JPH0737080B2 - Method for producing composite molded article composed of thermoplastic resin and reinforcing fiber - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a composite molded article composed of a thermoplastic resin and a reinforcing fiber, and more particularly to a novel manufacturing method for molding pipes, rods and the like.

(Prior Art) Conventionally, pipes and the like made of fiber reinforced plastic (hereinafter referred to as FRP) use glass fibers, carbon fibers, and aramid fibers as reinforcing fibers, and heat of unsaturated polyester, vinyl ester, epoxy, etc. as matrix resin. Made with plastic resin. In general, a pipe or the like is formed by winding a filament (fiber) impregnated with a resin, an auxiliary agent, etc. around a rotating mandrel surface by a so-called filament winding method, and then heating this to cure the resin.

However, in this method using a thermoplastic resin, a curing agent, a catalyst, a monomer, or a solvent is mixed in the resin to be used, and the control of the pot life of the liquid resin thus mixed, the management of the viscosity, or the monomer is performed. However, there are many problems associated with the handling of liquid resins, such as the evaporation of solvents, and the curing time is long even during curing, resulting in extremely poor productivity.

(Object of the Present Invention) The present invention solves the above-mentioned problems caused by the conventional technique,
Another object of the present invention is to provide a method for producing a novel FRP molded product having excellent productivity.

(Structure of the present invention) That is, the gist of the present invention is to wind or knit a reinforcing fiber impregnated with a thermoplastic resin on a mandrel to make a preformed body, and to soften the thermoplastic resin from the preformed body. The present invention relates to a method for producing a composite molded article composed of a thermoplastic resin and a reinforcing fiber, which includes a step of heating the preformed body at a temperature equal to or higher than a temperature and a step of cooling the heated preform while pressurizing it in a mold.

As the thermoplastic resin used in the present invention, polyamide, polybutylene terephthalate, polycarbonate,
There are polyphenylene oxide, polyphenylene sulfide, polysulfone, polyether sulfone, polyether ether ketone, polyarylate, polyamideimide, liquid crystal polymer, polyoxybenzoyl and the like.
These thermoplastic resins are supplied in a molten state onto the reinforcing fibers, impregnated between the fibers by a pressure roller or a pressure belt, and continuously withdrawn. The fiber impregnated with the thermoplastic resin obtained is in the form of a sheet, a ribbon, or a strand.

The resin used in the present invention may be supplied to the reinforcing fiber as it is or as a solution obtained by modifying it and dissolving it in an appropriate solvent. In this case, the impregnated sheet is subsequently desolvated in the drying zone.

The reinforcing fibers used in the present invention are glass fibers, carbon fibers, boron fibers, aramid fibers, ceramic fibers, or composite fibers thereof, and are used for impregnating the thermoplastic resin with a cloth or filament.

Next, the manufacturing method of the present invention will be described in the order of steps. The first step is a step of winding or braiding fibers impregnated with a thermoplastic resin on a mandrel to form a preform. In this process, a normal filament winding device, a braider, or a sheet winding device is used. Further, in this step, locally heating the wound portion or the braided portion softens the fibers to facilitate winding, and prevents the wound fibers from being scattered. As the mandrel, metal, rubber, balsa material, synthetic resin foam or the like is used.

The second step of the present invention is a step of heating the preform obtained in the first step above the softening temperature of the thermoplastic resin. The softening temperature depends on the type of resin, for example, polyamide is 250 ° C, polybutylene terephthalate 220
℃, polycarbonate 150 ℃, polyphenylene oxide 140 ℃, polyphenylene sulfide 260 ℃, polysulfone 180 ℃, polyether sulfone 220 ℃, polyether ether ketone 290 ℃, polyarylate 180 ℃, polyamide imide 280 ℃, liquid crystal polymer 360 ℃, polyoxy Benzoyl 300 ℃ or more. The heating method is not particularly limited, and for example, a far infrared heater, an infrared lamp hot air oven, or the like is used. The heating step of this step can also be carried out in a mold.

The third step of the present invention is a step of cooling the heated preform while pressurizing it in the mold. The temperature of the mold in this step is below the softening temperature of the resin. If the mold temperature is lower, the cooling and solidifying speed of the resin will be faster and the molding time will be shortened, but for crystalline resin, avoid rapid cooling to increase the crystallinity. The optimum temperature is appropriately selected. The cooling time depends on the type of resin,
Although it depends on the mold temperature, it usually takes 30 seconds to 5 minutes, but the cycle time is shorter than that of thermoplastic resin.

In the present invention, heat treatment may be performed for the purpose of improving the dimensional stability and heat resistance of the obtained molded product.

(Example) Carbon fiber roving (3K) impregnated with polyphenylene sulfide was used as a thermoplastic resin. A metal cylinder having a length of 1000 mm and an outer diameter of 30 mm was used as the core metal. While rotating this core metal with an infrared lamp, rotate it at a speed of 50 rotations per minute, and the roving described above with a winding angle of ± 45 ° and a thickness of about
I wound it up to 2 mm. The obtained cylindrical molded product was placed in a heating furnace together with the cored bar, heated at 280 ° C. for 10 minutes, taken out of the heating furnace, placed in a mold at 50 ° C. and cooled under pressure. After 2 minutes, the core metal was taken out from the mold and the pipe having a smooth surface was obtained.

(Effect) According to the method of the present invention having the above-mentioned structure, a composite having excellent dimensional accuracy and high strength can be manufactured with high productivity. INDUSTRIAL APPLICABILITY The pipe and rod obtained by the present invention are usefully provided for applications requiring corrosion resistance, weight reduction, insulation and heat insulation.

Of course, the features of the present invention are also greatly expressed in process control, such as pot life control, viscosity control, as seen in thermosetting resins.
Furthermore, there is an advantage that it is not necessary to focus on management such as volatilization of the solvent.

Claims (1)

[Claims] 1. A step of winding or braiding a reinforcing fiber impregnated with a thermoplastic resin on a mandrel to form a preform, and heating the preform obtained in the step above a softening temperature of the thermoplastic resin. And a step of cooling the heated preform while pressurizing the heated preform in a mold, thereby producing a composite molded article of a thermoplastic resin and reinforcing fibers.