JPS622982B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a composite vibration damping laminate, and more particularly to a composite vibration damping laminate comprising a polymer layer and a metal layer that have damping performance against metal. In recent years, noise from industrial machinery and structures, as well as automobiles, which are essential to social life, has come to the fore as a social problem, and as a result, various noise prevention measures have been required. Conventional specific noise prevention measures include sound insulation,
Many methods have been used to combine materials with different functions, such as sound-absorbing, vibration-proofing, and damping materials. Meanwhile, in the automobile industry, in addition to noise prevention measures, weight reduction is being promoted in order to cope with fuel efficiency regulations and energy supply issues that are becoming increasingly strict due to the trends of the times. Examples include thinning steel plates for panels, or introducing aluminum alloys and plastic materials as substitutes for steel materials. On the other hand, as automobiles become lighter, the vibrations of the automobile itself tend to become more intense, leading to an increase in noise.
Therefore, how to reduce vibration will be an important issue in the future. Recently, as part of these vibration prevention measures, methods of using vibration-proofing alloys, methods of laminating vibration-damping materials to metals, or composite vibration-damping materials in which polymer substances are sandwiched between metals have been used. Methods have been developed and are beginning to be adopted in a wide range of fields. In general, loss coefficient (η), logarithmic damping ratio (△), resonance sharpness (Q), etc. are used as measures of the vibration damping effect of damping materials such as damping steel plates.
These are mutually related physical property values. Among these physical property values, the loss coefficient (η) is the most commonly used. Conventionally, it was said that if η is 0.05 or more, the vibration damping effect is large, but due to the recent tightening of noise regulations, it has become clear that η is even larger. The development of vibration damping materials is expected. An object of the present invention is to provide a vibration damping material that has a larger loss coefficient (η) than the trends of the times and has excellent workability. The gist of the present invention is as follows.
That is, in a composite vibration damping laminate comprising a polymer material layer and a metal layer that have damping performance against metal, the polymer material is (A) polyvinyl acetal resin and (B) polyalkylene. Isophthalate・
This is a composite damping laminate characterized in that it is a substance containing a component consisting of terephthalate and (C) a plasticizer in some cases. Composite vibration damping materials generally have a polymer substance sandwiched between metals such as steel plates, so η changes depending on the operating temperature, and η has the property of reaching a peak at a certain temperature. ing. Therefore, it is necessary to select a polymer material that is compatible with the intended use temperature, but the inventors' research has shown that the temperature at which the loss coefficient (η) is maximized can be changed by changing plasticizers and additives. It was confirmed that this is possible. However, as a damping material, such temperature dependence is small η
Of course, the higher the value, the better. It is generally believed that the higher the loss tangent (tan δ) of the polymeric substance used to improve the vibration damping properties of a laminate such as a composite damping laminated steel plate, the better. Another aspect of the composite vibration damping laminate is a non-constrained vibration damping laminate. This is a laminate in which a polymer material with excellent vibration damping performance is bonded to a metal such as a steel plate, and exists as a free layer. Generally, polymer materials with a high complex modulus of elasticity (E'') are preferred. Recently, restrained type vibration damping laminates that contain less resin and have excellent vibration damping properties have been attracting attention.The present invention will be explained in detail below. As a result of intensive research into high molecular weight substances, a patent application was filed in 1982.
It has been found that the polyvinyl acetal resin shown in No.-228277 is effective. Although the resin according to the invention has excellent vibration damping properties, it has some difficulties in the temperature dependence of the loss coefficient η, and the temperature range in which it exhibits effective vibration damping properties is narrow. The inventors of the present invention have made extensive studies to improve this drawback, and as a result have arrived at the present invention. That is, the gist of the present invention is that by adding (B) polyalkylene isophthalate/terephthalate to (A) polyvinyl acetal resin, η decreases little and η
The present invention has been accomplished by discovering a method that has little dependence on temperature, that is, has a broad peak, and is industrially very valuable. It is also possible to arbitrarily control the peak of η by controlling the amount of the polyalkylene isophthalate/terephthalate copolymer resin. It is also possible to add (C) a plasticizer for the purpose of lowering the peak temperature (temperature showing the maximum loss coefficient). Additionally, polyvinyl acetal resin easily crosslinks when heated and is difficult to handle in a molten state, but by adding polyalkylene isophthalate/terephthalate copolymer, the crosslinkability is alleviated, making it easier to handle industrially. is unpredictable and highly beneficial. Polyvinyl acetal resin, which is component (A) of the polymer used in the present invention, is produced from vinyl acetate, aldehyde, etc. Generally, vinyl acetate monomer is polymerized to produce polyvinyl acetate resin, and then saponified. It is produced by the reaction of the polyvinyl alcohol obtained by the above method with an aldehyde. That is, the polyvinyl acetal resin component is a copolymer resin having vinyl acetal groups, vinyl alcohol groups, and vinyl acetate groups, and the reaction product of this resin with formaldehyde is called formal resin, and the reaction product with butyraldehyde is called butyral. It is called resin. The average degree of polymerization of the polyvinyl acetal resin used in the present invention is preferably in the range of 300 to 5000, and the higher the degree of polymerization, the more preferable it is. Further, the degree of acetalization is preferably about 50 to 85 mol%. Examples of the polyvinyl acetal resin include polyvinyl butyral, polyvinyl formal, polyvinyl acetoacetal, and polyvinyl propyl acetal, among which polyvinyl butyral resin or polyvinyl formal resin is preferably used. Furthermore, polyvinyl acetal resins containing carboxyl groups are also preferably used. It is preferable that the carboxyl group is contained in the polyvinyl acetal resin in an amount of about 0.1 to 5 mol%, preferably about 0.2 to 3 mol%. As polyvinyl acetal resin containing a carboxyl group, for example, a method of producing polyvinyl acetal resin by a conventional method using a copolymer of vinyl acetate and an unsaturated carboxylic acid, or a method of acetalizing polyvinyl alcohol. It is obtained by reacting with an aldehyde containing a carboxyl group. The polyalkylene isophthalate/terephthalate copolymer, which is the component (B) of the polymer targeted by the present invention, is produced by melt polymerization of dimethyl terephthalate, dimethyl isophthalate, and a glycol component using, for example, antimony trioxide as a catalyst. Copolymers of various compositions can be produced. The content of isophthalic acid component is 5 to 5% of the total acid component.
40 mol% is suitable. There is no particular limitation on the intrinsic viscosity, but it may be within the range of 0.5 to 0.9 dl/g. Glycol components include ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, and propane.
1,3-diol, butane-1,4-diol,
Polytetramethylene glycol, 1,4-hydroxymethylcyclohexane neopentyl glycol, etc. are used. Particularly preferred are those containing ethylene glycol as a main component, and it goes without saying that ethylene glycol and other glycol components such as neopentyl glycol may be combined. The mixing composition ratio of the polyvinyl acetal resin and the polyalkylene isophthalate/terephthalate copolymer may be in the range of 10 to 90% by weight to 90 to 10% by weight. For example, if the composition ratio is less than 10% by weight of polyvinyl acetal resin, the damping properties of the polyalkylene isophthalate/terephthalate resin will dominate, and if it exceeds 90%, the damping properties will be dominated by the polyvinyl acetal resin, and there will be no effect of mixing the two. . Also, in order to adjust the temperature range where the maximum value of η is obtained,
An effective method is to add a plasticizer as component (C).
The amount added preferably does not exceed 40 parts by weight based on the total of 100 parts by weight of components (A) and (B). If it exceeds 40 parts by weight, it is not preferable because it leads to a decrease in adhesive strength to metal surfaces and a decrease in the absolute value of η. Examples of plasticizers that can be added include phthalic acid esters such as dibutyl phthalate, dioctyl phthalate, and butylbenzyl phthalate, phosphoric acid esters such as tricresyl phosphate, dibutyl sebacate, di-2-ethylhexyl adipate, and dibutyl succinate. Fatty acid esters, glycol derivatives such as triethylene glycol dibutyrate, vegetable oils such as soybean oil, linseed oil, and castor oil, and epoxidized products thereof are generally used, and in the present invention, any one of these may be used. You can choose. The role of the plasticizer is as described above, but generally, as the amount of plasticizer added increases, the maximum value of the loss coefficient (η) shifts to a lower temperature range. Furthermore, an inorganic filler can be added for the purpose of improving the elastic modulus, adhesiveness, etc. of the polymer composition. Examples include scaly graphite, mica, conductive carbon black, carbon graphite, talc, and magnesium carbonate. The amount added is about 10 to 100 parts by weight, preferably about 20 to 50 parts by weight, based on a total of 100 parts by weight of components (A) and (B). Next, metals used in the laminate according to the present invention will be explained. The metal plate used in the present invention has adhesive properties with the polymeric substance used as an intervening body,
Although a steel plate is most suitable in terms of strength, cost, etc., other metal plates such as copper plates and aluminum plates can also be used. The steel plates include surface-treated steel plates such as mild steel plates, high-strength steel plates, stainless steel plates, and galvanized steel plates, or those coated with surface-treated steel plates such as phosphate or chromate treatment, which are commonly used for preliminary treatment of metal surfaces. Steel plates with surface treatment can also be used depending on the purpose of use. The surface of these steel plates should be clean in order to obtain the best adhesion with the viscoelastic polymeric material, and for this purpose sandblasting or the like may be necessary in some cases. These steel plates may be used as flat plates, but they may also be subjected to bending or drawing depending on the shape of the desired laminate. In addition, the steel plates used as vibration-damping laminates are heated during the manufacturing process, so if a steel plate that ages easily is used, a surface distortion pattern called stretch strain will occur during processing, which will impair the appearance. If the appearance after processing is important, the aging index (AI) is 1.5Kgf/mm ²
The following non-aging steel plates should be used: In order to manufacture such a damping laminate, for example, a so-called pressing method is used in which a metal plate and a polymer material layer are laminated and heated and pressed to a temperature higher than the melting point of the polymer material layer, or two metal plates are An extrusion lamination method in which a polymer material extruded in a sheet form in a molten state from an extruder is fed between metal plates and laminated while being fed into a roll.
A coating and lamination method in which a polymer substance is dissolved in a solvent, this is applied to a metal plate, the polymer substance is melted while the solvent is evaporated by heating, and then a metal plate is laminated by pressing on the polymer substance layer. Any method can be used. Various shapes and thicknesses of metal plates are used depending on the intended product, but generally speaking, for example, a three-layer structure in which a polymer material layer is interposed between two metal plates is used. Metal plate is 0.01
It is sufficient that the polymer material layer has a thickness of 1/20 or more of the metal plate with a thickness of mm or more. Although the thickness of the metal plate is usually the same on both sides, it may be different depending on the use, and it is also possible to form a laminate of three or more layers depending on the use. The temperature dependence of the loss coefficient η of the vibration-damping laminate can be obtained by setting the test material in a thermostatic chamber, setting it at various temperatures, changing the frequency, and calculating the loss coefficient from the sharpness of the resonance point of the mechanical impedance. Ta. The damping properties were judged firstly in the temperature range where the absolute value of η was 0.1 or more, and secondly in the temperature range where the absolute value of η was 0.3 or more. Example 1 A normal cold-rolled steel plate of 0.6 mm x 250 mm x 250 mm was degreased with trichlorene and used as a metal base material for a laminate according to the present invention. The aging index of the steel plate was 0 kgf/mm ² . Next, 55% by weight polybutyral resin with a degree of polymerization of 1050 and a degree of butyralization of 81%, and 10 dioctyl phthalate.
Intrinsic viscosity at wt%, isophthalic acid content 12 mol%
35% by weight of a 0.68% polyethylene isophthalate/terephthalate copolymer was thoroughly mixed and melt-kneaded at 230°C in a 40 mm diameter single screw extruder to form pellets. 300% by using a 100 ton heat press using the pellets.
A sheet measuring mm×300 mm and 110μ thick was obtained. . The sheet was sandwiched between the two steel plates mentioned above, preheated and defoamed at 230°C for 3 minutes using a hot press, and then crimped under heat and pressure for another 3 minutes to form a composite mold with a thickness of 1.3 mm. A shake laminate was obtained. The temperature dependence of the loss coefficient η of the composite damping laminate thus obtained is shown in Figure 1A. Example 2 Using the same raw materials as in Example 1, 68% by weight of polyvinyl butyral, 12% by weight of dioctyl phthalate, and 20% by weight of polyethylene isophthalate/terephthalate copolymer were pelletized in the same manner as in Example 1. A composite damping laminate was obtained. The temperature dependence of η is shown in Figure 1B. Comparative Example 1 Using the same raw materials as in Example 1, 85% by weight of polyvinyl butyral and 15% by weight of dioctyl phthalate, a composite damping laminate was obtained after pelletizing in the same manner as in Example 1. The temperature dependence of η is shown in Figure 1C. Comparative Example 2 A composite damping laminate was obtained by pelletizing the polyethylene isophthalate/terephthalate copolymer, which was the same raw material as in Example 1, in the same manner as in Example 1. The temperature dependence of η is shown in Figure 1D. In Figure 1, the temperature range of η0.1 or higher and the temperature range of 0.3 or higher are summarized in Table 2.

[Table] Example 3 Example-1 except that polyvinyl formal with a degree of polymerization of 930 and a degree of formalization of 86% was used instead of polyvinyl butyral in Example 1, and butylbenzyl phthalate was used instead of the plasticizer dioctyl phthalate. A composite damping laminate was obtained in the same manner as above. The maximum value of loss coefficient (η _nax ) was 0.49, and the temperature at this time was 98°C.

[Brief explanation of the drawing]

Figure 1 is a graph showing the temperature dependence of the loss coefficient η of a composite damping laminate. In the figure, A to D indicate the case of the laminates of Examples 1 and 2 and Comparative Examples 1 and 2, respectively.

Claims (1)

[Scope of Claims] 1. A composite vibration damping laminate comprising a polymer material layer and a metal layer that provide vibration damping performance for metal, wherein the polymer material is (A) polyvinyl acetal resin 10~ 90% by weight (B) 90 to 10% by weight of polyalkylene isophthalate/terephthalate copolymer resin, and optionally (C), based on the total of 100 parts by weight of components (A) and (B) A vibration damping laminate comprising 40 parts by weight or less of a plasticizer. 2. The laminate according to claim 1, wherein the polyvinyl acetal resin is a polyvinyl butyral resin or a polyvinyl formal resin. 3. The laminate according to claim 1 or 2, wherein the polyalkylene isophthalate/terephthalate copolymer resin has an intrinsic viscosity of 0.5 to 0.9 dl/g and an isophthalic acid component content of 5 to 40 mol%. . 4. The laminate according to any one of claims 1 to 3, wherein the metal is a steel plate.