JPH03158229A - Lightweight composite material - Google Patents

Abstract

PURPOSE:To make it possible to obtain lightweight composite material, which is excellent in physical strength and formability and easy in manufacturing, by a method wherein inorganic fibers are bound together at least partially by thermoplastic resin as binder so as to form a large number of gaps over the whole mat-like formed body. CONSTITUTION:Glass fibers 2 and polyethylene fibers 3 are charged to a carding machine so as to be mixed and then turned into mat-like material in order to obtain mat-like non-woven fabric after being needle-punched. High density polyethylene film is laminated on one side of said mat-like non-woven fabric, on the other side of which high density polyethylene film and colored olefin- based thermoplastic elastomer sheet are laminated under the condition that the thermoplastic elastomer sheet 4 faces outside. The resultant laminate is pinched between teflon belts and hot-pressed after the thermoplastic resin within it is melted by striking the laminated with hot air. Finally, by sucking the upper and lower teflon belts under vacuum, the thickness of the sheet is restored so as to develop gaps 5 in order to obtain formed body consisting of lightweight composite material.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a light 11 composite material suitable for various interior materials such as ceiling materials for automobiles. Furthermore, the present invention has excellent physical strength and moldability, and is easy to manufacture. Regarding composite materials.

(Prior Art) Composite materials used for automobile ceiling materials, for example, are required to be lightweight and have excellent properties such as rigidity, heat resistance, sound absorption, and thermoformability. As such a material, a porous composite material obtained by impregnating a cloak-like nonwoven fabric made of inorganic fibers with a thermoplastic resin is laminated with a sheet made of a foam such as styrene foam or urethane foam as necessary. Furthermore, a material is used in which a skin material such as a soft vinyl chloride sheet is adhered to the upper layer. Although such materials have excellent characteristics such as sound absorption, they lack strength and thermoformability because the skin material is laminated using an adhesive or the like. Furthermore, there is also the problem that the manufacturing process is complicated.

(Problems to be Solved by the Invention) The present invention solves the above problems, and its purpose is to provide a light 11 composite material that has excellent physical strength and formability, and is easy to manufacture. There is a particular thing.

(Means for Solving the Problems) The lightweight composite material of the present invention is composed of inorganic fibers and thermoplastic resin as main components. - A mat-like light composite material in which a layer of thermoplastic elastomer is laminated on a shaped molded article, the inorganic fibers being at least partially bonded to each other using the thermoplastic resin as a binder, The mat-like molded body has a large number of voids throughout, thereby achieving the above object.

Examples of the inorganic fibers used in the present invention include glass fibers and rock wool fibers, and the length thereof is preferably from 5 to 200 mm in terms of ease of forming a mat.
More preferably, the fiber contains 70% by weight of fibers having a diameter of 50 or more. The diameter of the inorganic fiber is preferably 5 to 20 μm, more preferably 9 to 17 μm. If the diameter of the inorganic fibers becomes too small, the mechanical strength will decrease, and if the diameter of the inorganic fibers becomes too large, the mat-like nonwoven fabric will become heavy, and the resulting composite material will have a large bulk density.

The above-mentioned inorganic fibers are made into a mat-like nonwoven fabric by any method. At this time, by mixing inorganic fibers with organic fibers made of thermoplastic resin, the bonding state between the inorganic fibers becomes good. As such organic fibers, polyethylene fibers, polyolefin fibers, etc. are used. The amount of organic fiber used is preferably 50% by weight or less based on the weight of the matte nonwoven fabric. An example of a method for producing a mat-like nonwoven fabric is a method in which inorganic fibers and, if necessary, organic fibers are supplied to a card machine, and the fibers are defibrated and mixed to produce a mat.

Further, in order to distribute the fibers in the thickness direction, it is preferable to perform needle punching. Needle punch is lam
It is preferable that the treatment is carried out at 30 to 60 locations, more preferably at 50 to 60 locations. The density of the mat-like nonwoven fabric is preferably from 0.04 to 0.1 g/am3, more preferably from 0.04 to 0, asg/cm3, since the density of the mat-like nonwoven fabric is preferably 0.04 to 0.1 g/cm3, and more preferably 0.04 to 0, asg/cm3.

The thermoplastic resin used in the thermoplastic resin film may be any resin that can be melted by heating and impregnated between inorganic fibers to bind the inorganic fibers to each other. For example, polyethylene, polypropylene, saturated polyester, polyamide,
Polystyrene, polyvinyl butyral, etc. are used. Preferably, the melt index (A
According to STM D1238, 230°C1 load 2.16
A resin having a low melt viscosity (measured in kg) of 10 or more is used. The thickness of the thermoplastic resin film is 50 to 2
00 μm is preferable, more preferably 100 to 150 μm
It is m. If the thickness of the thermoplastic resin film becomes too thick, the final composite material becomes heavy, and if it becomes too thin, the mechanical strength decreases.

As the resin constituting the thermoplastic elastomer, an elastic thermoplastic resin such as a soft vinyl chloride sheet is used. The thermoplastic elastomer is preferably a resin with high melt viscosity, particularly preferably a melt index of 1 or less.

The composite material of the present invention is manufactured as follows. First, a thermoplastic resin film is laminated on both sides of the above-mentioned matrix-like nonwoven fabric mainly composed of inorganic fibers, and a thermoplastic elastomer sheet is laminated on at least one side of this laminate. This laminate is heated to a temperature equal to or higher than the melting points of the thermoplastic resin and thermoplastic elastomer, and then compressed. Any method can be used to laminate the films. As for heating conditions, it is preferable to conduct the heating for 1 to 2 minutes at a temperature that is 50°C to 100°C higher than the melting point of the thermoplastic resin and thermoplastic elastomer. Further, any heating method may be employed, such as a method of heating the entire laminate in an oven, a method of radiant heating using a far-infrared heater, an infrared heater, or the like. Any compression method may be used, such as press compression, roll compression, etc. The compression conditions when employing the press compression method are preferably 0.1 to 5 kg/cm2, and the distance between a pair of rolls when compressing with rolls is preferably 5 to 15% of the thickness of the mat, and more preferably is 7-10%. The compression time is preferably 1 to 10 seconds. Further, if the thermoplastic resin is cooled and solidified during compression, the thickness of the mantle will not recover and the porosity will decrease, so it is preferable that the press mold and rolls are also heated to a predetermined temperature.

Since the thermoplastic resin melted by the heating has a low melt viscosity, it is impregnated into the mat-like nonwoven fabric, and when the resin is solidified, the inorganic fibers constituting the mat-like nonwoven fabric are bonded to each other. When the above-mentioned organic fibers are added to the mat-like nonwoven fabric, the organic fibers are also melted by this heating and the inorganic fibers are bonded to each other. By performing compression, the thermoplastic resin film effectively impregnates the mat-like nonwoven fabric, increasing the bonding strength between the inorganic fibers due to the thermoplastic resin.

The resulting resin-impregnated mat is maintained at the heating temperature and the pressure is released to restore its thickness. This creates voids within the mat, resulting in a lightweight composite material. Any method may be used to restore the thickness of the resin-impregnated mat, for example, the resin-impregnated mat is held for a predetermined period of time in a substantially non-pressurized state at a temperature equal to or higher than the melting point of the resin. The thickness of the mat returns to almost its original state mainly due to the elastic restoring force of the inorganic fibers, and voids are created within the mat. Usually, the bulk density of the resin-impregnated mat is 0.05~
It is desirable to restore the thickness to approximately O,Ig/c11'.

In the thus obtained composite material, the thermoplastic resin is uniformly dispersed in the mat-like nonwoven fabric mainly composed of inorganic fibers, and the inorganic fibers are at least partially bonded to each other. Because the thermoplastic elastomer has a high melt viscosity, it does not impregnate the inside of the mat, but when the compression is released, it settles on the mat surface and forms a surface layer. FIG. 1 shows a cross-sectional view of a composite material obtained by the method of the present invention. In FIG. 1, a composite material 1 has a plurality of inorganic fibers 2 made of thermoplastic resin 3.
are bonded together using an adhesive, and a thermoplastic elastomer layer 4 is laminated on a mat-like molded body having voids 5.

Since the composite material of the present invention has the above structure,
Lightweight and has excellent moldability. For example, the radius of curvature is 5m11
When hot press molding is performed using the drawing machine No. 1, a beautiful molded product without wrinkles can be obtained.

The physical strength is also comparable to similar composite materials in ponds. Furthermore, since the composite material of the present invention is integrally molded with a thermoplastic elastomer, there is no need to newly laminate a skin material, making it easy to manufacture.

Such a composite material can be suitably used as an interior member such as a ceiling material for an automobile.

(Example) The invention will now be described with reference to examples.

First, glass fibers with a length of 20 to 100 A+m and a diameter of 10 μm and polyethylene fibers with a length of 40 to 2001 I1 m and a diameter of 30 μm are supplied to a card machine at a weight ratio of 65:35, mixed and fiberized. It was made into a matte shape. This mat-like material was needle punched at a rate of 60 points per 112 ICl, and the thickness was 6 mm and the weight per unit area was 40.
A matte nonwoven fabric of 0 g/m2 was obtained.

A high-density polyethylene film with a thickness of about 130 μm is laminated on one side of this mat-like nonwoven fabric, and a high-density polyethylene film with a thickness of about 8 μm is laminated on the other side.
A 0 μl high-density polyethylene film and a pattern-printed colored olefin thermoplastic elastomer sheet having a thickness of about 200 μm were laminated so that the thermoplastic elastomer sheet was on the outside.

The high density polyethylene film used had a melt index of 20, and the thermoplastic elastomer sheet had a melt index of O11 or less. Melt index is 2.1 at 230°C according to ASTM DI238.
This is a value measured under the condition of 6 kg load. This laminate was sandwiched between Teflon belts, and hot air at 200°C was applied to melt the thermoplastic resin, and then the laminate was placed at 200°C, 13kg/0m.
Heat pressing was performed for 5 seconds under the conditions of 2. Next, by vacuum suctioning the upper and lower Teflon belts while maintaining the temperature at 200°C, the sheet thickness was restored to 6 mm to obtain a molded body made of the lightweight composite material of the present invention.

The obtained molded body was evaluated by the following method. After heating both sides of the molded body with an infrared heater at 200°C for 3 minutes,
It was supplied to a concrete mold with a textured surface with a depth of 10 mm, a distance between molds of 5 mm, and a concave curvature radius of 5I.
．． Breathe 15 for 1 minute at a pressure of 05~1kg/c+e2,
Performed deep drawing processing. The moldability was determined by measuring the radius of curvature of the concave part (the part corresponding to the convex part with a radius of curvature of 511111 of the mold) of the obtained molded product and visually determining the presence or absence of wrinkles in the deep drawn part. evaluated. moreover,
The strength of the molded product was evaluated by measuring the bending strength and bending elastic modulus (JIS [7221) of the flat portion (about 5 mm thick). These results are shown in Table 1 together with the results of Comparative Example 1 described below.

TomoΔTakumi clay The same matte nonwoven fabric as in Example 1 was coated on both sides with a thickness of about 1 mm.
A molded article was obtained in the same manner as in Example 1 by laminating 00 μm high-density polyethylene film (melt index: approximately 20). After heating both sides of the obtained molded body with an infrared heater at 200'C for 3 minutes, it was coated with a thickness of approximately 20'C.
A molded article was obtained by laminating 0 μl of a composite skin material of a thermoplastic elastomer sheet and a foamed polyethylene sheet. The obtained molded article was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

(Hereinafter, blank space) (Effects of the invention) The lightweight composite material of the present invention has excellent moldability,
Physical strength is also comparable to other similar composite materials. Furthermore, since the composite material of the present invention is integrally molded with a thermoplastic elastomer, there is no need to newly laminate a skin material (manufacturing is easy).

Therefore, the lightweight composite material of the present invention can be suitably used as an interior member such as a ceiling material for an automobile.

4. A day of ``'' FIG. 1 is a cross-sectional view of the composite material of the present invention.

1... Composite material, 2... Inorganic fiber, 3...
Thermoplastic resin, 4...Thermoplastic elastomer 5.
...Void.

that's all

Claims (1)

[Claims] 1. A mat-like lightweight composite material in which a layer of thermoplastic elastomer is laminated on a mat-like molded product mainly composed of inorganic fibers and a thermoplastic resin, the inorganic fibers binding the thermoplastic resin. 1. A lightweight composite material which is at least partially bonded to each other as materials, the mat-like molded body having a large number of voids throughout.