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US-12624198-B2 - Rubber composition, processing method thereof, and rubber product using the same

US12624198B2US 12624198 B2US12624198 B2US 12624198B2US-12624198-B2

Abstract

The present invention discloses a rubber composition, a processing method thereof, and rubber product reinforced with silica using the same. The rubber composition comprises a rubber matrix and essential components, wherein, based on 100 parts by weight of the rubber matrix, the rubber matrix comprises, a branched polyethylene with a content represented as A, in which 0<A≤100, and an EPM and an EPDM with a total content represented as B, in which 0≤B<100; and the essential components comprise 1-10 parts of a crosslinking agent and 15-80 parts of silica. The rubber composition can be used for producing high-voltage insulating sheath rubber, high-temperature resistant conveyor belt, waterproof coil, rubber particles for plastic track surface layer, rubber plug, rubber roller, inner tube, tire tread, tire sidewall, and inner rubber layer of air-conditioner hose.

Inventors

  • Tao Xu
  • Zhi Sheng FU
  • An Yang WU

Assignees

  • HANGZHOU XINGLU TECHNOLOGIES CO., LTD

Dates

Publication Date
20260512
Application Date
20180112
Priority Date
20170113

Claims (19)

  1. 1 . A rubber composition, comprising a rubber matrix and essential components, wherein, the rubber matrix comprises, based on 100 parts by weight of the rubber matrix, a branched polyethylene with a content represented as A, in which 0<A<100, and an EPM and an EPDM, with a total content represented as B, in which 0<B<100; wherein A+B is equal to 100 total parts; wherein, based on 100 parts by weight of the rubber matrix, the essential components comprise 1-10 parts of a crosslinking agent and 15-80 parts of silica, wherein, the branched polyethylene comprises a combination of a first ethylene homopolymer and a second ethylene homopolymer, wherein each ethylene homopolymer has: a degree of branching of not less than 50 branches/1000 carbon atoms, a weight average molecular weight of not less than 50,000, and a Mooney viscosity ML (1+4) at 125° C. of not less than 2.
  2. 2 . The rubber composition according to claim 1 , wherein, the crosslinking agent comprises at least one of a peroxide crosslinking agent and sulfur, and the peroxide crosslinking agent comprises at least one of di-tert-butyl peroxide, dicumyl peroxide, tert-butyl cumyl peroxide, 1,1-di-tert-butyl peroxide-3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di (tert-butylperoxy)hexane, 2,5-dimethyl-2,5-di (tert-butylperoxy)hexyne-3, bis (tert-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-bis (benzoylperoxy)hexane, tert-butyl peroxybenzoate, and tert-butylperoxy-2-ethylhexyl carbonate.
  3. 3 . The rubber composition according to claim 1 , wherein, based on 100 parts by weight of the rubber matrix, the essential components comprise 2-7 parts of a crosslinking agent and 30-60 parts of silica.
  4. 4 . The rubber composition according to claim 1 , wherein, the silica is at least one of precipitated silica and fumed silica, and the precipitated silica is high-dispersibility precipitated silica.
  5. 5 . The rubber composition according to claim 1 , wherein, the rubber composition further comprises auxiliary components, and based on 100 parts by weight of the rubber matrix, the auxiliary components comprise: 0.2-10 parts of an assistant crosslinking agent, 20-120 parts of an inorganic filler, 2-130 parts of a plasticizer, 1-3 parts of the stabilizer, 2-20 parts of metal oxide, 1-20 parts of a surface modifier, 1-10 parts of a coloring agent, 0-3 parts of a vulcanization accelerator, and 0-20 parts of a binder.
  6. 6 . The rubber composition according to claim 5 , wherein the assistant crosslinking agent comprises at least one of triallyl cyanurate, triallyl isocyanurate, ethylene dimethacrylate, ethyl dimethacrylate, triethylene dimethacrylate, triallyl trimellitate, trimethylolpropane trimethacrylate, ethylene dimethyacrylate, N,N′-m-phenylene bismaleimide, N,N′-bis(furfurylidene)acetone, 1,2-polybutadiene, a metal salt of unsaturated carboxylic acid, and sulfur; the plasticizing agent comprises at least one of pine tar, engine oil, naphthenic oil, paraffin oil, coumarone, stearic acid, and paraffin; the metal oxide comprises at least one of zinc oxide, magnesium oxide, and calcium oxide; the inorganic filler comprises at least one of calcium carbonate, talcum powder, calcined clay, magnesium silicate, magnesium carbonate, and barium sulfate; the surface modifier comprises at least one of polyethylene glycol having a molecular weight of 2000 or 3400 or 4000, diphenyl silicon glycol, triethanolamine, vinyl tris(2-methoxyethoxy)silane, 3-glycidoxypropyltrimethoxysilane, and γ-mercaptopropyltrimethoxysilane; the coloring agent comprises at least one of iron oxide red, titanium pigment, pigment blue, pigment green, and carbon black; the vulcanization accelerator comprises at least one of 2-mercaptobenzothiazole, dibenzothiazyl disulfide, tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, N-cyclohexyl-2-benzothiazolesulfenamide, N,N-dicyclohexyl-2-benzothiazolesulfenamide, bismaleimide, and ethylene thiourea; the binder comprises at least one of a resorcinol donor and a methylene donor.
  7. 7 . A tire, wherein, the rubber compound used for the sidewall of said tire or the rubber compound used for the tread of said tire comprises the rubber composition according to claim 1 .
  8. 8 . The rubber composition according to claim 1 , wherein: the branched polyethylene content A is from 30 to 80 parts by weight; the total content B of EPM and EPDM is from 20 to 70 parts by weight; the crosslinking agent is present in an amount of 3-5 parts by weight based on 100 parts by weight of the rubber matrix; and the silica is present in an amount of 35-45 parts by weight based on 100 parts by weight of the rubber matrix.
  9. 9 . The rubber composition according to claim 1 , wherein the essential components include a stabilizer, and wherein the stabilizer comprises at least one of 2,2,4-trimethyl-1,2-dihydroquinoline polymer, and 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline.
  10. 10 . The rubber composition according to claim 1 , wherein: the branched polyethylene content A is from 50 to 70 parts by weight; the total content B of EPM and EPDM is from 30 to 50 parts by weight; the EPM is present in an amount of 10-30 parts by weight; and the EPDM is present in an amount of 20-40 parts by weight.
  11. 11 . The rubber composition according to claim 1 , wherein: the first ethylene homopolymer comprises 60-80% by weight of the total branched polyethylene; and the second ethylene homopolymer comprises 20-40% by weight of the total branched polyethylene.
  12. 12 . The rubber composition according to claim 11 , wherein: the first ethylene homopolymer comprises 70% by weight of the total branched polyethylene; the second ethylene homopolymer comprises 30% by weight of the total branched polyethylene.
  13. 13 . The rubber composition according to claim 11 , wherein: both the first and second ethylene homopolymers have a secondary branch structure comprising branch-on-branch configuration formed by chain walking mechanism; and both the first and second ethylene homopolymers are produced by homopolymerization of ethylene in the presence of an (α-diimine) nickel catalyst.
  14. 14 . A rubber product reinforced with silica, wherein, the rubber compound used for said rubber product reinforced with silica comprises said rubber composition according to claim 1 .
  15. 15 . The rubber product reinforced with silica according to claim 14 , wherein, said rubber product reinforced with silica is used as rubber particles for a plastic track surface layer.
  16. 16 . The rubber product reinforced with silica according to claim 14 , wherein, said rubber product reinforced with silica is used as an insulating layer or sheathing layer for a cable.
  17. 17 . The rubber product reinforced with silica according to claim 14 , wherein, said rubber product reinforced with silica is a high-temperature resistant conveyor belt, which comprises a working surface covering rubber and a non-working surface covering rubber, wherein, the rubber compound used for at least one layer of said working surface covering rubber and said non-working surface covering rubber comprises said rubber composition.
  18. 18 . The rubber product reinforced with silica according to claim 14 , wherein, said rubber product reinforced with silica is a waterproof coil, a rubber plug, a rubber roller, an inner tube, or a catheter.
  19. 19 . The rubber product reinforced with silica according to claim 14 , wherein, said rubber product reinforced with silica is an air-conditioner rubber hose, which comprises a barrier layer, an inner rubber layer, a knitted layer and an outer rubber layer sequentially from the inside to the outside, wherein, the rubber compound used for the inner rubber layer comprises said rubber composition.

Description

CROSS REFERENCE TO RELATED APPLICATIONS The present application is the U.S. national phase of and claims priority to International Patent Application No. PCT/CN2018/072367 filed Jan. 12, 2018, which claims the benefit of priority from China National Application No. 201710025137.6, filed on Jan. 13, 2017 and China National Application No. 201810020839.X, filed on Jan. 10, 2018, the entire content of each of which is incorporated herein by reference into the present disclosure as if fully set forth herein. TECHNICAL FIELD The present invention belongs to the technical field of rubbers, and in particular relates to a rubber composition reinforced by silica and a processing method thereof, and a rubber product using the rubber composition. BACKGROUND Silica is the most commonly used light-color filler with good reinforcement. Ethylene-propylene rubber reinforced with silica often has the characteristics of good tear resistance, high adhesion strength, wet skid resistance, abrasion resistance and less heat generation, can be used to produce various rubber products such as waterproof coils, conveyor belts, plastic tracks, washing machine door seals, rubber rollers, rubber plugs, inner tubes, tire treads, tire sidewalls, and air-conditioner rubber hoses, but is weaker than ethylene-propylene rubber products reinforced by carbon black in terms of resilience, compression set resistance, and the like. Sulfur vulcanization and peroxide vulcanization are the two most commonly used vulcanization systems for ethylene-propylene rubber. Peroxide vulcanization can make vulcanized rubber have better heat resistance, aging resistance, resilience and compression set resistance, but it is weaker than sulfur vulcanized rubber in mechanical strength. Therefore, how to obtain better aging resistance, resilience, mechanical properties and compression set resistance of rubber products reinforced by silica in a peroxide-based vulcanization system is a problem to be solved. Ethylene-propylene rubbers are a kind of synthetic rubbers with a saturated molecular backbone, and include ethylene-propylene monomer (EPM) and ethylene-propylene-diene monomer (EPDM), both of which have good aging resistance. EPDM is commonly used in the ethylene-propylene rubber products. However, since the EPDM contains a third monomer with a molecular chain having a double bond and the EPM has a completely saturated molecular chain, the EPM has more excellent aging resistance. Therefore, in a situation where a higher requirement is raised for the aging resistance, it is a common technical solution to use the EPM in combination to improve the aging resistance of the EPDM. However, the mechanical strength of the EPM is low, which affects the overall physical and mechanical properties. The EPM is a copolymer of ethylene and propylene, which is a copolymer of ethylene and an α-olefin. The copolymer of ethylene and an α-olefin is a polymer containing only carbon and hydrogen elements and having a saturated molecular chain. The common types of carbon atoms found in such polymers generally include primary, secondary and tertiary carbons, in which the tertiary carbon is most susceptible to hydrogen abstraction to form a free radical. Accordingly, the proportion of tertiary carbon atoms in all carbon atoms is generally considered to be a major factor affecting the aging resistance of ethylene/α-olefin copolymers. The lower the proportion is, the better the aging resistance will be. The proportion can be expressed by the degree of branching. For example, EPM having a propylene content of 60% by weight can be calculated to contain 200 propylene units, that is, 200 tertiary carbon atoms or 200 methyl branches, per 1000 carbon atoms, so the degree of branching is 200 branches/1000 carbon atoms. The EPM usually has an ethylene content of 40-65% or 40-60% by weight, so the degree of branching is generally in the range of 117-200 branches/1000 carbon atoms or 133-200 branches/1000 carbon atoms. This degree of branching is considered to be higher than that of other common ethylene/α-olefin copolymers. In the prior art, the α-olefin in the common ethylene/α-olefin copolymers may include, in addition to propylene, an α-olefin having a carbon atom number of not less than 4, which may be selected from a C4-C20 α-olefin, and is generally selected from 1-butene, 1-hexene and 1-octene. If the degree of branching of an ethylene/α-olefin copolymer is too low, the melting point and crystallinity are too high, so it is not suitable for use as a rubber component. If the degree of branching is too high, the content of α-olefin is high, which leads to a higher process difficulty and raw material cost, and a lower operability and economical efficiency. In the prior art, a polyolefin obtained by copolymerizing ethylene with 1-butene or ethylene with 1-octene can be referred to as a polyolefin plastomer or a polyolefin elastomer according to the magnitudes of crystallinity and melting points.