JPS6220542A - Vibration-damping sheet - Google Patents

Abstract

PURPOSE:To obtain a sheet improved in vibration-damping performance with outstanding workability, etc., for use in vehicle floor surface, by forming with a material prepared by incorporating specific matrix with each specified amount of thermosetting resin, tackifier, and inorganic filler. CONSTITUTION:The objective sheet can be obtained by incorporating (A) 100pts. wt. of a matrix comprising A1: 20-80pts.wt. of a rubber component (e.g., NR, NBR) and A2: 80-20pts.wt. of bituminous component (e.g., straight asphalt) with (B) 10-100pts.wt. of a thermosetting resin co-crosslinkable with the component A1 (e.g., unsaturated polyester), (C) 10-150pts.wt. of a tackifier (e.g., petroleum-based hydrocarbon resin, cumarone-based resin), and (D) 50-500pts.wt. of at least one kind of inorganic filler (e.g., silicon compound consisting mainly of SiO2, calcium carbonate) followed by kneading and extruding into a sheet 2-6mm thick.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a vibration damping sheet for attenuating vibrations by being attached to a metal base that generates vibrations on the floor of a vehicle.

<Prior art> Conventionally, damping of vehicle floors, etc. has been done by mixing various rubber components or bitumen with them and then extruding them to form a damping sheet, and after setting the damping sheet on the floor, it is heated and softened. , along with the floor surface and fused.

However, these damping sheets have difficulty achieving sufficient damping performance (especially at high temperatures), so damping sheets made by integrating rubber, a specific amount of thermosetting resin, and a specific inorganic substance (inorganic filler) are used. A seat has been proposed (Special Publication Act, 1986-9)
(See Publication No. 746) (Problems to be Solved by the Invention) However, as a result of the inventors' study of the above-mentioned vibration damping sheet, they found the following problems.

(a) In order to obtain a sufficient vibration damping effect, it is necessary to blend a large amount of inorganic filler, but if a large amount of inorganic filler is blended, workability (kneadability, extrusion moldability, etc.) decreases.

(b) If the thermal fluidization during heat treatment is insufficient, and the vibration sheet does not have sufficient followability (conformity) to the uneven shape of the vehicle floor surface, or if it does not fully conform to the vehicle floor surface, A gap is created between the vibration damping sheet and the vibration damping performance is adversely affected.

Means for Solving the Problems In order to solve the above problems, the present inventors have made extensive efforts in development, and as a result, the present inventors have developed a method for co-crosslinking the rubber component and the bituminous component into a matrix consisting of a rubber component and a bituminous component. The inventors have discovered that a damping sheet can be formed from a material containing a crosslinkable thermosetting resin, a specific tackifier, and a specific inorganic filler in specific amounts, respectively, and have completed the present invention.

<Implementation mode> Hereinafter, the vibration damping sheet of the present invention will be explained in detail.

In the following explanation, the compounding unit "parts" means "parts by weight" unless otherwise specified.

(1) The matrix (base material) consists of 20 to 80 parts of a rubber component and 80 to 20 parts of a bituminous component. If the rubber component is less than 20 parts, it will become very brittle after heat treatment,
Furthermore, there is no effect of improving vibration damping performance on the high temperature side due to co-crosslinking that occurs during the curing reaction of the thermosetting resin, which will be described later. Furthermore, if the bituminous component is less than 20 parts, thermal fluidization during heat treatment is insufficient, and problems tend to occur in the ability to follow the uneven shape of the vehicle floor surface.

The above rubber components include NR, NBR, IIR, and EPD.
Various rubbers such as M, EPM, SBR, CR, etc. or a mixture of one or more recycled rubbers thereof are used.

As the bituminous component, one or a mixture of two or more of straight asphalt, blown asphalt, and other natural asphalts is used.

(2) Add to the matrix the following: (10 to 100 parts of a crosslinkable thermosetting resin co-crosslinkable with the rubber component), (10 to 150 parts of a tackifier, and (5) 50 to 500 parts of an inorganic filler). Blend parts.

Here, if the thermosetting resin is less than 10 parts, no improvement in damping performance will be observed over the entire range from low to high temperatures, and if it exceeds 100 parts, the thermosetting resin will become a matrix phase and exhibit damping performance. Since the glass transition temperature of the material shifts to a higher temperature than the normal operating environment temperature (0 to 80° C.) such as on the floor of a vehicle, it is difficult to obtain the desired vibration damping performance.

If the amount of the tackifier is less than 10 parts, the effect of improving damping properties will be small (presumably because the inorganic filler does not have a bonding effect with the base material), and if it exceeds tSO part, the damping performance at high temperatures will be reduced. decreases (due to increased fluidity at high temperatures).

If the inorganic filler is less than 50 parts, the blending effect of the inorganic filler, that is, the improvement effect on vibration damping performance will not be achieved, and the
The improvement effect of vibration damping performance hardly increases even if it exceeds
Furthermore, crosstalk and the like deteriorate, resulting in a decrease in work efficiency.

■Unsaturated polyester resin, silicone resin.

Examples include phenol resin, diallyl phthalate resin, melamine resin, and epoxy resin.

Here, the rubber components are NR, SBR, and EPDM.

In the case of EPM, BR, fluororubber, silicone rubber, urethane rubber, etc., select an unsaturated polyester resin, silicone resin, diallyl phthalate resin, epoxy-acrylate resin, etc. to be used in combination with an organic peroxide as a curing agent.

Further, in the case of IIR, NBR, CR, etc., the rubber component is selected from phenol resin mixed with hexamethylenetetramine.

■One or two selected from petroleum hydrocarbon resin, coumaron resin, phenol resin, xylene resin, and rosin
Examples include mixtures of more than one species.

Usually, these tackifiers have a softening point of 60°C or higher.
The petroleum-based hydrocarbon resin may be either aromatic or aliphatic 9 synthetic polyterpene, but especially if you want to shift the damping performance to the high temperature side, aromatic with a high softening point is desirable, such as the coumaron-based resin mentioned above. A typical resin is coumaron-indene resin. Examples of the phenolic resin include pt-butylphenol e-acetylene resin, novolac resin (B stage), and terpene/phenol resin.

(2) One or a mixture of two or more selected from a silicon compound group mainly consisting of 5iQ2, calcium carbonate (heavy/light), or barium sulfate (palite powder/sedimentable). These inorganic fillers may be either powder (powder, flake, granule, etc.) or am,
The size of the former is 0.5 to 500 gm, and the length of the latter is 25 mm. The group of silicon compounds mainly composed of 5i02 mentioned above includes powdered clay (hard and soft), talc, milled glass, glass flakes, fibrous glass fiber, etc. Inorganic foams such as shirasu balloons, glass balloons, and foam stones with specific gravity <0.6 can also be used. When this inorganic foam is used, it is possible to reduce the weight of the damping sheet.

A sheet (usually 2 to 6
III11) to form a vibration damping sheet. This damping sheet is attached to the vehicle floor by punching it into a predetermined shape, installing it on the vehicle floor, and then passing it through a drying oven for heat treatment. During that time, the vibration damping sheet is thermally softened or fluidized and After fully adapting to the surface shape, it is firmly fused. At this time, due to the heat of the heat treatment process, the blended thermosetting resin is crosslinked and cured by itself, and co-crosslinked with the rubber component, thereby reliably contributing to an increase in vibration damping performance.

<Example> After kneading the materials with the compositions shown in Table 1 with a Nigoo,
Each vibration damping sheet was obtained by extruding it into a sheet-like material of 11 mm.

For each of the above vibration damping sheets, tests were conducted on the following items. The results of each test are shown in Table 2.

(a) Vibration damping test Each vibration damping sheet was punched out and a steel plate base (200X200X
0.8 mmt), heat treatment was performed at 150° C. for 30 minutes, and each test piece was obtained by adhering it to an iron plate substrate.

For each test piece, a vibration analysis device (mechanical impedance method) manufactured by Akashi Seisakusho was used at 0°C, 25°C,
40℃, 60℃, 80℃, 100'0, 120'C
! The loss coefficient (η) at each temperature was measured. In addition,
The measurement frequency range is 20-1000Hz.

(b) Shear adhesion test A test piece cut out from each vibration damping sheet to a width of 25 mm and a length of 120 mm was cut out from a 120 x 25 x 1 m!1 steel plate.
1!111 lap, heat fused under the conditions of 150℃ x 30 minutes, and then tested the shear adhesive strength (2
5°C, 80°C).

(C) Low temperature impact test Each damping sheet has a width of 100+*m and a length of 150t+w.
The test piece cut out is 250 x 150 x 1
After heating and fusing to a steel plate of mm5t at 150°C for 30 minutes.

A 50g steel ball is dropped in a low temperature atmosphere of -20℃,
The height at which cracks occur in the test piece was determined.

(d) Shape following test on uneven sheet metal A test piece cut out from each damping sheet to a width of 200 mm and a length of 200 m5+ was placed on the uneven sheet metal shown in Figure 52 and heated at 150°C for 30 minutes. Looking at the shape followability after treatment, as shown in FIG. 1, those in close contact with no gaps were rated as "O'°," and those with gaps were rated as "°×°°."

<Effects of the Invention> Into the matrix shown in Figure 1, specific amounts of ■crosslinked thermosetting resin capable of co-crosslinking with the rubber component, ■specific tackifier, and ■specific inorganic filler are blended. As is clear from the above embodiments, the following effects can be achieved by forming the material using the above-mentioned material.

(a) Even with a small amount of inorganic filler, a large improvement in vibration damping properties can be obtained, and workability such as kneading and moldability is excellent.

(b) It has excellent fluidity during heat treatment and adapts well to the uneven shape of the vehicle floor surface.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a damping sheet of the present invention adhered to a steel plate having an uneven shape, and FIG. 2 is a dimensional cross-sectional view of the steel plate in FIG. 1. 1... Steel plate. 2... Vibration control sheet.

Claims (1)

[Scope of Claims] For 100 parts by weight of a matrix consisting of 20 to 80 parts by weight of a rubber component and 80 to 20 parts by weight of a bituminous component, (a) a thermosetting crosslinking system capable of co-crosslinking with the rubber component; Resin: 10 to 100 parts by weight (b) One or more tackifiers selected from petroleum hydrocarbon resins, coumaron resins, phenol resins, xylene resins, and rosins: 10 to 150 parts by weight Part (c) Made of a material containing 50 to 500 parts by weight of one or more inorganic fillers selected from a silicon compound group mainly composed of SiO_2 and calcium carbonate or barium sulfate. A vibration damping sheet characterized by: