JP2016056491A - Fiber sheet for fiber-reinforced resin and production method of the same, and molded body using the same and production method of the molded body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fiber sheet for a fiber-reinforced resin, which enhances wettability with a matrix resin and reduces voids, and a production method of the same, and a molded body using the same and a production method of the molded body.SOLUTION: In a fiber sheet (1) for a fiber-reinforced resin, a large number of fiber bundles (2) are formed by sewing shape-retaining yarns (3) into fiber layers arranged in a direction or with a predetermined angle, in which the shape-retaining yarn (3) has been subjected to at least one surface treatment selected from a group of ozone oxidation, ultraviolet irradiation of light with a wavelength of 400 nm or less, and plasma treatment such that an advancing contact angle and a receding contact angle of the shape-retaining yarn (3) to water are reduced.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fiber sheet for fiber reinforced resin with improved resin impregnation, a method for producing the same, a molded body using the same, and a method for producing the same.

  Carbon fiber reinforced plastics (CFRP: Carbon Fiber Reinforced Plastics) are widely used in various sports equipment such as golf club shafts, fishing rods, aircraft, automobiles, pressure vessels, etc. Future applications are also expected. As a general molding method of fiber reinforced resin, for example, a contact pressure molding method such as a hand lay-up method or a spray-up method, a continuous molding method such as a filament winding (FW) method, a drawing method or a continuous lamination method is used. To the desired molded product. As the matrix resin to be used, a thermosetting resin such as an epoxy resin is used. In order to increase the bonding strength with the matrix resin, a sizing agent corresponding to the matrix resin is attached to the reinforcing fiber surface (Non-Patent Document 1).

  As a prior art, there is a proposal to use a sizing agent for carbon fiber having an acrylic group and an epoxy group (Patent Document 1). There is also a proposal for ozone oxidation of the carbon fiber surface before the sizing agent is attached (Patent Document 2). Furthermore, there is a proposal of using a carbon fiber sizing agent having an epoxy group (Patent Documents 3 to 4).

JP 2000-355884 A JP 2009-79344 A JP-A-7-279040 JP 2005-146429 A

Textile Society edition, “Third edition fiber manual”, Maruzen, December 15, 2004, 598-601, 614-615

  However, the conventional reinforcing fiber sheet has a problem that it is difficult to impregnate the matrix resin. In particular, the fiber sheet for fiber reinforced resin integrated with the shape-retaining yarn in the fiber layer arranged in one direction or at a predetermined angle has a problem that the matrix resin is difficult to be impregnated when the matrix resin is injected. . Further, particularly when a molded body is produced by laminating a plurality of fiber layers, there is a problem that voids (cavities) are generated in a portion where the shape retaining yarn is present inside the molded body.

  In order to solve the above conventional problems, the present invention improves the wettability with the matrix resin, facilitates the impregnation of the matrix resin between the reinforced resin fibers, and reduces the generation of internal voids, and the production thereof. A method, a molded body using the method, and a method for producing the same are provided.

  The method for producing a fiber sheet for fiber reinforced resin according to the present invention is a method for producing a fiber sheet for fiber reinforced resin in which fiber layers arranged in one direction or at a predetermined angle are integrated with a shape-retaining yarn. The shape yarn is subjected to at least one surface treatment selected from the group consisting of ozone oxidation, ultraviolet irradiation with a wavelength of 400 nm or less, and plasma treatment.

  The fiber sheet for fiber-reinforced resin of the present invention is a fiber sheet for fiber-reinforced resin in which fiber layers arranged in one direction or at a predetermined angle are integrated with a shape-retaining yarn, and the shape-retaining yarn is against water. The advancing dynamic contact angle is 75 ° or less, and the receding dynamic contact angle is 30 ° or less.

  The fiber reinforced resin molded article of the present invention is a fiber formed by laminating a plurality of fiber reinforced resin fiber sheets obtained by the above production method and impregnating a matrix resin into the fiber reinforced resin fiber sheet by injection molding. It is a reinforced resin molded product, wherein bubbles inside the molded product are 0.2 area% or less.

  The fiber reinforced resin molded body of the present invention is a fiber reinforced resin molded body formed by laminating a plurality of the fiber reinforced resin fiber sheets and impregnating a matrix resin into the fiber reinforced resin fiber sheet by injection molding. And the bubble inside a molded object is 0.2 area% or less, It is characterized by the above-mentioned.

  The method for producing a molded product for fiber reinforced resin according to the present invention is a method for producing the molded product for fiber reinforced resin, wherein the shape-retaining yarn is subjected to ozone oxidation in a yarn state or a fiber sheet state, and has a wavelength of 400 nm or less. At least one surface treatment selected from the group consisting of ultraviolet irradiation and plasma treatment is performed, a plurality of fiber reinforced resin fiber sheets containing the shape-retaining yarn are laminated, and a matrix is formed in the fiber reinforced resin fiber sheet by injection molding. A molded article is molded by impregnating a resin.

  INDUSTRIAL APPLICABILITY The present invention can provide a fiber sheet for a fiber reinforced resin that is easy to impregnate a matrix resin between fibers by increasing the wettability with the matrix resin by subjecting the shape retaining yarn to an activation treatment such as ozone oxidation. Especially for fiber reinforced resins that are easily impregnated with matrix resin when multiple fiber sheets for fiber reinforced resin, in which fiber layers arranged in one direction or at a predetermined angle are integrated with shape-retaining yarns, are laminated and injection molded. A fiber sheet can be provided. This is because the shape retention yarn is activated so that the wettability with the matrix resin is high, and when the shape retention yarn is a knitting yarn, the matrix resin easily diffuses from the stitch hole of the knitting yarn. It is thought that.

FIG. 1A is a plan view of the surface of a fiber sheet for fiber reinforced resin according to an embodiment of the present invention, and FIG. 1B is a plan view showing the back surface thereof. FIG. 2 is a conceptual perspective view of a multi-axis inserted warp knitted fabric showing another embodiment of the present invention. FIG. 3 is a plan view of the surface of a fiber sheet for fiber-reinforced resin according to still another embodiment of the present invention. FIG. 4 is a plan view of the surface of a fiber sheet for fiber-reinforced resin according to still another embodiment of the present invention. FIG. 5 is a schematic view for explaining infusion molding according to an embodiment of the present invention.

  The present invention consists of ozone irradiation, ultraviolet irradiation with a wavelength of 400 nm or less such as irradiation with an excimer lamp and low pressure mercury lamp, and plasma irradiation on the shape retaining yarn itself or the shape retaining yarn incorporated in the fiber sheet for fiber reinforced resin. By performing at least one surface treatment selected from the group, the contact angle of the shape-retaining yarn with respect to water is reduced, and as a result, the wettability with the matrix resin is improved, and a fiber sheet that is easily impregnated with the matrix resin between the reinforcing fibers. Can be provided. If the matrix resin is easily impregnated between the reinforcing fibers, there are advantages that the molded body has fewer defects and that the impregnation process can be shortened.

  The contact angle with water can be reduced by subjecting the shape-retaining yarn to at least one surface treatment selected from the group consisting of ozone oxidation, ultraviolet irradiation with a wavelength of 400 nm or less, and plasma treatment. The yarn contact angle is measured by the forward dynamic contact angle and the backward dynamic contact angle when the yarn is inserted into water. If it is not preferable to measure the thickness of the film by another method, for example, a film may be prepared using a resin of the same material, and the contact angle may be increased by dropping water on the film.

  The shape retaining yarn preferably has a forward dynamic contact angle of 75 ° or less and a backward dynamic contact angle of 30 ° or less. When the shape retaining yarn is a polyester yarn, the advancing dynamic contact angle is 79 ° without the surface treatment, and the receding dynamic contact angle is 35 °. This is important for increasing the wettability with the matrix resin. The advancing dynamic contact angle of the shape retaining yarn with respect to water is preferably 50 to 75 °, and the receding dynamic contact angle is preferably 3 to 30 °, more preferably the advancing dynamic contact angle 65 to 72 °, and the receding dynamic contact angle 5 ~ 20 °. The preferred fineness of the shape retaining yarn is 1 to 30 tex, preferably 2 to 25 tex, more preferably 3 to 20 tex. If it is the said range, the production efficiency of the sewing process by a shape-retaining thread is high.

  The shape retaining yarn is preferably a knitting yarn, a weaving yarn or a scrim. Knitting yarns are used in uniaxial or multi-axially inserted warp knitting, weaving yarns are used in woven fabrics, and scrims are used to form a large number of fiber sheets, for example by thermal bonding with a net material. The shape retention yarn may be a heat fusion yarn or may include a heat fusion yarn. Usually, the shape retaining yarn is a polyester yarn or a nylon yarn. If it does in this way, resin impregnation property can further be improved. Glass yarn is used as an auxiliary yarn.

Carbon fiber, glass fiber, or aramid fiber can be used as the fiber for fiber reinforced resin, and carbon fiber or glass fiber is preferable among them. It can also be used for reinforcing fibers called super fibers. The basis weight of the fiber sheet for fiber reinforced resin is preferably 50 to 2500 g / m ² , more preferably 150 to 2000 g / m ² , and particularly preferably 400 to 1500 g / m ² .

Next, each surface treatment will be described.
(1) Ozone oxidation Methods for generating ozone include a silent discharge method, a creeping discharge method, an ultraviolet irradiation method, and an electrolysis method. The silent discharge method is mainly used for generating large-volume ozone from the viewpoint of efficiency. At present, this is the most commonly used discharge method as a discharge type ozonizer. When a dielectric (mainly glass or ceramics) layer is provided on one or both of the pair of parallel electrodes and an alternating high voltage is applied between the two electrodes, silent discharge occurs. A preferable example of the ozone concentration is 40000 ppm. The treatment time is preferably 2 to 60 minutes, more preferably 5 to 40 minutes. Since ozone diffuses uniformly into the treatment space, it is suitable for the treatment of the fiber sheet for fiber reinforced resin. That is, not only the surface of the fiber sheet for fiber reinforced resin but also the inside can be treated uniformly.

(2) Excimer lamp irradiation An excimer lamp is a discharge that emits light from a rare gas atom or an excimer formed by a rare gas atom and a halogen atom, taking advantage of the fact that a large number of dielectric barrier discharges occur for a short time. It is a lamp. Typical emission wavelengths of excimer lamps include Ar2 * (126 nm), Kr2 * (146 nm), Xe2 * (172 nm), KrCl * (222 nm), XeCl * (308 nm), and the like. The lamp has a double structure of quartz glass. A metal electrode is applied to the inside of the inner tube, a metal mesh electrode is applied to the outside of the outer tube, and a discharge gas is filled in the quartz glass tube. When an alternating high voltage is applied to the electrodes, a large number of thin wire-like discharge plasmas (dielectric barrier discharges) are generated between the two dielectrics. This discharge plasma contains high-energy electrons and has the feature of disappearing instantaneously. The discharge plasma excites the atoms of the discharge gas and instantaneously enters an excimer state. When returning from the excimer state to the original state (ground state), the excimer-specific spectrum is emitted (excimer emission). The emission spectrum can be set by the filled discharge gas. Preferred irradiation conditions vary depending on the wavelength. In the case of a wavelength of 172 nm, when the light intensity is 5 to 6 mW / cm ² , for example, the irradiation time is preferably about 0.5 to 30 minutes. In the case of a wavelength of 222 nm, if the light intensity is 40 to 60 mW / cm ² , for example, the irradiation time is preferably about 2 to 30 minutes. If there is an air layer (gap) between the lamp and the object to be processed, in the case of a wavelength of 172 nm, oxygen in the air absorbs light energy to generate ozone, so that an oxidizing action by ozone also occurs.

(3) Low-pressure mercury lamp irradiation Low-pressure mercury lamps (low-pressure UV lamps) use arc discharge in mercury vapor with a mercury pressure of 100 Pa or less during operation. The arc tube is filled with a rare gas such as argon gas and mercury or its amalgam. There are lamps of ultraviolet radiation with wavelengths of 185nm and 254nm. The light intensity is, for example, 40 to 60 mW / cm ² . The irradiation time is preferably about 2 to 30 minutes.

(4) Plasma irradiation treatment In general, plasma is in a state where molecules constituting a gas are partially or completely ionized, and are freely moving into cations and electrons. Conditions using a plasma processing apparatus for plasma irradiation to carbon fibers, when expressed in watt density (W · min / m ²⁾ as the amount of irradiation, preferably 1000～50000W · min / m ^2. Further, a treatment speed (workpiece moving speed) of 0.05 to 1 m / min is preferable in an atmosphere of nitrogen gas or nitrogen + oxygen gas.

  The above surface treatments may be used alone or in any combination. By these surface treatments, the shape-retaining yarn surface can be activated, the wettability with the matrix resin can be improved, and the impregnation property can be further enhanced. Of the above surface treatments, ozone oxidation is most preferable. This is because ozone oxidation can be processed in the gas phase, so that not only the surface of the fiber sheet but also the inside can be uniformly processed.

  The plurality of fibers are formed in a sheet shape. Examples of such fibers include a suede-like base material in which constituent fibers are aligned in one direction, a woven fabric, a knitted fabric, a braid, a multi-axis inserted warp knitted fabric, and the like. The single fiber fineness of the fibers constituting the fiber sheet may be any fineness.

  The molded body of the present invention is a fiber reinforced resin molded body obtained by laminating a plurality of fiber sheets for fiber reinforced resin and molded by injection molding, and the bubbles inside the molded body are 0.2 area% or less. Examples of injection molding include infusion molding and RTM molding. Infusion molding is a closed mold molding method in which a film is used for the upper mold, the lower mold and the film are kept airtight, and the resin is filled and impregnated by vacuum pressure. The bubbles inside the molded body are preferably measured by an X-ray transmission CT scan. Usually, the number of laminated fiber sheets for fiber reinforced resin is 3 to 300. When the number of stacked layers is small, the original void is unlikely to occur. Therefore, as an effect of reducing the generation of voids according to the present invention, the more effective number of stacked layers is 20 to 300, and the number of stacked layers that is particularly effective is 50. ~ 300. Examples of this molded body include a blade for wind power generation, a boat, and sports equipment.

  For the fiber sheet for fiber-reinforced resin of the present invention, it is preferable to use a sheet having a highly versatile epoxy resin sizing agent attached to the carbon fiber surface. The preferable adhesion amount of the sizing agent is 0.1 to 5.0% by weight, more preferably 0.2 to 3.0% by weight.

  The matrix resin is preferably a thermosetting resin, and examples thereof include resins such as epoxy, unsaturated polyester, phenol, and vinyl ester.

  Next, it demonstrates using drawing. In the following drawings, the same symbols indicate the same items. FIG. 1A is a plan view of the surface of the fiber sheet 1 for fiber-reinforced resin according to one embodiment of the present invention, and FIG. 1B is a plan view showing the back surface thereof. On the surface side of the fiber sheet 1, polyester yarn yarns 3 are knitted in a zigzag shape, and a large number of fiber bundles 2 are arranged in the vertical direction. The reinforcing fiber layer is a single layer. On the back side of the fiber sheet 1, a knitting yarn 3 is knitted in the vertical direction, and a glass fiber filament yarn 4 is knitted together with the fiber bundle 2 with the knitting yarn 3 in the horizontal direction.

  FIG. 2 is a conceptual perspective view of a multi-axis inserted warp knitted fabric 10 showing another embodiment of the present invention. The multi-axis inserted warp knitted fabric 10 is formed in a thickness direction by reinforcing fiber layers 5 arranged in the horizontal direction and shape retaining yarns 8 and 9 hung on the knitting needle 7 by reinforcing fiber layers 6 arranged in the vertical direction. And sew together. Such a multi-axis inserted warp knitted fabric is used as the fiber sheet 10 and is integrally formed with the matrix resin. This multiaxial laminate sheet can obtain a fiber reinforced resin excellent in multidirectional reinforcement effect. As the shape retention yarn, a heat fusion yarn may be used instead of the polyester yarn, or a combination thereof may be used.

  FIG. 3 is a plan view of the surface of a fiber sheet 11 for fiber-reinforced resin according to still another embodiment of the present invention. In the fiber sheet 11 for fiber reinforced resin, the shape retaining yarn 13 is woven into the weft yarn, and a large number of fiber bundles 12 are arranged in the vertical direction.

  FIG. 4 is a plan view of the surface of a fiber sheet 14 for fiber-reinforced resin according to still another embodiment of the present invention. The fiber sheet 14 for fiber reinforced resin is retained by heat bonding using a scrim 16 in a net shape.

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

<Measurement of dynamic contact angle between shape-retaining yarn and water>
The impregnation between the shape retaining yarn and the matrix resin was considered to correlate with the affinity between the shape retaining yarn and water, and the dynamic contact angle between the shape retaining yarn and water was measured. Measuring instruments and measuring methods are as follows.
(a) Measuring equipment (surface tension meter)
Manufacturer: Biolin Scientific (Distributor in Japan: Altech)
Measuring instrument: Sigma700
(b) Measuring method The dynamic contact angles (advancing contact angle and receding contact angle) of the shape retaining yarn were calculated by measuring hysteresis. First, three shape-retaining yarns are juxtaposed in parallel and attached to aluminum foil, and the three shape-retaining yarns are simultaneously impregnated in water to a certain depth so that they are perpendicular to water (distilled water), and then pulled out. Three cycles were performed. The hysteresis of these three cycles was measured, and the advancing contact angle and the receding contact angle were calculated.
(c) Measurement conditions
Speed up: 5 mm / min
Speed down: 5 mm / min
Start depth: -1 mm
Immersion depth: 3 mm
Ignore first: 0 mm
Wait when up: 0 sec
Wait when down: 0 sec
Sample interval: 0 sec
Detect range: 5 mN / m
Return position: 5 mm
Return speed: 40 mm / min
R (circumference length) * 3 conversion: 0.14 mm
(d) Calculation method The advancing contact angle and receding contact angle are calculated by hysteresis measurement and the following formula.
Wetting force = γLVRcosθ (γLV: surface tension of solution, R: circumference of sample, θ: contact angle)
Calculation software is incorporated in the surface tension meter.

<Measurement of void fraction by X-ray transmission CT>
Using an X-ray transmission CT system manufactured by Toshiba, model "TOSCANER-30000", the observation area, void area and void on one screen under the conditions of tube voltage 180kV, tube current 140μA, 64μm / pixel (screen size) Area% was determined by image processing. The image processing method is incorporated in this X-ray transmission CT apparatus.

(Example 1)
Carbon fiber (50K) manufactured by SGL, shape: large toe filament, single fiber fineness 7 μm, total fineness 3300 tex was used as the reinforcing fiber. Polyethylene terephthalate multifilament yarn (fineness: 8.3 tex, mass per unit area: 9.3 g / m ² , gauge number: 5 / inch, tricot knitting, width: about 5.08 mm) A zigzag pitch of about 1.7 mm) and a glass filament yarn (fineness: 34 tex, mass per unit area: 10 g / m ² , gauge number: 7.5 / inch) as the weft on the back surface is shown in FIG. The fiber sheet 1 shown to -B was created. The width of one fiber bundle 2 was about 5 mm. This fiber sheet is a unidirectional substrate.

  The obtained fiber sheet was subjected to ozone oxidation treatment. A fiber sheet (size of one fiber sheet: vertical and horizontal 200 mm, thickness of about 0.9 mm) was placed in a chamber and contacted with an ozone atmosphere (concentration 40000 ppm) for 30 minutes for ozone oxidation treatment. The ozone generator was manufactured by Mitsubishi Electric Corporation, ozone generation amount: 50 g / h, maximum ozone concentration: 40,000 ppm, generation method: silent discharge.

  When the shape retention yarn was taken out of the fiber sheet after the ozone oxidation treatment and the dynamic contact angle was measured, the forward dynamic contact angle was 69 ° and the backward dynamic contact angle was 7 °.

The obtained fiber sheet (one-way substrate) after the ozone oxidation treatment is arranged on a glass plate in a size of 200 mm each of length and width, and 22 sheets are laminated in the same direction, and the mass per unit area is about 15.9 kg / The fiber base material was m ² . This was molded according to the infusion molding method shown in FIG. Reference numeral 20 denotes an infusion molding apparatus. A fiber base material 23 is placed on a glass mat 22 on a glass base 21, a release cloth 24 and a resin dispersion plate 25 are placed thereon, and a resin film (vacuum bag) is placed thereon. ) 26 and the periphery was sealed with sealants 27a and 27b. An exhaust pipe 33 sealed by a seal portion 31 is connected to one end of a resin film (vacuum bag) 26, and vacuum was drawn from the exhaust pipe 33 in the direction of the arrow. After that, the valve 32 of the resin supply pipe 29 that was sealed and fixed to the upper part of the resin film (vacuum bag) 26 by the seal portion 30 was opened, and the matrix resin 28 was supplied to the fiber base material 23. When the matrix resin 28 is supplied to the fiber base material 23, the fiber base material 23 gets wet, so that the time until the matrix resin arrives at any part of the glass mat is measured by observing from the lower surface of the glass mat 22. . The matrix resin used was mixed with the following epoxy resin (manufactured by HUNTSMAN) (viscosity 200 to 320 mPa · s (25 ° C.)).
Main agent: Araldaite LY1564SP: 100 parts by weight Curing agent: Aradur 3416: 34 parts by weight

(Comparative Example 1)
The experiment was performed in the same manner as in Example 1 except that the ozone oxidation treatment was not performed.

  The dynamic contact angles of Example 1 and Comparative Example 1 are summarized in Table 1.

  Next, Table 2 summarizes the results obtained by laminating a plurality of fiber substrates of Example 1 and Comparative Example 1 and measuring the time for impregnation to the back surface of the fiber substrate in infusion molding. The molded body using the base material of Example 1 had a lower internal void than the molded product using the base material of Comparative Example 1. The time until impregnation is the time until the matrix resin arrives at any part of the glass mat.

(Example 2 and Comparative Example 2)
Except for the point that the number of laminated fiber bases was changed to 50, a fiber reinforced resin molded article was prepared by matching other conditions with Example 1 and Comparative Example 1. The molded body was subjected to measurement of the void ratio by X-ray transmission CT scan, and the measurement results are summarized in Table 3. In addition, it is as follows about the measurement of a void ratio. First, with respect to an X-ray transmission CT scan tomographic photograph of a cut section of a molded body, noise is removed by using a morphological process such as an expansion / contraction process, and a dark spot is extracted as a void part compared with the surrounding area. Subsequently, binarization processing is performed at a threshold level 80 on the density of 0 to 255. Furthermore, by reversing the black-and-white image, white is expressed as a void part, and the void ratio is calculated using the area of the void part (number of pixels in the void part) and the total cross-sectional area, that is, the observation area (number of pixels in the observation area). It was measured.

The following can be understood from the above results.
(1) When the ozone oxidation treatment is performed, the shape retention yarn has a low dynamic contact with water, and when the shape retention yarn has a low dynamic contact angle, the fiber base material (laminated fiber sheet) is easily wetted with the matrix resin. The matrix resin is easily impregnated in the base material, and the impregnation time can be shortened.
(2) When the shape-retaining yarn of the fiber base is subjected to ozone oxidation, a good-quality molded body with few voids can be obtained because the matrix resin is easily impregnated in the fiber base during infusion molding.

  The fiber sheet for fiber reinforced resin of the present invention and a molded body using the same are widely applied to various sports equipment such as blades, boats, golf club shafts, fishing rods, etc. used in wind power generation, aircraft, automobiles, pressure vessels, etc. it can.

1, 11, 14 Fiber sheet for fiber reinforced resin 2, 12, 15 Fiber bundle 3, 8, 9, 16 Shape retaining yarn 4 Glass fiber filament yarn 5, 6 Reinforcing fiber layer 7 Knitting needle 10 Multi-axis inserted warp knitted fabric 20 Infusion molding apparatus 21 Glass base 22 Glass mat 23 Fiber substrate 24 Peeling cloth 25 Resin dispersion plate 26 Resin film (vacuum bag)
27a, 27b Sealant 28 Matrix resin 29 Resin supply pipes 30, 31 Seal part 32 Valve 33 Exhaust pipe

Claims (11)

A method for producing a fiber sheet for fiber reinforced resin in which fiber layers arranged in one direction or at a predetermined angle are integrated with a shape-retaining yarn,
The method for producing a fiber sheet for fiber reinforced resin, wherein the shape retaining yarn is subjected to at least one surface treatment selected from the group consisting of ozone oxidation, ultraviolet irradiation with a wavelength of 400 nm or less, and plasma treatment.   The method for producing a fiber sheet for fiber reinforced resin according to claim 1, wherein the shape retention yarn has a contact angle with water reduced by the surface treatment.   The method for producing a fiber sheet for fiber reinforced resin according to claim 1 or 2, wherein the shape retention yarn has a forward dynamic contact angle and a backward dynamic contact angle with water reduced by the surface treatment.   The method for producing a fiber sheet for fiber-reinforced resin according to claim 3, wherein the forward dynamic contact angle of the shape retaining yarn with respect to water is 75 ° or less and the backward dynamic contact angle is 30 ° or less.   The method for producing a fiber sheet for fiber reinforced resin according to any one of claims 1 to 4, wherein the shape retaining yarn is at least one selected from knitting yarn, woven yarn, and scrim.   The method for producing a fiber sheet for fiber reinforced resin according to any one of claims 1 to 5, wherein the fiber for fiber reinforced resin is at least one selected from the group consisting of carbon fiber and glass fiber. A fiber sheet for fiber reinforced resin in which fiber layers arranged in one direction or at a predetermined angle are integrated with a shape-retaining yarn,
The shape-retaining yarn has a forward dynamic contact angle with respect to water of 75 ° or less and a backward dynamic contact angle of 30 ° or less.   The shape retaining yarn has an advancing dynamic contact angle of 75 ° or less and a receding dynamic contact angle of 30 ° or less with respect to water by at least one surface treatment selected from the group consisting of ozone oxidation, ultraviolet irradiation with a wavelength of 400 nm or less, and plasma treatment. The fiber sheet for fiber reinforced resin according to claim 7, wherein the fiber sheet is set to ° or less. A fiber reinforcement formed by laminating a plurality of fiber sheets for fiber reinforced resin obtained by the production method according to claim 1 and impregnating a matrix resin into the fiber sheet for fiber reinforced resin by injection molding. A resin molded body,
A fiber-reinforced resin molded product, wherein the air bubbles in the molded product are 0.2% by area or less. A fiber reinforced resin molded article obtained by laminating a plurality of fiber sheets for fiber reinforced resin according to claim 7 or 8 and impregnating a matrix resin into the fiber sheet for fiber reinforced resin by injection molding. And
A fiber-reinforced resin molded product, wherein the air bubbles in the molded product are 0.2% by area or less. A method for producing a molded article for fiber reinforced resin in which the bubbles inside the molded article are 0.2 area% or less,
The shape-retaining yarn is subjected to at least one surface treatment selected from the group consisting of ozone oxidation, ultraviolet irradiation with a wavelength of 400 nm or less and plasma treatment in the yarn state or fiber sheet state,
A fiber reinforced resin molding characterized by laminating a plurality of fiber reinforced resin fiber sheets including the shape retaining yarn, and impregnating a matrix resin into the fiber reinforced resin fiber sheet by injection molding to form a molded body. Body manufacturing method.

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