JP2000351815A - Crosslinked vinyl polymer, preparation thereof and damping material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crosslinked vinyl polymer which solves the problems concerning the performance required to meet the diverse usage of damping materials and the high performance requirements or those concerning the workability at preparation, which could not be solved with the conventional damping materials, has a large dynamic loss factor, has an excellent damping property and is suitably used as a damping material. SOLUTION: A crosslinked vinyl polymer is prepared by polymerizing a polymerizable composition containing a polyfunctional vinyl compound, a metal salt compound having multiple polymerizable vinyl groups within a molecule and other vinyl compounds (a) which are copolymerizable with these compounds, and has a dynamic loss factor, determined by a dynamic viscoelasticity measurement at 25 deg.C, 10 Hz, of 0.9 or larger. Preferably, the above-mentioned vinyl compounds (a) contain an aromatic vinyl compound such as styrene and/or styrene derivative, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crosslinked vinyl polymer, a method for producing the same, and a vibration damping material containing the crosslinked vinyl polymer.

[0002]

2. Description of the Related Art As one of recent major social problems, there is an environmental problem due to noise and vibration. In addition, due to the great damage caused by recent frequent earthquakes, there is a great interest in vibration control technology. Therefore, in recent years, polymer materials as vibration damping materials have been receiving attention, including their composites.

[0003] A vibration damping material is a material used for suppressing the generation of noise due to vibration and impact and reducing noise and vibration, for example, by attenuating vibration energy due to molecular friction. Such a vibration energy attenuation phenomenon shows different behaviors depending on materials such as metal, glass, concrete, wood, rubber, and plastic. The most damping of these materials are rubber and plastic materials,
In general, vibration control performance is exhibited by converting vibration energy from the outside into heat energy. Such behavior is explained by changes in storage elastic modulus and dynamic loss (tan δ) in dynamic viscoelasticity measurement, and is intermediate between the glass region and rubber elasticity behavior in the viscoelasticity behavior of the polymer material, that is,
In the glass transition region, the viscoelastic region (Vis
(coelasticity), which means that the heat generated by friction between molecules is the largest.

[0004] Therefore, as a high damping damping material, a damping material having a large dynamic loss is required. Examples of the vibration damping material having such high damping characteristics include, for example, an oil-impregnated material such as norbornene rubber, a gel body such as silicone gel, a sponge structure, or a composite rubber containing a vibration damping filler or the like. (“7th Polymer-Based Vibration Suppressing Material, Characteristics and Vibration / Noise Prevention Measures for Polymer-Based Vibration Suppressing Materials-Highly Functional Product Development and Application Examples”, pp. 1-2 to 1-5, Jan. 1998)
(Publication of Technical Association for Plastic Technology, February 8, 2007).

[0005]

However, these conventional vibration damping materials are not pure crosslinked polymers, and are inferior in various material properties such as tensile strength, tensile elongation, and compression set. There is a problem that creep increases. In addition, these conventionally known vibration damping materials are:
There is a problem in ease of use such as compounding as a vibration damping material and moldability, and there is a restriction on use.

[0006] Accordingly, it is very important to provide a vibration damping material having a large dynamic loss and excellent in these material properties, especially a vibration damping material composed of a pure crosslinked polymer in expanding the range of application. Play a role.

As a crosslinked polymer having excellent material properties, the applicant of the present invention has excellent physical properties such as heat resistance, oil resistance, weather resistance and the like, and has a sealing material in application fields such as automobiles, civil engineering construction, ships and the like. (Meth) acrylic cross-linked elastomer using polyfunctional vinyl monomer and metal salt as cross-linkable monomer in order to improve the mechanical strength of acrylic rubber, which is suitably used as rubber and packing material and hose material (JP-A-10-245421 and JP-A-10-245422). The (meth) acrylic crosslinked elastomer is a highly practical crosslinked rubber having excellent tensile strength, tensile elongation and compression set.

However, in the above publication, no particular consideration is given to the damping properties, and the resulting crosslinked polymer still does not have satisfactory performance as a damping material. Therefore, in order to improve the vibration damping properties of the crosslinked polymer, that is, the above (meth) acrylic crosslinked elastomer, for example, when applying a conventional compounding technique or the like,
As a result, the strength / elongation characteristics of the material, that is, the tensile strength and the tensile elongation are reduced, or the compression set is increased. For this reason, it is difficult to satisfy both the vibration damping property and the various material properties described above, in particular, both the vibration damping property and the strength.
The improvement of the vibration damping property causes a defect in the material performance such as a high creep property, a decrease in rubber elasticity, and a decrease in heat resistance.

The present invention has been made in view of the above-mentioned conventional problems, and has as its object to diversify the applications of vibration damping materials.
There is no problem of performance of the above conventional vibration damping material and the problem of workability at the time of manufacturing against sophistication of required performance, large dynamic loss, excellent vibration damping property, suitable for use as a vibration damping material It is an object of the present invention to provide a vinyl-based crosslinked polymer which can be produced, a simple production method thereof and a vibration damping material.

[0010]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, the dynamic loss in dynamic viscoelasticity measurement is as large as 0.9 or more, which is suitable for a vibration damping material. Thus, the present invention was completed by successfully obtaining a vinyl-based crosslinked polymer which does not cause the above-mentioned conventional problems.

That is, in order to solve the above-mentioned problems, a vinyl-based crosslinked polymer according to the present invention comprises a polyfunctional vinyl compound, a metal salt compound having a plurality of polymerizable vinyl groups in a molecule, A polymerizable composition containing these compounds and another copolymerizable vinyl compound (a) is polymerized,
It is characterized in that the dynamic loss in dynamic viscoelasticity measurement at 10 ° C. and 10 Hz is 0.9 or more.

According to a second aspect of the present invention, there is provided a vinyl cross-linked polymer according to the first aspect, wherein the vinyl cross-linked polymer according to the first aspect has a tensile strength at 25 ° C. of 5%.
The tensile elongation at 0 kgf / cm ² or more and / or 25 ° C. is 300% or more.

In order to solve the above-mentioned problems, the vinyl-based crosslinked polymer according to the third aspect of the present invention is a polymer according to the first or second aspect, which has a compression ratio of 25% at 90 ° C.
It is characterized in that the compression set after compression for 0 hours is 50% or less.

According to a fourth aspect of the present invention, there is provided a vinyl crosslinked polymer according to any one of the first to third aspects, wherein the vinyl compound ( a) is characterized in that it contains an aromatic vinyl compound.

According to a fifth aspect of the present invention, there is provided a vinyl crosslinked polymer according to the fourth aspect of the present invention, wherein the polymerizable composition is a polyfunctional vinyl compound 0. 0.1% to 30% by weight, 0.1% to 30% by weight of a metal salt compound and 5% by weight of an aromatic vinyl compound 5
% By weight to 60% by weight.

The above vinyl cross-linked polymer is heated at 25 ° C., 10
It realizes a high dynamic loss of 0.9 or more in dynamic viscoelasticity measurement at Hz, and has excellent vibration damping properties. The vinyl-based crosslinked polymer has a tensile strength and a tensile elongation, because the polymerizable composition uses a polyfunctional vinyl compound and a metal salt compound having a plurality of polymerizable vinyl groups in a molecule in combination. Excellent in various material properties such as strength / elongation characteristics and compression set, etc., can realize low creep, and also has excellent heat resistance, diversifying applications of vibration damping materials and improving required performance. There is no risk of causing a problem in performance and a problem in workability at the time of manufacturing as seen in the conventional damping material, and the polymer can be suitably used as a damping material polymer as a damping material polymer. The vinyl-based crosslinked polymer has, for example, excellent material properties as described in claim 2 or 3. Therefore, according to the present invention, the vibration damping property and the various material properties described above, preferably 25
Tensile strength at 50 ° C is 50 kgf / cm ² or more, 25 ° C
At a tensile elongation of 300% or more and a compressibility of 25%
Compression set at 70 ° C. for 70 hours
%, And more preferably at least one, more preferably two, and most preferably three of the physical properties of the vinyl-based crosslinked polymer can be provided. As described above, the vinyl-based crosslinked polymer has an excellent balance between the damping properties and the material properties such as tensile strength, tensile elongation, and compression set, and can be used as it is as a damping material. Therefore, according to the present invention, it is possible to provide a vibration damping material which is made of a pure crosslinked polymer and can be suitably used in various fields of application. For this reason, according to the above configuration, there is no restriction on use, and there is no problem in terms of ease of use such as compounding as a vibration damping material and moldability. In addition, by blending, as the vinyl compound (a), an aromatic vinyl compound such as styrene and / or a styrene derivative into the polymerizable composition, a vinyl compound exhibiting high vibration damping properties in a wide temperature range can be obtained. A crosslinked polymer can be obtained.

In order to solve the above-mentioned problems, the method for producing a vinyl-based crosslinked polymer according to the present invention has the following features.
A method for producing a vinyl-based crosslinked polymer according to the above, comprising reacting a metal compound with an unsaturated acid in the presence of a polyfunctional vinyl compound and / or a vinyl compound (a) to form a plurality of vinyl groups in the molecule. After obtaining a mixture containing a metal salt compound having the following formula, without isolating a metal salt compound having a plurality of vinyl groups in the molecule from the resulting mixture, finally, the polyfunctional vinyl compound and a molecule A polymerizable composition containing a metal salt compound having a plurality of polymerizable vinyl groups therein and the vinyl compound (a) is prepared and polymerized.

According to the above method, the vinyl cross-linked polymer according to claim 1 can be produced in a simple process with good productivity, good workability, and at low cost.

The polymerizable composition used in the present invention has a low viscosity and is easy to handle. For this reason, it is possible to extremely easily perform mixing, casting, impregnation, lamination, coating, etc. of molding, processing, and construction work of auxiliary materials such as fillers, and ordinary temperature curing, heat curing, light irradiation, and the like. By polymerizing by the method, a polymer can be quickly obtained. According to the above method, the polymerizable composition, by various conventionally known polymerization methods, for example, by bulk polymerization, emulsion polymerization, suspension polymerization, dispersion polymerization and the like, by polymerizing various forms For example, as elastomers, films, particles, emulsions, etc., automobiles,
In a wide range of fields such as OA equipment, electrical and electronic equipment, and construction,
For example, it is possible to obtain a vinyl-based crosslinked polymer that can be used in applications such as a damping rubber and a damping paint.

According to a seventh aspect of the present invention, there is provided a vibration-damping material comprising the vinyl cross-linked polymer according to any one of the first to fifth aspects, in order to solve the above-mentioned problems.

According to the above-mentioned structure, the vinyl-based cross-linked polymer can be used in various applications of the vibration damping material and the performance problems of the conventional vibration damping material against the sophistication of required performance, and the workability at the time of production. Vibration-damping material containing the above-mentioned vinyl-based cross-linked polymer because it can satisfy both the vibration-damping properties and the material properties such as tensile strength, tensile elongation and compression set Also, there are no problems with the performance of conventional damping materials and workability during manufacturing due to the diversification of applications of the damping materials and sophistication of required performance, large dynamic loss, vibration damping characteristics And material properties such as tensile strength, tensile elongation and compression set. Further, as described above, the vinyl-based crosslinked polymer has an excellent balance between vibration damping properties and material properties such as tensile strength, tensile elongation, and compression set. Therefore, the vinyl cross-linked polymer according to the present invention may be used as it is as a vibration damping material, or may be used as a composite. When the vinyl-based crosslinked polymer is directly used as the vibration-damping material, a vibration-damping material consisting of a pure crosslinked polymer and suitably usable in various fields of application can be provided.

Hereinafter, the present invention will be described in detail. The vinyl cross-linked polymer according to the present invention, a polyfunctional vinyl compound,
It is obtained by polymerizing a polymerizable composition containing a metal salt compound having a plurality of polymerizable vinyl groups in a molecule and another vinyl compound (a) copolymerizable with these compounds.
Dynamic loss in dynamic viscoelasticity measurement at 10 Hz (hereinafter referred to as
tan δ) is 0.9 or more, preferably 1.0 or more, more preferably 1.1 or more.

The vinyl-based crosslinked polymer is a polymer having an excellent balance between material properties such as tensile strength, tensile elongation and compression set and vibration damping properties. , (1) to (3), the following physical properties, ie, (1) the tensile strength at 25 ° C. is preferably 50 kg
f / cm ² or more, more preferably 65 kgf / cm ² or more, particularly preferably 69 kgf / cm ² or more, (2) 25
C. is preferably 300% or more, more preferably 450% or more, particularly preferably 700% or more,
(3) At least one of compression set of preferably 50% or less, more preferably 32% or less, particularly preferably 26% or less, preferably 2%, when compressed at 90 ° C. for 70 hours at a compression ratio of 25%. And more preferably (1) to
While satisfying all the physical properties represented by (3), as described above, (4) tan δ in dynamic viscoelasticity measurement at 25 ° C. and 10 Hz is 0.9 or more, preferably 1.0 or more, more preferably Satisfies the condition of 1.1 or more.

The above-mentioned physical properties (1) to (3) are the most basic physical properties required as a crosslinked rubber, and their numerical levels are quite high. In particular, the numerical value that the tensile product expressed by the product of the tensile elongation and the tensile strength is 15,000 (kgf ·% / cm ² ; tensile elongation × tensile strength = 50 × 300 = 15,000) is a high level. Also, the value of the compression set at 50% or less when compressed at 90 ° C. for 70 hours at a compression ratio of 25% is a high level. Therefore, the vinyl-based crosslinked polymer according to the present invention is excellent in the above various material properties and vibration damping properties, and as a polymer for a vibration damping material having a good balance between both.
It can be particularly suitably used for various applications and fields where vibration damping is required.

The vinyl-based crosslinked polymer is, for example, a polyfunctional vinyl compound and / or another vinyl compound copolymerizable with the polyfunctional vinyl compound and / or a metal salt compound having a plurality of polymerizable vinyl groups in a molecule. (A) in the presence of at least one component selected from the group consisting of: reacting a metal compound, preferably a polyvalent metal (hydroxide) with an unsaturated acid to form a plurality of vinyl groups in the molecule. After obtaining a mixture containing a metal salt compound having, without isolating the metal salt compound from the obtained mixture, finally, a polyfunctional vinyl compound and a metal salt having a plurality of polymerizable vinyl groups in the molecule It is easily produced by preparing and polymerizing a polymerizable composition containing the compound and the vinyl compound (a).

Among the components constituting the polymerizable composition used in the present invention, a polyfunctional vinyl compound is a compound having two or more polymerizable vinyl groups in a molecule, and is generally called a polyfunctional vinyl monomer. In addition to the low molecular weight compounds
As described below, polymers having higher molecular weights are also included.

Among the above polyfunctional vinyl compounds, examples of the low molecular weight compound referred to as a so-called polyfunctional vinyl monomer include, for example, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, and ethylene glycol. Bifunctional vinyl compounds such as di (meth) acrylate of diphthalate, di (meth) acrylate of diethylene glycol diphthalate, divinylbenzene, diglycidyl (meth) acrylate of dimer acid, diethylene glycol divinyl ether, and triethylene glycol divinyl ether; Trifunctional vinyl compounds such as trimethylolpropane tri (meth) acrylate; and the like, but are not particularly limited. One of these compounds may be used alone, or two or more of them may be used in combination as appropriate.

Among the above polyfunctional vinyl compounds, polymers,
That is, the polymer having two or more polymerizable vinyl groups in the molecule (hereinafter referred to as a vinyl group-containing polymer) is not particularly limited, but is preferably a polymer excluding the vinyl group-containing polymer. Dissolved in the polymerizable composition according to the invention,
In addition, any polymer may be used as long as it is a polymer that can be copolymerized with the components contained in the polymerizable composition. More specifically, as the vinyl group-containing polymer, a polymer having a number average molecular weight (Mn) of 500 or more and having two or more vinyl groups involved in a polymerization reaction in a side chain and / or a terminal. Should be fine. The method for synthesizing the vinyl group-containing polymer is not particularly limited. Examples of the vinyl group-containing polymer include a (meth) acrylate polymer, a polyvinyl ester, and an unsaturated polyester.

As the above (meth) acrylate-based polymer, for example, a mixture of a vinyl compound containing an alkyl (meth) acrylate as a main component is prepared by solution polymerization, bulk polymerization, suspension polymerization, emulsion polymerization. The polymer obtained after vinyl polymerization by a known method such as
), But are not particularly limited, compounds synthesized by introducing a vinyl group.
As the vinyl compound other than the alkyl (meth) acrylate in the above mixture, specifically, for example,
Examples thereof include (meth) acrylic acid, acrylonitrile, and maleimides, but are not particularly limited.

As a method for introducing a vinyl group into the polymer (A), specifically, for example, when the polymer (A) has a carboxyl group, the polymer (A)
A method of reacting glycidyl (meth) acrylate with a polymer; when the polymer (A) has a hydroxyl group, reacting the polymer (A) with a polyfunctional isocyanate such as toluene diisocyanate; A method of reacting a hydroxyl group-containing vinyl monomer such as hydroxyethyl (meth) acrylate with the reaction product; and the like. In the above method, a catalyst, a polymerization inhibitor and the like can be used as necessary.

Further, for example, a polymer syrup (that is, a polymer (A), which is obtained by bulk polymerization of a mixture of vinyl compounds containing alkyl (meth) acrylate as a main component and interrupting the polymerization reaction, By introducing a vinyl group into an unreacted mixture containing an unreacted alkyl (meth) acrylate), a (meth) acryl syrup containing a (meth) acrylate polymer can also be obtained.

Examples of the polyvinyl ester include known polyvinyl esters such as an epoxy vinyl ester, a urethane vinyl ester, and a polyester vinyl ester, but are not particularly limited. Epoxy vinyl esters are compounds obtained by reacting (meth) acrylic acid with an epoxy resin. Specific examples of the epoxy resin include glycidyl ethers of bisphenols and novolak phenols. Urethane vinyl esters are
A compound obtained by reacting a hydroxyalkyl (meth) acrylate with a polyisocyanate compound.
Specific examples of the polyisocyanate compound include toluene diisocyanate and xylylene diisocyanate. Examples of the polyester-based vinyl ester include, for example, a compound obtained by reacting a glycidyl ester of (meth) acrylic acid with an oligoester having a carboxyl group at both terminals, and a compound obtained by reacting an oligoester having a hydroxyl group at both terminals with (meth) acrylic acid. And the like.

Examples of the unsaturated polyester include, but are not limited to, known compounds obtained by condensing an acid component and an alcohol component. The reaction conditions for the condensation reaction are not particularly limited. As the acid component, specifically,
For example, saturated polybasic acids and their anhydrides such as phthalic acid, phthalic anhydride, isophthalic acid and adipic acid; unsaturated polybasic acids and their anhydrides such as maleic acid and fumaric acid;
And the like. Specific examples of the alcohol component include bifunctional alcohols such as ethylene glycol and propylene glycol; trifunctional alcohols such as trimethylolpropane; and monoepoxides such as ethylene oxide and propylene oxide. The unsaturated polyester may be modified with various compounds such as a diene compound such as dicyclopentadiene; a rubber component such as a butadiene-acrylonitrile copolymer having a functional group at a terminal;

Further, among the components constituting the polymerizable composition according to the present invention, a metal salt compound having a plurality of polymerizable vinyl groups in the molecule (metal salt-containing vinyl monomer) is
It is a reaction product (salt) of a metal compound and an unsaturated acid. Examples of the metal compound according to the present invention include inorganic metal compounds such as metal oxides, metal hydroxides, metal chlorides and metal carbonates; metal carboxylate salts such as metal acetate salts; complexes such as acetylacetone complexes; Organometallic compounds such as metal alcoholates such as propylate and metal butyrate; but are not particularly limited. These compounds may be used alone or in combination of two or more. The above-mentioned metal may be a monovalent metal or a polyvalent metal.

Of these metal compounds, metal oxides and metal hydroxides are more preferred, and polyvalent metal oxides and hydroxides are more preferred. Specific examples of the polyvalent metal oxide include zinc oxide (zinc white) and magnesium oxide, but are not particularly limited. As the polyvalent metal hydroxide, specifically,
For example, zinc hydroxide, magnesium hydroxide, aluminum hydroxide, calcium hydroxide and the like can be mentioned, but it is not particularly limited. By using the above-mentioned polyvalent metal oxide or polyvalent metal hydroxide, physical properties such as mechanical strength of the finally obtained vinyl-based crosslinked polymer are further improved.

The unsaturated acid according to the present invention is not particularly limited as long as it is an unsaturated acid which reacts with a metal compound to form the metal salt compound. The unsaturated acid is
For example, a vinyl monomer used as the vinyl compound (a) may be used. Specific examples of the unsaturated acid include α, β-ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, and cinnamic acid; 2-acryloyloxyethylphthalic acid, 2-methacryloyl Unsaturated carboxylic acids having an ester group such as oxyethyl phthalic acid, 2-methacryloyloxyethyl trimellitic acid and 2-methacryloyloxyethyl pyromellitic acid; unsaturated dicarboxylic acids such as maleic acid, fumaric acid and itaconic acid; Monoesters of unsaturated dicarboxylic acids and monohydric alcohols such as acid monomethyl esters; unsaturated phosphate esters such as 2-methacryloyloxyethyl acid phosphate; and the like. One of these compounds may be used alone, or two or more of them may be used in combination.

The above-mentioned metal salt compound according to the present invention comprises the above-mentioned metal compound and unsaturated acid in the polymerizable composition according to the present invention in a component other than the above-mentioned metal salt compound, ie,
A polyfunctional vinyl compound, and the polyfunctional vinyl compound and / or
Alternatively, at least one component selected from the group consisting of a metal salt compound having a plurality of polymerizable vinyl groups in the molecule and another vinyl compound (a) copolymerizable, more specifically, a vinyl compound (a) Can be easily obtained by reacting in the presence of one or more components (hereinafter, referred to as selected components) such as an aromatic vinyl compound and other vinyl compounds described below. Here, the selected component refers to a part or all of the components obtained by removing the metal salt compound from the finally formed polymerizable composition. in this case,
The produced metal salt compound can be used as it is as a component of the polymerizable composition without isolation.

The equivalent ratio between the unsaturated acid and the metal compound (unsaturated acid / metal compound) depends on the type of unsaturated acid or metal compound used, the combination of both, and the finally obtained vinyl cross-linked polymer. What is necessary is just to set according to the use and various required physical properties, etc., and is not particularly limited,
The range of 1.0 to 1.2 is more preferable.

The method of reacting the metal compound with the unsaturated acid in the presence of the selected component is not particularly limited, but specifically, for example, the reaction of the metal compound with the unsaturated acid in the selected component A method of mixing and stirring at room temperature or under heating may be mentioned. As a result, the reaction proceeds, a metal salt compound is formed, and a mixture in which the metal salt compound is dissolved in the selected component is obtained.

Whether or not the reaction between the metal compound and the unsaturated acid is completed is determined, for example, by determining whether the metal compound used is the selected component and / or
Alternatively, when it is insoluble in the obtained mixture, it may be confirmed by checking whether the obtained mixture is uniform and transparent at normal temperature. The point at which a homogeneous and transparent mixture is obtained at room temperature is the end point of the reaction. Therefore, the operation such as stirring may be terminated at the above time. The reaction conditions such as the reaction temperature and the reaction time are not particularly limited as long as the reaction proceeds and the selected components and the obtained mixture do not deteriorate.

In the above reaction, if necessary, water may be added to the reaction system. That is, the metal compound and the unsaturated acid may be reacted in the presence of the selected component and water. By performing the above reaction in the presence of water, the reaction can proceed more quickly and smoothly, and the solubility of the obtained metal salt compound in the selected component can be further improved. Although the amount of water to be added is not particularly limited, it is more preferable to set the amount to be 4.0 mol or less per 1 mol of the metal compound. Although the detailed reason why the above effects are exhibited by adding water is not clear, it is presumed that water is coordinated with the obtained metal salt compound so that the metal salt compound is solubilized. .

According to the above-described reaction method, the metal salt compound is obtained in a state of being dissolved in the selected component, so that the concentration of the metal salt compound in the obtained mixture can be easily made relatively high. That is, since the concentration of the metal salt compound in the finally formed polymerizable composition can be relatively high, the degree of ionic crosslinking of the finally obtained vinyl-based crosslinked polymer is sufficiently increased. be able to. Therefore, the mechanical strength, elongation, and the like are improved, and a vinyl-based crosslinked polymer having excellent toughness can be produced. Therefore, a polymer for a vibration damping material having excellent toughness can be produced.

If necessary, a polyfunctional vinyl compound or a vinyl compound (a) described below is mixed with the above mixture so that a desired polymerizable composition is finally formed. That is, these components are appropriately mixed with the above mixture so that the ratio (composition ratio) of each component in the polymerizable composition becomes a desired ratio (composition ratio).

As described above, without isolating a metal salt compound having a plurality of vinyl groups in a molecule from the obtained mixture, a required amount of a polyfunctional vinyl compound or vinyl compound (a) can be mixed in the mixture. By doing so, the polymerizable composition according to the present invention, that is, the polymerizable composition for a vibration damping material that can be suitably used for producing a vibration damping material is formed.
In the polymerizable composition, the unsaturated acid (unsaturated monomer having a carboxyl group) used in the production of the metal salt compound may adversely affect the polymerizability of the polymerizable composition of the present invention and its physical properties. It may be included in the range not given.

Further, the polymerizable composition according to the present invention is obtained by synthesizing a metal salt compound having a plurality of vinyl groups in a molecule in a different reaction system from the above polyfunctional vinyl compound and the below-described vinyl compound (a). Thereafter, the metal salt compound can also be produced by adding the metal salt compound to a polymerizable composition comprising other components excluding the polyfunctional vinyl compound from the polymerizable composition.

Among the components constituting the polymerizable composition according to the present invention, the other vinyl compound (a) copolymerizable with the polyfunctional vinyl compound and / or the metal salt compound includes the polyfunctional vinyl compound And / or a vinyl compound that can be copolymerized with a metal salt compound and can realize the above-mentioned tan δ.

The vinyl compound (a) is preferably a compound having one vinyl group and one or more phenyl groups in the molecule, specifically, an aromatic vinyl compound. As the aromatic vinyl compound, more specifically, styrene; styrene derivatives such as p-methylstyrene, pn-butylstyrene, pt-butylstyrene, α-methylstyrene; vinylnaphthalene, alkyl-substituted Vinyl naphthalenes such as vinyl naphthalene; vinyl anthracenes such as vinyl anthracene and alkyl-substituted vinyl anthracene; vinyl carbazoles such as vinyl carbazole and alkyl group-substituted vinyl carbazole; and the like, and these aromatic vinyl compounds are essential. Is the t in the dynamic viscoelasticity measurement at 25 ° C. and 10 Hz.
has an δ of 0.9 or more, and has an excellent balance between damping properties and material properties such as tensile strength, tensile elongation, and compression set, and can be suitably used as a damping material polymer as a damping material polymer. It is preferable for obtaining a system crosslinked polymer.

One of these vinyl compounds (a) may be used alone, or two or more of them may be used as a mixture. Among these vinyl compounds (a), styrene and / or styrene derivatives are preferable because they are easily available and have the excellent physical properties described in (1) to (4).

According to the present invention, for example, the aromatic vinyl compound, preferably styrene and / or styrene derivative, is in the range of 5% to 60% by weight, preferably 15% by weight.
% By weight, more preferably in the range of 20% to 50% by weight, and the polyfunctional vinyl compound in the range of 0.1% to 30% by weight, preferably 2% by weight. 20% by weight, and the metal salt compound is 0.1% by weight.
% To 30% by weight, preferably 2% to 1% by weight.
5% by weight, and if necessary, a polymerizable composition containing the other vinyl compound (a) in the range of 0 to 94.8% by weight (however, the total of these is 100% by weight). %), The dynamic loss in dynamic viscoelasticity measurement at 25 ° C. and 10 Hz is 0.9 or more, and has excellent vibration damping properties over a wide range of temperatures, as well as tensile strength and tensile strength. Excellent material properties such as elongation and compression set
A vinyl-based crosslinked polymer satisfying the physical properties of (1) to (4) and having an excellent balance between these material properties and vibration damping properties can be obtained.

In particular, a damping material using a polymer material generates a large amount of heat due to friction between molecules in a viscoelastic region in the viscoelastic behavior of the polymer material, and exhibits damping characteristics. In selecting the material, it is important how the second-order transition point of the polymer material and the practical temperature range are adjusted. However, the vinyl-based crosslinked polymer according to the present invention obtained by polymerizing the above polymerizable composition is important. Is, as shown in Examples described later, a tan δ value at which the vibration damping property is exhibited can be continuously obtained in a wide temperature range in a practical temperature range of −20 ° C. to 100 ° C. It exhibits excellent vibration control characteristics. Further, the polymerizable composition is excellent in stability, does not precipitate the metal salt compound even when left for a long time, and does not cause the polymerizable composition to increase in viscosity or gel.

When the proportion of the aromatic vinyl compound in the polymerizable composition is less than 5% by weight, the obtained vinyl-based crosslinked polymer, that is, the polymer for a vibration damping material, has reduced vibration damping properties. Specifically, tan δ in a practical temperature range decreases. On the other hand, the ratio of the aromatic vinyl compound is 60% by weight.
When the viscosity exceeds the range, the toughness of the obtained vinyl-based crosslinked polymer is reduced, and a vinyl-based crosslinked polymer which is excellent in balance between material properties and vibration damping properties and can be suitably used as a polymer for vibration damping materials is obtained. This is not preferable because it may not be possible to do so. In addition, the aromatic vinyl compound, particularly, styrene and / or a styrene derivative is added in an amount of 15% by weight to 60%.
When used in the range of% by weight, a high tan δ of 1.0 or more is used.
Can be realized, and both the above-mentioned material properties and vibration damping properties can be satisfied, and a vinyl-based crosslinked polymer suitable as a polymer for a vibration damping material can be obtained.

In general, a material having the largest tan δ is a polymer material. When only tan δ is considered, the tan δ in dynamic viscoelasticity measurement at 25 ° C. and 10 Hz is 0.01 to 1 0.0. Therefore, 1.
Realizing a high tan δ of 0 or more, in particular, exceeds a kind of hurdle that has been difficult to overcome conventionally as a vibration damping material made of a pure crosslinked polymer, and has a very significant meaning. Conventionally, in order to realize a high tan δ, in the field of vibration damping materials, oil impregnated type materials, gel bodies such as silicone gels, sponge structures, or composite rubbers compounded with a vibration damping filler or the like are used. A purely crosslinked polymer, not a purely cross-linked polymer, has been approached with a focus on compounding, and has excellent balance between vibration damping properties and various material properties such as tensile strength, tensile elongation, and compression set. Is not known, and
Due to the problem that the field is limited, a pure crosslinked polymer has a tan δ value of 0.9 or more, preferably 1.0 or more, more preferably 1.1 or more, and
Providing a vibration damping material that satisfies the physical properties (1) to (3) has a very significant meaning in expanding the use applications and fields of the vibration damping material.

In the polymerizable composition having the above composition, if the proportion of the polyfunctional vinyl compound is less than 0.1% by weight, the resulting vinyl crosslinked polymer has a permanent compression set, an elongation (tensile elongation) and the like. Is undesirably increased, resulting in poor rubber elasticity. On the other hand, when the proportion of the polyfunctional vinyl compound exceeds 30% by weight, the mechanical strength and elongation of the obtained vinyl-based crosslinked polymer are reduced to deteriorate toughness, and tan δ is reduced in a wide temperature range, It is not preferable because the vibration damping property is reduced. The use of the above polyfunctional vinyl compound in the range of 2% by weight to 20% by weight can reduce the permanent compression set of the vinyl cross-linked polymer by 32% when compressed at 90 ° C. for 70 hours at a compressibility of 25%.
It works particularly effectively in suppressing the following.

If the proportion of the metal salt compound in the polymerizable composition is less than 0.15% by weight, the mechanical strength, elongation and heat resistance of the resulting vinyl crosslinked polymer are undesirably reduced. On the other hand, the ratio of the metal salt compound is 30% by weight.
If it exceeds, the resulting vinyl-based crosslinked polymer will undesirably increase creep or decrease tan δ over a wide temperature range, resulting in reduced vibration damping.

The above aromatic vinyl compound which can be used when the above polymerizable composition contains a vinyl compound (a) other than the above aromatic vinyl compound, polyfunctional vinyl compound and metal salt compound. The compound, the polyfunctional vinyl compound, and the vinyl compound (a) other than the metal salt compound include the compounds constituting these polymerizable compositions, that is, the aromatic vinyl compound, the polyfunctional vinyl compound, the metal salt compound, and the like. Any copolymerizable vinyl monomer may be used.

Thus, specific examples of the vinyl monomer which can be used as the vinyl compound (a) of the present invention include α, β-ethylenic acid such as acrylic acid, methacrylic acid, crotonic acid, and cinnamic acid. Unsaturated carboxylic acids having an ester group, such as 2-acryloyloxyethyl phthalic acid, 2-methacryloyloxyethyl phthalic acid, 2-methacryloyloxyethyl trimellitic acid, and 2-methacryloyloxyethyl pyromellitic acid; Unsaturated dicarboxylic acids such as maleic acid, fumaric acid and itaconic acid; monoesters of unsaturated dicarboxylic acids and monohydric alcohols such as monomethyl maleate; unsaturated phosphorus containing vinyl groups such as 2-methacryloyloxyethyl acid phosphate Acid ester; methyl acrylate, acrylic acid Alkyl acrylates such as ethyl, n-butyl acrylate, and 2-ethylhexyl acrylate; methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, and methacrylic acid-2-
Alkyl methacrylates such as ethylhexyl; methoxyethyl acrylate, ethoxyethyl acrylate,
Alkoxyalkyl esters of acrylic acid such as butoxyethyl acrylate; alkoxyalkyl esters of methacrylic acid such as methoxyethyl methacrylate, ethoxyethyl methacrylate and butoxyethyl methacrylate; vinyl compounds containing epoxy groups such as glycidyl (meth) acrylate and allyl glycidyl ether A halogen-containing vinyl compound such as vinyl chloroacetate, allyl chloroacetate and vinylbenzyl chloride; 2-hydroxyethyl (meth) acrylate, 2- (meth) acrylate
Hydroxyl-containing vinyl compounds such as hydroxypropyl and ethylene glycol monoallyl ether; acrylamide;
Amide group-containing vinyl compounds such as methacrylamide; amino group-containing vinyl compounds such as dimethylaminoethyl (meth) acrylate; silyl group-containing vinyl compounds such as vinylmethoxysilane and vinylethoxysilane; maleimides such as cyclohexylmaleimide and phenylmaleimide Vinyl compounds containing nitrile groups such as acrylonitrile and methacrylonitrile; alicyclic vinyl compounds such as dicyclopentadiene and ethylidene norbornene; vinyl carboxylate esters such as vinyl acetate and vinyl propionate; olefin compounds such as chloroprene, isoprene and butadiene. Alkyl vinyl ether compounds such as n-butyl vinyl ether, sec-butyl vinyl ether, t-butyl vinyl ether, ethyl vinyl ether and 2-ethylhexyl vinyl ether And the like, but are not particularly limited. One of these compounds may be used, if necessary, or two or more of them may be used.

Among the above vinyl monomers, the use of an alkyl (meth) acrylate or an alkoxyalkyl (meth) acrylate in combination with the aromatic vinyl compound as another vinyl compound (a) of the present invention is as follows. It is preferable to maintain the above-mentioned balance of the physical properties of the obtained vinyl cross-linked polymer (cured product).

The unsaturated acid used in the production of the acrylic syrup containing a carboxyl group among the acrylic syrups exemplified as the polyfunctional vinyl compound of the present invention is present in the acrylic syrup. In some cases, there is no problem even if it is used as another vinyl compound (a) that can be used as a part of the polymerizable composition of the present application.

Accordingly, the polymerizable composition of the present invention may be optionally used as another vinyl compound (a) as long as the polymerizable composition of the present invention and the physical properties thereof are not adversely affected. A carboxyl group-containing monomer that is an unsaturated acid can be included. The use of the above unsaturated acid as the other vinyl compound (a) means that after the formation of the polymer, the unsaturated acid forms an ionic crosslink with the structure derived from the metal salt compound. This is a preferred embodiment in the present invention because the characteristics (strength and the like) of the elastomer are improved. The amount of the unsaturated acid used at this time is not particularly limited. The amount of the unsaturated acid in the polymerizable composition of the present invention, for example, after synthesizing an acrylic syrup or a metal salt compound having a plurality of polymerizable vinyl groups in the molecule, which can be used in the above polyfunctional vinyl compound, It is preferably 20% by weight or less based on the polymerizable composition.
It is more preferably at most 5% by weight, more preferably at most 5% by weight.

Further, a synthetic resin which is dissolved or dispersed in the polymerizable composition may be added to the polymerizable composition as required. By adding a synthetic resin to the polymerizable composition, the solubility and dispersion stability of the metal salt compound in the polymerizable composition can be further improved, and if necessary, the polymerizable composition may be added to the polymerizable composition. The dispersion stability of various additives (described later) to be added can be further improved. In addition, since the polymerizable composition can be given an appropriate viscosity, the handleability, moldability, workability, productivity, and the like of the polymerizable composition can be further improved.

The above synthetic resin is dissolved or dispersed in the polymerizable composition, and impairs the performance (various physical properties) that the vinyl-based crosslinked polymer of the present invention obtained by polymerizing the polymerizable composition should have. Any synthetic resin may be used, and there is no particular limitation. Also, the amount of synthetic resin added is
There is no particular limitation. When a synthetic resin is added to the polymerizable composition, the polymerizable composition is polymerized in the presence of the synthetic resin.

Specific examples of the synthetic resin include acrylic resins such as polyalkyl (meth) acrylate resins and acrylic rubbers; polyolefin resins such as polyethylene resins, polypropylene resins and diene polymers; polyester resins. Known synthetic resins such as epoxy resin; polystyrene resin; These synthetic resins may be used alone if necessary,
Two or more of them may be used by appropriately mixing. Among them, acrylic resin is more preferable because the transparency of the finally obtained vinyl cross-linked polymer is further improved. still,
In the present invention, the synthetic resin does not include a vinyl group-containing polymer.

The polymerizable composition may further include, if necessary, surface-treated carbon black such as carbon black and polymer-grafted carbon black, reinforcing fine particles such as hydrated silica, and mica, talc, graphite and the like. Fillers other than the above-mentioned flaky or flat fillers for damping, such as calcium carbonate and aluminum hydroxide; zinc oxide, magnesium oxide, polyisocyanate compounds, hydrophilic silicic anhydride, etc. Thickeners; reinforcing materials such as glass fiber, glass cloth, potassium titanate fiber; plasticizers such as aromatic oils; flame retardants;
An antioxidant; a coloring agent such as a pigment;

Since the polymerizable composition having the above-mentioned composition is in the form of a low-viscosity liquid or prepreg, it is impregnated into a nonwoven fabric, glass cloth, glass fiber, or the like, laminated, and subjected to polymerization to form a composite. It can be used as a vibration damping material or applied to a substrate and subjected to polymerization to be used as a vibration damping paint.

According to the present invention, a vinyl-based crosslinked polymer according to the present invention can be obtained by polymerizing the polymerizable composition having the above constitution. The polymerization method of the polymerizable composition is not particularly limited, and for example, a polymerization method by heating;
Various known polymerization methods such as a polymerization method of irradiating radiation such as an ultraviolet ray or an electron beam; a polymerization method using a polymerization initiator such as a radical polymerization initiator; and the like can be employed. Also,
As a form of the polymerization reaction, for example, various known reaction forms such as bulk polymerization, suspension polymerization, emulsion polymerization, and dispersion polymerization can be employed. Accordingly, the obtained vinyl-based crosslinked polymer can be obtained in various shapes such as an elastomer, a film, a particle, and an emulsion, depending on the form of the polymerization reaction and the like. Among them, the method of adding a radical polymerization initiator to the polymerizable composition and performing bulk polymerization is the most simple production process, and the vinyl-based crosslinked polymer according to the present invention can be produced at low cost. Particularly preferred. And a suitable form in the case of carrying out the bulk polymerization industrially,
That is, as the molding method and the coating method, for example, cast molding, press molding, injection molding, RIM (reaction injection molding),
Extrusion molding, lamination, spray coating and the like can be mentioned.

Specific examples of the radical polymerization initiator include organic peroxides such as benzoyl peroxide, methyl ethyl ketone peroxide and t-amyl peroxy-2-ethylhexanoate; Organic azo compounds such as azobisisobutyronitrile; benzophenone, acetophenones, and acylphosphine oxide; The amount of the radical polymerization initiator added is
There is no particular limitation. Further, a polymerization accelerator may be used in combination with the radical polymerization initiator. Specific examples of the polymerization accelerator include organic metal salts such as cobalt octenoate and zinc stearate; aromatic tertiary amines such as dimethylaniline; and triphenylphosphine. Furthermore, polymerization regulators (so-called polymerization inhibitors)
And a photosensitizer may be used in combination with the radical polymerization initiator. Specific examples of the polymerization regulator include benzoquinone, paramethoxyphenol, hydroquinone and the like. When a polymerization accelerator, a polymerization regulator, a photosensitizer and the like are used, their addition amounts are not particularly limited.

Reaction conditions such as reaction pressure, reaction temperature and reaction time in the polymerization reaction are set so that the polymerization reaction is completed.
For example, it may be appropriately set according to the composition of the polymerizable composition; the presence or absence of addition of water, a solubilizing agent, and a synthetic resin; the polymerization method; the form of the polymerization reaction; is not. Further, the average molecular weight of the obtained vinyl-based crosslinked polymer is not particularly limited.

As described above, the vinyl-based crosslinked polymer according to the present invention comprises a polyfunctional vinyl compound, a metal salt compound having a plurality of polymerizable vinyl groups in the molecule, and another polymerizable copolymer with these compounds. A cross-linked polymer obtained by polymerizing a polymerizable composition containing a vinyl compound (a),
In addition to having excellent vibration damping characteristics with a dynamic loss of 0.9 or more in dynamic viscoelasticity measurement at z and having the above-described structure, the strength / strength such as tensile strength and tensile elongation / Excellent in various material properties such as elongation characteristics and compression set, and excellent in low creep property and heat resistance.

One of the reasons for this is that the polymerizable composition of the present invention comprises, as a crosslinkable compound, a polyfunctional vinyl compound and / or the above-mentioned vinyl copolymerizable with the above-mentioned metal salt compound (metal salt-containing vinyl monomer). The compound (a) is used in combination with the above polyfunctional vinyl compound and the above metal salt compound (metal salt-containing vinyl monomer). Simultaneous-Inter Penetrate (S-IPN: Simultaneous-Inter Penetrate)
It is conceivable that both cross-linking properties were exhibited by the formation of a network.

The vinyl crosslinked polymer obtained by the present invention is excellent in various material properties such as strength / elongation properties and compression set, and as a result, has low creep property.
Further, the vibration damping characteristics are excellent in a practical temperature range. Therefore, the vinyl-based crosslinked polymer is used in automobiles, OA equipment,
In a wide range of fields such as electric / electronic equipment and construction, it can be used as a polymer for vibration damping material used as a vibration damping material or as a vibration damping material itself, corresponding to a high performance requirement level. Further, the polymerizable composition used in the present invention and the vinyl-based crosslinked polymer which is a polymer (cured product) of the polymerizable composition have good workability in molding and coating in these various uses, and thus have good vibration damping properties. The productivity as a material can be improved. Further, the vinyl-based crosslinked polymer obtained by the present invention has good heat resistance, and the degree of change in hardness when heated at 150 ° C. for 500 hours is small. The degree of the change in hardness of the vinyl-based crosslinked polymer obtained in the present invention is preferably 30%.
Or less, more preferably 20% or less.

As described above, the above-mentioned vinyl cross-linked polymer according to the present invention is itself a cross-linked polymer having an excellent balance between vibration damping properties and material properties such as tensile strength, tensile elongation and compression set. Although it can be used as it is as a vibration damping material, it may be used in combination with, for example, other fillers or the like, as described above, depending on the intended use or field. By compounding the above-mentioned vinyl cross-linked polymer with another filler or the like, tan δ can be further improved, and the compound thus compounded may be used as a vibration damping material.

As the method of compounding the above-mentioned vinyl cross-linked polymer, a conventional method can be used. The compounding material and the amount used are those which do not impair the above-mentioned properties of the above-mentioned vinyl cross-linked polymer. If there is, it is not particularly limited.

The vibration damping material according to the present invention is
It comprises the above-mentioned vinyl-based crosslinked polymer, and since the above-mentioned vinyl-based crosslinked polymer is excellent in the above-mentioned properties, the vibration-damping material according to the present invention is also excellent in the above-mentioned properties, and There are no problems observed and no problems in workability at the time of manufacturing, the dynamic loss is large, and the balance between vibration damping properties and material properties such as tensile strength, tensile elongation, and compression set is excellent. When the vinyl-based crosslinked polymer is used as it is as the vibration-damping material, a vibration-damping material consisting of a pure crosslinked polymer and suitably usable in various application fields can be provided.

The method for producing a vinyl-based crosslinked polymer according to the present invention is characterized in that the polyfunctional vinyl compound and / or a metal salt compound having a plurality of polymerizable vinyl groups in the molecule are used. A metal salt having a plurality of vinyl groups in a molecule by reacting a metal compound with an unsaturated acid in the presence of at least one component selected from the group consisting of another copolymerizable vinyl compound (a) After obtaining a mixture containing the compound, without isolating the metal salt compound from the obtained mixture, finally, a polyfunctional vinyl compound,
This is a method of preparing and polymerizing a polymerizable composition containing a metal salt compound having a plurality of polymerizable vinyl groups in the molecule and the vinyl compound (a). As the unsaturated acid, the unsaturated acid contained in the vinyl compound (a) can be used.

The most characteristic feature of this method is that a polymerizable composition containing a crosslinkable monomer is polymerized to produce a crosslinked polymer (crosslinked rubber) at a stroke. That is, according to the above method, the above-mentioned vinyl-based crosslinked polymer is converted from a raw material (various monomers) for forming the above-mentioned polymerizable composition into a so-called 1 pot
Can be manufactured. This method does not require post-crosslinking, is a simple process, has good productivity, and is a method of forming the above vinyl-based crosslinked polymer (crosslinked polymer) according to the present invention at low cost, and is excellent in workability. It is a method.

Further, according to the above method, since a mixture containing a metal salt compound is obtained, the solubility of the metal salt compound is improved, and the concentration of the metal salt compound in the finally formed polymerizable composition is reduced. For example, the concentration can be increased without using a solubilizing agent. Therefore, by polymerizing the polymerizable composition, it is possible to stably introduce a large amount of a metal salt into the resin skeleton of the obtained polymer. That is, the degree of ionic crosslinking of the obtained polymer can be sufficiently increased. Therefore, it is possible to produce a vinyl-based crosslinked polymer excellent in various physical properties such as mechanical strength such as tensile strength and tear strength, heat resistance, oil resistance, weather resistance, and transparency.

Further, when the polymerizable composition contains a polymer having a plurality of polymerizable vinyl groups in a molecule as a polyfunctional vinyl compound together with a metal salt compound, the polymerizable composition is given an appropriate viscosity. In addition, the viscosity can be adjusted by utilizing the thickening effect of the addition of a thickener, for example. For this reason, it is possible to improve the mixability and dispersion stability of various additives that are optionally added to the polymerizable composition, and to handle and mold the polymerizable composition at the time of polymerization. , Workability, productivity and the like can be further improved. Moreover, when the polymerizable composition contains a polyfunctional vinyl monomer, the balance between the mechanical strength and various physical properties such as creep can be particularly improved.

[0078]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples, but the present invention is not limited thereto. In the examples and comparative examples, “parts” indicates “parts by weight”. Further, various physical properties of the cured product, that is, type A durometer hardness, tensile strength (tensile breaking strength), tensile elongation (tensile breaking elongation), and compression set are determined according to a test method such as JIS K6301. It was measured.

The tensile strength at break and tensile elongation at break were measured using a dumbbell No. 2 type test piece having a thickness of 3 mm at a tensile speed of 500 mm / min. The measurement of the compression set was performed using a cylindrical test piece having a diameter of 20 mm and a thickness of 12 mm.
After compressing at a compression ratio of 25% at 90 ° C. for 70 hours, the load was removed and the film was gradually cooled, and the thickness was measured 30 minutes after the load was removed.

The heat resistance of the cured product was evaluated by measuring the change in hardness (type A durometer hardness) of the cured product when heated in an oven at 150 ° C. for 500 hours.

Evaluation of the vibration damping properties of the cured product was performed by measuring dynamic viscoelasticity (tan δ). For the measurement of tan δ, a test piece having a thickness of 1.5 mm to 3 mm, a width of 3 mm to 6 mm, and a length of 35 mm was used. This test piece was measured by a dynamic viscoelasticity measuring device (RSA-II manufactured by Rheometrics).
Within a temperature range of −50 ° C. to −100 ° C., a heating rate of 5 ° C. /
And the dynamic storage elastic modulus (E ′) and dynamic loss elastic modulus (E ″) were measured at a frequency of 1 to 10 Hz. tan δ is obtained by the following equation: tan δ = E ′ / E ″.

Example 1 First, a monomer solution of a metal salt compound (metal salt-containing vinyl monomer) was synthesized. That is, a reactor having a capacity of 200 ml equipped with a stirrer, a cooling pipe, a thermometer, and a gas introduction pipe was charged with 2- as an unsaturated acid.
Methacryloyloxyethyl phthalic acid (manufactured by Shin-Nakamura Chemical Co., Ltd .; trade name "NK Ester CB-1") 70.5
Parts, 19.1 parts of n-butyl acrylate, and 1.
One part was charged and dissolved. Further, 9.3 parts of zinc oxide (two kinds of zinc flowers manufactured by Sakai Chemical Co., Ltd.) as a metal compound was added. The molar ratio of the above metal compound (zinc oxide), unsaturated acid (2-methacryloyloxyethyl phthalic acid) and water was 1.0: 2.1: 0.54. Next, the contents of the reactor were stirred at room temperature for 30 minutes, and then stirred for 70 minutes.
C., and reacted for 1 hour. The obtained reaction mixture was uniform and transparent, and maintained a uniform and transparent state even after cooling to room temperature. Further, the reaction mixture maintained a uniform and transparent state even after being left at room temperature for one week. From this, it was confirmed that the total amount of the added zinc oxide was converted to the zinc salt of 2-methacryloyloxyethylphthalic acid. Thereby, the monomer solution of the metal salt-containing vinyl monomer (hereinafter, referred to as
It was confirmed that a metal salt monomer solution (described as (1)) was obtained. The amount of the zinc salt as the metal salt-containing vinyl monomer in the metal salt monomer solution (1) was 76.0 parts. Incidentally, the amount of n-butyl acrylate in the metal salt monomer solution (1) is 19.1 parts.

Next, a polymerizable composition was prepared using the above metal salt monomer solution (1). That is, 30 parts of styrene and 67.5 parts of n-butyl acrylate as the vinyl compound (a), 2.5 parts of dimethacrylate of diethylene glycol diphthalate as the polyfunctional vinyl compound, and the above metal salt monomer solution (1) 13 By mixing 2 parts, a polymerizable composition according to the present invention was obtained. Table 1 shows the composition of the polymerizable composition.

Next, 100 parts of the above polymerizable composition was added to
0.5 part of a 55% by weight dimethyl phthalate solution of methyl ethyl ketone peroxide as a radical polymerization initiator and 0.5 part of a mineral spirit solution of cobalt octenoate (cobalt content of 8% by weight) as a polymerization accelerator were added, Mixed. Then, the obtained mixture was assembled using two glass plates and a silicone resin gasket, poured into a cell set to a predetermined thickness (1.5 to 3 mm), and polymerized at 65 ° C. for 7 hours. Thereafter, polymerization was further performed at 120 ° C. for 2 hours. As a result, a vinyl-based crosslinked polymer according to the present invention was obtained. Further, in order to obtain a predetermined cylindrical test piece for measuring the compression set described above, a cylindrical test piece for measuring the compression set including the vinyl-based crosslinked polymer according to the present invention was obtained using a predetermined cell. Next, various physical properties of the vinyl-based crosslinked polymer obtained in this example were measured by the above methods. Table 2 shows the results.

Example 2 In Example 1, the amount of styrene used in the polymerizable composition was changed from 30 parts to 49 parts and 2-ethylhexyl acrylate 48.5 was used instead of 67.5 parts of n-butyl acrylate. The same reaction and operation as in Example 1 were carried out except for using parts, to obtain a polymerizable composition according to the present invention. Table 1 shows the composition of the polymerizable composition.

Next, the same reaction and operation as in Example 1 were performed using the above polymerizable composition to obtain a vinyl-based crosslinked polymer according to the present invention. Various physical properties of the obtained vinyl-based crosslinked polymer were measured by the methods described above. Table 2 shows the results.

Example 3 Example 1 was repeated except that 30 parts of pt-butylstyrene was used as the vinyl compound (a) in place of 30 parts of styrene to prepare a polymerizable composition. The same reaction and operation were performed to obtain a polymerizable composition according to the present invention. Table 1 shows the composition of the polymerizable composition.

Next, the same reaction and operation as in Example 1 were carried out using the above polymerizable composition to obtain a vinyl-based crosslinked polymer according to the present invention. Various physical properties of the obtained vinyl-based crosslinked polymer were measured by the methods described above. Table 2 shows the results.

[Comparative Example 1] A reaction was conducted in the same manner as in Example 1, except that 30 parts of methyl methacrylate was used instead of 30 parts of styrene to prepare a polymerizable composition.
The operation was performed to obtain a polymerizable composition for comparison. Table 1 shows the composition of the polymerizable composition.

Next, a comparative polymer was obtained by performing the same reaction and operation as in Example 1 using the above polymerizable composition. Various physical properties of the obtained comparative polymer were measured by the methods described above. Table 2 shows the results.

COMPARATIVE EXAMPLE 2 Polymerization was carried out in the same manner as in Example 1 except that 30 parts of styrene was used instead of 40 parts of methyl methacrylate and 67.5 parts of n-butyl acrylate was replaced with 57.5 parts of 2-ethylhexyl acrylate. Except for preparing the composition, the same reaction and operation as in Example 1 were performed to obtain a polymerizable composition for comparison. Table 1 shows the composition of the polymerizable composition.

Next, a comparative polymer was obtained by performing the same reaction and operation as in Example 1 using the above polymerizable composition. Various physical properties of the obtained comparative polymer were measured by the methods described above. Table 2 shows the results.

Comparative Example 3 In Example 1, the amount of n-butyl acrylate used in the polymerizable composition was 67.
Change from 5 parts to 70 parts and metal salt monomer (1)
The reaction and operation were carried out in the same manner as in Example 1 except that was not used, to obtain a polymerizable composition for comparison. Table 1 shows the composition of the polymerizable composition.

Next, the same reaction and operation as in Example 1 were performed using the above polymerizable composition to obtain a comparative polymer. Various physical properties of the obtained comparative polymer were measured by the methods described above. Table 2 shows the results.

Comparative Example 4 A reaction and operation similar to those in Example 1 were carried out except that a polymerizable composition was prepared without using a dimethacrylate of diethylene glycol diphthalate. The composition was obtained. Table 1 shows the composition of the polymerizable composition.

Next, a comparative polymer was obtained by performing the same reaction and operation as in Example 1 using the above polymerizable composition. Various physical properties of the obtained comparative polymer were measured by the methods described above. Table 2 shows the results.

Example 4 First, an acrylic syrup, which is a monomer mixture containing a vinyl group-containing polymer as a polyfunctional vinyl compound, was synthesized. That is, a stirrer, a cooling pipe,
After charging 177 parts of methyl methacrylate and 22.8 parts of methacrylic acid in a 500-ml reactor equipped with a thermometer and a gas inlet tube, the inside of the reactor was purged with nitrogen gas. Next, while stirring this mixture, 0.1 part of 2,2′-azobisisobutyronitrile (radical polymerization initiator) and 0.28 part of n-dodecyl mercaptan (polymerization modifier) were added to the mixture. Was added. Thereafter, the internal temperature of the reactor was raised to 80 ° C. under a nitrogen gas stream, and the mixture was polymerized while maintaining the temperature.

When the degree of polymerization reaches about 40%, that is, when the amount of non-volatile components (methyl methacrylate / methacrylic acid copolymer, ie, polymer (A)) reaches about 40% by weight. Then, 37.6 parts of glycidyl methacrylate, 0.15 part of benzyltriphenylphosphonium chloride (catalyst), and 0.02 part of hydroquinone (polymerization inhibitor) were added and mixed to the reaction solution, and the reactor was rapidly cooled.

After quenching, the internal temperature of the reactor was again raised to 100 ° C. while stirring under an air atmosphere, and the mixture was reacted for 23 hours while maintaining the temperature. That is, a vinyl group was introduced into the side chain of the polymer (A) by reacting the polymer (A) with glycidyl methacrylate. Thereby, a mixture containing a methyl methacrylate / methacrylic acid copolymer having two or more vinyl groups in a side chain and unreacted methyl methacrylate and methacrylic acid, that is, a methacrylic syrup containing a methacrylic ester polymer (Hereinafter, referred to as syrup (A)).

The syrup (A) was transparent and had a nonvolatile content of 45.1% by weight. In addition, syrup (A)
The acid value of the methacrylic acid ester polymer is 21.0 m
gKOH / g. Then, the difference between the acid value of the polymer (A) and the acid value of the methacrylate polymer is 4
Since it was 1.7 mgKOH / g, it was found that 66.5% of the carboxyl groups of the polymer (A) were converted to vinyl groups. A polymerizable composition was prepared using the syrup (A) having the above composition.

In preparing the polymerizable composition, the amount of styrene used in the polymerizable composition was changed from 30 parts to 15 parts in Example 1 and 2.5 parts of dimethacrylate of diethylene glycol diphthalate was used in Example 1. The same reaction and operation as in Example 1 were carried out except that 15 parts of the above syrup (A) were used, to obtain a polymerizable composition according to the present invention. Table 1 shows the composition of the polymerizable composition.

Next, the same reaction and operation as in Example 1 were performed using the above polymerizable composition to obtain a vinyl-based crosslinked polymer according to the present invention. Various physical properties of the obtained vinyl-based crosslinked polymer were measured by the methods described above. Table 2 shows the results.

Comparative Example 5 In Example 1, 15 parts of methyl methacrylate was used instead of 30 parts of styrene, and the syrup (A) obtained in Example 4 was replaced with 2.5 parts of dimethacrylate of diethylene glycol diphthalate. ) Was used, except that 15 parts were used.
The operation was performed to obtain a polymerizable composition for comparison. Table 1 shows the composition of the polymerizable composition.

Next, a comparative polymer was obtained by performing the same reaction and operation as in Example 1 using the above polymerizable composition. Various physical properties of the obtained comparative polymer were measured by the methods described above. Table 2 shows the results.

[0105]

[Table 1]

[0106]

[Table 2]

As shown in Table 2, the vinyl crosslinked polymers obtained in Examples 1 to 4 were excellent in each of the above-mentioned physical properties. On the other hand, the polymer obtained in Comparative Example 3 did not use a metal salt-containing vinyl monomer, and had low tensile strength and heat resistance. Further, the polymer obtained in Comparative Example 4 did not use a polyfunctional vinyl compound, had a large permanent compression set, and was poor in rubber elasticity.

Further, the vinyl-based crosslinked polymers obtained in Examples 1 to 4 have a large tan δ value at normal temperature and a maximum tan δ value in fluctuation temperature measurement, and a tan δ value of 0.2 or more. The practical temperature range (ΔT) shown is wide. These facts indicate that these vinyl crosslinked polymers exhibit excellent vibration damping properties over a wide temperature range. On the other hand, the respective tan δ values and ΔT values obtained in Comparative Examples 1, 2, and 5 were smaller than the values of the polymers obtained in Examples 1 to 4, and were low in damping properties.

As described above, from Examples 1 to 4, the polymerizable composition according to the present invention can be easily converted into a polymer by a simple method. The vinyl-based crosslinked polymer according to the present invention has excellent properties such as strength / elongation properties, compression set, heat resistance, etc.
It can be seen that the material has low creep properties and excellent vibration damping properties, and can be used as a vibration damping material in a wide range of applications and fields.

[0110]

According to the constitution of the present invention, the problems of performance of the conventional vibration damping material and the problem of workability at the time of manufacturing are caused due to diversification of uses of the vibration damping material and enhancement of required performance. The present invention has the effect of providing a vinyl-based crosslinked polymer which is suitable for a vibration-damping material, has a large dynamic loss, is excellent in vibration-damping properties, a simple production method thereof, and a vibration-damping material. Play. The vinyl-based crosslinked polymer is 2
A high dynamic loss of 0.9 or more in dynamic viscoelasticity measurement at 5 ° C. and 10 Hz is realized.
Has excellent vibration damping properties. The vinyl-based crosslinked polymer has a tensile strength and a tensile elongation, because the polymerizable composition uses a polyfunctional vinyl compound and a metal salt compound having a plurality of polymerizable vinyl groups in a molecule in combination. It is excellent in various material properties such as strength / elongation characteristics and compression set, etc., can realize low creep, and is also excellent in heat resistance. The vinyl-based cross-linked polymer is, for example, as set forth in claim 2
Alternatively, it has excellent material properties as described in claim 3. Therefore, according to the configuration of the present invention, the vibration damping property and the various material properties described above, preferably, the tensile strength at 25 ° C. is 50 kgf / cm ² or more, and the tensile elongation at 25 ° C. is 3
It satisfies at least one, more preferably two, and particularly preferably three of the physical properties of a compression set of 50% or less when compressed at 90 ° C. for 70 hours at a compression ratio of 25% or more with a compression ratio of 25% or more. To provide a crosslinked vinyl polymer. The vinyl-based crosslinked polymer is, as described above,
It has an excellent balance between vibration damping properties and material properties such as tensile strength, tensile elongation, and compression set, and can be used as it is as a vibration damping material. Therefore, according to the present invention, it is possible to provide a vibration damping material which is made of a pure crosslinked polymer and can be suitably used in various fields of application. According to the above configuration, there is no restriction on use, and there is no problem in terms of ease of use such as compounding as a vibration damping material and moldability. In addition, by blending, as the vinyl compound (a), an aromatic vinyl compound such as styrene and / or a styrene derivative into the polymerizable composition, a vinyl compound exhibiting high vibration damping properties in a wide temperature range can be obtained. The effect is that a crosslinked polymer and a molding material can be provided.

Further, according to the method of the present invention, it is possible to provide a method capable of producing the above-mentioned vinyl-based crosslinked polymer in a simple process with good productivity, good workability and at low cost. This has the effect.

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Claims (7)

[Claims] 1. A polymerizable composition comprising a polyfunctional vinyl compound, a metal salt compound having a plurality of polymerizable vinyl groups in a molecule, and another vinyl compound (a) copolymerizable with the compound. A vinyl-based crosslinked polymer having a dynamic loss in dynamic viscoelasticity measurement at 25 ° C. and 10 Hz of 0.9 or more. 2. The tensile strength at 25 ° C. is 50 kgf / c.
m ² or more and / or a tensile elongation at 25 ° C. of 30
The vinyl-based crosslinked polymer according to claim 1, wherein the amount is 0% or more. 3. The crosslinked vinyl polymer according to claim 1, wherein the compression set is 50% or less when compressed at 90 ° C. for 70 hours at a compression ratio of 25%. 4. The method according to claim 1, wherein said vinyl compound (a) contains an aromatic vinyl compound.
Item 14. The vinyl-based crosslinked polymer according to item 1. 5. The polymerizable composition comprises 0.1 to 30% by weight of a polyfunctional vinyl compound, 0.1 to 30% by weight of a metal salt compound, and 5 to 60% by weight of an aromatic vinyl compound.
The vinyl-based crosslinked polymer according to claim 4, wherein the vinyl-based crosslinked polymer is contained in an amount of at least 1% by weight. 6. A mixture containing a metal salt compound having a plurality of vinyl groups in a molecule by reacting a metal compound with an unsaturated acid in the presence of a polyfunctional vinyl compound and / or vinyl compound (a). After obtaining, from the obtained mixture, without isolating a metal salt compound having a plurality of vinyl groups in the molecule, finally, the polyfunctional vinyl compound and a plurality of polymerizable vinyl groups in the molecule The method for producing a vinyl-based crosslinked polymer according to claim 1, wherein a polymerizable composition containing the metal salt compound and the vinyl compound (a) is prepared and polymerized. 7. A vibration damping material comprising the vinyl cross-linked polymer according to any one of claims 1 to 5.