JPS63309538A - Rubber composition - Google Patents

Abstract

PURPOSE:To obtain a rubber composition excellent in elasticity and compressive strength, by mixing a natural rubber and/or a synthetic rubber with a specified surface-treated fine inorganic fibrous substance and a nonsulfur vulcanizer. CONSTITUTION:A fine inorganic fibrous substance (e.g., potassium titanate fiber) of a fiber length of 1mum-1mm and an aspect ratio of 5-1,000 is surface- treated with 0.05-10wt.% mercapto silane compound of formula I [wherein R<1> is an (un)substituted 2-6C bivalent hydrocarbon group, R<2> is an (un) substituted monovalent hydrocarbon group, X is a hydrolyzable group, a is 1-3, b is 0-2, and 1<=(a+b)<=3] and/or a silylated sulfide compound of formula II [wherein R<3> is R<2>, R<4> is an (un)substituted 2-4C hydrocarbon group, Y is X, c is 0-2, and n is 1-6] to obtain a surface-treated fine inorganic fibrous substance (B). 100pts.wt. natural rubber and/or synthetic rubber (A) (e.g., isoprene rubber) are kneaded with 0.1-50pts.wt. component B and 0.1-15wt.%, based on component A, nonsulfur vulcanizer (e.g., MgO), and the mixture is vulcanized by heating at 80-180 deg.C for 5-60min.

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a rubber composition with improved strength properties, particularly compressive strength. (Prior Art) Unlike plastics, rubber compositions exhibit viscoelasticity and are therefore used in a wide range of fields such as civil engineering, machinery, electrical, and chemical industries. However, just as high-strength plastics have appeared as needs have diversified in recent years, demands for high hardness, high elasticity, high strength, ultra-high pressure compressive strength, and excellent abrasion resistance have also increased for rubber compositions. Moreover, there is a need for a product that exhibits at least two or more of these characteristics. Various proposals have been made regarding the addition of fine inorganic powders to improve hardness and abrasion properties, but all of these methods result in a decrease in elasticity, compressive fracture, and a decrease in strength, and long fibers are required to develop strength. Although this method was effective, the surface smoothness deteriorated, and improvements in elasticity and hardness cannot be expected at present. Naturally, the use of fine fibers was presumed based on the ideas of these conventional technologies, but although they are homogeneously dispersed in the rubber composition, they do not wet well with the rubber, causing slippage on the fibrous surface, resulting in poor performance. However, surface treatment of the fibrous surface was a major issue. Hydrolyzable silyl compounds were known to be effective as surface treatment techniques, but they required selection depending on the type of rubber component and required skill in determining hardness. The present inventor has already obtained knowledge that sulfur-containing silyl compounds are compatible with rubber components and are excellent surface treatment agents, but all of these are for sulfur-cured systems, and conventional The compound inhibits vulcanization with non-sulfur vulcanizing agents due to its vulcanization structure, and was considered to be impractical. (Problems to be Solved by the Invention) The object of the present invention is to provide a rubber composition that is vulcanized with a non-sulfur vulcanizing agent and has high elasticity, high strength, high compressibility, etc. Our goal is to provide the following. (Means for Solving the Problems) The present invention provides a fine inorganic fiber material surface-treated with at least one of natural rubber and/or synthetic rubber, a mercapto group-containing silane compound, and a sulfide compound containing a mercapto group, and a non-sulfur-based additive. The present invention relates to a rubber composition characterized by containing a sulfurizing agent, and a rubber composition further blended with a crosslinkable moamer. Various known rubbers can be used as the rubber component of the present invention, such as natural rubber (NR), isoprene rubber (IRE), styrene-butadiene rubber (SBR), nitrile rubber (NBR), butadiene rubber (BR), chloro Propylene rubber (CR), rubber rubber (ITR), acrylic rubber (AR), urethane rubber (tJR), silicone rubber (SiR), fluororubber (FR), ethylene propylene rubber (EPR), chlorosulfonated polyethylene (C3M), ethylene acetate rubber (EVA), chlorinated polyethylene (CPE), polyimbutylene (pr
B), alphine rubber (AL), polyester rubber (E
S RL epichlorohydrin rubber (ECR), chlorinated butyl rubber (CTR), nitrile isobutylene rubber (N
IR), etc. In the present invention, fine irregular fiber material refers to a fiber length of 1μ11
~11, exhibiting a fiber shape with an aspect ratio of 5 to 1000, preferably an average fiber length of 5 to 300μ, and an aspect ratio of 10 to 300, and those in this range have excellent reinforcing properties and homogeneous dispersibility. , a homogeneous intensity distribution is obtained. Inorganic twisters are preferred as the fine inorganic fiber material of the present invention. Main examples of fine inorganic am materials according to the present invention include alumina fiber, silicic acid #f1. Tsuji, titania YL fiber, magnenium silicate fiber, calcium silicate fiber, calcium sulfate fiber, silicon carbide fiber, titanium carbide fiber, boron carbide fiber, boron titanium 4a fiber, titanium titanium W1. fiber, borated carbon fiber, borated carbon fiber 4I,
Silicon boride fiber, titanium boride fiber, sodium titanate fiber, potassium titanate fiber, lithium titanate fiber,
Calcium titanate fiber, magnesium titanate fiber,
Barium titanate fibers, etc., have excellent reinforcing properties, heat resistance, and white skin, and can be easily manufactured to the desired color tone, with fine and homogeneous A-fiber length, and are homogeneously dispersible as composite materials. A suitable material is potassium titanate fiber, which is rich in potassium titanate. Potassium titanate fiber has the general formula K 20 ・nT io 2 or the general formula 20・1]T
10□・1/2l-120 (in both formulas, n is 2 to 8
(representing an integer of ), specific examples include potassium tetratitanate fiber, potassium hexatitanate fiber, potassium octitanate fiber, etc., and they may be used alone. Two or more types may be mixed and used. The average am diameter of these potassium titanate fibers is 0.1~
It is preferable that the average fiber length per 2 μm is 5 to 100 μm and the spectral ratio is 10 to 200. Here, the average fiber diameter and the average fiber length are the average values of the values measured for at least 10 or more fibers per field, examined using a scanning electron microscope in at least 5 fields of view, and the aspect ratio. The ratio means the value obtained by dividing the average fiber mi of such N&fibers by the average fiber diameter. In the present invention, a typical example of a mercapto group-containing silane compound for treating the surface of a fine inorganic fiber material is the general formula % (R' is a substituted or unsubstituted divalent hydrocarbon group having 2 to 6 carbon atoms, R2 is a substituted or unsubstituted monovalent hydrocarbon group, X is a hydrolyzable group, a is an integer of 1 to 3, b is an integer of 0 to 2,
1≦(a+b)≦3. ). Examples of R1 include an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, and a hexamethylene group, with an ethylene group and a trimethylene group being preferred, and a trimethylene group being particularly preferred. R2 is an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, an octyl group, an allyl group, a dodecyl group, an octadecyl group; a vinyl group,
Alkenyl groups such as allyl; aryl groups such as phenyl and tolyl; aralkyl groups such as benzyl, β-phenylethyl, and β-phenylpropyl; β
-cyanoethyl group, arcloprobyl group, 3°3.3
-) Substituted hydrocarbon groups such as lifluoropropyl group and chlorophenyl group are exemplified, and are variously selected depending on the type of rubber component and purpose of use.
Aryl groups and aralkyl groups are effective for rubber components containing aromatic rings, and substituted hydrocarbon groups are effective for rubber components containing halogens, nitriles, etc. a flukoxyl group such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group; a flukoxyalkoxy group such as a β-methoxyethoxy group, a β-ethoxyethoxy group, a β-butoxyethoxy group; an isopropenyloxy group di/oxy groups such as dimethylketooximado group, methylethylketooximado group; ami7 groups such as diethyl7mi7 group, dibutylami7 group; aminoxy group such as noethyl7minoxy group; acetoxy group, octa 7 such as noyloxy group
Siloxy group: An amide group such as N-methyl 7cetamido group is exemplified. Among these, lower alkoxy groups having 1 to 4 carbon atoms are preferred because they have excellent surface reactivity with fine black iso fiber materials, and among these, metquin groups, which have particularly good reactivity, are preferred. a is an integer of 1 to 3, preferably less than 2 on average, and b is an integer of 0 to 2, preferably 1 or less on average. This is because if a and b are too large, the number of hydrolyzable groups will decrease and the reactivity with the inorganic fiber substance will be reduced, and if a is too small, the effect of the mercapto group on the rubber component will be reduced. Preferably, the average value of a is adjusted to 1, and the average value of b is adjusted to less than 1. Typical examples of silyl group-containing sulfide compounds include the general formula (R3 is a substituted or unsubstituted monovalent hydrocarbon group that is the same or different from each other, R4 is a substituted or unsubstituted monovalent hydrocarbon group that is the same or different from each other, and has 2 carbon atoms) to 4 hydrocarbon groups, Y is a hydrolyzable group, C is an integer of 0 to 2, and n is an integer of 1 to 6). R3 is an alkyl group such as a 7tyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, an octyl group, a decyl group, a dodecyl group, an octadecyl group; a vinyl group,
Alkenyl groups such as allyl; aryl groups such as phenyl and tolyl; aralkyl groups such as benzyl, β-phenylethyl, and β-phenylpropyl; β
-thia7ethyl group, γ-chloropropyl group, 3t3.3
-) Substituted hydrocarbon groups such as lifluoropropyl group and chlorophenyl group are exemplified, and various types are selected depending on the type of rubber component and purpose of use. Aralkyl groups are effective for rubber components containing aromatic rings, and substituted hydrocarbon groups are effective for rubber components containing halogens, nitriles, etc. Examples of R4 include an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, and a hexamethylene group, with an ethylene group and a trimethylene group being preferred, and a trimethylene group being particularly preferred. Y is a hydrolyzable group bonded to a silicon atom, such as an alkoxyl group such as a methoxy group, an ethquin group, a propoxy group, a butoxy group; a β-nodoxyethoxy group, a β-ethoxyethoxy group, a β-butoxyethoxy group, etc. Flukoxyalkoxy group; Enoxy group such as isopropenyloxy group; Ketooximado group such as dimethylketooximado group, methylethylketooximado group; Ami7 group such as butylami 7 group, butylami 7 group; aminoxy such as butylami 7 group Group; 7 such as acetoxy group, octaphyloxy group, etc.
Siloxy group: An amide group such as N-methylacetamide group is exemplified. Among these, lower alkoxy groups having 1 to 4 carbon atoms are preferred because they have excellent surface reactivity with fine inorganic fiber materials, and among these, propoxy groups are particularly preferred because they are easily synthesized and are stable compounds. C is an integer of O to 2, and one molecule of the silyl group-containing sulfide compound represented by the general formula (II) contains at least one, preferably two, hydrolyzable groups that react with the surface of the inorganic fiber material. It is desirable that C is less than 2 on average. n is an integer from 1 to 6, preferably from 2 to 4 on average in view of ease of synthesis, affinity with rubber, and inhibition of vulcanization. In the present invention, the surface of a fine inorganic fiber material is treated with one or a mixture of two or more of a mercapto group-containing silane compound and/or a silyl group-containing sulfide compound (hereinafter abbreviated as the surface treatment agent of the present invention). The amount of the surface treatment agent of the present invention used is generally about 0.05% based on the fine inorganic fiber material.
The content is preferably in the range of ~10% by weight; in this range, the surface of the fine inorganic fiber material is sufficiently improved, and the physical properties of the rubber composition are improved without causing vulcanization inhibition during vulcanization, which will be described later. That's a big deal. The treatment method using the surface treatment agent of the present invention may be any of the commonly used surface treatment methods, such as spraying the surface treatment agent of the present invention or its diluted solution onto the surface of the fine inorganic a-substance. A method of homogeneously mixing with the fine inorganic fiber material or a method of impregnation treatment can be adopted, and after the surface treatment agent of the present invention is uniformly adhered to the surface of the fine inorganic fiber material, heating drying, hydrolysis, etc. are performed. Accordingly, the surface treatment agent of the present invention can be uniformly fixed to the surface of the fine inorganic substance. The surface treatment agent of the present invention contains sulfur element in the molecule,
In particular, terminal mercapto compounds are sulfur-containing compounds that inhibit vulcanization during peroxide-based vulcanization and have been thought to reduce the physical properties of rubber. Although it is not clear, the effect is remarkable, and the inorganic fiber material and the rubber material are strongly bonded, and the inorganic fiber material and the rubber material are strongly bonded, and the inorganic fiber material and the rubber material are strongly bonded.
The sliding phenomenon at the interface between the fibrous filler and rubber matrix, which is thought to be the cause of the deterioration of physical properties in composite materials, is suppressed.
A rubber composition with high hardness and high compressive strength is obtained. In the present invention, unsaturated carboxylic acids, salts thereof, other unsaturated vinyl compounds, etc. can be used as crosslinking monomers. Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, 2-acetamide/acrylic acid, β,
β-no/tacrylic acid, ethacrylic acid, a-chloroacrylic acid, cinnamic acid, acotinic acid, 2-ethyl-3-propylacrylic acid, crotonic acid, ami7-crotonic acid, 7-side phosphohydroxyethyl (meth)acrylate, β-acryloxypropionic acid, 2-butene-1,4-nocarboxylic acid, sorbic acid, acetylcarboxylic acid, N-butylmaleamic acid, 7-malic acid, maleic acid, chlormaleic acid, non-n-butylmaleamic acid ,N. N-no/tyl maleamic acid, N-ethyl male 7) acid,
N-Phenylmale 7miPl? ! , dichloromaleic acid,
Dihydroxymaleic acid, allylarsonic acid, chloroendic acid, itaconic acid, benzoyl acrylic acid, etc. can be mentioned, and other unsaturated vinyl compounds include, for example, vinyl acetate, vinyl propionate, vinyl caproate, styrene, vinyl toluene, Vinyl compounds such as divinylbenzene; Furkyl esters such as acrylic acid and methacrylic acid; (meth)acrylic N1 derivatives such as (meth)acrylonitrile, (meth)acrylamide, and glycidyl (meth)acrylate; Various compounds such as triallylisocyanurate can be exemplified. Among these, acrylic acid, methacrylic acid, cinnamic acid, hepcotic acid, crotonic acid, itaconic acid and benzoyl acrylic acid are preferred; these compounds can be used alone or in a mixture of two or more. Metal salts of the unsaturated carboxylic acids mentioned above can also be used; typical examples of such metals include lithium,
Sodium, potassium, strontium, zinc, magnesium, calcium, barium, cadmium, lead, zirconium, beryllium, copper, aluminum, tin, iron,
Any one or a mixture of two or more of antimony, bismuth, molybdenum, tungsten, nickel, etc. can be used, and divalent or higher metal salts are preferred because they increase the crosslinking effect, are easily available, and have low toxicity. Among them, calcium, zinc, magnesium, zirconium, etc. are preferred. In addition to being used as metal salts of unsaturated carboxylic acids reacted with unsaturated carboxylic acids in advance, these metal species can also be used in combination with unsaturated carboxylic acids and these metals, metal oxides, hydroxides,
Carbonates, etc. may be mixed separately into the rubber component and reacted in the mixed system to form a metal salt.In the present invention, the amount of the crosslinking monomer to be used is not particularly limited, but 0. 1 to 50 parts by weight, preferably 1 to 15i
1 (11 parts), and within this range, the hardness of impact resilience can be easily adjusted. Examples of the non-sulfur vulcanizing agent of the present invention include metal oxides such as magnesium oxide, lead oxide, and zinc oxide. ; Crosslinkable resins such as 7-el resin, melamine formaldehyde Iffl?, urethane resin, polyester resin, polyamide resin, epoxy resin, and low molecular weight products or modified products thereof; diacetyl peroxide, dibenzoyl peroxide, capril peroxide, ) (p-chlorobenzoyl) peroxide V, nodeca/yl peroxide, (2,4-dichlorobenzoyl) peroxide,
Diisobutyl peroxide, diiso7nanyl peroxide, dilauroyl peroxide, diacetyl peroxide, diacetyl peroxide, di(β-carboxypropinoyl) peroxide, methyl ethyl ketone peroxide, cyclohexanone peroxide, dihydroxydimethyl-dioxacyclo penkun, t-butyl peroxide, t-butyl peroxy (2-ethylhexanony)), 1-butyl peroxyisobutyrate, 0.0-1-butyl-0-isopropyl monoperoxy carbonate,

[-butyl peroxy pivalate, dimethyl di(benzoyl peroxy) hexane, t-butyl peroxy (2-ethyl butyrate), di-t-butyl peroxide, dicumyl peroxide, cumethyl bis(benzoyl peroxy) Examples include organic peroxides such as hexane, t-butylhydroperoxide, cumylhydroperoxide, bis(t-butylperoxy)trimethylcyclohexane, and n-butylbis(L-butylperoxy)valerate. Among these, dicumyl peroxide, cumyl hydroperoxide, t-butyl peroxide,
Dibutyl peroxide, bis(1-butylperoxy)trimethylcyclohexane, n-butylbis(t-butylperoxy)valylate, etc. are suitable because vulcanization proceeds homogeneously due to the relationship between vulcanization temperature and half-life. . These non-sulfur vulcanizing agents can be used alone or as a mixture of two or more, and the amount used is arbitrarily selected depending on the type of rubber used, the purpose of use of the rubber composition, etc. Preferably, it is used in an amount of about 0.01 to 15% by weight based on the ingredients. In the present invention, it is possible to add various known additives,
For example, vulcanization retainers, vulcanization retarders, anti-aging agents, plasticizers,
A tackifier, a tackifier, an anti-tack agent, a foaming M1 dispersant, a dusting agent, a mold release agent, a solvent, a softener, and the like can be added as necessary. Furthermore, in the present invention, clay materials such as carbon black, magnesium carbonate, zinc oxide, calcium carbonate, barium sulfate, aluminum hydroxide, aluminum oxide, silica powder, titanium oxide, talc, clay, diatomaceous earth, and kaolin are used as reinforcing materials. Various inorganic fillers such as powders and arbitrary pigments and dyes as coloring agents can also be used together. Any resin that is commonly used as a hexacarbonaceous modifier, such as coumaron indene resin, hexafluoride resin, etc. 7
A mixture of polyester resin, polystyrene resin, acrylic resin, polyamide resin, epoxy resin, urethane resin, polyolefin resin, etc. may be used. Furthermore, in the present invention, commonly used long fiber reinforcing agents such as inorganic fibers such as glass fibers, carbon fibers, metal fibers, quartz fibers, and ceramic A fibers; nylon fibers, vinylon fibers, polyester fibers, aromatic polyamide fibers, and polyimide fibers are also used. '#a, m, organic fibers such as aromatic polyetheramide fibers can also be used in combination. The composition of the present invention includes a rubber component, a fine sand-free #a fiber material treated with the above-mentioned surface treatment agent of the present invention, an optional crosslinking monomer, and a non-sulfur vulcanizing agent, and further, if necessary, It is obtained by kneading various additives, auxiliary agents, etc. to be added in a conventional manner. Vulcanization of the composition of the present invention can also be carried out by a conventional method, and the vulcanization temperature is generally in the range of about 80 to 180°C, and the vulcanization time is preferably about 5 to 60 minutes. The rubber composition of the present invention can be used for various purposes, but
For example, it can be used in industrial materials such as rubber rolls, sporting goods such as shoe soles, golf balls and baseball balls, and other fields such as electronic equipment, communication equipment, and the chemical industry. (Example) Examples and comparative examples will be described below. Examples 1 to 18 and Comparative Examples 1 to 7 Each component listed in Table 1 was mixed with S! : The entire amount of seeds was added, mixed at 60 to 100°C for 10 minutes, the contents were cooled to 60 to 70°C, and then a vulcanizing agent was added to obtain the composition of the present invention. Using this composition, the weight was adjusted and kneaded so that each ball weighed 45 g, and then vulcanized in a golf ball mold at 150 ± 5°C for 30 minutes to make a golf ball, and its physical properties were measured. . The results are shown in Table 1. Examples 19 to 36 and Comparative Example 8 to] 4 @2 An experiment was conducted in the same manner as in Example 1, except that each component listed in Table 2 was used. The results are shown in Table 2. In addition, in the table, treated product A is potassium titanate (untreated product) is human urine chemistry (
Co., Ltd., Teismo D treated with 1% bis(3-triethoxysilylpropyl)tetrasulfide, and treated product B is Teismo D treated with 1% γ-mercaptopropyltrimethoxysilane. , Treated product C is Teismo D treated with 1% γ-glycidoxypropyltrimethoxysilane, and treated product is Teismo D treated with 1% 7-flucapdopropyltriethoxysilane. Treated product E is Teismo D treated with 1% bis(3-tritoxysilylprobyl)tetrasulfide, and Treated product F is silicon carbide whisker [Toka Whisker, manufactured by Tokai Carbon] treated with γ-mercapto. Treated product G is a product treated with 1% propyl ethoxysilane, and treated product G is a product treated with Toka whisker using 1% bis(3-triethoxysilylpropyl)tetrasulfide.

Claims (4)

[Claims] (1) It is characterized by containing a fine inorganic fiber material surface-treated with at least one of natural rubber and/or synthetic rubber, a mercapto group-containing silane compound, and a silyl group-containing sulfide compound, and a non-sulfur-based vulcanizing agent. Rubber composition. (2) a fine inorganic fiber material surface-treated with at least one of natural rubber and/or synthetic rubber, a mercapto group-containing silane compound, and a silyl group-containing sulfide compound;
A rubber composition comprising a crosslinking monomer and a non-sulfur vulcanizing agent. (3) The mercapto group-containing silane compound has the general formula ▲mathematical formula,
Chemical formulas, tables, etc. are available▼(I) (R^1 is a substituted or unsubstituted divalent hydrocarbon group having 2 to 6 carbon atoms, R^2 is a substituted or unsubstituted monovalent hydrocarbon group,
X is a hydrolyzable group, a is an integer of 1 to 3, b is an integer of 0 to 2, and 1≦(a+b)≦3. ) The rubber composition according to claim 1 or 2, which is a compound represented by: (4) The silyl group-containing sulfide compound has a general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (II) (R^3 is the same or different substituted or unsubstituted 1
R^4 is the same or different substituted or unsubstituted hydrocarbon group having 2 to 4 carbon atoms, Y is a hydrolyzable group, c is an integer of 0 to 2, and n is 1 to 6. is an integer. )
Claim 1 or 2 which is a compound represented by
The rubber composition described in .