JPS6097842A - Vibration-damping sound-insulating method of metallic plate - 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 and soundproofing method for a metal plate, and its main purpose is to suppress the vibration of a metal plate by using a lightweight foamed resin layer, and also to suppress the vibration of a solid material accompanying the vibration.

It is an object of the present invention to provide the above-mentioned vibration damping and soundproofing method which prevents noise and improves the uniformity of thickness and adhesion of the foamed resin layer.

Conventionally, as a means to prevent the vibration of metal plates used in vehicles such as automobiles and electrical equipment, and the solid sound induced by this, methods such as making the metal plate itself thicker or lining it with steel material, etc. A method of providing a layer of vibration-damping and sound-insulating material is adopted.

The former method aims to reduce the vibration speed by increasing the mass and rigidity of the metal plate, but it has the disadvantage of increasing the weight of the system containing the metal plate, making it particularly difficult to reduce the weight of automobile outer panels. Unsuitable for the required use.

On the other hand, the latter method forms a vibration-damping and sound-insulating layer by coating a liquid or fluid material or pasting a sheet material, and utilizes the vibration-damping and sound-insulating effects of the layer itself. Such vibration damping and soundproofing effects are generally achieved by increasing the vibration loss coefficient (loss
It is said that materials with η of 0.05 or more can be used for vibration damping and soundproofing. However, with the coating method described above, it is difficult to make the thickness of the coating layer uniform, requiring skill in the coating process, and it takes a long time to dry, resulting in poor construction efficiency. . In addition, sheet materials that utilize the viscoelasticity and flexibility of polymers, such as rubber or asphalt with a high specific gravity, have difficulty forming the sheet material, and are unable to be rolled into a tape shape or easily lose their shape. However, when a polymer containing a large amount of inorganic powder was used to increase mechanical hysteresis and internal friction, the adhesion to a metal plate was poor.

As a result of intensive research in view of the above-mentioned situation, the inventors used a hard plate and a foamed heat-adhesive sheet, adhered the sheet to a metal plate with the hard plates laminated, and heated it. The inventors have discovered that by foaming, it is possible to form an ideal vibration-damping and sound-insulating layer without the above-mentioned conventional drawbacks, leading to the creation of this invention.

That is, this invention heats a hard plate by bringing it into contact with the surface of a metal plate via a foamable heat-sealing sheet made of a thermoplastic resin containing a foaming agent, and then laminating the hard plate on the surface of the metal plate. The present invention relates to a vibration damping and soundproofing method for a metal plate, which comprises forming a foamed resin layer.

In this invention, the loss coefficient η of the thermoplastic resin foam laminated with hard plates that serve as a vibration damping and sound insulating layer on the surface of the metal plate varies greatly depending on the foaming ratio (although it generally falls within the range of 0.08 to 1.0). Therefore, the foam has properties for vibration damping and sound insulation.However, a mere foamable heat-sealing sheet is prone to thermal deformation during heating and foaming, and this deformation can cause the thickness of the vibration damping and sound insulation layer to be uneven. There is a problem that the vibration damping and soundproofing effect is inferior because the adhesion with the metal plate deteriorates as the thickness increases.

In this invention, the hard plate laminated on one side of the foamable heat-adhesive sheet has the function of suppressing the above-mentioned thermal deformation, and its presence makes the thickness of the vibration-damping and sound-insulating layer uniform and has good adhesion to the metal plate. In addition, the vibration damping and soundproofing effects themselves are improved.

In addition, if a method other than the above-mentioned invention is used, such as heat-sealing a pre-fabricated foam sheet to a metal plate without using a foamable heat-sealable sheet, the bubbles of the foam may collapse. This is not practical because the vibration damping and soundproofing effect is lost.

Examples of the thermoplastic resin for the foamable heat-adhesive sheet used in this invention include polyethylene, ethylene-vinyl acetate copolymer, polypropylene, and polyvinyl chloride.

Examples of blowing agents to be added to such thermoplastic resins include azo compounds such as azodicarbonamide and azobisisobutyronitrile, nitroso compounds such as dinitrosopentamethylenetetramine, paratoluenesulfonyl hydrazide, and 4-oxybisbenzenesulfonyl hydrazide. These may be used alone or in combination of two or more, and if necessary, urea,
Foaming aids such as carboxylic acid metal salts may also be added.

It should be noted that these foaming agents are selected to be those that decompose at a temperature higher than the softening temperature of the resin in which they are blended and generate gas, and that do not foam or foam slightly during sheet molding.

The amount of foaming agent to be used is preferably within the range that produces closed cells at a foaming ratio of about 5 to 20 times; if the amount used is too small, it will not substantially function as a foam, and if it is too large, open cells will be formed, and neither of these will be controlled. Vibration and soundproofing effect decreases.

In this invention, a foaming agent, a foaming aid blended as desired, a crosslinking agent, a filler, a coloring agent, an anti-aging agent, etc. are added to the thermoplastic resin, and the mixture is kneaded with a mixing roll or the like and foamed. A thermoplastic resin composition is prepared and molded into a sheet to obtain a foamable heat-sealing sheet. As a means for this, the foamable resin composition is pelletized in advance using a pelletizer, and the pellets are extruded into a sheet shape using an extrusion molding machine under molding temperature conditions that do not substantially decompose the foaming agent, or the above-mentioned composition is The product can be directly formed into a sheet by calender molding or hot pressing. The foamable heat-sealable sheet formed in this way varies depending on the type of metal plate to be vibration-damped and sound-proofed, but usually has a 0.1 to 8
It is preferable to have a thickness of about mm.

Among the foamable heat-sealable sheets obtained as described above, those using polyethylene as the thermoplastic resin and 4,4'-oxybisbenzenesulfonyl hydrazide as the blowing agent are particularly preferred.

Examples of the hard plate used in this invention include metal plates and plastic plates. The material of this metal plate is
It may be made of steel, aluminum, plated steel plate, or any other material. The thickness of this metal plate varies depending on the type and shape of the metal plate to be vibration-damped and sound-proofed, but it is usually 0.
．． It is preferable to set it to about 0.05 to 1 mm.

Further, the plastic plate may be made of either thermoplastic resin or thermosetting resin, but it is preferable to use one formed of these resins with a reinforcing material embedded therein. Examples of the thermoplastic resin include polyethylene, ethylene-vinyl acetate copolymer, polypropylene,
Examples include polystyrene and polyvinyl chloride. Further, the thermosetting resin is not particularly limited as long as it is generally used for reinforced plastics.

Examples of the reinforcing material include cheesecloth, coarse sheets of various materials, woven fabrics or non-woven fabrics. The thickness of this plastic plate varies depending on the type of metal plate to be vibration-damped and sound-proofed, but it is usually about 0.1 to 1 mm.

Among such plastic plates, one in which glass fiber cloth is used as a reinforcing material and is impregnated with polyethylene or polyester is particularly preferable.

In order to perform vibration damping and soundproofing of a metal plate using the above-mentioned foamable heat-adhesive sheet and hard plate, it is usually preferable to laminate and integrate the heat-adhesive sheet and the hard plate. To integrate these, a pressure-sensitive adhesive may be used, or a hard plate may be pressed onto one side of the sheet and heat pressed, or the hard plates may be laminated by passing them between heated rolls. Although this is common, a method of extruding and integrating the foamable resin composition onto a hard plate may also be used.

Next, as shown in FIG. 1, a laminate 3 consisting of the heat sealing sheet 1 and the hard plate 2 is heated to a temperature higher than the softening temperature of the thermoplastic resin component contained in the heat sealing sheet 1. It is pressed onto the surface of the metal plate 4 to be attached, with the surface on the heat-sealing sheet 1 side serving as the adhesion surface. As a result, the thermoplastic resin component of the sheet 1 starts to soften and flow, causing the laminate 8 to move against the metal plate 4.
temporary adhesion is done. By successively heating the sheet 1, the sheet 1 foams, and as shown in FIG.
At the same time as the foamed resin layer 1' is formed, the laminate 30 is strongly bonded.

In addition, when the metal plate 4 is an outer panel for an automobile, the above-mentioned laminate 8 is applied to the surface of the metal plate 4 opposite to the painted surface in the painting process.
If the foamable heat-adhesive sheet 1 is used as the adhesive surface and the sheet 1 is heated and foamed and adhered at the same time using the heat during painting, the efficiency of thermal energy use will increase, and the Construction time in the manufacturing process can be shortened.

On the other hand, in order to temporarily bond the laminate 3 to the metal plate 4 via the foamable heat-sealing sheet 1, there is a method other than preheating the metal plate 4 as described above. Even if a configuration is adopted in which a pressure-sensitive adhesive is provided in advance on the side opposite to the side where the metal plate 4 is attached, and the adhesive force of this adhesive layer is used to temporarily adhere. good. This embodiment is particularly effective when the resin component of the heat sealing sheet 1 is polyethylene or the like. In this case, the metal plate 4 may be preheated in parallel.

Hard plate 2 formed on the surface of metal plate 40 as described above
The foamed resin layer 1' on which the resin is laminated has a uniform thickness because the hard plate 2 prevents elongation and distortion during temporary adhesion and heat foaming, as well as distortion caused by cooling and solidification. Excellent adhesion to the surface of the plate 4,
The appearance is also good. And such a foamed resin layer 1 is
When vibration is applied to the metal plate 4, the contraction and deformation of the bubbles, the elasticity of the entire layer, and the presence of the hard plate 2 absorb and suppress the bending vibration of the metal plate 4, thereby preventing the generation of solid sound. It functions as an excellent vibration damping and sound insulating layer.

Note that the above method describes the case of using a laminate in which the foamable heat-adhesive sheet and the hard plate are laminated and integrated in advance, but instead of using such a laminate, the surface of the metal plate is It is also possible to laminate a heat-sealable sheet and a hard plate so that the hard plate and this sheet become integrated when the sheet is heated and foamed.

Hereinafter, this invention will be specifically illustrated by examples.

Example 1 Polyethylene (Sumi Rikisen G-801 manufactured by Sumitomo Chemical Co., Ltd.)
100 parts by weight, 4,4'-oxybisbenzenesulfonyl hydrazide (Neocellvon FE, a blowing agent manufactured by Hydraulic Chemical Co., Ltd.)
-9) After kneading 8 parts by weight with a mixing roll,
The pellets were pelletized using a pelletizer, and the pellets were put into an extrusion molding machine and extrusion molded at an extrusion temperature of 115°C to obtain a foamable heat-adhesive sheet with a thickness of 0.5 mm.

Glass fiber cloth (WE manufactured by Nittobo Co., Ltd.) was coated on one side of this sheet.
-22D-104, density 21 OS'/m2) impregnated with polyethylene (Sumikasen L-705 manufactured by Sumitomo Chemical Co., Ltd.) and 0.5 mm thick reinforced polyethylene plate is pressed with a hot press to form a laminate, Length 150mm, width 80mm
It was cut into

On the other hand, a cold-rolled steel plate with a thickness of 0.8 mm, a length of 200 mm, and a width of 80 mm was preheated to 160°C, and the above-mentioned laminate was pressure-bonded to the surface of the cold-rolled steel plate with the foamable heat-sealing sheet side as the attachment surface.
After continued heating at 60°C for 20 minutes to foam,
The reinforced polyethylene plates were laminated to form a foamed resin layer having a uniform thickness of about 4.5 mm. The foaming ratio of this foamed resin layer was about 8 times, and the adhesion between the steel plate and the foamed resin layer was good.

Example 2 A foamed resin layer in which a reinforced polyester plate was laminated on a cold rolled steel plate was formed in the same manner as in Example 1 except that a glass fiber reinforced polyester plate with a thickness of 0.5 mm was used instead of the reinforced polyethylene plate. . The thickness of this foamed resin layer is approximately 4.
The thickness was uniform at 5 mm, and the expansion ratio was approximately 8 times. Furthermore, the adhesion between the steel plate and the foamed resin layer was also good.

Example 3 A foamed resin layer with aluminum plates laminated on a cold-rolled steel plate was formed in the same manner as in Example 1, except that an aluminum plate with a thickness of 0.8 mm was used instead of the reinforced polyethylene plate. This foamed resin layer had a uniform thickness of about 4 mm, and the foaming ratio was about 8 times.

Furthermore, the adhesion between the steel plate and the foamed resin layer was good.

Comparative Example A foamed resin layer was formed in the same manner as in Example 1, except that the reinforcing polyethylene plate was not laminated on the foamable heat-sealable sheet. This foamed resin layer had an uneven thickness and the entire outer surface was uneven.

The sample steel plates obtained in Examples 1 to 3 and Comparative Example were subjected to sinusoidal electromagnetic excitation, and the resonance wave number and the loss coefficient after the excitation was stopped were determined. The results are shown in the table below along with the similar test results for the steel plate alone.

From the results shown in the above table, it is clear that the method of the present invention can provide excellent vibration damping and soundproofing effects to metal plates.

In addition, in this invention, the foamable heat-sealing sheet is heated and foamed with the hard plates laminated, so the foamed resin layer formed has a uniform thickness and has good adhesion to the metal plate. Because it is extremely lightweight, even if hard plates are laminated, the weight increase due to this adhesion is extremely small, making it highly applicable to applications that require weight reduction, such as automobile outer panels. ing.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a state in which a laminate made of a hard plate and a foamable heat-adhesive sheet according to the present invention is adhered to a metal plate, and FIG. It is a diagram. ■...Foamable heat-adhesive sheet, 2...Hard board, 4...
- Metal plate, 1... foamed resin layer. Patent applicant: Nitto Electric Industry Co., Ltd. Figure 1 Figure 2 257

Claims (4)

[Claims] (1) A hard plate is brought into contact with the surface of the metal plate to be vibration-damped and sound-proofed through a foamable heat-adhesive sheet made of a thermoplastic resin containing a foaming agent, and heated. A vibration damping and soundproofing method for a metal plate, characterized by forming a foamed resin layer in which plates are laminated. (2) The vibration damping and soundproofing method for a metal plate according to claim (1), wherein the thermoplastic resin in the foamable heat-sealable sheet is polyethylene, and the foaming agent is 4,4'-oxybisbenzenesulfonyl hydrazide. . (3) The foamable heat-sealing sheet has a pressure-sensitive adhesive layer on the side opposite to the side on which it is laminated with the hard plate (the side to be adhered to the surface of the metal plate). Paragraph 1) or Paragraph (2)
Vibration damping and soundproofing method for metal plates as described in . (4) Claims Nos. (1) to 1, in which the hard plate is a metal plate.
(3) The vibration damping and soundproofing method for a metal plate according to any one of paragraphs. +51 The vibration damping and soundproofing method for a metal plate according to any one of claims (1) to (3), wherein the hard plate is a plastic plate with a reinforcing material embedded therein.