JP4844001B2 - Pellet material for injection molding and method for producing the same - Google Patents

Description

  The present invention relates to a pellet material for injection molding that exhibits excellent mechanical properties and conductive properties, and can be suitably used for, for example, electric and electronic members, automobile members, aircraft members, ship members, civil engineering materials, sports equipment members, and the like. The present invention relates to a pellet material for injection molding.

  Conventionally, since fiber reinforced resin is excellent in strength, rigidity, and heat resistance, it has been used suitably for members for transportation equipment such as automobiles, civil engineering materials, and sports equipment members. Carbon fibers, glass fibers, aramid fibers, etc. are used as the reinforcing fibers used in the fiber reinforced resin, but among them carbon fibers not only have light weight, high strength and high elastic modulus, but also have conductivity, so that they are lightweight. It is suitably used for members that require strength, rigidity, and conductivity. In addition, various molding methods such as autoclave molding, press molding, and RTM molding are used as the molding method for fiber reinforced resin, and injection molding using short fibers for reinforcing fibers is the molding time. Since it is short and excellent in moldability, it is suitably used for electric and electronic members and automobile members that require mass production.

  Typical examples of the use of automobile parts are exterior parts such as door moldings, frame frames for door mirrors, bumpers, etc., resin covers that cover the inner surface of engine rooms, electrical parts housings, and timing belt covers. Resin case. Since these automobile members are required to be lightweight in addition to rigidity and heat resistance, reinforcing fibers such as carbon fibers and nano-inorganic fillers are used. In particular, when a reinforcing fiber such as carbon fiber is used, a longer fiber length is preferable from the viewpoint of a reinforcing effect. In general, in injection molding using reinforcing fibers, reinforcing fibers and a thermoplastic resin are kneaded and extruded before injection molding to prepare reinforcing fiber-containing pellet materials. As described above, from the viewpoint of the reinforcing effect, it is preferable that the fiber length of the reinforcing fiber contained in the pellet material is long. However, if the fiber length is long, the fibers are entangled with each other, and a desired reinforcing effect cannot be expressed. There was a problem. On the other hand, long fiber pellets can be produced by impregnating a strand made of continuous fibers with a thermoplastic resin and then cutting to a predetermined length. By injection molding the long fiber pellets, An injection molded product having a long fiber length can be produced.

  According to Patent Document 1, it is possible to obtain an injection-molded product having excellent rigidity and impact resistance characteristics by using a long-fiber pellet made of reinforced fiber and propylene resin and having a uniform fiber length of 2 to 200 mm. it can. However, since the long fiber pellets are inferior in productivity as compared with the short fiber pellets produced by a normal extruder, there is a problem that the price of the pellets is high. In addition, even if long fiber pellets are used, if the adhesion between the fiber and the thermoplastic resin is not good enough, the desired reinforcing effect cannot be expressed. Etc. were required.

A typical use example of the electrical and electronic member is a tray for storing and transferring a semiconductor integrated circuit device, for example. This tray for a semiconductor integrated circuit device is light in weight for transport, needs to have impact resistance and high strength in order to withstand repeated use, and in order to protect the semiconductor integrated circuit from damage due to electrostatic discharge, There is a need for conductivity. For this reason, conductive fillers such as metal powder, metal fibers, carbon black, and carbon fibers are provided for the purpose of imparting conductivity to thermoplastic resins such as polypropylene resins and polyphenylene ether resins that constitute trays for semiconductor integrated circuit devices. Is used. However, since metal powder and metal fiber have a large specific gravity and a high weight of a molded product, they are not suitably used for a transfer tray. On the other hand, carbon black is lightweight and excellent in electrical conductivity. However, the semiconductor integrated circuit device is rubbed in contact with the tray during transportation, and the carbon black is likely to fall off the tray, contaminating the semiconductor integrated circuit device. In addition, carbon black has a very small reinforcing effect, has almost no improvement in bending strength and bending elastic modulus required for a tray, and has a problem that impact resistance characteristics are remarkably deteriorated with the addition amount. For this reason, the use of carbon fibers that are difficult to fall off and have a high reinforcing effect has been studied. However, carbon fibers are expensive, and there are problems such as an increase in manufacturing cost of the tray and a tendency for the tray to warp. According to Patent Document 2, impact resistance, conductivity, and warpage can be improved by appropriately adjusting the fiber length and the amount of carbon fiber. However, the target value of surface resistance, which is an index of conductivity, is relatively high at 10 ¹² Ω, and it cannot be said that sufficient conductivity is secured as a tray for a semiconductor integrated circuit device.
JP 2002-226605 A JP 2001-59056 A

  In view of the background of such conventional technology, the present invention is a pellet material for injection molding that exhibits excellent mechanical properties and conductive properties, that is, a high reinforcing effect, light weight and conductivity imparting effect, and excellent productivity. An object of the present invention is to provide a pellet material for injection molding capable of suppressing the molding cost and a method for producing the same.

The present invention employs the following means in order to solve such problems. That is, the pellet material for injection molding according to the present invention has a carbon fiber reinforced plastic material and a thermoplastic resin composed of carbon fibers and a thermosetting resin as essential materials, and the length L of the carbon fiber reinforced plastic material. There Ri der least 15mm below 1 mm, the volume content of carbon fibers contained in the carbon fiber reinforced plastic material is characterized in der Rukoto less 40 vol% or more 70 vol%.

Moreover, the manufacturing method of the pellet material for injection molding of the present invention is such that a punching screen having a punching diameter of 3 mm or more and 15 mm or less is attached to a carbon fiber reinforced plastic composed of continuous carbon fiber and thermosetting resin. After pulverization with the pulverizer, the screen is screened with a screen mesh machine with a screen mesh having an opening of 1 mm or more and 10 mm or less, and the carbon fiber reinforced plastic material and the thermoplastic resin obtained through the screen mesh are passed through. It is characterized by mixing and extruding with an extruder.

  ADVANTAGE OF THE INVENTION According to this invention, the pellet material for injection molding which is excellent in productivity, can suppress shaping | molding cost, and has a high effect of a reinforcement effect, weight reduction, and electroconductivity provision can be provided. In particular, according to the present invention, the injection molding can be suitably used for a resin case of a member for an automobile that requires high mechanical properties, a tray for a semiconductor integrated circuit of an electric and electronic member that requires conductive properties, and the like. A pellet material can be provided.

  The present invention has been intensively studied on the above-mentioned problem, that is, an injection molding pellet material that exhibits excellent mechanical properties and conductive properties, and is controlled only to those having a specific length as such a pellet material. When injection molding was performed using a material and a thermoplastic resin, it was determined that this problem could be solved all at once.

  The pellet material for injection molding of the present invention is characterized in that it is composed of carbon fiber reinforced plastic material composed of carbon fiber and thermosetting resin and thermoplastic resin as essential materials.

  Usually, when carbon fibers cut into long fibers and a thermoplastic resin are kneaded, the carbon fibers are entangled with each other, and it is difficult to produce a pellet material excellent in dispersibility. Further, if the kneading time is increased in order to improve dispersibility, the carbon fibers put in the long fibers are cut by the kneading and eventually become short fibers, so that a sufficient reinforcing effect cannot be exhibited. Since it becomes a pellet material, it is not preferable.

  On the other hand, the pellet material for injection molding of the present invention is composed of carbon fiber reinforced plastic in which carbon fiber bundles are bonded by a thermosetting resin, so that the fiber density can be increased and put into a kneader. And since it is a form of a carbon fiber reinforced plastic, it can be injection-molded without entanglement of fibers. Moreover, the pellet material for injection molding of the present invention is characterized in that the length L of the carbon fiber reinforced plastic material is 1 mm or more and 15 mm or less.

  Here, the length L of the carbon fiber reinforced plastic material is a rectangular long side having a minimum area that can cover the entire area of the carbon fiber reinforced plastic material. FIG. 1 shows the definition of the length L of the carbon fiber reinforced plastic material 1. The long side L of the rectangle 2 having the minimum area covering the area of the carbon fiber reinforced plastic material 1 is defined as the length of the carbon fiber reinforced plastic material.

  By making the length L of the carbon fiber reinforced plastic material within the above specific range, kneading with a thermoplastic resin and extrusion molding can be improved, so that a pellet material for injection molding is produced with high productivity. At the same time, the balance of the fiber lengths of the carbon fibers, which are reinforcing fibers, is good and the reinforcing effect can be increased, so that the injection molded product can be made to have high rigidity and high strength.

  Moreover, since carbon fiber is excellent in electrical conductivity, it is possible not only to use it as a reinforcing material but also to impart electromagnetic wave shielding characteristics and electrostatic elimination characteristics by imparting electrical conductivity to injection molded products. . In this way, in order to add conductivity to an injection molded product by adding a conductive material and to provide electromagnetic wave shielding characteristics and electrostatic elimination characteristics, the conductive material has a conductive path in the injection molded product. Need to form. Therefore, by setting the length L of the carbon fiber reinforced plastic material to the above specific range, carbon fibers having a specific fiber length can be blended into an injection molded product, so that conductive characteristics can be efficiently imparted, That is, electromagnetic wave shielding characteristics or electrostatic elimination characteristics can be imparted. When the length L of such a carbon fiber reinforced plastic material is shorter than 1 mm, not only the reinforcing effect is small, but the carbon fiber reinforced plastic material tends to be bulky and tend to deteriorate kneading and extrudability. Therefore, it is not preferable. On the other hand, if the length is longer than 15 mm, the carbon fiber reinforced plastic material is too large, so that the time for kneading and extrusion molding becomes long, or the nozzle of the extrusion molder tends to clog at the time of extrusion molding, and the extrusion moldability tends to deteriorate. Comes out. For this reason, the length L of the carbon fiber reinforced plastic material is more preferably 1 mm or more and 10 mm or less.

  The carbon fiber reinforced plastic material constituting the pellet material for injection molding of the present invention is preferably composed of continuous fibers. The direction of the longest length L of the carbon fiber reinforced plastic material does not necessarily coincide with the orientation direction of the carbon fiber, but the carbon fiber reinforced plastic material as a raw material is composed of continuous fibers, and the carbon fiber plastic material When the carbon fiber reinforced plastic material used in the pellet material for injection molding according to the present invention is manufactured by pulverizing the carbon fiber, the longest direction of the carbon fiber reinforced plastic material is likely to coincide with the fiber orientation direction, and the carbon fiber The longest length L of the reinforced plastic material is preferable because it becomes the fiber length of the carbon fiber constituting the carbon fiber reinforced plastic material itself or an index thereof.

  The carbon fiber reinforced plastic used as the raw material of the carbon fiber reinforced plastic material of the present invention may be one using discontinuous fibers such as SMC (Sheet Molding Compound) material or BMC (Bulk Molding Compound) material. .

  The production method of the carbon fiber reinforced plastic may be any production method conventionally used. For example, the carbon fiber reinforced plastic of the present invention may be produced by autoclave molding or press molding after laminating a prepreg in which a carbon fiber is pre-impregnated with a matrix resin in a predetermined laminating configuration. Moreover, it is also possible to use what was manufactured by the filament winding shaping | molding which winds and shape | molds the carbon fiber which adhered matrix resin to a mandrel. Furthermore, it is also possible to use a resin produced by resin transfer molding in which a reinforcing fiber base material such as a woven fabric made of carbon fiber is laminated in a predetermined laminated structure, and then a matrix resin is injected into the reinforcing fiber base material and then molded. It is.

  Further, the carbon fiber reinforced plastic material used in the present invention can be used after pulverizing the carbon fiber reinforced plastic discarded after the end of its product life.

  In addition, since the pellet material for injection molding of the present invention is manufactured by means of pulverizing the carbon fiber plastic material, it can be used by pulverizing the used carbon fiber reinforced plastic. There is an advantage that an environment-friendly pellet material for injection molding can be manufactured.

  The thermosetting resin used for the carbon fiber reinforced plastic material constituting the pellet material for injection molding of the present invention is preferably an epoxy resin. Since the epoxy resin has good adhesiveness, it is preferable that the carbon fiber bundle is coated with the epoxy resin because the effect of improving the adhesion between the carbon fiber reinforced plastic material and the thermoplastic resin is obtained. In addition, when the carbon fiber reinforced plastic material is pulverized in each step of kneading, extrusion, and injection molding, a part of the carbon fiber reinforced plastic material is blended in the thermoplastic resin in the form of a fibrous material. Also, the surface of the carbon fibrous material is preferably epoxy-modified, which is considered to improve the adhesion to the thermoplastic resin.

The carbon fiber volume content of such a carbon fiber reinforced plastic material needs to be in the range of 40 vol% or more and 70 vol% or less. That is, when the volume content is less than 40 vol%, the carbon fiber content is too small. Therefore, in the pellet material for injection molding using such a carbon fiber reinforced plastic material, a sufficient reinforcing effect and conductivity improving effect are obtained. Cannot be expressed. On the other hand, if the content is higher than 70 vol%, the carbon fiber content is too high. Therefore, in the pellet material for injection molding using such a carbon fiber reinforced plastic material, the carbon fiber reinforced plastic material itself is in the form of a fibrous material. As a result, the carbon fiber reinforced plastic material becomes bulky at the time of kneading and extrusion molding, resulting in a deterioration in moldability. From the viewpoint of moldability reinforcing effect, said volume content, good preferable if less than 50 vol% 60 vol%.

  Moreover, it is preferable that the elasticity modulus of the carbon fiber of this carbon fiber reinforced plastic material is 200 GPa or more. That is, when the elastic modulus is less than 200 GPa, the elastic modulus of the carbon fiber is too low, and the injection molding pellet material using the injection molding pellet material using the carbon fiber reinforced plastic material is sufficient. In some cases, the reinforcing effect cannot be expressed. In particular, in the technical field related to injection-molded articles using reinforcing fibers having a fiber length used in the present invention, one of the important roles is to improve the rigidity of the injection-molded article with reinforcing fibers. If it is less than 200 GPa, the effect of improving the rigidity of the obtained injection-molded product tends to be small.

  Examples of the thermoplastic resin used in the present invention include polyester resins, polyphenylene ether resins, PPS resins, polypropylene resins, ABS resins, and polyamide resins. Among these, polyester resins, polyphenylene ether resins, and PPS resins are excellent in heat resistance characteristics and mechanical characteristics, and thus can be suitably used for trays for semiconductor integrated circuits that require high-temperature heat history.

  In addition, since the polypropylene resin has a small specific gravity and an excellent balance of mechanical properties, it can be suitably used for a vehicle member. Furthermore, ABS-based resins and polyamide-based resins are excellent in moldability, mechanical properties, particularly impact resistance properties, and can be suitably used for personal computer housings. However, it is not limited to these thermoplastic resins, and other resins can be used as necessary.

  In the method for producing a pellet material for injection molding according to the present invention, a carbon fiber reinforced plastic material composed of carbon fibers which are continuous fibers and a thermosetting resin is pulverized with a punching screen having a punching diameter of 3 mm or more and 15 mm or less. After pulverizing with a machine, the screen is screened with a screen machine to which a screen mesh having an opening of 1 mm or more and 10 mm or less is attached, and the carbon fiber reinforced plastic material and thermoplastic resin obtained through the screen mesh are extruded. And a means for producing an injection molding pellet material by mixing and extruding.

  The carbon fiber reinforced plastic material having a length L of 1 mm or more and 15 mm or less used in the present invention may be prepared by any method, but the carbon fiber reinforced plastic material is a material having high strength and high elastic modulus. Therefore, there is a concern that processing by cutting or the like is extremely difficult. On the other hand, not only carbon fiber reinforced plastic materials but also fiber reinforced plastics generally have low impact characteristics, and therefore can be pulverized relatively easily by a pulverizer. Therefore, the carbon fiber reinforced plastic material used in the present invention can be efficiently produced by pulverizing the raw material carbon fiber reinforced plastic with a pulverizer. In particular, a shearing type pulverizer is preferably used because it can be efficiently pulverized.

  The length L of the carbon fiber reinforced plastic material used in the present invention is not less than 1 mm and not more than 15 mm. In order to adjust the carbon fiber reinforced plastic as a raw material to a length L in this range, A punching screen of 3 mm or more and 15 mm or less is attached. A carbon fiber reinforced plastic material that can be used in the present invention can be obtained by pulverizing the raw material carbon fiber reinforced plastic until it passes through the hole of the punching screen. Furthermore, it is possible to obtain a carbon fiber reinforced plastic material having a desired length L by sieving the carbon fiber reinforced plastic material with a sieving machine to which a screen mesh having an opening of 1 mm or more and 10 mm or less is attached.

  That is, in order to improve the kneading and extrusion moldability, when it is desired to obtain a carbon fiber reinforced plastic material having a relatively short length, it is selectively obtained by using a screen mesh having an opening of 1 mm or more and 5 mm or less. be able to. On the other hand, in order to obtain a carbon fiber reinforced plastic material having a relatively long length in anticipation of a reinforcing effect and an effect of imparting conductivity, a screen mesh having an opening of 5 mm or more and 10 mm or less can be selectively used. Can get to. Thus, the pellet material for injection molding of this invention can be manufactured by knead | mixing and extruding the obtained carbon fiber reinforced plastic material and thermoplastic resin with an extruder.

  Furthermore, the temperature of the cylinder of the extruder is preferably lower than the thermal decomposition temperature of the thermosetting resin constituting the carbon fiber reinforced plastic material. The thermal decomposition temperature means a temperature when a weight loss is 1% or a temperature when a weight loss is 5% when the weight loss is measured by thermogravimetric analysis. More preferably, the temperature is 1% weight loss. When the thermosetting resin is exposed to a temperature equal to or higher than the thermal decomposition temperature, it is gasified to cause weight loss. When the temperature at the time of kneading and extrusion molding is higher than the thermal decomposition temperature of the thermosetting resin constituting the carbon fiber reinforced plastic material, the thermosetting resin is pyrolyzed to generate gas. There is a possibility that bubbles such as voids may be contained in the pellet for use, and the residue of the thermosetting resin generated by thermal decomposition is contained in the pellet material for injection molding, which is not preferable. Of course, for the same reason, the cylinder temperature of the injection molding machine in the case of injection molding using the pellet material for injection molding may be lower than the thermal decomposition temperature of the thermosetting resin. preferable. By making the temperature at the time of kneading, extrusion and injection molding lower than the thermal decomposition temperature of the thermosetting resin, it is possible to produce an injection molding pellet material and an injection molded product with few defects such as voids.

  Hereinafter, the present invention will be described in more detail with reference to examples.

  The manufacturing method of the carbon fiber reinforced plastic material which is a raw material of the pellet material for injection molding used for an Example is demonstrated.

  The carbon fiber reinforced plastic as a raw material for the carbon fiber reinforced plastic material is composed of carbon fiber T700S manufactured by Toray Industries, Inc. and bisphenol A type epoxy resin. That is, after impregnating bisphenol A type epoxy resin with carbon fiber T700S and winding it around a mandrel with an outer diameter of 70 mm to a thickness of 7 mm, the mandrel is heated at a temperature of 180 ° C. for 6 hours while rotating the epoxy resin. Was cured. After the epoxy resin was cured, a mandrel was pulled out to prepare a cylindrical carbon fiber reinforced plastic.

  This carbon fiber T700S has a tensile modulus of 230 GPa, and the carbon fiber content of the carbon fiber reinforced plastic is adjusted to 60 vol%. The thermal decomposition temperature of the epoxy resin is 320 ° C. with 5% weight loss.

  This carbon fiber reinforced plastic is pulverized using a V480 type uniaxial shearing type pulverizer manufactured by Horai Co., Ltd., and then screened by a vibrating screener 1003c-s manufactured by Dalton Co., Ltd. to which a three-stage screen mesh can be attached. Thus, a carbon fiber reinforced plastic material used as a raw material for the injection molding pellet material was manufactured.

  By attaching a punching screen with a punching diameter of 5 mm to the pulverizer, attaching a screen mesh with openings of 10 mm, 5.6 mm, and 1.0 mm from above to the vibrating sieve, crushing and sieving the carbon fiber reinforced plastic, Carbon fiber reinforced plastic material was manufactured. The carbon fiber reinforced plastic material passed through the 1.0 mm screen mesh is crushed piece A, the carbon fiber reinforced plastic material passed through the 5.6 mm screen mesh and sieved with the 1.0 mm screen mesh is crushed piece B, A carbon fiber reinforced plastic material that has passed through a 10 mm screen mesh and screened with a 5.6 mm screen mesh is referred to as a crushed piece C.

  The length L of 50 crushed pieces A was measured, and the average value was obtained. As a result, it was 3.4 mm.

  The length L of 50 crushed pieces B was measured and the average value was obtained. As a result, it was 9.9 mm.

  The length L of 50 crushed pieces C was measured, and the average value was obtained. As a result, it was 21.0 mm.

Example 1
The crushed pieces A were blended with polyphenylene ether resin so as to be blended at 5 wt%, 10 wt%, 15 wt%, and 20 wt%, respectively, mixed with a tumbler mixer, and then the cylinder temperature of the twin screw extruder was set at 280 to 300 ° C. The pellet material for injection molding was manufactured by setting to kneading and extrusion molding.

  In the kneading and extruding steps, the pulverized piece A was bulky and difficult to knead, or there was no problem such as clogging of the nozzle of the extruder, and the handleability was very good.

  After the pellet material for injection molding is dried at 100 ° C. for 5 hours, the cylinder temperature of the injection molding machine is set to 310 ° C., the mold temperature is set to 140 ° C., and each test of tension and bending is performed based on JIS K 7139 A type. A piece was molded. The tensile test was measured based on JIS K 7162, and the bending test was measured based on JIS K 7171.

  Similarly, a plate-shaped test piece for measuring surface resistance of 120 × 120 × 2 mm was formed. A silver paste is applied to an area of 5 × 10 mm so as to have an interval of 1 cm at 9 locations on one side of the molded product, and an applied voltage of 250 V is applied between the electrodes, and 9 locations in the test piece are applied. The resistance value was measured and the value was defined as the surface resistance.

  As a result, both the tensile modulus and tensile strength improved with the blending amount of the crushed piece A, and improved to 2.0 times and 1.6 times compared to the blank without the crushed piece at the blending amount of 20 wt%, respectively. I found out that

  Further, both the flexural modulus and the bending strength are improved with the blending amount of the crushed pieces A, and are improved to 3.0 times and 1.4 times as compared with the blank in which the crushed pieces are not blended at the blending amount of 20 wt%, respectively. I understood it.

The surface resistance value decreased with the blending amount of the crushed pieces A, and was 4 × 10 ⁴ Ω at the blending amount of 20 wt%.
Moreover, the injection molded board which mix | blended 5-20 wt% of the grinding | pulverization pieces A did not have defects, such as a void, and the surface quality was favorable.

(Example 2)
A pellet material for injection molding was produced in the same manner as in Example 1 except that the crushed piece B was used instead of the crushed piece A.

  In the kneading and extruding steps, the pulverized piece A was bulky and difficult to knead, or there was no problem such as clogging of the nozzle of the extruder, and the handleability was very good.

  Further, in the same manner as in Example 1, test pieces for tension, bending, and surface resistance were formed, and measurement was performed.

  As a result, both the tensile elastic modulus and the tensile strength are improved with the blending amount of the crushed piece B. When the blending amount is 20 wt%, the tensile modulus and tensile strength are improved to 2.2 times and 1.7 times, respectively, compared with the blank in which the crushed piece is not blended. I found out that

  Further, both the flexural modulus and the bending strength are improved with the blending amount of the crushed pieces B. When the blending amount is 20 wt%, the bending elastic modulus and the bending strength are improved to 3.5 times and 1.7 times, respectively, compared with the blank in which the crushed pieces are not blended. I understood it.

The surface resistance value decreased with the blending amount of the crushed pieces B, and was 3.5 × 10 ⁴ Ω at the blending amount of 20 wt%.
In addition, the injection molded plate containing 5 to 20 wt% of the crushed pieces B did not show defects such as voids, and the surface quality was good.

(Comparative Example 1)
A pellet material for injection molding was produced in the same manner as in Example 1 except that the crushed piece C was used instead of the crushed piece A.

  In the kneading and extruding steps, the pulverized piece C has a length L of the carbon fiber reinforced plastic material that is too large, which causes problems such as clogging the nozzle of the extruder, and it is difficult to produce a pellet material. Each test piece could not be prepared.

This figure is a schematic view showing an example of the carbon fiber reinforced plastic material of the present invention.

Explanation of symbols

1: Carbon fiber reinforced plastic material 2: Rectangle with minimum area covering the area of carbon fiber reinforced plastic material

Claims (7)

The carbon fiber reinforced plastic material composed of carbon fiber and a thermosetting resin and a thermoplastic resin are essential materials, and the length L of the carbon fiber reinforced plastic material is 1 mm or more and 15 mm or less, and the carbon fiber reinforced A pellet material for injection molding, wherein a volume content of carbon fibers contained in a plastic material is 40 vol% or more and 70 vol% or less. The pellet material for injection molding according to claim 1, wherein a length L of the carbon fiber reinforced plastic material is 1 mm or more and 10 mm or less. The pellet material for injection molding according to claim 1 or 2, wherein the thermosetting resin constituting the carbon fiber reinforced plastic material is an epoxy resin. The pellet material for injection molding according to any one of claims 1 to 3, wherein an elastic modulus of carbon fibers contained in the carbon fiber reinforced plastic material is 200 GPa or more. 5. The thermoplastic resin is at least one thermoplastic resin selected from the group consisting of polyester resins, polyphenylene ether resins, polystyrene resins, PPS resins, ABS resins, and polyamide resins. The pellet material for injection molding according to any one of the above. Carbon fiber reinforced plastic composed of continuous carbon fiber and thermosetting resin is pulverized by a pulverizer equipped with a punching screen having a punching diameter of 3 mm or more and 15 mm or less, and then the opening is 1 mm or more and 6 mm or less. The carbon fiber reinforced plastic material obtained by passing through the screen mesh and the thermoplastic resin are mixed and extruded by an extruder. The manufacturing method of the pellet material for injection molding in any one of 1-5. The temperature of the cylinder of the said extruder is a temperature lower than the thermal decomposition temperature of the thermosetting resin which comprises the pellet material for injection molding, The manufacturing method of the pellet material for injection molding of Claim 6 characterized by the above-mentioned. .

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