JP2009221427A - Method for manufacturing glass fiber-reinforced resin pellet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a glass fiber-reinforced resin pellet with which molding defectives on injection molding are controlled even in the case of using a high melting point resin such as a liquid crystalline polymer as a thermoplastic resin, and the molded product after injection molding retains glass fibers of a long length. <P>SOLUTION: This method for manufacturing the glass fiber-reinforced resin pellet comprises: a pultrusion step of pultruding a glass fiber bundle obtained by bundling a plurality of glass fibers with a sizing agent with a thermally melted thermoplastic resin through a through-hole formed in a die; a first pelletizing step of pelletizing the resin-impregnated glass fiber bundle obtained in the pultrusion step by cutting; and a second pelletizing step of kneading the pellet obtained in the first pelletizing step together with the thermally melted thermoplastic resin and pelletizing the kneaded matter. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing glass fiber reinforced resin pellets.

  As one of the methods for producing glass fiber reinforced resin pellets, for example, a strand obtained by adding a sizing agent to a spun glass fiber, or a roving obtained by combining the strands is used as a glass fiber bundle. A method is known in which chopped strands cut to about 20 mm are kneaded with a thermoplastic resin and then pelletized.

  As another method, for example, a method of impregnating the above glass fiber bundle with a thermoplastic resin and then cutting it to obtain glass fiber reinforced resin pellets is known.

  The glass fiber reinforced resin pellet obtained by the above-mentioned method is processed as a molded product by injection molding. Various studies have been conducted to increase the mechanical strength of the molded product.

  For example, in Patent Document 1, in order to obtain a glass fiber reinforced resin having high mechanical strength, the ratio A / B of the adhesion amount (A) of the silane coupling agent to the glass fiber and the adhesion amount (B) of the polysiloxane is set. A technique using a sizing agent of 1 to 20 has been proposed.

Further, for example, in Patent Document 2, a mixture of a reinforced long fiber having a fiber length of 3 to 100 mm and longer than the pellet length and a reinforced short fiber shorter than that, and a thermoplastic resin powder having a diameter of 1 mm or less. Or / and fiber length: a raw material containing thermoplastic resin fibers having a length of 3 to 25 mm is heated to make the resin component into a molten state, and then charged into an extruder, extruded from the die and a strand having a diameter of 2 to 10 mm. And, this is cut into a length of 5 to 25 mm to be pelletized, so that a reinforcing fiber longer than the pellet length is contained in the pellet to enhance the reinforcing effect.
JP 2003-238213 A JP-A-6-254847

  However, in the conventional methods as described above, when a resin having a high melting point such as a liquid crystal polymer is used as the thermoplastic resin, there are problems as described below.

  That is, a glass fiber reinforced resin pellet using a resin having a high melting point such as a liquid crystal polymer needs to be molded at a high temperature when it is injection molded to obtain a molded product. For this reason, there has been a problem that the sizing agent component for converging the glass fibers at the time of molding is decomposed and gas is generated, which causes molding defects such as swelling.

  Therefore, when a resin having a high melting point such as a liquid crystal polymer is used as the thermoplastic resin, it is necessary to reduce the amount of the sizing agent.

  However, in the method using chopped strands, if the amount of sizing agent applied to the spun glass fiber is reduced, fluffing occurs in the strands in the chop strand manufacturing process, or chipped strands are obtained due to defective strand cutting. There was a problem that it became difficult.

  On the other hand, since the glass fiber bundle is impregnated with a thermoplastic resin and then cut, there is almost no processing step that strongly damages the glass fiber bundle, so the amount of sizing agent applied to the spun glass fiber Can be reduced. However, a resin having a high melting point such as a liquid crystal polymer usually has a poor impregnation property with respect to glass fibers. Therefore, when such a resin is used, glass fiber reinforced resin pellets cannot be stably produced, or by injection molding. There was a problem that it was difficult to produce a molded product.

  Accordingly, an object of the present invention is to provide a method for producing glass fiber reinforced resin pellets capable of suppressing molding defects during injection molding even when a resin having a high melting point such as a liquid crystal polymer is used as the thermoplastic resin. Another object of the present invention is to provide a method for producing a molded product using the glass fiber reinforced resin pellets produced by the production method.

  The present invention includes a thermoplastic resin obtained by thermally melting a glass fiber bundle, a drawing process of drawing through the through hole of a die having a through hole, and a resin impregnated glass fiber bundle obtained by the drawing process by cutting the pellet. Glass fiber reinforced resin pellets comprising: a first pelletizing step to be converted; and a second pelletizing step in which the pellets obtained in the first pelletizing step are heat-kneaded and the thermoplastic resin is thermally melted to be pelletized. A manufacturing method is provided.

  That is, the present invention is obtained by impregnating a thermoplastic resin into a bundle of glass fibers such as a strand obtained by adding a sizing agent to a spun glass fiber and bundling, or a roving obtained by combining a plurality of strands. A first pelletizing step for obtaining the first pellets obtained, and a second pelletizing step for heat-melting and kneading the thermoplastic resin of the first pellets and then pelletizing again. . In the method for producing glass fiber reinforced resin pellets of the present invention, since the cutting step for pelletization is performed after impregnating the thermoplastic resin, the amount of sizing agent applied to the spun glass fibers can be reduced. It is. Therefore, even when a resin having a high melting point such as a liquid crystal polymer is used as the thermoplastic resin, molding defects such as blistering caused by decomposition gas of the sizing agent component can be suppressed. Moreover, the strength reduction of the molded product resulting from the decomposition gas of the sizing agent component can be suppressed. Also, by impregnating a molten glass fiber bundle with a thermoplastic resin to obtain pellets, the pellets are kneaded again, and even when a resin having a high melting point such as a liquid crystal polymer is used, the resin is suppressed while preventing glass fibers from being crushed. Can be sufficiently impregnated. Therefore, the strength of the molded product can be improved. Furthermore, if the glass fiber reinforced resin pellets manufactured by the manufacturing method of the present invention are used, the fiber length in the molded product after injection molding can be kept long, so that the strength of the molded product can be increased.

In the method for producing glass fiber reinforced resin pellets of the present invention, the thermoplastic resin in the first pelletizing step is the first thermoplastic resin, and the first pellet is the second thermoplastic resin in the second pelletizing step. It is preferable that the first thermoplastic resin and the second thermoplastic resin are melted by heat kneading together with the resin. By doing in this way, the content ratio of the glass fiber bundle and thermoplastic resin in a 1st pellet process or a 2nd pelletization process can be set appropriately, and the intensity | strength of a molded article can further be improved. .
In addition, in the manufacturing method of the glass fiber reinforced resin pellet of this invention, it is preferable that the said 1st thermoplastic resin and 2nd thermoplastic resin are the same resin compositions.

  The thermoplastic resin used in the production method of the present invention may be a thermoplastic resin having a melting temperature of 200 ° C. or higher, such as a liquid crystal polyester resin. The melting temperature in the present invention means an endothermic peak temperature when the temperature of the resin composition is raised and the endothermic temperature is measured by thermal analysis such as a differential scanning calorimeter.

  According to the present invention, even when a thermoplastic resin having such a melting temperature is used, defective molding at the time of injection molding such as swelling caused by the decomposition gas of the sizing agent component can be suppressed. In addition, it is possible to suppress the reduction in strength of the molded product due to the decomposition gas of the sizing agent component and to sufficiently impregnate the thermoplastic resin. Since the fiber length in the molded product after injection molding can be kept long, the strength of the molded product can be increased.

Further, the glass fiber bundle used in the production method of the present invention preferably has a loss on ignition Wa of 0.10 [wt%] or less when heated to 400 ° C, and is strong when heated to 625 ° C. The heat loss Wb is more preferably 0.10 [wt%] or less. In the present invention, the loss on ignition Wa, Wb of the glass fiber bundle is calculated by the following formula (1) or (2).
Wa = ((M1-M2) / M1) × 100 [%] (1)
Wb = ((M1-M3) / M1) × 100 [%] (2)
However,
M1: A glass fiber bundle in the vicinity of about 5 g was dried at 105 ± 5 ° C. for 6 hours and completely dried, then placed in a desiccator and allowed to cool to room temperature.
M2: The mass (g) of the heated glass fiber bundle heated in the heating furnace maintained at 400 ± 20 ° C. for 15 minutes, then removed from the heating furnace, and allowed to cool in a desiccator.
M3: The mass (g) of the heated glass fiber bundle heated in the heating furnace maintained at 625 ± 20 ° C. for 15 minutes, then removed from the heating furnace, and allowed to cool in a desiccator.

  By using such a glass fiber bundle, that is, a glass fiber bundle with a small amount of sizing agent that causes decomposition gas, molding defects such as blistering caused by decomposition gas, and strength reduction of the molded product are reduced. Can be further suppressed.

  The present invention relates to a method for manufacturing a molded article, in which glass fiber reinforced resin pellets obtainable by the above-described manufacturing method are injection-molded.

  If glass fiber reinforced resin pellets obtained by the above-mentioned production method are injection-molded, molding defects caused by the decomposition gas of the sizing component and the strength of the molded product due to the decomposition gas of the sizing component The decrease can be suppressed. Furthermore, such a molded product obtained by injection molding of glass fiber reinforced resin pellets has a long glass fiber length and a high strength.

  According to the present invention, even when a resin having a high melting temperature, such as a liquid crystal polymer, is used as the thermoplastic resin, molding defects during injection molding can be suppressed, and the glass fiber fibers contained in the molded product after injection molding A method for producing a long glass fiber reinforced resin pellet can be provided. Moreover, the manufacturing method can provide the manufacturing method of a molded article using the manufactured glass fiber reinforced resin pellet.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as necessary. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

  As a preferred embodiment of the method for producing glass fiber reinforced resin pellets, a plurality of glass fibers to which a sizing agent is attached are bundled into a glass fiber bundle, and the glass fiber bundle is penetrated together with a first thermoplastic resin that is heat-melted. Obtained by a drawing step of drawing through the through hole of the die formed with holes, a first pelletizing step of cutting and pelletizing the resin-impregnated glass fiber bundle obtained in the drawing step, and a first pelletizing step And a second pelletizing step in which the pellets are kneaded with the second thermoplastic resin that has been melted and then pelletized. In order to improve the strength of the molded product, the first thermoplastic resin and the second thermoplastic resin are preferably the same resin composition. In the second pellet step, the first thermoplastic resin may be heated to melt and knead the first thermoplastic resin without adding the second thermoplastic resin.

  The glass fiber bundle used in the first pelletizing step can be manufactured by the following steps, for example.

  First, glass fiber is manufactured by melting glass fiber raw glass and drawing the molten raw glass from the bushing. Thereafter, a coating solution of a sizing agent containing a silane coupling agent, a lubricant, a film forming agent and the like is applied to the glass fiber, and 50 to 8000 glass fibers are bundled as a bundle, and then wound and dried to form a strand. To manufacture a roll. And the glass fiber bundle in which 1000-30000 glass fibers were bundled is obtained by further combining the 2-50 strands. In some cases, the strand may be used as it is as a glass fiber bundle without being combined.

  Examples of the glass fiber raw glass include E glass, S glass, low dielectric glass, and C glass. From the viewpoint of easy fiberization, it is preferable to use E glass. The fiber diameter is preferably 3 to 17 μm.

  Silane coupling agents are used to improve the interfacial adhesion between glass fibers and thermoplastic resins impregnated into glass fibers. Usually, organic acids such as acetic acid, formic acid and lactic acid, water, etc. Used by dissolving in As the silane coupling agent, known ones can be used, for example, a silane coupling agent having an unsaturated double bond such as vinyltriethoxysilane, vinyltrimethoxysilane, γ- (methacryloyloxypropyl) trimethoxysilane; Silane coupling agents having an epoxy group such as β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-glycidyloxypropylmethyldiethoxysilane; γ-mercaptopropyltrimethoxy Silane coupling agents having a mercapto group such as silane; γ-aminopropyltriethoxysilane, N-β- (aminoethyl) γ-aminopropyltrimethoxysilane, N-β- (N-vinylbenzylaminoethyl) -γ -Aminopropyltri Silane coupling agent having an amino group such as Tokishishiran can be exemplified.

  The lubricant is used for suppressing wear caused by friction between glass fibers. As the lubricant, for example, a condensate of tetraethylenepentamine and stearic acid is used.

  The film forming agent is used for bundling glass fibers and protecting the surface. As the film forming agent, any known film forming agent can be used as long as it is capable of forming glass fibers. Examples of known film forming agents include urethane resins, acrylic resins, epoxy resins, and vinyl acetate resins. In some cases, the sizing agent may not contain a film forming agent.

  The amount of the sizing agent adhering to the glass fiber affects the values of ignition losses Wa and Wb at 400 ° C. and / or 625 ° C. calculated by the above formula (1) and / or (2). Therefore, it is preferable to adjust the adhesion amount of the sizing agent in consideration of the ignition loss value.

  The glass fiber bundle preferably has an ignition loss value Wa at 400 ° C. of 0.10 [% by weight] or less. Such a glass fiber bundle has a small content of the sizing agent component that causes decomposition gas, and thus further suppresses molding defects such as blistering caused by decomposition gas and reduction in strength of the molded product. can do.

  Further, the glass fiber bundle preferably has an ignition loss value Wb at 625 ° C. of 0.10 [% by weight] or less. When such a glass fiber bundle is used, the interfacial adhesion between the glass fiber and the thermoplastic resin is further improved. Therefore, the strength of the molded product can be improved.

  FIG. 1 is a schematic view of a manufacturing apparatus 100 used in the drawing process and the first pelletizing process.

  The manufacturing apparatus 100 includes a thermoplastic resin tank 34 in which a hot-melt thermoplastic resin 10a is accommodated, a die 30 in which a through hole 31 through which the glass fiber bundle 21 is passed together with the hot-melt thermoplastic resin 10a, and a thermoplastic resin. A puller 40 for pulling out the glass fiber bundle impregnated with the resin from the die 30 is provided, and these are used in the drawing step in the present invention.

  A wound body 22 around which a glass fiber bundle 21 to be introduced into the die 30 is wound is disposed on the upstream side of the die 30. The puller 40 located on the downstream side of the die 30 is a so-called caterpillar puller in which a glass fiber bundle impregnated with a thermoplastic resin is sandwiched from above and below by a rotating roller.

  In the drawing process, first, the puller 40 is driven to rotate, and the glass fiber bundle 21 is pulled out from the wound body 22.

  Then, the drawn glass fiber bundle 21 is introduced into the through hole 31 of the die 30 and the thermoplastic resin 10a that has been thermally melted is guided to the through hole 31 using a pump or the like. In the die 30, the melted thermoplastic resin 10 a is impregnated around and inside the glass fiber bundle 21, and the thermoplastic resin is molded into a shape corresponding to the outlet side cross-sectional shape of the through-hole 31 by the rotational drive of the puller 40. The glass fiber bundle impregnated with the resin is pulled out from the die 30.

  The drawing speed is preferably about 5 to 30 m / min. Increasing the speed further tends to cause problems such as a decrease in resin impregnation property and a cutting failure in a subsequent cutting step. The glass fiber bundle may be twisted during drawing.

  Although one wound body 22 is used in FIG. 1, a plurality of glass fiber bundles 21 may be introduced into the die 30 using a plurality of wound bodies 22. Further, a cooling means for promoting solidification of the hot-melted thermoplastic resin 10a may be installed between the die 30 and the puller 40. This may be performed by touching a liquid such as water or by air cooling. Further, a molding means for adjusting the cross-sectional shape of the glass fiber bundle 21 to which the thermoplastic resin is attached may be installed between the die 30 and the puller 40.

  The temperature at which the thermoplastic resin is melted is usually higher than the temperature at which the thermoplastic resin melts and below the temperature at which the thermoplastic resin is not decomposed or altered.

  Although there is no restriction | limiting in particular in a thermoplastic resin, The thermoplastic resin whose melting temperature is 200 degreeC or more is preferable. When such a resin is used, the effect of the present invention is particularly remarkable.

  Examples of the thermoplastic resin having a melting temperature of 200 ° C. or higher include liquid crystal polyester resin, PEEK (polyether ether ketone) resin, and PES (polyether sulfone) resin.

  The amount of the thermoplastic resin to be impregnated is preferably 20 to 300 parts by mass, more preferably 30 to 200 parts by mass with respect to 100 parts by mass of the glass fiber bundle. When the amount of the thermoplastic resin is less than 20 parts by mass with respect to 100 parts by mass of the glass fiber bundle, the fiber length of the glass fiber is shortened by kneading in the second pelletizing step, and the strength of the molded product tends to be reduced. When the amount is more than part by mass, the strength of the molded product tends to decrease due to a decrease in the proportion of glass fibers in the molded product.

  The manufacturing apparatus 100 also includes a cutting machine 50 that rotates the blade with the driving force of the motor M to cut the glass fiber bundle impregnated with the thermoplastic resin to obtain the glass fiber resin reinforced pellet 200. Applies to one pelletization process. The cutting machine 50 is not particularly limited as long as it can cut the glass fiber bundle impregnated with the thermoplastic resin, and a known device is used.

  In the first pelletizing step, the glass fiber bundle impregnated with the thermoplastic resin and solidified into a state suitable for cutting is cut by the cutting machine 50 to obtain the glass fiber reinforced resin pellet 200. Here, the pellet length can be adjusted by adjusting the rotational speed and line speed of the cutter. The pellet length is 2 to 50 mm, more preferably 5 to 20 mm. When cut shorter than 2 mm, the fiber length of the glass fiber in the molded product after injection molding is shortened, so that the strength of the glass fiber reinforced resin molded product tends to decrease. Moreover, when it cut | disconnects longer than 50 mm, in the 2nd pelletization process performed after the 1st pelletization, clogging etc. will arise and there exists a tendency for workability | operativity to fall.

  FIG. 2 is a perspective view of the pellet 200 obtained in the first pelletizing step. FIG. 3A is a front view of the pellet 200 obtained in the first pelletizing step, and FIG. 3B is a side view thereof.

  As shown in FIGS. 2 and 3, the pellet 200 is obtained by arranging a plurality of glass fibers 20 included in the glass fiber bundle 21 in one direction in the thermoplastic resin 10. Further, as apparent from FIG. 3B, the end face of the glass fiber 20 is not covered with the thermoplastic resin. 3B shows only one side surface (end surface), the glass fiber 20 has reached the other side surface (end surface), and the end surface is not covered with the thermoplastic resin.

  FIG. 4 is a schematic view of a manufacturing apparatus 500 used in the second pelletizing step. The manufacturing apparatus 500 includes a twin-screw extruder 64 for kneading the pellet 200 and the thermoplastic resin 300, a cooling means 66 for cooling the kneaded product of the pellet 200 and the thermoplastic resin 300, and a cutting means 68 for cooling and cutting the kneaded product. And.

  In the second pelletizing step, the pellet 200 manufactured in the first pelletizing step and the thermoplastic resin 300 are charged into the twin screw extruder 64 and kneaded. Note that only the pellet 200 may be charged into the twin screw extruder 64 and kneaded without adding the thermoplastic resin 300.

  By performing the second pelletizing step using the first pellet, the impregnation property of the resin into the glass fiber bundle can be enhanced while suppressing the crushing of the glass fiber 20 by the twin screw extruder 64, and the glass fiber is reinforced. When a resin molded product is manufactured, higher strength can be obtained.

When the pellet 200 and the thermoplastic resin 300 are added, it is preferable to use 10 to 200 parts by mass of the thermoplastic resin 300 with respect to 100 parts by mass of the pellet 200. Moreover, it is preferable that the composition of the pellet 400 finally obtained becomes 50-300 mass parts of thermoplastic resins with respect to 100 mass parts of glass fiber bundles.
In the second pelletizing step, when only the pellet 200 is kneaded without introducing the thermoplastic resin 300, the pellet 200 is 50 to 300 parts by mass of the thermoplastic resin with respect to 100 parts by mass of the glass fiber bundle. It is preferable that

  After kneading, the kneaded product extruded from the twin screw extruder 64 is cooled by the cooling means 66. The glass fiber bundle in which the resin is solidified in a state suitable for cutting after being cooled is cut by the cutting means 68 to obtain a glass fiber reinforced resin pellet 400. Here, the pellet length can be adjusted by adjusting the rotational speed and line speed of the cutter. The pellet length is 0.5 to 15 mm, more preferably 1 to 5 mm, and still more preferably 2 to 4 mm. When cut shorter than 0.5 mm, the fiber length of the glass fiber in the molded product after injection molding is shortened, so that the strength of the glass fiber reinforced resin molded product tends to decrease. Moreover, when it cut | disconnects longer than 10 mm, when manufacturing a molded article by injection molding, clogging etc. will arise and there exists a tendency for workability | operativity to fall.

  In FIG. 4, a twin screw extruder is used for kneading, but any known apparatus can be used as long as the pellet 200 and the thermoplastic resin can be kneaded. Moreover, in FIG. 4, although the cooling tank which touches liquids, such as water, is used as a cooling means, you may perform cooling by air cooling. The cutting means 68 is not particularly limited as long as it can cut the glass fiber bundle in which the resin is solidified, and a known device is used.

  Thus, the mass ratio of the glass fiber bundle 21 and the thermoplastic resin 10a in the first pelletizing step and the mass ratio of the pellet 200 and the thermoplastic resin 300 in the second pelletizing step are the workability of each step. In consideration of the mass ratio of the glass fiber bundle and the thermoplastic resin in the glass fiber reinforced resin pellet 400, an optimal mass ratio in each step may be set.

  FIG. 5 is a schematic view of an injection molding machine 600 for producing a molded product.

  The injection molding machine 600 includes a hopper 60 that is an inlet for resin pellets, a cylinder 70, a heater 75, and a screw 80. A mold 90 is installed at the outlet of the cylinder 70.

  The molded product can be manufactured by putting the glass fiber reinforced resin pellet 600 into the hopper 60 and performing injection molding. At this time, if necessary, thermoplastic resin pellets may be further added.

  As the molded product, the glass fiber reinforced resin pellet 400 is put into the hopper 60 of the injection molding machine 300 and the cylinder 70 is heated by the heater 75 to melt the thermoplastic resin in the glass fiber reinforced resin pellet 400. The melted resin and glass are mixed with the inner screw 80 and sent to the tip of the cylinder 70. The heating temperature may be set to a temperature that is about 10 to 30 ° C. higher than the melting temperature of the thermoplastic resin.

  Subsequently, pressure is applied to the molten glass fiber reinforced resin and the mold 90 is driven. Thereafter, the resin is cooled and crystallized in the mold 90, and the glass fiber reinforced resin molded product is taken out. Through the above steps, a glass fiber reinforced resin molded product can be produced.

  Hereinafter, preferred examples will be described in more detail, but the present invention is not limited to these examples.

Example 1
[Production of glass fiber bundle]
Silane coupling agent (γ-aminopropyltriethoxysilane) 0.5% by mass, pH adjusting agent (acetic acid) 0.2% by mass, lubricant (condensate of tetraethylenepentamine and stearic acid) 0.03% by mass A sizing aqueous solution containing was prepared. The adjusted sizing aqueous solution was applied to glass fibers (E glass filaments having a diameter of 11 μm), and 1500 glass fibers were bundled to form glass strands. Furthermore, after drying at 120 ° C. for 8 hours, ten glass strands were combined to prepare a glass fiber bundle.

  About the glass strand produced by the above-mentioned method, when the ignition loss value Wa in 400 degreeC and the ignition loss value Wb in 625 degreeC were measured, Wa = 0.06 [weight%], Wb = 0.08 [weight%]. ]Met. The results are shown in Table 1.

[Production of molded products]
A glass fiber bundle produced by the above-mentioned method using a long fiber thermoplastic resin pellet production apparatus was drawn at a rate of 15 m / min, and a liquid crystal polyester resin (econol-based liquid crystal polyester: melting temperature 330) was added to 60 parts by mass of the glass fiber bundle. C.) 40 parts by mass were impregnated at 350.degree. C. and then cut with a pelletizer to obtain a pellet having a length of 12 mm. Further, 50 parts by mass of the pellets and 50 parts by mass of a liquid crystal polyester resin having the same resin composition as the liquid crystal polyester resin were kneaded at 350 ° C. by an extruder, and then cut by a pelletizer to obtain a pellet having a length of 3 mm. . The pellet was injection molded at 350 ° C. to produce a glass fiber reinforced thermoplastic resin molded product. In this case, with respect to 100 parts by mass of the obtained molded product, the glass fiber bundle in the molded product is 30 parts by mass, and the liquid crystal polyester resin in the molded product is 70 parts by mass.

(Comparative Example 1)
[Production of glass fiber bundle]
Silane coupling agent (γ-aminopropyltriethoxysilane) 0.5% by mass, acetic acid 0.2% by mass, lubricant (condensate of tetraethylenepentamine and stearic acid) 0.03% by mass, film forming agent ( A sizing aqueous solution containing 1.0% by mass of urethane resin (RC30K manufactured by NSC Japan, solid content: 55%) was prepared. The adjusted sizing aqueous solution was applied to glass fibers (E glass filaments having a diameter of 11 μm), and 1500 glass fibers were bundled to form glass strands. Furthermore, after drying at 120 ° C. for 8 hours, ten glass strands were combined to prepare a glass fiber bundle.

  About the glass strand produced by the above-mentioned method, when the ignition loss value Wa in 400 degreeC and the ignition loss value Wb in 625 degreeC were measured, Wa = 0.20 [weight%], Wb = 0.25 [weight%]. ]Met. The results are shown in Table 1.

[Production of molded products]
The glass fiber bundle obtained by the above-described method was cut to produce a chopped strand having a length of 3 mm. And after knead | mixing 70 mass parts of liquid crystalline polyester resin (Econol type | system | group liquid crystalline polyester: melting temperature 330 degreeC) at 350 degreeC with an extruder at 30 mass parts of the obtained chopped strand, it cut | disconnects with a pelletizer, and length 3mm Pellets were obtained. The pellets were injection molded at 350 ° C. to obtain a glass fiber reinforced thermoplastic resin molded product.

(Comparative Example 2)
[Production of glass fiber bundle]
A glass fiber bundle was produced in the same manner as in Example 1. The results of Wa and Wb were the same as in Example 1. The results are shown in Table 1.

[Production of molded products]
The obtained glass fiber bundle was cut to produce a chopped strand having a length of 3 mm. The obtained chop strand was frequently fuzzy. In addition, when 30 parts by mass of the chopped strands were kneaded with 70 parts by mass of a liquid crystalline polyester resin (Econol-based liquid crystalline polyester: melting temperature 330 ° C.) at 350 ° C. by an extruder, the chopped strands became cottony. The kneading was poor and pellets could not be produced.

(Comparative Example 3)
[Production of glass fiber bundle]
A glass fiber bundle was produced in the same manner as in Example 1. The results of Wa and Wb were the same as in Example 1. The results are shown in Table 1.

[Production of molded products]
Using a long fiber thermoplastic resin pellet manufacturing apparatus, 60 parts by mass of a glass fiber bundle produced by the above-described method is impregnated with 40 parts by mass of a liquid crystal polyester resin (Econol type liquid crystal polyester: melting temperature 330 ° C.) at 350 ° C. After that, the pellet was cut by a pelletizer to obtain a pellet having a length of 3 mm. Further, 50 parts by mass of the pellets and 50 parts by mass of the liquid crystalline polyester resin were kneaded at 350 ° C. using an injection molding machine and injection molded to produce a glass fiber reinforced thermoplastic resin molded product. In the obtained molded product, defective glass fiber dispersion occurred frequently, resulting in defective molding.

(Comparative Example 4)
[Production of glass fiber bundle]
A glass fiber bundle was produced in the same manner as in Example 1. The results of Wa and Wb were the same as in Example 1. The results are shown in Table 1.

[Production of molded products]
The obtained glass fiber bundle was cut to produce a cut fiber having a length of 0.1 mm. 70 parts by mass of liquid crystal polyester resin (Econol-based liquid crystal polyester: melting temperature 330 ° C.) is kneaded at 350 ° C. by an extruder and then cut by a pelletizer to 30 parts by mass of the cut fiber, and pellets having a length of 3 mm are obtained. Obtained. This pellet was injection molded at 350 ° C. to obtain a glass fiber reinforced thermoplastic resin molded product for a test piece for tensile strength evaluation described later.

(Evaluation of process suitability)
[Production of molded products]
About Example 1 and Comparative Examples 1-4, it was evaluated whether the manufacture of the molded product was possible. The case where the molded product could be produced was set as “OK”, and the case where it was difficult was set as “NO”. The results are shown in Table 1.

(Evaluation of molded products)
The molded product was evaluated for Example 1, Comparative Example 1 and Comparative Example 4 in which the molded product could be produced.

[Tensile strength]
The tensile strength was measured according to ASTM standard ASTM D-638 “Standard Test Method for Tensile Properties of Plastics”. The measurement results are shown in Table 1.

[Fukure]
The test piece used for the evaluation of the tensile strength was heated at 300 ° C. for 10 minutes with a hot air drier, then cooled, and the number of blisters (pieces / surface area of the test piece 10 cm ² ) was visually confirmed. In addition, a swelling shows the part which the swelling has produced on the test piece surface. The results are shown in Table 1.

[Measurement of melting temperature]
Using a differential scanning calorimeter, the thermoplastic liquid crystal polymer molded body was heated at a rate of 20 ° C./min to be completely melted, and then the melt was rapidly cooled to room temperature at a rate of 50 ° C./min. The endothermic peak temperature that appears when the temperature was raised at a rate of ° C./min was measured and taken as the melting temperature.

[Fiber length of glass fiber in molded product]
The molded product was heated at 625 ° C. for 125 minutes to decompose the thermoplastic resin component, and the remaining glass fibers were dispersed in chloroform so as not to break. Subsequently, the dispersed glass fiber was placed on a preparation, and the length of the glass fiber was measured using LUZEX-FS (Nireco Co., Ltd.) to obtain the fiber length of the glass fiber in the molded product. The results are shown in Table 1.

  As described above, Example 1 was injection-moldable without blistering. In Example 1, the fiber length of the glass fiber contained in the molded product after injection molding was also longer than those in Comparative Examples 1 and 4.

It is the schematic of the manufacturing apparatus 100 used for a drawing process and a 1st pelletization process. It is a perspective view of the pellet 200 obtained at a 1st pelletization process. (A) The front view of the pellet 200 obtained at a 1st pelletization process, (b) It is the same side view. It is the schematic of the manufacturing apparatus 500 used for a 2nd pelletization process. It is the schematic of the injection molding machine 600 for manufacturing a molded article.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Thermoplastic resin, 10a ... Hot melted thermoplastic resin, 20 ... Glass fiber, 21 ... Glass fiber bundle, 22 ... Winding thread body, 30 ... Dies, 31 ... Through-hole, 40 ... Puller, 60 ... Hopper, 64 DESCRIPTION OF SYMBOLS ... Twin screw extruder, 66 ... Cooling means, 68 ... Cutting means, 70 ... Cylinder, 75 ... Heater, 80 ... Screw, 90 ... Mold, 100 ... Manufacturing apparatus used for drawing process and first pelletizing process, 200 ... pellets, 400 ... glass fiber reinforced resin pellets, 500 ... manufacturing apparatus used in the second pelletizing step, 600 ... injection molding machine.

Claims (7)

A drawing step of drawing the glass fiber bundle through the through-hole of the die in which the through-hole is formed together with the thermoplastic resin obtained by hot melting,
A first pelletizing step of cutting and pelletizing the resin-impregnated glass fiber bundle obtained in the drawing step;
A second pelletizing step in which the pellets obtained in the first pelletizing step are heat-kneaded, the thermoplastic resin is thermally melted, and then pelletized;
A method for producing glass fiber reinforced resin pellets comprising A drawing step of drawing the glass fiber bundle through the through-hole of the die in which the through-hole is formed together with the first thermoplastic resin obtained by thermally melting the glass fiber bundle;
A first pelletizing step of cutting and pelletizing the resin-impregnated glass fiber bundle obtained in the drawing step;
The pellet obtained in the first pelletizing step is heat-kneaded together with the second thermoplastic resin, and the first thermoplastic resin and the second thermoplastic resin are thermally melted and then pelletized. Conversion process,
A method for producing glass fiber reinforced resin pellets comprising   The said thermoplastic resin is a manufacturing method of the glass fiber reinforced resin pellet of Claim 1 which is a thermoplastic resin whose melting temperature is 200 degreeC or more.   The manufacturing method of the glass fiber reinforced resin pellet of Claim 2 whose said 1st thermoplastic resin and / or said 2nd thermoplastic resin are thermoplastic resins whose melting temperature is 200 degreeC or more.   The said thermoplastic resin whose melting temperature is 200 degreeC or more is a manufacturing method of the glass fiber reinforced resin pellet of Claim 3 or 4 which is liquid crystal polyester resin.   The said glass fiber bundle is a manufacturing method of the glass fiber reinforced resin pellet as described in any one of Claims 1-5 whose ignition loss when heated at 400 degreeC is 0.10 weight% or less. A step of producing glass fiber reinforced resin pellets by the production method according to any one of claims 1 to 6,
A step of injection molding the glass fiber reinforced resin pellet;
A method for producing a molded article comprising:

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