JPH10329190A - Method for producing fiber-reinforced thermoplastic resin molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-strength fiber-reinforced thermoplastic resin molded article in which reinforcing fibers remain for a long time after extrusion molding and are dispersed and adhered to a thermoplastic resin of a matrix in monofilament units. Provided is a method for producing a reinforced thermoplastic resin molded article. SOLUTION: The method for producing a fiber-reinforced thermoplastic resin molded body is a method of impregnating a thermoplastic resin D or a thermoplastic resin D containing a modified thermoplastic resin C, which is impregnated between monofilaments of reinforcing fibers. Fiber R or S
Is an extruder in a state where the thermoplastic resin B is kneaded and melted.
It is supplied from the reinforcing fiber supply port 23 into the inside 21. Thermoplastic resin B
The method includes a step of mixing a thermoplastic resin-impregnated reinforcing fiber R or S therein and then passing the mixture through an extrusion mold 22 to obtain a molded body. When a high-viscosity thermoplastic resin is used, it is used in the form of a powder so as to penetrate between the monofilaments of the reinforcing fibers.

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 thermoplastic resin extrudate comprising a thermoplastic resin reinforced by reinforcing fibers.

[0002]

2. Description of the Related Art Conventionally, for example, in an extrusion molding method for producing a long thermoplastic resin molded body, a method of simultaneously melting and kneading a thermoplastic resin and a reinforcing fiber in an extruder to enhance the strength of the molded body has been used. Have been.

However, when this method is used, the thermoplastic resin as a matrix is strengthened by the reinforcing fibers, but the degree of strength improvement is small. This is due to the fact that the reinforcing fibers are cut by pressure and shear.

In extrusion molding, a thermoplastic resin having a higher viscosity than that used for injection molding is used in order to prevent drawdown. An increase in the shearing force applied to the reinforcing fibers was also one of the causes of shortening the residual fiber length after extrusion molding.

As a method of reducing the cutting of the reinforcing fibers in the extruder, there is a method of reducing the volume compression ratio of the screw as much as possible. In such a method, the reinforcing fibers are contained in a thermoplastic resin as a matrix. There has been a problem in that the binder is not sufficiently dispersed or the binder used for bonding the reinforcing fibers is not sufficiently charged and decomposed during kneading, and impregnation failure of the thermoplastic resin occurs.

[0006] In order to solve such a problem of the prior art, a method described in Japanese Patent Application Laid-Open No. 57-181852 has been proposed. In the previously proposed method, heat is drawn while drawing continuous fibers. Thermoplastic resin impregnated reinforcing fibers obtained by a method of impregnating a thermoplastic resin have been used.

[0007] That is, in the previously proposed method, the reinforcing fiber preliminarily melt-impregnated with the thermoplastic resin alone or a mixture of the reinforcing fiber preliminarily melt-impregnated with the thermoplastic resin and the thermoplastic resin is supplied to the extruder. By using the method, the necessity of impregnation in the screw can be eliminated, so that the volume compression ratio of the screw can be reduced, and the cutting of the reinforcing fibers can be prevented.

[0008]

However, although the volume compression ratio can be reduced by using the above-mentioned proposed method, the unmelted thermoplastic resin in the screw and the reinforced fiber impregnated with the thermoplastic resin can be used. And contact with each other or interfere with each other to cause mechanical breakage of the reinforcing fibers.

In the above-mentioned method, the viscosity range of the thermoplastic resin that can be impregnated into the reinforcing fibers is limited.
The relatively high-viscosity thermoplastic resin used for extrusion molding is
There is a problem that it is difficult to impregnate the reinforcing fiber, and if the impregnation is attempted forcibly, the reinforcing fiber is cut.

An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a high-strength fiber-reinforced heat-resistant fiber in which reinforcing fibers remain long after extrusion molding and are dispersed and adhered to the thermoplastic resin of the matrix in monofilament units. It is an object of the present invention to provide a method for producing a fiber-reinforced thermoplastic resin molded article capable of obtaining a plastic resin molded article.

[0011]

Means for Solving the Problems To achieve the above object, the invention according to claim 1 of the present invention is a method for producing a fiber-reinforced thermoplastic resin molded article, wherein the thermoplastic resin A is made of a reinforcing fiber. The thermoplastic resin impregnated reinforcing fiber R impregnated between the monofilaments is supplied into an extruder in a state where the thermoplastic resin B is kneaded and melted, and the thermoplastic resin impregnated reinforcing fiber R is mixed into the thermoplastic resin B. And thereafter, passing through an extrusion die to obtain a molded body.

Next, the invention according to claim 2 of the present invention provides
A method for producing a fiber-reinforced thermoplastic resin molded article, wherein a thermoplastic resin D containing a modified thermoplastic resin C to which a carboxylic acid derivative is bonded is impregnated between monofilaments of the reinforcing fiber. S is supplied into the extruder in a state where the thermoplastic resin B is kneaded and melted,
It is characterized by including a step of mixing a thermoplastic resin-impregnated reinforcing fiber S into a thermoplastic resin B and then passing the mixture through an extrusion die to obtain a molded body.

Here, the extruder has a volume compression ratio of 2.0.
A single screw extruder equipped with the following screws is preferred.

That is, in this case, the invention according to claim 1 or 2 is a method for producing a fiber-reinforced thermoplastic resin molded article, wherein the thermoplastic resin A or D is impregnated between monofilaments of reinforcing fibers. The thermoplastic resin-impregnated reinforcing fibers R or S are supplied into a single-screw extruder in a state where the thermoplastic resin B is kneaded and melted, and is heated by a screw having a volume compression ratio of 2.0 or less in the single-screw extruder. The method is characterized by including a step of mixing a thermoplastic resin-impregnated reinforcing fiber R or S into a plastic resin B and then passing the mixture through an extrusion die to obtain a molded body having a desired cross-sectional shape.

The invention according to claim 3 of the present invention relates to a method for producing a fiber-reinforced thermoplastic resin molded product, wherein a powdery thermoplastic resin A or D is placed in a fluidized state in a tank. A continuous monofilament bundle is introduced, and while the monofilament bundle is unraveled in the tank, the thermoplastic resin impregnated reinforcing fibers U obtained by impregnating the powdery thermoplastic resin A or D between the monofilaments are mixed with the thermoplastic resin B. Is supplied to the extruder in a state where the thermoplastic resin B is kneaded and melted.
The method is characterized by including a step of mixing a thermoplastic resin-impregnated reinforcing fiber U therein and then passing the mixture through an extrusion die to obtain a molded body.

Here, the extruder has a volume compression ratio of 2.0
A single screw extruder equipped with the following screws is preferred.

That is, in this case, the invention according to claim 3 is a method for producing a fiber-reinforced thermoplastic resin molded article,
A continuous monofilament bundle is introduced into a tank in which the powdery thermoplastic resin A or D is kept in a fluidized state,
While the monofilament bundle is unraveled in the tank, the thermoplastic resin impregnated reinforcing fibers U formed by impregnating the powdery thermoplastic resin A or D between the monofilaments are mixed with the thermoplastic resin B in a molten state. The mixture is supplied into a screw extruder, and in a single screw extruder, the thermoplastic resin impregnated reinforcing fiber U is mixed into the thermoplastic resin B by a screw having a volume compression ratio of 2.0 or less, and then passed through an extrusion die. Thus, the method includes a step of obtaining a molded body having a desired cross-sectional shape.

Next, the reinforcing fibers will be described.

As the reinforcing fibers used in the method of the present invention, those which do not melt-soften and carbonize by the heat applied in the production process can be used. Specifically, glass fibers, carbon fibers, metal fibers, and aramid fibers are used. Organic fibers such as fibers, polyester fibers and polyamide fibers; and natural fibers such as silk, cotton and hemp.

The form of the reinforcing fibers may be a bundle of melt-spun monofilaments having a small fiber diameter, or a strand of monofilaments bound with a binding agent or the like for easy handling.

The monofilament of the reinforcing fiber has a diameter of 1
To 50 μm, particularly preferably 3 to 23 μm. When the diameter of the monofilament is smaller than 1 μm, the reinforcing effect by the reinforcing fiber is small. If it is larger than 50 μm, the contact area between the thermoplastic resin and the fiber is smaller than that of a small-diameter monofilament of the same type and the same weight, so that the reinforcing effect by the reinforcing fiber is small.

Next, the thermoplastic resin will be described.

The thermoplastic resins A, B, and D used in the method of the present invention are not particularly limited as long as they are resins that can be formed by extrusion, and include polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyamide, and polyethylene terephthalate. , Polybutylene terephthalate, polycarbonate, polyvinylidene fluoride, polyphenylene sulfide, polyphenylene oxide, polyether sulfone, polyether ether ketone, polymethyl methacrylate and the like.

Further, a copolymer or a graft polymer resin containing the above-mentioned thermoplastic resin as a main component, for example, chlorinated polyvinyl chloride, ethylene-vinyl chloride copolymer, vinyl acetate
Ethylene copolymer, vinyl acetate-vinyl chloride copolymer,
Urethane-vinyl chloride copolymer, acrylonitrile-butadiene-styrene copolymer, acrylonitrile-styrene copolymer, silane-modified polyethylene, carboxylic acid-modified polyethylene, carboxylic acid-modified polypropylene and the like can also be used. Further, rubber, elastomer and crosslinkable resin can also be used.

Considering the molding temperature, 120-250 ° C.
Polyethylene, which can be molded at relatively low temperatures such as
It is preferable that the main component is polypropylene, polyvinyl chloride, polystyrene, acrylonitrile-butadiene-styrene copolymer, or the like.

As the modified thermoplastic resin C, a thermoplastic resin in which a carboxylic acid derivative is copolymerized or graft-polymerized in a main chain or a side chain can be used. These modified thermoplastic resins can be obtained by supplying a carboxylic acid derivative when polymerizing the thermoplastic resin and copolymerizing it, or by graft-polymerizing the carboxylic acid derivative onto the thermoplastic resin. As a method of graft-polymerizing a carboxylic acid derivative to a thermoplastic resin, a method of supplying a carboxylic acid derivative together with a polymerization initiator or a chain transfer agent to the thermoplastic resin,
After supplying the carboxylic acid derivative to the thermoplastic resin, a method of activating the polymer chain of the thermoplastic resin by using light or radiation to cause a reaction and the like can be mentioned.

Here, the carboxylic acid derivative is an ester,
Refers to carboxylic anhydride, carboxylic amide, acyl halide and the like. As the carboxylic acid, maleic acid,
Fumaric acid, acrylic acid, methacrylic acid and the like.

Since the modified thermoplastic resin obtained by the above-described method has a large polarity and good adhesion to reinforcing fibers, the obtained fiber-reinforced thermoplastic resin molded article has high strength.

The thermoplastic resin in the product of the obtained fiber-reinforced thermoplastic resin molded product is thermoplastic resin B + C + D
In this case, the content of the modified thermoplastic resin C is desirably 0.5 to 20% by volume. Here, when the content ratio of the modified thermoplastic resin C is less than 0.5% by volume, the adhesion (adhesion) between the reinforcing fiber and the thermoplastic resin is made.
Is not sufficient, and the strength is not improved. Further, the modified thermoplastic resin C in which a carboxylic acid derivative is copolymerized or graft-polymerized in the main chain or side chain has a relatively poor thermal stability, so that its content is 20% by volume.
Is not preferable.

Further, modified thermoplastic resin C and thermoplastic resin D
And the ratio of the modified thermoplastic resin C in the product of the fiber-reinforced thermoplastic resin molded product is in the preferred range described above,
In addition, the content of the reinforcing fibers in the product may be adjusted so as to be in a preferable range.

When the above thermoplastic resin is used as a powdery thermoplastic resin, the powder preferably has a particle size of 10 to 300 μm. When the particle size is smaller than 10 μm, the cohesive force is strong,
A stable fluid state cannot be obtained. If it is larger than 300 μm, it is difficult to impregnate between the monofilaments. If a powder having a particle size in this preferred range cannot be obtained, a powder crushed by a crusher may be used.

The thermoplastic resin used in the present invention may be used alone or in combination, and a blend resin or an alloy resin of the above resins may be used.

The thermoplastic resin includes a heat stabilizer, a lubricant,
Additives such as processing aids, plasticizers, antioxidants, ultraviolet absorbers, modifiers, and colorants may be included.

Next, the thermoplastic resins A and C for the reinforcing fibers
Will be described.

As a method for obtaining a thermoplastic resin-impregnated reinforcing fiber in which the thermoplastic resin A or D is impregnated between the monofilaments of the reinforcing fiber, the following method is available.

After unwinding the monofilament bundle and aligning it in a unidirectional plane, a film made of thermoplastic resin A or D is stacked and passed between heated pinch rolls, and the molten thermoplastic resin is placed between the filaments of the reinforcing fibers. How to impregnate.

A method in which a molten thermoplastic resin is supplied while the monofilament bundle is passed through a crosshead type mold, and the molten thermoplastic resin is impregnated between the filaments of the reinforcing fibers by the supply pressure. When using this method, an extruder may be used for melting and supplying the thermoplastic resin.

As in the above two examples, when the method of impregnating the molten thermoplastic resin between the monofilaments by the external pressure is used, the viscosity range of the thermoplastic resin that can be used is limited, and JIS-K7210 “Thermoplastic plastic” is used. MFR (melt flow rate) measured by the "flow test method" must be about 30 or more. When a thermoplastic resin having a high viscosity, that is, an MFR of less than about 30 is used, the thermoplastic resin in a molten state cannot be impregnated between the monofilaments, and the breakage of the reinforcing fibers becomes significant. At this time, it is preferable to use a powdery thermoplastic resin, and it is possible to impregnate the thermoplastic resin between the monofilaments without breaking the reinforcing fibers.

Usually, a thermoplastic resin having an MFR of about 5 or less is used for extrusion molding. Therefore, the use of a powdery thermoplastic resin in the present invention is very useful.

As a method for obtaining a thermoplastic resin-impregnated reinforced fiber in which the thermoplastic resin A or D is impregnated between the monofilaments of the reinforcing fiber by using the powdery thermoplastic resin, a method in which the monofilament bundle is formed by powdery thermoplastic resin is used. The resin may be drawn into a tank in which the resin is kept in a fluidized state, and the powdered thermoplastic resin may be attached while breaking the monofilament bundle.

In this case, as a method of flowing the powdery thermoplastic resin, there are a method of vibrating the tank itself, a method of supplying a compressed gas into the tank, and the like.

As another example of a method for obtaining a reinforced fiber impregnated with a thermoplastic resin, a thermoplastic resin is finely dispersed in a solvent or the like in a tank, and is then placed in an emulsion state, that is, an emulsion state. The impregnation method can be used. This method is used for all thermoplastic resins because the combination of the thermoplastic resin and the solvent that can be made into an emulsion state is limited, and the solvent must be removed after impregnation and then supplied to the extruder. This is not a possible method.

As described above, the modified thermoplastic resin has good adhesiveness to the reinforcing fiber, and the obtained fiber-reinforced thermoplastic resin molded article has a high strength. In the present invention, it is preferable to use as a thermoplastic resin impregnated between the monofilaments of the reinforcing fibers, or to blend with a thermoplastic resin impregnated between the monofilaments. Therefore, if a small amount of the modified thermoplastic resin is used, the effect is small unless it is impregnated between the monofilaments instead of being blended with the thermoplastic resin B.

Next, the supply of the reinforcing fibers impregnated with the thermoplastic resin into the extruder while being kneaded and melted in the thermoplastic resin B will be described.

As a method for kneading and melting the thermoplastic resin B, a single-screw or twin-screw extruder, a kneader or the like can be used.

As a method of supplying the reinforcing fibers impregnated with the thermoplastic resin A or D into an extruder in which the thermoplastic resin B is kneaded and melted, an extruder in which the thermoplastic resin B is kneaded and melted is used. From the middle of the process, a method of supplying a thermoplastic resin impregnated reinforcing fiber, a method of supplying a thermoplastic resin impregnated reinforcing fiber while supplying a separately kneaded and melted thermoplastic resin B to an extruder, and the like. When the former method is used, it is necessary to increase the volume between the screw and the barrel so that the reinforcing fibers impregnated with the thermoplastic resin can be supplied. That is, the supply volume of the thermoplastic resin B so that the molten thermoplastic resin once compressed and heated by the screw in the extruder does not go out of the extruder through the supply port of the thermoplastic resin-impregnated reinforcing fiber provided in the extruder. In addition to the above, it is necessary to provide a large volume at least for the supply volume of the thermoplastic resin-impregnated reinforcing fibers. For the same reason, it is very difficult to feed the screw in the middle of the so-called compression section.

The supply form of the reinforcing fibers impregnated with the thermoplastic resin is as follows.
After being impregnated with the thermoplastic resin A or D, it may be cut into a desired length, but it is preferably supplied in a continuous fiber state in consideration of the remaining fiber length.

When the thermoplastic resin-impregnated reinforcing fiber is cut into a desired length and supplied, the reinforcing fiber preferably has an aspect ratio (reinforcing fiber length / monofilament diameter) of 100 or more, more preferably 300 or more. More preferably, there is. When the aspect ratio is 100 or less, the effect of the present invention for increasing the fiber length is small, and the length of the remaining fiber is short, so that the obtained fiber-reinforced thermoplastic resin molded article is weak.

When the reinforcing fibers impregnated with the thermoplastic resin are supplied, the thermoplastic resin impregnated between the monofilaments may be in a cooled state or a molten state. When a powdery thermoplastic resin is used, the powdery thermoplastic resin may be supplied only in a state of being impregnated with the powdery thermoplastic resin, or once heated to melt the powdery thermoplastic resin,
May be supplied.

However, it is preferable that the reinforcing fibers impregnated with the thermoplastic resin be supplied to the extruder in a state where the thermoplastic resin A or D is melted. That is, when the thermoplastic resin A or D is melted and impregnated between the monofilaments of continuous fibers, or after the reinforcing fiber is impregnated with the powdery thermoplastic resin, the thermoplastic resin A or D is heated and heated. When the thermoplastic resin impregnated in the reinforcing fiber is cooled and solidified, the handling of the thermoplastic resin-impregnated reinforcing fiber becomes complicated, and it becomes difficult to supply the extruder in a continuous fiber state. Therefore, it is better to supply the molten thermoplastic resin A or D to the extruder. As a method of supplying the thermoplastic resin A or D to the extruder in a molten state, a step of impregnating the reinforcing fiber with the thermoplastic resin A or D is provided near the supply port of the extruder, and the molten heat is supplied. A method of supplying the thermoplastic resin A or D to the extruder before the resin is cooled and solidified, or a process of impregnating the reinforcing fiber with the thermoplastic resin A or D from the step of passing the thermoplastic resin impregnated reinforcing fiber to the supply port of the extruder. A method in which the resin is heated to a temperature higher than the melting temperature of the resin is used.

When the reinforcing fibers impregnated with the powdery thermoplastic resin are supplied, or when the amount of the impregnated thermoplastic resin A or D is small, it is not necessary to use the above method. A guide or the like may be provided between the step of impregnating the reinforcing fibers with the plastic resin A or D and the supply port of the extruder to guide the thermoplastic resin-impregnated reinforcing fibers.

When the thermoplastic resin-impregnated reinforcing fibers are cut to a required length and supplied, a hopper may be provided at the supply port of the extruder, and the cut thermoplastic resin-impregnated reinforcing fibers may be supplied to the hopper. When the reinforcing fibers impregnated with the powdery thermoplastic resin are cut, the reinforcing fibers may be unraveled and bridged, and the supply may be delayed.

The reinforcing fibers in the fiber-reinforced thermoplastic resin molding are contained in an amount of 1 to 80% by volume,
A range of 50% by volume is particularly preferred. When the content is less than 1% by volume, the reinforcing effect is small. When the content is more than 80% by volume, the thermoplastic resin binding between the reinforcing materials is small, and the extrusion molding becomes very difficult.

The reinforcing fibers in the thermoplastic resin-containing reinforcing fibers are preferably impregnated so as to be in a range of 80% by volume or less. When the amount of the reinforcing fibers is more than 80% by volume, the amount of the thermoplastic resin A or D existing between the monofilaments is small, and even after mixing with the thermoplastic resin B, the surface area where the monofilaments and the thermoplastic resin are in contact increases. Without this, the strength of the obtained fiber-reinforced thermoplastic resin molded article becomes weak.

Next, the mixing of the thermoplastic resin impregnated fibers into the thermoplastic resin B will be described.

The mixing of the thermoplastic resin B and the reinforcing fibers impregnated with the thermoplastic resin may be performed by using a single-screw or twin-screw extruder or kneader as in the case of kneading and melting the thermoplastic resin B. For fiberization, a single screw extruder having a screw with a volume compression ratio of 2.0 or less may be used.

Here, the volume compression ratio means a volume constituted by a screw diameter of a portion where a thermoplastic resin impregnated reinforcing fiber is supplied and a diameter of an extruder cylinder (barrel), and a screw diameter and an extrusion diameter at a downstream side of the screw. Machine cylinder (barrel)
It is a value that is reduced by the volume of the portion where the volume composed of the diameter and the smallest. In the case of performing both the melt mixing of the thermoplastic resin B and the mixing of the thermoplastic resin-impregnated reinforcing fibers with a single screw, a so-called compression unit, which may be a screw provided with a plurality of measurement units, In the present invention, the volume compression ratio refers to a volume compression ratio of a portion where the thermoplastic resin B and the thermoplastic resin-impregnated reinforcing fiber are mixed.

The cutting of the reinforcing fibers in the screw of the extruder is performed by compressing the supplied thermoplastic resin and most rapidly applying shear to the thermoplastic resin. By supplying the thermoplastic resin-impregnated reinforcing fibers to B, the volume compression ratio of the compression section can be reduced, and the remaining fiber length can be increased.

If the dispersion of the reinforcing fibers in the thermoplastic resin B is not good, a portion for assisting kneading may be provided at the tip of the screw as long as the reinforcing fibers are not cut.

On the other hand, twin-screw extruders and kneaders are usually excellent in the self-cleaning ability of the screw, and the position of the molten thermoplastic resin in the screw is frequently exchanged. In addition, it is necessary to adjust the melt compression ratio and the gap for screw engagement.

In the present invention, fillers such as talc, mica, calcium carbonate, wood powder, synthetic resin pulverized powder, and fiber-reinforced synthetic resin pulverized powder are blended within a range not to hinder the reinforcement of the thermoplastic resin by the reinforcing fibers. Is also good.

Next, the extrusion mold will be described.

The extrusion mold used in the present invention may be an extrusion mold used in ordinary extrusion molding. However, the cross-sectional shape of the flow passage becomes extremely small or deformed, and the flow of the thermoplastic resin into the thermoplastic resin is reduced. Care must be taken not to apply shear forces due to sudden changes.

[0064]

Next, an embodiment of the present invention will be described.
This will be described with reference to the drawings.

Referring first to FIG. 1, claim 1 of the present invention
And a thermoplastic resin containing a thermoplastic resin impregnated reinforcing fiber R in which the thermoplastic resin A is impregnated between monofilaments of the reinforcing fiber, or a modified thermoplastic resin C bonded with a carboxylic acid derivative. Resin D
The resin impregnating device for producing the thermoplastic resin impregnated reinforcing fiber S, which is impregnated between the monofilaments of the reinforcing fiber, comprises a twin screw extruder (11), a preheating device (12),
(13) and a take-off machine (14). Preheating device (12)
Is an apparatus for heating with an infrared heater or the like while passing reinforcing fibers such as glass roving, impregnation mold (13),
This is a mold for impregnating molten thermoplastic resin between monofilaments of the reinforcing fibers while extracting the reinforcing fibers along the resin flow path.

The thermoplastic resin A or D melted by the twin-screw extruder (11) and the reinforcing fiber heated by the preheating device (12) are introduced into the heating impregnation mold (13), and the thermoplastic resin impregnation is performed. The thermoplastic resin A or D is impregnated so that the ratio of the reinforcing fibers in the reinforcing fibers R becomes a predetermined ratio.

Next, referring to FIG. 2, the apparatus for producing a fiber-reinforced thermoplastic resin molded body comprises a single-screw extruder (21) and a plate-shaped body extrusion die (22). Here, single screw extruder (21)
Has a screw composed of a first resin supply section, a first compression section, a second resin supply section, a second compression section, and a measurement section. The volume compression ratios of the first compression section and the second compression section are the same, and the screw groove depths of the first supply section and the second supply section are the same. A reinforcing fiber supply port (23) is provided in the middle of the barrel of the single screw extruder (21).
According to (23), the reinforcing fiber is supplied to the second supply portion of the screw.

Then, the thermoplastic resin B is fed into a single screw extruder (21).
After kneading and melting up to the first compression section, the reinforcing fiber supply port (2
From 3), the thermoplastic resin impregnated reinforcing fibers R or S prepared by the resin impregnating apparatus of FIG. 1 are supplied. In this case, the apparatus shown in FIG. 1 is preferably installed near the apparatus shown in FIG. 2, and is supplied to the single screw extruder (21) before the thermoplastic resin A or D impregnated in the reinforcing fibers is cooled and solidified.

After supplying the thermoplastic resin impregnated reinforcing fibers R or S to the single screw extruder (21), the molten thermoplastic resin B and the thermoplastic resin impregnated reinforcing fibers R or S are mixed in the second compression section.
After mixing in the measuring section, the mixture is supplied to a plate-shaped body extrusion die (22), and a fiber-reinforced thermoplastic resin molded body composed of a plate-shaped body is obtained from the extrusion die (22) by extrusion molding.

Referring to FIG. 3, according to the third aspect of the present invention, there is provided a powdery thermoplastic resin A containing a powdery thermoplastic resin A or a modified thermoplastic resin C having a carboxylic acid derivative bound between monofilaments. The resin impregnating device for producing the thermoplastic resin-impregnated reinforced fibers U impregnated with the thermoplastic resin D includes a powder resin tank (31) and a heating device (32). The bottom of the powder resin tank (31) is made of non-woven fabric,
By supplying compressed air from the back side of the bottom surface, the powdery thermoplastic resin A or D is in a flowing state. As the heating device (32), the same preheating device as in the case of FIG. 1 may be used.

Then, the reinforcing fibers were drawn into a powder resin tank (31) in which the powder thermoplastic resin was flowing, and the thermoplastic resin was impregnated between the monofilaments while being broken into monofilaments. Next, the powdered thermoplastic resin impregnated reinforced fiber U drawn out from the powdered resin tank (31) is heated by passing it through a heating device (32) to melt the thermoplastic resin, thereby producing a thermoplastic resin impregnated reinforced fiber U. I do. At this time, the powder resin tank (3
The impregnation is performed such that the ratio of the reinforcing fibers in the thermoplastic resin-impregnated reinforcing fibers U to the thermoplastic resin is adjusted by adjusting the passing speed in 1).

(Function) In the above, the first aspect of the present invention is described.
According to the described invention, the thermoplastic resin A is impregnated between the monofilaments of the reinforcing fibers in advance, and then mixed with the thermoplastic resin B serving as a matrix. Since it is not necessary to perform impregnation, the cutting of the reinforcing fibers is small.

Since the composite with the thermoplastic resin is reliably performed in monofilament units, the contact surface area between the monofilament surface and the thermoplastic resin is large.

For the above reasons, the obtained fiber-reinforced thermoplastic resin molded article has high strength.

According to the invention of claim 2 of the present invention, the thermoplastic resin impregnated into the thermoplastic resin impregnated fibers has:
Uses a modified thermoplastic resin to which a carboxylic acid derivative is bonded, and allows a modified thermoplastic resin with excellent adhesion to reinforcing fibers to be reliably located at the interface between the reinforcing fibers and the thermoplastic resin. It is most effective also in compounding reinforcing fibers.

For the above reasons, the obtained fiber-reinforced thermoplastic resin molded article has high strength.

In any of the above methods, since the thermoplastic resin-impregnated reinforcing fibers are supplied to the thermoplastic resin B in a molten state in advance, the volume compression required for melt kneading with a normal single screw is sufficient. And a single-screw extruder having a screw with a volume compression ratio of 2.0 or less can be used as a melt extruder. The length can be made longer and the cutting of reinforcing fibers is less.

For the above reasons, the obtained fiber-reinforced thermoplastic resin molded article has higher strength.

Further, according to the third aspect of the present invention, when impregnating between the monofilaments, the monofilament is impregnated with the powdery thermoplastic resin by passing the monofilament through a tank kept in a fluidized state. Since it is possible to impregnate a high-viscosity thermoplastic resin suitable for extrusion molding without high resin pressure, there is little cutting of reinforcing fibers.

In this case, first, the powdery thermoplastic resin is positioned between the monofilaments in a solidified state in the first stage, and then the thermoplastic resin is melted and impregnated between the monofilaments in the second stage. Compared with the impregnation only by the flow of the resin, since the composite with the thermoplastic resin is performed more reliably in the unit of the monofilament, the contact surface area between the surface of the monofilament and the thermoplastic resin is larger.

For the above reasons, the obtained fiber-reinforced thermoplastic resin molded article has higher strength.

Also in this method, since the reinforcing fibers impregnated with the powdery thermoplastic resin in advance between the monofilaments are supplied to the extruder, it is not necessary to abruptly compress the volume in the extruder, and the above steps are performed. At this time, a single screw extruder having a screw having a volume compression ratio of 2.0 or less can be used as a melt extruder of the thermoplastic resin-impregnated reinforcing fiber and the thermoplastic resin, so that the remaining fiber length can be increased. And higher strength can be obtained.

[0083]

Next, an embodiment of the present invention will be described with reference to the drawings.

In the following examples, a long plate having a width of 150 mm and a thickness of 3 mm was manufactured according to the manufacturing method of the present invention.

Example 1 A glass continuous fiber (glass roving, 670 TEX) having a diameter of 13 μm was used as a reinforcing fiber, and a high density polyethylene (JIS-K7210) was used as a thermoplastic resin A.
The melt flow rate measured at 70) was used.

Using the apparatus shown in FIG. 1, a reinforcing fiber R impregnated with a thermoplastic resin was prepared. The apparatus comprises a twin-screw extruder (11) having a barrel diameter of 30 mm, a preheating device (12), an impregnating mold (13), and a take-off machine (14). The preheating device (12) is a device that heats with an infrared heater while passing through the glass roving, and the impregnation mold (13) melts the glass roving between the monofilaments while extracting the glass roving along the resin flow path. This is a mold for impregnating the obtained thermoplastic resin.

A high-density polyethylene melted by a twin-screw extruder (11) having a barrel diameter of 30 mm, and three glass rovings heated to 250 ° C. by a preheating device (12) were impregnated into a 200 ° C. impregnation mold ( 13), and impregnated with high-density polyethylene so that the ratio of the reinforcing fibers in the thermoplastic resin-impregnated reinforcing fibers was 75% by volume.

Next, a fiber-reinforced thermoplastic resin molded body was manufactured using the apparatus shown in FIG. The device has a diameter of 50
A single-screw extruder (21) and a plate-shaped body extrusion die (22).
The single screw extruder having a diameter of 50 mm has a screw including a first resin supply unit, a first compression unit, a second resin supply unit, a second compression unit, and a measurement unit. The volume compression ratios of the first compression section and the second compression section are both 3.0, and the screw groove depths of the first supply section and the second supply section are the same. A reinforcing fiber supply port (23) is provided in the middle of the barrel of the single screw extruder, and the reinforcing fiber supply port (23) has a structure capable of supplying the reinforcing fiber to the second supply section of the screw. .

The thermoplastic resin B is a modified thermoplastic resin in which a carboxylic acid derivative is bonded to high-density polyethylene having a melt flow rate of 0.5 (trade name: Admer HB)
500, manufactured by Mitsui Petrochemical Industry Co., Ltd.) in a tumbler so as to be 10% by volume.

After the thermoplastic resin B was kneaded and melted up to the first compression section of an extruder having a barrel diameter of 50 mm,
From the reinforcing fiber supply port, three thermoplastic resin-impregnated reinforcing fibers prepared under the above conditions were supplied. The apparatus shown in FIG. 1 was installed near the apparatus shown in FIG. 2, and was supplied to a single-screw extruder (21) having a barrel diameter of 50 mm before the high-density polyethylene impregnated in the reinforcing fibers was cooled and solidified.

After supplying the thermoplastic resin-impregnated reinforcing fibers to the single-screw extruder (21) having a diameter of 50 mm, the molten high-density polyethylene (thermoplastic resin B) and the thermoplastic resin-impregnated reinforcing fibers are measured in the second compression section. After mixing in the part, the plate-shaped body extrusion die
(22).

A plate sample was extruded from a plate extrusion mold (22) whose temperature was adjusted to 200 ° C.

The reinforcing fiber content of the plate-like body thus obtained was 20% by volume.

Example 2 The conditions were the same as in Example 1, except that only high-density polyethylene having a melt flow rate of 0.5 was used as the thermoplastic resin B under the same conditions.

Extrusion molding was performed under the same conditions as in Example 1.

The fiber reinforced thermoplastic resin plate thus obtained had a reinforcing fiber content of 20% by volume.

Example 3 The same glass roving as in Example 1 was used as the reinforcing fiber, and a modified thermoplastic resin having a carboxylic acid derivative bonded thereto as a modified thermoplastic resin C (trade name: Admer HB50)
0, manufactured by Mitsui Petrochemical Industry Co., Ltd.)
As high-density polyethylene (melt flow rate is 7
A mixture obtained by mixing the modified thermoplastic resin C with a tumbler so that the volume of the modified thermoplastic resin C became 50% by volume was used.

Using the apparatus shown in FIG. 1 in the same manner as in Example 1, thermoplastic resin-impregnated reinforced fibers S were prepared.

A high-density polyethylene containing a modified thermoplastic resin melted and mixed by a twin-screw extruder (11) having a barrel diameter of 30 mm and three glass rovings heated to 250 ° C. by a pre-heating device (12) are heated to 200 ° C. Introduced into the heated impregnation mold (13), and the ratio of the reinforcing fibers in the thermoplastic resin impregnated reinforcing fibers was 6%.
The modified thermoplastic resin-containing high-density polyethylene was impregnated so as to be 0% by volume.

Extrusion was performed under the same conditions as in Example 1.

The fiber-reinforced thermoplastic resin plate thus obtained had a reinforcing fiber content of 20% by volume.

Example 4 The conditions were the same as in Example 3. Under the conditions, the same apparatus as in Example 1 was used, but only the screw was different. That is, the volume compression ratio of the first compression section of the screw is 3.0, and the volume compression ratio of the second compression section is 1.5. Also the first
The screw groove depths of the supply section and the second supply section were the same.

Extrusion molding was performed under the same conditions as in Example 1.

The fiber reinforced thermoplastic resin plate thus obtained had a reinforcing fiber content of 20% by volume.

Example 5 The same glass roving as that of Example 1 was used as the reinforcing fiber, and a modified thermoplastic resin to which a carboxylic acid derivative was bonded as the modified thermoplastic resin C (trade name: Admer HB50)
0, manufactured by Mitsui Petrochemical Industry Co., Ltd.)
As high-density polyethylene (melt flow rate is 7
0) and the modified thermoplastic resin C were blended in a ratio of 50% by volume: 50% by volume, and pulverized by a freezing pulverizer to obtain a powdery thermoplastic resin having an average particle diameter of 100 μm. Using.

Using the apparatus shown in FIG. 3, a reinforcing fiber U impregnated with a thermoplastic resin was prepared. The apparatus comprises a powder resin tank (31) and a heating device (32). The bottom surface of the powder resin tank (31) is made of a nonwoven fabric, and by supplying compressed air from the back side of the bottom surface, the powdery thermoplastic resin is in a fluidized state. As the heating device (32), the preheating device shown in FIG. 1 of Example 1 was used.

[0107] Three glass rovings were drawn into the powder resin tank (31) in which the powdered high-density polyethylene was flowing, and were melted into a monofilament while being impregnated between the monofilaments. Then the powder resin tank (3
The powdered high-density polyethylene impregnated glass roving drawn out from 1) was heated to 200 ° C. by passing through a heating device to melt the high-density polyethylene, thereby producing a thermoplastic resin-impregnated reinforced fiber U. At this time, powder resin tank (31)
The high-density polyethylene was impregnated so that the ratio of the reinforcing fibers in the thermoplastic resin-impregnated reinforcing fibers was 60% by volume by adjusting the speed at which the fibers were passed through.

Extrusion molding was performed under the same conditions as in Example 1 except for the above conditions.

The fiber reinforced thermoplastic resin plate thus obtained had a reinforcing fiber content of 20% by volume.

Example 6 Extrusion was carried out under the same conditions as in Example 5, under the same conditions as in Example 4, and under the same conditions as in Example 1.

The fiber-reinforced thermoplastic resin plate thus obtained had a reinforcing fiber content of 20% by volume.

Example 7 The same glass roving as in Example 1 was used as the reinforcing fiber.

As the thermoplastic resin A, the modified thermoplastic resin C used in Example 3 was blended with high-density polyethylene (melt flow rate 1.0) and pulverized by a freezing-pulverizer to obtain an average particle diameter of 100 μm. Was used as the powdery thermoplastic resin.

The production of the reinforcing fibers U impregnated with the thermoplastic resin was the same as in Example 4, and the high-density polyethylene was impregnated so that the ratio of the reinforcing fibers was 60% by volume.

Extrusion molding was performed under the same conditions as in Example 1.

The fiber-reinforced thermoplastic resin plate thus obtained had a reinforcing fiber content of 20% by volume.

Example 8 Extrusion molding was carried out under the same conditions as in Example 7, under the same conditions as in Example 4, and under the same conditions as in Example 1.

The fiber-reinforced thermoplastic resin plate thus obtained had a reinforcing fiber content of 20% by volume.

Example 9 The same glass roving as in Example 1 was used as the reinforcing fiber. A modified thermoplastic resin to which a carboxylic acid derivative is bonded as the modified thermoplastic resin C (trade name: Admer HB500,
Using Mitsui Petrochemical Industries, Ltd.) as the thermoplastic resin D, high-density polyethylene (having a melt flow rate of 1.
A mixture obtained by mixing the modified thermoplastic resin C with a tumbler so that the volume of the modified thermoplastic resin C became 50% by volume was used.

Using the same apparatus as in Example 1, high-density polyethylene containing a modified thermoplastic resin was impregnated between monofilaments so that the ratio of the reinforcing fibers was 60% by volume. For this reason, there were portions that were not impregnated between the monofilaments. Further, the glass roving was partially cut by the resin pressure.

Extrusion was performed under the same conditions as in Example 5.

The reinforcing fiber content of the fiber reinforced thermoplastic resin plate thus obtained was 20% by volume.

Example 10 Extrusion molding was carried out under the same conditions as in Example 9, under the same conditions as in Example 4, and under the same conditions as in Example 1.

The fiber-reinforced thermoplastic resin plate thus obtained had a reinforcing fiber content of 20% by volume.

Comparative Example 1 For comparison, a long plate was produced as follows.

The same reinforcing fibers as in Example 1 were used. As the thermoplastic resin, a melt flow rate of 0.5
And a high-density polyethylene having a melt flow rate of 70 were mixed with a tumbler so that the mixing ratio was 5: 1.

A fiber-reinforced thermoplastic resin molded body was manufactured using the apparatus used in Example 1, that is, the apparatus having a volume compression ratio of the second compression section of 3.0.

The mixed thermoplastic resin and glass roving were supplied from a first resin supply section of a single screw extruder having a diameter of 50 mm.

After kneading and melting the thermoplastic resin mixture and the glass roving in a single screw extruder having a diameter of 50 mm,
It was supplied to a plate-shaped extrusion die.

[0130] A plate sample was extruded from a plate extrusion die adjusted to a temperature of 200 ° C.

The reinforcing fiber content of the plate-like body thus obtained was 20% by volume.

Comparative Example 2 As the thermoplastic resin under the conditions, high density polyethylene having a melt flow rate of 0.5 and melt flow rate of 7 were used.
0 and a modified thermoplastic resin (trade name: ADMER HB500, manufactured by Mitsui Petrochemical Industry Co., Ltd.) to which a carboxylic acid derivative is bonded at a mixing ratio of 10:
What was mixed with a tumbler so that it became 1: 1 was used.

Extrusion molding was performed under the same conditions as in Comparative Example 1.

The fiber-reinforced thermoplastic resin plate thus obtained had a reinforcing fiber content of 20% by volume.

Comparative Example 3 The conditions were the same as in Comparative Example 2, and the conditions were substantially the same as those in Example 1, that is, the apparatus shown in FIG. 2 was used to produce a fiber-reinforced thermoplastic resin molded article. However, the extruder is 2
Using a shaft kneading extruder, the mixed thermoplastic resin and glass roving were supplied from the supply section of the screw.

The thermoplastic resin mixture and the glass roving were kneaded and melted in a twin-screw kneading extruder, and then supplied to a plate-shaped extrusion die.

Extrusion molding was performed under the same conditions as in Example 1.

The fiber-reinforced thermoplastic resin plate thus obtained had a reinforcing fiber content of 20% by volume.

Comparative Example 4 The conditions were the same as those in Comparative Example 2, and the conditions were the same as those used in Example 3, that is, the apparatus having the volume compression ratio of the second compression section of 1.5 was used to mold the fiber-reinforced thermoplastic resin. Body manufactured.
Thermoplastic resin mixture and glass roving 50mm diameter
From the first resin supply section of the single screw extruder.

Extrusion molding was performed under the same conditions as in Comparative Example 1.

The reinforcing fiber content of the fiber reinforced thermoplastic resin plate thus obtained was 20% by volume.

<Evaluation of Dispersion State> Each of the plate-like molded articles obtained in Examples 1 to 10 and Comparative Examples 1 to 4 was stretched to a thickness of 0.5 mm by a hot press at 220 ° C. The degree of impregnation of the plastic resin was evaluated.

<Evaluation of Residual Fiber Length> Each plate obtained in the above Examples and Comparative Examples was heated in a furnace at 500 ° C. to completely incinerate the thermoplastic resin component, thereby obtaining fired glass fibers. Was. The glass fiber was observed under magnification from a microscope through a CCD camera on a monitor, and the fiber length was measured from the dimensions on the monitor and the magnification. 500 measurements were performed for each plate, and the number average value was taken as the residual fiber length.

<Evaluation of Tensile Strength> Tensile test pieces were cut out from each plate obtained in the above Examples and Comparative Examples, and AS
According to TM-D638, the tensile strength was measured for the extrusion method (MD).

Table 1 shows the results of each evaluation.

[0146]

[Table 1] As is clear from the results of the above table, Examples 1 to 5 of the present invention
The fiber-reinforced thermoplastic resin molded article obtained in 10 has a good dispersion state of the reinforcing fibers, but in Comparative Examples 2 and 4, the impregnation defective portion, that is, the glass roving was not unraveled, and the white portion in a streak shape was not observed. Was observed. Further, the fiber-reinforced thermoplastic resin molded products obtained in Examples 1 to 10 of the present invention,
In each case, the residual fiber length is long, and therefore, both have high tensile strength.

On the other hand, the molded article obtained in Comparative Example 1 had a short fiber length and a low tensile strength. The molded articles obtained in Comparative Examples 2 to 4 also have a shorter fiber length and a smaller tensile strength than the molded articles of Examples in which the ratio of the modified thermoplastic resin in the molded article is almost the same. there were.

[0148]

According to the invention of the method for producing a fiber-reinforced thermoplastic resin molded article according to the first aspect of the present invention, as described above, the thermoplastic resin A is impregnated between the monofilaments of the reinforcing fiber. The impregnated reinforcing fibers R are supplied into an extruder in which the same or different thermoplastic resins B are kneaded and melted, the thermoplastic resin impregnated reinforcing fibers R are mixed into the thermoplastic resins B, and then the extrusion die is By passing through, a step of obtaining a fiber-reinforced thermoplastic resin molded article is included, so that the adhesion between the reinforcing fiber and the thermoplastic resin is good, and the remaining fiber length remains long, so that the obtained fiber-reinforced thermoplastic resin molding is obtained. The body becomes stronger.

Next, the invention of the method for producing a fiber-reinforced thermoplastic resin molded article according to claim 2 of the present invention is characterized in that the thermoplastic resin D containing the modified thermoplastic resin C to which the carboxylic acid derivative is bonded is made of reinforced fiber. The thermoplastic resin impregnated reinforcing fiber S impregnated between the monofilaments is supplied into an extruder in a state where the thermoplastic resin B is kneaded and melted, and the thermoplastic resin impregnated reinforcing fiber S is mixed into the thermoplastic resin B. Then, after that, by passing through the extrusion die, including the step of obtaining a fiber-reinforced thermoplastic resin molded body, a modified thermoplastic resin having good adhesion to the thermoplastic resin in contact with the reinforcing fibers is ensured. Since it is contained, higher strength can be obtained.

In any of the above methods, the reinforcing fibers impregnated with the thermoplastic resin A or D between the monofilaments are supplied to the extruder. Therefore, it is not necessary to rapidly compress the volume in the extruder. When performing, a single screw extruder having a screw having a volume compression ratio of 2.0 or less can be used as a melt extruder of the thermoplastic resin-impregnated reinforcing fiber and the thermoplastic resin, so that the remaining fiber length is longer. It can be fiberized and higher strength can be obtained.

Further, according to the invention of the method for producing a fiber-reinforced thermoplastic resin molded product according to the third aspect of the present invention, a continuous process is carried out in a tank in which the powdery thermoplastic resin A or D is contained in a fluidized state. The monofilament bundle is introduced, the thermoplastic resin impregnated reinforcing fiber U formed by impregnating the powdery thermoplastic resin A or D between the monofilaments while the monofilament bundle is unraveled in the tank, and the thermoplastic resin B is kneaded and melted. In the extruder in the extruded state, mixing the thermoplastic resin-impregnated reinforcing fibers U in the thermoplastic resin B, and then passing through an extrusion die to obtain a fiber-reinforced thermoplastic resin molded body. Since it contains, it is possible to impregnate high-viscosity thermoplastic resin that is suitable for extrusion molding and difficult to impregnate with molten resin, and it is possible to mold high-strength fiber-reinforced thermoplastic resin. Not only is obtained, in which range of the manufacturing method of the present invention is increased.

Also in this method, since the reinforcing fibers impregnated with the powdery thermoplastic resin in advance between the monofilaments are supplied to the extruder, it is not necessary to abruptly compress the volume in the extruder, and the above steps are performed. At this time, a single screw extruder having a screw having a volume compression ratio of 2.0 or less can be used as a melt extruder of the thermoplastic resin-impregnated reinforcing fiber and the thermoplastic resin, so that the remaining fiber length can be increased. This has the effect that higher strength can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view of an apparatus for impregnating a reinforcing fiber with a resin used in an embodiment of the present invention.

FIG. 2 is a schematic vertical sectional view of an apparatus for producing a fiber-reinforced thermoplastic resin molded article used in an example of the present invention.

FIG. 3 is a schematic longitudinal sectional view of an apparatus for impregnating a reinforcing fiber with a resin used in an embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 11 twin screw extruder 12 preheating device 13 impregnation die 14 take-off device 21 single screw extruder 22 extrusion die 23 reinforcing fiber supply port 31 powder resin tank 32 heating device

Claims (4)

[Claims] 1. A thermoplastic resin-impregnated reinforcing fiber R obtained by impregnating a thermoplastic resin A between monofilaments of a reinforcing fiber.
Is supplied to an extruder in a state where the thermoplastic resin B is kneaded and melted, the thermoplastic resin-impregnated reinforcing fibers R are mixed into the thermoplastic resin B, and then passed through an extrusion die, thereby forming a molded product. A method for producing a fiber-reinforced thermoplastic resin molded article, comprising the step of: 2. A thermoplastic resin-impregnated reinforcing fiber S obtained by impregnating a thermoplastic resin D containing a modified thermoplastic resin C with a carboxylic acid derivative bound between monofilaments of a reinforcing fiber, and a thermoplastic resin B being kneaded. The method includes a step of supplying a molten state into an extruder, mixing a thermoplastic resin-impregnated reinforcing fiber S in a thermoplastic resin B, and then passing the mixture through an extrusion die to obtain a molded body. A method for producing a fiber-reinforced thermoplastic resin molded article. 3. A powdery thermoplastic resin A or a powdery thermoplastic resin D containing a modified thermoplastic resin C to which a carboxylic acid derivative is bonded is continuously placed in a tank in a fluidized state. A monofilament bundle is introduced, and a thermoplastic resin-impregnated reinforced fiber U obtained by impregnating a powdery thermoplastic resin A or D between monofilaments in a tank is mixed with an extruder in which a thermoplastic resin B is kneaded and melted. And mixing the thermoplastic resin-impregnated reinforced fibers U in the thermoplastic resin B, and then passing the mixture through an extrusion mold to obtain a molded article, wherein the fiber-reinforced thermoplastic resin A method for producing a molded article. 4. The fiber-reinforced thermoplastic resin molded article according to claim 1, wherein the extruder is a single screw extruder provided with a screw having a volume compression ratio of 2.0 or less. Manufacturing method.