraulic oil, gasoline, water, silicone oil, diesters It is a rubber part used in fluid media such as lubricating oil, especially a sealing part. It can be said that it is the most widely used and lowest cost rubber seal at present
Neoprene CR
(Neoprene, Polychloroprene) It is made of chloroprene monomer. The vulcanized rubber has good abrasion resistance, is not afraid of direct sunlight, has particularly good weather resistance, is not afraid of intense distortion, is not afraid of refrigerant, and is resistant to thinning Acid and silicon ester-based lubricating oil, but not phosphate-based hydraulic oil. It is easy to crystallize and harden at low temperature, and has poor storage stability. It has a large expansion in mineral oil with a low aniline point. The general use temperature range is -50 ~ 150 ℃. Advantages: good elasticity and good compression deformation, the formula does not contain sulfur so it is very easy to make. It has the characteristics of anti-animal and vegetable oils, will not be caused by neutral chemicals, fats, greases, various oils, Solvent affects physical properties and has flameproof properties
Disadvantages: It is not recommended to use R12 refrigerant resistant seals, rubber parts or seals on household appliances among chemicals of strong acids, nitro hydrocarbons, esters, chloroform and ketones. It is suitable for making all kinds of parts directly exposed to the atmosphere, sunlight and ozone. It is suitable for all kinds of rubber products that are resistant to fire and chemicals.
Composition of Synthetic Rubber Synthetic rubber is a polymer made from petroleum and natural gas as raw materials, and diene and olefin as monomers.
The polymer of rubber has broken through the process of monomer polymerization.At present, the world's leading rubber factories have begun to use stronger rubber, which is made of ultra-high polymer aggregates, and the cost is quite low.