JPH09249784A - Resin composition for vibration-damping material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition having high rigidity and an excellent balance between vibration-damping properties and impact strength and being useful for automolive components, household electric appliances and OA machines. SOLUTION: This composition comprises 2-50 pts.wt. copolymer (A) comprising 50-90wt.% alkyl (meth)acrylate with a 4-12 C alkyl and 10-50wt.% vinyl cyanide and/or aromatic vinyl and having a glass transition temperature of -40 to below 0 deg.C, 2-90 pts.wt. glutaric anhydride copolymer (B) comprising 10-90wt.% glutaric anhydride and 90-10wt.% alkyl unsaturated carboxylate and 8-48 (the total of components A, B and C is 100 pts.wt.) thermoplastic resin (e.g. styrene resin) other than components A and B.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition for a vibration damping material having a high rigidity and a balance between vibration damping performance and impact resistance.

[0002]

2. Description of the Related Art In recent years, problems of noise and vibration have arisen due to changes in the living environment.
Reduction of noise and vibration is required in the A field. For example, a material that reduces vibration of a radiator fan in an automobile, noise generated by a motor in a home electric appliance field, and vibration of an optical disk in an OA field is used or required. As a vibration damping material and a vibration damping material, it is desirable that the structure itself has a vibration damping property, but in general, a material with high rigidity that can be a structure has a small vibration damping property, and conversely a material having a large vibration damping property is It is difficult to use a resin composition having a vibration damping property as a structure as it is because it has a trade-off relationship of low rigidity. As a means for overcoming the problem, in JP-A-6-41443, a copolymer comprising an acrylic acid ester monomer and / or a methacrylic acid ester monomer and another comonomer having a glass transition temperature of 0 ° C. or higher. However, the balance between vibration damping properties and physical properties, particularly impact resistance at room temperature and low temperature, was not sufficient.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a resin composition for a vibration damping material which has an excellent balance of vibration damping performance and physical properties, particularly impact resistance at room temperature and low temperature. is there.

[0004]

Means for Solving the Problems The present inventors have made intensive studies to solve the above problems, and as a result, have completed the present invention. That is, according to the present invention, 50 to 90% by weight of a (meth) acrylic acid alkyl ester monomer having an alkyl group having 4 to 12 carbon atoms, a vinyl cyanide monomer and / or an aromatic vinyl monomer 10 to 10% by weight. 2 to 50 parts by weight of a copolymer (A) having a glass transition temperature of −40 ° C. or higher and lower than 0 ° C., which comprises 50% by weight, and glutaric anhydride 10 to 90.
% By weight and unsaturated carboxylic acid alkyl ester 90 to 10
Glutaric acid anhydride-based copolymer (B) 2% by weight
90 parts by weight and 8 to 48 parts by weight of a thermoplastic resin (C) other than (A) and (B) (however, (A) + (B) +
(C) = 100 parts by weight) to provide a resin composition for a vibration damping material.

The present invention will be described in more detail below. Examples of the (meth) acrylic acid ester monomer having an alkyl group having 4 to 12 carbon atoms which constitutes the copolymer (A) of the present invention include n-butyl acrylate, isobutyl acrylate and n-methacrylic acid. Butyl, isobutyl methacrylate, pentyl acrylate, pentyl methacrylate, hexyl acrylate, hexyl methacrylate, heptyl acrylate, heptyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, octyl acrylate, octyl methacrylate, Examples thereof include n-nonyl acrylate and isononyl acrylate. One kind or two or more kinds can be used. Of these, n-butyl acrylate and n-butyl methacrylate are particularly preferable.

As the vinyl cyanide monomer constituting the copolymer (A), acrylonitrile, methacrylonitrile, chloroacrylonitrile and the like can be mentioned, and one kind or two or more kinds can be used. Of these, acrylonitrile is particularly preferable. Examples of the aromatic vinyl monomer include styrene, α-methylstyrene, ο-methylstyrene, p-methylstyrene, ο-ethylstyrene, p-ethylstyrene and the like, and one kind or two or more kinds can be used. . Of these, styrene is particularly preferable.

The above-mentioned carbon number of 4 to 4 constituting the copolymer (A)
The proportion of the (meth) acrylic acid ester monomer having 12 alkyl groups is 50 to 90% by weight, preferably 60 to 8%.
0% by weight. If the proportion is less than 50% by weight, the vibration damping property is poor, and if it exceeds 90% by weight, the impact resistance becomes low.
Not preferred.

The copolymer (A) can be polymerized by solution polymerization, emulsion polymerization or the like using a peroxide as a catalyst. The number average molecular weight is usually 10,000 to 1,000,000, preferably 20,000 to 500,000. If the number average molecular weight is less than 10,000, the impact resistance is insufficient, and if it exceeds 1,000,000, the workability is insufficient.

The glass transition temperature of the copolymer (A) can be adjusted depending on the types of monomers used and the ratio thereof. The glass transition temperature of the copolymer (A) in the present invention is -40 ° C or higher and lower than 0 ° C, preferably -30.
It is desirable that the temperature is not less than 0 ° C and less than 0 ° C. When the copolymer (A) having a glass transition temperature of less than −40 ° C. is used, sufficient vibration damping property cannot be obtained at room temperature. Further, when the copolymer (A) having a temperature of 0 ° C. or higher is used, the impact resistance at room temperature and low temperature is lowered. In the present invention, the glass transition temperature of the copolymer (A) was measured by using a differential scanning calorimeter (DSC) manufactured by Seiko Denshi Co., Ltd., at a temperature rising rate of 20 ° C./min, under a nitrogen atmosphere, and in a sample 20
It is measured under the condition of mg.

The unsaturated carboxylic acid alkyl ester constituting the glutaric anhydride copolymer (B) of the present invention includes methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, Examples include n-butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate, with methyl methacrylate being particularly preferred.

The proportion of glutaric anhydride constituting the glutaric anhydride copolymer (B) is 10 to 90% by weight. If the amount of glutaric anhydride exceeds 90% by weight (unsaturated carboxylic acid alkyl ester is less than 10% by weight), the impact resistance is poor, and glutaric anhydride is less than 10% by weight (unsaturated carboxylic acid alkyl ester is 90% by weight). % Is exceeded, the compatibility between the copolymer (A) and the thermoplastic resin (C) decreases, and the vibration damping property deteriorates, which is not preferable. Examples of the method for producing the copolymer (B) composed of glutaric anhydride and an unsaturated carboxylic acid alkyl ester include a method of copolymerizing glutaric anhydride and an unsaturated carboxylic acid alkyl ester, methacrylic acid and methacrylic acid. A method of heat-treating a copolymer with an acid ester can be mentioned, and the latter method is particularly preferable.

The above (A) and (B) used in the present invention
Examples of the other thermoplastic resin (C) include, but are not limited to, styrene resins, polycarbonate resins, polyester resins, polyamide resins, polyolefin resins, acrylic resins, polyphenylene ether resins, polyacetal resins, polysulfone resins, and the like. Not a thing. Of these, styrene resins are particularly preferable.

The styrene resin used in the present invention includes polystyrene, HIPS resin, AS resin and ABS.
Examples thereof include resins, ACS resins, AES resins, MBS resins, AAS resins, and these styrene resins can be used alone or in combination of two or more. Of these, ABS resin is particularly preferable.

Examples of the polycarbonate resin used in the present invention include aromatic polycarbonate resins, aliphatic polycarbonate resins, and aliphatic-aromatic polycarbonate resins. Generally, a polymer or copolymer obtained by polymerizing bisphenols such as 2,2-bis (4-oxyphenyl) alkane type, bis (4-oxyphenyl) ether type, bis (4-oxyphenyl) sulfide or sulfoxide type. There
It is a polymer using bisphenols optionally substituted with halogen.

The polyester resin used in the present invention comprises an aromatic dicarboxylic acid such as polyethylene terephthalate (PET), polypropylene terephthalate, polybutylene terephthalate (PBT), polypentamethyl terephthalate and polyhexamethyl terephthalate, and a dihydric alcohol. The polyester resin obtained and the so-called polyarylate resin which is an aromatic polyester resin obtained from an aromatic dicarboxylic acid and an aromatic diphenol can be mentioned. Specific examples of the polyarylate resin include a polyester resin and a copolyester resin containing bisphenol A and terephthalic acid or isophthalic acid. Of these, particularly preferred is PBT.

As the polyamide resin, H2N- (CH2) x-NH2 (where x is an integer of 3 to 12) is used.
Linear diamine and HOOC- (CH2) y-C
The thing produced by condensation with the linear diamine acid represented by OOH (In formula, y is an integer of 2-12) can be used. Preferable examples of these polyamide resins include nylon 6,6, nylon 6,10, nylon 6,12, nylon 4,6, nylon 3,4, nylon 6,9, nylon 6, nylon 12, nylon 11, nylon 4 Etc.

The resin composition for damping material of the present invention comprises 2 to 50 parts by weight of the above-mentioned copolymer (A), 2 to 90 parts by weight of glutaric anhydride copolymer (B) and a thermoplastic resin ( C) 8
~ 48 parts by weight (however (A) + (B) + (C) = 100
Parts by weight). When the amount of the copolymer (A) is less than 2 parts by weight, the vibration damping property is poor, and when it exceeds 50 parts by weight, the impact resistance is poor, which is not preferable. When the glutaric anhydride copolymer (B) is less than 2 parts by weight, the vibration damping property is poor, and when it exceeds 90 parts by weight, the impact resistance is poor, which is not preferable. Thermoplastic resin (C)
Is less than 8 parts by weight, the impact resistance is inferior, and if it exceeds 48 parts by weight, the vibration damping property is inferior.

The resin composition for vibration damping material of the present invention may contain an inorganic filler. The inorganic filler is fibrous,
There are scaly, spherical, and other shapes. Examples of the fibrous filler include glass fiber, carbon fiber and metal fiber. The glass fiber is a glass chopped strand which is usually commercially available for resin reinforcement, and has an average diameter of 5 to 20 μm.
m, and the length is preferably 0.5 to 10 mm. Examples of the flaky filler include mica, glass flakes, and mica. It is preferable that the ratio of the average diameter to the average thickness is 25 or more. Examples of the spherical filler include glass beads, calcium carbonate, calcium sulfate and the like, and those having an average diameter of 5 to 100 um are preferable. Others, whiskers,
It may be a needle-shaped or the like metal oxide polymorphic crystal. The amount of these inorganic fillers used is usually 0 to 250 with respect to 100 parts by weight of the composition comprising the copolymer (A), the glutaric anhydride copolymer (B) and the thermoplastic resin (C). Parts by weight, preferably 5 to 200 parts by weight. If it exceeds 250 parts by weight, the physical properties of the resin composition for vibration damping material will deteriorate.

The resin composition for damping material of the present invention comprises (A),
The components (B) and (C) and, if necessary, an inorganic filler are mixed, and the mixture is mixed with various extruders at a temperature of 200.
It can be obtained by melt mixing at ˜250 ° C. Further, various additives can be added to the resin composition for vibration damping material of the present invention, if necessary. As the additives, known antioxidants, ultraviolet absorbers, lubricants, flame retardants, antistatic agents, colorants and plasticizers can be used.

Next, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to these. In addition, the number of parts and% are all shown on a weight basis.

[Examples] Copolymers (A-1 to A-4, X-1 to X-2) n-butyl acrylate and / or n-methacrylic acid
Butyl, styrene, and acrylonitrile were polymerized by a known emulsion polymerization method to obtain a copolymer. The composition of the copolymer is shown in Table 1.

Glutaric anhydride copolymer (B-1 to B
-3, Y-1, Y-2) A copolymer of methacrylic acid and methyl methacrylate having the copolymer composition shown in Table 2 was melt-kneaded at 280 ° C. with a twin-screw extruder to give a table. A glutaric anhydride copolymer having the composition shown in 2 was obtained. The composition of the copolymer was measured by the CHO elemental analysis method.

Styrenic resin (C- 1 to C -2) C-1; polybutadiene rubber latex (weight average particle diameter 0.43 μ, gel content 8 by a known emulsion polymerization method ).
5 parts by weight, solid content 50 parts by weight) 100 parts by weight, styrene 35 parts by weight, acrylonitrile 15 parts by weight are graft-polymerized, and rubber resin 50 parts by weight ABS resin (acetone soluble part has an intrinsic viscosity of 0.6 (23 ° C.). , Dimethylformamide),
Acrylonitrile content of acetone-soluble component 26% by weight)
I got

C-2: Similar to C-1, 20 parts by weight of polybutadiene rubber latex (weight average particle diameter 0.43 μ, gel content 85% by weight, solid content 50% by weight), styrene 56 parts by weight, acrylonitrile 24 A part by weight was subjected to graft polymerization to obtain an ABS resin having a rubber content of 20% by weight (intrinsic viscosity of acetone-soluble matter of 0.6 (23 ° C., dimethylformamide), acrylonitrile content of acetone-soluble matter of 26% by weight).

The above-mentioned copolymer (A), glutaric anhydride-based copolymer (B) and styrene-based resin (C) were mixed in the proportions (parts) shown in Table 3 and then mixed in a twin-screw extruder. It was melt-kneaded at a cylinder temperature of 210 ° C. and pelletized.
The obtained pellets were injection-molded using a 4-ounce injection molding machine under the conditions of a cylinder temperature of 210 ° C. and a mold temperature of 50 ° C. to prepare test pieces, and physical properties were measured. In addition, in the examples, various physical properties were evaluated by the following methods.

Impact resistance: Measured at 25 ° C. and −30 ° C. according to ASTM D256. The unit is kg · cm / cm.

Flexural Modulus Measured according to ASTM D790. The unit is kg /
cm ² .

Vibration damping property Bending mode at 25 ° C. using Seiko Denshi DMS110
Was measured for Tan δ at a frequency of 10 Hz to evaluate the vibration damping property. That is, the larger this value is, the better the vibration damping property is.

[0029]

[Table 1]

[0030]

[Table 2]

[0031]

[Table 3]

[0032]

The resin composition for a vibration damping material of the present invention has a high rigidity and an excellent balance of vibration damping performance and impact strength, and is useful as an automobile part, a home electric appliance, and an OA equipment part.

Claims (2)

[Claims] 1. A (meth) acrylic acid alkyl ester monomer 50-90 having an alkyl group having 4 to 12 carbon atoms.
2 to 50 parts by weight of a copolymer (A) having a glass transition temperature of −40 ° C. or higher and lower than 0 ° C., which comprises 10% by weight to 50% by weight of vinyl cyanide monomer and / or aromatic vinyl monomer. And 2 to 90 parts by weight of a glutaric anhydride copolymer (B) consisting of 10 to 90% by weight of glutaric anhydride and 90 to 10% by weight of an unsaturated carboxylic acid alkyl ester, and other than (A) and (B) Other thermoplastic resin (C) 8 to 48
A resin composition for a vibration damping material, which comprises parts by weight (however, (A) + (B) + (C) = 100 parts by weight). 2. The resin composition for a vibration damping material according to claim 1, wherein the thermoplastic resin (C) is a styrene resin.