KR102756240B1 - Acryl based copolymer, method for preparing the same and acryl based copolymer composition comprising the acryl based copolymer - Google Patents

Abstract

The present invention relates to an acrylic copolymer, and more specifically, to an acrylic copolymer including a repeating unit derived from a main monomer and a cross-linking moiety derived from a first cross-linking agent, wherein the repeating unit derived from the main monomer includes a repeating unit derived from a (meth)acrylic acid alkyl ester monomer, a repeating unit derived from a (meth)acrylic acid alkoxy alkyl ester monomer, and a repeating unit derived from a cross-linkable monomer, wherein the first cross-linking agent includes a metal salt compound of a saturated fatty acid and a metal salt compound of a dicarboxylic acid, and wherein the cross-linking moiety derived from the first cross-linking agent is included in an amount of 0.1 to 0.5 parts by weight based on 100 parts by weight of the total repeating unit derived from the main monomer.

Description

Acrylic copolymer, method for preparing the same and acrylic copolymer composition comprising the same {ACRYL BASED COPOLYMER, METHOD FOR PREPARING THE SAME AND ACRYL BASED COPOLYMER COMPOSITION COMPRISING THE ACRYL BASED COPOLYMER}

The present invention relates to an acrylic copolymer, and more specifically, to a method for producing an acrylic copolymer, an acrylic copolymer composition including the acrylic copolymer having excellent stress relaxation properties and extrusion processability, and a molded article having excellent mechanical properties.

Rubber parts used in automobiles account for only 5% of the total weight of the vehicle, but they are mainly used in important parts that determine the performance of the automobile. Due to their characteristics, they are important parts that are applied to parts that generate vibration and noise, and parts that require heat and oil resistance. In particular, in the case of small car engines that require high power, materials with excellent heat and oil resistance are required.

Among various special rubbers, acrylic rubber is a rubber that has (meth)acrylic acid alkyl ester as its main monomer unit, and has excellent heat resistance and oil resistance. Therefore, it is not only used as a component material for seals, hoses, tubes, and belts in the automobile-related field, but is also widely used as an adhesive and as a material for rubber parts. Acrylic rubber is crosslinked to provide elasticity so that it can be used as a rubber part, and for this purpose, a crosslinking monomer having an active crosslinking point is copolymerized. Crosslinked acrylic rubber copolymerized with such crosslinking monomers is generally manufactured by mixing fillers such as carbon black or a crosslinking agent to produce a crosslinked acrylic rubber composition, and is molded into a molded product having a desired shape, and is used for various purposes.

Crosslinked acrylic rubber, which is used for various purposes, is used to manufacture molded products through extrusion molding, and it is preferred that the surface of the molded product be good. In order to improve the surface of the molded product, stress relaxation can be improved, and to improve this, the pattern viscosity is generally lowered. However, if the pattern viscosity is lowered, the mechanical strength tends to be lowered.

Therefore, there is a demand for the production of acrylic rubber with excellent stress relaxation properties while maintaining mechanical strength by improving pattern viscosity.

KR 2019-0007922 A

The problem to be solved in the present invention is to manufacture an acrylic copolymer, and to provide an acrylic copolymer composition having excellent stress relaxation properties and extrusion processability, and a molded product having excellent mechanical properties, in order to solve the problems mentioned in the background technology of the above invention.

According to one embodiment of the present invention for solving the above problems, the present invention provides an acrylic copolymer including a repeating unit derived from a main monomer and a cross-linking moiety derived from a first cross-linking agent, wherein the repeating unit derived from the main monomer includes a repeating unit derived from a (meth)acrylic acid alkyl ester monomer, a repeating unit derived from a (meth)acrylic acid alkoxy alkyl ester monomer, and a repeating unit derived from a cross-linkable monomer, wherein the first cross-linking agent includes a metal salt compound of a saturated fatty acid and a metal salt compound of a dicarboxylic acid, and the cross-linking moiety derived from the first cross-linking agent is included in an amount of 0.1 to 0.5 parts by weight based on 100 parts by weight of the total repeating unit derived from the main monomer.

In addition, the present invention provides a method for producing an acrylic copolymer, including a step (S10) of producing a main monomer mixture including a (meth)acrylic acid alkyl ester monomer, a (meth)acrylic acid alkoxy alkyl ester monomer, and a crosslinking monomer; and a step (S20) of introducing a first crosslinking agent into the main monomer mixture and polymerizing it, wherein the first crosslinking agent includes a metal salt compound of a saturated fatty acid and a metal salt compound of a dicarboxylic acid, and the first crosslinking agent is used in an amount of 0.1 to 0.5 parts by weight based on 100 parts by weight of the total main monomer mixture.

In addition, the present invention provides an acrylic copolymer composition comprising an acrylic copolymer and a filler according to the present invention.

By including an acrylic copolymer containing a crosslinking agent according to the present invention, an acrylic copolymer composition having excellent stress relaxation properties and extrusion processability and a molded article manufactured from the composition having excellent mechanical properties can be provided.

The terms or words used in the description and claims of the present invention should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of the present invention, based on the principle that the inventor can appropriately define the concept of the term in order to explain his or her own invention in the best manner.

In the present invention, the term 'monomer-derived repeating unit' may indicate a component, structure, or substance itself derived from a monomer, and as a specific example, may mean a repeating unit formed within a polymer by a monomer introduced during polymerization of the polymer and participating in the polymerization reaction.

In the present invention, the term 'cross-linking part derived from a cross-linking agent' may indicate a component, structure, or substance itself derived from a compound used as a cross-linking agent, and as a specific example, may mean a cross-linking part that performs a cross-linking role within a polymer or between polymers formed by the action and reaction of a cross-linking agent.

In the present invention, the term 'copolymer' may mean all copolymers formed by copolymerizing comonomers, and as specific examples, may mean all of alternating copolymers, random copolymers, and block copolymers.

In the present invention, the term 'rubber' refers to a plastic material having elasticity, and may mean rubber, elastomer, or synthetic latex.

Hereinafter, the present invention will be described in more detail to help understand the present invention.

The acrylic copolymer according to the present invention may include a repeating unit derived from a main monomer and a crosslinking portion derived from a first crosslinking agent.

According to one embodiment of the present invention, the repeating unit derived from the main monomer may include a repeating unit derived from a (meth)acrylic acid alkyl ester monomer, a repeating unit derived from a (meth)acrylic acid alkoxy alkyl ester monomer, and a crosslinking monomer.

According to one embodiment of the present invention, the repeating unit derived from the (meth)acrylic acid alkyl ester monomer is a component that controls the glass transition temperature in an acrylic copolymer to increase workability, heat resistance and cold resistance in a final product, and may include a (meth)acrylic acid alkyl ester monomer containing an alkyl group having 1 to 8 carbon atoms. In this case, the alkyl group having 1 to 8 carbon atoms may mean a linear or cyclic alkyl group having 1 to 8 carbon atoms. As a specific example, the (meth)acrylic acid alkyl ester monomer may be methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, n-amyl (meth)acrylate, isoamyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, etc. Here, the (meth)acrylic acid alkyl ester monomer may be used alone or in combination of two or more, and as a more specific example, the (meth)acrylic acid alkyl ester monomer may include ethyl (meth)acrylate and n-butyl (meth)acrylate monomers.

The content of the (meth)acrylic acid alkyl ester monomer-derived repeating unit in the above-mentioned main monomer-derived repeating unit may be 65 wt% to 93 wt%, 75 wt% to 90 wt%, or 80 wt% to 90 wt%, and within this range, the acrylic copolymer according to the present invention has excellent workability, heat resistance, oil resistance, and cold resistance.

The above (meth)acrylic acid alkoxy alkyl ester monomer-derived repeating unit is a component that controls the glass transition temperature in an acrylic copolymer and increases workability, heat resistance and cold resistance in a final product, and may refer to a (meth)acrylic acid alkyl ester monomer containing an alkoxyalkyl group having 1 to 8 carbon atoms. As a specific example, the (meth)acrylic acid alkoxy alkyl ester monomer may be (meth)acrylic acid methoxymethyl, (meth)acrylic acid ethoxymethyl, (meth)acrylic acid 2-ethoxyethyl, (meth)acrylic acid 2-butoxyethyl, (meth)acrylic acid 2-methoxyethyl, (meth)acrylic acid 2-propoxyethyl, (meth)acrylic acid 3-methoxy propyl, (meth)acrylic acid 4-methoxybutyl, etc. As a specific example, the (meth)acrylic acid alkoxy alkyl ester monomer may include (meth)acrylic acid 2-methoxyethyl.

The content of the repeating unit derived from the (meth)acrylic acid alkoxy alkyl ester monomer in the repeating unit derived from the main monomer may be 5 wt% to 30 wt%, 7 wt% to 25 wt%, or 10 wt% to 20 wt%, and within this range, the workability and oil resistance of the acrylic copolymer according to the present invention are excellent.

Meanwhile, the total content of the (meth)acrylic acid alkyl ester monomer-derived repeating unit and the (meth)acrylic acid alkoxy alkyl ester monomer-derived repeating unit included in the main monomer-derived repeating unit may be 80 wt% to 99.9 wt%, 85 wt% to 99.9 wt%, or 90 wt% to 99.5 wt%, and within this range, the acrylic copolymer according to the present invention has excellent workability, cold resistance, and heat resistance.

The above crosslinkable monomer-derived repeating unit is a component for providing a crosslinkable functional group in an acrylic copolymer, and may include at least one selected from the group consisting of a butenedioic acid monoester monomer, an epoxy group-containing monomer, and a halogen-containing monomer.

The above butenedioic acid monoester monomer may be a maleic acid monoester monomer or a fumaric acid monoester monomer obtained by reacting a carboxyl group of butenedioic acid, i.e. maleic acid or fumaric acid, with an alcohol. The above maleic acid monoester monomers may be maleic acid monoalkyl ester monomers such as maleic acid monomethyl, maleic acid monoethyl, maleic acid monopropyl, maleic acid monobutyl, maleic acid monopentyl, and maleic acid monodecyl; maleic acid monocyclopentyl, maleic acid monocyclohexyl, maleic acid monocycloheptyl, maleic acid monocyclooctyl, maleic acid monomethyl cyclohexyl, maleic acid mono-3,5-dimethylcyclohexyl, maleic acid monodicyclopentanyl, and maleic acid monoisobornyl; maleic acid monocycloalkenyl ester monomers such as maleic acid monocyclopentenyl, maleic acid monocyclohexenyl, maleic acid monocycloheptenyl, maleic acid monocyclooctenyl, and maleic acid dicyclopentadienyl; etc. The above fumaric acid monoester monomers may be fumaric acid monoalkyl ester monomers such as fumaric acid monomethyl, fumaric acid monoethyl, fumaric acid monopropyl, fumaric acid monobutyl, fumaric acid monohexyl, and fumaric acid monooctyl; fumaric acid monocycloalkyl ester monomers such as fumaric acid monocyclopentyl, fumaric acid monocyclohexyl, fumaric acid monocycloheptyl, fumaric acid monocyclooctyl, fumaric acid monomethyl cyclohexyl, fumaric acid mono-3,5-dimethylcyclohexyl, fumaric acid dicyclopentanyl, and fumaric acid isobornyl; fumaric acid monocycloalkenyl ester monomers such as fumaric acid monocyclopentenyl, fumaric acid monocyclohexenyl, fumaric acid monocycloheptenyl, fumaric acid monocyclooctenyl, and fumaric acid monodicyclopentadienyl.

The above epoxy group-containing monomer may be glycidyl (meth)acrylate, vinyl glycidyl ether, allyl glycidyl ether, methacryl glycidyl ether, etc. As a specific example, the above epoxy group-containing monomer may be glycidyl (meth)acrylate, allyl glycidyl ether, etc.

The above halogen-containing monomers may be vinylchloroacetate, vinyl bromo acetate, allyl chloro acetate, vinyl chloro propionate, vinyl chloro butylate, vinyl bromo butylate, 2-chloro ethyl acrylate, 3-chloro propyl acrylate, 4-chlorobutyl acrylate, 2-chloro ethyl methacrylate, 2-bromo acrylate, 2-iodo acrylate ethyl, 2-chloroethyl vinyl ether, chloro methyl vinyl ether, 4-chloro-2-butenyl acrylate, vinyl benzyl chloride, 5-chloromethyl-2-norbornene, 5-chloroacetoxy methyl-2-norbornene, and the like. As specific examples, the halogen-containing monomers may be vinylchloroacetate, vinyl benzyl chloride, 2-chloro ethyl acrylate, 2-chloroethyl vinyl ether, and the like.

The content of the crosslinkable monomer-derived repeating unit in the above-mentioned main monomer-derived repeating unit may be 0.1 wt% to 20 wt%, 0.1 wt% to 15 wt%, or 0.5 wt% to 10 wt%, and within this range, the crosslinking density of the acrylic copolymer according to the present invention is high, the elongation of the obtained crosslinked product is improved, and the mechanical properties of a molded article molded from the acrylic copolymer are excellent, and there is an effect of preventing compression set.

According to one embodiment of the present invention, the main monomer-derived repeating unit may further include, in addition to the (meth)acrylic acid alkyl ester monomer-derived repeating unit, the (meth)acrylic acid alkoxy alkyl ester monomer-derived repeating unit, and the crosslinkable monomer-derived repeating unit, another monomer-derived repeating unit copolymerizable with the (meth)acrylic acid alkyl ester monomer-derived repeating unit and the (meth)acrylic acid alkoxy alkyl ester monomer-derived repeating unit.

According to one embodiment of the present invention, the acrylic copolymer according to the present invention may include a repeating unit derived from the main monomer described above, and a crosslinking portion derived from the first crosslinking agent.

The above first cross-linking agent is a reactive cross-linking agent including a metal salt compound of a saturated fatty acid and a metal salt compound of a dicarboxylic acid, and may be, for example, a mixture of a metal salt compound of a saturated fatty acid and a metal salt compound of a dicarboxylic acid, and for example, the cross-linking agent may include 50 to 80 wt%, 50 to 70 wt%, or 55 to 65 wt% of the metal salt compound of a saturated fatty acid, and 20 to 50 wt%, 30 to 50 wt%, or 35 to 45 wt% of the metal salt compound of a dicarboxylic acid. Within this range, there is an effect of improving the mechanical properties of a molded product manufactured from the core-shell copolymer.

Meanwhile, an acrylic copolymer according to one embodiment of the present invention can have a copolymer structure having a high crosslinking rate by including a mixture of a metal salt compound of a fatty acid having a small number of double bonds in the chain and a long carbon chain and a metal salt compound of a gemini-type dicarboxylic acid as a first crosslinking agent, thereby enabling more stable and easy crosslinking.

The metal salt compound of the above saturated fatty acid may be a compound represented by the following chemical formula 1.

[Chemical Formula 1]

In the above chemical formula 1,

M is sodium or potassium, and n can be an integer from 10 to 30.

As a specific example, in the chemical formula 1, M may be sodium or potassium, and n may be an integer from 12 to 20. As a more specific example, the saturated fatty acid metal salt compound may be sodium stearate or potassium stearate. In this case, there is an effect of improving the extrusion processability of the acrylic copolymer composition including the core-shell copolymer.

In addition, the metal salt compound of the above dicarboxylic acid may be a compound represented by the following chemical formula 2.

[Chemical formula 2]

In the above chemical formula 2,

M ₁ and M ₂ are the same or different and each independently an alkali metal,

L ₁ and L ₂ are the same or different, and each independently an alkylene group having 1 to 15 carbon atoms,

X is a cycloalkenylene group having 1 to 20 carbon atoms, substituted with 1 or more alkyl groups having 1 to 10 carbon atoms.

As a specific example, in the chemical formula 2, M ₁ and M ₂ are sodium, L ₁ and L ₂ are each independently an alkylene group having 3 to 10 carbon atoms, and X may be a cycloalkenylene group having 6 to 12 carbon atoms and having at least one ring, substituted with at least one alkyl group having 1 to 10 carbon atoms. As a more specific example, the metal salt compound of the dicarboxylic acid may be a compound represented by the following chemical formula 3. In this case, there is an effect of improving the extrusion processability of the acrylic copolymer composition including the core-shell copolymer.

[Chemical Formula 3]

In the above chemical formula 3,

M ₃ and M ₄ are the same or different and each independently an alkali metal.

The content of the crosslinking portion derived from the first crosslinking agent may be 0.1 to 0.5 parts by weight, 0.1 to 0.4 parts by weight, or 0.1 to 0.3 parts by weight based on 100 parts by weight of the total repeating unit derived from the main monomer, and within this range, the stress relaxation property of the acrylic copolymer according to the present invention is improved, thereby providing excellent surface properties.

According to one embodiment of the present invention, the acrylic copolymer according to the present invention may further include a cross-linking unit derived from a second cross-linking agent in addition to the repeating unit derived from the aforementioned main monomer and the cross-linking unit derived from the first cross-linking agent.

The second cross-linking agent is used simultaneously with the first cross-linking agent to improve the cross-linking density of the copolymer, and at the same time, effectively induces coagulation during the coagulation process of the acrylic copolymer, thereby facilitating mixing with a filler after coagulation, thereby further improving the extrusion processability of the acrylic copolymer composition formed after mixing, and has the effect of improving the tensile strength of a molded product molded from the acrylic copolymer composition including the same.

The second cross-linking agent may be an ethoxylate bisphenol A di(meth)acrylate containing 2 to 20 repeating units of ethoxy groups (-OCH ₂ CH ₃ ). That is, the second cross-linking agent may be a compound represented by the following chemical formula 4.

[Chemical Formula 4]

In the above chemical formula 4,

m + n is an integer between 2 and 20.

As a specific example, the second cross-linking agent may be an ethoxylate bisphenol A di(meth)acrylate having 5 to 15 ethoxy groups in the repeating unit, i.e., m + n in the chemical formula 4 may be 5 to 15. As a more specific example, the second cross-linking agent may be an ethoxylate bisphenol A (EO)10 Dimethacrylate having 10 ethoxy groups in the repeating unit, i.e., m + n in the chemical formula 4 may be 10. In this case, the patterned viscosity of the acrylic copolymer increases while providing excellent stress relaxation properties.

The cross-linking portion derived from the second cross-linking agent may be included in an amount of 0.05 to 0.1, 0.05 to 0.09, or 0.05 to 0.08 parts by weight based on 100 parts by weight of the total repeating unit derived from the main monomer. Within this range, coagulation of the acrylic copolymer can be effectively induced, and the extrusion processability of the acrylic copolymer composition including the acrylic copolymer is improved.

The weight average molecular weight of the acrylic copolymer may be 200,000 g/mol to 4,000,000 g/mol, 300,000 g/mol to 3,000,000 g/mol, or 500,000 g/mol to 2,500,000 g/mol. Within this range, the manufacturing time of the acrylic copolymer according to the present invention is reduced, and a molded article manufactured from the acrylic copolymer has the effect of being able to implement excellent mechanical properties.

According to one embodiment of the present invention, the patterned viscosity (ML ₁₊₄ , 100° C.) of the acrylic copolymer may be 10 to 70, 20 to 60, or 25 to 50. Within this range, excellent workability is achieved.

According to the present invention, a method for producing an acrylic copolymer is provided. The method for producing the acrylic copolymer includes a step (S10) of producing a main monomer mixture including a (meth)acrylic acid alkyl ester monomer, a (meth)acrylic acid alkoxy alkyl ester monomer, and a crosslinking monomer; and a step (S20) of adding a first crosslinking agent to the main monomer mixture and polymerizing it, wherein the first crosslinking agent includes a metal salt compound of a saturated fatty acid and a metal salt compound of a dicarboxylic acid, and the first crosslinking agent can be used in an amount of 0.1 to 0.5 parts by weight based on 100 parts by weight of the total main monomer mixture.

The step (S10) of preparing the main monomer mixture may be a step for preparing the main chain of an acrylic copolymer, and the type and content of the main monomer mixture forming monomers introduced in the step of preparing the main monomer mixture may be the same as the type and content of the monomers for forming the main monomer-derived repeating unit described above.

In addition, the step (S20) of introducing and polymerizing the first cross-linking agent may be a polymerization step for obtaining an acrylic copolymer, and the type and content of the introduced first cross-linking agent may be the same as the type and content of the cross-linking agent for forming a cross-linking portion derived from the first cross-linking agent described above.

In addition, in the step (S20), a second cross-linking agent may be further added, and in this case, the second cross-linking agent is used together with the first cross-linking agent to further induce cross-linking between monomers, thereby significantly improving the cross-linking density and effectively inducing coagulation of the acrylic copolymer. The type and content of the second cross-linking agent added may be the same as the type and content of the cross-linking agent for forming a cross-linked portion derived from the second cross-linking agent described above.

The above acrylic copolymer can be produced using methods such as emulsion polymerization, bulk polymerization, suspension polymerization, and solution polymerization, and can be produced by using additional additives such as an initiator, an emulsifier, a polymerization terminator, an ion exchange water, a molecular weight regulator, an activator, and a redox catalyst, and can be produced using emulsion polymerization methods such as batch, semi-batch, and continuous.

The above initiator may be, for example, inorganic peroxides such as sodium persulfate, potassium persulfate, ammonium persulfate, potassium perphosphate, and hydrogen peroxide; organic peroxides such as diisopropylbenzene hydroperoxide, t-butyl hydroperoxide, cumene hydroperoxide, p-menthane hydroperoxide, di-t-butyl peroxide, t-butylcumyl peroxide, acetyl peroxide, isobutyl peroxide, octanoyl peroxide, benzoyl peroxide, 3,5,5-trimethylhexanol peroxide, and t-butyl peroxy isobutyrate; nitrogen compounds such as azobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile, azobiscyclohexanecarbonitrile, and azobisisobutyric acid methyl. These polymerization initiators can be used alone or in combination of two or more. These initiators can be used in an amount of 0.005 to 0.2 parts by weight based on 100 parts by weight of the entire main monomer mixture.

Meanwhile, an organic peroxide or inorganic peroxide initiator can be used as a redox polymerization initiator in combination with a reducing agent. The reducing agent is not particularly limited, but may include compounds containing metal ions in a reduced state, such as ferrous sulfate and cuprous naphthenate; sulfonic acid compounds, such as sodium methanesulfonate; amine compounds, such as dimethylaniline; and the like. These reducing agents can be used singly or in combination of two or more. The reducing agent can be used in an amount of 0.03 to 20 parts by weight relative to 1 part by weight of the peroxide.

The above emulsifier may be at least one selected from the group consisting of anionic emulsifiers, cationic emulsifiers, and nonionic emulsifiers, and specific examples thereof include nonionic emulsifiers such as polyoxyethylene alkyl ethers, polyoxyethylene alkylphenol ethers, polyoxyethylene alkyl esters, and polyoxyethylene sorbitan alkyl esters; anionic emulsifiers such as salts of fatty acids such as myristic acid, palmitic acid, oleic acid, and linolenic acid, alkyl benzene sulfonates such as sodium dodecyl benzene sulfonate, higher alcohol sulfate esters, and alkyl sulfosuccinates; cationic emulsifiers such as alkyl trimethyl ammonium chloride, dialkyl ammonium chloride, and benzyl ammonium chloride; and copolymerizable emulsifiers such as sulfo esters of α,β-unsaturated carboxylic acids, sulfate esters of α,β-unsaturated carboxylic acids, and sulfo alkyl aryl ethers. Among them, an anionic emulsifier is suitably used. The emulsifier can be used in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the entire main monomer mixture.

Water can be used as the ion exchange water, and the ion exchange water can be used in an amount of 100 to 400 parts by weight per 100 parts by weight of the main monomer mixture.

The above molecular weight regulator may be, for example, mercaptans such as α-methylstyrene dimer, t-dodecyl mercaptan, n-dodecyl mercaptan, and octyl mercaptan; halogenated hydrocarbons such as carbon tetrachloride, methylene chloride, and methylene bromide; and sulfur-containing compounds such as tetraethyl diuram disulfide, dipentamethylene diuram disulfide, and diisopropyl xanthogen disulfide. The above molecular weight regulator may be used in an amount of 0.01 to 3 parts by weight based on 100 parts by weight of the entire main monomer mixture.

The above activator may be, for example, at least one selected from sodium hydrosulfite, sodium formaldehyde sulfoxylate, sodium ethylenediamine tetraacetate, ferrous sulfate, lactose, dextrose, sodium linolenate, and sodium sulfate. The above activator may be used in an amount of 0.001 to 0.15 parts by weight based on 100 parts by weight of the entire main monomer mixture.

The above redox catalyst may be, for example, sodium formaldehyde sulfoxylate, ferrous sulfate, disodium ethylenediaminetetraacetate, copper sulfate (2), etc. The above redox catalyst may be used in an amount of 0.001 to 0.1 parts by weight based on 100 parts by weight of the total main monomer mixture.

According to the present invention, an acrylic copolymer composition is provided. The acrylic copolymer composition may include an acrylic copolymer obtained as described above and a filler.

The above filler may include at least one selected from the group consisting of carbon black, silica, kaolin clay, talc, and diatomaceous earth.

The amount of the filler used may be 20 to 80 parts by weight, 30 to 65 parts by weight, or 45 to 55 parts by weight, based on 100 parts by weight of the acrylic copolymer, and within this range, excellent workability and mechanical properties are achieved.

Meanwhile, the acrylic copolymer composition according to the present invention may further contain sulfur to enhance the compounding crosslinking effect.

In addition, the acrylic copolymer composition may optionally further include a crosslinking agent and a crosslinking accelerator. The crosslinking agent may be an amine compound, and a specific example is a polyvalent amine compound.

Specific examples of the above polyvalent amine compounds include aliphatic polyvalent amine crosslinking agents, aromatic polyvalent amine crosslinking agents, etc.

Examples of the above aliphatic polyvalent amine crosslinking agents include hexamethylenediamine, hexamethylenediamine carbamate, N,N'-dicinnamylidene-1,6-hexanediamine, and the like.

Examples of the above aromatic polyvalent amine crosslinking agents include 4,4'-methylene dianiline, m-phenylenediamine, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-(m-phenylenediisopropylidene) ziannine, 4,4'-(p-phenylenediisopropylidene) ziannine, 2,2'-bis〔4-(4-aminophenoxy) phenyl〕propane, 4,4'-diaminobenzanilide, 4,4'-bis(4-aminophenoxy) biphenyl, m-xylene diamine, p-xylene diamine, 1,3,5-benzene triamine, 1,3,5-benzene triaminomethyl, and the like.

The amount of the crosslinking agent used may be 0.05 parts by weight to 20 parts by weight, 0.1 parts by weight to 10 parts by weight, or 0.3 parts by weight to 6 parts by weight, based on 100 parts by weight of the acrylic copolymer. Within this range, it is easy to form and maintain a crosslinked product, and excellent elasticity is achieved.

The above cross-linking accelerator may be a cross-linking accelerator that can be used in combination with the above polyhydric amine cross-linking agent, and may have a base dissociation constant in water at 25° C. of 10 to 106, or 12 to 106. As specific examples, the cross-linking accelerator may include a guanidine compound, an imidazole compound, a quaternary onium salt, a tertiary phosphine compound, an alkali metal salt of a weak acid, and the like. Examples of the guanidine compound include 1,3-diphenyl guanidine, di-o-tolyl guanidine, and the like. Examples of the imidazole compound include 2-methylimidazole, 2-phenylimidazole, and the like. Examples of the quaternary onium salt include tetra n-butyl ammonium bromide, octadecyl tri n-butyl ammonium bromide, and the like.

As the above polyvalent tertiary amine compounds, triethylene diamine, 1,8-diaza-bicyclo[5.4.0]undecene-7, etc. can be mentioned. As the tertiary phosphine compounds, triphenyl phosphine, tri p-triylphosphine, etc. can be mentioned. As the alkali metal salt of a weak acid, inorganic weak acid salts such as sodium or potassium phosphate or carbonate, or organic weak acid salts such as stearate or laurate can be mentioned.

The amount of the crosslinking accelerator used may be 0.1 to 20 parts by weight, 0.2 to 15 parts by weight, or 0.3 to 10 parts by weight, based on 100 parts by weight of the acrylic copolymer. Within this range, the crosslinking speed can be appropriately maintained, and the tensile strength of the crosslinked product is excellent.

The acrylic copolymer composition according to the present invention may further contain additives such as a reinforcing agent, an anti-aging agent, a light stabilizer, a plasticizer, a lubricant, an adhesive, a lubricant, a flame retardant, a fungicide, an antistatic agent, a colorant, etc., as needed.

The mixing of the acrylic copolymer composition according to the present invention can be carried out by adopting an appropriate mixing method such as roll mixing, Van Barry mixing, screw mixing, solution mixing, etc., and as a specific example, it can be carried out by a roll mixing method. The mixing order is not particularly limited, but after sufficiently mixing components that are difficult to react or decompose with heat, it is preferable to mix components that are easy to react with heat or are easy to decompose, such as crosslinking agents, at a temperature at which no reaction or decomposition occurs, for a short period of time. The acrylic copolymer composition according to the present invention has the effect of having a low degree of rubber adhesion to the roll and excellent workability when kneaded with a roll.

In addition, the molding method of the acrylic copolymer composition according to the present invention can be performed by compression molding, injection molding, transfer molding, or extrusion molding. In addition, the crosslinking method can be selected depending on the shape of the crosslinked product, and can be performed by a method of performing molding and crosslinking at the same time, a method of performing crosslinking after molding, etc. Since the acrylic copolymer composition of the present invention uses an acrylic copolymer having the above-described configuration, the fluidity of the acrylic copolymer is excellent during molding, the degree of burr generation during molding is low, and the molding precision of the obtained molded product is high.

The acrylic copolymer composition according to the present invention can be manufactured into a cross-linked product by heating, and once the acrylic copolymer of the present invention is cross-linked, it can be formed into a desired shape through a molding or extrusion process, or can be manufactured into a product by curing simultaneously or subsequently.

In addition, the manufactured product can be used as various automobile parts such as rubber for engine mounts, transmission seals, and crankshaft seals.

Hereinafter, the present invention will be described in more detail by way of examples. However, the following examples are intended to illustrate the present invention, and it will be apparent to those skilled in the art that various changes and modifications can be made within the scope and technical idea of the present invention, and the scope of the present invention is not limited to these examples alone.

< Example >

Example 1

<Manufacture of acrylic copolymer rubber>

In a polymerization reactor equipped with a homomixer, a main monomer mixture composed of 27.0 wt% of butyl acrylate, 55.0 wt% of ethyl acrylate, 14.0 wt% of 2-methoxy ethyl acrylate, and 4.0 wt% of vinyl chloro acetate, and 100 parts by weight of the main monomer mixture, 50.0 parts by weight of purified water, 1.0 parts by weight of sodium lauryl sulfate as an emulsifier, 0.005 parts by weight of cumene hydroperoxide as an initiator, 0.1 parts by weight of a mixture of 60 wt% of sodium stearate and 40 wt% of sodium dicarboxylate represented by the following chemical formula 5 as a first crosslinking agent, and 0.025 parts by weight of n-dodecyl mercaptan (trade name: Thiocarcor 20, Kaos Corporation) as a molecular weight regulator were charged and stirred to obtain a monomer emulsion.

Next, 100.0 parts by weight of pure water and 0.005 parts by weight of sodium formaldehyde sulfoxylate were charged into a polymerization reactor equipped with a thermometer and a stirring chamber, stirred for 10 minutes, and the monomer emulsion prepared above was incrementally added in a constant amount over 2 hours. Thereafter, the reaction was continued for 4 hours while maintaining the temperature inside the polymerization reactor at 50°C, and when it was confirmed that the polymerization conversion rate had reached 95%, hydroquinone was added as a polymerization terminator to terminate the polymerization reaction and obtain an emulsified polymer solution.

Thereafter, 70 parts by weight of industrial water and 2.0 parts by weight of calcium chloride were added to the coagulation tank, and the temperature was raised to 85°C while stirring. When the temperature reached 85°C, the polymerized emulsion polymerization solution was continuously added to coagulate the polymer. After performing pure washing three times, the coagulated polymer was dried in a hot air dryer at 110°C for 1 hour, thereby obtaining a solid acrylic copolymer.

[Chemical Formula 5]

<Manufacture of acrylic copolymer composition>

100 parts by weight of the above acrylic copolymer was stirred at 50 rpm at 50°C for 30 seconds using a Haake mixer, then 50 parts by weight of carbon black, 1.0 parts by weight of stearic acid, 2.0 parts by weight of antioxidant, 0.3 parts by weight of sulfur, 0.3 parts by weight of potassium soap, and 2.5 parts by weight of sodium soap were added and mixed at 50°C for 360 seconds, and then an acrylic copolymer composition mixed using a roll mill device was obtained.

Example 2

In the above Example 1, the same procedure as in the above Example 1 was carried out, except that 0.05 weight part of ethoxylated bisphenol A dimethacrylate 10 (Bisphenol A (EO) 10 Dimethacrylate, BPA (EO) 10DMA) was added together with the addition of the first cross-linking agent as the second cross-linking agent.

Example 3

The same method as Example 2 was performed, except that 0.1 part by weight of the second cross-linking agent was added instead of 0.05 part by weight in the above Example 2.

Example 4

In the above Example 2, the same method as Example 2 was performed except that 0.03 part by weight of the second cross-linking agent was added instead of 0.05 part by weight.

Example 5

The same method as Example 2 was performed, except that 0.2 part by weight of the second cross-linking agent was added instead of 0.05 part by weight in the above Example 2.

Example 6

In the above Example 2, the same method as Example 2 was performed except that 0.5 part by weight of the first cross-linking agent was added instead of 0.1 part by weight.

Comparative example 1

In the above Example 2, the same method as Example 2 was performed except that sodium stearate was added as the first cross-linking agent.

Comparative example 2

In the above Example 2, the same method as in the above Example 2 was performed, except that sodium dicarboxylic acid of the above chemical formula 5 was added as the first cross-linking agent.

Comparative example 3

In the above Example 2, the same method as Example 2 was performed except that 0.05 part by weight of the first cross-linking agent was added instead of 0.1 part by weight.

Comparative example 4

In the above Example 2, the same method as Example 2 was performed except that 0.6 part by weight of the first cross-linking agent was added instead of 0.1 part by weight.

< Experimental example >

Experimental example 1

The patterned viscosity, stress relaxation property and extrusion processability of the acrylic copolymer compositions manufactured from the above Examples 1 to 6 and Comparative Examples 1 to 4, and the tensile strength of the test pieces manufactured from the acrylic copolymer compositions were measured by the following methods, and the results are shown in Tables 1 and 2 below.

* Pattern viscosity (ML ₁₊₄ , 100 ℃): The pattern viscosity (polymethylene viscosity) of the acrylic copolymer composition was measured according to JIS K6300.

* Stress relaxation property: The stress relaxation property of the acrylic copolymer composition was confirmed by pattern stress relaxation measurement according to ASTM D1616-7. Specifically, under the measurement conditions of pattern viscosity, when the rotor stops (0 seconds) 4 minutes after the measurement, the torque was set to 100%, and the pattern stress relaxation (the amount of decay of pattern viscosity per unit time) was measured by dividing the amount of decay of pattern viscosity until that value was relaxed by 80% by the time until the relaxation occurred. The smaller the amount of decay of pattern viscosity per unit time, the better.

*Extrusion processability: The extrusion processability of the unvulcanized acrylic copolymer composition was confirmed by a Gabe die extrusion test according to ASTM D2230 A method. Specifically, the unvulcanized acrylic rubber composition was extrusion-molded using an extruder with a Gabe die attached to the tip (single-extrusion barrel diameter 20 mm, rotation speed 30 rpm, barrel temperature 60°C, head temperature 80°C). The smoothness of the surface skin (extrusion skin) of the extrusion-molded acrylic copolymer composition was evaluated on a five-level scale of 1 to 5. The evaluation criterion was set as 5 as good, and 3 or lower as poor.

* Tensile strength: An acrylic copolymer composition was put into a mold measuring 15 cm in length, 15 cm in width, and 20 cm in depth, and pressed at 170°C for 20 minutes while applying a press pressure of 10 MPa to perform primary cross-linking, and then the obtained primary cross-linked product was heated in a gear-type oven at 170°C for 4 hours to perform secondary cross-linking, thereby obtaining a sheet-shaped cross-linked rubber product. The obtained cross-linked rubber product was punched with a No. 3 dumbbell to produce a test piece. Next, the tensile strength (MPa) was measured as a steady-state property (mechanical strength) using this test piece according to JIS K6251. In addition, when the tensile strength was 9.0 MPa or higher, the mechanical strength was considered excellent, and when the tensile strength was less than 9.0, the mechanical strength was considered poor.

division Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Patterned dot
(ML1+4, 100 ℃) 40 38 39 38 39 41 Stress relaxation 0.2< 0.2< 0.2< 0.2< 0.2< 0.2< Tensile strength (TS) 8.5 13.5 12.8 11.8 13.5 12.4 Extrusion processability 3 5 5 3 3 5

division Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Patterned dot
(ML1+4, 100 ℃) 32 43 44 44 Stress relaxation 0.4< 0.3< 0.5< 0.5< Tensile strength (TS) 7.9 8.3 7.5 6.9 Extrusion processability 1 1 2 3

Referring to Table 1 above, it can be confirmed that Examples 2, 3, and 6, in which all components forming the acrylic copolymer according to the present invention are included in an appropriate range of contents, exhibit excellent stress relaxation properties, tensile strength, and extrusion processability. On the other hand, Example 1, which did not include the second cross-linking agent, showed a minimal effect of improving the tensile strength and extrusion processability compared to the other examples, and even when the second cross-linking agent was included, Example 4, in which the content of the second cross-linking agent was included below the appropriate range, and Example 5, in which the content of the second cross-linking agent was included above the appropriate range, still showed a minimal effect of improving the extrusion processability.

Meanwhile, referring to Table 2, it can be confirmed that Comparative Example 1, which does not include sodium dicarboxylic acid as the first cross-linking agent, and Comparative Example 2, which does not include sodium stearate, have significantly lowered extrusion processability, and that the stress relaxation property and tensile strength are also lowered compared to the Examples. In addition, it can be confirmed that Comparative Example 3, in which the content of the first cross-linking agent is below the appropriate range and Comparative Example 4, in which the content of the first cross-linking agent is above the appropriate range, have significantly lowered stress relaxation property, and that the tensile strength and extrusion processability are also lowered compared to the Examples, even when both compounds of the first cross-linking agent are included. Through this, it can be confirmed that the stress relaxation property, tensile strength, and extrusion processability of Comparative Examples 1 to 4 are all inferior to those of the Examples.

Claims (11)

Containing a repeating unit derived from a main monomer and a crosslinking portion derived from a first crosslinking agent,
The above-mentioned repeating unit derived from the main monomer includes a repeating unit derived from a (meth)acrylic acid alkyl ester monomer, a repeating unit derived from a (meth)acrylic acid alkoxy alkyl ester monomer, and a repeating unit derived from a crosslinking monomer.
The above first cross-linking agent comprises a metal salt compound of a saturated fatty acid and a metal salt compound of a dicarboxylic acid,
An acrylic copolymer, wherein the cross-linking portion derived from the first cross-linking agent is included in an amount of 0.1 to 0.5 parts by weight based on 100 parts by weight of the total repeating unit derived from the main monomer. In the first paragraph,
An acrylic copolymer wherein the metal salt compound of the above saturated fatty acid is a compound represented by the following chemical formula 1.
[Chemical Formula 1]

In the above chemical formula 1,
M is sodium or potassium, and n is an integer from 10 to 30. In the first paragraph,
An acrylic copolymer wherein the metal salt compound of the above dicarboxylic acid is a compound represented by the following chemical formula 2.
[Chemical formula 2]

In the above chemical formula 2,
M ₁ and M ₂ are the same or different and each independently an alkali metal,
L ₁ and L ₂ are the same or different, and each independently an alkylene group having 1 to 15 carbon atoms,
X is a cycloalkenylene group having 1 to 20 carbon atoms, substituted with 1 or more alkyl groups having 1 to 10 carbon atoms. In the first paragraph,
An acrylic copolymer wherein the metal salt compound of the above dicarboxylic acid is a compound represented by the following chemical formula 3.
[Chemical Formula 3]


In the above chemical formula 3,
M ₃ and M ₄ are the same or different and each independently an alkali metal. In the first paragraph,
An acrylic copolymer wherein the first cross-linking agent comprises 50 to 80 wt% of a metal salt compound of a saturated fatty acid and 20 to 50 wt% of a metal salt compound of a dicarboxylic acid. In the first paragraph,
The above acrylic copolymer further comprises a crosslinking moiety derived from a second crosslinking agent,
An acrylic copolymer wherein the second cross-linking agent is an ethoxylate bisphenol A di(meth)acrylate containing 2 to 20 ethoxy groups in repeating units. In Article 6,
An acrylic copolymer wherein the second cross-linking agent is ethoxylated bisphenol A dimethacrylate 10 (Bisphenol A (EO)10 Dimethacrylate). In Article 6,
An acrylic copolymer, wherein the cross-linking portion derived from the second cross-linking agent is included in an amount of 0.05 to 0.1 parts by weight based on 100 parts by weight of the total repeating unit derived from the main monomer. In the first paragraph,
An acrylic copolymer, wherein the repeating unit derived from the main monomer comprises 65 to 93 wt% of a repeating unit derived from a (meth)acrylic acid alkyl ester monomer, 5 to 30 wt% of a repeating unit derived from a (meth)acrylic acid alkoxy alkyl ester monomer, and 0.1 to 20 wt% of a repeating unit derived from a crosslinking monomer. A step (S10) of preparing a main monomer mixture comprising a (meth)acrylic acid alkyl ester monomer, a (meth)acrylic acid alkoxy alkyl ester monomer and a crosslinking monomer; and
It includes a step (S20) of adding a first cross-linking agent to the above main monomer mixture and polymerizing it,
The above first cross-linking agent comprises a metal salt compound of a saturated fatty acid and a metal salt compound of a dicarboxylic acid,
A method for producing an acrylic copolymer, wherein the first cross-linking agent is used in an amount of 0.1 to 0.5 parts by weight based on 100 parts by weight of the entire main monomer mixture. An acrylic copolymer composition comprising an acrylic copolymer and a filler according to any one of claims 1 to 9.