CN114867591A - Manufacturing method of rubber molded body - Google Patents

Abstract

The present invention provides a method for producing a rubber molded body for producing a rubber molded body by molding an acrylic rubber composition containing a rubber component of acrylic rubber, carbon black, and a crosslinking agent using an extrusion molding machine, wherein the above-mentioned The compounding amount of the carbon black contained in the acrylic rubber composition was set to _CA [phr], the DBP oil absorption value of the carbon black was set to _CD [cc/100g], and the diameter of the screw of the extrusion molding machine was set to When S _D [mm], the screw rotation speed of the extruder is S _S [rpm], and the total number of pitches of the screws of the extruder is S _P , the following formula ( 1) The molding of the above-mentioned acrylic rubber composition using the above-mentioned extrusion molding machine was performed in the form of the following formula (2). 6.5×10 ³ ≤C _A ×C _D ≤1.1×10 ⁴ (1); 3.2×10 ⁶ ≤C _A ×S _D ×S _s ×S _P ≤8.0×10 ⁶ (2).

Description

Manufacturing method of rubber molded body

technical field

The present invention relates to a method for producing a rubber molded body, and more particularly, to a method for producing a rubber molded body capable of producing a rubber molded body having an excellent surface state even after crosslinking with high productivity.

Background technique

Acrylic rubber is a polymer mainly composed of units derived from (meth)acrylate monomers such as alkyl (meth)acrylate monomers and alkoxyalkyl (meth)acrylate monomers. It is widely known as a rubber excellent in heat resistance, oil resistance, and ozone resistance, and it is widely used in automobile-related fields by blending a crosslinking agent to form a rubber crosslinked product.

The rubber cross-linked product of acrylic rubber can be obtained, for example, by extruding an acrylic rubber composition obtained by adding components such as carbon black and a crosslinking agent to a rubber component containing acrylic rubber using an extrusion molding machine to obtain a rubber molded body. , and the obtained rubber molded body is cross-linked (refer to, for example, Patent Document 1). In such a technique of extrusion-molding an acrylic rubber composition, good extrusion processability is required to produce a rubber molded body having an excellent surface state.

However, in the prior art such as the technique described in the above-mentioned Patent Document 1, it is not necessary to manufacture a rubber molded body having an excellent surface state with high productivity, and to manufacture a rubber molded body that can maintain an excellent surface state even after crosslinking. No research.

prior art literature

Patent Literature

Patent Document 1: Japanese Patent Laid-Open No. 2002-220505.

SUMMARY OF THE INVENTION

Invention to solve problem

The present invention has been made in view of such a situation, and an object thereof is to provide a rubber molded body capable of producing a rubber molded body having an excellent surface state even after crosslinking with high productivity.

solution to the problem

The inventors of the present invention have conducted intensive studies in order to achieve the above-mentioned object, and as a result found that the acrylic rubber can be combined by molding an acrylic rubber composition containing a rubber component containing acrylic rubber, carbon black, and a crosslinking agent using an extrusion molding machine. The compounding amount CA of the carbon black contained in the material, the DBP oil absorption value _CD of the carbon black, the diameter _{S D of} the screw of the extrusion molding machine, the screw rotation speed S _S of the extrusion molding machine, and the screw of the extrusion molding machine. The total number of pitches _SP is within a specific range, the obtained rubber molded body can achieve an excellent surface state even after cross-linking, and the rubber molded body can be produced with high productivity, so that the present invention has been completed.

That is, according to the present invention, there can be provided a method for producing a rubber molded body for producing a rubber molding by molding an acrylic rubber composition containing a rubber component containing acrylic rubber, carbon black, and a crosslinking agent using an extrusion molding machine body,

The blending amount of the carbon black contained in the acrylic rubber composition was set to CA [phr], the DBP oil absorption value of the carbon black was set to _{C D [} cc/100g], and the screw of the extruder was set to When the diameter of the extruder is S _D [mm], the screw rotation speed of the extruder is S _S [rpm], and the total screw pitch of the extruder is S _P , the following conditions are satisfied. Molding of the above-mentioned acrylic rubber composition using the above-mentioned extrusion molding machine is carried out in the manner of the above-mentioned formula (1) and the following formula (2),

6.5×10 ³ ≤C _A ×C _D ≤1.1×10 ⁴ (1)

3.2×10 ⁶ ≤C _A ×S _D ×S _S ×SP _≤8.0 ×10 ⁶ (2).

In the manufacturing method of the rubber molded article of the present invention, it is preferable that the acrylic rubber contains a (meth)acrylate monomer unit and a crosslinkable monomer unit, and the (meth)acrylic acid among the monomer units constituting the acrylic rubber is preferably The content of the ester monomer unit is 50% by weight or more, and the content of the above-mentioned crosslinkable monomer unit is 0.1% by weight or more.

In the manufacturing method of the rubber molded object of this invention, it is preferable that the said crosslinkable monomer unit is a unit of an α,β-ethylenically unsaturated carboxylic acid monomer.

In the manufacturing method of the rubber molded object of this invention, it is preferable that the said crosslinkable monomer unit is a unit of an α,β-ethylenically unsaturated dicarboxylic acid monoester monomer.

In the manufacturing method of the rubber molded object of this invention, it is preferable that the compounding quantity CA of the said carbon black is _40-120 phr.

In the manufacturing method of the rubber molded object of this invention, it is preferable that the said extrusion molding machine is a uniaxial extrusion molding machine.

Further, according to the present invention, there can be provided a method for producing a cross-linked rubber, which includes a step of obtaining a rubber molded body and a step of crosslinking the above-described rubber molded body according to any of the above-described production methods.

Invention effect

According to the present invention, it is possible to provide a rubber molded body capable of producing a rubber molded body having an excellent surface state even after crosslinking with high productivity.

Description of drawings

FIG. 1 is a schematic view showing an extrusion molding machine used in a method for producing a rubber molded body according to an embodiment of the present invention.

FIG. 2 is a schematic view showing a screw arranged inside the extrusion molding machine.

Detailed ways

The method for producing a rubber molded body of the present invention is a method for producing a rubber molded body by molding an acrylic rubber composition containing a rubber component of acrylic rubber, carbon black, and a crosslinking agent using an extrusion molding machine,

The blending amount of the carbon black contained in the acrylic rubber composition was set to CA [phr], the DBP oil absorption value of the carbon black was set to _{C D [} cc/100g], and the screw of the extruder was set to When the diameter of the extruder is S _D [mm], the screw rotation speed of the extruder is S _S [rpm], and the total screw pitch of the extruder is S _P , the following conditions are satisfied. Molding of the above-mentioned acrylic rubber composition using the above-mentioned extrusion molding machine is carried out in the manner of the above-mentioned formula (1) and the following formula (2),

6.5×10 ³ ≤C _A ×C _D ≤1.1×10 ⁴ (1)

3.2×10 ⁶ ≤C _A ×S _D ×S _S ×SP _≤8.0 ×10 ⁶ (2).

<Acrylic rubber>

First, the acrylic rubber used in the production method of the present invention will be described.

The acrylic rubber used in the present invention is a (meth)acrylate monomer (meth)acrylate monomer (meth)acrylate containing in the molecule as a main component (meaning that there is preferably 50% by weight or more of monomeric units in all monomeric units constituting the acrylic rubber). Meaning of monomer and/or methacrylate monomer. Hereinafter, the same applies to methyl (meth)acrylate and the like. ] units of rubbery polymers.

It does not specifically limit as a (meth)acrylate monomer which forms a (meth)acrylate monomer unit which is a main component of the acrylic rubber used in the present invention, For example, an alkyl (meth)acrylate monomer can be mentioned. And (meth)acrylic acid alkoxyalkyl ester monomer and so on.

The alkyl (meth)acrylate monomer is not particularly limited, but is preferably an ester of an alkanol having 1 to 12 carbon atoms and (meth)acrylic acid ((methyl) having an alkyl group having 1 to 12 carbon atoms (meth)acrylate), esters of alkanols having 1 to 8 carbon atoms and (meth)acrylic acid ((meth)acrylates having an alkyl group having 1 to 8 carbon atoms) are more preferred, and carbon atoms are still more preferred. Esters of alkanols having 2 to 6 atoms and (meth)acrylic acid ((meth)acrylates having an alkyl group having 2 to 6 carbon atoms).

Specific examples of alkyl (meth)acrylate monomers include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, and isopropyl (meth)acrylate. ester, n-butyl (meth)acrylate, isobutyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and cyclohexyl (meth)acrylate Wait. Among these, ethyl (meth)acrylate and n-butyl (meth)acrylate are preferred, and ethyl acrylate and n-butyl acrylate are more preferred. These can be used individually by 1 type or in combination of 2 or more types.

The (meth)acrylic acid alkoxyalkyl ester monomer is not particularly limited, but is preferably an alkoxyalkyl alcohol having 2 to 12 carbon atoms and an ester of (meth)acrylic acid (having 2 to 12 carbon atoms) (meth)acrylate of alkoxyalkyl group of 12), more preferably ester of alkoxyalkyl alcohol with 2 to 8 carbon atoms and (meth)acrylic acid (with 2 to 8 carbon atoms) (meth)acrylate of an alkoxyalkyl group), more preferably an ester of an alkoxyalkyl alcohol having 2 to 6 carbon atoms and (meth)acrylic acid (having an alkoxy group having 2 to 6 carbon atoms) (meth)acrylates of alkyl groups).

Specific examples of alkoxyalkyl (meth)acrylate include methoxymethyl (meth)acrylate, ethoxymethyl (meth)acrylate, and 2-methyl (meth)acrylate. 2-ethoxyethyl (meth)acrylate, 2-propoxyethyl (meth)acrylate, 2-butoxyethyl (meth)acrylate, (meth)acrylate ) acrylic acid-3-methoxypropyl ester and (meth)acrylic acid-4-methoxybutyl ester, etc. Among these, 2-ethoxyethyl (meth)acrylate and 2-methoxyethyl (meth)acrylate are preferred, and 2-ethoxyethyl acrylate and 2-methoxyethyl acrylate are particularly preferred. Methoxyethyl ester. These can be used individually by 1 type or in combination of 2 or more types.

In the acrylic rubber used in the present invention, it is preferable to use 30 to 100% by weight of alkyl (meth)acrylate monomer units and 70 to 0% by weight of alkoxyalkyl (meth)acrylate monomers The monomer unit formed by the unit is referred to as a (meth)acrylate monomer unit.

The content of the (meth)acrylate monomer units in the monomer units constituting the acrylic rubber used in the present invention is preferably 50% by weight or more, more preferably 60% by weight or more, still more preferably 70 to 99.9% by weight, and even more preferably 70 to 99.9% by weight. More preferably, it is 80 to 99.5% by weight, and particularly preferably 90 to 99% by weight. When the content of the (meth)acrylate monomer unit is too small, the weather resistance, heat resistance, and oil resistance of the obtained rubber cross-linked product may decrease.

The acrylic rubber used in the present invention may contain, if necessary, a crosslinkable monomer unit in addition to the (meth)acrylate monomer unit. It does not specifically limit as a crosslinkable monomer which forms a crosslinkable monomer unit, For example, an α,β-ethylenically unsaturated carboxylic acid monomer, a monomer having an epoxy group, and a monomer having a halogen atom are mentioned. , diene monomers, etc. As the crosslinkable monomer, α,β-ethylenically unsaturated carboxylic acid is preferable from the viewpoint of further improving the scorching stability of the rubber composition of acrylic rubber, the heat resistance of the rubber cross-linked product, and the compression set. Monomers, monomers having epoxy groups, monomers having halogen atoms, more preferably α,β-ethylenically unsaturated carboxylic acid monomers, monomers having epoxy groups, particularly preferably α,β-ethylenically unsaturated carboxylic acid monomers Saturated carboxylic acid monomer.

It does not specifically limit as an α,β-ethylenically unsaturated carboxylic acid monomer, For example, α,β-ethylenically unsaturated monocarboxylic acid, α,β-ethylenically unsaturated dicarboxylic acid, and α,β- Olefinically unsaturated dicarboxylic acid monoesters, etc. By using an α,β-ethylenically unsaturated carboxylic acid monomer, the acrylic rubber can be made into a carboxyl group-containing acrylic rubber having a carboxyl group as a crosslinking point, thereby making it possible to further improve the permanent compression resistance in the case of a rubber crosslinked product deformability.

The α,β-ethylenically unsaturated monocarboxylic acid is not particularly limited, but is preferably an α,β-ethylenically unsaturated monocarboxylic acid having 3 to 12 carbon atoms, and specific examples thereof include acrylic acid, methyl Acrylic acid, α-ethacrylic acid, crotonic acid and cinnamic acid, etc.

The α,β-ethylenically unsaturated dicarboxylic acid is not particularly limited, but is preferably an α,β-ethylenically unsaturated dicarboxylic acid having 4 to 12 carbon atoms, and specific examples thereof include fumaric acid. , butenedioic acid such as maleic acid; itaconic acid; citraconic acid; chloromaleic acid, etc.

The α,β-ethylenically unsaturated dicarboxylic acid monoester is not particularly limited, but is preferably an α,β-ethylenically unsaturated dicarboxylic acid having 4 to 12 carbon atoms and an alkanol having 1 to 12 carbon atoms. Monoesters of α, β-ethylenically unsaturated dicarboxylic acids with 4 to 6 carbon atoms and alkanols with 2 to 8 carbon atoms are more preferable, butene with 4 carbon atoms is more preferable Monoester of a diacid and an alkanol having 2 to 6 carbon atoms. Specific examples of α,β-ethylenically unsaturated dicarboxylic acid monoester include monomethyl fumarate, monoethyl fumarate, mono-n-butyl fumarate, and monomethyl maleate , monoethyl maleate, mono-n-butyl maleate and other butenedioic acid monochain alkyl esters; monocyclopentyl fumarate, monocyclohexyl fumarate, monocyclohexene fumarate ester, monocyclopentyl maleate, monocyclohexyl maleate, monocyclohexenyl maleate and other butenedioic acid monoesters with alicyclic structure; Itaconic acid monoesters such as ethyl ester, itaconic acid mono-n-butyl ester, itaconic acid monocyclohexyl ester, etc.

Among these, α,β-ethylenically unsaturated dicarboxylic acid monoester is preferable, butenedioic acid monochain alkyl ester or butenedioic acid monoester having an alicyclic structure is more preferable, and fumaric acid is further preferable Mono-n-butyl ester, mono-n-butyl maleate, mono-cyclohexyl fumarate and mono-cyclohexyl maleate, particularly preferably mono-n-butyl fumarate. These α,β-ethylenically unsaturated carboxylic acid monomers can be used alone or in combination of two or more. In addition, among the above-mentioned monomers, the dicarboxylic acid also includes a monomer that exists as an acid anhydride.

Although it does not specifically limit as a monomer which has an epoxy group, For example, (meth)acrylate containing an epoxy group, such as glycidyl (meth)acrylate; Allyl glycidyl ether and vinyl glycidyl Ethers and the like include epoxy group-containing ethers and the like.

The monomer having a halogen atom is not particularly limited, and examples thereof include unsaturated alcohol esters of halogen-containing saturated carboxylic acids, haloalkyl (meth)acrylates, haloacyloxyalkyl (meth)acrylates, (Meth)acrylic acid (haloacetylcarbamoyloxy)alkyl esters, halogenated unsaturated ethers, halogenated unsaturated ketones, halogenated methyl-containing aromatic vinyl compounds, halogenated unsaturated amides and Halogenated acetyl-containing unsaturated monomers, etc. Moreover, as a monomer which has a halogen atom, the monomer which contains a chlorine atom as a halogen atom is preferable.

Specific examples of the unsaturated alcohol ester of the halogen-containing saturated carboxylic acid include vinyl chloroacetate, vinyl 2-chloropropionate, and allyl chloroacetate.

Specific examples of (meth)acrylate haloalkyl esters include chloromethyl (meth)acrylate, 1-chloroethyl (meth)acrylate, 2-chloroethyl (meth)acrylate, (meth)acrylate 1,2-dichloroethyl meth)acrylate, 2-chloropropyl (meth)acrylate, 3-chloropropyl (meth)acrylate and 2,3-dichloro (meth)acrylate Propyl ester etc.

Specific examples of (meth)acrylic acid haloacyloxyalkyl esters include (meth)acrylic acid-2-(chloroacetoxy)ethyl, (meth)acrylic acid-2-(chloroacetoxy) (meth)acrylic acid-3-(chloroacetoxy)propyl ester and (meth)acrylic acid-3-(hydroxychloroacetoxy)propyl ester and the like.

Specific examples of (haloacetylcarbamoyloxy)alkyl (meth)acrylate include 2-(chloroacetylcarbamoyloxy)ethyl (meth)acrylate and (meth)acrylate base) acrylate-3-(chloroacetylcarbamoyloxy)propyl ester and the like.

Specific examples of halogen-containing unsaturated ethers include chloromethyl vinyl ether, 2-chloroethyl vinyl ether, 3-chloropropyl vinyl ether, 2-chloroethyl allyl ether, and 3-chloroethyl vinyl ether. Chloropropyl allyl ether, etc.

Specific examples of the halogen-containing unsaturated ketone include 2-chloroethyl vinyl ketone, 3-chloropropyl vinyl ketone, and 2-chloroethyl allyl ketone.

Specific examples of the halogenated methyl group-containing aromatic vinyl compound include p-chloromethylstyrene, m-chloromethylstyrene, o-chloromethylstyrene, and p-chloromethyl-α-methylbenzene Ethylene etc.

Specific examples of the halogen-containing unsaturated amide include N-chloromethyl(meth)acrylamide and the like.

Specific examples of the halogenated acetyl group-containing unsaturated monomer include 3-(hydroxychloroacetoxy)propyl allyl ether, p-vinylbenzyl chloroacetate, and the like.

Examples of diene monomers include conjugated diene monomers such as 1,3-butadiene, isoprene, and piperylene; Conjugated diene monomers; (meth)acrylic acid dicyclopentadienyl ester, (meth)acrylic acid-2-dicyclopentadienyl ethyl ester, etc. (meth)acrylic acid and enol ester, etc.

The content of the crosslinkable monomer unit in the monomer unit constituting the acrylic rubber used in the present invention is preferably 0.01% by weight or more, more preferably 0.01 to 20% by weight, still more preferably 0.1 to 10% by weight, still more preferably It is 0.5 to 5% by weight, particularly preferably 1 to 3% by weight. By making the content of the crosslinkable monomer unit within the above-mentioned range, the mechanical properties and heat resistance of the obtained cross-linked rubber can be improved, and the compression set resistance can be improved more appropriately.

In addition, the acrylic rubber used in the present invention may have a (meth)acrylate monomer unit and a crosslinkable monomer unit used as needed, and may have a unit of another monomer copolymerizable with these. It does not specifically limit as such another monomer which can be copolymerized, An aromatic vinyl monomer, an α,β-ethylenically unsaturated nitrile monomer, an acrylamide-based monomer, an α,β-ethylenically unsaturated monomer can be mentioned. Dicarboxylic acid diester monomers, other olefin-based monomers, and the like.

As an aromatic vinyl monomer, styrene, (alpha)-methylstyrene, divinylbenzene, etc. are mentioned.

As an α,β-ethylenically unsaturated nitrile monomer, acrylonitrile, methacrylonitrile, etc. are mentioned.

As acrylamide type monomers, acrylamide, methacrylamide, etc. are mentioned.

Examples of the α,β-ethylenically unsaturated dicarboxylic acid diester monomer include maleic acid having an alkyl group of 1 to 18 carbon atoms, such as dimethyl maleate and di-n-butyl maleate. Dialkyl esters; dialkyl fumarate with alkyl groups such as dimethyl fumarate and di-n-butyl fumarate having 1 to 18 carbon atoms; dicyclopentyl maleate, maleic acid Dicycloalkyl maleate with a cycloalkyl group such as dicyclohexyl having 4 to 16 carbon atoms; and a cycloalkyl group such as dicyclopentyl fumarate and dicyclohexyl fumarate with a carbon number of Dicycloalkyl fumarate of 4 to 16; dialkyl itaconic acid of which the alkyl group such as dimethyl itaconic acid and di-n-butyl itaconic acid has an alkyl group of 1 to 18; itaconic acid Dicycloalkyl esters of itaconic acid having 4 to 16 carbon atoms in the cycloalkyl group such as dicyclohexyl ester and the like.

Examples of other olefin-based monomers include ethylene, propylene, vinyl chloride, vinylidene chloride, vinyl acetate, ethyl vinyl ether, butyl vinyl ether, and the like.

Other monomers which can be copolymerized can be used alone or in combination of two or more. The content of the units of these other copolymerizable monomers in the monomer units constituting the acrylic rubber used in the present invention is preferably 49.9% by weight or less, more preferably 29.9% by weight or less, still more preferably 15% by weight or less, and still more It is preferably 9% by weight or less, particularly preferably 4.5% by weight or less.

Moreover, the Mooney viscosity (ML1+4, 100 degreeC) of the acrylic rubber used in this invention is the range of 10-150, Preferably it is the range of 20-100, More preferably, it is the range of 25-70. By making the Mooney viscosity within the above range, the processability and strength characteristics of the acrylic rubber can be highly balanced.

The glass transition temperature (Tg) of the acrylic rubber used in the present invention is not particularly limited, but is preferably 0°C or lower, more preferably -5°C or lower, and further preferably -10°C or lower. In addition, the lower limit of the glass transition temperature (Tg) is not particularly limited, but it is preferably -80°C or higher, more preferably -60°C or higher, and further preferably -40°C or higher. By making the glass transition temperature (Tg) in the above-mentioned range, the balance of heat resistance and cold resistance of the acrylic rubber can be further improved.

The acrylic rubber used in the present invention can be produced by copolymerizing (radical polymerization) the above-mentioned monomers by a known method such as emulsion polymerization, suspension polymerization, solution polymerization, and bulk polymerization. Among these polymerization methods, emulsion polymerization is preferable, and in the case of emulsion polymerization, polymerization is preferably carried out at low temperature (100° C. or lower) and normal pressure from the viewpoint of easy production of acrylic rubber. In addition to the emulsifier and the polymerization initiator, commonly used polymerization auxiliary materials can be used in the emulsion polymerization.

The emulsifier is not particularly limited, and examples thereof include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene alkyl phenol ethers such as polyoxyethylene nonylphenyl ether, and polyoxyethylene rigid Nonionic emulsifiers such as polyoxyethylene alkyl esters such as fatty acid esters, polyoxyethylene sorbitan alkyl esters, and polyoxyethylene polyoxypropylene copolymers; myristic acid, palmitic acid, oleic acid, linolenic acid, etc. Salts of fatty acids, alkylbenzenesulfonates such as sodium dodecylbenzenesulfonate, higher alcohol sulfates such as sodium lauryl sulfate, higher phosphates such as sodium alkylphosphate, alkylsulfosuccinates, etc. Anionic emulsifiers; cationic emulsifiers such as alkyl trimethyl ammonium chloride, dialkyl ammonium chloride, benzyl ammonium chloride, etc. The amount of the emulsifier used is preferably 0.1 to 10 parts by weight, and more preferably 0.5 to 5 parts by weight with respect to 100 parts by weight of the monomer used for polymerization.

The polymerization initiator is not particularly limited and can be used: azo compounds such as azobisisobutyronitrile; dicumene hydroperoxide, cumene hydroperoxide, p-terpane hydroperoxide, benzoyl peroxide, etc. Organic peroxides; inorganic peroxides such as sodium persulfate, potassium persulfate, hydrogen peroxide, ammonium persulfate, etc. These polymerization initiators can be used alone or in combination of two or more. It is preferable that the usage-amount of a polymerization initiator is 0.001-1.0 weight part with respect to 100 weight part of monomers used for polymerization.

In addition, the organic peroxide and the inorganic peroxide as the polymerization initiator are preferably used in combination with a reducing agent as a redox-based polymerization initiator. The reducing agent used in combination is not particularly limited, and examples thereof include compounds containing metal ions in a reduced state, such as ferrous sulfate, sodium ferric hexamethylenediaminetetraacetate, and cuprous naphthenate; ascorbic acid, sodium ascorbate, Ascorbic acid (salt) such as potassium ascorbate; erythorbic acid (salt) such as erythorbic acid, sodium erythorbate, potassium erythorbate; sugars; sulfinate such as sodium hydroxymethanesulfinate; sodium sulfite, potassium sulfite, sodium bisulfite , Sulfites such as aldehyde sodium bisulfite, potassium bisulfite; sodium metabisulfite, potassium metabisulfite, sodium metabisulfite, potassium metabisulfite and other metabisulfites; sodium thiosulfate, potassium thiosulfate isothiosulfate; phosphorous acid (salt) such as phosphorous acid, sodium phosphite, potassium phosphite, sodium hydrogen phosphite, potassium hydrogen phosphite; pyrophosphite, sodium pyrophosphite, potassium pyrophosphite, pyrophosphite Sodium hydrogen, potassium hydrogen pyrophosphite and other pyrophosphites (salts); sodium formaldehyde sulfoxylate, etc. These reducing agents can be used alone or in combination of two or more. It is preferable that the usage-amount of a reducing agent is 0.0003-0.1 weight part with respect to 100 weight part of polymerization initiators.

In addition, in the production of acrylic rubber, in addition to emulsifiers and polymerization initiators, polymerization auxiliary materials such as molecular weight regulators, particle size regulators, chelating agents, and oxygen scavengers that are generally used in the production of acrylic rubbers can also be used. Auxiliary materials such as polymerization.

<Acrylic rubber composition>

Next, the acrylic rubber composition used in the production method of the present invention will be described.

The acrylic rubber composition used in the production method of the present invention contains a rubber component containing acrylic rubber, carbon black, and a crosslinking agent.

The content ratio of the acrylic rubber in the rubber component may be appropriately selected according to the purpose of use, and is preferably 30% by weight or more, more preferably 50% by weight or more, still more preferably 70% by weight or more, still more preferably 90% by weight or more, particularly It is preferably 100% by weight (that is, a method of using substantially only rubber consisting of acrylic rubber as the rubber component.)

The rubber other than the acrylic rubber constituting the rubber component is not particularly limited, and examples thereof include natural rubber, polybutadiene rubber, polyisoprene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, Silicone rubber, fluororubber, olefin-based elastomers, styrene-based elastomers, vinyl chloride-based elastomers, polyester-based elastomers, polyamide-based elastomers, polyurethane-based elastomers, polysiloxane-based elastomers, and the like.

Although it does not specifically limit as carbon black, Furnace black, acetylene black, thermal black, channel black, graphite etc. are mentioned. Among these, furnace carbon black is preferably used, and specific examples thereof include SAF, ISAF, ISAF-HS, ISAF-LS, IISAF-HS, HAF, HAF-HS, HAF-LS, MAF, FEF, etc. . These can be used individually or in combination of 2 or more types, respectively.

In addition, in the present invention, when the compounding amount of the carbon black blended in the acrylic rubber composition is set to _CA [phr] and the DBP oil absorption value of the carbon black is set to _CD [cc/100g], these The condition of the following formula (1) is satisfied.

6.5×10 ³ ≤C _A ×C _D ≤1.1×10 ⁴ (1)

According to the present invention, the compounding amount _CA of carbon black and the DBP oil absorption value _CD of carbon black satisfy the above-mentioned formula (1), and as will be described later, the acrylic rubber composition is used in an extrusion molding machine to produce rubber molding The compounding amount of carbon black CA in the body, the diameter _{S D of} the screw of the extrusion molding machine, the rotational speed of the screw of the extrusion molding machine _{S S} , and the total pitch number SP of the screw of the extrusion molding machine satisfy the following formula ( 2), whereby a rubber molded body capable of achieving an excellent surface state even after crosslinking can be produced with high productivity.

The blending amount _CA of carbon black and the DBP oil absorption value _CD of carbon black may satisfy the above formula (1), preferably the following formula (3), and more preferably the following formula (4). If the value of “C _A ×C _D ” is too small, the surface state of the obtained rubber molded body and rubber cross-linked product will deteriorate, and if the value of “C _A × _CD ” is too large, the productivity of the acrylic rubber molded body will deteriorate. will decline.

6.5×10 ³ ≤C _A ×C _D ≤1.0×10 ⁴ (3)

6.5×10 ³ ≤C _A ×C _D ≤9.0×10 ³ (4)

The compounding amount of carbon black, C _A [phr; per hundred rubber], is the compounding amount (unit is "parts by weight") of the rubber component containing the acrylic rubber contained in the acrylic rubber composition in an amount of 100 parts by weight (unit: "parts by weight") so as to be combined with the carbon black. _The relational meter of the _DBP oil absorption value CD of black may satisfy the above-mentioned formula (1).

In addition, the DBP oil absorption value C _D [cc/100g] of carbon black is the amount (unit is "cc") of DBP (dibutyl phthalate) absorbed by 100 g of carbon black, and is measured based on JIS K6221. As long as the carbon black DBP oil absorption value C _D satisfies the above formula (1) in terms of the relationship with the carbon black compounding amount C _A ~160cc/100g, particularly preferably 95~140cc/100g.

盐；咪唑化合物；异氰脲酸化合物等现有公知的交联剂。这些交联剂能够单独使用一种或组合使用两种以上。作为交联剂，优选根据交联性单体单元的种类进行适当选择。The crosslinking agent is not particularly limited, and for example, polyamine compounds such as diamine compounds and carbonates thereof; sulfur; sulfur donors; triazine thiol compounds; polyvalent epoxy compounds; organic carboxylic acid ammonium salts; organic peroxides oxide; metal dithiocarbamate; polycarboxylic acid; quaternary

salts; imidazole compounds; isocyanuric acid compounds and other conventionally known crosslinking agents. These crosslinking agents can be used alone or in combination of two or more. As a crosslinking agent, it is preferable to select suitably according to the kind of crosslinkable monomer unit.

Among these, when the acrylic rubber used in the present invention has an α,β-ethylenically unsaturated carboxylic acid monomer unit as a crosslinkable monomer unit, as the crosslinking agent, polyamine compounds and its carbonate.

Although it does not specifically limit as a polyamine compound and its carbonate, C4-C30 polyamine compound and its carbonate are preferable. As an example of such a polyamine compound and its carbonate, an aliphatic polyamine compound and its carbonate, an aromatic polyamine compound, etc. are mentioned.

It does not specifically limit as an aliphatic polyamine compound and its carbonate, For example, hexamethylene diamine, hexamethylene diamine carbamate, and N,N'-dicinnamylidene-1, 6 hexanediamine, etc. Among these, hexamethylenediamine carbamate is preferable.

It does not specifically limit as an aromatic polyamine compound, For example, 4, 4'- methylene diphenylamine, p-phenylenediamine, m-phenylenediamine, 4, 4'- diamino diphenyl ether, 3, 4'-Diaminodiphenyl ether, 4,4'-(m-phenylenediisopropylidene)diphenylamine, 4,4'-(p-phenylenediisopropylidene)diphenylamine, 2 ,2'-bis[4-(4-aminophenoxy)phenyl]propane, 4,4'-diaminobenzanilide, 4,4'-bis(4-aminophenoxy)biphenyl, m-xylylenediamine, p-xylylenediamine and 1,3,5-benzenetriamine, etc. Among these, 2,2'-bis[4-(4-aminophenoxy)phenyl]propane is preferred.

The content of the crosslinking agent in the acrylic rubber composition used in the present invention is preferably 0.001 to 20 parts by weight, more preferably 0.1 to 10 parts by weight, and still more preferably 0.1 parts by weight relative to 100 parts by weight of the rubber component containing the acrylic rubber. to 5 parts by weight, particularly preferably 0.2 to 4 parts by weight. By making the content of the crosslinking agent in the above-mentioned range, sufficient rubber elasticity can be obtained, and the resulting crosslinked rubber can be made excellent in mechanical strength.

盐、叔膦化合物、脂肪族一元仲胺化合物及脂肪族一元叔胺化合物等。在这些之中，优选胍化合物、二氮杂双环烯烃化合物及脂肪族一元仲胺化合物，特别优选胍化合物和二氮杂双环烯烃化合物。这些碱性交联促进剂能够单独使用一种或组合使用两种以上。In addition, the acrylic rubber composition preferably further contains a crosslinking accelerator. The crosslinking accelerator is not particularly limited, and when the acrylic rubber has a carboxyl group as a crosslinkable group and the crosslinking agent is a polyamine compound or a carbonate thereof, a guanidine compound, a diazabicycloolefin can be used compound, imidazole compound, quaternary

Salts, tertiary phosphine compounds, aliphatic monobasic secondary amine compounds and aliphatic monobasic tertiary amine compounds, etc. Among these, guanidine compounds, diazabicycloolefin compounds, and aliphatic monovalent secondary amine compounds are preferable, and guanidine compounds and diazabicycloolefin compounds are particularly preferable. These alkaline crosslinking accelerators can be used alone or in combination of two or more.

盐的具体例子，可举出四正丁基溴化铵、十八烷基三正丁基溴化铵等。作为叔膦化合物的具体例子，可举出三苯基膦、三对甲苯基膦等。Specific examples of the guanidine compound include 1,3-bis-o-tolylguanidine, 1,3-diphenylguanidine, and the like. Specific examples of the diazabicycloolefin compound include 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,5-diazabicyclo[4.3.0]nonan-5 -ene, etc. Specific examples of the imidazole compound include 2-methylimidazole, 2-phenylimidazole, and the like. as a season

Specific examples of the salt include tetra-n-butylammonium bromide, octadecyltri-n-butylammonium bromide, and the like. Specific examples of the tertiary phosphine compound include triphenylphosphine, tri-p-tolylphosphine, and the like.

The aliphatic monovalent secondary amine compound is a compound in which two hydrogen atoms of ammonia are replaced by aliphatic hydrocarbon groups. The aliphatic hydrocarbon group substituted for a hydrogen atom is preferably an aliphatic hydrocarbon group having 1 to 30 carbon atoms. Specific examples of aliphatic monovalent secondary amine compounds include dimethylamine, diethylamine, dipropylamine, diallylamine, diisopropylamine, di-n-butylamine, di-tert-butylamine, Di-sec-butylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, bis(undecyl)amine, bis(dodecyl)amine, bis(dodecyl)amine Tridecyl)amine, di(tetradecyl)amine, di(pentadecyl)amine, di(hexadecyl)amine, di-2-ethylhexylamine and di(octadecyl)amine Amines etc.

Aliphatic monovalent tertiary amine compounds are compounds in which all three hydrogen atoms of ammonia are substituted by aliphatic hydrocarbon groups. The aliphatic hydrocarbon group substituted for a hydrogen atom is preferably an aliphatic hydrocarbon group having 1 to 30 carbon atoms. Specific examples of the aliphatic monovalent tertiary amine compound include trimethylamine, triethylamine, tripropylamine, triallylamine, triisopropylamine, tri-n-butylamine, tri-tert-butylamine, tri-secondary amine Butylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, tri(undecyl)amine, tris(dodecyl)amine, and the like.

The content of the crosslinking accelerator in the acrylic rubber composition is preferably 0.1 to 10 parts by weight, more preferably 0.5 to 7.5 parts by weight, and still more preferably 1 to 5 parts by weight relative to 100 parts by weight of the rubber component containing the acrylic rubber . By setting the content of the crosslinking accelerator in the above range, the tensile strength and compression set resistance of the obtained cross-linked rubber can be further improved.

In addition, the acrylic rubber composition may contain an anti-aging agent as needed. It does not specifically limit as an antioxidant, Phenyl-α-naphthylamine, phenyl-β-naphthylamine, p-(p-toluenesulfonamide)-diphenylamine, 4,4'-bis(α,α) - Dimethylbenzyl) diphenylamine, N,N-diphenyl-p-phenylenediamine, N-isopropyl-N'-phenyl-p-phenylenediamine, butyraldehyde-aniline condensate and other amine-based antioxidants ; 2-mercaptobenzimidazole and other imidazole-based antioxidants; 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline and other quinoline-based antioxidants, etc. Among these, amine-based antioxidants are preferred.

An antioxidant can be used individually by 1 type or in combination of 2 or more types. The content of the antioxidant in the acrylic rubber composition is not particularly limited, but is preferably 0.01 to 15 parts by weight, more preferably 0.05 to 10 parts by weight, and even more preferably 0.1 to 100 parts by weight of the rubber component containing the acrylic rubber. 5 parts by weight.

Moreover, the acrylic rubber composition used in the manufacturing method of this invention can mix|blend the compounding agent which can be used normally in the field of rubber processing in addition to the said each component. Examples of such compounding agents include: reinforcing fillers such as silica; non-reinforcing fillers such as calcium carbonate and clay; light stabilizers; anti-scorch agents; plasticizers; processing aids; Mixtures; Lubricants; Lubricants; Flame Retardants; Antifungal Agents; Antistatic Agents; Colorants, etc. The compounding quantity of these compounding agents is not specifically limited in the range which does not impair the objective and effect of this invention, The quantity according to the compounding objective can be suitably compounded.

The acrylic rubber composition of the present invention is prepared by compounding carbon black, a crosslinking agent, and other various compounding agents as necessary to the above-mentioned rubber component containing acrylic rubber, and kneading with an open roll mill or Banbury. It is prepared by mixing and kneading using a kneader, various kneaders, etc., and then further kneading using a kneading roll.

The mixing order of each component is not particularly limited, but after sufficiently mixing the components that are difficult to react and decompose by heat, it is preferable to mix the crosslinking agent, etc., which are easily reacted and decomposed by heat, in a short period of time at a temperature at which no reaction or decomposition occurs. mix.

<Manufacturing method of rubber molded body>

The method for producing a rubber molded body of the present invention is for producing a rubber molded body by molding an acrylic rubber composition containing a rubber component containing acrylic rubber, carbon black, and a crosslinking agent using an extrusion molding machine,

The blending amount of the carbon black contained in the acrylic rubber composition was set to CA [phr], the DBP oil absorption value of the carbon black was set to _{C D [} cc/100g], and the screw of the extruder was set to When the diameter of the extruder is S _D [mm], the screw rotation speed of the extruder is S _S [rpm], and the total screw pitch of the extruder is S _P , the following conditions are satisfied. Molding of the above-mentioned acrylic rubber composition using the above-mentioned extrusion molding machine was performed in the form of the above-mentioned formula (1) and the following formula (2).

6.5×10 ³ ≤C _A ×C _D ≤1.1×10 ⁴ (1)

3.2×10 ⁶ ≤C _A ×S _D ×S _S ×S _P ≤8.0×10 ⁶ (2)

FIG. 1 is a schematic view showing an extrusion molding machine used in a method for producing a rubber molded body according to an embodiment of the present invention. Hereinafter, as the extrusion molding machine used in the manufacturing method of the rubber molding of the present invention, the case where the extrusion molding machine of one embodiment shown in FIG. 1 is used is exemplified, and the acrylic rubber composition is extruded to obtain a rubber. The method of forming a body is demonstrated.

As shown in FIG. 1, the extrusion molding machine 1 which concerns on one Embodiment has the drive unit 2 and the single cylinder 3 which consists of 11 divided cylinder blocks 31-41. In addition, the screw 6 shown in FIG. 2 is arranged inside the barrel 3, and among the barrel blocks constituting the barrel 3, a device for connecting the inside of the barrel 3 is connected to the downstream side of the barrel block 41 located on the most downstream side. The kneaded acrylic rubber composition is molded into a die 5 having a predetermined shape, and a rubber molded body having a predetermined shape can be extruded. The die 5 may have a cutter for cutting the extruded rubber molded body into a predetermined size. In addition, in FIG. 1 , as the barrel 3, a structure composed of 11 barrel blocks 31 to 41 is exemplified, but the number of barrel blocks is not particularly limited, and may be more than that shown in FIG. 1 or may be There are few ways shown in FIG. 1 .

FIG. 2 is a schematic diagram showing a screw arranged inside the extrusion molding machine 1 . A screw 6 as shown in FIG. 2 is arranged inside the barrel 3 . That is, the extrusion molding machine 1 is a uniaxial extrusion molding machine. A drive unit such as a motor housed in the drive unit 2 (refer to FIG. 1 ) is connected to the bottom end of the screw 6 to drive the screw 6 , thereby holding the screw 6 rotatably. The shape of the screw 6 is not particularly limited, and examples thereof include a full-flight type bidirectional screw and the like.

In the method for producing a rubber molded body of the present invention, the acrylic rubber composition is charged into the extrusion molding machine 1 as described above, and the charged acrylic rubber composition is generated by the rotation of the screw 6 in the barrel 3 while the acrylic rubber composition is charged. It can be extruded into a rubber molded body having a predetermined shape through the die 5 while being conveyed to the downstream side while being kneaded by shearing force.

Then, in the method for producing a rubber molded body of the present invention, when performing extrusion molding using such an extrusion molding machine 1, the diameter of the screw 6 of the extrusion molding machine 1 is set to S _D [mm], When the rotational speed of the screw 6 of the extruder 1 is S _S [rpm] and the total number of pitches of the screw 6 of the extruder 1 is S _P , these are included in the acrylic rubber composition. The relation of the compounding amount _CA [phr] of the carbon black satisfies the following formula (2).

3.2×10 ⁶ ≤C _A ×S _D ×S _S ×S _P ≤8.0×10 ⁶ (2)

In the present invention, as described above, the compounding amount _CA of carbon black and the DBP oil absorption value _CD of carbon black satisfy the above-mentioned formula (1), and the extruder 1 uses the acrylic rubber composition to produce a rubber The compounding amount CA of carbon black in the molding, the diameter S _D of the screw ₆ of the extrusion molding machine 1, the rotational speed S _S of the screw 6 of the extrusion molding machine 1, and the total pitch of the screw 6 of the extrusion molding machine 1 When the number S _P satisfies the above formula (2), a rubber molded body capable of realizing an excellent surface state even after crosslinking can be produced with high productivity.

The compounding amount C _A of carbon black, the diameter S _D of the screw 6 of the extruder 1 , the rotational speed _{S S} of the screw 6 of the extruder 1 , and the total pitch number SP of the screw 6 of the extruder 1 satisfy The above-mentioned formula (2) may be satisfied, and the following formula (5) is preferably satisfied, and the following formula (6) is more preferably satisfied. When the value of “C _A × S _D × S _S × S _P ” is too small, the productivity decreases, on the other hand, when the value of “C _A × S _D × S _S × S _P ” is too large, the production In the case of the obtained rubber cross-linked product, the surface state deteriorates.

4.5×10 ⁶ ≤C _A ×S _D ×S _S ×S _P ≤7.6×10 ⁶ (5)

5.0×10 ⁶ ≤C _A ×S _D ×S _S ×S _P ≤7.1×10 ⁶ (6)

The diameter _SD of the screw 6 of the extrusion molding machine 1 is the outer diameter of the screw 6 of the extrusion molding machine 1 (the diameter of the portion of the screw portion of the screw groove and the portion of the screw flight of the screw 6), The value of “C _A × S _D × S _S × S _P ” may satisfy the above formula (2). The diameter S _D of the screw 6 of the extrusion molding machine 1 is preferably 20 to 200 mm, more preferably 30 to 150 mm, It is more preferably 50 to 100 mm, and particularly preferably 65 to 85 mm.

The rotational speed S _S of the screw 6 of the extrusion molding machine 1 is the rotational speed of the screw 6 when the acrylic rubber composition is extruded, and is preferably 5 to 60 rpm, more preferably 10 to 50 rpm, and even more preferably 15 to 45 rpm.

In addition, the total pitch number _SP of the screw 6 of the extrusion molding machine 1 is the total number of parts constituting the flight of the screw 6, and is preferably 10 to 50, more preferably 15 to 45, still more preferably 20 to 40, and particularly preferably 27 to 37. In addition, for example, when the total pitch number _SP of the screw 6 of the extrusion molding machine 1 is 32, that is, the total number of portions of the flight of the screw 6 in the longitudinal direction of the screw 6 is 32.

In addition, other conditions during extrusion molding by the extrusion molding machine 1 are not particularly limited. For example, the length _SL of the screw 6 is preferably 400 to 3000 mm, more preferably 700 to 2500 mm, still more preferably 1000 to 2000 mm, It is especially preferable that it is 1050-1350 mm. In addition, the groove depth of the screw 6 is not particularly limited, but is preferably 4 to 12 mm, more preferably 5 to 11 mm, and even more preferably 6 to 10 mm.

In addition, the temperature of the screw 6 during extrusion molding by the extrusion molding machine 1 is not particularly limited, but is preferably 50 to 110° C., more preferably 60 to 100° C., still more preferably 70 to 100° C. The temperature of the cylindrical body is preferably 50 to 110°C, more preferably 60 to 100°C, further preferably 70 to 100°C. Furthermore, the temperature of the die head 5 is preferably 60 to 120°C, more preferably 70 to 110°C, still more preferably 80 to 110°C.

<Rubber cross-linked product>

The rubber cross-linked product of the present invention is obtained by cross-linking the rubber molded body obtained by the above-described production method of the present invention.

The cross-linked rubber of the present invention can be produced by subjecting the rubber molded body obtained by the above-described production method of the present invention to a cross-linking reaction by heating and curing the shape into a cross-linked rubber. The crosslinking temperature is usually 130 to 220°C, preferably 150 to 190°C, and the crosslinking time is usually 2 minutes to 10 hours, preferably 3 minutes to 5 hours. As the heating method, methods that can be used for rubber crosslinking, such as oven heating, steam heating, microwave heating, and hot air heating, can be appropriately selected. For example, when the rubber molded body is in the shape of a hose, a mandrel is inserted into the inside of the hose-shaped rubber molded body, and the mandrel is inserted into the mandrel and heated to obtain a rubber cross-linked product.

In addition, depending on the shape, size, etc. of the cross-linked rubber, the cross-linked rubber of the present invention may be further heated for secondary cross-linking. The secondary crosslinking varies depending on the heating method, crosslinking temperature, shape, and the like, but is preferably performed for 1 to 48 hours. The heating method and heating temperature may be appropriately selected.

Furthermore, the rubber cross-linked product of the present invention thus obtained can be preferably used for, for example, oil hoses such as oil hoses, ATF hoses, brake hoses, etc., turbo air hoses, transmission control hoses, exhaust hoses, and the like. Various hoses such as air hoses, radiator hoses, heater hoses, and air conditioner hoses.

Example

Hereinafter, an Example and a comparative example are given and this invention is demonstrated concretely. Hereinafter, unless otherwise specified, "parts" are based on weight. In addition, the test and evaluation were performed as follows.

<Monomer composition of acrylic rubber>

The composition of each monomer unit contained in the acrylic rubber was confirmed by ¹ H-NMR measurement, and the content of carboxyl groups in the acrylic rubber was calculated by dissolving the acrylic rubber in acetone and performing potentiometric titration with a potassium hydroxide solution.

<Mooney viscosity (ML1+4, 100℃)>

The Mooney viscosity (ML1+4, 100°C) of acrylic rubber at a measurement temperature of 100°C was measured in accordance with the Mooney viscosity test of the physical test method for uncrosslinked rubber in JIS K6300.

<Surface state of rubber molded body and rubber cross-linked product>

The surface states of the rubber molded body and the rubber cross-linked product were visually observed and evaluated according to the following criteria.

○: The surface is smooth and glossy.

Δ: Neither concavities and convexities nor small wrinkles were observed on the surface, but no gloss was observed.

×: Concavities and convexities or small wrinkles are observed on the surface.

<Extrusion amount of extrusion molding>

The extrusion weight per 20 seconds (g/20 seconds) at the time of extrusion molding using the acrylic rubber composition was measured as the extrusion amount. The larger the value of the extrusion amount, the more excellent the productivity can be judged. In addition, the extrusion amount is shown as a relative value when the value of Comparative Example 2 is taken as 100.

<Discharge temperature of rubber molded body>

During extrusion molding using the acrylic rubber composition, the temperature of the rubber molded body discharged from the die 5 was measured with a contact thermometer.

<Production Example 1>

(Manufacture of acrylic rubber)

200 parts of water, 2 parts of sodium lauryl sulfate, 64 parts of ethyl acrylate and 34.6 parts of n-butyl acrylate were added to a polymerization reactor with a thermometer and stirring device, and degassing and degassing under reduced pressure were carried out for three times. After nitrogen replacement to fully remove oxygen, 1.4 parts of mono-n-butyl fumarate and 0.006 parts of p-terpine hydroperoxide were added, and emulsion polymerization was started at normal pressure and temperature of 20°C, and the reaction was carried out for 5 hours. The polymerization conversion rate reached about 90%. Then, the obtained emulsion polymerization liquid was coagulated with a calcium chloride solution, washed with water, and dried to obtain an acrylic rubber. The polymer composition of the obtained acrylic rubber was 64.0% by weight of ethyl acrylate units, 34.6% by weight of n-butyl acrylate units, and 1.4% by weight of mono-n-butyl fumarate units. Moreover, the Mooney viscosity (ML1+4, 100 degreeC) of the obtained acrylic rubber was 33.

<Example 1>

(Preparation of Acrylic Rubber Composition)

To 100 parts of the acrylic rubber obtained in Production Example 1, 65 parts of HAF carbon black (trade name "Seast3", manufactured by Tokai Carbon Co., Ltd., DBP oil absorption value: 101 cc/100 g), 5 Part of plasticizer (trade name "ADKCIZER RS735", manufactured by ADEKA Corporation), 2 parts of stearic acid, 1 part of ester wax (product name "Greg G-8205", manufactured by Dainippon Ink Chemical Co., Ltd., lubricant), 2 parts of 4,4'-bis(α,α-dimethylbenzyl)diphenylamine (trade name "NocracCD", manufactured by Ouchi Shinshin Chemical Industry Co., Ltd., antioxidant) and 1 part of primary Alkylamine (trade name "lipomin 18D", manufactured by Lion Specialty Chemicals Co., Ltd.) was mixed at 50°C for 5 minutes. Next, the resulting mixture was transferred to a roll mixer at 50°C. 0.5 parts of hexamethylene diamine carbamate (trade name "Diak #1", manufactured by DuPont Dow Elastomers, aliphatic polyamine compound) as a cross-linking agent and 2 parts of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) (trade name "RHENOGRAN XLA-60", manufactured by Rheinland Chemical Co., Ltd., DBU60% (including part of zinc phosphate)), and kneading to obtain an acrylic rubber composition.

Next, the acrylic rubber composition obtained above was extruded using a uniaxial extrusion molding machine 1 (trade name "EMR-V75D16", manufactured by EM Giken Co., Ltd.) shown in FIG. Tubular rubber molding. In addition, the conditions of extrusion molding are as follows.

The compounding amount of carbon black C _A : 65phr

DBP oil absorption value C _D of carbon black: 101cc/100g

Diameter S _D of screw 6 of extruder 1: 75mm

The rotational speed S _S of the screw 6 of the extruder 1: 30 rpm

Total pitch number SP of screw 6 of _extruder 1: 32

The shape of the screw 6 of the extrusion molding machine 1: a full-flight type bidirectional screw

The groove depth of the screw 6 of the extrusion molding machine 1: 7.5mm

Thread pitch of screw 6 of extrusion molding machine 1: 75mm

Length _SL of screw 6 of extruder 1: 1200mm

Temperature of screw 6 of extruder 1: 80°C

The temperature of the barrel constituting the barrel 3 of the extrusion molding machine 1: 80°C

Temperature of die 5 of extrusion molding machine 1: 90°C

Die diameter of die 5: 33mm

Nozzle diameter of die 5: 30mm

Then, the extrusion amount at the time of extrusion molding and the surface state of the obtained hose-shaped rubber molded body were evaluated according to the above-mentioned method. The results are shown in Table 1.

Next, the obtained hose-shaped rubber molded body was cut into a length of 50 mm, and a metal rod (mandrel) of 30 mmφ made of SUS was inserted into the inner surface side of the cut hose-shaped rubber molded body to insert a SUS-made metal rod (mandrel). The state of the metal rod was heated in an oven at 170° C. for 1 hour, thereby obtaining a rubber cross-linked product in the form of a hose. Then, with respect to the obtained cross-linked rubber, the surface state of the cross-linked rubber was evaluated according to the method described above. The results are shown in Table 1.

<Example 2, Example 3>

_A rubber molded body and a rubber compound were obtained in the same manner as in Example 1, except that one of the compounding amount CA of the HAF carbon black and the rotational speed S _S of the screw 6 of the extruder 1 was changed as shown in Table 1. The conjugates were evaluated in the same manner. The results are shown in Table 1.

<Comparative Examples 1 to 6>

_A rubber molded body was obtained in the same manner as in Example 1, except that one or both of the compounding amount CA of the HAF carbon black and the rotational speed S _S of the screw 6 of the extruder 1 were changed as shown in Table 1. Evaluation was performed in the same manner as the rubber cross-linked product. The results are shown in Table 1.

[Table 1]

<Example 4>

Except having used 50 parts of MAF carbon black (trade name "Seast116", manufactured by Tokai Carbon Co., Ltd., DBP oil absorption value: 135 cc/100 g) in place of 65 parts of HAF carbon black, a rubber molded body and a rubber molded body were obtained in the same manner as in Example 1. The rubber cross-linked product was evaluated in the same manner. The results are shown in Table 2.

<Examples 5 to 8>

_A rubber molded body was obtained in the same manner as in Example 4, except that one or both of the compounding amount CA of MAF carbon black and the rotational speed S _S of the screw 6 of the extruder 1 were changed as shown in Table 2. Evaluation was performed in the same manner as the rubber cross-linked product. The results are shown in Table 2.

<Comparative Examples 7 to 12>

_A rubber molded body was obtained in the same manner as in Example 4, except that one or both of the compounding amount CA of MAF carbon black and the rotational speed S _S of the screw 6 of the extruder 1 were changed as shown in Table 2. Evaluation was performed in the same manner as the rubber cross-linked product. The results are shown in Table 2.

[Table 2]

<Example 9>

A rubber molded body was obtained in the same manner as in Example 1, except that 65 parts of FEF carbon black (trade name "Seast SO", manufactured by Tokai Carbon Co., Ltd., DBP oil absorption value: 115 cc/100 g) was used instead of 65 parts of HAF carbon black Evaluation was carried out in the same manner as the rubber cross-linked product. The results are shown in Table 3.

<Example 10, Example 11>

_A rubber molded body was obtained in the same manner as in Example 9, except that one or both of the blending amount CA of FEF carbon black and the rotational speed S _S of the screw 6 of the extrusion molding machine 1 were changed as shown in Table 3. Evaluation was performed in the same manner as the rubber cross-linked product. The results are shown in Table 3.

<Comparative Examples 13 to 18>

_A rubber molded body was obtained in the same manner as in Example 9, except that one or both of the blending amount CA of FEF carbon black and the rotational speed S _S of the screw 6 of the extrusion molding machine 1 were changed as shown in Table 3. Evaluation was performed in the same manner as the rubber cross-linked product. The results are shown in Table 3.

[table 3]

<Comparative Example 19>

50 parts of SRF carbon black (trade name "Seast S", manufactured by Tokai Carbon Co., Ltd., DBP oil absorption value: 68 cc/100 g) was used in place of 65 parts of HAF carbon black, and the rotation speed S of the screw 6 of the extrusion molding machine 1 was adjusted to S Except having changed _S to 15 rpm, it carried out similarly to Example 1, and obtained the rubber molded object and the rubber cross-linked product, and evaluated it similarly. The results are shown in Table 4.

<Comparative Examples 20 to 27>

_A rubber molded body was obtained in the same manner as in Comparative Example 19, except that one or both of the compounding amount CA of the SRF carbon black and the rotational speed S _S of the screw 6 of the extrusion molding machine 1 were changed as shown in Table 4. Evaluation was performed in the same manner as the rubber cross-linked product. The results are shown in Table 4.

[Table 4]

As shown in Tables 1 to 4, the acrylic rubber composition satisfies the conditions of "6.5×10 ³ ≤C _A ×C _D ≤1.1×10 ⁴ ” and When extrusion molding was performed under the conditions of “3.2×10 ⁶ ≤C _A ×S _D ×S _S ×SP _≤8.0 ×10 ⁶ ”, both the obtained rubber molded body and the rubber cross-linked product had excellent surface states , and the extrusion amount during extrusion molding was also large, and the productivity was excellent (Examples 1 to 11).

On the other hand, the acrylic rubber composition does not satisfy the conditions of “6.5×10 ³ ≤C _A ×C _D ≤1.1×10 ⁴ ” and “3.2×10 ⁶ ” at the time of extrusion molding using an extruder. ≤C _A x S _D x S _S x S _P ≤ 8.0 x 10 ⁶ ” in either or both of the conditions, the result is either the obtained rubber molded body or the rubber cross-linked body Either the surface states of both were poor, or as a result, the extrusion amount during extrusion molding was small, and the productivity was poor (Comparative Examples 1 to 27).

Description of reference numerals

1: Extruder;

2: drive unit;

3: barrel;

31～41: barrel block;

5: Die head;

6: Screw.

Claims (7)

1. A method for producing a rubber molded body by molding an acrylic rubber composition containing a rubber component containing an acrylic rubber, carbon black and a crosslinking agent using an extrusion molding machine,

c represents the compounding amount of carbon black contained in the acrylic rubber composition _A [phr]Setting the DBP oil absorption value of the carbon black to C _D [cc/100g]And the diameter of the screw of the extrusion molding machine is set as S _D [mm]Setting the rotation speed of the screw of the extrusion molding machine to S _S [rpm]Setting the total pitch number of the screw of the extrusion molding machine as S _P In the case of (A), the following formula (A) is satisfied1) And the acrylic rubber composition is molded by the extrusion molding machine in the following formula (2),

6.5×10 ³ ≤C _A ×C _D ≤1.1×10 ⁴ (1)

3.2×10 ⁶ ≤C _A ×S _D ×S _S ×S _P ≤8.0×10 ⁶ (2)。

2. the method for producing a rubber molded body according to claim 1, wherein the acrylic rubber contains a (meth) acrylate monomer unit and a crosslinkable monomer unit,

the content of the (meth) acrylate monomer unit in the monomer units constituting the acrylic rubber is 50 wt% or more, and the content of the crosslinkable monomer unit is 0.1 wt% or more.

3. The method for producing a rubber molded body according to claim 2, wherein the crosslinkable monomer unit is a unit of an α, β -ethylenically unsaturated carboxylic acid monomer.

4. The method for producing a rubber molded body according to claim 3, wherein the crosslinkable monomer unit is a unit of an α, β -ethylenically unsaturated dicarboxylic acid monoester monomer.

5. The method for producing a rubber molded body according to any one of claims 1 to 3, wherein the amount C of carbon black blended is _A 40 to 120 phr.

6. The method for producing a rubber molded body according to any one of claims 1 to 5, wherein the extrusion molding machine is a uniaxial extrusion molding machine.

7. A method for producing a crosslinked rubber product, comprising the step of obtaining a rubber molded product by the production method according to any one of claims 1 to 6, and the step of crosslinking the rubber molded product.

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