JPS6124445A - Vibration-damping material having excellent workability and oil resistance - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vibration damping material that is excellent in processability such as deep drawing and bending.

In recent years, the impact of noise from transportation such as automobiles, trains, and vehicles, as well as noise and vibration from factories and construction sites, on surrounding residents is increasing day by day, and has become a major social problem.As a way to solve this problem, Research and development of vibration-absorbing materials in which the material itself has vibration-absorbing ability is progressing, and vibration-damping materials with high vibration-absorbing performance and suitable for various purposes are being used as structural members of vehicles, ships, industrial machinery, iron bridges, etc. Conventionally, such damping materials include vinyl acetate-ethyl acrylate copolymer (Japanese Patent Publication No. 45-35662) and a copolymer obtained by grafting a mixture of styrene and acrylonitrile onto vinyl acetate-ethylene copolymer. Combination (Special Public Service 1977-
Laminated structures having a composition such as No. 17064) as an intermediate layer, and materials in which a filler such as calcium carbonate is added to bicemen are known.

However, when these are made into a laminated structure with a metal plate, although they have vibration absorption ability in a specific temperature range, the adhesion with the metal plate is insufficient, and the elastic modulus of the intermediate layer composition is insufficient. The fact is that it has disadvantages such as poor deep drawing and bending workability with mechanical presses due to low heat resistance, and poor heat resistance, so it has difficulties in secondary workability as a vibration damping metal plate. It is.

Furthermore, in applications that are immersed in machine oil, such as automotive oil pans or machine tool parts, if a resin material with poor oil resistance is used, the adhesive strength with the steel plate will decrease, resulting in poor workability (or poor vibration damping performance). There were obvious disadvantages.

The disadvantages of the workability of conventional vibration-damping metal plates using mechanical presses, etc. include, for example, during deep drawing, the edge of the metal plate may shift, or in severe cases, the two stacked upper and lower metal plates may become vibration-damping. In addition to the problem of separation from the elastic resin layer and opening, the low elasticity of the resin layer also causes waving on the surface of the molded product and wrinkles on the curved corner surfaces. In addition, a 180° bending process called hemming process is carried out to process the edges of vibration-damping metal plates, but such severe processing causes the metal plate surface to become even more wavy and wrinkled, making it difficult to put it into practical use. It had become unbearable.

In view of these problems, the present invention has been developed by deep drawing.

The purpose of this invention is to provide a vibration damping material that has excellent workability such as bending and has excellent damping performance.

As a result of intensive studies to provide such an excellent damping material, the present inventors found that the elongation rate at a temperature of 20°C is 5 (1 or more) and the peak loss coefficient (tan δ) is 1120. At least one resin selected from the group of saponified ethylene-vinyl acetate copolymer, saponified ethylene-acrylic ester copolymer, and saponified ethylene-methacrylic ester copolymer in the range of ~80°C (
The inner and outer surfaces of Lyrum made of A) have a higher shear modulus than resin (A) at a temperature of 20°C, and a peak temperature of loss coefficient (tan δ) of 140 to 1 at an elongation rate of 10 inches or more.
80°C range, and the adhesive strength with the metal plate is 31ip/a at 20°C and 180° beering.
The vibration-damping material, which is characterized by sandwiching a multilayer film provided with polyolefin resin (B) with a polyolefin resin (B) with a polyolefin resin (B) with a polyolefin resin (B) with a polyolefin resin (B) having a polyolefin resin having a polyolefin resin (B) having a polyolefin resin (B) and a polyolefin resin (B) having a polyolefin resin having a polyolefin resin (B) having a polyolefin resin (B) and a polyolefin resin (B) having a polyolefin resin with a polyolefin resin (B) having a polyolefin resin that has a polyolefin resin (B) and a polyolefin resin (B) with a polyolefin resin of The present invention was achieved by discovering that it has both absorption performance and oil resistance.

According to the present invention, it has good adhesion to metal plates even under relatively low temperature adhesive processing conditions, and has a high elastic modulus.
The multilayer resin structure with different elongation rates provides excellent workability even under severe processing conditions during deep drawing and bending, and the multilayer resin structure with different peak loss coefficient (tan δ) temperatures allows for an extremely wide temperature range. A damping material that exhibits high vibration absorption over a long period of time is obtained, and its damping properties and workability do not deteriorate even when exposed to machine oil or the like for a long period of time.

The present invention will be explained in detail below.

The elongation rate at the temperature of 20°C used in the present invention is 50%.
The loss factor (peak temperature of tan) is 1120 to 8.
In the resin, which is in the range of 0°C, saponified ethylene-vinyl acetate copolymer 1, saponified copolymer of ethylene and alkyl esters of acrylic acid such as methyl, ethyl, and propyl, and methyl methacrylate and ethylene are used. , saponified polymers, and the like.

Among these, saponified ethylene-vinyl acetate copolymer is superior in terms of vibration damping performance, workability, and oil resistance.

Here, the degree of saponification can be freely selected, but considering all aspects of vibration damping performance, workability, and oil resistance, it is 70 to 98.
It is desirable that the degree of saponification be 1.

In the present invention, the elastic modulus at a temperature of 20°C used for the inner and outer layers is higher than that of the inside of the resin, the elongation rate is 10 inches or more, the peak temperature of the loss coefficient (tan δ) is in the range of 140 to 180°C, and the metal plate Adhesive strength with temperature 20℃, 180
° The polyolefin resin (hereinafter referred to as Resin B) that has a peeling strength of 3 Q/cm or more belongs to the category of olefin resins, but contains monomers selected from unsaturated carboxylic acids and their anhydrides. It is a crystalline polyolefin modified with one type or a mixture of two or more types, and the crystalline polyolefin (C1 is low,
Monoolefin polymers such as medium or high density polyethylene, polypropylene, polybutene-1, ethylene-
Mention may be made of olefin copolymers such as propylene copolymers, ethylene-butene copolymers, and mixtures of these polymers or mixtures of these polymers with small amounts of rubbery substances. Among these, low, medium or high density polyethylene and polypropylene are preferred. Among these, cotton-like low density polyethylene is more preferred.

The unsaturated aliphatic carboxylic acids and their anhydrides (D) used as one of the modifiers of the modified crystalline polyolefin include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, and maleic anhydride. Examples include acids and itaconic anhydride, among which acrylic acid, methacrylic acid and maleic anhydride are preferred. Various methods can be used to produce this modified crystalline polyolefin, but monomers selected from unsaturated carboxylic acids and their anhydrides and a radical generator are added to the crystalline polyolefin in a closed system. A preferred method is a step of reacting at a temperature higher than the melting point of the polyolefin (preferably 170° C. or higher).

In addition, by forming a mixture of the above modified polyolefin, an amorphous polymer (E), and/or an ethylene polymer, superior adhesion to a metal plate and vibration absorption temperature range strength can be obtained. It is preferable to obtain an effective power of 5.

Examples of the amorphous polymer include (meth)esteric acid ester polymers, polyisobutylene, 1.2-polyptadiene, acrylonitrile-styrene copolymers, petroleum resins, and the like. Among these, (meth)acrylic acid ester polymers are preferred.

Moreover, as the ethylene polymer (F), at least one kind of polymer selected from ethylene homopolymer, ethylene-α olefin copolymer, and ethylene-unsaturated ester copolymer can be mentioned.

In the method of carrying out the present invention, the inside of the resin is molded into a film by a conventional molding method such as inflation processing, calendering, darning processing, T-die processing, or the like. A method for providing at least one resin M (Bl) of a modified crystalline polyolefin composition on the inner and outer surfaces of this film is to form a laminated film by forming each film and dry laminating, heat laminating, etc. Existing techniques may be used, such as a method of extrusion laminating at least one resin of a modified crystalline polyolefin composition into a film in a resin, a method of simultaneously molding a laminated film by a multilayer extrusion method, and in particular a method of multilayer extrusion. The method of forming by this method has advantages such as ease of forming, interlayer adhesion of the resulting film,
Preferable in terms of cost.

The thickness of the intermediate layer resin and the inner and outer layer resins, which have different peak temperatures of elastic modulus, elongation rate, and loss coefficient, is determined by the thickness of the intermediate layer resin in terms of excellent processability and high vibration absorption in a wide temperature range. It is preferably 20% or more and 95% or less of the total film thickness, most preferably 80 or more and 90% or less.

If the total thickness is 30μ or more, vibration damping properties are good, but in order to have good workability such as bending and drawing, it is necessary to have a total thickness of 100μ or more.
It is preferably less than μ, most preferably 30 μ or more and 60 μ or less.

As a method for producing the damping material of the present invention, any method such as a normal batch method or continuous heat press method can be applied. For example, there is a method of interposing the resin composition between two metal plates and bonding them under heat and pressure. Adhesion is generally 150-2
Performed at 20'C.

The present invention will be specifically explained below using examples.
These are illustrative, and the present invention is not limited thereto.

In the examples, the content of maleic anhydride was determined by using phenolphthalein as an indicator after dissolving the resin.
It was determined by neutralization titration with alcoholic NaOH. In addition, the elastic modulus and loss coefficient (tan) of the inner and outer layers and the intermediate layer film were measured using Toyo Baldwin Rheopybron (IIOH2), and the elongation rate was 200.
It was determined by the tensile speed of wiZ.

The loss coefficient (η) representing the vibration absorbing ability of the damping material was measured using forced vibration using the mechanical impedance method (central vibration) at a frequency of 1000 Hz and a temperature of 20 to 130°C. Adhesion test adhesion to cold rolled steel plate (0.8m)/
The resin composition (50μ)/cold rolled steel plate (0,8111
1) (7) Configuration: 190°C, 5 minutes, 30 Kp/as”
(7) Glue under the conditions, 180' (7) angle, 50m/
Evaluation was made at a tensile speed of minutes.

The saponification degree is measured using an alkaline saponification method.

For workability, the molds shown in FIGS. 1 and 2 were used to test bending back and drawing workability, respectively, and evaluate slippage, peeling, wrinkles, etc. FIG. 1 (al is a cross-sectional view of the bending test mold.

In the figure, 1, 2.3 are mold members, 4 is a spacer, and 5 is a sample. Further, 2R, SR, etc. indicate curvature.

FIG. 1(b) is a perspective view of a molded product tested by bending back. In the figure, part A, part B, and part 0 indicate evaluation observation parts, respectively.

FIG. 2 (λ) is a cross-sectional view of the drawability test mold. In the figure, 1, 2, 3, 4, and 5 indicate mold members, and 6 indicates a sample. Further, 5R indicates the curvature, and 500.560 indicates the diameter of the corresponding portion.

FIG. 2(b) is a perspective view of a molded product tested for drawability.

In the same figure, 1 shows the A part wrinkle, 2 shows the 7 lunge wrinkle, and 3 shows the evaluation observation part of the board slip.

Examples 1 to 3 0.7% by weight of maleic anhydride and 0.1% by weight of [-butyl peroxylaurate were added to linear low-density polyethylene (manufactured by CdF Chimie) with a melt index of 4f/1o/lc. Mixed for 2 minutes using a Henschel mixer, then heated to 30 m at 190°C.
Kneading with extruder 1. It was later made into pellets.

Hereinafter, the above mixture will be referred to as the resin for the inner and outer layers.A multilayer inflation device equipped with two-type and three-layer inflation dies (diameter 150) was used.
The above resins for the inner and outer layers were supplied through an extruder No. 111111 at a melt die temperature of 180°C and a die temperature of 180°C, and the intermediate layer was supplied with ethylene-vinyl acetate copolymer Evatate ■ (melt index 3f/10 min) manufactured by Sumitomo Chemical Co., Ltd. )75
Melting zone: 170℃, die temperature: 180℃
The resin supplied to each layer was laminated inside the die, and the tubular body with the three-layer sandwich inch structure was pulled at a take-up speed of 7.0 m/min and a blow-up pressure of 2.0. A film having a three-layer sandwich structure having a folding diameter of 470 mm and a thickness of each layer shown in Table 1 was obtained. The obtained film was heat-pressed (190° C., 5 minutes, 30 Kf/♂) between cold-rolled steel plates with a thickness of 0.8 to measure adhesion, workability, and vibration absorption. The second result is
- Shown in Table 4 and Figure 3.

FIG. 3 is a diagram showing the relationship between temperature and loss coefficient (η) of the damping material.

Comparative Examples 1 to 3 The resins for the inner and outer layers and the resin for the intermediate layer of Examples 1 to 3 were individually passed through an extruder with a diameter of 30 mm using an inflation device equipped with an inflation die (diameter 10.0+e+). , the above resin was melted in a melting zone of 170°C and a die temperature of 17°C.
The tubular body that could be supplied at 0° C. was taken at a take-up speed of 7/min and a blow-up pressure of 2.0 to obtain a film having a fold diameter of 300 and a thickness shown in Table 6.

Using the obtained film, heat and press (180℃, 5 minutes, 30Kf/am2) between cold rolled steel plates with a thickness of 0.8mm.
Adhesion, workability and vibration absorption properties were measured.

The results are shown in Tables 2 to 4 and FIG.

Comparative Example 3 uses ethylene-vinyl acetate copolymer Evatate ■ (melt index 3f/10 minutes) manufactured by Sumitomo Chemical Co., Ltd. as the resin for the intermediate layer of the composition of Example 3 for oil resistance comparison.
That is. Comparative data on oil resistance is shown in Table 7.

As is clear from Table 1, Table 3, Table 5, Table 6, Tables 2 to 7, and FIG. A product with excellent vibration damping properties and oil resistance over a wide temperature range was obtained. On the other hand, the composite with only the inner and outer layers is inferior as a vibration damping material because peeling and wrinkles are observed during deep drawing and composite #4 with only the middle layer has no adhesion to metal. Met.

[Brief explanation of the drawing]

Figure 1! a+ is a cross-sectional view of the bending test mold. FIG. 1 (+) is a perspective view of a molded product tested by bending back. FIG. 2 (@) is a cross-sectional view of the drawability test mold. FIG. 2(b) is a perspective view of a molded product tested for drawability. FIG. 3 is a diagram showing the relationship between temperature and loss coefficient (η) of the damping material. Figure 1 Figure 2

Claims (9)

[Claims] (1) A vibration damping material composed of a damping layer made of thermoplastic resin sandwiched between two metal plates, where the resin layer has a loss coefficient (tan δ) when the elongation rate at a temperature of 20°C is 50% or more. The peak temperature of -1
At least one resin selected from the group of saponified ethylene-vinyl acetate copolymers, saponified ethylene-acrylic ester copolymers, and saponified ethylene-methacrylic ester copolymers in the range of 20 to 80°C. (A
) has a shear modulus higher than that of resin (A) at a temperature of 20°C, and a peak temperature of loss coefficient (tan δ) of -40 to 18 at an elongation rate of 10% or more.
0℃ range, and the adhesive strength with the metal plate is at temperature 2.
A vibration damping material with excellent workability, characterized by being provided with a polyolefin resin (B) that has a yield of 3 kg/cm or more when peeled at 0°C and 180°. (2) The damping material according to claim 1, wherein the resin (A) is a saponified ethylene-vinyl acetate copolymer. (3) The resin (B) is a monomer selected from crystalline polyolefin (C) and unsaturated carboxylic acids and their anhydrides (
Claim 1, which is a composition comprising a polymer modified with one or a mixture of two or more of D), or further comprising an amorphous polymer (E) and/or an ethylene polymer (F) Damping material listed. (4) The crystalline polyolefin (C) in the resin (B) is
The damping material according to claim 1, which is linear low density polyethylene. (5) The crystalline polyolefin (C) in the resin (B) is
The damping material according to claim 1, which is a polyolefin selected from the group consisting of low, medium or high density polyethylene and polypropylene. (6) The control according to claim 1, wherein the unsaturated carboxylic acid and its anhydride (D) in the resin (B) are compounds selected from the group consisting of acrylic acid, methacrylic acid, and maleic anhydride. Shaking material. (7) The vibration damping material according to claim 1, wherein the amorphous polymer (E) in the resin (B) is a (meth)acrylic acid ester polymer. (8) The amorphous polymer (E) in the resin (B) is 1,2-
The damping material according to claim 1, which is polyptadiene, polyisobutylene, acrylonitrile-styrene copolymer, or petroleum resin. (9) The ethylene polymer (F) in the resin (B) is at least one polymer selected from ethylene homopolymer, ethylene-α olefin copolymer, and ethylene-unsaturated ester copolymer. A vibration damping material according to claim 1.