JPH05269925A - Laminate composite plywood for vehicle flooring material - Google Patents

Abstract

PURPOSE:To lessen the variation of characteristics generated by the variation of temperature, increase the loss factor of a laminate composite plywood and improve the vibration suppressing performance of the plywood to a large extent as a result. CONSTITUTION:A laminate composite plywood for a vehicle flooring material of a damping material 2 is bonded with plywoods 1, 1 respectively on the surface and rear face, and said damping material 2 is composed by forming a kneaded material composed of at least an ethylene vinyl acetate copolymer(EVA) and the like added to isobutylene-isoprene rubber(IIR).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle, particularly an automobile flooring. More specifically, the present invention relates to a laminated composite plywood suitable for use as a floor material such as a bath, which requires reduction of noise in the room.

[0002]

2. Description of the Related Art In recent years, vehicles, such as sightseeing buses and high-speed buses, are in the direction of upsizing, and there is an increasing demand for improving indoor comfort. In order to satisfy such a demand, it is necessary to improve the vibration, noise and riding comfort in the room due to the structure of the vehicle body. The vibration propagation noise and the air propagation sound accompanying the vibration of the floor plate largely contribute to the vibration and noise in the bath room. Conventionally, as this type of floor material, a laminated composite plywood in which wood plywood is bonded to the front surface and the back surface of an asphalt pitch-based damping material has been used.

[0003]

However, although the conventional laminated composite plywood has superior vibration damping performance to that of only wood plywood, it is not always sufficient because the loss coefficient of the laminated composite plywood changes greatly with temperature. There was a problem that it was not possible to obtain various vibration damping effects. SUMMARY OF THE INVENTION An object of the present invention is to provide a laminated composite plywood for vehicle flooring that has a small change in characteristics due to temperature changes and can sufficiently increase the loss factor of the plywood and is easy to handle.

[0004]

A structure of the present invention for achieving the above object will be described with reference to FIG. 1 corresponding to an embodiment. The present invention relates to a laminated composite plywood for vehicle flooring in which the wood plywood 1, 1 is bonded to the front and back surfaces of the damping material 2 with adhesives 3, 3, respectively. A vinyl acetate copolymer (hereinafter referred to as EVA) is added and kneaded, and a kneaded product is formed into a sheet.

The present invention will be described in detail below. II in the kneaded mixture
The compounding ratio of R and EVA is IIR: EVA = 70 to 30: 3.
It is preferably 0 to 70. When the IIR exceeds 70%, the loss coefficient of the composite plywood at high temperature decreases, and conversely, when it is less than 30%, the loss coefficient of the composite plywood at low temperature of 10 ° C. or less tends to decrease. The kneaded product is II
When the total amount of R and EVA is 100 parts by weight, a general plasticizer may be contained in an amount of about 30 to 40 parts by weight, and it is preferable to add a filler. Examples of the filler include graphite, talc, calcium carbonate, clay, carbon, silica and the like. Among them, scale-like fillers such as graphite and talc are preferable in terms of improving the loss factor of the composite plywood. When the total amount of IIR and EVA is 100 parts by weight, it is preferable to add 30 to 100 parts by weight of the scale-like filler. When it is less than 30 parts by weight, the effect of improving the loss factor of the composite plywood is poor, and when it exceeds 100 parts by weight, the sheet workability of the damping material deteriorates depending on its average particle diameter.

Although the scale-like filler may be added alone, a non-scale-like filler commonly used in polymers such as carbon and calcium carbonate may be used as a damping material, reinforcement of composite plywood, or cost reduction. For the purpose of, etc., it may be added together with the scale-like filler. Further, a plasticizer used for IIR, such as a paraffin plasticizer or DBP, for the purpose of supplementing the sheet workability when a filler is added to the damping material or for averaging the temperature dependence of the loss coefficient of the composite plywood. , DHP, DOP, and other phthalic acid ester plasticizers, or DOA, and other adipic acid ester plasticizers may be added in the amounts described above. Further, it is preferable to bond the wood plywood 1,1 to the damping material 2 with the adhesives 3,3. As this adhesive, for example, a phenolic adhesive,
Examples include chloroprene rubber adhesives and epoxy adhesives. Of these, epoxy adhesives are preferable because of their durability and strength.

[0007]

Since the damping material is sandwiched and bonded between the pair of wood plywood, the damping effect of the damping material as a whole enhances the vibration damping effect of the laminated composite plywood. On the other hand, II contained in the damping material
Due to the polymer structure, R has few double bonds and thus has excellent resistance to aging. Further, R has low impact resilience and therefore has excellent vibration absorption. EVA has the effect of improving the loss coefficient on the high temperature side (30 to 50 ° C) at the temperature at which the composite plywood of the present invention is used, and reduces the temperature dependence of the damping material. Further, by adding a filler such as fine talc, it is possible to enhance the mechanical properties of the laminated composite plywood and enhance the loss coefficient. As a result, if the laminated composite plywood of the present invention is laid in a room as a floor material for a vehicle, noise in the room is effectively reduced.

[0008]

Embodiments of the present invention will now be described in detail with reference to the drawings. As shown in FIG. 1, the laminated composite plywood for flooring of this embodiment has a damping material 2 having a thickness of about 1 mm and a wood plywood 1, 1 having a thickness of about 5 to 10 mm, and an epoxy adhesive 3,3. It is configured by bonding.

The characteristic construction of this embodiment is that the damping material 2 is formed into a sheet by kneading the kneaded material by adding IIR as a high molecular weight plasticizer such as EVA, a filler such as fine talc, and a general plasticizer. There is a point that will be done. IIR is a copolymer of isobutylene and isoprene, and EVA is a copolymer of ethylene and vinyl acetate. The damping material 2
Can be obtained by uniformly kneading IIR, EVA, a filler, and further a plasticizer and the like with a kneader, a blender or the like, and then forming the kneaded product into a sheet with a calendar roll machine, an extruder or the like. Sheet forming in an extruder is performed after attaching a roller die to the head of the extruder.

In order to investigate the performance of the laminated composite plywood for flooring of this example, test pieces were prepared from the following test materials and tested. (1) Shape of test body A damping material was sandwiched between a plywood serving as a lower surface and a plywood serving as an upper surface, and a plate-shaped test body cut into a rectangle of 200 × 300 mm was used. The bonding of each member was performed by applying an epoxy resin at about 200 g / m ² . (2) Test material Damping material: The damping material of the example was kneaded by kneading the compositions blended in the compounding ratios shown in Table 1, further kneaded by rolls, and the obtained roll sheet was pressed to give a predetermined composition. It was thick. The damping material of the comparative example is
A commercial asphalt pitch damping material,
It was adjusted to a predetermined thickness with a press. The numerical values in Table 1 are parts by weight. Plywood: Apiton plywood (material code M) was used. (Hereafter, margins on this page)

[0011]

[Table 1]

(3) Test method The loss coefficient was measured from the half width of the mechanical impedance at the resonance frequency, and the loss coefficient at 200 Hz was determined by interpolation. The measurement frequency range is 1 to 1000.
Hz and the measurements were performed at temperatures of 5 ° C, 25 ° C and 45 ° C, respectively. (4) Test Results Table 2 shows the test results of the examples and the comparative examples. In Table 2, the numerical values of plywood and damping material are the thickness (unit: m
m). As is clear from Table 2, the test pieces of the laminated composite plywood according to the examples obtained a high loss coefficient, whereas the test pieces according to the comparative examples all had an extremely bad loss coefficient.

[0013]

[Table 2]

(3) Test method The loss coefficient was measured from the half width of the mechanical impedance at the resonance frequency, and the loss coefficient at 200 Hz was determined by interpolation. The measurement frequency range is 1 to 1000.
Hz and the measurements were carried out at temperatures of 5 ° C, 25 ° C and 45 ° C, respectively. (4) Test Results Table 2 shows the test results of the examples and the comparative examples. In Table 2, the numerical values of plywood and damping material are the thickness (unit: m
m). As is clear from Table 2, the test pieces of the laminated composite plywood according to the examples obtained a high loss coefficient, whereas the test pieces according to the comparative examples all had an extremely bad loss coefficient.

Test samples of the laminated composite plywood of Examples 1 to 7 were used.
It was exposed to the atmosphere at 0 ° C. for 1000 hours. Moreover, Example 1
The test body of No. 3 was immersed in warm water of 40 ° C. for 1000 hours.
In each case, the damping property of the test body was not deteriorated, and no external defect such as peeling or warpage was observed. When the laminated composite plywood of Examples 1 to 3 was actually laid as a floor material in a bus vehicle, the vehicle interior noise was 4 to 6 dB as compared with the plywood of Comparative Example 5 using a conventional asphalt pitch-based damping material. Reduced.

[0016]

As described above, according to the present invention, since IIR and EVA are used as the matrix polymer of the damping material sandwiched between the pair of wood plywood,
The characteristics of the damping material change little with changes in temperature, and the loss coefficient of the laminated composite plywood can be increased, and as a result, the vibration damping performance of the plywood can be greatly improved. Since the laminated composite plywood of the present invention can be processed by the same method as in the case of a single wood plywood product, there is no fear that the handling of the flooring material will deteriorate.

[Brief description of drawings]

FIG. 1 is a sectional view of a laminated composite plywood for vehicle flooring material according to an embodiment of the present invention.

[Explanation of symbols]

 1 Wood plywood 2 Damping material 3 Adhesive

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location B62D 29/04 A // C08L 23/08 LDJ 7107-4J

Claims (2)

[Claims] 1. A laminated composite plywood for vehicle flooring, wherein a wood plywood (1,1) is bonded to the front and back surfaces of a damping material (2), wherein the damping material (2) is butyl rubber and at least ethylene vinyl acetate A laminated composite plywood for vehicle flooring, characterized by being formed into a sheet from a kneaded product obtained by adding and kneading. 2. The compounding ratio of butyl rubber and ethylene vinyl acetate copolymer in the kneaded product is butyl rubber: ethylene vinyl acetate copolymer = 70 to 30:30 to 70.
Laminated composite plywood for vehicle flooring as described.