JP2002275321A - Vibration-damping material composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration-damping material composition which exhibits vibration-damping capability at about room temperature, to enhance the vibrationdamping capability at such a temperature, and to widen the temperature range wherein a higher vibration-damping capability is exhibited. SOLUTION: This composition contains (A) an ethylene/unsaturated carboxylic acid/unsaturated carboxylic ester terpolymer and (B) a tackifier in a wt.ratio of (A/B) of (60/40)-(98/2).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in vibration damping performance of an ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester terpolymer.

[0002]

2. Description of the Related Art Conventionally, vinyl chloride resin (PVC) and chlorinated polyethylene have been widely used as a raw material resin for a vibration damping sheet. However, in response to a demand for non-halogenation, an ethylene-based resin containing a polar comonomer component has been used. The use of copolymers is expected.

For example, Japanese Patent Application Laid-Open No. 62-152750 discloses that 20 to 300 parts by weight of 100 parts by weight of a terpolymer of ethylene, an unsaturated carboxylic acid and an ester or vinyl ester of an unsaturated acid is used. A viscoelastic composition for a vibration damping material comprising an inorganic filler is described.

Japanese Patent Application Laid-Open No. Hei 3-111144 discloses that a tackifying resin 3 is used for 100 parts by weight of an ethylene-acrylic acid copolymer having an acrylic acid content of 10 to 30% by weight and a melt index of 100 to 3000 g / 10 minutes.
It describes a resin composition for a vibration-damping metal plate, characterized by adding about 30 parts by weight and 0.5 to 3.0 parts by weight of an antioxidant.

Further, Japanese Patent Application Laid-Open No. 2000-281838 discloses a high attenuation material composition containing the following components (A) to (C), wherein the content of the above component (B) is The content of the component (C) is set in the range of 10 to 200 parts by weight with respect to 100 parts by weight of the component (A). (A) a base polymer having at least one of an acidic and a basic polar side chain, (B) a damping agent, and (C) a tackifier. I have.

[0006]

Among the polar group-containing ethylene copolymers, typical ethylene-vinyl acetate copolymer (EVA) and ethylene-ethyl acrylate copolymer (EEA) exhibit vibration damping performance. However, there is a problem that the temperature range in which the heating is performed is considerably lower than the room temperature.

As one guideline for this temperature range,
There is a tan delta (tan δ) peak temperature in the dynamic viscoelastic data. In the case of an ethylene / unsaturated ester binary copolymer such as EVA or EEA, the tan delta peak temperature is usually around -30 to -10 ° C. Shift to higher temperature.
In particular, in the ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester terpolymer, the tan delta peak temperature approaches room temperature when the ester content is not so high. However, since the height of the tan delta peak (= damping performance) is proportional to the ester content, there is a problem that a terpolymer having a preferable temperature range is insufficient in terms of damping performance. is there.

An object of the present invention is to solve this problem and to improve the vibration damping performance at this temperature while maintaining the temperature at which the vibration damping performance is exhibited at a temperature near room temperature, thereby exhibiting a higher vibration damping performance. The idea is to expand the temperature range.

[0009]

According to the present invention, an ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester terpolymer (A) and a tackifier (B) are mixed with A / B =
A vibration damping material composition is provided which is contained in a weight ratio of 60/40 to 98/2, more preferably 70/30 to 90/10. In the vibration damping material composition of the present invention, 1. The terpolymer (A) has an unsaturated carboxylic acid ester content of 1 to 30% by weight, particularly 2 to 17% by weight; 2. the unsaturated carboxylic acid ester is an alkyl ester of (meth) acrylic acid and the alkyl group has 1 to 10 carbon atoms, most preferably isobutyl (meth) acrylate; The unsaturated carboxylic acid content of the terpolymer (A) is 1
3. to 30% by weight; 4. the unsaturated carboxylic acid is (meth) acrylic acid; The tackifier (B) has a ring and ball method softening point of 12
5. Be at least one of rosin, rosin derivative, terpene resin, petroleum hydrocarbon resin, cumarone resin, alkylphenol resin and xylene resin at 0 ° C. or lower; In the dynamic viscoelasticity test, the tan delta peak temperature measured at a frequency of 110 Hz is preferably in the range of 10 to 35 ° C.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, an ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester terpolymer is selected as a base polymer of a vibration damping material composition, and a tackifier is added to the terpolymer. Are combined at a specific quantitative ratio.

See the examples below. In the ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester terpolymer (A) selected in the present invention, the advantage that the tan delta peak temperature is at or near room temperature is achieved. However, it can be seen that there is no temperature range in which the tan delta peak value is 0.5 or more (see Comparative Examples 1 and 2).

On the other hand, when the tackifier (B) is blended with the terpolymer (A) in an amount within the range specified in the present invention, the tan delta peak value is improved to 0.5 or more. And a tan delta peak value of 0.
The temperature range of 5 or more can be extended to about 10 degrees or more (Examples 1 and 2), which is an unexpected effect of the present invention.

In the present invention, it is also important to use the terpolymer (A) and the tackifier (B) at the above-mentioned quantitative ratios. That is, when the amount of the tackifier (B) is less than the above range, the tan delta peak value tends to be lower than when the amount is within the above range, which is not preferable in terms of vibration damping performance. On the other hand, when the amount of the terpolymer (A) is less than the above range, it becomes difficult to form an extruded sheet as compared with the case where the amount is within the above range,
In addition, the physical properties of the vibration damping sheet are undesirably reduced.

[Ternary Copolymer] The base polymer used in the present invention comprises an ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester terpolymer. In this terpolymer, the content of the unsaturated carboxylic acid ester is preferably in the range of 1 to 30% by weight, particularly 2 to 17% by weight, from the viewpoint of practical vibration damping performance. That is, when the ester content is lower than this range, the tan delta peak temperature becomes higher, while when the ester content becomes higher than this range, the tan delta peak temperature becomes lower, and the temperature range in which the vibration damping performance is exhibited is from room temperature to the vicinity thereof. Tends to be difficult to set.

The terpolymer used in the present invention has an unsaturated carboxylic acid content of 1 to 30% by weight, particularly 2 to 2% by weight.
It is preferable to be within the range of 0% by weight in terms of practical vibration damping performance. That is, when the unsaturated carboxylic acid content is lower than this range, the tan delta peak temperature is lower, while when the unsaturated carboxylic acid content is higher than this range, the tan delta peak temperature is higher, and the vibration damping performance is exhibited. It tends to be difficult to set the temperature range from room temperature to its vicinity.

The ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester terpolymer used in the present invention contains the above-mentioned monomer components in the above-mentioned quantitative ratio. Of course, two or more different unsaturated carboxylic acid components and unsaturated carboxylic acid esters may be used.

Examples of the unsaturated carboxylic acid ester include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate,
N-Amyl (meth) acrylate, isoamyl (meth) acrylate, n-hexyl (meth) acrylate, (meth)
2-ethylhexyl acrylate, (meth) acrylic acid n
Octyl and the like. However, the above (meth) acrylic acid means acrylic acid or methacrylic acid. As the unsaturated carboxylic acid ester, those having 1 to 10 carbon atoms in the alkyl group in the ester are preferable, and isobutyl acrylate is most preferable.

Examples of the unsaturated carboxylic acid component include acrylic acid, methacrylic acid, ethacrylic acid, fumaric acid, maleic acid, monomethyl maleate, monoethyl maleate, and maleic anhydride. Acrylic acid or methacrylic acid is preferred.

The ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester terpolymer may be used at 190 ° C., 21
Melt flow rate at 60 g load is 0.1 to 10
It is preferable to use a material having a thickness of 0 g / 10 min, particularly about 1.0 to 60 g / 10 min, in view of the physical properties and workability of the sheet.

The ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester terpolymer can be obtained by radically copolymerizing ethylene, unsaturated carboxylic acid and unsaturated carboxylic acid ester at high temperature and high pressure. it can.

[Tackifier] Tackifiers include rosin, hydrogenated rosin, disproportionated rosin, polymerized rosin, rosin derivatives such as rosin ester, terpene resin, terpene phenol resin, aromatic terpene resin, hydrogenated terpene resin , Petroleum hydrocarbon resin, cumarone resin,
At least one of an alkylphenol resin and a xylene resin
Seeds are used. The tackifier used preferably has a softening point in the ring and ball method of 120 ° C. or lower in terms of compatibility with the terpolymer, and further has a glass transition point (Tg) in the range of room temperature to around room temperature in terms of vibration damping performance. Is preferred.

[Damping Material Composition] The damping material composition of the present invention is obtained by melt-kneading the terpolymer (A) and the tackifier (B) in the above-mentioned quantitative ratio. When the material of the present invention is used for producing a vibration-damping sheet, various additives known per se can be blended within a range that does not impair the object of the present invention. Examples of such additives include viscosity modifiers, inorganic fillers, damping agents, tackifiers, ultraviolet absorbers, flame retardants, flame retardants, pigments, dyes, lubricants, antistatic agents, blocking. Examples include an inhibitor, a foaming agent, a foaming aid, a crosslinking agent, and a crosslinking aid.

For example, an ionomer can be blended with the vibration damping material composition of the present invention for the purpose of adjusting the viscosity. As such an ionomer, an ionomer of ethylene and an unsaturated carboxylic acid or further an unsaturated carboxylic acid ester can be used. The polymerization rate of the unsaturated carboxylic acid in the random copolymer is 1 to 40% by weight, and the polymerization rate of the unsaturated carboxylic acid ester is usually 0 to 3%.
0% by weight. Here, preferred examples of the unsaturated carboxylic acid include:
Acrylic acid or methacrylic acid, and a preferable example of the other copolymerizable monomer is (meth) acrylic acid ester. Examples of the metal ion in such an ionomer include lithium, sodium, potassium, magnesium, barium, lead, tin, zinc, and aluminum. Particularly, lithium, sodium, magnesium, zinc, and a combination of two or more thereof are preferable. The degree of neutralization by metal ions is usually 5 to 100%, preferably 20 to 8%.
0%. 190 ° C. as the ionomer,
The melt flow rate under a load of 2160 g is 0.01
It is preferable to use one having a viscosity of ２０20 g / 10 min, especially 0.1０．１10 g / 10 min. The ionomer is preferably used in an amount of up to 50% by weight, especially from 5 to 30% by weight, based on the composition.

Fillers, reinforcing agents, coloring agents and the like can be blended as long as the flexibility of the material is not impaired. For example, calcium carbonate, clay, kaolin, talc, silica, diatomaceous earth, mica powder, Asbestos, alumina, barium sulfate, aluminum sulfate, calcium sulfate, basic magnesium carbonate, molybdenum disulfide, graphite, glass fiber, glass sphere, shirasu balloon, carbon fiber, carbon black, titanium oxide, iron powder, ferrite, zinc flower, Bengal, ultramarine, navy blue, azo pigment,
Nitroso pigments, lake pigments, phthalocyanine pigments and the like can be blended. This filler or the like is used in an amount of 8 per composition.
It can be incorporated in an amount of 0% by weight or less, especially 5 to 70% by weight.

Further, as an attenuating agent, N-cyclohexyl-2-benzothiazolylsulfenamide,
Benzothiazole-based compounds such as N, N-dicyclohexyl-2-benzothiazolylsulfenamide;
Benzotriazole compounds such as (2'-hydroxy-3 ', 5'-di-t-butylphenyl) -5-chlorobenzotriazole and hindered phenols, for example, octadecyl 3- (3,5-di-t- Butyl-4-hydroxyphenyl) propionate; pentaerythryl-tetrakis [3- (3,5-di-tert-butyl-4-
Hydroxyphenyl) propionate]; 1,3,5-
Trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene; 1,3,5
-Tris- [ethylene-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] -s-triazine-2,4,6- (1H, 3H, 5H) trione; 3-tris (2-methyl-4-hydroxy-5-t-butylphenol-butane; 4,4'-methylene-bis (2,6-di-t-butylphenol); hexamethylene glycol-bis [β- (3 , 5-di-t-
Butyl-4-hydroxyphenol) propionate]
6- (4-hydroxy-3,5-di-t-butylanilino) -2,4-bis-octyl-thio-1,3,5-triazole; 2,2′-thio [diethyl-bis-3
(3,5-di-t-butyl-4-hydroxyphenol) propionate]; 2,2′-methylene-bis (4
-Methyl-6-t-nonylphenol) and the like, and these can be used alone or as a mixture. These dampening agents are present at 40 per composition.
It can be used in amounts of up to 5% by weight, in particular from 5 to 30% by weight.

Further, as the viscosity modifier, various waxes such as microcrystalline wax, paraffin wax, montan wax, polyethylene wax, polyethylene oxide wax, Fischer-Tropsch wax and the like can be used. These viscosity modifiers can be used in amounts of up to 30% by weight, in particular from 2 to 20% by weight, based on the composition.

The material of the present invention is blended with the above components as necessary, and then melt-kneaded with a kneader known per se such as a Banbury mixer, a pressure kneader, a single screw extruder, a twin screw extruder, or a roll. A process such as pelletization is performed, and the resulting product is formed into a molded product by molding processing means such as extrusion molding, injection molding, compression molding, or the like depending on the intended object.

For example, a film or sheet can be produced by extrusion through a flat die,
It can also be manufactured by calendering.
Also, the tube can be manufactured by extrusion through a ring die.

The vibration damping material composition according to the present invention includes, for example, a vibration damping sheet for a hard disk drive of a personal computer, a sound absorbing film for a video camera, other OA equipment, home appliances, housing building materials, industrial materials, sports goods, and health. It is useful as a vibration damping material, sound absorbing material, and sound insulating material for articles, shoes, bicycles, motorcycles, automobile parts, and the like.

[0030]

Next, the present invention will be described specifically with reference to examples and comparative examples. 1. Table 1 shows the ethylene copolymers used in the Examples and Comparative Examples.
Table 2 shows the tackifier resins.

[0031]

[Table 1]

[0032]

[Table 2]

2. Performance Evaluation The dynamic viscoelasticity measurement method of the obtained composition is as follows.・ Testing machine: DVE-V4 FT Rheospectral (longitudinal vibration type dynamic viscoelasticity measuring device, manufactured by Rheology Co., Ltd.) ・ Measurement conditions: tensile mode, frequency 110 Hz, measurement temperature range -60 ° C. to 70 ° C., heating rate 3 ° C / min ・ Measurement items: storage modulus, loss modulus, tan delta

Example 1 Copolymer 1 and tackifier resin 1 were mixed at a weight ratio of 80:20, and a screw type twin screw extruder (screw diameter 30 mm, co-rotation, L / D =
35) and melt-kneaded under the conditions of a barrel temperature of 140 ° C. and a screw rotation speed of 150 min ⁻¹ . The obtained blend was press-formed into a 2 mm thick sheet, and the dynamic viscoelasticity was measured. Table 3 shows the results.

Example 2 The copolymer 2 and the tackifying resin 2 were mixed at a weight ratio of 70:30 and supplied to a batch-type small kneader (Laboplast mill).
The mixture was melt-kneaded at a temperature of 60 ° C and a blade rotation speed of 60 min- ¹ . The obtained blend was press-formed into a 2 mm thick sheet, and the dynamic viscoelasticity was measured. Table 3 shows the results.

[Comparative Examples 1 and 2] The dynamic viscoelasticity of the copolymer 1 used in Example 1 and the copolymer 2 used in Example 2 were measured. Table 3 shows the results. These copolymers containing no tackifier resin component had a smaller tan delta near room temperature than the above examples.

Comparative Example 3 Copolymer 3 and tackifying resin 1 were mixed at a weight ratio of 80:20, and melt-kneading, press molding and dynamic viscoelasticity measurement were performed in the same manner as in Example 1. Table 3 shows the results. In the blend of the copolymer 3 and the tackifier resin 1 containing no acrylate component, the tan delta peak was in a temperature range slightly higher than room temperature, and the peak value was also slightly smaller than that in the above example.

Comparative Example 4 Copolymer 4 and tackifying resin 1 were mixed at a weight ratio of 80:20, and the same melt kneading, press molding and dynamic viscoelasticity measurements as in Example 2 were performed. Table 3 shows the results. Copolymer 4, which is a kind of ethylene-acrylic rubber, had a high acrylate concentration, and the blend with tackifier resin 1 had a large tan delta peak value, but the temperature range was lower than room temperature.

[0039]

[Table 3]

[0040]

According to the present invention, an ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester terpolymer is selected as the base polymer of the vibration damping material composition, and the terpolymer is tackified. By combining the fires at a specific quantitative ratio, the temperature at which the damping performance is exhibited is set to a temperature near room temperature, and at the same time, the damping performance at this temperature is improved, and the temperature range at which higher damping performance is exhibited is increased. Can be expanded.

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Claims (8)

[Claims] 1. An ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester terpolymer (A) and tackifier (B) in a weight ratio of A / B = 60/40 to 98/2. A vibration damping material composition, characterized in that: 2. The vibration damping material composition according to claim 1, wherein the content of the unsaturated carboxylic acid ester in the terpolymer (A) is in the range of 1 to 30% by weight. 3. The method according to claim 1, wherein the unsaturated carboxylic acid ester is an alkyl ester of (meth) acrylic acid, and the alkyl group has 1 to 10 carbon atoms. Damping material composition. 4. The vibration damping material composition according to claim 1, wherein the unsaturated carboxylic acid ester is isobutyl methacrylate. 5. The vibration damping material composition according to claim 1, wherein the unsaturated carboxylic acid content of the terpolymer (A) is in the range of 1 to 30% by weight. object. 6. The vibration damping material composition according to claim 1, wherein the unsaturated carboxylic acid is (meth) acrylic acid. 7. The tackifier (B) is at least one of rosin, rosin derivative, terpene resin, petroleum hydrocarbon resin, cumarone resin, alkylphenol resin and xylene resin having a softening point in the ring and ball method of 120 ° C. or lower. The vibration damping material composition according to any one of claims 1 to 6, wherein 8. In the dynamic viscoelasticity test, a frequency of 110
Tan delta peak temperature measured in Hz from 10 to 35 ° C
The vibration damping material composition according to any one of claims 1 to 7, wherein