Adhesion modifier for rubber

Abstract

To provide an adhesion modifier for rubber which is capable of yielding a rubber composition having superior adhesion to fibers, metals, and the like.SOLUTION: The present invention provides a rubber adhesion modifier comprising an aromatic petroleum resin that has a bromine number (Br2 / 100 g) of 20 to 80 g as measured in accordance with JIS K2605, a softening point of 70 to 140°C, and a weight average molecular weight of 500 to 6000 in terms of standard polystyrene as determined by gel permeation chromatography, and an aromatic group content of 10 to 100 mol%, as well as a rubber composition employing the rubber adhesion modifier.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an adhesion modifier for rubber, and is an aromatic petroleum resin that can provide a rubber composition excellent in adhesion to fibers, metals, etc. by being blended with rubber.

Background Art

[0002] In rubber products such as tires, hoses, belts, and air springs used in the fields of automobiles, industrial parts, and building materials, short fibers, yarns, fabrics, canvas, metal cords, metal wires, etc. are used as reinforcing materials.

[0003] With the recent trend towards energy conservation, weight reduction of rubber products has been demanded, and the thermal input and dynamic strain input applied to products tend to be larger than before. Therefore, in addition to improving the thermal stability and fatigue fracture life of the strength, modulus, etc. of various members constituting the product, the adhesion between the reinforcing material and the rubber is also stable and strong so that the product life can be fully achieved for such input. It is required to be.

[0004] Therefore, as a method for improving the adhesion between the reinforcing material and the rubber, for example, a technique of blending a specific carbon black, a specific phenolic resin, and a methylene donor compound with a diene rubber (see, for example, Patent Document 1), and a technique of blending a specific amount of a phenolic resin and an organic acid cobalt salt with a diene rubber (see, for example, Patent Document 2), and further, a styrene-isobutylene block copolymer and a brominated alkylphenol formaldehyde resin, a phenolic resin, and methylol melamine are blended with a halogenated butyl rubber. Techniques (see, for example, Patent Document 3), etc. have been proposed.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] However, from the perspective of CO2 reduction, further weight reduction and longer life are required for rubber products. None of the proposals in Patent Documents 1 to 3 have achieved satisfactory results, and continuous improvement in the adhesion between the reinforcing material and the rubber is still required.

[0007] Therefore, an object of the present invention is to provide an adhesive modifier for rubber that solves these problems and enables the provision of a rubber composition that improves the adhesion between the reinforcing material and the rubber. [Means for Solving the Problems]

[0008] As a result of intensive studies to solve the above problems, the present inventors have found that a specific aromatic petroleum resin can provide a rubber composition that exhibits particularly excellent adhesion, and have thus completed the present invention.

[0009] That is, the present invention relates to an adhesive modifier for rubber, which is an aromatic petroleum resin having a bromine value (Br2 / 100g) measured in accordance with JIS K2605 of 20 to 80 g, a softening point of 70 to 140 ° C, and a weight average molecular weight in terms of standard polystyrene by gel permeation chromatography of 500 to 6000, and having an aromatic group component of 10 to 100 mol%.

[0010] The present invention will be described in detail below.

[0011] The adhesion modifier for rubber of the present invention is composed of an aromatic petroleum resin. The bromine value (Br2 / 100g) of the aromatic petroleum resin measured in accordance with JIS K2605 is 20 to 80 g, the softening point is 70 to 140 °C, and the weight average molecular weight in terms of standard polystyrene by gel permeation chromatography (hereinafter sometimes referred to as Mw) is 500 to 6,000, and it has 10 to 100 mol% of an aromatic group component. Here, when the bromine value is less than 20 g, when the softening point is less than 70 °C, or when Mw is less than 500, the adhesiveness in the case of forming a rubber composition will be inferior. On the other hand, when it exceeds 80 g or when the aromatic group component is less than 10 mol%, the crosslink density of the rubber composition decreases, and the tensile strength becomes inferior. Also, when the softening point exceeds 140 °C or when Mw exceeds 6,000, the processability when forming a rubber composition becomes inferior.

[0012] And since it is particularly suitable as an adhesion modifier for rubber, those in any range of a bromine value of 25 to 65 g, a softening point of 85 to 125 °C, and Mw of 600 to 4,000 are preferably used, and the aromatic group component preferably has 30 to 90 mol%.

[0013] Specific examples of the aromatic petroleum resin constituting the rubber adhesion improver of the present invention include, for example, aromatic petroleum resins, aliphatic-aromatic petroleum resins, aromatic-dicyclopentadiene copolymerized petroleum resins, etc. Examples of the aromatic group component at that time include those derived from, for example, styrene components, α-methylstyrene components, β-methylstyrene components, vinyltoluene components, indene components, methylindene components, etc. And, as the aromatic petroleum resin, a resin obtained from an aromatic component fraction which is a fraction having a boiling point range of 140 to 280 ° C (sometimes referred to as a C9 fraction) obtained by thermal decomposition of petroleum can be mentioned. Further, as the aliphatic-aromatic petroleum resin, a petroleum resin which is a copolymer of an aliphatic component fraction which is a fraction having a boiling point range of 20 to 110 ° C (sometimes referred to as a C5 fraction) obtained by thermal decomposition of petroleum and the aromatic component fraction can be mentioned. Examples of the monomer constituting the aliphatic fraction at that time include chain aliphatics such as isoprene and piperylene; and cyclic aliphatics such as cyclopentadiene, methylcyclopentadiene, dicyclopentadiene, methyldicyclopentadiene, and dimethyldicyclopentadiene. Furthermore, as the aromatic-dicyclopentadiene copolymerized petroleum resin, a petroleum resin which is a copolymer of dicyclopentadienes and the aromatic component fraction can be mentioned. Examples of the dicyclopentadienes at that time include cyclopentadiene, methylcyclopentadiene, dicyclopentadiene, dimethylcyclopentadiene, etc.

[0014] The adhesion improver for rubber of the present invention can provide a rubber composition excellent in adhesion to a reinforcing material by being compounded with, for example, natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, ethylene-propylene-diene rubber, butyl rubber, halogenated butyl rubber, acrylonitrile-butadiene rubber, chloroprene rubber, silicone rubber, styrenic elastomer (sometimes referred to as TPS), olefinic elastomer (sometimes referred to as TPO), urethane elastomer (sometimes referred to as TPU), polyester elastomer (sometimes referred to as TPEE), polyamide elastomer (sometimes referred to as TPA), polybutadiene elastomer (sometimes referred to as RB), polyvinyl chloride (sometimes referred to as PVC), ethylene / vinyl acetate copolymer (sometimes referred to as EVA), etc. Among them, natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, ethylene-propylene-diene rubber, acrylonitrile-butadiene rubber are preferred.

[0015] When preparing the rubber composition, fillers generally used, such as silica, carbon black, calcium carbonate, talc, clay, mica, alumina, aluminum hydroxide, glass fiber, glass bead, glass balloon, carbon fiber, etc., may be compounded. Furthermore, silane coupling agent, crosslinking agent, crosslinking accelerator, softening agent, plasticizer, flame retardant, anti-aging agent, zinc oxide, magnesium oxide, stearic acid, cobalt salt of organic acid, liquid rubber, resorcinol formalin resin, phenolic resin, rosin resin, etc. may be appropriately selected and compounded within the range of normal compounding amounts.

[0016] When preparing the rubber composition, various compounding agents appropriately selected as needed can be compounded and mixed using a mixing method such as a Banbury mixer, pressure kneader, open roll, etc. Furthermore, the obtained unvulcanized compound can be manufactured into a rubber composition by being formed into a sheet shape using, for example, a calender, roll, extruder, etc., and then crosslinked in a heat medium.

[0017] The rubber composition containing the rubber adhesion improver of the present invention has excellent adhesion to a reinforcing material, and thus can provide a reinforced rubber structure excellent in adhesion, strength, durability, etc. Examples of the reinforced rubber structure in this case include rubber products such as tires, hoses, cables, belts, rolls, air springs, and rubber-coated fabrics. In particular, it is suitable for reinforced rubber structures such as tires, hoses, and belts that require heat resistance deterioration resistance and moisture and heat resistance deterioration resistance, and also require durability to withstand use in harsh environments. Further, the reinforcing material is not limited by its shape or the like, and examples thereof include fibrous structures such as short fibers, yarns, ropes, woven fabrics, and canvas; metal structures such as metal plates, metal chips, metal cords, and metal wires. Examples of the fibers constituting the fibrous structure include natural fibers and synthetic fibers, and may further be fibers surface-treated with resorcinol-formalin-rubber latex (sometimes referred to as RFL). The metal constituting the metal structure is not particularly limited, and examples thereof include steel, stainless steel, aluminum, aluminum alloy, titanium, titanium alloy, zinc, copper, copper alloy, brass, bronze, and other alloys, and may be a metal structure plated with brass or the like.

Effects of the Invention

[0018] According to the present invention, it is possible to provide an adhesive modifier for rubber that can be made into a rubber composition that particularly exhibits excellent adhesion to a reinforcing material.

Examples

[0019] Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. The raw materials for the rubber composition, reinforcing materials, analysis, and test methods used in the Examples and Comparative Examples are as follows.

[0020] 1. Raw Materials for Rubber Composition 1) Rubber Natural rubber (hereinafter sometimes referred to as NR): SVR3L manufactured by Shenggong Trading Co., Ltd. (trade name). Styrene-butadiene rubber (hereinafter sometimes referred to as SBR): Nipol 1502, manufactured by Zeon Corporation, Japan. Ethylene propylene diene rubber (hereinafter sometimes referred to as EPDM): EP35, manufactured by ENEOS MATERIALS.

[0021] 2) Filler Carbon black: Asahi #60, manufactured by Asahi Carbon. Silica: Nipsil VN3, manufactured by Tosoh Silica. Calcium carbonate: Heavy calcium carbonate, manufactured by Maruo Calcium. Zinc oxide: Zinc Oxide Type 1, manufactured by Sakai Chemical Industry.

[0022] 3) Rubber modifier Petroleum resin 1: Manufactured by the method described in Production Example 1. Petroleum resin 2: Manufactured by the method described in Production Example 2. Petroleum resin 3: Manufactured by the method described in Production Example 3. Aromatic-containing hydrocarbon resin 4 (hereinafter sometimes referred to as hydrocarbon resin 4): NOVARES TP100, manufactured by RAIN CARBON. Aliphatic hydrocarbon resin: T-REZ RA100, manufactured by ENEOS. Aromatic-containing hydrocarbon resin 5 (hereinafter sometimes referred to as hydrocarbon resin 5): NOVARES TL10, manufactured by RAIN CARBON.

[0023] 4) Other compounding agents Silane coupling agent: Si69, manufactured by Evonik. Oil: Diana Process Oil PW-90, manufactured by Idemitsu Kosan. Stearic acid: NAA-180, manufactured by NOF Corporation. Cobalt stearate: Co-STEARATE, manufactured by DIC Corporation. Antioxidant: No Crack 810-NA, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd. Insoluble sulfur: Sunfel, manufactured by Sanshin Chemical Industry Co., Ltd. Vulcanization accelerator (TBBS): manufactured by Sanshin Chemical Industry Co., Ltd. (trade name: Sunseller NS-G). Vulcanization accelerator (MBT): manufactured by Ouchi Shinko Chemical Industry Co., Ltd. (trade name: Nocceler M-P). Vulcanization accelerator (TMTD): manufactured by Ouchi Shinko Chemical Industry Co., Ltd. (trade name: Nocceler TT-P). Vulcanization accelerator (CBS): manufactured by Ouchi Shinko Chemical Industry Co., Ltd. (trade name: Nocceler CZ-G). Vulcanization accelerator (DPTT): manufactured by Ouchi Shinko Chemical Industry Co., Ltd. (trade name: Nocceler TRA-P).

[0024] 2. Reinforcing material Fiber structure: Twill feather RFL-treated nylon canvas. Metal structure: Brass plate made of standard test pieces.

[0025] 3. Analysis and evaluation methods <Bromine number> Measured in accordance with JIS K2605.

[0026] <Softening point> Measured in accordance with JIS K-2207.

[0027] <Weight-average molecular weight> Using standard polystyrene as a standard substance, the weight-average molecular weight (Mw) was measured by gel permeation chromatography.

[0028] <Aromatic group component> In deuterated chloroform, the 1H-NMR spectrum was measured using a nuclear magnetic resonance spectrometer (manufactured by JEOL Ltd., (trade name) GSX400, frequency 400 MHz).

[0029] <Preparation of unvulcanized rubber composition> The rubber formulations described in Tables 2, 3, and 4 were kneaded using a Banbury mixer. After performing finish kneading, a sheet was formed to a thickness of 2 mm using an 8-inch roll to obtain an unvulcanized rubber composition.

[0030] <Preparation of rubber structure> The sheet of the obtained unvulcanized rubber composition was directly laminated with an RFL-treated nylon canvas or brass plate, and vulcanized at a vulcanization temperature of 150 °C for 30 minutes using a steam heating press to prepare a rubber structure.

[0031] <Measurement of peel strength and rubber residue ratio of rubber structure (fiber structure)> Using a tensile testing machine (manufactured by A&D, (trade name) Tensilon RTG), a test piece with a length of 150 mm and a width of 25 mm was used to measure the peel strength between rubber / fiber according to the peel test method described in JIS K6404-2. The rubber residue ratio remaining on the fiber side was measured by binarizing the image obtained by observing the peeled surface on the fiber side after the peel test with a digital microscope (manufactured by Hiros, (trade name) HRX-01).

[0032] <Measurement of peel strength and rubber residue ratio of rubber structure (metal structure)> Using a tensile testing machine (manufactured by A&D, (trade name) Tensilon RTG), a test piece with a length of 100 mm and a width of 25 mm was used to measure the peel strength between rubber / metal according to the peel test method described in JIS K6256-2. The rubber residue ratio remaining on the metal side was measured by binarizing the image obtained by observing the peeled surface on the metal side after the peel test with a digital microscope (manufactured by Hiros, (trade name) HRX-01).

[0033] Production Example 1 Into an autoclave made of glass with an internal volume of 2 liters, 25% by weight of a raw material oil obtained by decomposing naphtha (3% by weight of C4 components, 50% by weight of pentanes, 20% by weight of pentenes, 12% by weight of isoprene, 7% by weight of piperylene, 9% by weight of cyclopentadiene) and 75% by weight of a C9 fraction (11% by weight of styrene, 2% by weight of α-methylstyrene, 4% by weight of β-methylstyrene, 8% by weight of vinyltoluene, 14% by weight of indene, 30% by weight of C10 olefins, 15% by weight of C9 saturated aromatics) were prepared and charged. Next, after adjusting the temperature to 40°C under a nitrogen atmosphere, 1.6 parts by weight of boron trifluoride isobutanol complex as a Friedel-Crafts type catalyst was added to 100 parts by weight of the raw material oil and polymerized for 2 hours. Then, the catalyst was deactivated and removed with an aqueous sodium hydroxide solution, the oil phase was recovered, and unreacted raw material oil was removed by distillation from the oil phase to obtain an aliphatic-aromatic petroleum resin 1 having an aromatic group component of 72 mol%, a bromine number of 34 g, a softening point of 101°C, and a weight average molecular weight of 1700 (hereinafter, may be referred to as petroleum resin 1). The results are shown in Table 1.

[0034] Production Example 2 An aliphatic-aromatic petroleum resin 2 (hereinafter, may be referred to as petroleum resin 2) was obtained in the same manner as in Production Example 1, except that the C5 fraction was 57% by weight and the C9 fraction was 43% by weight. The obtained petroleum resin 2 had an aromatic group component of 41 mol%, a bromine number of 42 g, a softening point of 97°C, and a weight average molecular weight of 3500. The results are shown in Table 1.

[0035] Production Example 3 An aromatic petroleum resin 3 (hereinafter, may be referred to as petroleum resin 3) was obtained in the same manner as in Production Example 1, except that the C9 fraction was 100% by weight. The obtained petroleum resin 3 had an aromatic group component of 100 mol%, a bromine number of 25 g, a softening point of 95°C, and a weight average molecular weight of 1400. The results are shown in Table 1.

[0036]

Table 1

[0037] Example 1 Based on a total of 100 parts by weight of 70 parts by weight of NR and 30 parts by weight of SBR, 10 parts by weight of petroleum resin 1 obtained according to Production Example 1, 40 parts by weight of carbon black, 5 parts by weight of silica, 5 parts by weight of zinc oxide, 0.5 parts by weight of silane coupling agent, 5 parts by weight of oil, 2 parts by weight of stearic acid, 2 parts by weight of antioxidant, 3 parts by weight of sulfur, and 1 part by weight of vulcanization accelerator (TBBS) were compounded as a rubber formulation and kneaded with a Banbury mixer. After performing finish kneading, it was sheeted to a thickness of 2 mm using an 8-inch roll to obtain an unvulcanized rubber composition.

[0038] The sheet of the obtained unvulcanized rubber composition was directly laminated with the RFL-treated nylon canvas and vulcanized at a vulcanization temperature of 150 °C and a vulcanization time of 30 minutes using a steam heating press to obtain a fiber-reinforced rubber structure.

[0039] The evaluation results are shown in Table 2. The obtained fiber-reinforced rubber structure was excellent in peel strength and rubber retention rate and was suitable as a fiber-reinforced rubber structure.

[0040] Examples 2 and 3 A fiber-reinforced rubber structure was obtained in the same manner as in Example 1, except that petroleum resin 2 obtained in Production Example 2 and petroleum resin 3 obtained in Production Example 3 were used instead of petroleum resin 1.

[0041] The evaluation results are shown in Table 2. The obtained fiber-reinforced rubber structure was excellent in peel strength and rubber retention rate and was suitable as a fiber-reinforced rubber structure.

[0042] Examples 4 to 6 A fiber-reinforced rubber structure was obtained in the same manner as in Example 1, except that EPDM was used instead of NR and SBR to form the rubber composition shown in Table 2.

[0043] The evaluation results are shown in Table 2. The obtained fiber-reinforced rubber structure was excellent in peel strength and rubber retention rate and was suitable as a fiber-reinforced rubber structure.

[0044] Examples 7 to 9 A metal-reinforced rubber structure was obtained in the same manner as in Example 1, except that natural rubber (NR) was used instead of NR and SBR, and brass plates were used instead of RFL-treated nylon canvas, and the rubber composition shown in Table 2 was used.

[0045] The evaluation results are shown in Table 2. The obtained metal-reinforced rubber structure was excellent in peel strength and rubber residue ratio and was suitable as a metal-reinforced rubber structure.

[0046]

Table 2

[0047] Comparative Example 1 A rubber structure was obtained in the same manner as in Example 1, except that petroleum resin 1 was not used.

[0048] The evaluation results are shown in Table 3. The obtained rubber structure was inferior in peel strength and rubber residue ratio and was not suitable as a rubber structure.

[0049] Comparative Examples 2 to 4 A rubber structure was obtained in the same manner as in Example 1, except that hydrocarbon resin 4 (aromatic group component 90 mol%, bromine number 15 g, softening point 100 °C, weight average molecular weight 1770), aliphatic hydrocarbon resin (aromatic group component 0 mol%, bromine number 27 g, softening point 96 °C, weight average molecular weight 3100), and hydrocarbon resin 5 (aromatic group component 100 mol%, bromine number 6 g, softening point 10 °C, weight average molecular weight 320) were used instead of petroleum resin 1.

[0050] The evaluation results are shown in Table 3. The obtained rubber structure was inferior in peel strength and rubber residue ratio and was not suitable as a rubber structure.

[0051] Comparative Example 5 A rubber structure was obtained in the same manner as in Example 4, except that petroleum resin 1 was not used.

[0052] The evaluation results are shown in Table 3. The obtained rubber structure was inferior in peel strength and rubber residue ratio and was not suitable as a rubber structure.

[0053] Comparative Examples 6 to 8 A rubber structure was obtained in the same manner as in Example 4, except that hydrocarbon resin 4, aliphatic hydrocarbon resin, and hydrocarbon resin 5 were used instead of petroleum resin 1.

[0054] The evaluation results are shown in Table 3. The obtained rubber structure was inferior in peel strength and rubber residue ratio and was not suitable as a rubber structure.

[0055]

Table 3

[0056] Comparative Example 9 A rubber structure was obtained in the same manner as in Example 7 without using petroleum resin 1.

[0057] The evaluation results are shown in Table 4. The obtained rubber structure was inferior in peel strength and rubber residue ratio and was not suitable as a rubber structure.

[0058] Comparative Examples 10 to 12 A rubber structure was obtained in the same manner as in Example 7, except that hydrocarbon resin 4, aliphatic hydrocarbon resin, and hydrocarbon resin 5 were used instead of petroleum resin 1.

[0059] The evaluation results are shown in Table 4. The obtained rubber structure was inferior in peel strength and rubber residue ratio and was not suitable as a rubber structure.

[0060]

Table 4

Industrial Applicability

[0061] The rubber adhesion improver of the present invention can provide a rubber composition excellent in adhesion to fibers, metals, etc., and can be suitably used as fiber-reinforced rubber structures such as tires, hoses, cables, belts, rolls, and rubber conveyor belts, and metal-reinforced rubber structures.

Claims

1. An adhesion modifier for rubber, characterized in that it is an aromatic petroleum resin having a bromine value (Br2 / 100 g) measured in accordance with JIS K2605 of 20 to 80 g, a softening point of 70 to 140°C, a weight average molecular weight in terms of standard polystyrene by gel permeation chromatography of 500 to 6000, and an aromatic group component of 10 to 100 mol%.

2. The adhesion modifier for rubber according to Claim 1, characterized in that the aromatic petroleum resin is at least one aromatic petroleum resin selected from the group consisting of aromatic petroleum resins, aliphatic-aromatic petroleum resins, and aromatic-dicyclopentadiene copolymer petroleum resins.

3. A rubber composition, characterized in that it contains 5 to 150 parts by weight of a filler (B) and 1 to 50 parts by weight of the adhesion modifier for rubber according to Claim 1 with respect to 100 parts by weight of a rubber component (A).

4. The rubber composition according to Claim 3, characterized in that the rubber component (A) is at least one rubber selected from natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, chloroprene rubber, acrylonitrile-butadiene rubber, ethylene-propylene rubber, and ethylene-propylene-diene rubber.

5. The rubber composition according to Claim 3, characterized in that the filler (B) is at least one filler selected from silica, carbon black, calcium carbonate, aluminum hydroxide, magnesium oxide, alumina, and clay.

6. A fiber-reinforced rubber structure, characterized in that it is an adhesion reinforcing material between a structure made of the rubber composition according to Claim 3 and a fiber structure.

7. A metal-reinforced rubber structure, characterized in that it is an adhesion reinforcing material between a structure made of the rubber composition according to Claim 3 and a metal structure.

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