JP2022190471A - Thermoplastic resin prepreg and method for manufacturing the same - Google Patents

Abstract

To provide a prepreg that has a high surface smoothness and hardly causes deformation or wrinkle during thermal processing, and a method for manufacturing the prepreg.SOLUTION: There is provided a thermoplastic resin prepreg comprising: a fiber-reinforced base material; and a thermoplastic resin composition partially or wholly impregnated in the fiber-reinforced base material, wherein the thermoplastic resin composition contains a crystalline thermoplastic resin, a crystallinity obtained by differential scanning calorimetry of the crystalline thermoplastic resin in the thermoplastic resin prepreg is 25 to 50%, and a crystallinity obtained by wide-angle X-ray diffraction measurement is 3% or more.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a thermoplastic resin prepreg and a method for producing the same. More specifically, the present invention relates to a thermoplastic resin prepreg with high surface smoothness and high thermal processability during thermoforming, and a method for producing the same.

Fiber-reinforced composite materials, which consist of reinforcing fibers and resins, have features such as light weight, high strength, and high elastic modulus, and are widely used in aircraft, sports/leisure, and general industries. This fiber-reinforced composite material is often manufactured via a prepreg in which reinforcing fibers and a resin called matrix resin are integrated in advance.

Conventionally, thermosetting resins such as unsaturated polyester resins, epoxy resins, and polyimide resins are mainly used as matrix resins in the aerospace and industrial fields, which require advanced mechanical properties and heat resistance. It is However, these thermosetting resins have the drawback of being brittle and having poor impact resistance. Therefore, especially in the field of aerospace, the use of thermoplastic resins as matrix resins has been studied from the viewpoint of the impact resistance of composite materials to be obtained and molding costs.

Among thermoplastic resins, polyaryletherketones (PAEK) such as polyetheretherketone (PEEK) and polyetherketoneketone (PEKK) are excellent in heat resistance, chemical resistance, and mechanical strength in the aerospace field. Therefore, it is expected.

However, when a prepreg is produced using such a thermoplastic resin having a high melting point, irregularities may occur on the prepreg surface and the surface smoothness may not be sufficiently high. Moreover, deformation and wrinkles may occur when the prepreg is thermally processed at a high temperature.

US Pat. No. 5,300,005 discloses providing a thin layer of hot melt adhesive on the surface of a prepreg to improve lamination difficulties due to relatively imperfect uniformity and hardness of the composite surface. A method of manufacturing prepregs provides techniques for manufacturing prepregs that can be bonded together by applying sufficient heat and pressure.

In Patent Document 2, when thermoplastic resin prepregs are laminated together or insert (or outsert) molding is performed using thermoplastic prepregs, deterioration in mechanical properties due to the type of matrix resin itself of thermoplastic resin prepregs is described. A thermoplastic resin prepreg capable of efficiently improving the adhesiveness of the prepreg surface without causing the prepreg surface and ensuring desirable adhesiveness during molding of a preform and/or a composite molded article using the same, An object of the present invention is to provide a preform and a composite formed article and methods for producing them.

To solve this problem, the method of applying resin to the thermoplastic resin prepreg is due to the surface unevenness of the prepregs, so it does not lead to the elimination of the unevenness of the prepreg during molding. It is insufficient to suppress wrinkles without being able to

JP-A-2-1303 International publication WO2013/008720

An object of the present invention is to provide a prepreg that has high surface smoothness and that is less likely to be deformed or wrinkled during thermal processing, and to provide a method for producing the prepreg.

The present inventor believes that the cause of wrinkles that occur during heat processing is the internal stress remaining in the prepreg and the anisotropy of the matrix resin crystals, and the relaxation of such internal stress and the isotropic transformation of the matrix resin crystals was considered. As a result, the inventors have found that the above problems can be solved by setting the crystallinity of the matrix resin within a predetermined range. Further, the inventors have found that such adjustment of the crystallinity can be achieved by controlling the surface pressure and temperature conditions during the production of the prepreg, and have completed the present invention.

The present invention for achieving the above object is as described below.

[1] A thermoplastic resin prepreg comprising a fiber-reinforced base material and a thermoplastic resin composition partially or wholly impregnated in the fiber-reinforced base material,
The thermoplastic resin composition contains a crystalline thermoplastic resin,
In the thermoplastic resin prepreg, the crystallinity obtained by differential scanning calorimetry of the crystalline thermoplastic resin is 25 to 50 [%], and the crystallinity obtained by wide-angle X-ray diffraction measurement is 3 [%]. ] A thermoplastic resin prepreg characterized by the above.

[2] The thermoplastic resin prepreg according to [1], wherein the proportion of the crystalline thermoplastic resin in the thermoplastic resin composition is 60 to 100 [mass %].

[3] The thermoplastic resin prepreg according to [1], wherein the crystalline thermoplastic resin has a glass transition temperature of 100[° C.] or higher.

[4] The thermoplastic resin prepreg according to [1], wherein the crystalline thermoplastic resin is polyetherketoneketone.

[5] The thermoplastic resin prepreg according to [1], wherein the fiber-reinforced base material is composed of carbon fibers.

[6] A fiber-reinforced base material and a thermoplastic resin composition containing a crystalline thermoplastic resin, wherein part or all of the thermoplastic resin composition is impregnated into the fiber-reinforced base material. A method for producing a thermoplastic resin prepreg comprising:
In a state in which the thermoplastic resin composition is impregnated in the fiber-reinforced base material, or when the thermoplastic resin composition is impregnated in the fiber-reinforced base material, the melting point of the thermoplastic resin composition is Pressurize and heat with
Next, a method for producing a thermoplastic resin prepreg, characterized by pressurizing and cooling to a glass transition temperature or lower of the crystalline thermoplastic resin while applying a surface pressure of 0.5 to 7.5 [MPa].

[7] The method for producing a thermoplastic resin prepreg according to [6], wherein the surface pressure during pressurization and heating is 0.5 to 7.5 [MPa].

[8] The method for producing a thermoplastic resin prepreg according to [6], wherein the pressurized heating and the pressurized cooling are performed by a double belt press device.

[9] The method for producing a thermoplastic resin prepreg according to [6], wherein the proportion of the crystalline thermoplastic resin in the thermoplastic resin composition is 60 to 100 [mass%].

[10] The method for producing a thermoplastic resin prepreg according to [6], wherein the crystalline thermoplastic resin has a glass transition temperature of 100[°C] or more.

[11] The method for producing a thermoplastic resin prepreg according to [6], wherein the crystalline thermoplastic resin is polyetherketoneketone.

[12] The method for producing a thermoplastic resin prepreg according to [6], wherein the fiber-reinforced base material is made of carbon fiber.

The thermoplastic resin prepreg of the present invention has high surface smoothness before thermoforming, and is less likely to be deformed or wrinkled during thermal processing. Therefore, the moldability of the fiber-reinforced composite material can be enhanced.

The present invention will be described in detail below.
In the specification of the present application, prepreg is a type of fiber-reinforced composite material, and refers to a state before becoming a fiber-reinforced composite material having a particularly desired shape. A fiber-reinforced composite material refers to a material after it has been molded into a desired shape.

1. Thermoplastic resin prepreg The thermoplastic resin prepreg of the present invention is a thermoplastic resin prepreg comprising a fiber-reinforced base material and a thermoplastic resin composition partially or wholly impregnated in the fiber-reinforced base material. is.
In the thermoplastic resin prepreg of the present invention, the crystalline thermoplastic resin exists at a crystallinity of 25 to 50 [%] obtained by differential scanning calorimetry, and a crystallinity obtained by wide-angle X-ray diffraction measurement. exists at 3 [%] or more.

(1) Fiber Reinforcing Substrate The reinforcing fiber used as the reinforcing fiber substrate of the present invention is not particularly limited, and examples thereof include carbon fiber, glass fiber, aramid fiber, silicon carbide fiber, polyester fiber, ceramic fiber, alumina fiber, boron Fibers, metal fibers, mineral fibers, rock fibers, slag fibers and the like.

Among these reinforcing fibers, carbon fibers, glass fibers, and aramid fibers are preferred. Carbon fiber is more preferable because it has good specific strength and specific modulus, and provides a lightweight and high-strength fiber-reinforced composite material. Polyacrylonitrile (PAN)-based carbon fibers are particularly preferred because of their excellent tensile strength.

When PAN-based carbon fiber is used as the reinforcing fiber, its tensile modulus is preferably 100 to 600 [GPa], more preferably 200 to 500 [GPa], and 230 to 450 [GPa]. is particularly preferred. Further, the tensile strength is preferably 2000 to 10000 [MPa], more preferably 3000 to 8000 [MPa]. The diameter of the carbon fiber is preferably 4-20 [μm], more preferably 5-10 [μm]. By using such carbon fibers, the mechanical properties of the resulting fiber-reinforced composite material can be improved.

In the present invention, the reinforcing fiber base material may be a reinforcing fiber bundle, or may be used as a reinforcing fiber sheet in which reinforcing fibers are formed into a sheet. It is more preferable to use a reinforcing fiber sheet in which reinforcing fibers are formed into a sheet. As the reinforcing fiber sheet, for example, a sheet (UD sheet) in which a large number of reinforcing fibers are aligned in one direction, a laminated sheet in which a plurality of UD sheets are laminated with the fiber direction aligned or the fiber direction changed, Bidirectional woven fabrics such as plain weaves and twill weaves, multiaxial woven fabrics, non-woven fabrics, mats, knits, braids, and paper made from reinforcing fibers can be mentioned. Among these, UD sheets, laminated sheets, bidirectional woven fabrics, and multiaxial woven fabric substrates formed by forming reinforcing fibers into a sheet form as continuous fibers can be used to obtain fiber-reinforced composite materials with more excellent mechanical properties. preferable. The thickness of the sheet-like reinforcing fiber base material is preferably 0.01 to 3 [mm], more preferably 0.1 to 1.5 [mm].

The content of the fiber-reinforced base material in the entire thermoplastic resin prepreg of the present invention is preferably 40 to 85 [mass%], more preferably 45 to 80 [mass%], based on the total mass of the prepreg. more preferred. When the resin content is within this range, a fiber-reinforced composite material with better mechanical properties can be obtained. If the fiber content is too high, voids and the like may occur in the resulting fiber-reinforced composite material, degrading mechanical properties. If the fiber content is too low, the reinforcing effect of the fibers may be insufficient, resulting in substantially low mechanical properties relative to mass.

(2) Thermoplastic resin composition The thermoplastic resin composition constituting the prepreg of the present invention contains a crystalline thermoplastic resin as an essential component, and optionally an amorphous thermoplastic resin, filler, pigment, etc. may contain It usually does not contain thermosetting resin.

The crystalline thermoplastic resin is not particularly limited as long as it is a crystalline thermoplastic resin. Specifically, polyolefin resins such as polyethylene and polypropylene; polystyrene resins such as polystyrene, ABS, and AS; polyester resins such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT); nylon 6 (polycaproamide). , Polyamide resins such as nylon 66 (polyhexamethylene adipamide), nylon 12 (polydodecanamide); polycarbonate (PC) resin; polyphenylene sulfide (PPS) resin; polyethersulfone (PES) resin; polyketone resin; Ketone (PEK) resin; polyetheretherketone (PEEK) resin; polyetherketoneketone (PEKK) resin; polyimide (PI) resin; polyamideimide (PAI) resin; In particular, polyether ketone ketone (PEKK) resin is preferred. These crystalline thermoplastic resins may be contained singly or in combination of two or more.

The glass transition temperature of the crystalline thermoplastic resin is preferably 100 [° C.] or higher, more preferably 120 [° C.] or higher, and particularly preferably 130 [° C.] or higher. The upper limit of the glass transition temperature is preferably 280[°C] or less, more preferably 230[°C] or less, and particularly preferably 180[°C] or less. If the glass transition temperature is too low, the resulting fiber-reinforced composite material will have low heat resistance, which is undesirable. If the glass transition temperature is too high, workability will be low, making it difficult to form a prepreg.

The melting point of the thermoplastic resin composition is preferably 200 [° C.] or higher, more preferably 250 [° C.] or higher, further preferably 280 [° C.] or higher, and 300 [° C.] or higher. It is particularly preferred to have The upper limit of the melting point is 400[°C] or less, preferably 380[°C] or less, and particularly preferably 360[°C] or less. When the melting point of the thermoplastic resin composition is within this range, a prepreg having excellent moldability can be obtained. If the melting point of the thermoplastic resin composition is too high, the thermoplastic resin constituting the prepreg and the additives contained in the prepreg may be thermally decomposed, and the resulting fiber-reinforced composite material may have poor physical properties.

The crystalline thermoplastic resin in the prepreg of the present invention has a degree of crystallinity of 25 to 50 [%] obtained by differential scanning calorimetry, preferably 35 to 50 [%]. It is particularly preferred that it exists at 40 to 50 [%]. If the degree of crystallinity is too low, wrinkles are likely to occur during thermal processing due to the effect of volume change due to recrystallization of the amorphous portion.

In the present invention, the degree of crystallinity can be calculated based on the following formula by measuring the resin melting heat and recrystallization heat of the prepreg using a differential scanning calorimeter (DSC).

The degree of crystallinity obtained by differential scanning calorimetry increases when the recrystallization enthalpy of the sample in the above formula is small. One of the reasons for this is that it is difficult for scalding to occur. In this case, since the ratio of the amorphous portion in the sample increases, wrinkles are likely to occur due to the effect of volume relaxation of the amorphous portion during thermal processing, which is not preferable. Another factor that reduces the recrystallization enthalpy is the high degree of crystallinity of the sample subjected to differential scanning calorimetry, and this degree of crystallinity can be obtained by the following wide-angle X-ray diffraction measurement.

The crystalline thermoplastic resin in the prepreg of the present invention has a degree of crystallinity of 3.0% or more and 3.2% or more as measured by wide-angle X-ray diffraction. is preferred, and it is particularly preferred that it exists at 3.4 [%] or more. If the degree of crystallinity is too low, wrinkles are likely to occur during thermal processing due to the effect of volume change due to recrystallization of the amorphous portion, which is undesirable.

The proportion of the crystalline thermoplastic resin in the thermoplastic resin composition constituting the prepreg of the present invention is preferably 60 to 100 [mass%], more preferably 80 to 100 [mass%]. It is particularly preferable to be up to 100 [mass %]. If the proportion of the crystalline thermoplastic resin is too low, the problem of wrinkles during thermal processing of the prepreg is inherently difficult to occur, but the resulting fiber-reinforced composite material has low heat resistance.

2. Method for producing thermoplastic resin prepreg In the method for producing a thermoplastic resin prepreg of the present invention, the above thermoplastic resin composition is impregnated into the fiber reinforced base material, or the above thermoplastic resin is impregnated into the fiber reinforced base material. In impregnating the composition, the prepreg is produced by pressurizing and heating under predetermined conditions and then pressurizing and cooling. A method for manufacturing a thermoplastic resin prepreg will be described in detail below.
The method for producing the thermoplastic resin prepreg of the present invention is not particularly limited, and any conventionally known method can be employed. Specifically, a method of heat-sealing a reinforcing fiber base material to a film made of a thermoplastic resin composition (hot melt method), a method of immersing a reinforcing fiber base material in a solution or emulsion of a thermoplastic resin, drying it, and then melting it. , a method in which a reinforcing fiber base material is passed through a bed of thermoplastic resin powder and adhered thereto, and then heat-fused; A method (powder suspension method) of heating and melting the resin powder after adhering it to the substrate is exemplified. Among them, the powder suspension method is preferably used because the thermoplastic resin can be uniformly impregnated into the reinforcing fibers.

When the hot-melt method is used, any conventionally known method can be used as a method for forming a resin composition film from the thermoplastic resin composition. Specifically, using a die extrusion, an applicator, a reverse roll coater, a comma coater, etc., a resin composition film is obtained by casting the resin composition onto a support such as a release paper or a film. can be done. The resin temperature when producing the film is appropriately determined according to the composition and viscosity of the resin composition. The thermal fusion bonding of the resin composition to the reinforcing fiber base material and the impregnation into the fiber layer may be performed once or may be performed in multiple steps.

The powder suspension method uses a powdery thermoplastic resin composition. Considering good deposition on the fiber-reinforced base material (a state in which the resin powder is held between the fibers or on the surface of the fiber), the particle size of the thermoplastic resin powder is 50 [μm] or less, and from the point of handleability, it is 1 [μm] is preferable, and the average particle diameter is preferably in the range of 5 to 50 [μm]. The thermoplastic resin powder in the above particle size range has stable dispersibility (dispersibility of the resin powder in the suspension) when dispersed in the liquid described below. Resin powder can be stably deposited. The average particle size mentioned above is the value of the cumulative 50 volume % particle size (D50) of the particle size distribution measured using a laser diffraction/scattering method.

When used in the powder suspension method, it is preferable to use a liquid to disperse the thermoplastic resin powder. The liquid to be used is preferably one or more solvents or mixed solvents selected from water, alcohols, ketones, and halogenated hydrocarbons. Examples of alcohols include methanol, ethanol, isopropyl alcohol, methyl cellosolve, etc. Examples of ketones include acetone, methyl ethyl ketone, etc. Examples of halogenated hydrocarbons include methylene chloride, dichloroethane, and the like. Among them, ethanol, isopropyl alcohol, acetone, a mixed solvent of these and water, or water are preferable. Moreover, a commercial product containing the above solvent and having a suitable solvent composition can also be used, and Solmix (product name, manufactured by Nippon Alcohol Trading Co., Ltd.) is exemplified as such a commercial product. Such a liquid also has the effect of appropriately opening the fiber-reinforced base material, and is therefore effective in uniformly depositing the resin powder in the suspension on the fiber material.

As for the combination of the thermoplastic resin powder and the liquid (solvent) for dispersing it, the solvent is preferably a poor solvent for the thermoplastic resin and preferably does not dissolve the resin.

The concentration of the thermoplastic resin in the suspension [thermoplastic resin mass / (liquid mass + thermoplastic resin mass) x 100] is preferably 1 to 50 [mass%], more preferably 1 to 30 [mass%]. Preferably, 1 to 15 [mass %] is more preferable.

The temperature of the suspension when the reinforcing fiber base material is immersed is not particularly limited as long as the resin is kept well dispersed. ~50 [°C], preferably 5 to 30 [°C], more preferably 15 to 30 [°C].

The amount of the thermoplastic resin powder attached to the fiber-reinforced base material is preferably 10 to 70 [mass%] with respect to the total amount of the fiber-reinforced base material and the thermoplastic resin powder. ~50 [mass%] is more preferable.

The fiber-reinforced base material to which the thermoplastic resin powder is attached is usually dried at a temperature at which the thermoplastic resin does not decompose or react. The drying temperature is preferably 80 to 200 [° C.], and the drying time is preferably 1 to 20 [minutes] for production.

The reinforcing fiber base material to which the thermoplastic resin powder is adhered is pressurized and heated at a temperature equal to or higher than the melting point of the thermoplastic resin composition. By this treatment, the thermoplastic resin powder is softened or melted, the fiber-reinforced base material and the thermoplastic resin composition are integrated, and a heated thermoplastic resin prepreg is obtained. Next, the heated thermoplastic resin prepreg is pressurized and cooled to below the glass transition temperature of the crystalline thermoplastic resin contained in the thermoplastic resin composition. Thereby, the thermoplastic resin prepreg of the present invention is obtained. In this production method, the fiber-reinforced base material is impregnated with the thermoplastic resin composition, and the pressure and heat are applied. The impregnated thermoplastic resin prepreg may be pressurized and heated again.

The temperature during pressure heating is equal to or higher than the melting point of the thermoplastic resin composition, preferably 20[°C] or higher than the melting point, more preferably 30[°C] or higher. By heating to the melting point or higher, the internal stress remaining in the fiber-reinforced base material and the internal stress generated in the prepreg can be sufficiently relaxed. If the temperature during pressurization and heating is lower than the melting point, stress tends to remain in the thermoplastic resin prepreg to be obtained, and wrinkles may occur during thermal processing. As an example, when polyetherketoneketone (PEKK) resin is used as the thermoplastic resin, the heating temperature is preferably 350 to 400 [°C], more preferably 370 to 400 [°C].

The holding time above the melting point of the thermoplastic resin composition is preferably 10 to 60 [seconds], more preferably 20 to 30 [seconds].

The surface pressure during pressurization and heating is preferably 0.5 to 7.5 [MPa], more preferably 1.5 to 3.5 [MPa]. The surface smoothness of the thermoplastic resin prepreg is enhanced by applying a pressure of 0.5 [MPa] or more while heating to the melting point or higher. If the surface pressure is too high, wrinkles may occur during thermal processing, although the surface smoothness immediately after pressurization and heating is high. In addition, as a result of hindering movement of fibers and resin in the prepreg, internal stress may not be sufficiently relieved, and wrinkles may easily occur during thermal processing. When the surface pressure is within the above range, the fibers and resin can move appropriately, the internal stress is relieved, and the anisotropy of the thermoplastic resin crystals is less likely to occur.

The finishing temperature of pressurized cooling is equal to or lower than the glass transition temperature of the crystalline thermoplastic resin contained in the thermoplastic resin composition. By cooling under pressure to a temperature below the glass transition temperature, the surface smoothness of the thermoplastic resin prepreg can be improved, the crystallinity of the crystalline thermoplastic resin can be controlled, the obtained prepreg becomes isotropic, and heat processing is performed. Occasionally wrinkles can be suppressed. As an example, when polyether ketone ketone (PEKK) resin is used as the thermoplastic resin, the cooling end temperature is preferably 160 [° C.] or less, more preferably 155 [° C.] or less, and further preferably 150 [° C.] or less. .

The surface pressure during pressure cooling is preferably 0.5 to 7.5 [MPa], more preferably 1.5 to 3.5 [MPa]. By applying a pressure of 0.5 [MPa] or more during cooling, the surface smoothness of the thermoplastic resin prepreg can be improved, and the degree of crystallinity of the thermoplastic resin crystals is in an appropriate range, so the obtained prepreg is difficult to be anisotropic.

The cooling rate during pressurized cooling was such that the average cooling rate from (glass transition temperature + 150 [°C]) to the glass transition temperature was 80 [°C/sec. ] is preferably below. By setting the average cooling rate within this range, the crystallinity can be controlled within a preferred range.

There are no particular restrictions on the device used for pressurizing, heating, and pressurizing and cooling the reinforcing fiber base material to which the thermoplastic resin powder is adhered, and a heating roller, a heat press device, a double belt press device, or the like can be used. In particular, the double belt press apparatus is suitable for continuous production because it can press the prepreg while being conveyed by the upper and lower endless belts.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples and comparative examples. Moreover, the evaluation of wrinkles and the measurement of the degree of crystallinity in each example and comparative example were carried out by the following methods.

[Evaluation of wrinkles]
The presence or absence of wrinkles immediately after production of the thermoplastic resin prepreg of the present invention was visually evaluated. In addition, the thermoplastic resin prepreg was heated at 385[°C] for 5[minutes] and then further heated at 200[°C] for 5[minutes] to visually evaluate the presence or absence of wrinkles. The evaluation criteria are as follows.
O: Appearance is extremely good. The uniformity of the surface and the straightness of the fibers are ensured, and heat shrinkage does not occur.
Δ: Good appearance. The uniformity of the surface and the straightness of the fibers are ensured, and fine undulations are generated by heat shrinkage.
The appearance that does not have any problem to use it.
x: Poor appearance. Waviness occurred in the prepreg, the straightness of the fiber disappeared, and wrinkles occurred.

[Crystallinity obtained by differential scanning calorimetry]
The crystallinity was measured using a differential scanning calorimeter DSC. The degree of crystallinity was calculated based on the following formula.

Measuring device: Suggestive investigation calorimeter Q2000 manufactured by TA Instruments
Measurement condition:
Atmosphere: Nitrogen atmosphere Heating conditions Heating rate: 10 [°C/min]
Temperature range: 30 [°C] to 400 [°C]

[Crystallinity obtained by wide-angle X-ray diffraction measurement]
The degree of crystallinity is obtained by converting the obtained two-dimensional data into a 2θ profile, subtracting the CF component and performing baseline correction, then peak fitting the range of 2θ = 7 to 36 °, and calculating the integrated intensity of each peak. Crystallinity Xc was determined according to the following formula from Ic and Ia obtained by summing up the components and the amorphous component, respectively.

The following materials were used as raw materials for the prepreg.
[Thermoplastic resin particles]
・"Kepstan PT7002" (trade name) (polyether ketone ketone, Arkema, glass transition temperature 162 [°C], average particle size (D50) 20 [μm])
[Reinforcing fiber bundle]
・“Tenax” (trade name) HTS 45 P 12 12K (carbon fiber strand, manufactured by Teijin Limited, 12,000 filaments)

(Example 1)
The reinforcing fiber bundles were aligned in one direction to obtain a fiber-reinforced base material having a fiber basis weight of 194 [g/mm ² ]. Also, the thermoplastic resin particles were dispersed in ethanol to prepare a suspension solution with a concentration of 5.5 [% by mass].
The fiber-reinforced base material was then immersed in the suspension solution for 15 seconds to adhere the thermoplastic resin particles to the fiber-reinforced base material. After drying the obtained fiber-reinforced base material with resin in a drying oven at 100 [° C.] for 1 minute, it is passed through a plurality of heating bars with a surface temperature of 400 [° C.] to melt and impregnate the thermoplastic resin, A unidirectional thermoplastic resin prepreg was made. The content of carbon fibers in the entire prepreg was set to 57 [volume %].
Using a double belt press (hydraulic double belt press, manufactured by Morita Giken Co., Ltd.), the thermoplastic resin prepreg was pressurized and heated, and then pressurized and cooled to obtain a thermoplastic resin prepreg.
A preheating roller, two heating rollers, three cooling rollers, and a preheating roller were provided in the apparatus in order from the prepreg inlet, and pressure was applied between the heating roller and the cooling roller. The maximum temperature reached by the heating roller portion and the temperature at the exit of the cooling roller portion were defined as the heating temperature and the cooling temperature, respectively, as shown in Table 1. The set pressures of the heating roller and the cooling roller were set as shown in Table 1.

(Comparative Examples 1 to 3)
In the apparatus, a preheating roller, two heating rollers, three cooling rollers, and a preheating roller were provided in order from the prepreg inlet, and the heating temperature and cooling temperature were as described in Table 1. A thermoplastic resin prepreg was obtained in the same manner as in 1.

As shown in Table 1, the thermoplastic resin prepreg of Example 1 had almost no wrinkles immediately after production and during the wrinkle test. On the other hand, the thermoplastic resin prepreg of Comparative Example 1 was wrinkled immediately after production and during the wrinkle test because it was not subjected to pressure heating and pressure cooling. In the thermoplastic resin prepreg of Comparative Example 4, since the surface pressure during pressurization and heating was too high, the surface of the prepreg became smooth, but wrinkles occurred during the wrinkle test. The thermoplastic resin prepregs of Comparative Examples 2 and 3 had a high end temperature of pressurized cooling, and thus the surfaces of the prepregs were not smooth.

Claims (12)

A thermoplastic resin prepreg comprising a fiber-reinforced base material and a thermoplastic resin composition partially or wholly impregnated in the fiber-reinforced base material,
The thermoplastic resin composition contains a crystalline thermoplastic resin,
In the thermoplastic resin prepreg, the crystallinity obtained by differential scanning calorimetry of the crystalline thermoplastic resin is 25 to 50 [%], and the crystallinity obtained by wide-angle X-ray diffraction measurement is 3 [ %] or more. 2. The thermoplastic resin prepreg according to claim 1, wherein the proportion of said crystalline thermoplastic resin in said thermoplastic resin composition is 60 to 100 [mass %]. The thermoplastic resin prepreg according to claim 1, wherein the crystalline thermoplastic resin has a glass transition temperature of 100 [°C] or higher. 2. The thermoplastic resin prepreg according to claim 1, wherein said crystalline thermoplastic resin is polyetherketoneketone. 2. The thermoplastic resin prepreg according to claim 1, wherein said fiber-reinforced base material is composed of carbon fibers. A thermoplastic resin composition comprising a fiber-reinforced base material and a thermoplastic resin composition containing a crystalline thermoplastic resin, wherein part or all of the thermoplastic resin composition is impregnated in the fiber-reinforced base material A method for manufacturing a resin prepreg,
In a state in which the thermoplastic resin composition is impregnated in the fiber-reinforced base material, or when the thermoplastic resin composition is impregnated in the fiber-reinforced base material, the melting point of the thermoplastic resin composition is Pressurize and heat with
Next, a method for producing a thermoplastic resin prepreg, characterized by pressurizing and cooling to a glass transition temperature or lower of the crystalline thermoplastic resin while applying a surface pressure of 0.5 to 7.5 [MPa]. 7. The method for producing a thermoplastic resin prepreg according to claim 6, wherein the surface pressure during pressurization and heating is 0.5 to 7.5 [MPa]. 7. The method for producing a thermoplastic resin prepreg according to claim 6, wherein said pressurized heating and said pressurized cooling are performed by a double belt press device. 7. The method for producing a thermoplastic resin prepreg according to claim 6, wherein the proportion of the crystalline thermoplastic resin in the thermoplastic resin composition is 60 to 100 [mass %]. 7. The method for producing a thermoplastic resin prepreg according to claim 6, wherein the crystalline thermoplastic resin has a glass transition temperature of 100 [° C.] or more. 7. The method for producing a thermoplastic resin prepreg according to claim 6, wherein the crystalline thermoplastic resin is polyetherketoneketone. 7. The method for producing a thermoplastic resin prepreg according to claim 6, wherein the fiber-reinforced base material is made of carbon fiber.