JPS6065929A - Vibrationproof sheet - Google Patents

Abstract

PURPOSE:To improve a working property for molding a restriction layer as well as raise shock resistance by forming the restriction layer constructed on the upper surface of an adhesive layer by blending a specific inorganic filler and plasticizers with a specific resin-like material in a specific amount. CONSTITUTION:A restriction layer 2 is formed on the upper surface of an adhesive layer 1 for a vibrationproof sheet provided for damping vibration while being stuck on the floor surface of a vehicle. The respriction layer 1 is fored by blending a resin-like material having a softening point over 60 deg.C and yielded by mixing one kind or more selected from a group of thermoplastic resin, natural resin and natural asphalt with 10PHR or more of an inorganic filler yielded by mixing one kind or more selected from a group of silicon compounds and calcium carbonate or barium sulfate or by compounding plasticizers comprising various kinds of ester series plasticizers and/or procel oil in the above inorganic filler by 2.5 to 10wt%.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a vibration damping sheet for attenuating vibrations by attaching it to a metal substrate that generates vibrations such as a vehicle floor surface, the sheet comprising a restraining layer on the top surface of an adhesive layer. Concerning what is being formed.

Conventionally, vibration damping on vehicle floors, etc. has been done by using various rubber compounds alone or by mixing asphalt with them and then extruding them into adhesive sheets, which are then set on the floor surface, heated and softened, and then allowed to follow the floor surface and are fused. . However, in order to obtain a large damping force using only this adhesive sheet, the sheet must be made thicker, which is undesirable as it increases the weight of the vehicle.

Therefore, an application for utility model registration (Utility Model Application No. 58-35862, filing address: March 12, 1982) filed by the same person as the applicant of the present application was filed.
), the softening point is 60'C! In addition to the above, a damping sheet is proposed in which a restraining layer is formed of a resin-like material made of one or more selected from a group of thermoplastic resins made of specific resins, natural resins, and natural asphalt. has been done.

Although this vibration damping sheet can provide a certain amount of damping force without increasing weight, it is not necessarily sufficient, and the impact resistance of the above-mentioned resinous materials forming the restraining layer is not good. If the vehicle receives an impact from the floor due to flying stones or the like while driving on a rough road, cracks may occur in the restraint layer, which may reduce vibration damping performance.

Therefore, the patent application (patent application filed in 1983) is filed by the same person as the applicant.
No. 142327, filed on August 3, 1982), it is proposed to form a constraining layer by blending a specified amount or more of a specific inorganic filler with a resin-like substance. This damping sheet provides a large damping force and has improved impact resistance to some extent. However, impact resistance is not necessarily sufficient, and the melt viscosity of resin-like substances mixed with inorganic fillers increases significantly.
This had a negative impact on the workability of mixing the inorganic filler, the workability of forming the restraining layer, and the workability of attaching the vibration damping sheet to the floor surface.

In view of the above, the present invention provides a vibration damping sheet in which a constraining layer is formed by mixing a specific inorganic filler with a specific resin-like material, and provides a vibration damping sheet that has improved mixing workability of the inorganic filler,
The vibration damping sheet of the present invention has good workability in forming the constraining layer and workability in adhering it to the floor surface, and is intended to improve impact resistance without causing a decrease in damping force. The above-mentioned object of the present invention is achieved by forming a constraining layer using a resin-like material mixed with predetermined amounts of a specific inorganic filler and a specific plasticizer.

Hereinafter, the vibration damping sheet of the present invention will be explained in detail.

In this specification, the compounding amount unit rPHRJ and compounding ratio are weight units.

As shown in FIG. 1, a restraining layer 2 is formed on the upper surface of the adhesive layer l.

The adhesive layer 1 is formed in the same manner as a conventional adhesive sheet. That is, it is made of various rubber compounds or their mixtures with asphalt, which are kneaded with a Ni-Goo or the like and then extruded. Here, the rubber material is NBRlI IR, EPD
Various rubbers such as M and SBR or recycled rubber thereof can be used. The thickness of this adhesive layer 1 is usually 0.05 to 5 mm from the viewpoint of weight reduction, although the thicker it is, the greater the vibration damping effect.
The constraining layer 2 contains the following resinous substance (A), the following inorganic filler (B) at loPHR or higher, and the following plasticizer (C) at (C) / (B) = 1/40 to I/ 10
(weight ratio).

(A) Resin-like substances: thermoplastic resins having a softening point of 60°C or higher and consisting of petroleum-based hydrocarbon resins, coumaron-based resins, phenol-based resins, xylene resins, and rosin derivatives, as well as natural resins and natural One type or a mixture of two or more types selected from asphalt.

The petroleum hydrocarbon resin may be aromatic, aliphatic, or synthetic polyterpene, but aromatic resins with a high softening point are particularly desirable. A typical example of the coumaron-based resin is coumaron-indene resin. Phenolic resins include pt-butylphenol acetylene resin, novolak resin (B stage), terpene resin,
Examples include phenol resin. Examples of rosin derivatives include 5-cured rosin, ester of hydrogenated rosin, and polymerized rosin. Examples of natural resins include rosin, zein, and shellac.

(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 Φ light) or barium sulfate (palite powder 0 sedimentation).

The form of inorganic filler is granular (powder, flake,
It may be in the form of granules, etc.) or fibers, but the size of the former is 0.5 to 500 g, m, and the length of the latter is <25 mm.
shall be. The group of silicon compounds mainly composed of 5i02 mentioned above includes powder-like clay (hard and soft) talc, milled glass, glass flakes, fibrous glass fiber, etc.; <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.

(G) Plasticizers: Refers to various ester plasticizers and/or process oils. As ester plasticizers, dibutyl phthalate and di(2-ethylhexyl) phthalate (D
OP), di-n-butyl adipate, dimethyl isophthalate, di-n-butyl sebacate, di-n-butylnurate, di-n-butyl fumarate, di-n-butyl stearate, etc., and the above-mentioned process oils are preferable. Paraffinic or naphthenic materials having good compatibility with resinous substances are desirable.

Here, each of the above-mentioned resinous substances constituting the matrix phase of the constraining layer has strong adhesive properties, so they increase the interfacial adhesive strength between the constraining layer and the adhesive layer and contribute to increasing the constraining efficiency of the constraining layer. . If the softening point of the resin-like material is less than 60° C., the matrix phase becomes fluidized in a high-temperature atmosphere, making it difficult to perform the function of a constraining layer. Each of the above inorganic fillers increases the rigidity of the restraining layer and contributes to increasing the damping force of the damping sheet.Although the cause is unknown, inorganic fillers generally tend to reduce the impact resistance of the polymer. , improving the impact resistance of resinous materials. Plasticizers have the effect of reducing the solvent viscosity (A) due to the inorganic filler blended with the resinous substance, and also have the effect of improving impact resistance in cooperation with the inorganic filler. The amount of inorganic filler is
Less than oPHR, plasticizer is 1/4 of inorganic filler
If it is less than 0, the above-mentioned combination effect will not be obtained. The upper limit of the blending amount of the inorganic filler is □50 to 800 PHR, which varies depending on the type of the resinous substance and inorganic filler, from the viewpoint of mixing workability with the resinous substance. In addition, the upper limit of the amount of plasticizers to be blended is within a range that does not significantly reduce the stiffness increased by mixing the inorganic filler in the constraint layer, from the perspective of maintaining vibration damping force, and is usually 1/10 of the amount of inorganic filler (weight ratio ) below.

The constraining layer 2 can be easily formed by pouring, brushing, or rolling a mixture of heat-molten resinous substances, inorganic fillers, and the above-mentioned plasticizers onto the upper surface of the constraining layer 1. It is possible to form a product with a predetermined thickness. From the viewpoint of weight reduction, the thickness of this constraining layer 2 is desirably as thin as possible within the range that exerts a constraining effect, and is usually 0.05 to 1.
0 mm, preferably 0.2 to 3 m111.

After the vibration damping sheet with the above structure is set on the vehicle floor 3 as shown in FIG. 2, it is passed through a drying oven and subjected to heat treatment.
The restraining layer 2 is thermally softened or fluidized and sufficiently conforms to the vehicle floor surface, and when subsequently cooled, the restraining layer 2 becomes substantially rigid and is adhered to the vehicle floor surface 3 as shown in FIG.

Next, examples of the present invention will be given, and the vibration damping effect will be confirmed.

<Examples 1 to 5, Comparative Example 1> After kneading a recycled butyl rubber compound with the following composition in a kneader, a sheet-like material with a thickness of 1 mm was extruded to form an adhesive layer. Various parts of inorganic fillers and plasticizers were mixed with each of the resinous substances shown in Table 1, mixed at 210°C for 30 minutes, and then flow-coated to form a 2tw thick restraining layer. Got a sheet.

Blend composition; Recycled butyl rubber 100 parts 9- Tackifier (aromatic hydrocarbon resin; Softening point 100°C) 80 parts Calcium carbonate (heavy) 300 parts Polybutene 50 parts DOP 50 copies Test method> Each of the above vibration damping sheets was attached to a steel plate base (200 mm opening x o.

8 mmt), heat treatment was performed under conditions of 140'0 x 60 minutes, and the damping sheet was adhered to the iron plate substrate to obtain test pieces for each example and comparative example. In addition, in the comparative example, a 3 mmt adhesive sheet made of the following asphalt compound was used.

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 an iron plate, and the weight at which cracks occurred in the restraining layer x height (g cm) was determined. The results are shown in Table 1, and it can be seen that the vibration damping sheet of the present invention has a large vibration damping force and has significantly improved impact resistance.

= 10- The vibration damping sheet of the present invention improves the mixing workability of the inorganic filler and the molding work of the restraining layer by blending a predetermined number of specific inorganic fillers and specific plasticizers into the resinous material forming the constraining layer. In addition, the workability of adhesion to the floor surface is improved, and the impact resistance is significantly improved without causing a decrease in vibration damping force.

−11=

[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. ■...Adhesive layer, 2...Restraint layer, 3...Vehicle floor surface (metal base). Patent application Toyoda Gosei Co., Ltd. 13- 11!1

Claims (1)

[Scope of Claims] In a vibration damping sheet in which a restraining layer is formed on the upper surface of an adhesive layer, the following inorganic filler (B) is added to the resin material (A) at a rate of 10 PHR or more, and a plasticizer (C ) to (C)
/(B) = 1/40 to 1/10 (weight ratio), respectively, and the restraining layer is formed of a damping sheet. (A) 1 having a softening point of 60°C or higher and selected from the group of thermoplastic resins consisting of petroleum-based hydrocarbon resins, coumaron-based resins, phenol-based resins, xylene resins, and rosin derivatives, natural resins, and natural asphalt. A resinous substance formed by a species or a mixture of two or more species. (B) One or two selected from a silicon compound group mainly composed of 5i02 and calcium carbonate or barium sulfate.
An inorganic filler made by mixing more than one species.