JPH10235641A - Resin pellet, its manufacture and molding composition using the resin pellet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize pellets, which are hard to crack and have favorable shape and out of which a molded article of natural color is obtained. SOLUTION: By passing an opened continuous fiber bundle A through a soaking tank 2, a thermoplastic resin emulsion is uniformly and surely adheres to respective monofilaments and then introduced in a heating drier 4 in order to dry and melt the thermoplastic resin emulsion. The resin coated continuos fiber bundle B is axially twisted with a twister 5 so as to prevent the coated thermoplastic resin from separating in order to cut the twisted continuos fiber bundle C after a cooler 12 with a pelletizer 14 into a predetermined length for obtaining pellets P. By mixing the pellets P with a matrix resin, a molding composition is prepared.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fiber-reinforced resin pellet made from a continuous fiber bundle obtained by coating with a thermoplastic resin emulsion, a method for producing the resin pellet, and the use of the resin pellet. The present invention relates to a molding composition.

[0002]

2. Description of the Related Art For example, a conventional method for producing glass fiber reinforced thermoplastic resin pellets is as follows. Method of dispersing in resin and pelletizing (2) Continuous fiber bundle of glass fiber, that is, glass fiber roving is passed through molten thermoplastic resin, and glass fiber is coated with resin by a so-called pultrusion method,
Then, a method of cutting and pelletizing (3) There is a method of dipping glass fiber roving in a thermoplastic resin emulsion, drying it, and then cutting and pelletizing.

[0003]

In these methods for producing glass fiber reinforced thermoplastic resin pellets, the method of dipping glass fiber rovings in a thermoplastic resin emulsion, drying the glass rovings, and then cutting and pelletizing the glass fiber rovings, Even if roving is immersed in a thermoplastic resin emulsion, it is difficult to attach a large amount of resin to the monofilament because the concentration of the emulsion is generally low.

[0004] Even if the resin can be adhered to the monofilament, it is difficult to use the resin for molding.
When the pellets are cut into small pieces, the pellets are easily broken to produce fine glass fibers.

[0005] Even if pellets are obtained, they have the feature of containing glass fibers in a high concentration due to the small amount of adhered resin. When mixed with matrix resin pellets and molded, the released glass fibers form fluff and become apparent in the molded product, or increase the dry melting temperature of the adhered resin to increase the shape retention of the pellet. There was a fatal problem such as a decrease in the hue of the molded product.

SUMMARY OF THE INVENTION In view of the above situation, the present invention provides uniform and reliable thermoplastic fibers in each of the monofilaments constituting the continuous fiber bundle by performing a fiber opening treatment when the continuous fiber bundle is immersed in the thermoplastic resin emulsion. By adopting a novel processing means of twisting the continuous fiber bundle coated with thermoplastic resin by applying a resin emulsion, it has a high fiber concentration, hardly breaks into pellets, and has good shape. It is an object of the present invention to provide a resin pellet capable of obtaining a molded product of a natural color, a production method capable of producing the resin pellet, and a molding composition using the resin pellet. .

[0007]

Means for Solving the Problems In order to achieve the above object, a resin fiber pellet according to the present invention is immersed in a thermoplastic resin emulsion, and then dried and melted to adhere to the thermoplastic resin to form a continuous fiber bundle. Is twisted, cut into a predetermined length, and pelletized.

In the method for producing resin pellets of the present invention, a continuous fiber bundle which has been spread is immersed in a thermoplastic resin emulsion, and the adhered thermoplastic resin is dried and melted to twist the continuous fiber bundle coated with the resin. Thereafter, the mixture is cooled, and then cut into a predetermined length to be pelletized.

Further, the molding composition of the present invention is immersed in a thermoplastic resin emulsion, and then the attached thermoplastic resin is dried and melted to twist a continuous fiber bundle coated with the resin. Characterized in that a thermoplastic resin is blended with resin pellets obtained by cutting into pieces.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS There are no particular restrictions on the type of fiber in the continuous fiber bundle used in the present invention.
High-melting fibers such as carbon fibers, metal fibers, and aromatic polyamide fibers can be used. Among these fibers, the strength and price of the obtained resin pellets and the molding composition using the same are taken into consideration. If so, the use of glass fibers is particularly preferred.

[0011] The fiber-reinforced thermoplastic resin pellets of the present invention are specifically prepared by the following steps: (1) Opening individual monofilaments constituting a continuous fiber bundle in parallel at intervals. Thereafter, the opened monofilament is immersed in a thermoplastic resin emulsion, and the thermoplastic resin is uniformly attached to the surface of each monofilament. (2) The continuous fiber bundle to which the thermoplastic resin is attached is heated. To evaporate the water and melt the adhered resin solids to ensure that the surface of the monofilament is covered with the thermoplastic resin. (3) Twisting and twisting the continuous fiber bundle coated with the thermoplastic resin (4) a step of cooling the twisted continuous fiber bundle; and (5) a step of cutting the cooled continuous fiber bundle into a predetermined length to form a resin pellet. Those obtained by a process according to bets, these steps can be accomplished continuously by more manufacturing apparatus specifically illustrated in FIG.

The manufacturing apparatus 1 includes a dipping tank 2 for uniformly adhering a thermoplastic resin to each of the monofilaments constituting the continuous fiber bundle A, and a thermoplastic resin obtained in the dipping tank 2 having a uniform surface. Heating and drying unit 4 for evaporating the moisture of the continuous fiber bundle A adhered to the resin and melting the resin solids, and twisting the continuous fiber bundle B coated with the thermoplastic resin obtained by the heat drying treatment. And a cooler 1 for cooling the continuous fiber bundle C twisted by the twisting machine 5
2 and a pelletizer 14 for cutting the continuous fiber bundle C after cooling into resin pellets P of a predetermined length.

The continuous fiber bundle A introduced into the immersion tank 2 is
Prior to immersion, the individual monofilaments are set in an open state. For this purpose, the continuous fiber bundle A is passed through the surface of the roller 3 while being tensioned, or the monofilaments of the continuous fiber bundle A are scattered by static electricity. For example, a means such as making

The emulsion of the thermoplastic resin contained in the immersion tank 2 is made of a thermoplastic resin of the same kind or a close relation to the matrix resin in consideration of the compatibility with the matrix resin constituting the resin composition for molding. It is desirable to use.

When the acrylonitrile / styrene copolymer (AS resin) is used as the matrix resin, acrylonitrile / styrene copolymer emulsion (AS emulsion), styrene / acrylic acid copolymer, styrene / methacrylate copolymer and styrene -An emulsion such as a methyl methacrylate copolymer can be used.

When the matrix resin is polystyrene, a styrene / butadiene copolymer emulsion (SB latex) is used. When the matrix resin is polyethylene, an emulsion of an ethylene / vinyl acetate copolymer or an ethylene / methacrylic acid copolymer is used. Can be used.

The preferable amount of the thermoplastic resin emulsion to be adhered in the immersion tank 2 is 5 to 100 parts by weight, more preferably 5 to 100 parts by weight, per 100 parts by weight of the continuous fiber bundle A, in terms of the amount of the adhered resin after drying the emulsion. Is 10 to 70 parts by weight. When the amount is less than 5 parts by weight, the individual monofilaments constituting the continuous fiber bundle A are not completely dispersed in the matrix resin, and even when the amount exceeds 100 parts by weight, a coating having a thickness corresponding to this is obtained. Not economically disadvantageous. The preferred resin solid content of the emulsion is 30 to
It is in the range of 70% by weight.

The method of immersing the continuous fiber bundle A in the thermoplastic resin emulsion can be achieved by simply placing the thermoplastic resin emulsion in the immersion tank 2 and passing the continuous fiber bundle A opened in the thermoplastic resin emulsion. Preferably, a vibrator such as an ultrasonic oscillator is installed in the immersion tank 2, and the thermoplastic resin emulsion is vibrated by the vibrator to improve the coating effect on the monofilament by immersion.

The preferred passing speed of the continuous fiber bundle A in the immersion tank 2 is 5 to 30 m / min. By passing the continuous fiber bundle A at such a speed, each monofilament of the opened continuous fiber bundle A is heated. The plastic resin emulsion can adhere to form a uniform coating.

The continuous fiber bundle A to which the thermoplastic resin emulsion is adhered by the immersion treatment in the immersion tank 2 is subjected to evaporation of the moisture of the thermoplastic resin emulsion adhered to the surface of the monofilament by a heating dryer 4 having a heater or the like. The coating is formed more reliably by melting the resin.

The heating / drying device 4 can be constituted by a heater utilizing radiant heat such as a heating wire or a heater utilizing hot air.

The internal temperature of the heating / drying device 4 when passing the continuous fiber bundle A to which the thermoplastic resin emulsion is adhered is about 150 to 400 ° C., and the optimum temperature differs depending on the type of the thermoplastic resin emulsion used. Therefore, for example, in the case of the AS resin emulsion,
To 400 ° C., but in the case of SB latex, heat resistance is not good and heat shrinkage occurs at high temperature.
It is desirable to dry-melt at 00 to 150 ° C.

In the drying and melting step, the evaporation of the moisture in the adhered thermoplastic resin emulsion and the homogenization of the resin are carried out to ensure the surface coating of the monofilament of the continuous fiber bundle A. When heating the emulsion, the melt viscosity and heat resistance of the thermoplastic resin to be used should be taken into consideration, and especially, rapid exposure to a high-temperature atmosphere should be avoided.

The dried and melted continuous fiber bundle B is immediately introduced into the twisting machine 5 without cooling, and the continuous fiber bundle B is twisted in the axial direction and twisted.

As shown in the figure, the twisting machine 5 has a pair of pinch rollers 6, 6 for holding a continuous fiber bundle B coated with a thermoplastic resin by drying and melting, built in a casing 7. The pulley 8 provided and the pulley 10 directly connected to the motor 9 are connected by a belt 11 to transmit the rotation of the motor 9 to the casing 7. The casing 7 is rotated by driving the motor 9. Continuous fiber bundle B pinched by a pair of pinch rollers 6 and 6
Is rotated and twisted.

In the twisting treatment in this step, the number of twists per meter of the continuous fiber bundle B is set to preferably 5 to 50 times / m, more preferably 10 to 30 times / m by rotating the casing 7. Is what you do.

The continuous fiber bundle C obtained by the twisting process has a large amount of thermoplastic resin coating the individual monofilaments sandwiched between the twisted monofilaments, and is surely integrated without separating. Can be held.

The twisted continuous fiber bundle C is then introduced into a cooling tank 12 filled with water and cooled.
The cutter 15 composed of a rotary blade and the support roll 1 are taken up by a pair of take-up rolls 13 arranged after the cutter roll 2.
6 into the pelletizer 14 with 3 to 20 m
m, and is stocked in the pellet stocker 17 as target resin pellets P.

The resin pellet P thus obtained is mixed with a matrix resin composed of a thermoplastic resin so as to have a desired fiber concentration to obtain a molding composition of the present invention. The composition for use can be made into various molded articles by a usual molding method.

The matrix resin used in the molding composition is preferably compatible with the above-mentioned thermoplastic resin emulsion. Examples thereof include AS resin, polystyrene resin, acrylonitrile / styrene / butadiene copolymer resin, polyethylene, polypropylene and polycarbonate. , Polyphenylene ether, nylon and the like.

In molding a high-concentration fiber pellet (concentrate) mixed with such a matrix resin, there is a difference in specific gravity between the two and a difference in the shape of the pellet. It is desirable to use a metering device and a mixing device so as to obtain a glass concentration.

[0032]

According to the resin pellets of the present invention, a continuous fiber bundle composed of monofilaments whose surface is uniformly coated with a thermoplastic resin is twisted, cut into a predetermined length and pelletized. Are effectively bonded and are not released from the continuous fiber bundle.

The method for producing resin pellets according to the present invention does not use a large-scale apparatus such as an extruder, but includes an immersion tank for adhering a thermoplastic resin emulsion to a monofilament constituting a continuous fiber bundle; A heating dryer for heating and melting the continuous fiber bundle to which the emulsion is attached, a twisting machine for preventing the looseness by cutting the attached thermoplastic resin between the monofilaments,
By simply using a cooler, a pelletizer, and the like, it is possible to obtain high-quality resin pellets in which the coated resin is not released.

In the molding composition of the present invention, the same or similar thermoplastic resin as the thermoplastic resin emulsion used for the production of the pellets is blended as a matrix resin with the above resin pellets. By molding, an excellent molded product without releasing the coating resin can be obtained.

[0035]

The present invention will be described in more detail with reference to the following examples. <Examples 1 to 3 and Comparative Examples 1 and 2> A continuous fiber bundle A made of glass fiber rovings using 2,000 monofilaments having a thickness of 13 μφ as one bundle and using five bundles was manufactured by the manufacturing apparatus 1 shown in FIG. The fiber is continuously introduced into the immersion tank 2 at a speed of 10 m / min while being spread to individual monofilaments, and is passed through the AS resin emulsion having a solid content of 40% by weight charged in the immersion tank 2 to thereby obtain individual fibers of the continuous fiber bundle A. The AS resin emulsion was uniformly attached to the surface of the monofilament.

Next, this is introduced into the heating / drying device 4,
Drying at a temperature of 380 ° C. From a glass fiber roving with a uniform coating of AS resin formed on the surface to evaporate the moisture in the AS resin emulsion attached to the surface of the continuous fiber bundle A and to make the melting of the resin uniform. The continuous fiber bundle B was continuously obtained.

The continuous fiber bundle B coated with the AS resin exiting the heating / drying unit 4 is immediately introduced into the twisting machine 5 without cooling, and twisted at a rate of 30 turns / m. Then, the continuous fiber bundle C was formed, and then guided to the cooling bath 12 for cooling. After that, the pellet was cut to a length of 9 mm by the pelletizer 14 to obtain a resin pellet P. This resin pellet P
Had a glass fiber content of 80% by weight.

Examples 1 to 3 in which the resin pellet P and the AS resin were used as the matrix resin, and the blending amounts thereof were changed.
3 was obtained. Using these molding compositions, a molded article having a predetermined shape was formed by a usual injection molding method, and various physical properties of the molded article were measured.

As a comparative example, a molding composition (Comparative Example 1) of resin pellets (hereinafter referred to as non-twisted pellets) obtained by omitting the twisting treatment when producing the resin pellets P, and A molding composition (Comparative Example 2) using resin pellets (hereinafter simply referred to as chopped strands) obtained by extruding glass fiber chopped strands and a thermoplastic resin with an extruder and dispersing glass fibers in the thermoplastic resin is used. The measured values of the physical properties of the molded product were similarly measured.

The results are shown in Table 1 together with the above amounts.
Shown in According to the results of [Table 1], the physical properties of the molded articles using the molding resin compositions of Examples 1 to 3 are superior to those of Comparative Examples 1 and 2. Especially,
The molded articles of Examples 1 and 2 in which the resin pellets P were blended at a high concentration could have better physical property values.

On the other hand, in the molded product of Comparative Example 1, the glass fiber of the resin pellet was liberated to form fluff, because the glass fiber of the resin pellets was overwhelmingly poor because of no twisting. It was recognized that it became apparent. In Table 1, the numbers in the hue column indicate the order in which the yellow discoloration of the molded product is strong, and the larger the number, the stronger the yellow color.

In Table 1, the units of the test items are as follows. Glass concentration ・ ・ ・ wt% Tensile strength ・ ・ ・ kgf / cm ² Elongation ・ ・ ・% Flexural strength ・ ・ ・ kgf / cm ² Elasticity ・ ・ ・ kgf / cm ² Izod impact value ・ ・ ・ kgf- cm / cm ² [Margin below]

[0043]

[0044]

The resin pellets of the present invention are formed by twisting in the axial direction a continuous fiber bundle in which the surface of individual monofilaments is uniformly coated with a thermoplastic resin and cut into a predetermined size. Therefore, the thermoplastic resin does not bite firmly between the monofilaments and is not released, and when this is mixed with the matrix resin and molded, the released monofilaments do not form fluff balls and become defective products And can maintain excellent strength.

According to the method for producing resin pellets of the present invention, a continuous fiber bundle for obtaining high-quality resin pellets in which a thermoplastic resin does not bite firmly between monofilaments and is released is applied to a large-scale apparatus such as an extruder. Can be simply and easily manufactured by using only a dipping tank, a heater / dryer, a twister, a cooler, a pelletizer, and the like for attaching a thermoplastic resin emulsion.

The molding composition of the present invention is used as a matrix resin in a resin pellet obtained from a continuous fiber bundle in which the thermoplastic resin does not bite firmly between the monofilaments and is not released. Since the same or similar thermoplastic resin as the plastic resin emulsion is blended and molded, the obtained molding composition is hard to crack and has excellent shape and excellent quality.

[Brief description of the drawings]

FIG. 1 is a process chart for producing a resin pellet of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Manufacturing apparatus of resin pellet 2 Dipping tank 4 Heat dryer 5 Twisting machine 6 Pinch roller 7 Casing 12 Cooling tank 13 Take-off roller 14 Pelletizer 17 Pellet stocker

Claims (6)

[Claims] After dipping in a thermoplastic resin emulsion, the attached thermoplastic resin is dried and melted to twist a continuous fiber bundle coated with the resin, cut into a predetermined length, and pelletized. Characteristic resin pellets. 2. The resin pellet according to claim 1, wherein the thermoplastic resin emulsion is an acrylonitrile-styrene copolymer emulsion. 3. The opened continuous fiber bundle is immersed in a thermoplastic resin emulsion, the attached thermoplastic resin is dried and melted, and the resin-coated continuous fiber bundle is twisted, cooled, and then cooled. A method for producing resin pellets, comprising cutting into lengths and pelletizing. 4. The twisting of the continuous fiber bundle is performed 5 to 50 times /
4. The method for producing resin pellets according to claim 3, wherein the number of twists is m. 5. After dipping in a thermoplastic resin emulsion, the attached thermoplastic resin is dried and melted, and a continuous fiber bundle coated with the resin is twisted and cut into a predetermined length to obtain a resin pellet. A molding composition comprising a thermoplastic resin. 6. The molding composition according to claim 5, wherein the thermoplastic resin comprises an acrylonitrile / styrene copolymer.