KR101151425B1 - Modified calcium carbonate containing rubber compositions - Google Patents

Abstract

With respect to 100 parts by weight of at least one rubber selected from natural rubber and synthetic rubber, any one selected from the group consisting of (1) carbon black, (2) silica, and (3) a mixture of carbon black and silica as component 1 At least one selected from a rubber composition comprising 20 to 100 parts by weight of one, and 0.5 to 20 parts by weight of a modified calcium carbonate having a silica layer and a silane coupling agent layer as components 2, and natural rubber and synthetic rubber. Any one of (1) to (3) selected from the group consisting of (1) carbon black, (2) silica, and (3) a mixture of carbon black and silica as component 1 based on 100 parts by weight of one rubber 20-100 weight part, the organic acid obtained by processing with at least 1 sort (s) chosen from the group which consists of (i) a silica layer, (ii) fatty acid, a fatty acid salt, fatty acid ester, resin acid, a resin acid salt, and resin acid ester as a component 2, A rubber composition comprising 0.5 parts by weight or more and less than 20 parts by weight of a modified calcium carbonate having a layer and (iii) a silane coupling agent layer.

Rubber composition, modified calcium carbonate, silica, carbon black, organic acid, silane coupling agent

Description

Modified calcium carbonate-containing rubber composition {MODIFIED CALCIUM CARBONATE CONTAINING RUBBER COMPOSITIONS}

The present invention relates to a rubber composition excellent in both unvulcanized rubber properties and rubber properties. It also relates to a rubber product obtained from the rubber composition.

Conventionally, carbon black is mainly used as a filler of a rubber composition for tires. In recent years, in order to satisfy the demand of low fuel consumption in the automobile industry, the replacement of a part of carbon black with a silica-based filler, especially silica, has been considered.

However, rubber compositions using carbon black and silica in combination with (1) have a higher viscosity of unvulcanized rubber and (2) have higher self-aggregation properties of silica than rubber compositions containing only carbon black, and thus are not easily dispersed. 3) There is a problem that the Mohs hardness of silica is high and wear of processing machines such as rubber kneaders and molding machines may be severe. Moreover, in order to express tire characteristics comparable to the rubber composition containing only carbon black, a rubber composition using carbon black and silica in combination with silica requires a large amount of an expensive silane coupling agent, which is problematic in terms of cost. .

As a means to solve such a problem, it has been attempted to blend a filler such as calcium carbonate into the polymer composition (Japanese Patent Laid-Open No. 11-269307, Japanese Patent Laid-Open No. 09-194634, Japanese Patent Laid-Open No. 09-077915). See Japanese Patent Application Laid-Open No. 09-150606, Japanese Patent Application Laid-Open No. 10-087896, etc.).

Calcium carbonate is widely used as an extender and reinforcing agent for rubber, and the rubber composition containing calcium carbonate has a low viscosity in the unvulcanized state and has roll-sticking properties as compared to the rubber composition containing silica. There is a good advantage. In addition, since calcium carbonate has a weak alkaline pH, the rubber composition containing calcium carbonate also has the advantage of not being vulcanized.

However, when calcium carbonate is added to the rubber composition as it is, there is a problem that the mechanical properties of the rubber composition are deteriorated.

The main object of the present invention is to obtain a rubber composition excellent in both unvulcanized rubber properties and vulcanized rubber properties.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in order to solve the said problem, the rubber obtained by mix | blending specific amount of carbon black and / or a silica, and the modified calcium carbonate which has a specific structure to at least 1 sort (s) of rubber chosen from a natural rubber and a synthetic rubber. It was found that the composition had the desired physical properties, and the intensive examination was repeated to complete the present invention.

That is, the present invention relates to the following rubber compositions and rubber products.

Item 1. A rubber composition comprising the following components 1 and 2 with respect to 100 parts by weight of at least one rubber selected from natural rubber and synthetic rubber;

Component 1: 20-100 parts by weight of any one of (1) to (3) selected from the group consisting of (1) carbon black, (2) silica, and (3) a mixture of carbon black and silica,

Component 2: 0.5 weight part or more and less than 20 weight part of modified calcium carbonate which has a silica layer and a silane coupling agent layer.

Item 2. A rubber composition comprising the following components 1 and 2 with respect to 100 parts by weight of at least one rubber selected from natural rubber and synthetic rubber;

Component 1: 20-100 parts by weight of any one of (1) to (3) selected from the group consisting of (1) carbon black, (2) silica and (3) a mixture of carbon black and silica,

Component 2: (i) Silica layer, (ii) Fatty acid, fatty acid ester, fatty acid ester, resin acid, resin acid salt, and organic acid layer obtained by processing with at least 1 sort (s) selected from the group consisting of resin acid ester, and (iv) silane 0.5 weight part or more and less than 20 weight part of modified calcium carbonate which has a coupling agent layer.

Preferably, with respect to 100 parts by weight of at least one rubber selected from natural rubber and synthetic rubber,

Component 1: 20-100 parts by weight of carbon black and

Component 2: (i) Silica layer, (ii) Fatty acid, fatty acid ester, fatty acid ester, resin acid, resin acid salt, and organic acid layer obtained by processing with at least 1 sort (s) selected from the group consisting of resin acid ester, and (iv) silane 0.5-18 weight part of modified calcium carbonate which has a coupling agent layer

Rubber composition containing a.

Item 3. The rubber composition according to Item 1 or 2, wherein component 1 is a mixture of (3) carbon black and silica, wherein the mixing ratio of carbon black to silica is 0.5: 99.5 to 99.5 to 0.5 by weight.

Item 4. The rubber composition according to any one of Items 1 or 2, wherein component 1 is (2) silica and further contains component 3 below;

Component 3: 0.1-30 weight% of a silane coupling agent with respect to the compounding quantity of silica.

Preferably, with respect to 100 parts by weight of at least one rubber selected from natural rubber and synthetic rubber,

Component 1: 20 to 80 parts by weight of silica,

Component 2: (i) Silica layer, (ii) Fatty acid, fatty acid ester, fatty acid ester, resin acid, resin acid salt, and organic acid layer obtained by processing with at least 1 sort (s) selected from the group consisting of resin acid ester, and (iv) silane 0.5-15 weight part of modified calcium carbonate which has a coupling agent layer, and

Component 3: 0.1-30 weight% of silane coupling agents with respect to the compounding quantity of a silica

Rubber composition containing a.

Item 5. The rubber composition according to any one of Items 1 to 3, wherein component 1 is a mixture of (3) carbon black and silica, and further contains component 3 below;

Component 3: 0.1-30 weight% of a silane coupling agent with respect to the compounding quantity of silica.

Item 6. A rubber product obtained by molding the rubber composition according to any one of items 1 to 5.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated concretely. In addition, in this specification, "%" and "part" represent a "weight%" and a "weight part" unless there is particular notice.

Rubber

As the rubber, at least one rubber selected from natural rubber and synthetic rubber is used.

The natural rubber is a rubber-like high molecular material obtained from a natural plant, and the type thereof is not particularly limited as long as it has a cis-1,4-polyisoprene structure chemically.

As the synthetic rubber, both a diene rubber and a diene rubber can be used.

Specific examples of the synthetic rubber that can be used include cis-1,4-polyisoprene, emulsion polymerization styrenebutadiene copolymer, solution polymerization styrenebutadiene copolymer, low cis-1,4-polybutadiene, and high ( High cis-1,4-polybutadiene, ethylene-propylene-diene copolymer, chloroprene, butyl halide rubber, acrylonitrile-butadiene rubber, ethylene-propylene copolymer, butyl rubber, urethane rubber, silicone rubber, fluorine rubber, Chlorosulfonated polyethylene, chlorinated polyethylene, epichlorohydrin rubber, acrylic rubber, ethyl acrylate copolymer, ethylene vinyl acetate copolymer, nitrile rubber, hydrogenated nitrile rubber, epoxidized natural rubber, and the like.

Among the above-mentioned rubbers, natural rubber, cis-1,4-polyisoprene, emulsion polymerization styrenebutadiene copolymer, solution polymerization styrenebutadiene copolymer, low cis-1,4-polybutadiene, and high sheath -1,4-polybutadiene may be particularly suitably used.

Rubber may be used individually by 1 type selected from the above-mentioned natural rubber or synthetic rubber, or may mix and use 2 or more types. The mixing ratio can be appropriately set in accordance with required characteristics and the like.

In addition, for the purpose of improving workability and the like, an oil extended rubber in which an extender oil is premixed with the rubber may be used.

Ingredient 1

Component 1 blended with the rubber composition of the present invention is one of (1) carbon black alone, (2) silica alone, or (3) a mixture of carbon black and silica.

The blending ratio with respect to the rubber composition of component 1 is 20-100 weight part with respect to 100 weight part of rubber, and it adjusts suitably in order to acquire desired physical property.

Hereinafter, it demonstrates dividing into the case of (1)-(3).

(1) carbon black

As the carbon black used in the present invention, those commonly used for rubber reinforcement can be used.

Although the BET specific surface area of carbon black is not specifically limited, The BET specific surface area by nitrogen adsorption method is 20 m <2> / g or more, Preferably it is 20-220 m <2> / g, Furthermore, 20-200 m <2> / g is suitable. Can be used. When used for applications requiring reinforcement, such as tire treads, the BET specific surface area by nitrogen adsorption method is especially 70 m 2 / g or more, preferably 70 to 220 m 2 / g, more 70 to 200 m 2 / g is appropriately used.

The BET specific surface area of the carbon black is in the above range, whereby a rubber composition having a good dispersibility of carbon black and excellent in tensile properties, tear strength, abrasion resistance, and the like is obtained.

When component 1 is (1) carbon black alone, the compounding quantity of carbon black is about 20-100 weight part with respect to 100 weight part of rubber, Preferably it is about 40-90 weight part, More preferably, it is about 40-80 weight part to be.

When the blending amount of the carbon black is in the above range, a rubber composition is obtained which is not deteriorated in workability due to an increase in Mooney viscosity, and which is particularly excellent in wear resistance, tensile properties and the like.

(2) silica

As silica used by this invention, what is used for rubber reinforcement can be used. Specific examples of silica include wet silica, dry silica and the like.

Although the BET specific surface area of silica is not specifically limited, The BET specific surface area by nitrogen adsorption method is 20 m <2> / g or more, More preferably, it is 20-400 m <2> / g, More preferably, it is 30-300 m <2> / g Is used appropriately.

The BET specific surface area of silica is preferably in the above range in that the rubber composition is excellent in dispersibility of silica and excellent in tensile properties, tear strength, abrasion resistance, and the like.

When component 1 is (2) silica alone, the compounding quantity of silica is 20-100 weight part with respect to 100 weight part of rubber, Preferably it is 40-90 weight part, More preferably, it is about 40-80 weight part.

When the compounding quantity of silica is in the said range, the rubber composition which is excellent in abrasion resistance, tensile property, etc. is obtained without the fall of the workability by raise of a Mooney viscosity.

(3) mixture of carbon black and silica

As a mixture of (3) carbon black and silica used by this invention, what mixed said (1) carbon black and said (2) silica according to a well-known method is used.

When component 1 is a mixture of (3) carbon black and silica, the mixing ratio of carbon black and silica is 0.5: 99.5 to 99.5: 0.5, preferably 10:90 to 90:10, more preferably 30: by weight. 70-70: 30.

When component 1 is a mixture of (3) carbon black and silica, the compounding quantity of component 1 is 20-100 weight part with respect to 100 weight part of rubber, Preferably it is about 40-90 weight part.

When the compounding quantity of the mixture of carbon black and silica is in the said range, there exists no fall of workability by the rise of a Mooney viscosity, and the rubber composition which is especially excellent in abrasion resistance, tensile characteristics, etc. is obtained.

Component 2: Modified Calcium Carbonate

The rubber composition of the present invention contains modified calcium carbonate as component 2.

The modified calcium carbonate used in the present invention is a modified calcium carbonate in which two layers of a silica layer and a silane coupling agent layer are added to calcium carbonate as a raw material, or a silica layer, a fatty acid, a fatty acid salt, a fatty acid ester, a resin acid and a calcium carbonate as a raw material. And modified calcium carbonate to which three layers of an organic acid layer and a silane coupling agent layer obtained by treating with at least one selected from the group consisting of resin resins and resin acid esters are added.

Here, the "layer" refers to all or part of the surface of the raw calcium carbonate or partially modified calcium carbonate (ie, partially modified calcium carbonate having one or two layers selected from a silica layer, a silane coupling agent layer and an organic acid layer). What is necessary is just to cover and it does not necessarily need to cover the whole surface continuously.

In the modified calcium carbonate of the present invention, the surface structure is in the order of (1) a silica layer, an organic acid layer, a portion laminated from the inside to the outside in the order of the silane coupling agent layer, and (2) the silica layer and the silane coupling agent layer. (3) A layer laminated from the inside to the outside, (3) the silica layer, the part laminated from the inside to the outside in the order of the organic acid layer, and (4) the silica layer, the organic acid layer and the silane coupling agent layer are present individually (alone). The state may be mixed.

The thickness of each layer can be suitably set for the purpose of obtaining desired physical properties.

Raw Material Calcium Carbonate

There is no restriction | limiting in particular in the kind of calcium carbonate used as a raw material of the modified calcium carbonate used by this invention, A well-known calcium carbonate, for example, heavy calcium carbonate, synthetic (precipitable) calcium carbonate, etc. can be used.

Heavy calcium carbonate is a well-known dry or wet type of calcium carbonate that is naturally produced using roller mills, high-speed rotary mills (impact shear mills), container driving medium mills (ball mills), media stirring mills, planetary ball mills, jet mills, and the like. It can be prepared by grinding by the grinding method of.

Synthetic (precipitating) calcium carbonate can be obtained according to known methods such as lime oil-carbonate gas reaction method, calcium chloride-soda ash reaction method, lime oil-soda ash reaction method and the like. As an example of the lime oil-carbon gas reaction method, the limestone raw material is burned with coke or petroleum fuel (heavy oil or light oil), natural gas, LPG, etc. to make quicklime, and the quicklime is hydrated to form a calcium hydroxide slurry, which is then burned. Calcium carbonate can be obtained by bubbling and reacting carbon dioxide generated at the time. By setting the conditions at the time of carbon dioxide reaction, the microparticles | fine-particles of a desired submicron level can be obtained.

In addition to this, a zinc salt which becomes zinc hydroxide by hydrolysis is added to the calcium hydroxide slurry, and at the same time, a method of producing calcium carbonate finer than that of the calcium carbonate by bubbling carbon dioxide and reacting can also be applied. 401044).

Although the BET specific surface area of raw material calcium carbonate can be set suitably, it is about 5-120 m <2> / g normally, Preferably it is about 20-110 m <2> / g, More preferably, it is about 50-100 m <2> / g.

When the BET specific surface area of raw material calcium carbonate is too large, it is necessary to increase the usage-amount of fatty acid, fatty acid salt, fatty acid ester, resin acid, resin acid salt, or resin acid ester. Fatty acid, fatty acid salt, fatty acid ester, resin acid, resin acid salt and resin acid ester also act as a softener, and thus, the reinforcing effect on rubber may be impaired. On the other hand, when the BET specific surface area of raw material calcium carbonate is too small, there exists a possibility that the reinforcement effect at the time of mix | blending with rubber may fall.

The particle diameter of the raw material calcium carbonate can be appropriately set within the range showing the effect of the present invention, but the size of the primary particle diameter of the raw material calcium carbonate particles when observed with a scanning electron microscope is preferably about 0.01 to 0.5 μm, It is more preferable that it is about 0.02-0.4 micrometer.

? Silica Layer

The silica layer is a layer obtained by treating with silica hydrosol. Silica in silica hydrosol can adhere to calcium carbonate almost quantitatively.

As a silica hydrosol, what was manufactured according to a well-known method can be used. For example, silica hydrosol by acid decomposition can be used. In addition, an amorphous silica hydrosol produced by adding an inorganic acid such as hydrochloric acid or sulfuric acid, an aluminum sulfate or an organic acid such as acetic acid or acrylic acid, or other acidic substances such as carbon dioxide or sulfur dioxide can be used in the sodium silicate solution. Alternatively, silica hydrosol produced by dialysis can be used by allowing sodium silicate to pass through the semipermeable membrane. Moreover, the silica hydrosol produced | generated by the ion exchange method using an ion exchange resin can be used.

As a method for treating calcium carbonate with silica hydrosol, for example, an aqueous solution of sodium silicate in an appropriate concentration is added to a calcium carbonate slurry, and an acidic substance such as an inorganic acid or an organic acid is added dropwise while stirring, and an active silica hydrosol is produced. The method of treating a calcium carbonate surface is mentioned. Moreover, the method of processing the surface of a calcium carbonate by adding the silica hydrosol previously prepared to a calcium carbonate slurry and stirring strongly can also be used.

As a calcium carbonate slurry, the thing of 0.2-20% of solid content concentration (calcium carbonate concentration), Furthermore, about 1-15% is used suitably. As the aqueous sodium silicate solution, one having a concentration of about 1 to 40% is suitably used as the amount of silica.

The adhesion amount of silica to calcium carbonate can be appropriately prepared according to the BET specific surface area of calcium carbonate, etc., but is usually about 0.5 to 15 parts by weight, preferably about 1 to 12 parts by weight based on 100 parts by weight of calcium carbonate as a raw material. More preferably, it is about 2-10 weight part.

The adhesion amount of silica to calcium carbonate is the amount of silica obtained from silica hydrosol attached to calcium carbonate when the calcium carbonate is treated by silica hydrosol.

When the amount of silica to calcium carbonate is too small, the reaction site sufficient to bind the silane coupling agent described later becomes small, so that there is a fear that the desired rubber properties cannot be expressed. On the other hand, if the amount of silica is too large, silica hydrosol remaining in addition to the surface of the calcium carbonate will be present in the solution. Therefore, the silica hydrosol strongly coagulates and solidifies the calcium carbonate during drying, making it difficult to grind. ) Increases. The calcium carbonate filler including such coarse particles may lower the tear strength, flex cracking resistance, and the like of the rubber composition.

? Organic Acid Layer

The organic acid layer is a layer obtained by treating with at least one selected from the group consisting of fatty acid, fatty acid salt, fatty acid ester, resin acid, resin acid salt and resin acid ester.

As a fatty acid used by this invention, a C6-C24 saturated, especially 10-20 saturated or unsaturated fatty acid is mentioned.

Examples of the saturated or unsaturated fatty acid having about 6 to 24 carbon atoms include stearic acid, palmitic acid, lauric acid, behenic acid, oleic acid, elkaic acid, and linoleic acid. In particular, stearic acid, palmitic acid, lauric acid and oleic acid are preferable. You may mix and use 2 or more types.

Examples of the salt of the fatty acid include alkali metal salts such as sodium salts and potassium salts of saturated or unsaturated fatty acids having about 6 to 24 carbon atoms, particularly 10 to 20 carbon atoms.

Moreover, as ester of a fatty acid, ester of said C6-C24, especially 10-20 saturated or unsaturated fatty acid, C6-C18 alcohol, especially C10-C18 saturated aliphatic alcohol, etc. are mentioned, for example. Can be mentioned.

Examples of the resin acid, resin acid salt and resin acid ester used in the present invention include abietinic acid or polymers thereof such as abietinic acid, dehydroabietic acid, dihydroabietic acid, and the like. , Disproportionated rosin, hydrogenated rosin, polymerized rosin, or salts thereof (e.g. alkali metal salts, alkaline earth metal salts) or esters (e.g., pentaerythritol esters, glycerol esters, hydrogenated rosin methyl of rosin Ester, triethylene glycol ester, pentaerythritol ester), etc. are mentioned. Among these, abietinic acid and dihydroabietinic acid are preferable.

As a method for treating calcium carbonate by fatty acids, fatty acid salts and / or fatty acid esters, for example, the following saponification method may be mentioned.

First, a fatty acid is saponified (it is made into metal salts, such as a Na salt and a K salt), heating in alkali metal aqueous solutions, such as NaOH aqueous solution and KOH aqueous solution, and it is brought to a solution state. Here, the concentration of the alkali metal aqueous solution is about 1 to 40%, preferably about 1 to 20%. The amount of the aqueous alkali metal solution is not particularly limited as long as it is an amount necessary for saponification of fatty acids.

Next, the aqueous suspension of the calcium carbonate on which the silica layer was formed was heated to 30 to 50 ° C in advance, and the fatty acid soap in the above solution state was added to the suspension, stirred and mixed to contain a fatty acid and / or a fatty acid salt. An organic acid layer was formed. The addition ratio of fatty acid soap to the aqueous suspension of calcium carbonate is about 10 to 70%, preferably about 10 to 50%.

In the case of using soap such as fatty acid Na by itself, an aqueous solution heated in advance is prepared, and the treatment is performed in the same manner as described above.

Moreover, the method of processing using a fatty acid without saponifying can also be used. For example, the calcium carbonate in which the silica layer was formed may be made into a powder state, and it is made to stir while heating above melting | fusing point of a fatty acid, fatty acid can be added to this, and it can stir and form a fatty acid layer.

As a treatment method by resin acid, resin acid salt, and / or resin acid ester, the same method as the said fatty acid, fatty acid salt, and / or fatty acid ester can be taken.

Specifically, the resin acid is saponified (to be a metal salt such as Na salt or K salt) while heating in an alkali metal aqueous solution such as a NaOH aqueous solution or a KOH aqueous solution to obtain a solution state. The concentration of the alkali metal aqueous solution is about 1 to 40%, preferably about 1 to 20%, and the amount of the alkali metal aqueous solution is not particularly limited as long as it is an amount necessary for saponification of the resin acid.

Next, the aqueous suspension of calcium carbonate in which the silica layer was formed was previously heated to 30-50 degreeC, the resin acid soap of the above-mentioned solution state was added to this suspension, stirred, and mixed, and the resin acid and / or resinate An organic acid layer containing is formed. The addition ratio of resinous soap to the aqueous suspension of calcium carbonate is about 10 to 70%, preferably about 10 to 50%.

When soap such as resin acid Na is used by itself, an aqueous solution of resin resin soap heated in advance is prepared and the treatment is performed in the same manner as described above.

In addition, the method of processing using resin acid without saponifying can be performed as follows. For example, the calcium carbonate in which the silica layer was formed is made into powder form, and it is made to stir while heating above the melting point of resin acid, and it adds resin acid to this, and it stirs and mixes, and forms the organic acid layer containing resin acid. .

The amount of the organic acid layer, i.e., at least one deposition amount selected from the group consisting of fatty acids, fatty acid salts, fatty acid esters, resin acids, resin salts and resin acid esters can be appropriately set within the range in which the effects of the present invention are exhibited. It is about 0.5-20 weight part normally with respect to 100 weight part of calcium carbonate used as a raw material, Preferably it is about 1-15 weight part, More preferably, it is about 2-12 weight part.

Silane coupling agent layer

The silane coupling agent layer is a layer obtained by treating with a silane coupling agent.

As the silane coupling agent used in the present invention, for example, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, β- (3,4-epoxy Cyclohexyl) ethyltrimethoxysilane, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltrimethyldiethoxysilane, γ-glyci Doxypropyltriethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane , N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltriethoxysilane, 3 -Aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N- Nyl-γ-aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, bis- (3- [triethoxysilyl] -propyl) -tetrasulfane (bis -(3- [triethoxylsilyl] -propyl) -tetrasulfane, TESPT), bis- (3- [triethoxylsilyl] -propyl) -disulfane) Can be mentioned.

Among them, γ- (2-aminoethyl) aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane and γ-mercaptopropyltri Preference is given to using methoxysilane, bis- (3- [triethoxysilyl] -propyl) -tetrasulfane and bis- (3- [triethoxysilyl] -propyl) -disulfane.

The method for treating calcium carbonate using the silane coupling agent is not particularly limited, and various methods known in the art may be used.

For example, when the calcium carbonate on which the silica layer and the organic acid layer are formed is a dry powder, the silane coupling agent layer is sprayed on the surface of the calcium carbonate by spraying the silane coupling agent with dropping or spraying while stirring the calcium carbonate powder in a mixer. You can give it. In this case, heat-drying may be carried out after surface treatment as needed.

In addition, when calcium carbonate in which a silica layer and an organic acid layer are formed is obtained in suspension, water-soluble silane coupling agent is administered to this suspension, surface treatment is carried out by adsorbing a silane coupling agent on the surface of calcium carbonate, and then the processed material is filtered. The silane coupling agent layer can be given to the surface of calcium carbonate by separating and drying. In addition, when the calcium carbonate to be treated is a suspension, a wet grinder such as a stirrer or a bead mill or a sand mill may be used to uniformly perform the treatment.

Although the adhesion amount of a silane coupling agent is adjusted suitably according to the BET specific surface area etc. of calcium carbonate to adhere, it is about 0.05-10 weight part normally, Preferably it is about 0.07-5 weight part with respect to 100 weight part of calcium carbonate used as a raw material, More preferably, it is about 0.1-3 weight part.

? Modified Calcium Carbonate

One of the modified calcium carbonates in the present invention is modified calcium carbonate having two layers of (i) a silica layer and (i) a silane coupling agent layer.

(Iii) A modified calcium carbonate having two layers of a silica layer and (iii) a silane coupling agent layer is prepared by performing a treatment with a calcium amide as a raw material with the above-mentioned silica adisol and a treatment with a silane coupling agent. can do.

The other of the modified calcium carbonate in the present invention is (i) an organic acid obtained by treating with at least one selected from the group consisting of a silica layer, (ii) a fatty acid, a fatty acid salt, a fatty acid ester, a resin acid, a resin acid salt and a resin acid ester. It is modified calcium carbonate which has three layers of a layer and (iii) a silane coupling agent layer.

The modified calcium carbonate having three layers of (i) a silica layer, (ii) an organic acid layer and (i) a silane coupling agent layer may be, for example, treated with (a) calcium carbonate by the silica hydrosol and an organic acid. It can prepare by performing the process by and a process with a silane coupling agent. Or (b) Partially modified calcium carbonate having a silica layer and (ii) an organic acid layer and a silane coupling agent can be separately blended and kneaded in a rubber composition. In the case of (b), the silane coupling agent separately mix | blended may be added as a part of component 3.

Specifically as a manufacturing method of (a), the method of having the process of the following (1)-(4) is mentioned.

(1) forming a silica layer on the surface of calcium carbonate as a raw material by adding silica hydrosol to a calcium carbonate slurry,

(2) forming an organic acid layer by adding at least one selected from the group consisting of fatty acids, fatty acid salts, fatty acid esters, resin acids, resin acid salts and resin acid esters to the calcium carbonate slurry having the silica layer,

(3) dehydrating and drying the calcium phosphate slurry in which the silica layer and the organic acid layer are formed;

(4) A step of forming a silane coupling agent layer by surface treating the obtained calcium carbonate particles with a silane coupling agent.

By this method, the modified calcium carbonate in which (i) a silica layer, (ii) an organic acid layer, and (i) a silane coupling agent layer were formed in raw material calcium carbonate is obtained.

On the other hand, specifically, the method of (b) adds partially modified calcium carbonate which has (i) a silica layer and (ii) an organic acid layer to rubber, and adds a silane coupling agent to the said rubber, and then mixes it. Can be mentioned.

Moreover, as another example, the method of adding a silane coupling agent to rubber | gum first, then adding partially modified calcium carbonate which has (i) a silica layer and (ii) organic acid layer to rubber, and mixes it is mentioned.

Silane is added to the surface of the partially calcium carbonate having the silica layer and (ii) the organic acid layer and the silane coupling agent is separately added to the rubber and then mixed with (i) the silica layer and (ii) the organic acid layer. The coupling agent adsorbs, and modified calcium carbonate having three layers of (i) a silica layer, (ii) an organic acid layer and (i) a silane coupling agent layer is formed in the rubber composition.

In the case where the partially modified calcium carbonate having the silica layer and (ii) the organic acid layer and the silane coupling agent are separately blended into the rubber composition, the amount of the silane coupling agent forming the silane coupling agent layer is 100 parts by weight of the raw material calcium carbonate. It is about 0.05-10 weight part, Preferably it is about 0.07-5 weight part, More preferably, it is about 0.1-3 weight part.

Although the BET specific surface area of modified calcium carbonate can be suitably set within the range which shows the effect of this invention, Usually, about 4-100 m <2> / g, More preferable ranges are about 15-100 m <2> / g, More preferably, 40- It is about 90 m <2> / g.

If the BET specific surface area of the modified calcium carbonate is too large, the reinforcing effect on the rubber may be impaired. On the other hand, when the BET specific surface area of the modified calcium carbonate is too small, there is a fear that the reinforcing effect when it is blended with rubber is reduced.

Although the particle diameter of the modified calcium carbonate can be appropriately set for the purpose of obtaining a desired effect, the primary particle diameter of the modified calcium carbonate particles usually observed in a scanning electron microscope is preferably about 0.01 to 0.6 µm, and 0.02 It is more preferable that it is about -0.5 micrometer.

Component 3: silane coupling agent

When mix | blending silica as component 1, it is preferable to mix | blend a silane coupling agent as a component 3 with a rubber composition.

When a mixture of silica and a silane coupling agent is used in combination, the modulus and wear resistance of the rubber composition are improved. In particular, when the rubber composition is molded into a tire as a raw material, rolling resistance and grip performance of the tire are improved.

The compounding quantity in the rubber composition of a silane coupling agent is about 0.1-30 weight% with respect to the compounding quantity of silica, Preferably it is about 1-20 weight%, More preferably, it is about 3-10 weight%. (Iii) When two layers of partially modified calcium carbonate and a silane coupling agent having a silica layer and (ii) an organic acid layer are separately added to the rubber to form three layers of modified calcium carbonate in the rubber composition, the rubber of the silane coupling agent The addition amount with respect to a composition is about 0.1-35 weight% with respect to the compounding quantity of a silica, Preferably it is about 0.1-33 weight%. Here, the compounding quantity of silica means the whole quantity of component 1, when component 1 is silica only, and the quantity of the mixing ratio of silica in component 1, when component 1 is a mixture of carbon black and silica.

As a silane coupling agent of component 3, the same thing as the silane coupling agent demonstrated in the surface treatment of the said modified calcium carbonate can be used.

Although the compounding form of a silane coupling agent is not specifically limited, It may mix | blend as a liquid form of the single substance of 100% purity, and may mix | blend as a form of a composition by impregnating into powders, such as a calcium carbonate and a silica.

Rubber composition

The rubber composition of the present invention comprises a component of the rubber component, component 1: carbon black and / or silica, and component 2: modified calcium carbonate, and component 3: silane coupling agent in the case of using a mixture of silica or silica as component 1 It is a composition containing.

You may add a well-known substance to the rubber composition of this invention as needed. Known materials include, for example, other fillers such as clay, aluminum hydroxide, hard calcium carbonate and heavy calcium carbonate, process oils such as naphthenic oil and paraffin oil, antioxidants, activators and stearic acid. Zinc oxide, wax and the like. Moreover, vulcanization agents, such as a sulfur and a vulcanization accelerator, can be mix | blended suitably.

The rubber composition of the present invention can be produced by kneading a rubber component, components 1 and 2, optionally a component 3, and other compounding agents selected according to the conventional method. You may perform heating, extrusion, etc. suitably at the time of manufacture of a rubber composition.

Various conditions of kneading, for example, the kind of kneading apparatus, the input volume, the rotation speed of the rotor, the ram pressure, the kneading temperature, the kneading time can be appropriately set according to the purpose.

There is no restriction | limiting in particular also for a kneading apparatus, It can select suitably from the well-known kneading apparatus used for kneading a rubber composition. Specifically, a Banbury mixer (registered trademark), an intermix (registered trademark), a kneader, a roll, or the like can be used. Moreover, you may use either a closed type or an open type.

Moreover, the conditions of heating and extrusion can also be set suitably. Moreover, a heating apparatus and an extrusion apparatus can also be suitably selected from a well-known thing.

EMBODIMENT OF THE INVENTION Hereinafter, the rubber composition in this invention is demonstrated further, giving a specific aspect.

Sun 1: rubber To 100 parts by weight  Component 1: Carbon Black 20 ~ 100 parts by weight Ingredient 2: Modified Calcium Carbonate 0.5 ~ 18 parts by weight  Examples of Rubber Compositions Containing

As one aspect of a rubber composition in this invention, it is carbon black as a component 1, silica layer as a component 2 with respect to 100 weight part of at least 1 sort (s) of rubber components chosen from natural 1: natural rubber and synthetic rubber, ( Ii) Modified calcium carbonate having an organic acid layer obtained by treatment with at least one selected from the group consisting of fatty acids, fatty acid salts, fatty acid esters, resin acids, resin salts and resin acid esters, and (iii) silane coupling agent layers. The composition mix | blended in quantities can be mentioned.

The rubber composition of aspect 1 contains a predetermined amount of modified calcium carbonate having at least one rubber selected from natural rubber and synthetic rubber, the carbon black and (i) silica layer, (ii) organic acid layer and (i) silane coupling agent layer. It can manufacture by kneading after mix | blending.

The order of addition (mixing) of carbon black and modified calcium carbonate is not particularly limited, and the modified calcium carbonate may be blended after the carbon black is blended, or the carbon black may be blended after the modified calcium carbonate is blended. Moreover, you may mix | blend carbon black and modified calcium carbonate simultaneously.

In the aspect 1, the compounding quantity of carbon black is about 20-100 weight part with respect to 100 weight part of rubber components, Preferably it is about 40-90 weight part, More preferably, it is about 40-80 weight part. Moreover, the compounding quantity of a modified calcium carbonate is about 0.5-18 weight part with respect to 100 weight part of rubber components, Preferably it is about 1-18 weight part, More preferably, it is about 3-15 weight part.

Embodiment 1 has a particularly good effect in that it is possible to improve the flexural resistance and the Mooney scorch time while maintaining the processability and mechanical properties of the rubber composition.

Sun 2: rubber To 100 parts by weight  Component 1: Silica 20 ~ 80 parts by weight Ingredient 2: Modified Calcium Carbonate 0.5 ~ 15 parts by weight , Component 3: with respect to the amount of silica Silane Coupling agent Examples of rubber compositions containing 0.1 to 30% by weight

As a specific aspect of the rubber composition of this invention, it is a silica as component 1, a silica layer as component 2, and (ii) fatty acid with respect to 100 weight part of at least 1 sort (s) of rubber chosen from aspect 2: natural rubber and synthetic rubber. , Modified calcium carbonate having an organic acid layer obtained by treatment with at least one selected from the group consisting of fatty acid salts, fatty acid esters, resin acids, resin salts and resin acid esters, and (iii) silane coupling agent layers, and as component 3. The composition which mix | blended the specific amount with a silane coupling agent is mentioned.

The compounding quantity of silica is about 20-80 weight part with respect to 100 weight part of rubber components, Preferably it is 40-70 weight part. Moreover, the compounding quantity of the modified calcium carbonate which has a silica layer, (ii) organic acid layer, and (iii) silane coupling agent layer is about 0.5-15 weight part with respect to 100 weight part of rubber components, Preferably it is 1-15 It is about a weight part, More preferably, it is about 3-15 weight part. The compounding quantity of a silane coupling agent is about 0.1-30 weight% with respect to the compounding quantity of silica, Preferably it is about 1-20 weight%, More preferably, it is about 3-10 weight%.

The rubber composition of aspect 2 is, for example, after blending silica and silane coupling agents with at least one rubber selected from natural rubber and synthetic rubber, (i) a silica layer, (ii) an organic acid layer, and (i) a silane coupler. It can manufacture by mix | blending and mixing modified calcium carbonate which has three layers of a ring agent layer. The compounding order of a silica, a silane coupling agent, and a modified calcium carbonate can be suitably set as desired.

In addition, the composition of aspect 2 can be manufactured using partially modified calcium carbonate which has two layers of (i) a silica layer and (ii) an organic acid layer.

For example, after mixing a silica and a silane coupling agent with at least 1 sort (s) of rubber chosen from a natural rubber and a synthetic rubber, the modified calcium carbonate which has two layers of (i) a silica layer and (ii) an organic acid layer is mix | blended. After kneading, it can manufacture. Furthermore, after mixing modified calcium carbonate having two layers of silica and (i) a silica layer and (ii) an organic acid layer to at least one rubber selected from natural rubber and synthetic rubber, a silane coupling agent is blended and kneaded. It can manufacture.

By adding and kneading the partially modified calcium carbonate having a silica layer and (ii) the organic acid layer and the silane coupling agent to the rubber composition, the silane is formed on the surface of the partially modified calcium carbonate having the silica layer and (ii) the organic acid layer. A coupling agent adsorb | sucks and the modified calcium carbonate which has three layers of (i) a silica layer, (ii) an organic acid layer, and (iii) a silane coupling agent layer is formed in a rubber composition. Thereby, the rubber composition containing modified calcium carbonate which has (i) a silica layer, (ii) an organic acid layer, and (iii) a silane coupling agent layer is manufactured.

When the two layers of partially modified calcium carbonate and silane coupling agent having (i) a silica layer and (ii) an organic acid layer are separately added to the rubber to form three layers of modified calcium carbonate in the rubber composition, the rubber of the silane coupling agent The addition amount with respect to a composition is about 0.1-35 weight% with respect to the compounding quantity of a silica, Preferably it is about 0.1-33 weight%.

Sun 2 is particularly excellent in that it can improve unvulcanized rubber properties such as Mooney scotch time without impairing the processability and mechanical properties of the rubber composition, and can also improve tear strength and permanent elongation. Effect.

Rubber product

The rubber product of the present invention is obtained by molding the rubber composition of the present invention according to a known method and vulcanizing as necessary.

Rubber products include, for example, tire treads, shoe soles, rubber belts, rubber seats (rubber plates), rubber rolls, rubber hoses, o-rings, packing of oil seals, and engine mounts. mounts, rubber bushes, dustproof rubber products such as rubber couplings, rubber seals such as window frames, foam rubber and the like.

Among these, it is especially suitably used as a tire tread.

As a molding method, press molding, injection molding, calendar processing, extrusion molding, etc. are mentioned, for example.

Examples of the vulcanization method include mold molding vulcanization (press vulcanization), plate vulcanization, direct and indirect steam vulcanization, and high frequency heating continuous vulcanization.

In addition, foaming rubber (sponge) can be obtained by molding or vulcanizing a rubber composition containing a foaming agent and a foaming aid.

Molding conditions can be appropriately set as desired. Moreover, although vulcanization conditions can be set suitably, a vulcanization temperature is about 100-190 degreeC normally.

Hereinafter, the present invention will be described in more detail with reference to Examples and Test Examples, but the present invention is not limited to these Examples.

Example  1 to 2 and Comparative example  1-4

material

In Examples 1-2 and Comparative Examples 1-4, the material described below was used.

Dielectric SBR: JSR 1778N (23.5% of bound styrene, 100 parts by weight of styrene butadiene rubber, containing 37.5 phr of extender oil), manufactured by JSR Corporation

Carbon black: Asahi # 80, ISAF, Asahi Carbon Co., Ltd.

Silica: white carbon, Nipsil AQ, Nippon Silica Industrial Co., Ltd.

Silane coupling agent: bis- (3- [triethoxysilyl] -propyl) tetrasulfane, Si69, made by Degussa

Zinc oxide: Zinc oxide grade JIS 2, manufactured by Seido Chemical Co., Ltd.

Stearic acid: Lunac S-50, manufactured by Kao Chemical Company

Naphthene oil: NP-24, manufactured by Idemitsu Kosan Co., Ltd.

Anti-aging Agent: Made by Norcrac 224, Ouchishinko Chemical Industrial Co., Ltd.

Vulcanization accelerator 1: Made by Nocceler D, Ouchishinko Chemical Industrial Co., Ltd.

Vulcanization accelerator 2: Made by Nocceler CZ, Ouchishinko Chemical Industrial Co., Ltd.

Sulfur: Powder Sulfur, manufactured by Hosoi Chemical Industry Co., Ltd.

? Modified Calcium Carbonate:

The modified calcium carbonate used in the Example and the comparative example was created as follows. The synthetic calcium carbonate slurry having a BET specific surface area of 75 m 2 / g was heated to 40 ° C. with good stirring. To this slurry was added 10% aqueous sodium silicate (sodium silicate, Wako Pure Chemical Industries, Ltd., 193-08185) aqueous solution at room temperature, followed by dropwise addition of 3.5% diluted hydrochloric acid aqueous solution while stirring to generate activated silica hydro. The surface of the calcium carbonate in the sludge was treated by sol. The amount of the aqueous sodium silicate solution and the diluted aqueous hydrochloric acid solution was adjusted so that the adhesion amount of silica obtained by silica hydrosol to the synthetic calcium carbonate was 7 parts by weight based on 100 parts by weight of the synthetic calcium carbonate.

Next, a mixture of fatty acids (wako Pure Chemical Industries, Ltd., oleic acid (159-00246), stearic acid (199-10995) containing sodium hydroxide, warmed and stirred at 90 ° C. ), Palmitic acid (165-00102)) was added, followed by dehydration, drying and grinding to prepare calcium carbonate powder (calcium carbonate A) having a silica layer and a fatty acid layer.

While stirring the obtained calcium carbonate A with a mixer, 2.0 parts by weight of bis-(-[triethoxysilyl] -propyl) -tetrasulfane (Degussa, Si69) was sprayed with respect to 100 parts by weight of the calcium carbonate A, and for 10 minutes. After stirring, the mixture was heated to dry at 100 ° C. for 60 minutes to obtain modified calcium carbonate having three layers of a silica layer, an organic acid layer, and a silane coupling agent layer.

Manufacture of rubber compositions and rubber products

The rubber compositions of Examples 1 and 2 and Comparative Examples 1 and 4 were prepared by kneading the materials shown in Table 1 or Table 2 at the ratios specified in Table 1 or Table 2. As a kneading apparatus, a volume 3 kneader kneader and 8 inches 2 rolls were used. Kneading conditions were 70% input volume (2.1 L), rotor rotation speed 30rpm, ram pressure 0.1MPa, kneading start temperature 30 ℃. The kneading time was 7 minutes.

In addition, each obtained rubber composition was subjected to press vulcanization at 160 ° C based on the optimum vulcanization time tc (90) calculated by a vulcanization tester (manufactured by JSR, Curelastometer, test temperature of 160 ° C) to a rubber sheet having a thickness of 2 mm. Or the test piece used for the evaluation method mentioned later was created.

evaluation

In order to evaluate the unvulcanized rubber properties of the rubber compositions of Examples 1-2 and Comparative Examples 1-4, the Mooney scotch time was investigated.

In addition, in order to evaluate the rubber properties after vulcanization, various molded articles (rubber sheets or test pieces) obtained by vulcanizing the rubber compositions of Examples 1 to 2 and Comparative Examples 1 to 4 were subjected to tensile tests, tear tests, hardness, permanent elongation and A test on flexural resistance was conducted.

1. Mooney Scorch Time

It measured using the Mooney viscometer by Shimadzu Corporation according to the method prescribed | regulated to JISK6300. The test temperature was 125 degreeC, the measurement was started after 1 minute of preheating, and time until the 5-point rise from minimum torque was measured.

2. Tensile test (modulus, tensile strength)

The following test items were measured at 23 ° C using a Schopper tensile strength tester according to the method specified in JIS K 6251.

300% Modulus: Tensile Strength at 300% Elongation

Tensile strength: The load at cutting divided by the cross section of the test piece

Modulus represents the tensile strength with respect to elongation, and tensile strength represents the strength with respect to the load of the specimen.

3. Hardness

The measurement was carried out using a type A durometer manufactured by Koubunshi Keiki Co., Ltd. according to the method specified in JIS K 6253.

4. Tear strength

The measurement was carried out at 23 ° C. using a shopper tensile tester in accordance with the method specified in JIS K 6252. The test piece used a crescent type (having a groove). The larger this value means that the crack and chipping caused by accidental defects are less likely to be broken.

5. Permanent extension

Dumbbell-shaped No. 1 was used and the line was 40 mm. In the tensile test of 2, 50% of the elongation at the time of cutting was elongated and maintained in this state for 30 minutes. After 30 minutes had elapsed, the external force was removed, and allowed to stand for 30 minutes to measure the residual elongation at this time. The results expressed the percentage of residual elongation over the circle length (40 mm). The smaller this value is, the less likely it is that deformation due to stress remains. In particular, when the composition is used for tire tread rubber, an improvement (decrease) in rolling resistance is expected.

6. Flexural resistance

According to the method specified in JIS K 6260, the number of flexures during the bending of the length of cracks from 2 mm to 10 mm using a De Mattia flexing tester (Ueshima Seisakusho) Cycle). The thickness of the test piece used was 6.3 mm and the flexural reciprocating motion was 300 times per minute. The movement distance of each test piece holding member was 57 mm, and the maximum distance between the holding members was 75 mm.

In particular, when used as a tire tread rubber, it is preferable that the number of bends is higher. A small number of bends can damage the appearance of the tire surface or cause chipping.

The result obtained about the said evaluation method is shown in Table 1 and Table 2.

Name of sample Example 1 Comparative Example 1 Comparative Example 2 Oilfield SBR [Parts by weight] 100 100 100 Carbon black [Parts by weight] 50 50 50 Modified calcium carbonate [Parts by weight] 10 - 30 Zinc oxide [Parts by weight] 3 3 3 Stearic acid [Parts by weight] 2 2 2 Antioxidant [Parts by weight] One One One Naphthenic oil (containing rubber starch) [Parts by weight] 40.5 40.5 40.5 Vulcanization accelerator 1 [Parts by weight] One One One Vulcanization accelerator 2 [Parts by weight] One One One brimstone [Parts by weight] 2 2 2 [Unvulcanized Rubber Property] Mooney Scorch Time
t5, 125 ℃ 35.2 31.5 32.0 [Vulcanized rubber properties] 300% modulus [MPa] 5.4 5.5 5.2 The tensile strength [MPa] 17.2 15.8 19.2 Hardness 50 50. 49 Phosphorus strength [N / mm] 26.1 24.6 29.8 Permanent extension [%] 4.8 4.5 4.6 Flexural resistance [kC / 2 → 10 mm] 8.0 4.2 8.7

As apparent from the results of Table 1, it was found that the rubber composition of Example 1 has a longer Mooney scotch time than the rubber compositions of Comparative Examples 1 and 2.

In Comparative Example 1, the Mooney scorch time was short, and the tear strength and the flexural resistance were small. In Comparative Example 2, the tear strength and the flexural tear resistance were good, but the improvement in Mooney scotch time was small and the modulus was also slightly decreased.

On the other hand, in Example 1, the Mooney scorch time was long, and favorable results were obtained in various rubber properties such as modulus, tensile strength, flexural resistance.

Name of sample Example 2 Comparative Example 3 Comparative Example 4 Oilfield SBR [Parts by weight] 100 100 100 Silica [Parts by weight] 50 50 50 Modified calcium carbonate [Parts by weight] 5 - 20 Silane coupling agent [Parts by weight] 5 5 5 Zinc oxide [Parts by weight] 3 3 3 Stearic acid [Parts by weight] 2 2 2 Antioxidant [Parts by weight] One One One Naphthenic oil (containing rubber starch) [Parts by weight] 40.5 40.5 40.5 Vulcanization accelerator 1 [Parts by weight] One One One Vulcanization accelerator 2 [Parts by weight] One One One brimstone [Parts by weight] 2 2 2 [Unvulcanized Rubber Property] Mooney Scorch Time
t ₅ , 125 ℃ 44.3 39.8 36.2 [Vulcanized rubber properties] 300% modulus [MPa] 4.3 3.9 4.6 The tensile strength [MPa] 17.8 19.6 17.0 Hardness 56 54 60 Phosphorus strength [N / mm] 33.8 31.5 45.1 Permanent extension [%] 7.6 8.8 7.4 Flexural resistance [kC / 2 → 10 mm] 5.2 4.4 4.9

As apparent from the results of Table 2, it can be seen that the rubber composition of Example 2 has a longer Mooney scotch time than the rubber compositions of Comparative Examples 3 to 4.

The composition of Comparative Example 3 had a short Mooney scorch time and was poor in workability. The rubber composition of Comparative Example 4 had a short Mooney scotch time and a slight decrease in tensile strength.

On the other hand, the composition of this invention of Example 2 has a long Mooney scorch time, and the favorable result was obtained in various physical properties, such as a modulus and a flexion resistance.

The rubber composition of the present invention has an excellent effect on both unvulcanized rubber properties and vulcanized rubber properties by containing a specific amount of the specific components, and is suitable for various fields, for example, industrial materials, OA equipment, automotive, and the like. Available. In particular, the rubber composition of the present invention is excellent in workability and reinforcement, and can be suitably used as a tread rubber composition for tires.

In the present invention, the rubber composition containing carbon black and modified calcium carbonate in combination is particularly excellent in that it can improve the bending resistance heat resistance of the vulcanized rubber without impairing the storage stability of the unvulcanized rubber. Has an effect.

In addition, in the present invention, the composition containing the silica and silane coupling agent and modified calcium carbonate in combination in the rubber composition in particular does not impair the mechanical strength of the rubber composition incorporating only silica and significantly improves the storage stability of the unvulcanized rubber. In particular, it has an excellent effect.

In addition, since the rubber product of the present invention is made of a rubber composition obtained by blending the specific components in a specific ratio, the workability is good, and the rubber product has excellent performance in flexural heat resistance and the like.

Claims (6)

100 parts by weight of at least one rubber selected from natural rubber and synthetic rubber, and the following components 1 and 2: Component 1: 20-100 parts by weight of any one of (1) to (3) selected from the group consisting of (1) carbon black, (2) silica, and (3) a mixture of carbon black and silica, and Component 2: 5 weight part-10 weight part of modified calcium carbonates which have a silica layer and a silane coupling agent layer Consisting of Rubber composition. 100 parts by weight of at least one rubber selected from natural rubber and synthetic rubber, and the following components 1 and 2: Component 1: 20-100 parts by weight of any one of (1) to (3) selected from the group consisting of (1) carbon black, (2) silica, and (3) a mixture of carbon black and silica, and Component 2: (i) Silica layer, (ii) Fatty acid, fatty acid ester, fatty acid ester, resin acid, resin acid salt, and organic acid layer obtained by processing with at least 1 sort (s) chosen from resin acid ester, and (iv) silane 5 parts by weight or more to 10 parts by weight or less of modified calcium carbonate having a coupling agent layer Consisting of Rubber composition. The method according to claim 1 or 2, Component 1 is a mixture of carbon black and silica, wherein the mixing ratio of carbon black to silica is 0.5: 99.5 to 99.5: 0.5 by weight. Rubber composition. The method according to claim 1 or 2, Component 1 is (2) silica, Component 3: Component 3: 0.1-30 weight% of silane coupling agents with respect to the compounding quantity of silica Containing additional Rubber composition. The method according to claim 1 or 2, Component 1 is a mixture of (3) carbon black and silica, Component 3: Component 3: 0.1-30 weight% of a silane coupling agent with respect to the compounding quantity of silica Containing additional Rubber composition. A rubber product obtained by molding the rubber composition according to claim 1.