Rubber fertilizer application in synthetic rubber profiles

Wang Jingtong, stven (Beijing rubber industry research and design institute, Beijing 100143)

Abstract: the article introduces vulcanizing agent, promoter and surfactant additives such as vulcanization system, antioxidants, physical and chemical stabilizer of the stabilizer additives such as protection system, tackifier and plasticizer, homogenizing agent and the characteristics of dispersant and other processing AIDS and its application in synthetic rubber profiles. Synthetic rubber with a rubber additives to environmental protection, high efficiency, multi-function, low cost direction.

Key words: rubber additives; Synthetic rubber; Vulcanization system AIDS; Protective system AIDS; Processing AIDS

Vulcanization system additives, protective system additives, processing AIDS, plays an important role in the synthetic rubber formulation, are the main factors influencing the performance of rubber products. This paper mainly introduces the categories of rubber additives in the application of synthetic rubber profiles.

1 · additives vulcanization system

Vulcanization system of fertilizer is mainly composed of vulcanizing agent, promoter and surfactant, its consumption accounts for about 10% of the raw rubber consumption [1]. According to the saturation of synthetic rubber, can use sulfur, metal oxide, peroxide and amine compounds, such as a variety of vulcanization system.

1.1 vulcanizing agent

According to analysing and performance requirements of different rubber products, can use sulfur oxime, peroxide, quinone, resin, metal oxide vulcanization system. Among them, the sulfur curing system is divided into ordinary vulcanization system and efficient vulcanization system and efficient vulcanization system and so on.

Sulfur curing system in general synthetic rubber and half use the more general synthetic rubber, metal oxide vulcanization system is mainly used for neoprene (CR), quinone oxime and resin curing system is mainly used for butyl rubber (IIR), peroxides and resin curing system is mainly used for ethylene propylene rubber (EPR), natural rubber (NR) and styrene-butadiene rubber (SBR). Special rubber [such as thiokol (LP), chlorosulfonated polyethylene rubber (CSM), chlorinated polyethylene rubber (CM) (F K M), silicone rubber, fluorine rubber (M V (Q), fluorine silicone rubber (FVMQ)] basic belong to saturated rubber, do not contain a double bond, the can't afford to the crosslinking effect on sulfur, so need to adopt the sulfur curing system, such as metal oxide, peroxide, organic amine salt vulcanization system, etc. Acrylate rubber (ACM) in recent years has been largely with sulfur curing system.

(1) sulfur. Ordinary powder sulfur vulcanizing agent is the most commonly used rubber industry. Along with the development of meridian tyre and color rubber products, do not spray frost, do not affect the adhesive performance and product appearance of insoluble sulfur (IS) widely used. IS most used in NR rubber tires, have improve - skeleton materials rubber adhesive performance, avoid spray frost, extend the storage time, rubber IS in butadiene rubber (BR) in the tire stock also has a small amount of application.

(2) peroxide [2]. In addition to the I I R and halogenated butyl rubber (XIIR), the rest especially MVQ and EPDM rubber (EPDM), nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), CM, CR and thermoplastic elastomer, almost can use peroxide vulcanization. Peroxide vulcanized rubber crosslinking key is C - C key, the key can than single sulfur sulfur vulcanization rubber keys, double sulfur and sulfur more keys keys can be big, therefore peroxide vulcanized rubber hot oxygen aging performance, compression permanent deformation is small, difficult to bloom, no sulfide to return the original phenomenon, but its tensile properties, strain and fatigue resistance performance is poorer.

(3) resin. To improve the heat resistance and aging resistance of the rubber, many analysing (IIR, NR, SBR and NBR, etc.) has been widely used resin (such as alkyl phenolic resin, etc.) as crosslinking agent. Resin curing of IIR rubber heat resistant performance is good, compression permanent deformation is small, has become the main rubber vulcanization capsule. Resin as IIR vulcanizing agent, vulcanizing speed is slow, and the curing temperature is high. Phenolic resin curing system is often used in EPDM/PP, and other rubber and plastic blending material preparation.

(4) metal oxide. Such as CR, CM and XIIR containing halogen or containing carboxyl rubber using metal oxide as curing agent. Common metal oxide as the zinc oxide and magnesium oxide, activated zinc oxide and light magnesium oxide is the best.

(5) sulfur donor. Sulfur donor is in rubber vulcanization process can decompose the sulfur vulcanization agent. The characteristics of the rubber is heat resistant performance is better than sulfur cement material, at the same time compression deformation resistance is excellent, and scorch resistant performance is good, is not easy to bloom. But for most of the sulfur donor toxic and added to the list of ranks, restrict the use of such as vulcanizing agent containing morpholine base DTDM and TMTD.

(6) amine compounds. FKM and ACM often use amine compounds as vulcanizing agent, mainly has methylene amine, aniline compounds, etc.

1.2 promoter

Promoters including thiazole sulfonamide, times, thiuram, guanidine and disulfide carbamate salts. With the constant deepening of environmental awareness and improve, a variety of promoter due to toxic, polluting, has become the restrictions on the use of objects.

Times sulfonamide classes alternative varieties mainly to promote the agent of the accelerator TBBS (NS), TBSI, CBBS and CBS (CZ), etc. Thiuram class replace main varieties of the accelerator to promote the agent TBzTD, etc.; Dithiocarbamate salts promoter alternative varieties mainly for accelerator ZBEC (DBZ), etc.; Promoter DTDM and OTOS alternative varieties mainly Duralink HTS and Perkalink - 900.

At present, the commonly used promoter varieties for accelerator TBBS and CBS, the dosage of promoter in China more than 36% of the total amount; Accelerator MBT, MBTS (DM), the amount of the 4 kinds of accelerator TBBS and CBS accounts for over 70% of the total amount of accelerator in China.

Promoter TBzTD scorch time is long, the processing safety, alternative accelerator TMTD and TETD thiuram promoter. In rubber accelerator TBSI have longer scorch time and slow down the characteristics of the curing rate, can obviously increase the sulfide to return the original resistance of NR. Promoter ZBEC as NR, SBR, EPDM, natural rubber latex and synthetic latex main promoter or help promote agent, has the very good scorch resistance. Diphenyl guanidine class DPG accelerator (D) is mainly used as natural rubber and synthetic rubber accelerator, added in the high white carbon black filled rubber DPG accelerator, can obviously reduce the Mooney viscosity of mixing rubber, can also improve the curing rate.

1.3 active agent

Surfactant is to improve the promoter activity, promote the vulcanization reaction system of sulfide additives, so it is also known as promoting agent or vulcanization agent. Surfactant is much by metal oxide and fatty acid composition, the most typical of the indirect method zinc oxide (3 ~ 5) combined with stearic acid (1 ~ 2). Rubber products in the production, use and recycling of excess release of zinc oxide, may to the environment and human health, especially for zinc is more sensitive to adverse impact on aquatic plants and animals. At present to develop the low zinc or zinc sulfide surfactant (such as organic zinc, zinc oxide masterbatch, calcium oxide and magnesium oxide, etc.) to partly replace zinc oxide. Studies have shown that organic zinc and zinc oxide core-shell structure can vulcanizing agent role, but the resistance of the rubber vulcanization back to the original performance and physical properties are less than the indirect method zinc oxide adhesive material.

2 · protective system for auxiliary

Rubber in use process prone to aging, need to add protective system of ageing could he slowed down, avoid the rapid decline in performance. Physical stabilizer for light screening agent or wax, chemical stabilizer including amines, phenols, esters and other compounds. Synthetic rubber to join a small amount of antioxidants in the process of synthesis, and the back to join a large number of stabilizer in the processing course.

2.1 with synthetic rubber antioxidant

Synthetic rubber in antioxidants to join the process according to the synthetic technology and product color to choose. Need to select soluble in soluble poly rubber rubber synthetic antioxidants of the solvent used, emulsion poly rubber to choose can form a stable emulsion with emulsifier used in the synthetic rubber antioxidant, moreover, according to the color of the product choose polluting or non polluting antioxidants. Polybutadiene rubber (BR), styrene thermoplastic elastomer, isoprene rubber (IR), and other soluble poly rubber before using antioxidant butylated hydroxytoluene (264), sometimes class with phosphite ester antioxidant TNP (TNPP). Antioxidant TNP easy to hydrolysis, because produce nonylphenol affect biological reproductive health and are prohibited from use. Antioxidant butylated hydroxytoluene relative molecular mass is small, easy to volatilize, abroad study think that the more volatile harmful to the environment, so it more than other phenolic antioxidants in alternative, more common with antioxidant 1076 and 1076, or and auxiliary antioxidants to create synergies. Light color milk polyethylene rubber styrene with phenolic antioxidants phenol, dark rubber used more polluting amine antioxidants. Synthetic rubber antioxidant is environmental protection, large molecular weight, distribution and multifunctional direction. By DSC method to detect raw rubber of oxidation induction period or induced oxidation temperature, can also through the heat oxygen aging resistance to inspect the performance of the antioxidants. Light color rubber products also need to examine hot oxygen aging resistance and yellowing resistance.

2.2 protective agent

2.2.1 physical stabilizer

Synthetic rubber rubber use paraffin as more resistance to ozone and weather aging physical stabilizer. Rubber vulcanization when the dissolved after cooling gradually migrate to the surface of rubber, paraffin wax forming a dense and flexible layer of wax membrane, isolating the ozone in the air, play a protective role. Compared with normal protective wax, has a variety of functional groups of the modified wax molecular structure (such as carboxyl, hydroxyl, etc.). Modified wax protection 1.5 ~ 3 times higher than normal protective wax. Using modified wax reduces the consumption of the antiozonant.

2.2.2 chemical stabilizer

Application of stabilizer in the process of synthetic rubber processing mainly amine and quinoline stabilizer. Common varieties is antiager 4020401 0 NA and RD. At present, the three kinds of stabilizer dosage of stabilizer dosage of more than 80%.

Naphthalene amine stabilizer has A lot of, such as phenyl - alpha - naphthylamine (antiager A), 1 - phenyl - beta - naphthylamine (antiager D). But due to its toxicity and carcinogenicity problems, all countries in the 1970 s began to slash its production until now disabled.

Antiager RD in China has become one of the main protective agent of meridian tire stock, the product of the effective components of 2 - methyl - 1, 2, 4-trichlorobenzene of three hydrogenation of quinoline two, three, four polymers, especially dimers anti aging performance is very good, so the dimer content should be increased. Antiager RD heat oxygen aging performance excellence with copper and other metal ions have a stronger inhibitory effect, but poor resistance to ozone and flexible performance, with the protective agent AW or para-phenylene diamine stabilizer (antiager 4020), etc. Antiager AW can prevent rubber products caused by ozone cracking, especially suitable for use under the condition of dynamic of rubber products, rubber and antiager H, D and 4010 etc, can enhance its efficiency.

Para-phenylene diamine class stabilizer based on para-phenylene diamine even group is divided into dialkyl para-phenylene diamine, diaryl to phenylenediamine and alkyl aryl para-phenylene diamine class. Two alkyl benzene 2 amine stabilizer main varieties such as protective agent 4030 and 288. Antiager 4030 easy to disperse in rubber solubility is bigger, no crocking problem, large dosage of mixing rubber a shorter scorch time and accelerate vulcanization role; Excellent results for static ozone aging protection, ozone aging resistance is obviously better than the excellent antiager 4010 na and 4020, especially suitable for long-term static under the condition of wire and cable, rubber hose, adhesive tape and other outdoor use rubber rubber. Alkyl aryl para-phenylene diamine class the main varieties have antiager 4010401 0 NA, antiager 4020 and H, etc. Antiager 4020 varieties of tire rubber consumption is the largest stabilizer, the aging of the ozone aging and flexible crack has good protective effect, the aging of the hot oxygen aging and weather also has a good protective effect, and the base metal have passivation effect, suitable for NR, BR, SBR, NBR, and CR, and paraffin (especially with a mixture of branched chain wax and microcrystalline wax) and use, can enhance the static protection. Compared with the antiager 4010 na, antiager 4020 water extraction resistance is good, can achieve the result of long-term protection.

Diaryl para-phenylene diamine class antiager main varieties antiager 3100 and H, etc. Antiager 3100 characteristic is not out, no stimulation to skin, tires and other rubber products of ozone, oxygen and flexible fatigue aging have very good protection effect, especially suitable for the conditions of use harsh truck tyre and off-road tires, rubber and effects of the CR antiozonant. Stabilizer on the benzene ring on both sides of the molecular structure of 3100 introduced a one or two genes, their capacities increase its solubility in the rubber, can increase the dosage in the rubber, can eliminate application antiager 4010 na and 4020 rubber red defects, particularly good protection of harmful metals such as copper, manganese, Defect is rubber by light to dark brown, severe pollution at the same time, it will only apply to brunet products rubber.

Rubber stabilizer in recent years, new development and application of less, and with the requirements of environmental protection is more and more strict, antiager gradually to the direction of high-performance and environmental protection and development of rubber stabilizer species gradually tend to be concentrated, future dosage biggest antiager RD and 4020 species.

3, processing AIDS

Rubber processing aid for rubber physical role only, and not cause chemical reaction.

3.1 tackifier viscosifier is used to increase the self-adhesive rubber processing aid. Rubber self-adhesive can affect the package of the rubber roller, which affect the strength of the compound dispersion, rubber and extrusion process continuity and the bubble. The proper viscosity and conducive to improve the stiffness of rubber.

Our common tackifier mainly octyl phenolic resin (203 resin), tertiary butyl phenolic resin (204 resin) and acetylene para-tertiary butyl phenol resin (Koresin resin), etc. Modified tert butyl phenolic resin (HY - 2006 resin) is a kind of modified products, based on 204 resin has better adhesive performance and wet and heat aging resistance, alternative Koresin resin. Saturated rubber viscosity resin HY - 209 is designed for EPDM development tackifier.

3.2 plasticizer

Plasticizer can improve polymer processing performance, increase its flexibility and tensile properties of processing AIDS. According to its mechanism can be divided into two categories, chemical and physical plasticizer plasticizer. Traditionally called physical plasticizer softener, chemical agent plasticizer called plastic solution. Main synthetic rubber with physical plasticizer. Radial tyre after mass production, plasticizer A widely application in China. It can dissolve in rubber evenly, make packing with quickly, shortening the time of rubber mixing, plasticizing effect is obvious.

Oil system operating oil is another commonly used physical plasticizer in rubber processing. High aromatic oil because of polycyclic aromatic hydrocarbons carcinogenic risk was banned in the European Union.

3.3 homogenizing agent

Homogenizing agent's main function is to solve different polarity and viscosity of polymer blend. Homogenizing agent used in air barrier and vulcanization capsule, as the radial tyre structure improvement, the amount of brominated butyl rubber (BIIR) will be more and more big, added a lot of difficulties for the rubber processing, such as vulcanized rubber and unvulcanized rubber adhesive force is small, rolling process of gas entrapment phenomenon, etc. At present in air barrier gel mainly use imported TNB88 homogenizing agent, UB4000 and 40 MSF. By homogenizing agent 40 ms (F) in whole or in part to replace oil can improve the operation of rubber processing and safety performance, flexible resistance, adhesion properties and heat aging properties. Homogenizing agent used in the tread compound can play the lubrication, reduce the rubber Mooney viscosity, improve the tire wear resistance; Improve extrusion speed, reduce rubber extrusion temperature, reduce extrusion tread broken edge and pores, reduce the processing cost.

3.4 dispersant

Dispersant's main function is to improve the rubber carbon black and other additives in diffuse. Dispersing agent in rubber mixing process plays a role of lubrication in general, can reduce the internal friction between rubber macromolecule chain, reduce mixing adhesive capacity, promote carbon black and other scattered chelating agent, to improve the homogeneity of rubber and processing performance, the mixing time and the energy consumption decreased, speed up the filler dispersion. With the continuous development of tire industry, is gradually increasing dosage of synthetic rubber, carbon black dosage, all of these factors to inconvenience rubber processing, so the application of the dispersant become inevitable. Material with dispersion effect is a fatty acid, fatty acid metal salt, fatty acid ester, fatty acid and fatty acid ester polymer condensation products and its mixture with metal soap.

4 · conclusion

With the development of rubber industry, synthetic rubber consumption increased year by year. Rubber additives in the development and application in China in recent years has made great progress, but there are a lot of shortcomings. Rubber additives to environmental protection, high efficiency, multi-function, low cost direction, rubber fertilizer production enterprises should strengthen the research and application in synthetic rubber keep up with the pace of the rapid development of rubber industry.