JPH0160412B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention particularly relates to a new and useful vibration absorbing material with excellent damping performance. In recent years, there has been a demand for high-performance vibration-absorbing materials to prevent vibrations and noise from automobiles, ships, factory machinery, construction machinery, etc. For example, in the automobile industry, lighter and higher-performance materials are needed, especially from the perspective of energy conservation. In addition, there is a desire for something that can be easily attached to a substrate. By the way, various materials are currently used as such vibration-absorbing materials, such as asphalt-based, synthetic rubber-based, synthetic resin-based, and combinations of these materials. The current situation is that a material that exhibits good performance and also has good adhesion workability to substrates has not yet been obtained. In particular, synthetic resin-based materials have the advantage of having a wider applicable temperature range and higher vibration absorption performance than asphalt-based materials, but require a special adhesive when bonding to the substrate. Not only that, but the method of applying such an adhesive also requires special operations such as troweling and pressing, so it is not without problems. On the other hand, although asphalt-based materials are easily bonded together by heat fusion during the automobile paint drying process, the applicable temperature range is narrow and the vibration absorption performance is low, so it is quite difficult to obtain the desired absorption performance. When I was told that something thick was required,
The reality is that we still haven't gotten enough. However, in view of the above-mentioned circumstances, the inventors of the present invention have developed a material that has high vibration absorption performance, can be made lightweight, can be applied over a wide temperature range, and has excellent workability during bonding. As a result of intensive research in order to develop, on a specific vibration absorbing sheet mainly made of vinyl acetate-olefin copolymer,
The present invention was completed based on the discovery that a vibration absorbing material obtained by laminating sheets with a specific configuration and good adhesive properties meets these objectives. That is, the present invention provides a vibration-absorbing sheet containing at least 5% by weight of a vinyl acetate-olefin copolymer, (a) a vinyl acetate-olefin copolymer, (b) asphalt, and (c) at least two The purpose of the present invention is to provide a laminated vibration-absorbing material made by laminating sheets with good adhesion, each of which contains an inorganic powder having a specific gravity as an essential component. Here, the vinyl acetate-olefin copolymer used in the vibration-absorbing sheet constituting the vibration-absorbing material of the present invention is not particularly limited in terms of the type and proportion of its copolymer components or its molecular weight. However, under normal conditions of use, the vinyl acetate content is 40 to 90% by weight, and the Mooney viscosity [ML ₁₊₄ (100℃ )] of 10 or more is suitable. Of course, as long as the features of the present invention are not impaired,
Copolymers using olefins such as ethylene, propylene, or putene instead of ethylene may also be used, and copolymers such as those made by copolymerizing (meth)acrylic acid, their esters, or various mixtures thereof with vinyl acetate may be used. It may be a copolymer, or even a copolymer using vinyl propionate instead of vinyl acetate. The content of the vinyl acetate-olefin copolymer in the vibration-absorbing sheet is suitably at least 5% by weight, more preferably from 15 to 70% by weight. If it is less than 5% by weight, the applicable temperature range will be narrow, the vibration absorption performance will be low, and the molding workability will be poor, so that the purpose of the present invention cannot be achieved. In order to obtain this vibration-absorbing sheet, not only the vinyl acetate-olefin copolymer but also other known and commonly used polymers as well as various commonly used fillers or additives may be used in combination. Examples of polymers include plasticized soft vinyl chloride resins and polyolefin polymers.
Of course, a mixture of these may be used. On the other hand, typical fillers or additive components include high specific gravity inorganic fillers such as mica, talc, or asbestos, which are particularly recommended because they have high vibration absorption performance and can be applied over a wide temperature range. It is something that will be done. The amount of the polymer, filler, or additive used as a combined component is not particularly limited, and may be appropriately determined depending on the intended use and the conditions for molding or use. Usually, a suitable range is 30 to 85% by weight of the vibration absorbing sheet. This vibration-absorbing sheet can be prepared by molding it in accordance with a conventional method using equipment such as a roll, a calendar roll, a Banbury mixer, an extrusion molding machine, or an injection molding machine. It will be done. On the other hand, the adhesive sheet with good adhesive properties constituting the vibration absorbing material of the present invention contains, as essential components, a vinyl acetate-olefin copolymer (a), asphalt (b), and an inorganic material having a specific gravity of at least 2. The proportion of each of these essential components is not particularly limited, but from the viewpoint of vibration absorption performance and adhesiveness, vinyl acetate-olefin copolymer The preferred range is 5 to 60 parts by weight of the coalesce (a), 95 to 40 parts by weight of asphalt (b), and 10 to 200 parts by weight of the high specific gravity inorganic powder (c). Each of these essential components has the following effects, and if the copolymer (a) component is absent, the adhesion to the vibration-absorbing sheet described above will be reduced. Asphalt (b)
If the component is missing, the adhesion to a substrate such as a steel plate will be reduced, and if the inorganic powder component (c) is missing, the vibration absorption performance will be reduced. The copolymer (a) constituting the adhesive sheet
The vinyl acetate-olefin copolymer used in the vibration-absorbing sheet described above can be used as is, but from the viewpoint of compatibility with asphalt (b) and the applicable temperature range, vinyl acetate Vinyl acetate-ethylene copolymers with a content of 25 to 87% by weight are preferred. Of course, it is not limited to such vinyl acetate-ethylene copolymer, and the above-mentioned vibration-absorbing sheet may be used in consideration of adhesion with the vibration-absorbing sheet, vibration-absorbing performance, flexibility, etc. It goes without saying that the vinyl acetate-olefin copolymer may be appropriately selected from among the vinyl acetate-olefin copolymers for use. In addition, asphalt (b) which is an essential component of the adhesive sheet, if it is a known and commonly used one,
Natural asphalt, asphalt tight, straight asphalt, bronze asphalt, etc. having a penetration of 0 to 100 mm are particularly preferred, although any of them can be used and is not particularly limited. Furthermore, the above-mentioned high specific gravity inorganic powder (c), which is an essential component of the adhesive sheet, refers to a powdered inorganic compound of at least 2, preferably 2.5 or more, and the above-mentioned inorganic filler. Besides barrel talc, mica or asbestos,
All known and commonly used materials such as titanium oxide, clay, magnesium oxide, zinc carbonate, magnesium carbonate, and calcium carbonate can be used, but mica, talc, and asbestos are preferred from the viewpoint of vibration absorption performance and fillability. . The vibration-absorbing material of the present invention is obtained by laminating each vibration-absorbing sheet prepared by a conventional method using the various components listed above and an adhesive sheet. In obtaining the absorbent material, other fillers, flame retardants, colorants, stabilizers, crosslinking agents, etc. may be added as necessary within a range that does not impair the features of the present invention. Moreover, it can also be used by adding a foaming agent to foam it. Further, the adhesive sheet can be obtained by hot melt mixing or by processing with a roll, calendar roll, Banbury mixer, extrusion molding machine, etc., but the adhesive sheet can be laminated onto the vibration absorbing sheet, As a method of bonding, a method may be used, such as bonding the sheets together at the time of manufacturing the sheets, or bonding sheets produced separately by heat-sealing them. Furthermore, the laminated vibration absorbing material of the present invention thus obtained can be freely bonded to various substrates with complex structures by simply applying heat; It goes without saying that the invention is applicable not only to structures but also to various substrates made of known and commonly used materials, such as steel plates with complex structures such as corrugated or acute-angled cross-sectional shapes. The vibration-absorbing material of the present invention used in this case is not particularly limited in the thickness or thickness ratio of each vibration-absorbing sheet and the adhesive sheet that constitute the vibration-absorbing material, and is suitable for use. Various changes can be made as appropriate and as long as the features of the present invention are not impaired. The thus obtained laminated vibration absorbing material of the present invention can be used in an extremely wide range of applications as a laminated material for various mechanical parts or equipment, including automobiles. Next, the present invention will be specifically explained with reference to Examples and Comparative Examples. In the following, all parts and percentages are based on weight unless otherwise specified. Example 1 As a vibration absorbing sheet, a vinyl acetate-ethylene copolymer having a Mooney viscosity (hereinafter simply referred to as Mooney viscosity) of ML ₁₊₄ (100°C) of 25 and a vinyl acetate content of 81% was used. 50 parts of polyvinyl chloride, 75 parts of polyvinyl chloride, 25 parts of di-n-octyl phthalate
50 parts of plasticized polyvinyl chloride resin obtained from 1 part and 3 parts of stabilizer and
60S” [mica manufactured by Kuraray Co., Ltd.] and 70 parts,
After kneading these with a mixing roll and forming them into a sheet, they are press-formed to a diameter of 0.7 mm.
A sheet of uniform thickness was obtained. On the other hand, as an adhesive sheet, Mooney viscosity is 40.
20 parts of vinyl acetate-ethylene copolymer with a vinyl acetate content of 60%, 50 parts of straight asphalt with a penetration of 0-20, and "Suzolite.
After 30 parts of ``Mica 60S'' were hot-melted and mixed, a uniform sheet with a thickness of 0.3 mm was obtained in the same manner as above. Both of the obtained sheets were bonded together using a hot press to obtain a laminated sheet-like vibration absorbing material. Next, this laminated sheet is cut into a length of 30 cm.
So, the width is 1.5cm and the thickness is 0.8mm.
3141 steel plate (made by Nippon Test Panel Industries Co., Ltd.) and heated at 150°C for 15 minutes to heat-fuse the structure to create a laminated structure as shown in Figure 1. Got the product. Afterwards, regarding this product, Bru¨el & Kjaer, Denmark.
The loss coefficient (η) at a frequency of 100 Hz was determined by the resonance method using a complex elastic modulus measuring device manufactured by KK. The results and adhesive properties are summarized in Table 2,
Table 3 also shows the loss coefficient (η) at each temperature. Comparative Example 1 A commercially available asphalt/inorganic filler-based vibration absorbing material was press-molded to obtain a 2.0 mm thick sheet. Next, this was placed on the steel plate used in Example 1 and heated at 150° C. for 15 minutes to heat-seal the product to obtain a laminated product having the structure shown in FIG. Thereafter, the loss coefficient (η) at each temperature was determined for this comparative laminate. The results are shown in Table 3. Examples 2 to 4 and Comparative Examples 2 to 5 Vibration absorbing materials were prepared by repeating the same operations as in Example 1, except that the components and proportions were changed as shown in Table 1. A laminated product was obtained by bonding the material to a steel plate. Thereafter, loss coefficients (η) were determined for the various laminates obtained. The results are shown in Table 2.

【table】

[Table] As is clear from Table 2, when the material of the present invention is used, it is known that it has high vibration absorption performance and good adhesiveness. On the other hand, each vinyl acetate-olefin copolymer, which is an essential component of the material of the present invention,
It is also known that the object of the present invention cannot be met if (a), asphalt (b) or powdery inorganic filler (c) is missing.

[Table] As is clear from Table 3, the material of the present invention has higher vibration absorption performance over a wide temperature range than commercially available vibration damping sheets even though it is thin. As described above, the laminated vibration-absorbing material of the present invention not only has high vibration-absorbing performance over a wide temperature range from low to high temperatures, but also has extremely easy adhesion to a substrate. It also has excellent adhesive properties. In addition, because of these high-performance materials,
Among other things, because of its high vibration absorption performance, the material can be made considerably thinner in use than conventional products, and therefore has the advantage of being lighter in weight. This can be said to have great industrial significance from the perspective of energy conservation.

[Brief explanation of drawings]

FIG. 1 is a partially sectional perspective view showing the structure of a laminated product obtained by bonding the material of the present invention to a steel plate. In the figure, 1... vibration absorbing sheet, 2... adhesive sheet, 3... steel plate.

Claims (1)

[Claims] 1 On a vibration absorbing sheet containing at least 5% by weight of vinyl acetate-olefin copolymer,
A laminate characterized by laminating together sheets with good adhesive properties, each of which has a vinyl acetate-olefin copolymer (a), asphalt (b), and an inorganic powder (c) having a specific gravity of at least 2 as essential components. Vibration absorbing material.