JPH0776021A - Manufacture of porous molded body - Google Patents

Abstract

PURPOSE:To enable easy manufacture of a porous molded body being excellent in lightweight properties and rigidity by a method wherein a composite material is obtained by compressing a specific laminated body at a specific temperature and then releasing it from the pressure and then the porous molded body is obtained by expanding, molding and then cooling the composite material by using molding expansion dies. CONSTITUTION:A thermoplastic resin sheet A and a sheet B which can hold a prescribed form at a melting temperature of the sheet A or above are laminated on the opposite sides of a nonwoven mat-shaped material having inorganic fibers as main constituents, so that the sheet A is laid inside, and a laminated body thus obtained is compressed at a temperature which is a melting temperature of the thermoplastic resin sheet A or above and at which the sheet B can hold a prescribed form, and then released from the pressure, whereby a composite material is obtained. By using molding expansion dies made up of a female die 1 and a male die 2 having matched shapes, then, the composite material obtained is supplied, expanded and molded at the melting temperature of the thermoplastic resin or above and then cooled down, whereby a porous molded body is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a porous molded article which is suitable for use as a building material such as a ceiling material and a partition for automobiles.

[0002]

2. Description of the Related Art In general, building materials such as automobile ceiling materials and partitions are required to be lightweight and rigid.

As a method for producing these, Japanese Patent Laid-Open No. 64-7 has been used.
Japanese Patent No. 7664 discloses a method for producing a molded composite material by heating, pressurizing, and expanding a laminate in which a thermoplastic resin and a certain sheet are laminated on both surfaces of a mat-like material mainly composed of inorganic fibers. Is disclosed.

Further, in JP-A-4-34054, a laminate having a thermoplastic resin and a surface layer laminated on both surfaces of a mat-like material mainly composed of inorganic fibers is heated and pressed and then expanded. A method for producing a molded composite material by fusing and integrating a surface layer simultaneously with opening is disclosed.

However, in these methods, in order to obtain a molded product having a desired shape, it was necessary to reheat and press-mold, and heating and cooling had to be repeated.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method capable of easily producing a molded article excellent in lightness and rigidity.

The first step of the present invention will be described. The inorganic fibers used in the production of the non-fibrous mat-like material used in the present invention are not particularly limited, and general fibers can be used.

For example, glass fibers, carbon fibers, and ceramic fibers can be used.

If the length of the above-mentioned inorganic fiber is long, the inorganic fiber is wound around the card machine, which hinders the production of the non-woven mat-like product, and if the length is short, the density of the non-woven mat-like product obtained is
Since it becomes non-uniform, 10 to 200 μm is preferable.

The thickness of the inorganic fiber is such that the thicker the inorganic fiber, the more easily the inorganic fiber breaks during the production.
Since the mechanical strength of the obtained non-fibrous mat-like product decreases as the thickness decreases, it is preferably 3 to 30 μm.

If the amount of the inorganic fibers is large, the amount of the thermoplastic resin that binds the inorganic fibers to each other is small, and the strength of the resulting porous molded article is lowered. Since it decreases and the strength of the obtained porous molded product decreases, it is preferably 25 to 60% by weight of the porous molded product.

Furthermore, it is preferable to mix organic fibers such as synthetic fibers, vegetable fibers and animal fibers, because the resulting non-fibrous mat-like product can be made lighter. Examples of the synthetic fibers include aramid fibers, polyester fibers, polyethylene fibers, polypropylene fibers, rayon, vinylon, polyamide fibers and the like. As the plant fiber, cotton, hemp,
Examples include jute. As the animal fiber, silk,
Examples include wool.

The length of the organic fiber is preferably 10 to 200 μm for the same reason as the above inorganic fiber. In addition, the thickness of the organic fiber is preferably substantially the same as the thickness of the inorganic fiber used, because it is easily mixed with the inorganic fiber.

If the mixing amount of the organic fibers is large, the mechanical strength of the obtained non-fibrous mat-like product is lowered. Synthetic fiber,
The plant fiber and the animal fiber may be used alone or in combination.

As a method for producing a non-fibrous mat-like material using the above-mentioned inorganic fibers, a general method is used, and it is not particularly limited. For example, a needle punch method, a spun bond method, a thermal bond method and the like can be mentioned, and the needle punch method is particularly preferable.

When the needle punching method is used, if the number of needle punches is small, the strength of the obtained non-woven mat-like product is lowered, and if it is large, it is difficult to spread the composite material, and porous molding having a desired thickness is performed. Since it may not be possible to obtain a body, it is preferable to perform the treatment at 10 to 100 places per cm ² .

When the density of the non-woven mat-like material is high, the weight of the non-fibrous mat-like material to be obtained cannot be reduced, and when the density is low, the mechanical strength of the non-fibrous mat-like material is low.
01 to 0.2 g / cm ³ is preferable.

When the porosity of the non-woven mat-like material is low, the weight of the non-fibrous mat-like material obtained cannot be reduced, and when it is high, the mechanical strength of the non-fibrous mat-like material obtained is low.
0 to 98% is preferable.

In order to improve the binding property between the inorganic fibers, if necessary, an organic fiber, an organic powder, which has a melting temperature lower than the melting temperature of the thermoplastic resin used,
Alternatively, a dispersion or emulsion of organic powder may be added. Examples of the organic fibers and powders include organic fibers and powders made of polyethylene, polypropylene, polyethylene terephthalate, polyamide, polystyrene, polyvinyl butyral, or the like.

The dispersion or emulsion of the organic powder is added to the non-fibrous mat-like product after the production of the non-fibrous mat-like product. On the other hand, the addition of the organic fiber or the organic powder is not particularly limited as long as it is before laminating the thermoplastic resin sheet (A) on both surfaces of the non-woven mat-like material. Therefore, before producing the non-woven mat-like material, organic fiber or organic powder may be mixed with the inorganic fiber to produce the non-woven mat-like article, or after the non-woven mat-like article is produced. Alternatively, organic fibers or organic powder may be mixed with the non-fibrous mat-like material.

The length and thickness of the organic fiber are preferably 10 to 200 μm and the thickness is preferably substantially the same as the inorganic fiber for the same reason as the synthetic fiber. If the particle size of the organic powder is large, the dispersibility of the organic powder decreases, so 50 μm
It is preferably m or less.

The thermoplastic resin sheet (A) used in the present invention can be fused as long as it is capable of melting and binding the inorganic fibers to each other and melting at a temperature at which the above-mentioned inorganic fibers do not melt or deteriorate. Good and not particularly limited. Examples of such a sheet (A) include a sheet made of polyethylene, polypropylene, polyamide, polyethylene terephthalate, polystyrene, polyvinyl butyral, polyurethane or the like.

The sheet (A) is required to cover one surface of the non-woven mat-like material substantially uniformly.

Further, if the weight of the sheet (A) is small, the binding of the inorganic fibers to each other will be weakened and the mechanical strength of the resulting non-fibrous mat-like material will be reduced, and if it is large, it will be difficult to spread the composite material. Since it is not possible to obtain a porous molded product having a desired thickness, it is preferably 30 to 70% of the total weight of the non-woven mat-like material.

The sheet (B) used in the present invention is not particularly limited as long as it can maintain a certain shape at the melting temperature of the sheet (A) or higher. Examples of such a sheet (B) include a soft sheet made of iron, aluminum, copper or the like, a sheet made of polyethylene terephthalate, polybutylene terephthalate, polyamide or the like, a sheet made of paper and the like.

If the thickness of the above-mentioned sheet (B) is thin, the inorganic fibers used for the material of the non-fibrous mat-like material may damage the sheet such as perforation of the sheet (B). Since wrinkles may occur in the flexible molded product, the thickness is preferably 5 to 50 μm.

In the first step of the present invention, a constant shape can be maintained on both surfaces of the non-woven mat-like material containing inorganic fibers as a main component at a temperature not lower than the melting temperature of the thermoplastic resin sheet (A) and the sheet (A). The sheet (B) is laminated so that the sheet (A) is on the inner side, and the obtained laminate is at a temperature not lower than the melting temperature of the thermoplastic resin and at which the sheet (B) can maintain a constant shape. In this step, the composite material is obtained by compressing under pressure, impregnating the non-woven mat-like material with the thermoplastic resin, and then decompressing.

As a method for laminating the sheet (A) and the sheet (B) on both surfaces of the non-woven mat-like material, a general method can be used and is not particularly limited. For example, a method of simply placing the sheets on both sides of the non-woven mat-like material, a method of heat-sealing the non-woven mat and the sheet, a method of extrusion laminating the non-woven mat and the sheet, and the like can be mentioned.

When the sheet (A) and the sheet (B) are laminated on both sides of the non-woven mat-like material so that the sheet (A) is on the inner side, instead of the sheet (A) and the sheet (B) Using a laminated sheet in which the sheet (B) is laminated on one surface of the sheet (A) in advance, on both surfaces of the non-woven mat-like material,
You may obtain a laminated body by laminating | stacking a laminated sheet on both surfaces of a non-woven mat-like material so that the sheet (A) may face inside.

As a method for obtaining a laminated sheet by laminating the sheet (B) on one surface of the sheet (A), a general method can be used, and it is not particularly limited. For example, coextrusion is mentioned.

A general method is used for heating the laminate to a temperature not lower than the melting temperature of the sheet (A) and capable of maintaining the sheet (B) in a certain shape, and is not particularly limited. . For example, a hot air heating method, a radiant heating method using an infrared heater, a far infrared heater, or the like can be used.

As a method for compressing the laminate, a general method is used and is not particularly limited. For example, a method of compressing with a flat plate press, a method of compressing with a roll, and the like can be mentioned.
If the pressure for compression is small, the impregnation of the thermoplastic resin into the non-woven mat-like product will be insufficient, and even if it is increased, the effect of impregnating the thermoplastic resin into the non-fibrous mat-like product will not change. 1 to 20 kg / cm ² is preferable.

If the laminate after compression has a large thickness, the impregnation of the thermoplastic resin into the non-fibrous mat-like product will be insufficient,
It is preferable to compress so that the thickness is 4/5 or less of the thickness of the laminate before compression.

When the roll method is used, if the distance between the rolls is large, the impregnation of the thermoplastic resin into the non-woven mat-like product becomes insufficient, and if it is narrow, the inorganic fibers may be clogged between the rolls. Therefore, it is preferably about 4/5 to 1/20 of the thickness of the laminate.

The second step of the present invention will be described. The forming / expanding mold used in the second step of the present invention is not particularly limited as long as it is a mold having a structure capable of sucking both sides of the composite material and expanding the composite.

As a die having such a structure, for example, it is composed of two expansion plates, each expansion plate has a hole on the surface in contact with the composite material, and the composite material is sucked by vacuum suction from the hole. However, a mold having a structure capable of expanding the composite material can be used.

Here, expanding means that the both surfaces of the composite material are pulled or sucked in opposite directions to foam, thereby increasing the thickness of the composite material.

In the second step, the composite material is expanded at a melting temperature of the thermoplastic resin or above by using a mold expanding mold and then cooled,
It is a step of obtaining a porous molded body having a desired shape.

At this time, before or after the composite material is transferred to the mold expanding die, the composite skin material obtained by laminating the cosmetic skin plates on both surfaces of the composite material is expanded. You may expand using a metal mold and manufacture a porous molded object.

As the cosmetic skin plate, a general one is used and is not particularly limited. Examples of such a cosmetic skin plate include a non-woven fabric made of polyester fiber, a stretchable woven fabric, and a laminate of these with a foam.

If the foam is an open-cell foam made of urethane or the like, the skin composite material may not be sufficiently sucked in the expansion step of the skin composite material. A closed-cell foam made of, for example, is preferred.

When the composite material and the cosmetic skin plate are not heat-sealed to each other, the composite material and the cosmetic skin plate are adhered to each other.
It is necessary to provide an adhesive layer made of a hot melt adhesive or the like between the composite material and the cosmetic skin plate. Examples of the hot melt adhesive include polyethylene, polyisobutylene, polyamide, vinyl acetate-ethylene copolymer and the like.

When the composite material is expanded using a molding expansion mold, in order to improve the suction property of the composite material, the composite material is optionally compressed before expanding the composite material. The composite material may then be expanded.

If the suction pressure at the time of spreading is small, suction may not be possible, so 0.3 kg / cm ²
The above is preferable, and 0.5 kg / cm ² or more is particularly preferable.

When the composite material is expanded and molded to produce a porous molded body, if the thickness of the porous molded body is increased, the mechanical strength of the obtained porous molded body may decrease. It is preferable to expand and mold the composite material so that the thickness of the porous molded body is 10 times or less the thickness of the composite material.

A general method is used for cooling, and it is not particularly limited. For example, cooling by blowing air or cooling with cold air may be used.

The cooling may be performed after the expansion is completed, or the cooling may be performed at the same time as the expansion.

When cooling is performed simultaneously with the expansion, it is necessary to adjust the cooling so that the thermoplastic resin is melted until the expansion is completed.

[0048]

After the composite material is manufactured from the laminate, the composite material is kept warm as needed without cooling and reheating, and then the composite material is expanded and molded. The porous molded body is bound in the state of having voids and, if necessary, the cosmetic skin plate is fused and integrated.

[0049]

【Example】

(Example 1) A glass fiber having a length of 50 mm and a diameter of 10 µm and a polyethylene fiber having a length of 50 mm and a diameter of 30 µm were supplied to a card machine at a weight ratio of 2: 1 and defibrated, and then 80 per 1 cm ^2. Needle punching was performed at some points to obtain a non-woven mat-like material having a weight of 450 g / m ² .

The obtained non-fibrous mat-like material has a thickness of 12 on both sides.
Sheet of 0 μm high density polyethylene and thickness 1
A sheet of 0 μm polybutylene terephthalate was placed with the sheet of high-density polyethylene on the inside to obtain a laminate.

The obtained laminate was heated at 200 ° C. for 3 minutes and then heated at 200 ° C. using a flat plate press to obtain 5 kg /
It was compressed with a pressure of cm ² to obtain a composite material having a thickness of 0.7 mm.

Next, FIG. 1 shows a cross-sectional view of the molding and expanding mold used for molding the composite material. The forming and expanding mold comprises a female mold 1 and a male mold 2, each mold having a diameter of 10
Fourteen 14 mm vacuum holes 5 are provided at intervals of 20 mm, and the vacuum holes 5 communicate with the header 3 that communicates with a vacuum pump (not shown). Further, 4071 suction holes 6 having a diameter of 5 mm are communicated vertically from the vacuum holes 5 at intervals of 20 mm, and each of the molds 1 and 2 has a diameter of 5 mm.
Cooling holes 4 are provided at intervals of 100 mm.

Further, the female mold 1 of the molding expanding mold used.
The bottom portion 7 is a rectangle with one side of 1000 mm and 800 mm, the depth is 100 mm, and the length of the horizontal portion 9 is 20 mm.
0 mm, and the inclined portion 8 is 4 mm from the vertical plane.
It is inclined 5 °.

The male mold 2 of the molding expanding mold used is
It has a shape that matches the female die 1.

The obtained composite material was supplied to the above-mentioned forming and expanding die kept at 30 ° C. by water cooling, and the composite material was compressed to have a thickness of 1 mm, and then vacuum suction was performed at a pressure of 0.6 kg / cm ^2. Then, it was expanded to have a thickness of 4 mm, and allowed to cool in that state for 20 seconds to obtain a porous molded body.

The thickness, length, width and height of the obtained porous molded body were measured, and the results are shown in Table 1.

Comparative Example 1 A composite material obtained by the same method as in Example 1 was held at 200 ° C., a flat plate-like expanding plate was used to perform vacuum suction at a pressure of 0.6 kg / cm ² , and the thickness was reduced. 4m
It was spread so as to have a thickness of m and allowed to cool in that state for 20 seconds to obtain a plate-shaped molded body.

The obtained plate-shaped molded product was heated to 180 ° C. using an infrared heater, and a mold capable of molding a porous molded product having the same shape as that of Example 1 was used to perforate with a cooling press. A molded product was obtained.

The thickness, length, width, and height of the obtained porous molded body were measured, and the results are shown in Table 1.

Example 2 Instead of the sheet made of high-density polyethylene having a thickness of 120 μm and the sheet made of polybutylene terephthalate having a thickness of 10 μm laminated on both sides of the non-woven mat-like material, a sheet made of polyethylene having a thickness of 110 μm was used. A sheet made of polyethylene having an adhesive layer made of acid-modified polyethylene having a thickness of 10 μm and a sheet made of polybutylene terephthalate between the sheet and the sheet made of polybutylene terephthalate having a thickness of 10 μm, and a multilayer sheet integrally formed by coextrusion. A porous molded body was obtained in the same manner as in Example 1 except that a sheet made of polyethylene was laminated on both surfaces of the non-woven mat-like material so that the laminated body was obtained.

The thickness, length, width and height of the obtained porous molded body were measured, and the results are shown in Table 1.

Comparative Example 2 The same method as in Comparative Example 1 was carried out except that the laminate obtained in the same manner as in Example 2 was used.
A porous molded body was obtained.

The thickness, length, width and height of the obtained porous molded body were measured, and the results are shown in Table 1.

Example 3 Length 50 mm, Diameter 10 μm
Glass fiber and polyethylene fiber having a length of 50 mm and a diameter of 30 μm in a weight ratio of 2: 1 were fed to a card machine and disentangled, and then needle punching was performed at 80 points per 1 cm ² , and the weight was 450 g / m. It was obtained ² of the non-fiber mat-like material.

The obtained non-fibrous mat-like material has a thickness of 12 on both sides.
Sheet of 0 μm high density polyethylene and thickness 1
A sheet of 0 μm polybutylene terephthalate was placed with the sheet of high-density polyethylene on the inside to obtain a laminate.

The obtained laminated body was heated at 200 ° C. for 3 minutes, and then 5 kg /
It was compressed with a pressure of cm ² to obtain a composite material having a thickness of 0.7 mm.

On both sides of the obtained composite material, a polyethylene foam molded by co-extrusion lamination and composed of low density polyethylene and high density polyethylene mixed at a weight ratio of 70:30 and vinyl chloride were synthesized. A 3 mm-thick cosmetic skin plate made of synthetic leather made of polyethylene foam and vinyl chloride, having an amide hot melt adhesive layer between it and leather, was placed with the polyethylene foam inside. Then, a composite material in which a cosmetic skin plate was laminated on both surfaces of the composite material was obtained.

Next, using the molding and expanding mold used in Example 1, after compressing the composite material so that the thickness of the composite material was 2 mm, vacuum suction was performed at a pressure of 0.6 kg / cm ² to obtain the thickness. To 7 mm, and allowed to cool for 20 seconds in that state to obtain a porous molded body.

The thickness, length, width and height of the obtained porous molded body were measured, and the results are shown in Table 1.

(Comparative Example 3) The composite material obtained in Example 3 was kept at 200 ° C, and a flat plate-like spread plate was used to obtain a pressure of 0.
Vacuum suction was performed at 6 kg / cm ² , the material was expanded to have a thickness of 4 mm, and in that state, it was allowed to cool for 20 seconds to obtain a plate-shaped molded body.

The obtained plate-shaped molded product was heated to 180 ° C. by using an infrared heater, and then the cosmetic skin plates used in Example 3 were laminated on both sides of the plate-shaped molded product. The mold used in 1 was used to obtain a porous molded body with a cooling press.

The thickness, length, width and height of the obtained porous molded body were measured, and the results are shown in Table 1.

(Example 4) A porous molded body was obtained in the same manner as in Example 3 except that the laminate used in Example 2 was used.

The thickness, length, width and height of the obtained porous molded article were measured, and the results are shown in Table 1.

Comparative Example 4 A porous material was formed in the same manner as in Comparative Example 3 using the composite material obtained in the same manner as in Example 3 except that the laminate used in Example 2 was used. Got the body

The thickness, length, width and height of the obtained porous molded body were measured, and the results are shown in Table 1.

[0077]

[Table 1]

[0078]

The structure of the method for producing a porous molded article according to the present invention is as described above. According to the method for producing a porous molded article according to the present invention, heating, as in the conventional production method, It is not necessary to repeat cooling, the process can be simplified, and moreover, the same porous molded body manufactured by the conventional manufacturing method can be obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a mold expanding mold used in the present invention.

[Explanation of symbols]

 1 Female mold 2 Male mold 3 Header 4 Cooling hole 5 Vacuum hole 6 Suction hole 7 Bottom part 8 Slope part 9 Horizontal part

Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location D04H 1/42 K 7199-3B T 7199-3B 1/54 Q 7199-3B // B29L 9:00

Claims (1)

[Claims] 1. A thermoplastic resin sheet (A) and a sheet (B) capable of holding a constant shape at a melting temperature of the sheet (A) or higher, on both sides of the non-woven mat-like material containing inorganic fibers as a main component.
The sheet (A) is laminated so that the sheet (A) is on the inside, and the obtained laminate is compressed at a temperature that is equal to or higher than the melting temperature of the thermoplastic resin and the sheet (B) can maintain a constant shape, First step of pressing to obtain a composite material and using a molding expansion mold, the composite material is expanded at a melting temperature of the thermoplastic resin or higher,
A method for producing a porous molded body, comprising a second step of cooling after molding to obtain a porous molded body.