# US 10,370,525 B2 · Rubber compositions

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- Number: US 10,370,525 B2
- Document ID: US10370525B2
- Status: Granted
- Kind: B2
- Application number: 15/125,420
- Filed: 2015-03-10
- Published: 2017-03-16
- Granted: 2019-08-06
- Earliest claimed: 2014-03-14
- Assignees: Kuraray Co., Ltd.
- Applicants: Kuraray Co., Ltd.
- Inventors: Daisuke Koda; Kei Hirata
- Web page: https://patentgrep.com/patent/US10370525B2

## CPC

- C08L 9/06: Copolymers with styrene
- B60C 1/00: Tyres characterised by the chemical composition or the physical arrangement or mixture of the composition
- C08C 19/28: Reaction with compounds containing carbon-to-carbon unsaturated bonds (graft polymers C08F279/00)
- C08K 3/06: Sulfur
- C08K 3/36: Silica
- C08K 5/09: Carboxylic acids; Metal salts thereof; Anhydrides thereof
- C08K 5/47: Thiazoles
- C08K 5/548: containing sulfur {(C08K5/5477 takes precedence)}
- C08L 7/00: Compositions of natural rubber
- C08L 15/00: Compositions of rubber derivatives (C08L11/00, C08L13/00 take precedence)
- C08L 91/00: Compositions of oils, fats or waxes; Compositions of derivatives thereof
- C08L 91/06: Waxes
- C08F 136/06: Butadiene
- C08F 236/06: Butadiene
- C08L 2205/06: having improved processability or containing aids for moulding methods
- Y02T 10/86: Optimisation of rolling resistance, e.g. weight reduction
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- B60C: VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- C08C: TREATMENT OR CHEMICAL MODIFICATION OF RUBBERS
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

[Object] The invention provides rubber compositions having excellent filler dispersibility, crosslinked products having excellent properties such as abrasion resistance, and tires that exhibit enhanced rolling resistance performance and attain simultaneous enhancements in steering stability and ice grip performance by virtue of using the compositions or the crosslinked products in portions of the tires. [Solution] The rubber composition includes 100 parts by mass of a solid rubber (A), 0.1 to 10 parts by mass of a modified liquid diene rubber (B) that is obtained by adding a modifying agent to an unmodified liquid diene rubber (B′) and has functional groups derived from the modifying agent, and 20 to 150 parts by mass of a filler (C). The modified liquid diene rubber (B) satisfies the following (i) to (iv): (i) the content of butadiene units is not less than 50 mass % relative to the total of all monomer units, (ii) the weight average molecular weight (Mw) is 25,000 to 120,000, (iii) the amount of the modifying agent added is 3 to 40 parts by mass per 100 parts by mass of the unmodified liquid diene rubber (B′), and (iv) the average number of functional groups per molecule of the modified liquid diene rubber (B) is 5 to 80.

## Claims

### Claim 1

A rubber composition, consisting of:
(A) 100 parts by mass of a solid rubber (A),
(B) 0.1 to 10 parts by mass of a modified liquid diene rubber (B) that is obtained by adding a modifying agent to an unmodified liquid diene rubber (B′) and has functional groups derived from the modifying agent,
(C) 20 to 150 parts by mass of a filler (C) consisting of an inorganic filler, and
(D) optionally at least one additional component selected from the group consisting of a crosslinking agent (D), a vulcanization accelerator (E), a vulcanization aid (F), a silane coupling agent, a softener, an antioxidant, a wax, an oxidation inhibitor, a lubricant, a light stabilizer, a scorch inhibitor, a processing aid, a colorant, a flame retardant, an antistatic agent, a matting agent, an antiblocking agent, a UV absorber, a release agent, a foaming agent, an antibacterial agent, a mildew-proofing agent, and a perfume,
wherein:
the modified liquid diene rubber (B) satisfies the following (i) to (iv):
(i) a content of butadiene units is not less than 50 mass % relative to the total of all monomer units,
(ii) a weight average molecular weight (Mw) is 25,000 to 120,000,
(iii) an amount of the modifying agent added is 3 to 40 parts by mass per 100 parts by mass of the unmodified liquid diene rubber (B′), and
(iv) an average number of functional groups per molecule of the modified liquid diene rubber (B) is 5 to 80, and
the modified liquid diene rubber (B) has a peak top molecular weight (Mt) of 25,000 to 120,000.

### Claim 2 (depends on 1)

The rubber composition according to claim 1, wherein the modified liquid diene rubber (B) has a functional group equivalent weight of 150 to 6,500 g/eq.

### Claim 3 (depends on 1)

The rubber composition according to claim 1, wherein the inorganic filler is at least one inorganic filler selected from the group consisting of a carbon black and a silica.

### Claim 4 (depends on 1)

The rubber composition according to claim 1, wherein the inorganic filler is at least one inorganic filler selected from the group consisting of a carbon black, a silica, a clay, a mica, calcium carbonate, magnesium hydroxide, aluminum hydroxide, barium sulfate, a titanium oxide, a glass fiber, a fibrous filler and a glass balloon.

### Claim 5 (depends on 1)

The rubber composition according to claim 1, wherein the modified liquid diene rubber (B) has a peak top molecular weight (Mt) of 25,000 to 90,000.

### Claim 6 (depends on 1)

The rubber composition according to claim 1, wherein the modified liquid diene rubber (B) has a peak top molecular weight (Mt) of 25,000 to 80,000.

### Claim 7 (depends on 1)

The rubber composition according to claim 1, wherein the modified liquid diene rubber (B) has a peak top molecular weight (Mt) of 30,000 to 70,000.

### Claim 8 (depends on 1)

The rubber composition according to claim 1, wherein the modified liquid diene rubber (B) has a catalyst residue content derived from a polymerization catalyst used in production of the rubber of 0 to 200 ppm in terms of metal.

### Claim 9 (depends on 1)

The rubber composition according to claim 1, wherein the modified liquid diene rubber (B) has a catalyst residue content derived from a polymerization catalyst used in production of the rubber of 0 to 150 ppm in terms of metal.

### Claim 10 (depends on 1)

The rubber composition according to claim 1, wherein the modified liquid diene rubber (B) has a catalyst residue content derived from a polymerization catalyst used in production of the rubber of 0 to 100 ppm in terms of metal.

### Claim 11 (depends on 1)

The rubber composition according to claim 1, wherein a proportion of polymer components of the modified liquid diene rubber (B) having a molecular weight of Mt×1.45 or above is 0 to 20%, assuming that a total area of peaks assigned to polymer components of the modified liquid diene rubber (B) in a GPC chromatogram obtained by GPC measurement of the modified liquid diene rubber (B) is 100%.

### Claim 12 (depends on 1)

The rubber composition according to claim 1, wherein a content of butadiene units in the modified liquid diene rubber (B) is 100 mass % relative to a total mass of all monomer units.

### Claim 13 (depends on 1)

The rubber composition according to claim 1, wherein a melt viscosity of the modified liquid diene rubber (B) measured at 38° C. is 50 to 2,000 Pa·s.

### Claim 14 (depends on 1)

The rubber composition according to claim 1, wherein the inorganic filler is at least one inorganic filler selected from the group consisting of a silica, an untreated carbon black, a carbon black treated with acid, a carbon black subjected to surface oxidation treatment, and a carbon black heat treated at 2,000 to 3,000° C. in the presence of a graphitization catalyst.

### Claim 15 (depends on 1)

The rubber composition according to claim 1, wherein the content of butadiene units in the modified liquid diene rubber (B) is 60 to 100 mass % relative to the total of all monomer units.

### Claim 16 (depends on 1)

The rubber composition according to claim 1, wherein:
the antioxidant is present in the composition; and
the modified liquid diene rubber (B) is prepared by adding the antioxidant during the addition reaction of the modifying agent.

### Claim 17 (depends on 1)

The rubber composition according to claim 1, the modified liquid diene rubber (B) is prepared by adding the antioxidant during the addition reaction of the modifying agent, the antioxidant being added in an amount of 0.01 to 10 parts by mass per 100 parts of the unmodified liquid diene rubber (B′).

### Claim 18 (depends on 1)

The rubber composition according to claim 1, wherein the functional groups possessed by the modified liquid diene rubber (B) are at least one selected from the group consisting of a carboxylic anhydride group, a dicarboxylic acid monoester group and a dicarboxylic acid monoamide group.

### Claim 19 (depends on 18)

The rubber composition according to claim 18, wherein the functional groups possessed by the modified liquid diene rubber (B) are at least one selected from the group consisting of a maleic anhydride group, a succinic anhydride group, a maleic acid monoester group, a succinic acid monoester group, a maleic acid monoamide group and a succinic acid monoamide group.

### Claim 20 (depends on 1)

A crosslinked product obtained by crosslinking the rubber composition of claim 1.

### Claim 21 (depends on 20)

A tire, comprising the crosslinked product of claim 20 in at least a portion of the tire.

### Claim 22 (depends on 1)

A tire, comprising the rubber composition of claim 1 in at least a portion of the tire.