JPH07125082A - Manufacture of fiber reinforced molded product - Google Patents

Abstract

PURPOSE:To manufacture a fiber-reinforced molded product having a resistance to impact, and 4t superior surface appearance by incorporating a foaming agent in a fiber reinforced thermoplastic resin sheet, laminating a thermoplastic resin molded body thereon, heating a laminate up to the decomposition temperature of the foaming agent or over and fusion bonding and integrating the laminate. CONSTITUTION:Thermoplastic resin and a foaming agent in the powder form are fed into a fluidization tank 1 and formed into the fluidized state, and fiber 3 is passed through the tank in the parallel shape by using guide rolls 4 to turn into resin adhered fiber 5, which is then passed through between a couple of scrapers 6 to adjust the adhering quantity of the thermoplastic resin and the foaming agent. After that, the fiber is passed through heating rollers 7 heated up to the temperature lower than the decomposition temperature of the foaming agent, and the fiber is impregnated with the thermoplastic and the foaming agent, and the impregnated fiber is passed through cooling rolls 8 to manufacture a fiber reinforced thermoplastic resin sheet 9. The sheet 9 is drawn into a heated mold, and the foaming thermoplastic is extruded and coat laminated on one face of the sheet 9. Then the mold temperature is raised and foaming is carried out, and then cooled to manufacture a fiber reinforced molded product.

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 fiber reinforced molded article.

[0002]

2. Description of the Related Art A molded article made of a thermoplastic resin having a foamed body in an inner layer portion and a fiber reinforced portion in an outer layer portion is suitably used as an automobile part, a building material, a pipe material and the like. Japanese Unexamined Patent Publication (Kokai) No. 4-17952 discloses a technique for obtaining a fiber-reinforced molded product by stacking a fiber-reinforced thermoplastic resin sheet and a foamable thermoplastic resin sheet and subjecting them to stamping molding. This was mainly intended to reinforce the outside of the fiber-reinforced molded product to be molded to obtain a molded product excellent in mechanical strength by a simpler operation. However, the molded product obtained by such a manufacturing method has a sufficient impact resistance, but even if the fiber is exposed on the surface as it is, the appearance is not preferable, and the molded product is not suitable for a member in which design is important. It was something that could not be used.

[0003]

SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to provide a fiber reinforced molded article which has impact resistance and also has excellent surface appearance and designability.

[0004]

Means for Solving the Problems The gist of the present invention is that a fiber reinforced thermoplastic resin sheet contains a foaming agent in the production of a fiber reinforced molded article, and a thermoplastic resin molded body is laminated on the foamed agent. After that, it is heated to a temperature not lower than the decomposition temperature of the foaming agent to be fused and integrated.

The fiber-reinforced thermoplastic resin sheet of the present invention comprises
A thermoplastic resin containing fibers and a foaming agent. The thermoplastic resin is not particularly limited as long as it is melted and softened by heating, for example, polyethylene, polypropylene, polyvinyl chloride, polystyrene,
Examples thereof include polyamide, polyethylene terephthalate, polybutylene terephthalate, polycarbonate, polyvinylidene fluoride, polyphenylene sulphite, polyphenylene oxide, polyether sulfone and polyether ether ketone. Further, a copolymer containing them as a main component, a graft resin, may be a blended resin, for example, ethylene-vinyl chloride copolymer, vinyl acetate-ethylene copolymer, vinyl acetate-vinyl chloride copolymer, Examples thereof include urethane-vinyl chloride copolymer, acrylonitrile-butadiene-styrene copolymer, acrylic acid-modified polypropylene and maleic acid-modified polyethylene. Considering the method of using the fiber-reinforced molded article of the present invention,
Among these, recyclable materials such as polyolefin-based materials are particularly preferable. Stabilizers, lubricants, processing aids, plasticizers, colorants and the like may be appropriately added and blended with the thermoplastic resin.

The fiber is not particularly limited as long as it is thermally stable at any melting temperature of the thermoplastic resin constituting the fiber-reinforced thermoplastic resin sheet and the thermoplastic resin laminated later. Examples thereof include inorganic fibers such as glass fibers, carbon fibers, silicon / titanium / carbon fibers, boron fibers, and fine metal fibers; organic fibers such as aramid fibers, polyester fibers, and polyamide fibers. The length of the fibers used in the present invention can be appropriately selected according to the desired surface pattern, but in order to have sufficient impact resistance, it is preferably 5 mm or more.

The wire diameter of the above fiber used in the present invention is
If it is too short, the reinforcing effect cannot be exhibited, and if it is too long, the surface appearance is adversely affected. The amount of the fiber added can be appropriately selected depending on the required physical properties, but if it is too small, the surface impact resistance of the fiber reinforced molded product will not be sufficient, and if it is too large, a uniform fiber reinforced thermoplastic resin can be obtained. Therefore, 5 to 70 parts by weight is preferable for 100 parts by weight of the fiber-reinforced thermoplastic resin sheet.

The foaming agent is not particularly limited as long as the decomposition temperature is higher than the melting temperature of the thermoplastic resin forming the fiber reinforced thermoplastic resin sheet, and examples thereof include azodicarbonamide and azobisiso. Butyronitrile, N, N'-dinitropentamethylenetetramine,
p, p'-oxybisbenzenesulfonyl hydrazide,
Examples thereof include p-toluenesulfonyl semicarbazide, barium azodicarboxylate, trihydrazinotriazine, and 5-phenyltetrazole. The amount of the foaming agent added is too small to exert the effect of providing the design property, and if it is too large, the foaming of the fiber-reinforced thermoplastic resin sheet is too large and the impact resistance is poor and the design property is also hindered. Therefore, 0.05 to 100 parts by weight of the thermoplastic resin
0.5 parts by weight is preferred.

The method for producing the fiber-reinforced thermoplastic resin sheet is not particularly limited. For example, the fiber is dipped in a fluidized tank containing the thermoplastic resin and the foaming agent to adhere the thermoplastic resin and the foaming agent to the fiber, A method of producing a fiber-reinforced thermoplastic resin sheet by melting the thermoplastic resin with a heating roll or the like having a temperature not higher than the decomposition temperature of the foaming agent to integrate the fibers can be mentioned.

As the thermoplastic resin of the thermoplastic resin molded body on which the fiber reinforced thermoplastic resin sheet is laminated, the same thermoplastic resins as those described above as the thermoplastic resin constituting the fiber reinforced thermoplastic resin sheet can be mentioned. However, they may be of the same type or of different types. The thermoplastic resin molded body on which the fiber reinforced thermoplastic resin sheet is laminated has a proper capacity for the fiber reinforced molded article of the present invention by adding a foaming agent and a foaming auxiliary agent to make it foamable. It is possible to increase the utility value by further providing a crosslinking agent to increase the impact resistance, taking into consideration the use state of the fiber-reinforced molded article of the present invention, a stabilizer, a lubricant, a processing aid,
A plasticizer, a coloring agent and the like can be added as appropriate.

When the thermoplastic resin constituting the fiber reinforced thermoplastic resin sheet and the thermoplastic resin of the thermoplastic resin molded body on which the fiber reinforced thermoplastic resin sheet is laminated are resins having poor thermal bonding properties, A copolymer compatible with both is preferably used as an intermediate layer to be laminated. Examples of such a copolymer include an ethylene-vinyl chloride copolymer and a vinyl acetate-ethylene copolymer. The form of the thermoplastic resin molded body on which the fiber-reinforced thermoplastic resin sheet is laminated is particularly limited as long as the thermoplastic resin can be laminated so that the thermoplastic resin is present on the entire surface of the sheet after heating and fusion and integration. It may be in the form of a sheet, a pellet, a strand, or the like, instead of one. Further, the mode of lamination may be only one side or both sides of the fiber reinforced thermoplastic resin sheet.

The above laminate is heated above the decomposition temperature of the foaming agent to fuse and integrate with the thermoplastic resin, and at the same time, the surface of the fiber reinforced thermoplastic resin sheet is designed by combining the foamed portion and the fiber portion. It becomes a high pattern. At the same time, when the thermoplastic resin on which the sheets are laminated has foamability, it is molded into a desired shape by foaming, and is fused and integrated with the fiber-reinforced thermoplastic resin sheet to obtain the fiber-reinforced molded product of the present invention.

In the fiber-reinforced thermoplastic resin sheet used in the present invention, when the fibers are aligned in one direction, the surface pattern is similar to that of wood grain, and it is possible to express a design property excellent in wood texture. Such a fiber-reinforced thermoplastic resin sheet is prepared by placing the thermoplastic resin and the foaming agent in powder form in a fluidized tank, ejecting air from the bottom of the tank through the perforations to make them fluidized, and the fiber bundle is placed therein. The thermoplastic resin and the foaming agent are made to adhere by passing through while being arranged in one direction, and after adjusting the adhesion amount appropriately, they are guided to a heating roll and heated to impregnate the thermoplastic resin and the foaming agent into the fiber bundle. Then, it can be manufactured by guiding it to a cooling roll and cooling it.

[0014]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

Example 1 With the apparatus shown in FIG. 1, high-density polyethylene (average particle size 200 μm,
100 parts by weight of melting point 137 ° C. and 0.4 parts by weight of azodicarbonamide (decomposition temperature 208 ° C.) as a foaming agent were put into a powder form, and air was jetted from the porous plate 2 provided at the bottom of the tank to fluidize it. And a roving-like glass fiber bundle as the fiber 3 (monofilament diameter 23 μm
m, 4400 g / km) in parallel with the guide roll 4 to form the resin-adhered fiber 5, and then passed between a pair of scrapers 6 to adjust the gap between the thermoplastic resin and the foam. The adhesion amount of the agent was adjusted so that the weight ratio of the thermoplastic resin to the fiber was 1: 1. After that, the fibers are impregnated with the thermoplastic resin and the foaming agent by passing them through a heating roll 7 heated to a temperature lower than the decomposition temperature of the foaming agent, and the fibers are cooled by passing through a cooling roll 8 to have a width of 200 mm and a thickness of 0.
A 7 mm fiber-reinforced thermoplastic resin sheet 9 was obtained.

The fiber-reinforced thermoplastic resin sheet was drawn into a mold heated to 180 ° C., and 100 parts by weight of high-density polyethylene (melting point 137 ° C.) and azodicarbonamide (decomposed) were put into the mold from another extruder. A foamable thermoplastic resin consisting of 5 parts by weight of a temperature of 208 ° C. and 0.5 part of dicumyl peroxide was extruded and coated and laminated on one side of the fiber-reinforced thermoplastic resin sheet. The mold was heated to 210 ° C. to complete foaming and cooled to obtain a fiber reinforced molded product.

Comparative Example 1 A molded article was obtained in the same manner as in Example 1 except that the fiber and the foaming agent were not added. When the surfaces of the molded product of Example 1 and the molded product of Comparative Example 1 were observed with the naked eye, the molded product of Example 1 had a wooden texture and was excellent in aesthetic appearance. The molded product of No. 1 had no pattern and had no aesthetic appearance.

[0018]

According to the present invention, it is possible to obtain a fiber-reinforced molded article having impact resistance and design characteristics with excellent surface appearance.

[Brief description of drawings]

1 shows an apparatus for obtaining a fiber-reinforced thermoplastic resin sheet in Example 1. FIG.

[Explanation of symbols]

 1 Fluidized Tank 2 Perforated Plate 3 Fiber 5 Resin Adhesive Fiber 6 Scraper 7 Heating Roll 8 Cooling Roll 9 Fiber Reinforced Thermoplastic Resin Sheet

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location B29K 105: 08 B29L 9:00

Claims (1)

[Claims] 1. A thermoplastic resin molded article is laminated with a fiber-reinforced thermoplastic resin sheet containing a foaming agent, and the obtained laminate is heated to a temperature not lower than the decomposition temperature of the foaming agent to be fused and integrated. A method for producing a fiber-reinforced molded article, which comprises: