JPH06134881A - Molding of fiber reinforced thermoplastic resin porous molded product - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] To improve the appearance and mechanical properties of fiber-reinforced thermoplastic resin porous molded products. [Structure] A thermoplastic resin film 2 is laminated on one side or both sides of a non-woven material 1 made of reinforcing fibers and a thermoplastic resin by a paper-making method, and then a plate-like body 3 is superposed on both sides of the non-woven material 1 and heat-treated. It is heated above the melting point or softening point of the plastic resin. Next, after the thermoplastic resin is pressed in a molten state, the pressure is removed while the thermoplastic resin is still molten to expand the nonwoven material 1 by spring back of the reinforcing fibers, thereby expanding the nonwoven material 1. The plate-like body is removed after pressurizing and cooling to a range that is less than the thickness and leaves a void to be included, and then molding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for molding a porous molded article of a fiber reinforced thermoplastic resin. The porous molded article according to the present invention can be widely used for industrial materials such as automobile parts, construction, and civil engineering, for which wood has been conventionally used.

[0002]

2. Description of the Related Art In recent years, due to global environmental problems, the cutting of South Sea timber has been regarded as a problem. Conventionally, Nanyo wood has been processed into plywood, and has been used in large quantities for vehicle materials such as buses and trucks, industrial materials such as construction and civil engineering, and development of alternative materials is desired.

As a wood substitute, a fiber-reinforced thermoplastic resin molded article composed of a relatively long reinforcing fiber and a thermoplastic resin has the characteristics that it is lightweight and has a relatively high strength.
It is attracting attention because it has rigidity. Since many of the wood substitutes are used as a plate, their mechanical properties such as bending strength and bending rigidity and weight reduction are important. In terms of material mechanics, bending strength is proportional to the square of the plate thickness, and bending rigidity is proportional to the cube of the plate thickness. As a method of utilizing the merit of improving mechanical properties and weight saving, a papermaking method (Japanese Patent Publication No. 52-12283) is used.
And Japanese Patent Publication No. 55-9119), a method for producing a porous molded article of a sheet-shaped molding material (JP-A-60-17).
9234 and JP-A-62-161529) have been proposed.

The sheet-shaped molding material is produced by applying a papermaking technique to uniformly disperse reinforcing fibers having a diameter of 3 to 30 μm and a length of 3 to 50 mm and a thermoplastic resin powder to produce a non-woven material. It is manufactured by using the material as a raw material, heating, pressurizing, and further cooling. The porous molded article is molded by utilizing the sheet expansion that occurs when the sheet-shaped molding material is heated to the softening point or the melting point or higher of the matrix thermoplastic resin before molding.

The non-woven material produced by the paper-making method has the property of being very bulky because the reinforcing fibers are dispersed in the form of monofilaments (single fibers). The thickness of the non-woven material varies depending on the content of reinforcing fibers, its shape, and papermaking conditions, but is about 10 times as thick as that of a sheet from which voids are generally used as a sheet-shaped forming material. The heating of the sheet-shaped molding material weakens the binding force of the thermoplastic resin to the reinforcing fibers, so that the residual stress of the reinforcing fibers is released, and the sheet-shaped molding material expands due to the springback to return to the original state.

This expanded sheet-shaped molding material is inserted into a molding die, and a clearance is set within the expanded sheet thickness and in a range where an enclosing void is left, and pressure is applied under the condition that a desired expansion ratio is obtained. By cooling and molding,
A porous molded article is manufactured. The porous molded article has a reduced strength per unit area and elastic modulus due to expansion, but the bending strength and flexural rigidity of the article are improved due to an increase in plate thickness.

However, in the porous molded article molded by the above-mentioned method, the appearance properties are deteriorated as described below, and the mechanical properties are not sufficiently improved. An example of a conventional method for forming a porous molded article is shown in FIG. Sheet-shaped molding material 9
Is generally heated in the far infrared heating furnace 10 to the softening point or melting point of the thermoplastic resin or higher. The expansion of the sheet-shaped molding material starts from the surface of the sheet that is first heated, and gradually expands as the heat reaches the center of the plate thickness. However, due to the expansion, a heat insulating air layer is formed inside the sheet, so that the thermal conductivity is reduced. For this reason, the degree of sheet expansion tends to be non-uniform, and the area near the surface becomes large and the inside becomes small (12, 13). In addition, since the sheet-shaped molding material expands under no load, unevenness on the surface 1
4 results. The unevenness of the surface portion occurs because the reinforcing fibers in the sheet-shaped molding material are randomly oriented, and springback occurs unevenly in the sheet. Further, on the seat surface, the reinforcing fibers are exposed by springback.
In addition, the thermoplastic resin deteriorates due to local heating accompanying a decrease in the thermal conductivity of the sheet, resulting in a marked deterioration in appearance. The plate-like bodies 3 are laminated on both sides of the expanded sheet-shaped forming material 11, inserted into the cooling press platen 7, and the clearance is set to be equal to or less than the expanded sheet thickness, and added under the condition of obtaining a desired expansion ratio. The porous molded product 16 is manufactured by pressure-molding, cooling-molding, and removing the plate-shaped body.

In this conventional molding method, the flow of the thermoplastic resin in the heated sheet-shaped molding material cannot be expected so much, and as a result, the appearance of the porous molded article inherits the appearance of the expanded heating sheet. Wrinkles 17 due to irregularities on the surface of the sheet, exposure 15 of reinforcing fibers, and deterioration of appearance due to thermal deterioration of the thermoplastic resin occur. Further, the sheet expansion becomes large in the vicinity of the surface and becomes small in the inside. Therefore, when the product is bent, the surface portion to which a tensile or compression load is applied has a mechanically weak structure and mechanical properties are deteriorated.

The deterioration of the appearance and mechanical properties is due to the adverse effect of the heat expansion of the sheet-shaped molding material, but this tendency is amplified as the initial thickness of the sheet becomes thicker. Thickness is limited and application is limited.

Further, the inventors of the present invention intend to improve the design of the porous molded article and expand the applications of the molded article, in order to apply the decorative treatment of the decorative pattern to the surface of the molded article, the uneven processing of the decorative pattern ( Hereinafter, a molding method using a plate-shaped body subjected to (texturing) was tried. That is, one of the plate-like bodies 3 to be superposed on both sides of the sheet-like molding material 11 expanded by heating in FIG. 3 is a plate-like body having a surface textured.

However, even when the textured plate-like bodies are overlapped with each other, in addition to the problem of deterioration of the appearance and mechanical properties described above, a molded product is formed from the textured plate-like body due to deterioration of the appearance of the sheet surface. It was recognized that it was difficult to obtain a good transfer of the makeup pattern to the surface.

[0012]

DISCLOSURE OF THE INVENTION The present invention provides a method for molding a fiber-reinforced thermoplastic resin porous molded article for the purpose of improving the appearance and improving the mechanical properties described above.

[0013]

The gist of the present invention is as follows. (1) A thermoplastic resin film is laminated on one or both sides of a non-woven material composed of reinforcing fibers and a thermoplastic resin by a paper-making method, and then a plate-like body is superposed on both sides of the non-woven material to melt the thermoplastic resin. Alternatively, after heating to a softening point or higher and applying pressure in a molten state of the thermoplastic resin, the pressure is removed while the thermoplastic resin remains in a molten state to expand the nonwoven material by springback of the reinforcing fibers, A method for molding a fiber-reinforced thermoplastic resin porous molded article, which comprises pressurizing and cooling to a range that is less than the expanded thickness of the nonwoven material and leaving an enclosed void, and then removing the plate-shaped body. (2) Molding of the fiber-reinforced thermoplastic resin porous molded article according to (1), wherein at least one of the plate-shaped bodies laminated on both sides of the non-woven material is subjected to unevenness processing (texturing) of a decorative pattern. Method. (3) The method for molding a fiber-reinforced thermoplastic resin porous molded article according to the above (1) or (2), wherein the thermoplastic resin film is a thermoplastic resin film containing 3 to 30% by volume of an inorganic filler.

An example of the method for molding the fiber-reinforced thermoplastic resin molded product of the present invention is shown in FIG. A thermoplastic resin film 2 is laminated preferably on both sides of a non-woven material 1 made of a reinforcing fiber and a thermoplastic resin produced by a paper-making method, and the non-woven material 1 having the film 2 laminated on both sides has a plate-like body 3 Are superposed and inserted into the heating press board 4, and heated until the thermoplastic resin is melted. After the thermoplastic resin is heated until it melts, the thermoplastic resin is impregnated between the reinforcing fibers, so that the pressure is applied at a pressure that does not cause fiber breakage (5). Subsequently, the pressure is removed while the thermoplastic resin is still molten, and the nonwoven material is expanded by the springback of the reinforcing fibers (6), and the expanded nonwoven material, the thermoplastic resin film, and the plate-like material are expanded. Under the condition that the body is overlapped, it is inserted into the cooling press platen 7 and the clearance is set to be equal to or less than the thickness of the expanded non-woven material and the space to contain the voids is left to obtain a desired expansion ratio. Pressurize, cool and mold,
The porous molded article 8 is molded by removing the plate-shaped body.

FIG. 2 shows another embodiment of the present invention.
It is intended to give a decorative pattern to a molded product. In the figure, the reference numerals common to those in FIG. In this example, as a plate-like body to be laminated on both sides of the nonwoven material 1 in which the thermoplastic resin film 2 is laminated, a decorative pattern is formed on the surface of the plate-like body 3A (on the upper side in FIG. 2) on the nonwoven material 1 side. The feature is that the plate-shaped body 3B on the other side (lower side) having a smooth surface is used. The other members and operations are exactly the same as in FIG. In this case, a porous molded product in which a decorative pattern is transferred to the surface of the molded product from one plate 3A is obtained. It is also possible to give a decorative pattern to both of the plate-shaped bodies.

The reinforcing fibers used as the raw material for the non-woven material include:
In addition to glass fiber, carbon fiber and metal fiber, inorganic fiber and organic fiber are used. The shape of the reinforcing fiber is preferably 3 μm or more in diameter from the viewpoint of easy handling and economical, and 30 μm or less in order to express sufficient strength, and the fiber length is 3 mm or more from the viewpoint of strength development and is uniform. It is desirable to set the thickness to 50 mm or less, which allows various dispersion. The reinforcing fiber is a water-soluble polymer for improving hydrophilicity for the purpose of good dispersion in water, a wetting agent, and a silane coupling agent for improving adhesiveness with the thermoplastic resin for expressing strength. For example, it is desirable to perform surface treatment.

The thermoplastic resin is polyethylene, polypropylene, polystyrene, styrene-butadiene-acrylonitrile copolymer, styrene-acrylonitrile copolymer, polyamide, polycarbonate, polyacetal, polyethylene terephthalate, polybutylene terephthalate, polyphenylene oxide, polysulfone, polyphenylene sulfide. Such as a plasticizer, a heat stabilizer, a light stabilizer, a filler, and the like, which also include a mixture of two or more of these resins.
It is also possible to add dyes and pigments, impact resistance agents, extenders, nucleating agents, processing aids and the like. The shape of the thermoplastic resin is appropriately selected from pellets, powders, flakes, and fibrous shapes.

The content of the reinforcing fiber is 10% by volume or more at which stable expansion due to springback occurs, and the reinforcing fiber and the thermoplastic resin can be adhered to each other to sufficiently exhibit the mechanical properties as a porous molded article. It is desirable to set the volume% or less.

The thermoplastic resin film to be laminated on the non-woven material is the same as the non-woven material thermoplastic resin because it is necessary to fuse with the fiber-reinforced thermoplastic resin of the core to form a porous molded article. Is generally used. However, heat resistance other than appearance improvement in the surface layer, surface hardness, when it is necessary to improve wear resistance, etc., a thermoplastic resin according to the purpose, a mixture with different resins, a laminated film composed of different resin films, Further, a thermoplastic resin film to which an inorganic filler is added may be used in consideration of the melting point and compatibility of the thermoplastic resin of the non-woven material.

As the inorganic filler added to the thermoplastic resin film, fine particle filler such as calcium carbonate and talc, flake filler such as mica, fibrous filler such as chopped glass fiber and rock wool fiber are used. The inorganic filler is preferably surface-treated with a silane coupling agent or the like in order to improve the adhesiveness with the thermoplastic resin for the purpose of developing strength. The inorganic filler is
It is appropriately selected according to the intended use of the molded product. When a smoother appearance of the molded product is required, it is preferable to use a fine particle filler having a diameter of 2 to 10 μm. In order to improve the strength of the surface of the molded product, the aspect ratio is increased with the aim of developing the reinforcing effect of the filler. Larger diameter 3 to ratio (fiber length / fiber diameter)
It is desirable to use a fibrous filler having a length of 30 μm and a length of 3 to 10 mm. Further, these inorganic fillers may be mixed and used in order to make the best use of the characteristics of both. Further, a laminated film of such a thermoplastic resin film containing an inorganic filler and a thermoplastic resin film may be used. The amount of the inorganic filler added is 3% by volume or more for the purpose of strengthening the thermoplastic resin, and 30% by volume or less that enables stable film formation. Depending on the thickness of the thermoplastic resin film or the application of the molded product, it is appropriately selected from the range of 0.03 to 1 mm.

As the plate-like member, the same one as in the manufacturing process of the sheet-like forming material is used. In the case of producing a sheet-shaped molding material, a nonwoven fabric material is laminated on both sides with a plate-like body having a smooth surface called a mirror plate, heated above the melting point or softening point of the thermoplastic resin, and then reinforced by pressing. A thermoplastic resin is impregnated between the two and further cooled to develop good adhesion between the reinforcing fiber and the thermoplastic resin. The material of the end plate is not limited as long as it can withstand the heating temperature, and examples thereof include metals, inorganic substances, and resins. These end plates need to have a property that the thermoplastic resin melts in the molten state but does not adhere in the non-molten state, and is coated with Teflon resin or the like in consideration of the releasability of the sheet-shaped molding material. In some cases, a release agent treatment of silicon or the like is performed.
When a decorative pattern is transferred to the surface of the molded product, at least one of the plate-shaped members is used which has a textured pattern such as a grain pattern or a leather pattern.

In the present invention, since the thermoplastic resin of the non-woven material is heated until it is melted, the thermoplastic resin is impregnated between the reinforcing fibers, so that the pressurization is performed at a pressure that does not cause fiber breakage. By improving the wettability of the reinforcing fibers and the thermoplastic resin in this step, the intersections of the reinforcing fibers that make up the porous molded article can be efficiently bonded with the thermoplastic resin, and good strength of the molded article can be expressed. You can

Subsequently, the pressure is removed while the thermoplastic resin is molten. The nonwoven material expands due to the springback of the reinforcing fibers. Since the reinforcing fibers are dispersed in the state of monofilament (single fiber) in the nonwoven material produced by the papermaking method, the nonwoven material is greatly expanded by springback. Further, since the non-woven material is heated uniformly by heating and pressurization, the thermoplastic resin does not deteriorate and the expansion becomes uniform.

The thermoplastic resin in the non-woven material is impregnated between the reinforcing fibers at the time of pressurization, but at the same time, the thermoplastic resin is leached at the interface with the plate-like material and is combined with the molten resin of the film existing at the interface. , Firmly fuse the two. Since the surface of the non-woven material expands in a state of being constrained by the surface of the plate-like body, unevenness of the sheet surface does not occur, the resin amount increases at the interface between the two, and the reinforcing fibers are covered with the resin. A resin rich layer is formed. The formation of this resin-rich layer also serves for good transfer of the decorative pattern on the surface of the plate-shaped body. When the content of the reinforcing fibers of the non-woven material is 30% by volume or more, the thermoplastic resin film is laminated so that the amount of the thermoplastic resin that oozes out is small, and therefore the effect of forming a stable resin-rich layer is obtained. Demonstrate.

On the other hand, stacking the textured plate-like bodies on the non-woven material has a beneficial effect in improving the appearance of the molded product, as compared with the case where the plate-like bodies having smooth surfaces are stacked. . The uneven shape of the plate-like body suppresses the movement of the reinforcing fibers of the non-woven material during pressurization, promotes the leaching of the thermoplastic resin to the interface, and helps form a stable resin-rich layer. Further, when the non-woven material is expanded, the uneven shape acts as an anchor, and there is an advantage that the restrained state between the non-woven material surface and the plate-like body surface is improved.

1 and 2, the molding method in which the thermoplastic resin film is laminated on both surfaces of the non-woven material has been described, but the lamination method is appropriately set according to the intended use of the molded product. That is, the thermoplastic resin film may be laminated on one surface of the non-woven material, or different thermoplastic resin films may be laminated on both surfaces of the non-woven material.

In the present invention, heating, pressing,
It is very effective from the viewpoint of productivity to use a double-belt conveyor type continuous press that continuously carries out the depressurization and cooling steps. An example of the molding method is shown in FIG.
The double belt conveyor type continuous press 18 comprises a pair of endless belts 19, each of which is a rotary drum 20, 21.
It is stretched by. Hydraulic ram 2 between rotating drums
A roller chain 23, 24, 25 connected to 2 is installed so as to be adjacent to the endless belt, and the distance between the endless belts and the pressing force are controlled. A heating plate 26 is installed inside the roller chains 23 and 24, and a cooling plate 27 is installed inside the roller chain 25.

The thermoplastic resin film 2 is laminated on both sides of the non-woven material 1 and inserted along the rotary drum 20. The endless belt is gradually narrowed until it reaches the roller chain 24, and the nonwoven material and the thermoplastic resin film are heated by the roller chain 23 until the thermoplastic resin is melted. Further, in the molten state of the thermoplastic resin, the roller chain 24 applies pressure to the reinforcing fibers so as to impregnate the thermoplastic resin with a pressure that does not cause fiber breakage. After this, the endless belt is stretched so as to have a wide interval until it reaches the rotary drum 21 from the roller chain 24 at a thickness less than the expansion thickness of the nonwoven material due to spring back. The nonwoven material expands immediately after passing through the roller chain 24. On the way, it is cooled by the roller chain 25, separated from the endless belt at the rotary drum 21, and the porous molded article 8 of the present invention is continuously molded.

When a double-belt conveyor type continuous press is used, the pair of endless belts serves as a plate. As the endless belt, a metal belt such as a steel belt is usually used, but it may be made of resin as long as it can withstand the heating temperature, and in consideration of releasability from the porous molded product, Teflon resin or the like is used. A coating may be applied or a release agent such as silicon may be treated.

Also in this method, the roller chain 2
At the time of pressurization of No. 4, the thermoplastic resin in the non-woven material leaches out to the interface with the endless belt, and together with the melted thermoplastic resin of the film present at the interface, both are firmly fused.
After that, since the non-woven material is uniformly expanded in a state of being restrained by the endless belt, a porous molded product having good mechanical properties and appearance can be obtained as in the molding method of FIG.

In the porous molded article of the present invention, by heating and pressing the non-woven material, the wettability of the reinforcing fiber and the thermoplastic resin is improved, and the thermoplastic resin is efficiently used at the intersection of the reinforcing fiber in uniform expansion. Bonded to improve mechanical properties.
Further, the thermoplastic resin in the non-woven material is impregnated between the reinforcing fibers at the time of pressurization, and at the same time, seeps into the interface with the plate-like body,
Together with the melted thermoplastic resin of the film existing at the interface, both are firmly fused. Since the surface of the non-woven material expands while being constrained by the surface of the plate-like body, and the interface between the two forms a stable resin-rich layer, wrinkles and reinforcing fibers are not exposed and a good appearance is obtained. Furthermore, when an inorganic filler-containing thermoplastic resin film is laminated, the surface layer of the porous molded article is reinforced by the filler, so that the surface hardness, abrasion resistance, etc. are simultaneously improved.

In the present invention, the permissible range of the thickness of the porous molded product is widened as compared with the conventional method, and it is useful as a method for molding a fiber-reinforced thermoplastic resin porous molded product by utilizing the merit of improving mechanical properties and weight saving. Results are obtained.

[0033]

【Example】

Example 1 A glass fiber having a diameter of 10 μm and a length of 13 mm as a reinforcing fiber and a spherical pellet having a diameter of 3 mm as a thermoplastic resin were mechanically crushed, and the crushed product was sieved to from 70 mesh (opening diameter 0.212 mm) to 10 mesh (opening diameter). Glass fiber content of 45% by weight (22.3% by volume) by a papermaking method using polypropylene resin powder classified to a diameter of 1.7 mm)
A non-woven material having a composition of 55% by weight (77.7% by volume) of polypropylene resin and a basis weight of 1100 g / m ² was produced.

The nonwoven material was cut into 600.times.2000 mm and laminated 7 sheets, and one polypropylene resin film (thickness: 50 .mu.m) was laminated on both sides thereof. Further, a stainless steel end plate as a plate-shaped body was superposed on both surfaces of this laminate, and a plate-shaped porous molded product was molded by the molding method shown in FIG. The laminated body was inserted into a heating press platen whose temperature was set to 210 ° C., and preheated under a pressure of 2 kgf / cm ² for about 7 minutes until the temperature of the central part of the nonwoven material increased to 190 ° C. or higher. . At this temperature, the polypropylene resin was sufficiently molten. Next, pressurize at a pressure of 5 kgf / cm ² for 1 minute,
Further, the laminate was inserted into a cooling press machine, the clearance of the press machine was set so that the thickness of the non-woven material was 12 mm, and the porous molded product was molded by cooling for about 5 minutes. The laminated body after the heating and pressurization immediately started to expand due to the springback of the reinforcing fibers within a short time when it was moved from the heating plate to the cooling plate, and the expanded thickness was about 20 mm. Further, it was confirmed that the nonwoven material after heating and pressurizing and the end plate were very strongly fused, and the surface of the non-woven material was expanded while being constrained by the surface of the end plate. After cooling, the end plate was removed to obtain a plate-like porous molded product having a plate thickness of 12 mm.

The surface of the porous molded product was rich in resin and wrinkled, and the reinforcing fibers were not exposed, and the product had a good appearance.
Further, by observation with an optical microscope and a scanning electron microscope, it was confirmed that the crossing points of the reinforcing fibers inside the porous molded article were efficiently adhered by the thermoplastic resin, and uniform expansion was performed. A test piece having a width of 70 mm and a length of 200 mm was sampled from the porous molded article and subjected to a three-point bending test with a span of 150 mm.
The results are shown in Table 1.

Example 2 The nonwoven material of Example 1 was cut into 300 × 300 mm pieces and laminated with seven sheets, and one polypropylene resin film (thickness: 50 μm) was laminated on both sides thereof. Further, a steel plate-like body having a grain pattern and a steel plate-like body having a texture pattern on both sides of this laminate are superposed on each other, and the method shown in FIG. A plate-like porous molded product having a plate thickness of 12 mm was molded under the same conditions as in 1.

The surface of the porous molded product was rich in resin, wrinkles were not exposed, and the reinforcing fiber was not exposed, and the appearance of the plate-shaped decorative pattern transferred to the molded product was good. Further, by observation with an optical microscope and a scanning electron microscope, it was confirmed that the crossing points of the reinforcing fibers inside the porous molded article were efficiently adhered by the thermoplastic resin, and uniform expansion was performed. A test piece having a width of 70 mm and a length of 200 mm was sampled from the porous molded article and subjected to a three-point bending test with a span of 150 mm. The results are shown in Table 1.

Example 3 The nonwoven material of Example 1 was cut into pieces of 600 × 2000 mm and cut into 7 pieces.
One sheet was laminated, and one sheet was laminated with a polypropylene resin film (thickness: 0.4 mm) to which 40% by weight of talc, which is a fine-particle inorganic filler having a diameter of 2 μm, was added. Further, a stainless steel end plate as a plate-like body was superposed on both surfaces of this laminate to form a plate-like porous molded article having a plate thickness of 12 mm in the same manner as in Example 1.

The surface of the porous molded article was completely covered with the talc-containing polypropylene resin layer, and wrinkles and reinforcing fibers were not exposed, and a good appearance was exhibited. Also, an optical microscope,
It was confirmed by scanning electron microscope observation that the intersections of the reinforcing fibers inside the porous molded article were efficiently adhered by the thermoplastic resin, and uniform expansion was performed. A test piece having a width of 70 mm and a length of 200 mm was sampled from the porous molded article and subjected to a three-point bending test with a span of 150 mm. The results are shown in Table 1.

Example 4 The nonwoven material of Example 1 was cut into pieces of 300 × 300 mm and laminated on seven sheets, and on one side thereof, one sheet of the talc-containing polypropylene resin film used in Example 3 was laminated. Furthermore, the film laminated side of this laminate is overlaid with a grained steel plate, and the other side is overlaid with a stainless steel end plate having a smooth surface as a plate,
A plate-like porous molded product having a plate thickness of 12 mm was molded in the same manner as in Example 2.

In the porous molded article, the film-laminated surface was completely covered with the talc-containing polypropylene resin layer, and the non-film-laminated surface was resin-rich,
No wrinkles or reinforced fibers were exposed on both surfaces, and a decorative pattern of a plate-like body was transferred to one surface of the surface of the molded product, and a mirror-like surface of the plate-like material was transferred to the other surface, showing a good appearance. Further, by observation with an optical microscope and a scanning microscope, it was confirmed that the intersections of the reinforcing fibers inside the porous molded article were efficiently adhered by the thermoplastic resin, and uniform expansion was carried out. A test piece with a width of 70 mm and a length of 200 mm was sampled from a porous molded product, and a span of 150 was obtained.
A 3-point bending test of mm was performed. The results are shown in Table 1.

Reference Example 1 The nonwoven material of Example 1 was cut into pieces of 600 × 2000 mm and cut into 7 pieces.
Sheets were laminated, and stainless steel end plates as plate-like bodies were superposed on both sides thereof to form a plate-like molded product with voids removed. The laminated body was inserted into a heating press platen whose temperature was set to 210 ° C., and preheated under a pressure of 2 kgf / cm ² for about 7 minutes until the temperature of the central part of the nonwoven material increased to 190 ° C. or higher. . Subsequently, pressure was applied at 5 kgf / cm ² for 1 minute, the laminated body was further inserted into a cooling press board, and pressure was applied at 5 kgf / cm ² for about 5 minutes to cool to form a plate-shaped molded article. . In this case, the clearance of the press platen was not set, and the non-woven material was cooled and molded in the state of being directly pressed, as in the heating and pressing. After cooling, the end plate is removed and the plate thickness is 6.1 mm
A plate-shaped molded product of

The surface of the plate-shaped molded product is resin-rich and wrinkles,
The reinforcing fibers were not exposed and had a good appearance. Further, by observation with an optical microscope and a scanning electron microscope, it was confirmed that the reinforcing fibers inside the molded product were uniformly dispersed, and the thermoplastic resin was sufficiently impregnated between them. A test piece with a width of 70 mm and a length of 200 mm was sampled from the molded product and span 1
A 50 mm 3-point bending test was performed. The results are shown in Table 1.

Comparative Example 1 A porous molded product was molded by the conventional method shown in FIG. 3 using the plate-shaped molded product molded in Reference Example 1 as a molding material.
The molded product of Reference Example 1 was cut into 600 × 600 mm, and the surface temperature was raised to 220 ° C. by a far-infrared heating furnace until it took about 7 minutes.
Heated for minutes. At this time, the molding material was greatly expanded in the vicinity of the surface, the inside was not sufficiently heated, and the thickness after expansion was about 15 mm. It was also confirmed that unevenness was generated on the surface portion, the glass fiber was exposed by spring back, and the polypropylene resin was thermally deteriorated by local heating. On both sides of the heated molding material, the grain-textured steel plate-like body used in Example 2 and the skin-pattern textured steel plate-like body are superposed and cooled. A porous molded article was molded by inserting the press molding machine into the press machine, setting the clearance of the press machine so that the thickness was 12 mm, and cooling for about 5 minutes. After cooling, the end plate was removed to obtain a plate-like porous molded product having a plate thickness of 12 mm.

Since the appearance of this porous molded article inherits the appearance of the heated molding material, wrinkles due to surface irregularities, exposed reinforcing fibers, and heat deterioration of the thermoplastic resin have occurred, and the surface of the molded article has changed from the plate-like body. No good transfer of the makeup pattern was obtained. Further, by observation with an optical microscope and a scanning electron microscope, it was confirmed that the inside of the porous molded product expanded greatly near the surface and the central part did not expand much like the original molding material. This center layer was about 50% of the initial thickness of the molding material and had a thickness of 3.2 mm. A test piece having a width of 70 mm and a length of 200 mm was sampled from the porous molded article and subjected to a three-point bending test with a span of 150 mm. The results are shown in Table 1.

In the porous molded articles of the examples, good mechanical properties were obtained because the intersections of the glass fibers were efficiently adhered with polypropylene resin and uniform expansion was performed. The strength and elastic modulus per area are lower than those of the non-expanded molded product of Reference Example 1, but the bending strength (bending load) and bending rigidity (elastic gradient) of the product are improved. . This result is because the bending strength is proportional to the square of the product plate thickness, and the bending rigidity is proportional to the cube of the plate thickness, and it was confirmed that the rigidity is remarkably improved.

In the porous molded articles of the examples, no obvious influence on the bending characteristics was observed depending on the type of the laminated thermoplastic resin film. The bending characteristics of the porous molded article were affected by the fiber-reinforced thermoplastic resin layer, which occupies the majority, and a correlation was found in the apparent density.

It was confirmed that the mechanical properties of Comparative Example 1 were lower than those of Example and Reference Example 1. In the porous molded article of Comparative Example 1, the expansion in the vicinity of the surface was very large, and the central portion showed a structure in which it was hardly expanded. Therefore, when the product is bent, the surface portion to which a tensile or compressive load is applied has a mechanically weak structure and mechanical properties are deteriorated. In order to develop good mechanical properties in the porous molded article of this method, it is necessary to avoid the adverse effect of heat expansion of the sheet-shaped molding material, and the initial thickness of the sheet-shaped molding material should be about 3 mm or less. desirable.

[0049]

[Table 1]

[0050]

Industrial Applicability The present invention provides a method for molding a porous molded article by a paper-making method as a method of utilizing the merit of improving the mechanical properties and weight saving of a fiber-reinforced thermoplastic resin. INDUSTRIAL APPLICABILITY According to the present invention, the mechanical properties and appearance of the porous molded product are improved, and the allowable range of the molded product thickness is widened as compared with the conventional method, so that it has a beneficial result in applications such as wood substitutes.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of a method for molding a fiber-reinforced thermoplastic resin porous molded article of the present invention.

FIG. 2 is a schematic view showing another example of the method for molding the fiber-reinforced thermoplastic resin porous molded article of the present invention.

FIG. 3 is a schematic view showing an example of a method for molding a conventional fiber-reinforced thermoplastic resin porous molded article.

FIG. 4 is a schematic view showing an example in which a double belt conveyor type continuous press is used in the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Non-woven material 2 Thermoplastic resin film 3 Plate-like body 4 Heating press board 3A Plate-like body 3A having a textured surface 3B Plate-like body having a smooth surface 5 Non-woven material in which a thermoplastic resin is pressed in a molten state 6 Nonwoven material uniformly expanded by spring back of reinforcing fiber 7 Cooling press board 8 Porous molded product of the present invention 9 Sheet-shaped molding material 10 Far-infrared heating furnace 11 Heated sheet-shaped molding material 12 Large expansion part 13 Small expansion part 14 Unevenness of seat surface part 15 Exposure of reinforcing fiber by spring back 16 Porous molded product 17 Wrinkled surface of molded product 18 Double belt conveyor continuous press 19 Endless belt 20.21 Rotating drum 22 Hydraulic ram 23, 24 , 25 Roller chain 26 Heating plate 27 Cooling plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takao Kimura 1 Toho-cho, Yokkaichi-shi, Mie Mitsubishi Petrochemical Co., Ltd. Yokkaichi Research Institute

Claims (3)

[Claims] A thermoplastic resin film is laminated on one or both sides of a non-woven material composed of reinforcing fibers and a thermoplastic resin by a paper-making method, and then a plate-like body is laminated on both sides of the non-woven material to form a thermoplastic resin. After heating above the melting point or softening point and applying pressure in the molten state of the thermoplastic resin, the pressure is removed in the molten state of the thermoplastic resin and the nonwoven material is expanded by the springback of the reinforcing fiber. And pressurize to a range that is less than the expanded thickness of the non-woven material and that leaves voids to be included,
A method for molding a fiber-reinforced thermoplastic resin porous molded article, which comprises cooling and molding and then removing the plate-shaped body. 2. The fiber-reinforced thermoplastic resin porous molded article according to claim 1, wherein at least one of the plate-like bodies laminated on both sides of the non-woven material is provided with a textured pattern (texture process) of a decorative pattern. Molding method. 3. The method for molding a fiber-reinforced thermoplastic resin porous molded article according to claim 1, wherein the thermoplastic resin film is a thermoplastic resin film containing 3 to 30% by volume of an inorganic filler.