JPS60110443A - Vibration-damping sheet - 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] Technical Field> The present invention relates to a vibration damping sheet that is attached to a vibrating metal substrate such as a vehicle floor surface to attenuate vibrations. It relates to a constrained layer formed of a compound containing a petroleum-based hydrocarbon resin, an inorganic filler, and a plasticizer.

BACKGROUND TECHNOLOGY In order to obtain a large vibration damping force, the material for the restraining layer in a vibration damping sheet is desired to have not only high rigidity but also good adhesion to the adhesive layer, and also from the viewpoint of workability. There is a demand for good fluidity when melted by heating.
Furthermore, the damping sheet is often subjected to impact from flying stones etc. through the vehicle floor surface while driving on rough roads, and is therefore required to have impact resistance. If the restraining layer cracks due to poor impact resistance, the damping force will be significantly reduced.

In order to meet the above requirements, a patent application filed by the same person as the applicant (Japanese Patent Application No. 58-170109, application date: 1973)
(September 15, 1999), a formulation containing a petroleum resin, an inorganic filler, and a plasticizer is proposed as a material for a constraining layer. When a restraining layer is formed with this compound, a large vibration damping force can be obtained and the impact resistance is also excellent, but even though it contains plasticizers, the fluidity of the compound is insufficient, making it difficult to work during molding etc. was not necessarily good. If a large amount of plasticizer is added to obtain sufficient fluidity, the above problem can be solved, but on the other hand, the rigidity of the constraining layer, that is, the vibration damping force is greatly reduced, which is not desirable.

<Disclosure of the Invention> In view of item 2, the present invention provides a vibration damping sheet in which a restraining layer is formed of a compound containing a petroleum resin, an inorganic filler, and a plasticizer, with the result that the reduction in damping force is almost suppressed. The purpose is to improve the fluidity of the constrained layer without inviting it.

The damping sheet of the present invention achieves this objective by containing 0.5 to 8 parts by weight of acid-modified diene polymers (including esterified products) per 100 parts by weight of petroleum resin in the constraining layer formulation. This is achieved by

<Description of each component> In the following explanation, the number of parts mixed is 1 part by weight unless otherwise specified.

As shown in FIG. 1, the vibration damping sheet consists of an adhesive layer 1 and a restraining layer 2 formed on the upper surface of the adhesive layer 1. The stranded adhesive layer 1 is formed in the same manner as a conventional adhesive sheet. That is, it is made by kneading various rubber compounds or mixtures thereof with asphalt using a kneader or the like and extruding the mixture. As the rubber material, various rubbers such as NBRlI IR, EPDM, and SBR, or recycled rubber thereof can be used. The thickness of this adhesive layer 1 is usually set to 0.05 to 5 Il111 (preferably 0.2 to 2 m+a) from the viewpoint of weight reduction, although the thicker the thickness, the greater the vibration damping effect.

The constraining layer 2 is made of the following petroleum resin (A), inorganic filler (B)
), plasticizers (C), and acid-modified diene polymers (D) are melt-mixed onto the top surface of the adhesive layer l by a coating method such as flow coating, brush coating, or roll coating. Form to a predetermined thickness. The thicker the restraint layer 2, the greater the damping force, but from the standpoint of reducing the weight of the vehicle, it is desirable that the thickness be as thin as possible within the range that still exerts the restraint effect. ~3 servings).

(A) Petroleum resin...A resin coated with a softening point of 60 to 130°C may be used, including synthetic polyterpene-based, aliphatic-based, aromatic-based, cycloaliphatic-based, unsaturated hydrocarbon-based and their water. Examples include additives. From the viewpoint of impact resistance (flexibility) of the constraining layer, it is desirable to use a material other than aromatic. These petroleum resins serve as the base material of the constraining layer, and since they themselves have strong adhesive properties, they adhere well to the adhesive layer, reliably exert a constraining effect, and contribute to improving vibration damping properties.

(B) Inorganic filler: one or a mixture of two or more selected from a silicon compound group mainly composed of 5i02 and calcium carbonate (heavy/soft) or barium sulfate (palite powder/sedimentable).

The form of inorganic filler is granular (powder, flake,
The size of the former should be 0.5 to 500 mm, and the length of the latter should be 25 mm. Examples of the silicon compound group mainly composed of 5i02 include powdered clay (hard and soft), talc, milled glass, glass flakes, and fibrous glass fiber. Specific gravity <0
．． Inorganic foams such as glass balloons, glass balloons, and foamed stones can also be used. When this inorganic foam is used, the weight of the constraint layer can be reduced. This inorganic filler increases the rigidity of the constraint layer and increases the damping force, and
Although the reason is unknown, □Generally, inorganic fillers tend to reduce the impact resistance of polymers.-1 Improve the impact resistance of petroleum resins. From the viewpoint of achieving these effects and mixing workability, the amount of inorganic filler blended is usually 100 to 800 parts (preferably 200 to 50 parts) per 100 parts of petroleum resin.
0 copies).

(C) Plasticizers: In addition to various ester plasticizers and process oils, natural oils such as linseed oil, cottonseed oil, soybean oil, and castor oil, and polymer oils such as polybutene oil, polybutadiene oil, and polypentadiene oil. , liquid hydrocarbon resins, liquid terpene resins, liquid resins such as liquid rosin, alkyd resins, xylene resins, etc.

Ester plasticizers include dibutyl phthalate and di(2-ethylhexyl), which generally have good compatibility with petroleum resins.
Phthalate (DOP), di-n-6-butyl adipate, dimethyl isophthalate, di-n-
Butyl sebacate, di-n-butyl nurate, di-n-
Butyl fumarate, di-n-butyl stearate, etc. are preferred, and the process oil is preferably a paraffinic or naphthenic oil that has good compatibility with the petroleum resin.

These plasticizers suppress the increase in melt viscosity caused by blending the inorganic filler, and also improve the impact resistance of the constraining layer. The amount of plasticizers to be blended is usually 3 to 25 parts (preferably 8 to 20 parts) per 100 parts of petroleum resin in order to achieve these effects and maintain damping force.

(D) Acid-modified diene polymers: acid-modified diene polymers obtained by modifying a liquid conjugated diene polymer with an ethylenically unsaturated carboxylic acid (including anhydride), and esterified products thereof.

Here, the conjugated diene polymer is 1,3-butadiene,
Refers to monopolymerization or copolymerization of conjugated dienes such as 1,3-pentadiene and isoprene, or copolymerization of them with olefins such as ethylene, propylene, and/or vinyl monomers such as styrene and α-methylstyrene. , molecular weight 11an=200-15000 (preferably 300
~1000) is used in liquid form. Examples of α,β-unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, and endomethylene. Examples include tetrahydrophthalic anhydride. The amount of ethylenically unsaturated carboxylic acid used is such that the saponification value of the acid-modified diene polymer as a reaction product is in the range of 5 to 160 (preferably 20 to 140).

These acid-modified diene polymers have the effect of improving the fluidity of the constrained layer with a small amount of blending, and the blending amount is 1/1 of the petroleum resin.
0.00 parts to 0.5 to 8 parts (preferably 2 to 6 parts). If it is less than 0.5 parts, the above-mentioned fluidity improvement cannot be achieved, and if it exceeds 8 parts, it will adversely affect the impact resistance and the viscosity upon heating and melting will decrease too much, which is undesirable because the inorganic filler tends to settle.

As shown in Fig. 2, the vibration damping sheet having the above structure is set on the vehicle floor 3 and then heat-treated through a drying oven, where it becomes thermally softened or fluidized and fully adapts to the vehicle floor. When cooled, the constraint layer 2 becomes substantially rigid and is adhered to the vehicle floor surface 3 as shown in FIG.

<Example> The adhesive layer was prepared by mixing the following composition in a kneader, extruding it as a sheet with a thickness of lam, and pressing it with 20011I.
It was cut into one piece.

Blending composition: Recycled butyl rubber 100 parts Tackifier (aromatic hydrocarbon resin; softening point 100°C) 80 parts Heavy calcium carbonate 300 parts Polybutene 50 parts DOP 50 parts The constraining layer was made of each acid-modified diene shown in Table 1. A restraining layer formulation using polymers having the following composition was melt-mixed at 200°C for 30 minutes, and then flow-coated onto the top surface of the adhesive layer to form a 2-inch thick one. In addition, in the comparative example, the acid-modified diene polymer was set to 0 and the DOP was set to 15 parts in the blending composition of the example.

Blend composition: Aliphatic hydrocarbon resin 100 parts (softening point 95°C) Heavy calcium carbonate 350 parts DOP lO part acetic acid-modified diene polymers 5 parts Each of the above vibration damping sheets was attached to an iron plate substrate (0.8■■t) After setting it on top, it was heat-treated under the conditions of 140'OX 60 minutes to prepare test pieces for vibration damping force and impact resistance tests of each example and comparative example.

The damping effect was determined by the loss coefficient η calculated from the measurement results using the damping method in a room temperature atmosphere. The impact resistance was measured by supporting the above test piece with the iron plate side up, using a steel ball (
(usually 50 g) was dropped onto a steel plate, and the time at which cracks occurred in the restraining layer was determined by weight x height g II Cll). In addition, the fluidity of the constrained layer -l 〇 - was determined by heating and melting 30 g of the formulation of each example (comparative example) at 200°C and dropping it onto an aluminum plate from a height of 4.5 mm. The spread of the formulation was measured and expressed as the average value of the major axis and minor axis. The test results are shown in Table 2.

<Effects of the Invention> The vibration damping sheet of the present invention has a restraining layer formed of a compound containing a petroleum resin, an inorganic filler, and a plasticizer. By adding diene polymers, the fluidity of the constrained layer can be improved with almost no reduction in damping force. Therefore, the workability of mixing and coating the compound for the constraining layer and the workability of adhering it to the floor surface are improved.

This is supported by the test results in Table 2 in the above examples. In other words, the damping force (loss coefficient) in each of the Examples was higher than that in the Comparative Example (no acid-modified diene polymer added).
Impact resistance and fluidity, especially fluidity, are improved with almost no decrease in These reasons are due to the compatibility (compatibility) between the polar inorganic filler and the non-polar petroleum resin, which is achieved by aging acid-modified diene polymers having a polar part and a non-polar part in the constraining layer formulation. ) is presumed to be improved.

Table 1 Table 2

[Brief explanation of drawings]

FIG. 1 is a partial cross-sectional view of the vibration damping sheet of the present invention, and FIG. 2 is a cross-sectional view showing the vibration damping sheet of the present invention adhered to the floor of a vehicle. l...adhesive layer, 2...restraint layer, 3...vehicle floor surface (metal base). -13- Figure 1

Claims (1)

[Scope of Claims] A vibration damping sheet in which a restraining layer is formed on the upper surface of an adhesive layer with a compound containing a petroleum resin, an inorganic filler, and a plasticizer, and the compound contains the following acid-modified diene polymer. kind (
A vibration damping sheet containing 0.5 to 8 parts by weight of (A) (including esterified products) based on 100 parts by weight of the petroleum resin. (A) Acid-modified diene polymers obtained by modifying a liquid conjugated diene polymer with an ethylenically unsaturated carboxylic acid (including anhydride).