JP2013245328A - Fiber-reinforced resin pellet, method for producing the same, and fiber-reinforced molded resin article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fiber-reinforced resin pellet having high affinity of natural vegetable fiber and thermoplastic synthetic fiber and good moldability, a method for producing the pellet, and a fiber-reinforced molded resin article.SOLUTION: There is provided a fiber-reinforced resin pellet containing natural vegetable fibers and thermoplastic synthetic fibers, wherein the natural vegetable fiber is a reinforcing fiber, the thermoplastic synthetic fiber is melted to form a matrix resin, and the fiber-reinforced resin pellet has a hexahedral form and has at least four cut faces. The fiber-reinforced resin pellet can be produced by pressing a fiber aggregate containing the natural vegetable fibers and the thermoplastic synthetic fibers at or above the melting point of the resin constituting the thermoplastic synthetic fiber to form a fiber-reinforced resin sheet, and cutting the resin sheet in longitudinal and lateral directions. The fiber-reinforced molded resin article can be produced by molding a resin material containing the fiber-reinforced resin pellet into a desired form.

Description

The present invention relates to a fiber reinforced resin pellet containing natural plant fibers, a production method thereof, and a fiber reinforced resin molded article.

Plastic is used for the interior of automobiles, airplanes, vehicles, etc., and is lighter than metal. Since plastic alone is insufficient in strength, glass short fibers (cut to a certain length) are mixed in the plastic. However, when discarded, if it is burned in an incinerator, the plastic decomposes into CO ₂ and water, but the glass melts and hardens and adheres to the inside of the incinerator. As a result, there is a concern that the life of the incinerator is significantly reduced. Carbon fiber is known as a material having high strength such as glass fiber, but it is expensive and its use is limited.

  Thus, in recent years, there has been an increasing social interest in fiber reinforced thermoplastic resin molded articles (FRTP) made of natural plant fibers. This is recyclable, and can be used repeatedly as material recycling, no toxic gas is generated during combustion as thermal recycling, and it is possible to reduce the weight of moving objects due to energy problems. The natural plant fiber absorbs carbon dioxide in its interior during photosynthesis, and the carbon dioxide that is emitted even when burned is the same as the original, so there are advantages such as not causing environmental problems.

  Patent Documents 1 and 2 propose fiber reinforced resins using natural plant fibers as reinforcing fibers. Patent Document 1 describes that short fibers of hemp fibers are processed into nonwoven fabrics, woven fabrics, and knitted fabrics to form fiber reinforced resins. Patent Document 2 describes processing of short fibers of kenaf fibers into nonwoven fabrics and woven fabrics. It is described that a fiber reinforced resin is used.

  Further, the present applicant has proposed a fiber reinforced resin molded body in which natural plant fiber yarn such as hemp and a synthetic resin film are fused and integrated in Patent Document 3, and in Patent Document 4 around the natural plant fiber yarn such as hemp. It was proposed that the covering yarn wound so as to cover the synthetic resin fiber yarn be a composite yarn for a fiber reinforced resin molded article.

  However, the inventions described in Patent Documents 1 and 2 are processed into non-woven fabrics, woven fabrics, and knitted fabrics using hemp fibers and kenaf short fibers and melt-mixed with the resin or impregnated into fiber reinforced resin (FRP). For this reason, there is a problem that the resin does not easily penetrate into the fiber, a large-scale apparatus is required, and molding is not easy. In particular, natural plant fibers have a lower decomposition temperature than glass fibers and carbon fibers, and cannot be heated to a viscosity that facilitates the penetration of thermoplastic resins as matrix resins. Met.

  Further, in the invention described in Patent Document 3, it is difficult for the applicant to melt the synthetic resin film and uniformly impregnate the natural plant fiber yarn. The invention described in Patent Document 4 is a covering yarn. In addition, it has been found that the synthetic resin film used for the cover ring is easily caught on a pin tenter and the like, resulting in a problem of lowering the productivity.

JP 2004-143401 A JP 2004-149930 A JP 2007-138361 A JP 2008-240193 A

  In order to solve the above problems, the present invention provides a fiber reinforced resin pellet having good integrity between natural plant fibers and thermoplastic synthetic fibers and good moldability, a method for producing the same, and a fiber reinforced resin molded article.

  The fiber-reinforced resin pellet of the present invention is a fiber-reinforced resin pellet containing natural plant fibers and thermoplastic synthetic fibers, wherein the natural plant fibers are reinforcing fibers, and the thermoplastic synthetic fibers are melted into a matrix resin, The fiber-reinforced resin pellet is a hexahedron and has at least four cut surfaces.

  The method for producing fiber-reinforced resin pellets of the present invention is a fiber-reinforced resin sheet obtained by press-molding a fiber assembly containing natural plant fibers and thermoplastic synthetic fibers at a temperature equal to or higher than the melting point of the thermoplastic synthetic fibers. By cutting the fiber reinforced resin sheet in both the length direction and the width direction, a hexahedral fiber reinforced resin pellet having at least four cut surfaces is obtained.

  The fiber reinforced resin molded article of the present invention is characterized in that a resin material including the above fiber reinforced resin pellets is molded into a predetermined shape.

  The present invention provides a fiber reinforced resin pellet containing natural plant fibers and thermoplastic synthetic fibers, in which natural plant fibers are used as reinforcing fibers, molten thermoplastic synthetic fibers are used as matrix resins, and hexahedral pellets having at least four cut surfaces. By doing so, it is possible to provide a fiber reinforced resin pellet having good integrity between the natural plant fiber and the thermoplastic synthetic fiber and good moldability, and a fiber reinforced resin molded article using the same. In particular, the fiber-reinforced resin pellet of the present invention can be used as a molding raw material for injection molding, extrusion molding, blow molding, and the like, can be molded into a complicated shape, and has excellent moldability. Moreover, since natural plant fiber is used, the environmental problem at the time of disposal can be eliminated. Moreover, this invention can provide the fiber reinforced resin molding which is excellent in rigidity and impact resistance.

1A to 1C are conceptual perspective views showing a method for producing fiber-reinforced resin pellets. 2A to 2D are conceptual perspective views showing a method for manufacturing a fiber-reinforced resin sheet. FIG. 3 is a conceptual perspective view of a multi-axis inserted warp knitted fabric.

  In the fiber reinforced resin pellets of the present invention, natural plant fibers are reinforcing fibers, and thermoplastic synthetic fibers are melted into a matrix resin, so that fiber reinforced with good integrity between natural plant fibers and thermoplastic synthetic fibers Resin pellets are obtained.

  Although it does not specifically limit as a natural plant fiber which can be used by this invention, For example, hemp fibers, such as cotton fiber, a linen, a flux, a ramie, a kenaf, and a jute, bamboo fiber, a kapok etc. are mentioned. Cotton is preferred because it is mass-produced and can be easily obtained in a homogeneous manner. Hemp fibers such as linen or ramie are also preferred. This is because hemp fibers are suitable as reinforcing fibers because of their excellent mechanical properties, and the raw material supply is also stable. The hemp fiber is preferably dried, but can also be used in a state having an equilibrium moisture content without being dried. This is because the strength can be kept high with an equilibrium moisture content.

  The resin constituting the thermoplastic synthetic fiber that can be used in the present invention is preferably a resin that is usually used as a matrix resin for FRP and has a melting point lower than the decomposition temperature of natural plant fibers. For example, a resin having a melting point of 90 to 200 ° C. is preferable. In particular, for example, when cotton (cotton) or hemp fiber is used as the natural plant fiber, a resin having a melting point of 90 to 200 ° C. is preferable. Examples of such a resin include polyolefin, polyamide, copolymer polyester, copolymer polyamide, polyvinyl chloride, copolymer polyacetal, polylactic acid, and polybutyl succinate. Examples of the polyolefin include polypropylene (PP), polyethylene (PE), and copolymers thereof.

  The blending ratio of the natural plant fiber and the thermoplastic synthetic fiber in the fiber reinforced resin pellet of the present invention is preferably in the range of natural plant fiber: thermoplastic synthetic fiber = 80: 20 to 20:80 by mass ratio. If it is this range, the composite integration of natural vegetable fiber and the resin which the thermoplastic synthetic fiber fuse | melted can be performed efficiently.

  The fiber reinforced resin pellet of the present invention is a hexahedron and has at least four cut surfaces. The fiber reinforced resin pellet may have five cut surfaces, and all the surfaces of the hexahedron may be cut surfaces. When such a fiber reinforced resin pellet is used as a molding raw material, it can be molded into a fiber reinforced resin molded body having a complicated shape, and is excellent in moldability. The size of the fiber reinforced resin pellet is not particularly limited, and can be appropriately selected according to the purpose and application. From the viewpoint of physical properties of the molded body and workability during molding, the fiber reinforced resin pellets have a length of 1 to 20 mm, a width of 1 to 20 mm, and a thickness of 0.1 to 10 mm, more preferably a length of 1.5. It is preferably 10 mm, a width of 1.5 to 10 mm, and a thickness of 0.5 to 8 mm, more preferably a cube.

  Hereinafter, the manufacturing method of the fiber reinforced resin pellet of this invention is demonstrated using drawing etc. FIG.

  Although the said fiber reinforced resin pellet is not specifically limited, It is preferable to obtain by making into a sheet | seat the fiber assembly containing a natural plant fiber and a thermoplastic synthetic fiber, and cut | disconnecting this sheet | seat to both the length direction and the width direction.

  1A to 1C are conceptual perspective views showing a method for producing fiber-reinforced resin pellets. As shown in FIGS. 1A to 1C, first, the fiber assembly 1 is made into a sheet to form a strong fiber resin sheet 2. Next, the fiber reinforced resin sheet 2 is cut in both the length direction and the width direction to obtain fiber reinforced resin pellets 3 having a predetermined size.

(1) Fiber aggregate The fiber aggregate is not particularly limited as long as it contains natural plant fibers and thermoplastic synthetic fibers. For example, any fiber wrap, sliver, nonwoven fabric, woven fabric, knitted fabric, etc. May be used. From the viewpoint of low cost, it is more preferable to use a fiber assembly in a wrap and / or sliver form.

  In the fiber assembly, the blending ratio of the natural plant fiber and the thermoplastic synthetic fiber is preferably in the range of natural plant fiber: thermoplastic synthetic fiber = 80: 20 to 20:80 in terms of mass ratio. If it is this range, the composite integration of natural vegetable fiber and the resin which the thermoplastic synthetic fiber fuse | melted can be performed efficiently.

  The preferred fiber length of the natural plant fiber is 10 to 400 mm. Specifically, the fiber length of cotton fiber (cotton) is preferably 10 to 50 mm, and the hemp fiber (ramie) is preferably fiber length of 20 to 300 mm. Moreover, the preferable fiber diameter of a natural plant fiber is 10-100 micrometers. The fiber diameter of the cotton fiber (cotton) is preferably 10 to 30 μm, and the fiber diameter of the hemp fiber (ramie) is preferably 20 to 100 μm. If the fiber length and fiber diameter are in this range, it is easy to handle as a fiber for FRP, and blending and blending with a thermoplastic synthetic fiber and the like are facilitated.

  It is preferable to use a thermoplastic synthetic fiber having a fineness and a fiber length in the same range as that of natural plant fiber. In particular, the difference in fiber length between the natural fiber and the thermoplastic synthetic resin is preferably within a range of about ± 20 mm. Blending and cotton blending of natural fibers and thermoplastic synthetic resins are facilitated. The thermoplastic synthetic fiber preferably has a single fiber fineness of 0.5 to 10 dtex, more preferably 1 to 5 dtex.

  Although it does not specifically limit as a wrap, For example, the sheet-like wrap by which the natural vegetable fiber and thermoplastic synthetic fiber after the blended cotton process were mixed can be used. Although it does not specifically limit as a sliver, For example, the sliver of a natural plant fiber and the sliver of a thermoplastic synthetic fiber can be arranged in parallel and used in one direction. A plurality of slivers in which natural plant fibers and thermoplastic synthetic fibers are mixed can also be used. In addition, the sliver in which the natural plant fiber and the thermoplastic synthetic fiber are mixed can be obtained by mixing each sliver in a drawing step or the like.

  As the fiber assembly, a laminate in which wraps, slivers, nonwoven fabrics, woven fabrics, knitted fabrics and the like are laminated may be used. For example, as the fiber assembly, a multi-axis inserted warp knitted fabric can be used. FIG. 3 is a conceptual perspective view of a multi-axis inserted warp knitted fabric. As shown in FIG. 3, in the multi-axis inserted warp knitted fabric 20, stitched yarns 21 a to 21 f of natural plant fibers and thermoplastic synthetic fibers respectively arranged in a plurality of directions are hung on a knitting needle 26. The yarns (sewing threads) 27 and 28 are stitched (bundled) in the thickness direction and integrated.

  The fiber assembly may further contain an additive depending on physical properties and applications required for the fiber-reinforced resin formed body. Examples of the additive include flame retardants, pigments, stabilizers, antistatic agents, compatibilizers, and the like, and can be used alone or in combination of two or more as necessary.

(2) Sheeting The fiber assembly can be formed into a sheet by a conventionally known molding method, and examples thereof include a hot stamping method, a prepreg molding method, and a press molding method.

  2A to 2D are conceptual perspective views showing a process of manufacturing a fiber-reinforced resin sheet by forming a fiber assembly into a sheet. First, as shown in FIG. 2A, the fiber assembly 1 is arranged in a sheet shape on the lower mold 11, and the upper mold 12 is arranged thereon. Next, as shown in FIG. 2B, the sheet-like product of the fiber assembly 1 is subjected to a heat press machine and heated and pressed at a temperature equal to or higher than the melting point of the thermoplastic synthetic fiber, and then cooled as shown in FIG. 2C. By moving to a press machine and performing cooling press, the thermoplastic synthetic fiber is melted and the fiber assembly 1 is melted and integrated. Thereafter, as shown in FIG. 2D, the fiber reinforced resin sheet 2 is obtained by demolding. The thickness of the fiber reinforced resin sheet 2 can be adjusted by disposing a clearance spacer between the lower mold 11 and the upper mold 12. In press molding, the temperature of the hot press is preferably not lower than the melting point of the resin constituting the thermoplastic synthetic fiber and not higher than the natural plant fiber decomposition temperature, more preferably 180 to 240 ° C., still more preferably 190 to 230. ° C. In particular, it is preferable to mold at a temperature as high as possible in consideration of the impregnation property of the resin constituting the thermoplastic synthetic fiber into the natural plant fiber in the above temperature range. When hemp fiber is used as the natural plant fiber, a temperature that does not exceed about 200 ° C. is preferable as the molding temperature. In addition, when the resin constituting the thermoplastic synthetic fiber has a lower melting point than the decomposition temperature of the hemp fiber, such as a melting point of about 120 ° C., it may be molded at a temperature about 0 ° C. to 50 ° C. higher than the melting point temperature. Good. Further, the molding pressure at the time of hot pressing is 0.1 to 20 MPa, the molding time is preferably 0.5 to 30 minutes, the molding pressure is 0.5 to 8 MPa, and the molding time is 2 to 15 minutes. More preferred. It does not specifically limit as cooling press conditions, For example, it can be set as the temperature of 15-80 degreeC, the molding pressure of 0.1-20 MPa, and the molding time of 15-600 seconds. Here, the method of forming the fiber assembly into a sheet by the batch press method has been described, but the fiber assembly may be formed into a sheet by the double belt press method.

(3) Pelletization By cutting the fiber reinforced resin sheet obtained above in both the length direction and the width direction, hexahedral fiber reinforced resin pellets having at least four cut surfaces are obtained. Furthermore, by slicing the fiber reinforced resin sheet also in the thickness direction, hexahedral fiber reinforced resin pellets having five cut surfaces or six cut surfaces can be obtained. The cutting method is not particularly limited as long as the fiber-reinforced resin sheet can be cut into a predetermined size. Also, pellets can be obtained by a method of molding with a square pelletizer or the like and cutting the obtained sheet.

  The fiber reinforced resin pellet can be molded into a complicated shape by using it as a molding raw material for injection molding, extrusion molding, blow molding or the like, and has excellent moldability.

  The resin material containing the fiber reinforced resin pellets is molded into a predetermined shape to obtain a fiber reinforced resin molded body. From the viewpoint of the rigidity and impact resistance of the fiber reinforced resin molded product, the content of the natural plant fiber is preferably 10% by mass or more, more preferably 30% by mass or more with respect to 100% by mass of the resin material. Yes, more preferably 40% by mass or more.

  The method for molding the fiber-reinforced resin molded body is not particularly limited, and any molding method such as injection molding, extrusion molding, or blow molding may be used. From the viewpoint of formability and productivity, it is preferable to mold by injection molding. The conditions for injection molding are not particularly limited, and can be set as appropriate according to the physical properties and use of the fiber-reinforced resin molded product. From the viewpoint of the reinforcing effect, the screw temperature (material temperature) is preferably equal to or lower than the decomposition temperature of the natural plant fiber and equal to or higher than the melting point of the resin constituting the thermoplastic synthetic fiber, more preferably 180 to 240 ° C. Yes, more preferably 190-230 ° C. The holding pressure is 0 to 100 MPa, the injection speed is 10 to 100 mm / second, the injection pressure (primary pressure) is preferably 10 to 200 MPa, and more preferably the holding pressure is 20 to 80 MPa. The speed is 20 to 80 mm / second, and the injection pressure (primary pressure) is 60 to 200 MPa.

From the viewpoint of excellent rigidity, the fiber reinforced resin molded product preferably has a tensile modulus measured by a tensile test according to JIS K 7162 (1994) of 2 GPa or more, more preferably 2.5 GPa or more. Yes, the tensile strength is preferably 10 MPa or more, and more preferably 20 MPa or more. From the viewpoint of excellent rigidity, the fiber reinforced resin molded product preferably has a flexural modulus of 1.5 GPa or more, more preferably 2 GPa, as measured by a bending test according to JIS K 7171 (2004). The bending strength is preferably 30 MPa or more, more preferably 35 MPa or more. Further, from the viewpoint of excellent impact resistance, the fiber reinforced resin molded product preferably has a Charpy impact strength measured by a Charpy impact test according to ASTM D 256, preferably 3 kJ / m ² or more, and more preferably. Is 5 kJ / m ² or more.

  The present invention will be specifically described below with reference to examples. In addition, this invention is not limited to the following Example.

Example 1
<Sheet>
Cotton fibers (average fiber diameter 12 μm, average fiber length 28 mm) are used as natural plant fibers, and polypropylene fibers (trade name “PN-17038”, manufactured by Daiwabo Polytech Co., Ltd.), single fiber fineness 1.7 dtex, average as thermoplastic synthetic fibers Fiber length 38 mm) was used. First, 43 cotton fiber slivers (thickness 4.7 g / m) and 43 polypropylene fiber slivers (thickness 4.7 g / m) were aligned to obtain an aggregate 20 cm long and 20 cm wide. . The obtained assembly was press-molded with a single-action compression molding machine ("NF-37 type", manufactured by Shinto Metal Industries Co., Ltd., heating / cooling two-stage type), and was 20 cm long, 20 cm wide, and 2 mm thick. A fiber reinforced resin sheet was obtained. The heating press was performed at 1 MPa for 2 minutes after the assembly was set in a mold at room temperature and the mold temperature was raised to 200 ° C. over 9 minutes. The cooling press was performed at 20 ° C. and 1 MPa for 5 minutes.

<Pelletization>
The fiber reinforced resin sheet obtained above is cut in both the length direction and the width direction using a pelletizer (manufactured by Sanriki Co., Ltd., SGP-450 type), and the length is 3.5 mm, the width is 3.5 mm, A hexahedral fiber reinforced resin pellet having a thickness of 2 mm was obtained.

<Production of molded body>
The fiber reinforced resin pellet obtained above was dried at 80 ° C. for 2 hours. The fiber-reinforced resin pellets after drying were injection-molded with an injection molding machine (manufactured by Toyo Machine Metal Co., Ltd., 80t electric servo injection molding machine, Si-80IV) to prepare a fiber-reinforced resin molded body. Molding conditions were: screw temperature was 200 ° C, 200 ° C, 200 ° C, 200 ° C, 200 ° C in order from the bottom of the hopper, cooling time was 30 seconds, holding pressure time was 10 seconds, holding pressure was 50 MPa, injection The speed was 30 mm / second, the injection pressure (primary pressure) was 180 MPa, and the mold temperature was 40 ° C. In addition, a shaping | molding shape is a test piece shape of each tension test and a bending test (thickness 5mm).

(Example 2)
Using the cotton sliver and polypropylene fiber sliver used in Example 1, the sliver was performed once to obtain a mixed sliver adjusted to a thickness of 4.7 g / m, and then 86 slivers were arranged side by side. In the same manner as in Example 1, fiber reinforced resin pellets and fiber reinforced resin molded bodies were produced.

(Example 3)
Using the cotton sliver and polypropylene fiber sliver used in Example 1, the sliver was performed twice to obtain a mixed sliver adjusted to a thickness of 4.7 g / m, and then 86 such slivers were arranged. In the same manner as in Example 1, fiber reinforced resin pellets and fiber reinforced resin molded bodies were produced.

Example 4
Using the cotton sliver and the polypropylene fiber sliver used in Example 1, the drawing was performed three times to obtain a mixed sliver adjusted to a thickness of 4.7 g / m, and then 86 slivers were arranged. In the same manner as in Example 1, fiber reinforced resin pellets and fiber reinforced resin molded bodies were produced.

(Example 5)
<Sheet>
84 dtex cotton PP blended yarn (50% by weight cotton, 50% by weight PP) was further arranged so that the insertion angle was 90 ° C., the number of insertions was 48 / inch, and the basis weight was 159.0 g / m ² . Further, 84 dtex cotton PP blended yarn (50% by weight cotton, 50% by weight PP) is placed thereon so that the insertion angle is 30 ° C., the number of insertions is 15 / inch, and the basis weight is 159.0 g / m ^2. Arranged one more layer. Furthermore, an 84 dtex cotton PP blended yarn (50% by mass cotton, 50% by mass PP) is inserted at an insertion angle of −30 ° C., the number of insertions is 15 / inch, and the basis weight is 159.0 g / m ^2. Arranged one more layer. Finally, 8.3 dtex polyester yarn is used as a sewing thread, stitched (bundled) in the thickness direction at a number of insertions of 250 / inch, integrated, and multiaxially inserted with a basis weight of 483.8 g / m ² I got knitting.

  A fiber reinforced resin pellet and a fiber reinforced resin molded body were produced in the same manner as in Example 1 except that four multiaxially inserted warp knitted fabrics obtained above were laminated and used.

(Example 6)
Using the cotton sliver and the polypropylene fiber sliver used in Example 1, the sliver was performed three times to obtain a mixed sliver adjusted to a thickness of 5.6 g / m, and then 72 slivers were arranged. In the same manner as in Example 1, fiber reinforced resin pellets and fiber reinforced resin molded bodies were produced.

(Example 7)
Fiber reinforced resin pellets were produced in the same manner as in Example 6. After drying the obtained fiber reinforced resin pellet at 80 ° C. for 2 hours, the fiber reinforced resin pellet and the polypropylene resin for injection molding (trade name “NOVATEC”, MA1B, MFR 21 g / 10 min, manufactured by Nippon Polypro Co., Ltd.) A fiber reinforced resin molded article was produced in the same manner as in Example 6 except that the resin material mixed so that the ratio was 80:20 was used.

(Example 8)
Other than using a resin material in which fiber reinforced resin pellets and polypropylene resin for injection molding (trade name “NOVATEC”, MA1B, MFR 21 g / 10 min, manufactured by Nippon Polypro Co., Ltd.) are mixed so that the mass ratio is 60:40 Produced a fiber-reinforced resin molded body in the same manner as in Example 7.

Example 9
Except for using a resin material in which fiber reinforced resin pellets and polypropylene resin for injection molding (made by Nippon Polypro Co., Ltd., trade name “NOVATEC”, MA1B, MFR 21 g / 10 min) are mixed so that the mass ratio is 40:60. Produced a fiber-reinforced resin molded body in the same manner as in Example 7.

(Example 10)
Other than using a resin material in which fiber reinforced resin pellets and polypropylene resin for injection molding (trade name “NOVATEC”, MA1B, MFR 21 g / 10 min, manufactured by Nippon Polypro Co., Ltd.) are mixed so that the mass ratio is 20:80. Produced a fiber-reinforced resin molded body in the same manner as in Example 7.

(Comparative Example 1)
A fiber reinforced resin molded article was produced in the same manner as in Example 1 except that polypropylene resin for injection molding (trade name “NOVATEC”, MA1B, MFR 21 g / 10 min, manufactured by Nippon Polypro Co., Ltd.) was used.

  Specific gravity of the fiber reinforced resin pellets obtained in Examples 1 to 6 and the polypropylene resin for injection molding used in Examples and Comparative Examples (manufactured by Nippon Polypro Co., Ltd., trade name “NOVATEC”, MA1B, MFR 21 g / 10 min) The measurement was performed as follows, and the results are shown in Table 1 below. Further, the tensile elastic modulus, tensile strength, bending elastic modulus, bending strength, and Charpy impact strength of the fiber reinforced resin molded body obtained in Examples 1 to 10 and the fiber reinforced resin molded body obtained in Comparative Example 1 were used. Was measured as follows, and the results are shown in Table 1 below.

(specific gravity)
It measured according to JISK7112.

(Tensile test)
A tensile test was conducted according to JIS K 7162 (1994), and the tensile modulus and tensile strength were measured. As a test piece, a dumbbell shape (A-type test piece) was used, and the distance between grips was 100 mm and the test speed was 1 m / min.

(Bending test)
A bending test was performed according to JIS K 7171 (2004), and the bending elastic modulus and bending strength were measured. As the test piece, a strip-shaped test piece having a length of 125 mm, a width of 12.6 mm, and a thickness of 5 mm was used, and the distance between fulcrums was 80 mm and the test speed was 1 mm / min.

(Charpy impact test)
A Charpy impact test (notched) was performed according to ASTM D256, and the Charpy impact strength was measured. As the test piece, a strip-shaped test piece similar to the bending test was used, and the impact speed was 3.47 m / s.

  As is clear from Table 1, the fiber reinforced resin molded articles formed using the fiber reinforced resin pellets of the Examples have high tensile elastic modulus, tensile strength, bending elastic modulus, bending strength, Charpy impact strength, It was excellent in rigidity and impact resistance. Moreover, it was also confirmed that the fiber reinforced resin pellets of the examples had good handleability and good moldability.

DESCRIPTION OF SYMBOLS 1 Fiber assembly 2 Fiber reinforced resin sheet 3 Fiber reinforced resin pellet 11 Lower mold 12 Upper mold 20 Multi-axis insertion warp 21a-21f Mixed yarn of natural plant fiber and thermoplastic synthetic fiber 26 Knitting needle 27, 28 Stitch Thread

Claims (6)

A fiber-reinforced resin pellet containing natural plant fibers and thermoplastic synthetic fibers,
The natural plant fiber is a reinforcing fiber, and the thermoplastic synthetic fiber melts into a matrix resin,
The fiber-reinforced resin pellet is a hexahedron and has at least four cut surfaces.   The fiber-reinforced resin pellet according to claim 1, wherein the natural plant fiber is at least one fiber selected from the group consisting of cotton, hemp, kapok and bamboo.   The fiber-reinforced resin according to claim 1 or 2, wherein a blending ratio of the natural plant fiber and the thermoplastic synthetic fiber is, by mass ratio, a range of natural plant fiber: thermoplastic synthetic fiber = 80: 20 to 20:80. pellet. A fiber aggregate containing natural plant fibers and thermoplastic synthetic fibers is press-molded at a temperature equal to or higher than the melting point of the resin constituting the thermoplastic synthetic fibers to form a fiber-reinforced resin sheet,
A method for producing a fiber reinforced resin pellet, comprising cutting the fiber reinforced resin sheet in both the length direction and the width direction to obtain a hexahedral fiber reinforced resin pellet having at least four cut surfaces.   The method for producing fiber-reinforced resin pellets according to claim 4, wherein the fiber assembly is at least one selected from the group consisting of wrap, sliver, nonwoven fabric, woven fabric and knitted fabric.   A fiber reinforced resin molded article, wherein a resin material containing fiber reinforced resin pellets according to any one of claims 1 to 3 is molded into a predetermined shape.

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