JPH0292540A - Vibration damping composite structural body and its manufacture - Google Patents

Abstract

PURPOSE:To improve vibration damping/soundproof functions by forming a structural body singly with synthetic resin, by specifying a combination of resin by making use of a melt press molding method. CONSTITUTION:The whole resin which can perform melt press molding can be used for synthetic resin B constituting an outer layer. It is necessary that the maximum value of tan delta of synthetic resin (A) becoming a principal constituent material of an intermediate layer is at least 0.2 and the synthetic resin (A) has the low modulus of elasticity as compared with the modulus of elasticity of the synthetic resin (B) constituting an outer layer at 25 deg.C. A copolymer, for example, of ethylene and vinyl acetate, vinyl chloride, acrylic acid or acrylic acid derivative and methacrylic acid or methacrylic acid derivative is available as the synthetic resin (A) like this. It is necessary to mold with a melt press molding method to obtain a vibration damping composite structural body with a sheet having the synthetic resin (A) for its main constituent material and the synthetic resin (B). A sandwich injection molding method is available as a method to obtain a vibration damping composite structural body.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to gear case covers for automobiles, motorcycles, etc.
Excellent vibration-damping acoustics for use in noise-generating areas such as air cleaner cases and radiator fans, household appliances such as washing machines and vacuum cleaners, and office equipment such as word processors and personal computer printers. The present invention relates to a synthetic resin structure having high performance and a method for manufacturing the same.

[Prior art]

Conventionally, as a means of preventing vibration and noise, research and development of vibration-absorbing materials in which the material itself has vibration-absorbing ability has been advanced, and vibration-damping materials with high vibration-absorbing performance and suitable for applications are being developed for vehicles, ships, and industries. It is used as a structural member for machinery, iron bridges, etc.

Conventionally, such damping materials include vinyl acetate-ethyl acrylate copolymer (Japanese Patent Publication No. 45-35662), a copolymer obtained by grafting a mixture of styrene and acrylonitrile onto vinyl acetate-ethylene copolymer (Japanese Patent Publication No. 45-35662), Publication No. 46-17064), resin compositions based on carboxylic acid-modified polyolefin resins (Japanese Patent Application Laid-open No. 59-804)
Laminated structures with a composition such as No. 54) as an intermediate layer, and materials in which filler such as calcium carbonate is added to bitumen are known.

[Problem to be solved by the invention]

However, these compositions generally have a low modulus of elasticity, making it difficult to obtain a structure by themselves, requiring them to be bonded to a base material such as a steel plate, and having drawbacks such as poor heat resistance.

The present invention was made in order to solve the problems of the prior art, and relates to a molded product that can form a structure solely from a synthetic resin and has excellent vibration damping and soundproofing functions, and a method for easily obtaining the molded product. be.

[Means to solve the problem]

The present invention uses a melt press molding method as a means to solve the conventional problems mentioned above, and also devises a combination of resins. More specifically, (1) A synthetic resin [A] which is a structure of two types and three or more layers, and whose intermediate layer has a maximum value of tan δ of 0.2 or more in the temperature range of -50'C to 50°C. A synthetic resin (B) whose elastic modulus at 25°C is greater than or equal to the elastic modulus of the synthetic resin [A] is used as the outer layer, and is obtained by a melt press molding method. Characteristic vibration damping composite structure, (2) tan δ in the temperature range of -50°C to 50°C
After installing a sheet whose main constituent material is synthetic resin [A] with a maximum value of 0.2 or more in a mold, The present invention relates to a method for producing a vibration-damping composite structure, which is characterized in that synthetic resin [B] is formed by melt press molding on both sides of a sheet whose main constituent material is synthetic resin [A].

As the synthetic resin [B] constituting the outer layer, any resin that can be melt press-molded can be used, but among them, polypropylene resin, polyamide resin, which has a high elastic modulus at room temperature and is relatively easy to mold, polyethylene resin, poly-4-methyl-1-pentene resin, polystyrene resin,
Acrylonitrile-styrene resin, acrylonitrile-styrene resin, polycarbonate resin,
Polyethylene terephthalate resin, polybutylene terephthalate resin, polyacetal resin, polyphenylene oxide resin, etc. are suitable.

Moreover, a composite compound in which fillers such as calcium carbonate, talc, mica, and glass fiber are mixed is even more suitable.

Next, the synthetic resin [A] which is the main constituent material of the intermediate layer has a maximum value of tan δ of 0.2 or more in the temperature range of -50°C to 50''C, and the synthetic resin CB which forms the outer layer ) is required to have a lower elastic modulus than the elastic modulus at 25°C.

Maximum values of ta and nδ of synthetic resin [A] are 150°C to 5
When the value is less than 0.2 in the temperature range of 0° C., good vibration damping performance cannot be exhibited in the temperature range where the damping material is normally used, that is, at room temperature and the temperature range around it.

Examples of such synthetic resins [A] include copolymers of ethylene and vinyl acetate, vinyl chloride, acrylic acid or acrylic acid derivatives, methacrylic acid or methacrylic acid derivatives, and specifically ethylene-vinyl acetate copolymers. Union,
Ethylene-acrylic acid copolymer, ethylene-ethyl acrylate copolymer, ethylene-methyl methacrylate copolymer, ethylene-ethyl acrylate-maleic anhydride copolymer, ethylene-vinyl acetate-glycidyl methacrylate copolymer, ethylene-acetic acid Vinyl-hinyl chloride co-m combination s can be mentioned. In addition, copolymers of vinyl acetate and acrylic acid or acrylic acid derivatives that do not contain ethylene can be used, such as vinyl acetate-methyl acrylate copolymers and the like.

Thermoplastic high molecular weight polyester resins are also preferred, and among these, non-grade thermoplastic high molecular weight polyester resins having a glass transition of 1M degrees in the temperature range of 0°C to 60°C are more preferred.

Also preferred is a thermoplastic polyester resin having a structure in which a component having rubber elasticity (soft segment) and a component having thermoplastic ability (hard segment) are combined and modified in the molecule.

This structural classification is as follows: (i) a type in which a soft part and a hard part are arranged in a bronch-like manner in one molecule, and (iii) a type in which a soft part and a hard part are grafted together. There is a type (iv) in which the soft part is partially cross-linked and a type in which the hard part has an ionically cross-linked structure.

The sheet whose main constituent material is synthetic resin [A] constituting the intermediate layer may be a sheet formed into a specific shape other than a flat sheet, or it may be a single layer made of synthetic resin [A]. Synthetic resin [A]
It may also be a multi-layer sheet containing a sheet consisting of as one layer.

In the case of this multilayer sheet, in order to improve the adhesion between the synthetic resin [A] and the outer layer synthetic resin [B], the synthetic resin [Δ]
It is also possible to use a multilayer sheet, etc., in which an adhesive layer is provided on the layers consisting of the above, as the intermediate layer of the vibration damping composite structure of the present invention.

Alternatively, a multi-layered material having a needle penetration temperature higher than that of the synthetic resin [A], that is, a synthetic resin (C) having higher heat resistance than the synthetic resin [A] is provided on at least one side of the synthetic resin [A]. Sheets can also be used as intermediate layers. Instead of using such a synthetic resin (C) with high heat resistance, the synthetic resin [B] is directly placed on the sheet of synthetic resin [A].
] When melt-press molding the synthetic resin [A], the synthetic resin [A] may be significantly deformed.

In such a case, deformation of the intermediate layer sheet can be prevented by providing a synthetic resin (CC) with high heat resistance on at least one surface of the sheet of synthetic resin [A].

The needle penetration temperature here refers to the temperature measured by the following method: A needle-like indenter made of quartz with a circular cross section of 0.5 m is placed vertically on a film or sheet material. , a load of 20 g is applied through the indenter.

When the temperature of the material is increased at 10'C/min, the relationship between the displacement of the indenter and the temperature becomes a graph as shown in FIG. At this time, the temperature at the intersection E of the tangents AB and CD of the two trees shown in FIG. 6 is defined as the needle penetration temperature.

In order to obtain the vibration-damping composite structure of the present invention from a sheet mainly composed of synthetic resin [A] and synthetic resin [B], it is necessary to perform molding by a melt press molding method. Sand inch injection molding is one method for obtaining vibration damping composite structures.

In this case, after injecting the synthetic resin CB) constituting the outer layer to a volume less than the volume of the mold cavity, the synthetic resin [A] for the intermediate layer is injected.
However, it is difficult to make the thickness of the intermediate layer within the damping composite structure uniform, making it difficult to stably mold a damping composite structure with good damping performance. It is.

Another method for obtaining a vibration-damping composite structure is a multilayer extrusion method using synthetic resin [A] as an intermediate layer.

In this case, the thickness of the intermediate layer becomes relatively uniform, but this method is applicable only to relatively simple vibration-damping composite structures in the form of sheets, etc. If you use the melt press molding method invented by Riki, you can reduce the thickness of the intermediate layer to the required value, which is not suitable for molding complex-shaped vibration damping composite structures such as parts for electrical equipment and office equipment. It becomes possible to obtain a vibration-damping composite structure with a complex shape while maintaining the same.

The melt press molding method of the present invention involves placing a solid sheet mainly composed of synthetic resin [A] in a mold between a pair of press plates, and then applying a molten sheet to at least one surface of the sheet. This is a method of supplying synthetic resin CB) and further compressing a press plate to reduce the gap therebetween, thereby cooling and shaping the synthetic resin [B] to obtain a predetermined molded product. To obtain a vibration damping composite structure with high vibration damping properties, synthetic resin [A
] The main constituent material is synthetic resin [B] on both sides of the sheet.
An example of a melt press molding method in which synthetic resin [B] is preferably provided on both sides of the sheet is shown below with reference to the drawings.

(b) As shown in Figure 1, a sheet (7) whose main constituent material is synthetic resin [A], which has holes equivalent to or larger than the supply port (6) for molten synthetic resin [B], is R such that the periphery of (8) touches the periphery of the supply port (6).
W.

(b) From the supply port (6), pass the sheet (7) through the hole (8).
) The synthetic resin CB melted on the side opposite to the supply port) (9)
While supplying or immediately after supplying, press molding is performed as shown in FIG. 2 to shape the product.

(c) Maximize the gap between the upper and lower molds (2 and 4)! Upper or lower mold (2 or 4) until the gap is larger than the gap when shaping is completed.
After moving the molten synthetic resin [B
] (10) is supplied to the supply port side with respect to the sheet (7).

(d) While supplying synthetic resin [B] (10), or
Immediately after being supplied, the material is press-molded as shown in FIG. 4 for final shaping.

In this example, a hole (8) that is equal to or larger than the supply port (6) is provided in advance in the sheet (7), but if it is desirable that the sheet (7) does not have a hole (8), By using the upper mold (2) with the same structure as the lower mold (4), which has a resin passageway (5) and a supply port (6), no holes are formed in the sheet (7). A damping composite structure can be obtained.

〔Example〕

The present invention will be explained below with reference to Examples, but these are just examples and the present invention is not limited by these.

In the examples, the elastic modulus and tan δ of the synthetic resins [A] and [B] were measured using a Rheopyblon manufactured by Orientenk. The needle penetration temperatures of the synthetic resins [A] and (C) were measured using a thermal analysis measuring device (TMA-30) manufactured by Uozu Seisakusho.

The loss coefficient (η), which represents the vibration absorption ability of the material, is determined by forced vibration using the mechanical impedance method (center excitation) at a frequency of 1000.
Hz and temperature was measured at -20°C to 80°C.

Examples and Comparative Examples Ethylene-ethyl acrylate-maleic anhydride copolymer resin (manufactured by Sumika CDF Chemical, Bondine AX8390, needle penetration temperature 54°C) was used as the synthetic resin [A]. The synthetic resin (C) is a 100μ thick nylon film (made by Toshi, Rayfan [
F]No., needle penetration temperature: 216° C.) was laminated to obtain a sheet material for the intermediate layer.

As the synthetic resin for the outer layer (CB), a glass fiber reinforced nylon resin (manufactured by Toshi, Amiran CMIOIIG45, glass fiber 45 wt%) was used, and after melting it at 260 ° C.
1 to 4 on both sides of the sheet material for the intermediate layer.
A damping composite structure was obtained by melt press molding to the thickness of the pith.

The main physical properties of the synthetic resins [A] and [B] used are shown in Table 1, and the values of the loss coefficients of the obtained vibration damping composite structures are shown in Figure 5. , the loss coefficient of a molded article made of glass fiber reinforced nylon resin with the same shape is also shown.

By using the vibration damping composite structure of the present invention, the loss coefficient of the glass fiber reinforced nylon resin was improved and the vibration damping properties were significantly improved.

Table 1

[Brief explanation of drawings]

1 to 4 are cross-sectional views illustrating the present invention in detail. Figure 5 shows the vibration damping composite structure of the example and the 100 vibration damping composite structure of the comparative example.
It is a graph showing the temperature dependence of the loss coefficient at 0 Hz. FIG. 6 is a graph showing the relationship between displacement of the needle indenter and temperature. 1. Upper platen 2, upper mold 3, lower platen 4, lower mold 5, resin passage 6, supply port A, sheet 8 whose main constituent material is synthetic resin [A], hole in intermediate layer 9.10. Melted synthetic resin [B] 11.12. Synthetic resin after cooling and solidification [B] 13.14.
The temperature dependence of the loss coefficient of the structures of Examples and Comparative Examples is shown, respectively. (Margin below) Temperature (°C) Fig. 3 3 G'L4r54

Claims (2)

[Claims] (1) A structure with two or more types and three or more layers, in which the main constituent material is a synthetic resin [A] with a maximum value of tan δ of 0.2 or more in the temperature range of -50°C to 50°C as the intermediate layer. A vibration damping method characterized by using a synthetic resin [B] having an elastic modulus at 25° C. or higher than that of the synthetic resin [A] as the outer layer, and obtained by a melt press molding method. Composite structure. (2) After installing a sheet made of synthetic resin [A] whose main constituent material is a synthetic resin [A] with a maximum value of tan δ of 0.2 or more in the temperature range of -50°C to 50°C, the elastic modulus at 25°C A method for producing a vibration-damping composite structure, characterized in that a synthetic resin [B] having a modulus of elasticity greater than or equal to that of the synthetic resin [A] is formed on both sides of the sheet by melt press molding.