JPH0223342B2 - - Google Patents

Description

[Detailed description of the invention]

<Technical Field> The present invention is a vibration damping sheet that is attached to a vibrating metal base such as a vehicle floor surface to attenuate the source of vibration, and the upper surface of the adhesive layer is coated with petroleum-based hydrocarbon resin, It relates to a constraining layer formed of a compound containing an inorganic filler and a plasticizer. <Background Art> 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. Therefore, it is required to exhibit good fluidity when heated and melted, and furthermore, vibration damping sheets are often subjected to impact from flying stones etc. through the vehicle floor while driving on rough roads, so impact resistance is also required. . If the restraint 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, filing date:
On September 15, 1980 (see Japanese Patent Application Laid-Open No. 60-65929), petroleum resin,
Formulations containing inorganic fillers and plasticizers have been proposed. 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 the above, the present invention provides a vibration damping sheet in which a constraining layer is formed of a compound containing a petroleum resin, an inorganic filler, and a plasticizer, which hardly causes a decrease in damping force. The purpose is to improve the fluidity of the constrained layer. The vibration damping sheet of the present invention achieves this purpose by adding 0.5 to 0.5 to 100 parts by weight of acid-modified diene polymers (including esterified products) to 100 parts by weight of petroleum resin in the constraining layer formulation.
This is achieved by containing 8 parts by weight. <Description of each component> In the following description, the number of blended parts "parts" is a weight unit unless otherwise specified. As shown in FIG. 1, the damping sheet consists of an adhesive layer 1 and a restraining layer 2 formed on the upper surface thereof. The 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 blending them with asphalt using a kneader or the like and extruding the mixture. As the rubber material here, various rubbers such as NBR, IIR, EPDM, and SBR, or recycled rubber thereof can be used. The thickness of this adhesive layer 1 is usually 0.05 to 5 mm (preferably 0.2
~2mm). Restriction layer 2 is made of the following petroleum resin (A) and inorganic filler.
(B), plasticizers (C), and acid-modified diene polymers (D) were melt-mixed into adhesive layer 1.
It is formed to a predetermined thickness on the upper surface by a coating method such as flow coating, brush coating, or roll coating. The thicker the restraining layer 2, the greater the damping force, but from the perspective 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 restraining effect, and is usually 0.05 to 10 mm (preferably 0.2 to 3 mm). do. (A) Petroleum resin...Any commercially available one with a softening point of 60 to 130°C may be used, such as synthetic polyterpene, aliphatic, aromatic, cycloaliphatic, unsaturated hydrocarbon, and hydrogenated products thereof. can be exemplified. 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 silicon compounds mainly composed of SiO ₂ and calcium carbonate (heavy/light) or barium sulfate (barite powder/sedimentable). The form of the inorganic filler may be either powder (powder, flake, granule, etc.) or fiber, the former having a size of 0.5 to 500 μm, and the latter having a length of <25 mm. The group of silicon compounds mainly composed of SiO ₂ mentioned above includes powdered clay (hard clay).
soft), talc, milled glass, glass flakes, fibrous glass fibers, etc.
Furthermore, as special materials, inorganic foams such as white glass balloons, glass balloons, and foam stones with a bulk specific gravity of <0.6 can also be used. When this inorganic foam is used, the weight of the constraint layer can be reduced. This inorganic filler increases the stiffness of the constraining layer and increases the damping force, and for unknown reasons - inorganic fillers generally tend to reduce the impact resistance of polymers - improves the impact resistance of petroleum resins. Improve. The amount of inorganic filler blended is usually set to 100 parts of petroleum resin from the viewpoint of achieving these effects and mixing workability.
100 to 800 parts (preferably 200 to 500 parts). (C) Plasticizers...In addition to various ester plasticizers and process oils, linseed oil, cottonseed oil, soybean oil,
Includes natural oils and fats such as castor oil, polymer oils such as polybutene oil, polybutadiene oil, and polypentadiene oil, liquid resins such as liquid hydrocarbon resins, liquid terpene resins, liquid rosins, alkyd resins, xylene resins, etc. Examples of ester plasticizers include dibutyl phthalate, di(2-ethylhexyl) phthalate (DOP), di-n-butyl adipate, dimethyl isophthalate, and di-butyl phthalate, which generally have good compatibility with petroleum resins.
Preferred are n-butyl sebacate, di-n-butyl nurate, di-n-butyl fumarate, di-n-butyl stearate, etc. As the process oil, paraffinic or naphthenic oils having good compatibility with the above petroleum resins are used. desirable. 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 blending amount of plasticizers is usually 3 to 3 parts per 100 parts of petroleum resin from the viewpoint of achieving these effects and maintaining damping force.
25 parts (preferably 8 to 20 parts). (D) Acid-modified diene polymers: refers to acid-modified diene polymers obtained by modifying liquid conjugated diene polymers with ethylenically unsaturated carboxylic acids (including anhydrides), and esterified products thereof. Here, the conjugated diene polymer refers to monopolymerization or copolymerization of conjugated dienes such as 1,3-butadiene, 1,3-pentadiene, and isoprene, or olefins such as ethylene and propylene, and/or styrene, α - Copolymerized vinyl monomers such as methylstyrene, molecular weight n=
200 to 15,000 (preferably 300 to 1,000) 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,
Examples include tetrahydrophthalic anhydride and endomethylenetetrahydrophthalic 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 when added in small amounts, and the amount added is 0.5 to 8 parts (preferably 2 to 6 parts) per 100 parts of petroleum resin. . If the amount is less than 0.5 parts, the fluidity cannot be improved, and if it exceeds 8 parts, the impact resistance will be adversely affected, and the viscosity upon heating and melting will be too low, making it easy for the inorganic filler to settle, which is not desirable. As shown in Fig. 2, the vibration damping sheet having the above structure is set on the vehicle floor surface 3 and then heat-treated through a drying oven, whereupon it becomes thermally softened or fluidized and fully conforms to the vehicle floor surface, and is then cooled. Then, the restraining layer 2 becomes substantially rigid and is adhered to the vehicle floor surface 3 as shown in FIG. <Example> The adhesive layer was made by kneading the above-mentioned composition in a kneader and then extruding it into a sheet with a thickness of 1 mm.
It was cut and formed into a 200mm opening. Blending composition: 100 parts recycled butyl rubber Tackifier (aromatic hydrocarbon resin; softening point
(100℃) 80 parts Heavy calcium carbonate 300 parts Polybutene 50 parts DOP 50 parts For the constraining layer, a formulation for the constraining layer with the following composition using each acid-modified diene polymer shown in Table 1 was heated at 200℃.
The mixture was melt-mixed for 30 minutes and poured onto the top of the adhesive layer to form a 2 mm thick layer. 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 10 parts Acid-modified diene polymers 5 parts After setting each of the above damping sheets on a steel plate base (0.8 mmt) , heat treated at 140℃ x 60 minutes,
This was used as a test piece for vibration damping force and impact resistance tests for each of the Examples and Comparative Examples. The damping effect was determined by the loss coefficient η calculated from the measurement results using the damping method in a room temperature atmosphere. Impact resistance is measured by dropping a steel ball (usually 50 g) onto the iron plate with the above test piece supported on a bridge with the iron plate side up, and measuring the weight x height (g cm) at which cracks occur in the restraining layer. )”. In addition, the fluidity of the constrained layer was determined by heating and melting 30 g of the compound of each example (comparative example) at 200°C and dropping it onto an aluminum plate from a height of 4.5 cm, and checking the spread of the compound after falling. It 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 mixing and coating workability of the composition for the constraining layer as well as 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, in all of the Examples, compared to the Comparative Example (addition of acid-modified diene polymer powder), there was almost no decrease in damping force (loss coefficient), and impact resistance and fluidity, especially fluidity, were improved. It's improving. These reasons are due to the fact that by adding acid-modified diene polymers having a polar part and a non-polar part to the constraining layer formulation, compatibility between the polar inorganic filler and the non-polar petroleum resin can be improved. It is presumed that this is because the condition improves.

【table】

【table】 [Brief explanation of drawings]

FIG. 1 is a partial sectional view of the vibration damping sheet of this invention.
FIG. 2 is a sectional view showing a state in which the vibration damping sheet of the present invention is adhered to the floor surface of a vehicle. 1...Adhesive layer, 2...Restriction layer, 3...Vehicle floor surface (metal base).

Claims (1)

[Scope of Claims] 1. 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 following acid-modified diene polymer is included in the compound. Coalescings (including esterified products) (A)
A damping sheet containing 0.5 to 8 parts by weight of the above petroleum resin based on 100 parts by weight. (A) Acid-modified diene polymers made by modifying liquid conjugated diene polymers with ethylenically unsaturated carboxylic acids (including anhydrides).