JPH0434054A - Production of porous composite material - Google Patents

Abstract

PURPOSE:To obtain the subject material having light weight, excellent rigidity, heat-resistance and formability and especially remarkably improved flexural strength and useful as a ceiling material for automobile by sandwiching an inorganic fiber and a resin material between plural sheet materials and heating the laminate at a specific temperature. CONSTITUTION:The objective material is produced by sandwiching (A) an inorganic fiber and (B) a resin material between (C) a pair of sheet materials, heating the laminate at a temperature to melt the component B and keep the component C in solid state, applying a pressure to both outer faces of the component C to impregnate the component B into the component A and expanding both outer surfaces of the component C to make the core layer composed of the component A and the component B to be porous and fusing and integrating the surface layers of the component C to both outer surfaces of the core layer.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing a porous composite material that is suitably used as a ceiling material for automobiles.

(Conventional technology) In general, automotive ceiling materials are lightweight, rigid, heat resistant,
Materials with excellent performance such as sound absorption and moldability are required.

Conventionally, as a method for manufacturing this type of material, a method as shown in, for example, Japanese Patent Application Laid-Open No. 64-77664 is known. That is, in this method, thermoplastic resin films are laminated on both sides of a mantle-like article mainly made of inorganic fibers to form a laminated sheet. On both sides of this laminated sheet, plate-like bodies are laminated on both sides of the laminated sheet, to which the thermoplastic resin is fused when it is molten, but not adhered when it is not molten. Next, the thermoplastic resin is heated to a temperature equal to or higher than the melting temperature of the thermoplastic resin, and the thermoplastic resin is compressed under pressure in a molten state, and then depressurized. Then, the thermoplastic resin is expanded in a molten state to increase the thickness of the laminated sheet, and then cooled. Thereafter, the plate-like body is peeled off to obtain a composite material.

Such a composite material is used by laminating a cosmetic skin material such as vinyl chloride leather or nonwoven fabric on its surface.

(Problem to be solved by the invention) As described above, in the past, the manufacturing process of composite materials and the laminating process of cosmetic skin materials were carried out separately, resulting in inconveniences such as poor productivity. .

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for producing a porous composite material in which the production of the composite material and the coating of a cosmetic skin material are carried out simultaneously.

(Means for Solving the Problems) The method for producing a porous composite material of the present invention includes a central layer in which inorganic fibers are bound together by a resin material with a large number of voids, and a core layer in which the resin material is in a viscous state. A method for producing a porous composite material comprising: a surface layer made of a sheet-like material that maintains a solid state at a temperature higher than that of the above-mentioned temperature; is heated at a temperature at which the sheet material becomes viscous or higher and maintains a solid state, and pressure is applied from both outer surfaces of the sheet material to impregnate the inorganic fibers with the resin material; By expanding both outer surfaces of a sheet-like material, a central layer made of inorganic fibers and a resin material is made porous, and a surface layer made of a sheet-like material is fused and integrated with both outer surfaces of the center layer. It is.

Examples of the above-mentioned inorganic fibers include glass fiber rock wool, ceramic fibers, carbon fibers, etc., and the length thereof is preferably 10 to 200 fi from the viewpoint of forming a molded body in the center layer, and 70% by weight of 5ON or more. It is more preferable that the above is included.

Further, the thickness is preferably 3 to 30 μm, more preferably 5 to 20 μm, because as the thickness becomes thinner, the mechanical strength decreases, and as the thickness becomes thicker, it becomes heavier and the density decreases.

The resin material may be any material that binds inorganic fibers together, and includes thermoplastic resins such as polyethylene, polypropylene, saturated polyester, polyamide, polystyrene, polyvinyl butyral, and polyurethane.

The forms of resin materials are fiber, powder, solution, suspension,
Any form such as an emulsion or a film can be used, and each is used in a suitable form depending on the method for manufacturing the porous composite material of the present invention.

The ratio of the above-mentioned inorganic fibers and resin material is 1:4 to 1:4 by weight, because when the amount of resin material decreases, the number of bonding parts decreases and the mechanical strength of the center layer decreases, and when it increases, the porosity decreases. 4:1 is preferred.

The surface layer is made of a substance that maintains a solid state at a temperature higher than the temperature at which the resin used for the center layer becomes molten. For example, when PE or PP is used for the center layer, the surface layer is polyamide, PET.

Examples include PBT. Further, a resin may be used for the center layer, and a metal plate such as paper, iron, aluminum, or copper, or a polyester nonwoven fabric or woven fabric may be used for the surface layer.

Next, an example of a method for manufacturing the porous composite material of the present invention will be described.

First, an inorganic fiber and a resin material are sandwiched between two sheet-like materials.

At this time, the inorganic fibers are formed into a mat shape.

Any method can be used to form the matte shape, such as supplying inorganic fibers to a card machine, defibrating and mixing them to produce a matte shape.

In addition, organic fibers and organic powders made of thermoplastic resins such as polyethylene, polypropylene, unsaturated polyester, polyamide, polystyrene, and polyvinyl butyral are added to bond inorganic fibers and to increase the density of mat-like materials. Good too. It is preferable to add the organic fibers when producing the mat-like product, but the organic powder may be sprinkled during the production of the cloak-like product or after producing the mat-like product. Further, the organic powder may be used as a powder, or as a powder dispersion or emulsion. The length and diameter of the organic fibers are preferably 5 to 200 m, more preferably 20 to 100 m because they have excellent formability when mixed with inorganic fibers to form a cloak-like object. Yes, thickness is 3-50μ
m is preferable, and more preferably 20 to 40 μm.

Further, the diameter of the organic powder is preferably 50 to 100 mesh when added in a powdered state, and may be smaller when added in a state dispersed in a poor solvent or in the form of an emulsion.

In addition, in order to improve the mechanical strength of the cloak-like article, needle punching may be performed, and it is preferable that needle punching is performed at 10 to 60 locations per 1 inch.

As the density of the mat-like material increases, it becomes heavier, and as it becomes smaller, the mechanical strength decreases, so it is 0.01 to 0.2 g/cd.
is preferable, more preferably 0.03 to 0.07 g/c
It is d. Further, the overall porosity is preferably 70 to 98%. Furthermore, the thickness of the mandrel-shaped material may be appropriately determined depending on the intended use, but is generally 2 to 200 m.

On the other hand, the resin material is supplied by laminating a thermoplastic resin film sheet on one or both sides of a cloak-shaped inorganic fiber.

Examples of the thermoplastic resin film include films of thermoplastic resins such as polyethylene, polypropylene, polystyrene, unsaturated polyester, polyurethane, polyvinyl butyral, and polyvinyl chloride. In addition, when adding organic fibers or powder to a mat-like material as an adhesive, it is preferable to use materials with a similar melting temperature.

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

Any method may be used to laminate the thermoplastic resin films, such as simply placing them, heat-sealing them, extrusion lamination, and the like.

Then, the inorganic fibers are impregnated with the resin material by heating at a temperature higher than the temperature at which the resin material melts and at which the sheet material remains solid, and by applying pressure from both outer surfaces of the sheet material.

At this time, any heating method may be used,
Examples include a hot air heating method, a radiant heating method using an infrared heater, a far-infrared heater, and the like.

Further, any method may be used to apply pressure, such as a pressing method, a method of compressing with a roll, etc. Press pressure is 0. 1 to 20 kg/aJ, and the total thickness of the center layer and surface layer is 41
It is preferable that the data be compressed by 5 or less, and the compression time may be several seconds. In addition, when compressing with rolls, the thickness between the rolls should be 415 to 1/20 of the total thickness of the center layer and surface layer.
It is preferable to set it to .

At this time, the molten thermoplastic resin is compressed under pressure and impregnated into the inorganic fibers. Next, when the pressure is released, the laminated sheet attempts to recover to its original thickness, but since the inorganic fibers have been crushed once, they do not recover sufficiently.

Therefore, by expanding both outer surfaces of the surface layer material in a state where the thermoplastic resin is molten, the thickness of the center layer made of inorganic fibers and resin material is increased and made porous, and both outer surfaces of the center layer are expanded. The surface layer made of sheet material is fused and integrated, and then cooled.

Then, since the center layer material is fused to the surface layer material, the thickness is restored and the thickness is increased. Note that at this time, since the thermoplastic resin is molten, the inorganic fibers and the bonded portions will not break.

The method of spreading may be carried out, for example, by holding both ends of the surface layer material or by pulling it in opposite directions by means of vacuum suction.

Cooling may be done by air cooling or by blowing cold air.

Note that cooling may be performed even when the expansion is in progress, but in that case, conditions must be set so that the thermoplastic resin remains molten until the expansion is completed.

By cooling and solidifying the thermoplastic resin, the desired composite material is obtained.

(Function) The method for producing a porous composite material of the present invention includes sandwiching an inorganic fiber and a resin material between two sheet-like materials, and heating the resin material at a temperature equal to or higher than the temperature at which the resin material is in a molten state and at which the sheet-like material is in a solid state. The inorganic fibers are impregnated with the resin material by applying pressure from both outer surfaces of the sheet-like material, and then both outer surfaces of the sheet-like material are expanded. As a result, the center layer made of inorganic fibers and resin material is bonded together with a large number of voids, and the surface layer made of sheet-like material is fused to both outer surfaces of the center layer. Become.

[First Example] Glass fibers with a length of 40 to 200 fl and a diameter of 9 to 13 μm were supplied to a card machine, mixed into a mat shape, and 1
(Needle punch 20 places per Jl! to a thickness of 1
A cloak-like article having a diameter of 0 MM and a weight of 600 g/rrr was obtained. Next, polyethylene sheets (thickness 100 μm
, weight 100 g/nf) were laminated to obtain a laminated sheet.

Straw paper with a thickness of 50 pm was laminated on both sides of the obtained laminated sheet and heated at 200° C. for 3 minutes. Then, with a clearance of 1.3 fi and a roll heated to 200°C,
After compressing at a speed of cm/sec, maintaining the temperature at 200°C, and expanding both surface layer materials by vacuum suction from both ends at a speed of 0.56/sec to restore the thickness of the laminated sheet to 9. A porous composite material was obtained by air cooling for a minute.

The composite material thus obtained was heated in the open at 200°C for 2 minutes, and then compressed in a mold at 30°C for 1 minute with a compression force of 1 kg/J to form a porous structure with steps as shown in Figure 1. A molded article 1 of the composite material was obtained.

The minimum thickness of the mold is 3.0 m, the thick part is 8.0 m, and the radius of curvature of the concave part is 5. The molded body 1 obtained has a length Li.
It took 202 days, width W900m, and step D20n.

As shown in FIG. 2, this molded body 1 was cut into a long plate shape having a width of 50 days to obtain a test piece 10. And this 100m
A load G is applied from above the center position of the test piece A, and a bending load (kg 15 cm) is applied just before the test piece lO breaks.
width) was measured. The results are shown in Table 1.

[Second Embodiment] In place of the straw paper used in the first embodiment, a sheet with a thickness of about 21 (30
A porous composite material was obtained in the same manner as in Example 1 above, except that a polyester nonwoven fabric with a weight of 0g/rrr> was used. Further, a molded body was molded in the same manner as in the first example, and the bending load was measured. The results are shown in Table 1.

[Third Example] A porous composite material was obtained in the same manner as in the first example except that aluminum foil with a thickness of 30 μm was used in place of the straw paper used in the first example. Moreover, the compression force of the first embodiment is 1 kg/d! The weight was changed from 1 to 7 kg/-, and the other conditions were the same as in the first example to form a molded body, and the bending load was measured. The results are shown in Table 1.

[Comparative example]

The straw hanshi of the first embodiment was not used, and the others were used in the first embodiment.
A porous composite material was obtained in the same manner as in the example. Further, a molded body was molded in the same manner as in the first example, and the bending load was measured. The results are shown in Table 1.

Table 1 Decreasing Margin) (Effects of the Invention) As described above, according to the present invention, the central layer made of inorganic fibers and resin material is bound together with a large number of voids, and both sides of the central layer Since the surface layer made of sheet-like material is fused and integrated with the outer surface, it is possible to easily produce porous composite materials that are lightweight, have excellent rigidity, heat resistance, and shapeability, and in particular have significantly improved bending strength. can do.

In addition, since both surface layers are manufactured in a state where they are fused and integrated, there is almost no scattering of inorganic fibers, which is excellent in terms of environmental hygiene.

Furthermore, if both surface layers are paper, synthetic fiber woven fabric, or non-woven fabric,
It can be molded into a predetermined shape by shaping and pressing after heating,
In the case of a metal plate, it is possible to shape it without any special heating.

Of course, shaping becomes easier if the center layer is melted by heating.

[Brief explanation of drawings]

Figure 1 is a perspective view schematically showing the overall structure of a molded body made of a porous composite material molded in the first to third examples, and Figure 2 is a bending load applied to the molded body. FIG. 2 is a schematic diagram showing the test method. 1... Molded body (method for manufacturing porous composite material)

Claims (1)

[Claims] 1) A central layer in which inorganic fibers are bound by a resin material with a large number of voids, and a sheet-like material that maintains a solid state at a temperature higher than the temperature at which the resin material becomes molten. A method for producing a porous composite material comprising a surface layer consisting of an inorganic fiber and a resin material sandwiched between two sheet-like materials, the temperature at which the resin material melts or higher, and the sheet-like material By heating at a temperature that maintains a solid state and applying pressure from both outer surfaces of the sheet-like material to impregnate the inorganic fibers with the resin material, expanding both outer surfaces of the sheet-like material, A method for producing a porous composite material, which comprises making a center layer made of inorganic fibers and a resin material porous, and integrating surface layers made of a sheet-like material by fusing on both outer surfaces of the center layer.