JPH0615180B2 - Method for manufacturing composite molded body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is suitably used as a composite molded article that is lightweight and has excellent sound absorption, rigidity, heat resistance, stain resistance, etc., especially as a molded ceiling material for automobiles. The present invention relates to a method for manufacturing a composite molded body.

[Prior Art] Conventionally, cardboards, glass fiber reinforced thermosetting resin sheets, etc. have been used as the base material for molded ceiling materials, which are one of the interior materials for automobiles, but cardboard has poor heat shaping properties. However, since it has no sound absorbing property and is hygroscopic, it has a drawback that it absorbs water and becomes heavy when used for a long period of time, and the thermosetting resin sheet has low sheet productivity and heat shaping property. It had the disadvantage of being bad and heavy.

Various proposals have been made to solve these drawbacks. For example, Japanese Utility Model Laid-Open No. 58-15035 discloses a laminate in which a glass fiber reinforced thermoplastic resin film is laminated on both sides of a styrene resin foam sheet. An automobile interior material in which a soft synthetic resin foam and vinyl chloride leather are sequentially laminated on one surface is described.

The above-mentioned interior material has excellent heat resistance and mechanical strength, but it is relatively heavy, has no sound absorption, and has the drawbacks of high cost. Further, JP-A-60-83832 discloses an automobile ceiling material in which a foam layer and a skin are laminated on a resin layer on a base material in which a thermoplastic resin layer is laminated on both sides of a glass fiber layer.

Although the above-mentioned base material is thin and has high mechanical strength and excellent heat formability, it lacks sound absorbing properties, heat insulating properties and the like.

Further, in order to improve the sound absorbing property, it has been proposed to laminate a sound absorbing material or to provide a through hole in the base material (JP-A-55-11947, JP-A-53-14074, JP-A-53-14074, However, there are drawbacks in that the manufacturing process is complicated and the cost is high, and that cigarette smoke and the like enter the through holes and stain the surface.

[Problems to be Solved by the Present Invention]

In view of the above drawbacks, the present invention produces a composite molded article that is excellent in heat resistance, mechanical strength, sound absorption, etc., is not easily polluted, is lightweight, has high productivity, is low in cost, and can be particularly suitably used as a ceiling material for automobiles. The purpose is to provide a method.

[Means for solving problems]

The mat-like material used in the present invention is mainly composed of inorganic fibers, and examples of the inorganic fibers include glass fibers,
Rock wool and the like are mentioned, and the length thereof is preferably 5 to 200 mm, more preferably 50 mm or more and 70% by weight or more from the viewpoint of forming a mat-like material. or,
The thickness is preferably 5 to 30 μm, more preferably 7 to 20 μm, because the thinner it is, the lower the mechanical strength is and the thicker it is, the heavier the bulk density is.

Any method may be adopted as the method for producing the mat-like material, for example, inorganic fibers are supplied to a card machine, and woven,
A method of mixing and weaving to produce a mat-like material can be mentioned.

Further, in order to bond the inorganic fibers, organic fibers or organic powders made of a thermoplastic resin such as polyethylene, polypropylene, saturated polyester, polyamide, polystyrene and polyvinyl butyral may be added.

Since the above-mentioned organic fibers and organic powders are for bonding the inorganic fibers, those having a melting temperature equal to or lower than the heating temperature for heating the laminated sheet are preferable.

Although it is preferable to add the organic fiber at the time of producing the mat-like material, the organic powder may be added at the time of producing the mat-like material or may be sprayed after producing the mat-like material. The organic powder may be used as a powder, or may be used as a powder dispersion or emulsion. Since the length and diameter of the organic fiber are preferably excellent when forming a mat-like material by mixing and weaving with the inorganic fiber, the length is 5
~ 200 mm is preferred, more preferably 20-100 mm
And the thickness is preferably 3 to 50 μm, more preferably 20 to 40 μm. The diameter of the organic powder is preferably 50 to 100 mesh when added in powder form,
It may be smaller when it is dispersed in a poor solvent or added as an emulsion.

Since the weight of the mat-like material increases as the amount of the organic fiber and powder added increases, it is preferably less than the weight of the inorganic fiber.

Needle punching may be carried out in order to improve the mechanical strength of the mat-like material. Needle punching is preferably carried out at 1 to 3 places per cm ² .

If the density of the mat-like material increases, it becomes heavier, and if it decreases, the mechanical strength decreases, so 0.01-0.2 g / Cm ³
Is preferred, more preferably 0.03 to 0.07 g / Cm
^{Is 3} .

The laminated sheet used in the present invention is one in which thermoplastic resin films having different melting temperatures of 10 ° C. or more are laminated on both surfaces of the mat-like material.

The above-mentioned laminated sheet is heated at a temperature not lower than the melting temperature of the thermoplastic resin having a low melting temperature in the laminated thermoplastic resin film and lower than the melting temperature of the thermoplastic resin having a high melting temperature, that is, the melting temperature. The thermoplastic resin film with a low melting temperature is melted, the thermoplastic resin film with a high melting temperature is not melted, and is compression-molded in a state where the film shape is maintained, and the thermoplastic resin film with a low melting temperature is impregnated into a mat-like material. Since many small holes are formed,
If the difference in the melting temperature is small, it becomes difficult to control the heating, and small holes are formed or not formed in both thermoplastic resin films. Therefore, the melting temperature of both thermoplastic resins is 1
It is necessary to differ by 0 ° C or more.

Examples of the above-mentioned thermoplastic resin film include films of thermoplastic resins such as polyethylene, polypropylene, polystyrene, and saturated polyester, which have melting temperatures of 10 or less.
Those that differ by ℃ or more are selected. When the organic fiber or powder is added to the mat-like material, it is preferable to use one having a melting temperature close to that of the thermoplastic resin film having a low melting temperature.

The thickness of the thermoplastic resin film becomes heavier as it becomes thicker, and the mechanical strength becomes lower as it becomes thinner, so that it is preferably 50 to 500 μm, more preferably 70 to 300 μm.
Further, when the organic fibers or powders are used together, the inorganic fibers are bonded by the organic fibers or powders, so that the thickness of the thermoplastic resin film can be reduced.

Any method may be adopted as a method of laminating the thermoplastic resin film, and examples thereof include a simple stacking method, a heat fusion method, and an extrusion laminating method.

In the present invention, the laminated sheet is a temperature above the melting temperature of the thermoplastic resin having a low melting temperature in the thermoplastic resin film laminated on both sides and lower than the melting temperature of the thermoplastic resin having a high melting temperature. After being heated at, it is compression molded. That is, since the thermoplastic resin film having a low melting temperature is compressed in a molten state, it is impregnated in the mat-like material to form a large number of small holes, and the thermoplastic resin film having a high melting temperature is not melted but is in a film state. Since it is compressed while maintaining the temperature, it can be adhered to the mat-like material in a film state without forming small holes. When the organic fiber or powder is added to the mat-like material, it is preferable to heat it within the above temperature range and above the melting temperature of the organic fiber or powder.

Further, any heating method may be adopted, and examples thereof include an overall heating method using a dryer, a radiant heating method using a far infrared heater, an infrared heater, and the like.

Although any method may be adopted for the compression molding, it is generally press-molded by a mold. The temperature at the time of compression molding may be lower than the melting temperature of the thermoplastic resin film having a high melting temperature, but if the temperature is high, small holes may be formed in the other thermoplastic resin film depending on the compression conditions. Therefore, it is preferably carried out at room temperature to 80 ° C. The compression pressure is preferably 0.2 to 50 kg / cm ² , and the compression time is preferably 10 seconds to 10 minutes.

When the composite molded body is used as a ceiling material for automobiles, it may be molded by laminating a cosmetic skin material such as vinyl chloride leather or a non-woven fabric on a thermoplastic resin film having a low melting temperature during compression molding. .

〔Example〕

 Next, examples of the present invention will be described.

Example 1 Glass fiber having a length of 40 to 200 mm and a diameter of 9 μm and a length of 4
A polyethylene fiber having a diameter of 0 to 200 mm and a diameter of 30 μm (melting temperature: 135 ° C.) was supplied to a card machine at a ratio of 65:35 (weight ratio), and mixed and woven to obtain a mat-like material with a thickness of 150.
μm polypropylene film (melting temperature 165 ° C.) and thickness 150 μm polyethylene film (melting temperature 13
5 ° C) is laminated on both sides of the mat-like material, thickness 10 mm, weight
A laminated sheet of 800 / g / m ² was obtained.

The obtained laminated sheet was supplied to a heating furnace at 150 ° C., heated, supplied to a mold (mold temperature 30 ° C.), and compression-molded at a pressure of 1 kg / cm ² for 1 minute to obtain a deformed shaped body. This mold has a minimum wall thickness of 2.9 mm and a maximum wall thickness of 8.0 mm, and the obtained molded product has almost this shape, and a large number of small holes are formed in the polyethylene film. The radius of curvature of the molded body corresponding to the portion where the radius of curvature of the mold is 5 mm is 5.
It was 4 mm.

The obtained molded body was cut into a rectangle of 1150 × 1400 mm, supplied to a hot air dryer set at 95 ° C., the four sides were held, and the heat-resistant displacement amount (hanging distance) after 24 hours was measured. In addition, a rectangular sample piece having a thickness of 6 mm and a size of 50 × 150 mm was prepared, placed on a pair of supports arranged at intervals of 100 mm, and the central portion was pressed at a speed of 50 mm / min to give a sample. The load when the piece was bent was measured to determine the bending strength and bending elastic modulus. Furthermore, the thickness is 8 mm and 500 x 500
mm sample piece was prepared and the sound absorption coefficient at 1000 Hz was measured by the normal incidence method, and the presence or absence of air permeability was measured.
The results of each measurement are shown in Table 1.

Example 2 A thermoplastic resin film having a thickness of 10 is laminated on a mat-like material.
0 μm polyester film (melting temperature 265 ° C.) and 150 μm thick polypropylene film (melting temperature 1
65 ° C.) and the temperature of the heating furnace was changed to 240 ° C., and the shape was almost the same as that of the mold in the same manner as in Example 1, and a modified shape in which many small holes were formed in the polypropylene film. Was obtained, the physical properties were measured, and the results are shown in Table 1.

Example 3 The same shape as the mold was carried out in the same manner as in Example 1 except that the weight of the mat-like material was changed to 700 g / m ² (the weight of the laminated sheet was 1000 g / m ² ). A dysmorphic form in which a large number of small holes were formed was obtained, the physical properties were measured, and the results are shown in Table 1.

Comparative Example A modified shape having substantially the same shape as the mold as in Example 1 except that the temperature of the heating furnace was set to 180 ° C., and a large number of small holes were formed in both the polyethylene film and the polypropylene film. Was obtained, the physical properties were measured, and the results are shown in Table 1.

[Effect of the invention] Since the method for producing the composite molded article of the present invention is as described above, the thermoplastic resin film is firmly adhered to both surfaces of the mat-like material mainly composed of inorganic fibers and has a low melting temperature. A composite molded article having a large number of small holes formed in the film can be easily obtained, and the obtained composite molded article is lightweight, low in cost, excellent in heat resistance, mechanical strength, sound absorption, etc. It has the advantage that it is unlikely to be contaminated with smoke, and can be suitably used as a ceiling material for automobiles, a building material, and the like.

Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area // B29L 9:00 4F

Claims (1)

[Claims] 1. A laminated sheet comprising a thermoplastic resin film having a melting temperature different by 10 ° C. or more, which is laminated on both surfaces of a mat-like material mainly composed of inorganic fibers, and having a melting temperature higher than that of a thermoplastic resin. , It is heated at a temperature lower than the melting temperature of the thermoplastic resin having a high melting temperature, compression molded at a temperature lower than the melting temperature of the thermoplastic resin having a high melting temperature, and a large number of small holes are formed in the thermoplastic resin film having a low melting temperature. A method for producing a composite molded article, which comprises: