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US-12624196-B2 - Rubber composition, vulcanized object obtained from said rubber composition, and vulcanized molded object obtained from said rubber composition

US12624196B2US 12624196 B2US12624196 B2US 12624196B2US-12624196-B2

Abstract

A rubber composition, by which a vulcanizate having excellent vulcanization speed, abrasion resistance and low temperature rise can be obtained, is provided. A rubber composition including 100 parts by mass of a chloroprene-based rubber, 20 to 80 parts by mass of silica, 1 part by mass or more and less than 20 parts by mass of a hydrate, and 0.3 to 1.4 parts by mass of an organic peroxide, wherein the rubber composition includes 0.5 to 15 parts by mass of a silane coupling agent having a double bond in a structure of the silane coupling agent with respect to 100 parts by mass of the silica.

Inventors

  • Atsunori Kondo

Assignees

  • DENKA COMPANY LIMITED

Dates

Publication Date
20260512
Application Date
20211119
Priority Date
20201126

Claims (11)

  1. 1 . A rubber composition comprising: 100 parts by mass of a chloroprene-based rubber; 20 to 80 parts by mass of silica; 1 part by mass or more and less than 20 parts by mass of a hydrate; and 0.3 to 1.4 parts by mass of an organic peroxide, wherein: the rubber composition includes 0.5 to 15 parts by mass of a silane coupling agent having a double bond in a structure of the silane coupling agent with respect to 100 parts by mass of the silica and a rubber component contained in the rubber composition consists of the chloroprene-based rubber.
  2. 2 . The rubber composition of claim 1 , wherein the chloroprene-based rubber contains a homopolymer of 2-chloro-1,3-butadiene or a copolymer of 2-chloro-1,3-butadiene and at least one monomer selected from 2,3-dichloro-1,3-butadiene and acrylonitrile.
  3. 3 . The rubber composition of claim 1 , wherein the silane coupling agent having a double bond in the structure of the silane coupling agent is at least one silane coupling agent selected from vinyltrimethoxysilane, vinyltriethoxysilane, 3-(meth)acryloxypropyl methyl dimethoxysilane, 3-(meth)acryloxypropyl methyl trimethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane and 3-(meth)acryloxypropylmethyltriethoxysilane.
  4. 4 . The rubber composition of claim 1 , wherein the hydrate is a hydrate releasing H 2 O in a temperature range of 100° C. to 250° C.
  5. 5 . The rubber composition of claim 1 , wherein the hydrate is at least one hydrate selected from a hydrotalcite compound represented by formula (1), a hydrated salt, and a metal hydroxide, [M 2+ 1-x M 3+ x (OH) 2 ] x+ [A n− x/n ·m H 2 O] x− (1) in the formula (1), M 2+ is at least one divalent metal ion selected from Mg 2+ , Mn 2+ , Fe 2+ , Co 2+ , Ni 2+ , Cu 2+ , and Zn 2+ , M 3+ is at least one trivalent metal ion selected from Al 3+ , Fe 3+ , Cr 3+ , Co 3+ , and In 3+ , and A n− is at least one anion selected from OH − , F − , Cl − , Br − , NO 3 − , CO 3 2− , SO 4 2− , Fe(CN) 6 3− , and CH 3 COO − , and X satisfies 0<X≤0.4; and m>0.
  6. 6 . The rubber composition of claim 1 , wherein the hydrate is at least one hydrate selected from hydrotalcite compounds represented by Mg 4.3 Al 2 (OH) 12.6 CO 3 ·3.5H 2 O, Mg 3 ZnAl 2 (OH) 12 CO 3 ·3H 2 O, Mg 4.5 Al 2 (OH) 13 CO 3 ·3.5H 2 O, Mg 4.5 Al 2 (OH) 13 CO 3 , Mg 4 Al 2 (OH) 12 CO 3 ·3.5H 2 O, Mg 6 Al 2 (OH) 16 CO 3 ·4H 2 O, Mg 5 Al 2 (OH) 14 CO 3 ·4H 2 O, and Mg 3 Al 2 (OH) 10 CO 3 ·1.7H 2 O.
  7. 7 . The rubber composition of claim 1 , wherein the organic peroxide is at least one organic peroxide selected from dicumyl peroxide, 1,4-bis[(t-butylperoxy)isopropyl]benzene, t-butyl α-cumyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, and 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3.
  8. 8 . The rubber composition of claim 1 , wherein the silica has a cetyltrimethylammonium bromide (CTAB) adsorption specific surface area of 50 to 300 m 2 /g.
  9. 9 . A vulcanizate of the rubber composition of claim 1 .
  10. 10 . A vulcanized molded body of the rubber composition of claim 1 .
  11. 11 . The rubber composition of claim 1 , wherein the rubber composition has a vulcanization speed T90-T10 of 25 minutes or less at 160° C. for 60 minutes, measuring in accordance with the Society of Rubber Industry, Japan Standard SRIS 3102-1977.

Description

TECHNICAL FIELD A chloroprene-based rubbers is excellent in mechanical properties, ozone resistance, and chemical resistance, and are used in a wide range of fields such as automobile parts, adhesives, and various industrial rubber parts, taking advantage of these properties. In recent years, the performance required for rubber parts has increased significantly, and in addition to mechanical properties such as abrasion resistance and low temperature rise in dynamic environments, improving the vulcanization speed is required to improve productivity. BACKGROUND ART As a technology for improving the vulcanization speed of rubber, as described in Patent Literature 1, it is known that a rubber composition characterized by blending 5 to 200 parts by mass of silica and 0.1 to 10 parts by mass of a cyclic polysulfide represented by formula (1) with respect to 100 parts by mass of diene rubber, and 1 to 20% by mass of silane coupling agent with respect to the mass of the silica, 1 to 20% by mass of a glycerin mono fatty acid ester derived from a fatty acid having a carbon number of 8 to 24 with respect to the mass of the silica. In addition, as a technique for improving the abrasion resistance of a rubber, as described in Patent Literature 2, a composition for chloroprene vulcanized rubber is known. The composition for chloroprene vulcanized rubber comprises 100 parts by mass of a polymer for chloroprene vulcanized rubber, 0.5 to 6 parts by mass of an acid acceptor, 0.2 to 3 parts by mass of a lubricant, 1 to 5 parts by mass of an antioxidant, 10 to 120 parts by mass of carbon black, 0.1 to 20 parts by mass of a filler other than carbon black, 2 to 40 parts by mass of a softening agent, 0.2 to 5 parts by mass of a processing aid, 0.5 to 10 parts by mass of a metal oxide, 0.5 to 5 parts by mass of a vulcanization accelerator, wherein the polymer is a copolymer comprising 80 to 97% by mass of 2-chloro-1,3-butadiene (chloroprene) (C-1) and 20 to 3% by mass of 2,3-dichloro-1,3-butadiene (C-2); or 79.8 to 96.8% by mass of 2-chloro-1,3-butadiene (chloroprene) (C-1), 20 to 3% by mass of 2,3-dichloro-1,3-butadiene (C-2) and 0.2 to 17% by mass of a monomer copolymerizable with these (C-3), as a fraction of each monomer constituting the polymer with respect to 100% by mass of the total amount of all monomers, and the Mooney viscosity (ML1+4 (100° C.)) of the polymer is in the range of 100 to 135. As a technique for reducing the temperature rise of rubber, as described in Patent Literature 3, a rubber composition is known. The rubber composition comprises more than 0 to 100 parts by mass of silica with respect to 100 parts by mass of total rubber components including two or more kinds of diene rubber, wherein the diene rubber is divided into two or more phases each having a different glass transition temperature, at least one phase of which has a continuous structure, and at least one phase of which has a glass transition temperature of −50° C. or higher, and 80% or more by mass of the amount of silica per unit volume of the blended rubber is contained in the at least one phase having a glass transition temperature of −50° C. or higher, and the average aggregate area of the silica contained in the phase is less than 2000 nm2. CITATION LIST Patent Literature Patent Literature 1 JP-A-2016-113500Patent Literature 2 JP-A-2012-211345Patent Literature 3 JP-A-2014-196407 SUMMARY OF INVENTION Technical Problem For rubber compositions containing a chloroprene polymer, it is required to achieve a high degree of compatibility of various properties in a vulcanizate of the rubber composition, and it may be required to provide the vulcanizate having excellent abrasion resistance, low temperature rise in a dynamic environment, excellent vulcanization speed and high productivity. An object of one aspect of the present invention is to provide a rubber composition having excellent abrasion resistance, low temperature rise in a dynamic environment, excellent vulcanization speed and high productivity. Another object of the present invention is to provide a vulcanizate of the rubber composition. A main object of another aspect of the present invention is to provide a vulcanized molded body of the rubber composition. Solution To Problem One aspect of the present invention relates to a rubber composition comprising 100 parts by mass of a chloroprene-based rubber, 20 to 80 parts by mass of silica, 1 part by mass or more and less than 20 parts by mass of a hydrate, and 0.3 to 1.4 parts by mass of an organic peroxide, wherein the rubber composition includes 0.5 to 15 parts by mass of a silane coupling agent having a double bond in a structure of the silane coupling agent with respect to 100 parts by mass of the silica. Preferably, the chloroprene-based rubber contains a homopolymer of 2-chloro-1,3-butadiene or a copolymer of 2-chloro-1,3-butadiene and at least one monomer selected from 2,3-dichloro-1,3-butadiene and acrylonitrile. Preferably, the silan