JP2023018687A - Carbon fiber-reinforced molded body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carbon fiber-reinforced molded body having a high thickness, excellent in light-weight and high rigidity properties, not using a filler such as an inorganic filler easily generating uneven quality, not generating internal cracks, and having a high X-ray transmittance so as to be suitable for a dental member.

SOLUTION: A carbon fiber-reinforced molded body comprises an integrated material which is obtained by impregnating and curing a core material 11 having communication foam and a fiber reinforcement material 21 laminated on both surfaces of the core material 11 by a thermosetting resin. The thermosetting resin impregnated in the core material 11 and the fiber reinforcement material 21 contains a phenolic resin and polyvinyl butyral, or further contains an epoxy resin, and the polyvinyl butyral has a hydroxyl value of 24-27 mg/KOHg, and alcohol is used as the solvent.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2023,JPO&INPIT

Description

TECHNICAL FIELD The present invention relates to a carbon fiber reinforced molded article comprising a core material and fiber reinforcing materials laminated on both sides of the core material, and a method for producing the same.

Phenolic resins are used for components of electric appliances and automobile parts, etc., due to their excellent heat resistance and dimensional stability.
However, phenolic resin undergoes chemical and physical changes during the molding process, such as curing reactions and cooling, resulting in volumetric changes that tend to cause residual strain, resulting in cracks. be.

In order to solve the problem of cracks, it is common to add an inorganic filler such as glass fiber as a filler to the phenolic resin.
Patent Document 1 discloses a method of adding borosilicate glass beads as a filler.
Further, Patent Document 2 discloses a method of blending polyvinyl butyral and acrylonitrile-butadiene rubber with a phenol resin molding material containing glass fiber as a main filler.
On the other hand, in Patent Document 3, a fiber-reinforced molded body having excellent light weight, thin wall thickness, and high rigidity, which is suitable for the housing of portable equipment such as a notebook computer, is described. A fiber-reinforced fiber molding with a sandwich structure is shown.

JP 2009-102595 A JP-A-2000-273274 Japanese Patent No. 4558091

In the method of adding a filler such as an inorganic filler as disclosed in Patent Documents 1 and 2, the quality tends to vary due to uneven dispersion of the filler in the phenolic resin. In particular, dispersing the filler in a liquid tends to result in variations in quality due to sedimentation of the filler. In particular, the novolak-type phenolic resin is a thermoplastic resin that is solid at room temperature and consists of powder. It is used as a thermosetting resin by performing a cross-linking reaction using a curing agent.
Moreover, although Patent Document 2 claims that the static strength and toughness of the phenolic resin molding material are compatible, the results of Examples and Comparative Examples show that the effect is not sufficient.
In the fiber-reinforced molded body shown in Patent Document 3, there is no particular problem when the product thickness is as thin as 2 mm or less, but when the product thickness (thickness of the inner core layer) is increased, the inner core layer There is a problem that cracks are likely to occur in the

In addition, the patient's jaw and face must be fixed in order to perform imaging with the dental X-ray apparatus. A jig is used for this fixation, and jigs that come in contact with or close to the cheek are positioned on the left and right sides of the face so that the face is oriented straight. Since the jig is at this position, a resin molding having a high X-ray transmittance is required. Furthermore, a resin molded article with high transmittance is also effective as a member of an operating table. The high transmittance reduces the patient's exposure to radiation and enables imaging with low-power X-rays.

The present invention has been made in view of the above points, and is thick, lightweight, excellent in high rigidity, does not use fillers such as inorganic fillers that tend to cause uneven quality, does not cause internal cracks, and is free from X-rays. An object of the present invention is to provide a carbon fiber reinforced molded article with high transmittance.

The invention of claim 1 is a carbon fiber reinforced molded body in which a core material having open cells and fiber reinforcing materials laminated on both sides of the core material are impregnated and cured with a thermosetting resin, wherein the thermosetting resin is It is characterized by containing phenolic resin and polyvinyl butyral (PVB). A PVB resin having hydroxyl groups reacts with a phenolic resin to form a crosslinked structure. At this time, the thermoplastic PVB is incorporated into the crosslinked structure of the phenol. A PVB resin dissolved in alcohol is used in a liquid resol type phenolic resin. Since they are liquids, they have good compatibility, react easily, and are suitable for impregnation into fiber fabrics and the like. Further, by mixing the novolak type phenolic resin, which is solid at room temperature and powder, together with the curing agent and the PVB resin dissolved in alcohol, the PVB resin reacts with the phenolic resin to form a crosslinked structure.

The invention according to claim 2 is the thermosetting resin according to claim 1, wherein the content of the phenol resin is 70 to 95% by weight and the content of the polyvinyl butyral is 5 to 30% by weight in 100% by weight of the thermosetting resin. It is characterized by

The invention of claim 3 is characterized in that, in claim 1, the thermosetting resin contains an epoxy resin in addition to the phenolic resin and the polyvinyl butyral. Epoxy resins also have epoxy groups that can react with phenolic resins, resulting in cross-linking reactions.

The invention according to claim 4 is the thermosetting resin according to claim 3, wherein the content of the phenol resin is 70 to 85% by weight, the content of the polyvinyl butyral is 10 to 20% by weight, and the The content of the epoxy resin is 5-20% by weight.

The invention of claim 5 is characterized in that, in claim 3 or 4, the epoxy resin is bisphenol A propylene oxide-added diglycidyl ether. By using the bisphenol A propylene oxide-added diglycidyl ether, the phenolic resin existing on the surface of the prepreg can penetrate and impregnate the inside of the carbon fiber fabric during the manufacturing process of the molded product.

The invention of claim 6 is characterized in that, in any one of claims 1 to 5, the polyvinyl butyral has a hydroxyl group content of 24 to 27 wt % and uses alcohol as a solvent.

The invention according to claim 7 is characterized in that, in any one of claims 1 to 6, the thickness of the core material is 2 mm or more.

In the invention of claim 8, a thermosetting resin foam having open cells is impregnated with a thermosetting resin, and the core material hardened in a compressed state of the thermosetting resin foam and the carbon fiber fabric are heat-treated. A method for producing a carbon fiber reinforced molded body, which is made of a fiber reinforcing material impregnated with a curable resin and hardened, and in which the fiber reinforcing material is laminated and integrated on both sides of the core material, wherein the carbon fiber fabric is thermoset. an impregnation step of obtaining an impregnated carbon fiber fabric by impregnating it with a curable resin; a lamination step of placing the impregnated carbon fiber fabric on both sides of a thermosetting resin foam having open cells to obtain a laminate; and a compression heating step of compressing and heating the laminate, and the thermosetting resin in the impregnation step contains phenol resin and polyvinyl butyral dissolved in alcohol. Compression in the compression heating step of arranging the impregnated carbon fiber fabric on both sides of the thermosetting resin foam having open cells and compressing and heating the laminate may be performed by compressing the entire surface of the laminate, or A portion may be compressed to appropriately provide unevenness. Alternatively, one or both of the upper and lower molds may be provided with concave portions in advance, and an uneven surface having an appropriate shape may be provided on a part of one side or both sides of the laminate. At this time, a part of the laminate may be completely compressed.

According to the invention of claim 1, the thermosetting resin contains phenol resin and polyvinyl butyral, so that it is thick, lightweight, and highly rigid, and does not use fillers such as inorganic fillers that tend to cause uneven quality. , a carbon fiber reinforced molded article having high X-ray transmittance without causing internal cracks can be obtained.

According to the invention of claim 2, the content of the phenol resin in 100% by weight of the thermosetting resin is 70 to 95% by weight, and the content of polyvinyl butyral is 5 to 30% by weight. The thermosetting resin can be easily impregnated into the reinforcing material, and the occurrence of internal cracks in the carbon fiber reinforced molding can be prevented.

According to the invention of claim 3, by including polyvinyl butyral and epoxy resin in combination with phenol resin, phenol resin and the former (PVB) or phenol resin and the latter (epoxy resin), rather than a structure consisting of these alone A synergistic effect is recognized by using three components, and the occurrence of cracks in the carbon fiber reinforced molded body is reduced, the bending strength can be increased, the rigidity can be increased, and the strength can be improved.

According to the invention of claim 4, the content of the phenol resin in 100% by weight of the thermosetting resin is 70 to 85% by weight, the content of the polyvinyl butyral is 10 to 20% by weight, and the content of the epoxy resin is By setting the amount to 5 to 20% by weight, the thermosetting resin can be easily impregnated into the core material and the fiber reinforcing material, and the occurrence of internal cracks in the carbon fiber reinforced molding can be prevented. In addition, by setting the content of the phenolic resin and the polyvinyl butyral in the above range, the compatibility between the phenolic resin and the epoxy resin is improved, the thermosetting resin can be made uniform, and the surface of the carbon fiber reinforced molded body can be Good appearance.

According to the invention of claim 5, by using bisphenol A propylene oxide-added diglycidyl ether as the epoxy resin, the compatibility of the three components consisting of the phenol resin, polyvinyl butyral, and epoxy resin is increased, and the thermosetting resin is used. It can be made uniform, and impregnation of the core material and the fiber reinforcing material with the thermosetting resin can be improved.

According to the invention of claim 6, since the amount of hydroxyl groups in polyvinyl butyral is 24 to 27 wt%, the compatibility of the three components consisting of phenol resin, polyvinyl butyral, and epoxy resin is increased, and the thermosetting resin is uniformly distributed. can be made, and the surface appearance of the carbon fiber reinforced molded body is improved. In addition, when polyvinyl butyral is dissolved in alcohol and used, impregnation of the core material and the fiber reinforcing material with the thermosetting resin can be improved.

According to the seventh aspect of the invention, by setting the thickness of the core material to 2 mm or more, it is possible to reduce the occurrence of internal cracks in a thick carbon fiber reinforced molded body having a large thickness. When the thickness of the core material is 2 mm or less, the compressibility against the original thickness becomes high and the thickness of the molded product becomes thin. unlikely to occur.

According to the invention of claim 8, the carbon fiber is thick, lightweight, excellent in high rigidity, does not use a filler such as an inorganic filler that tends to cause uneven quality, does not cause internal cracks, and has a high X-ray transmittance. Reinforced moldings can be produced.

1 is a cross-sectional view of one embodiment of a carbon fiber reinforced molded body in the present invention; FIG. It is a figure which shows the process of one embodiment of the manufacturing method in this invention. FIG. 2 is a diagram showing the blending of thermosetting resins used in Examples and Comparative Examples. FIG. 4 is a diagram showing the structure, X-ray transmission amount, flexural modulus, flexural strength, and presence or absence of cracks in Examples and Comparative Examples.

The carbon fiber reinforced molded article of the present invention will be described below with reference to the drawings.
A carbon fiber reinforced molded body 10 according to one embodiment of the present invention shown in FIG. It is preferably used as a member that comes into contact with or close to the cheek during X-ray imaging of the teeth.

The carbon fiber reinforced molding 10 has a plate-like shape with a predetermined size and a thickness of 3 mm or more, preferably 5 to 10 mm. If the thickness of the carbon fiber reinforced molding 10 is less than 3 mm, the rigidity may be insufficient depending on the application. When the carbon fiber reinforced molded body 10 is used as a member that contacts or approaches the cheek during dental X-ray imaging, the part that is integrated with the carbon fiber reinforced molded body 10 is formed by injection molding or the like. By so-called outsert molding, it is appropriately formed at a predetermined position.

The core material 11 is formed by impregnating a thermosetting resin foam having open cells with a thermosetting resin, and curing the thermosetting resin in a compressed state of the thermosetting resin foam. The thickness of the core material 11 is preferably 2 mm or more, more preferably 3 to 9 mm. If the thickness of the core material 11 is less than 2 mm, the carbon fiber reinforced molding 10 may lack rigidity depending on the application.

The thermosetting resin foam having open cells is not particularly limited, and can be selected from, for example, urethane resin foam and melamine resin foam. Further, when the carbon fiber reinforced molded body 10 is required to be flame retardant, the thermosetting resin foam is preferably flame retardant. is suitable as the thermosetting resin foam. The original thickness of the thermosetting resin foam before compression is preferably 5 mm or more, more preferably 6 mm to 40 mm. When the original thickness is within this range, the thermosetting resin foam can be impregnated with an appropriate amount of thermosetting resin, the yield after heat compression is good, and the thickness of the core material 11 is set to 2 mm or more. be able to. In addition, if the original thickness of the thermosetting resin foam before compression is less than 5 mm, the amount of thermosetting resin that can be impregnated and retained in the thermosetting resin foam decreases. stiffness is reduced. The thermosetting resin foam preferably has a density of 5 to 80 kg/m ³ before compression from the viewpoints of ease of compression, impregnation, lightness and rigidity.

The thermosetting resin with which the thermosetting resin foam is impregnated includes phenolic resin and polyvinyl butyral to increase the rigidity of the carbon fiber reinforced molding 10 and prevent cracks in the core material 11 inside.

When the thermosetting resin consists of two components, phenolic resin and polyvinyl butyral, the content of the phenolic resin is 70 to 95% by weight, and the content of the polyvinyl butyral is 5%, based on 100% by weight of the thermosetting resin. ~30% by weight is preferred. When the content of the phenol resin is less than the above range, the rigidity of the carbon fiber reinforced molded body 10 becomes insufficient. When the content is reduced, cracks are likely to occur in the core material 11 .

The polyvinyl butyral has a hydroxyl group content of 24 to 27 wt %, and is preferably dissolved in alcohol before use. By setting the amount of hydroxyl groups of the polyvinyl butyral in the above range, the compatibility of the components contained in the thermosetting resin is increased, and the thermosetting resin can be made uniform, thereby constituting the core material 11. The impregnation of the thermosetting resin into the thermosetting resin foam having continuous cells and the fiber reinforcing material 12 is improved, the variation in hardness depending on the part of the carbon fiber reinforced molded body can be reduced, and the carbon fiber The appearance of the reinforced molded body is also improved. Further, by dissolving the polyvinyl butyral in alcohol and using it, the thermosetting resin can be well impregnated into the thermosetting resin foam having interconnected cells constituting the core material 11 and the fiber reinforcing material 12. Therefore, it is possible to reduce variations in hardness depending on the part of the carbon fiber reinforced molded body.

The thermosetting resin preferably contains an epoxy resin together with the phenolic resin and the polyvinyl butyral. When the thermosetting resin is composed of the three components of phenol resin, polyvinyl butyral, and epoxy resin, the bending strength of the carbon fiber reinforced molding can be increased, and the rigidity can be increased.

When the thermosetting resin consists of three components, the phenolic resin, the polyvinyl butyral, and the epoxy resin, the content of the phenolic resin in 100% by weight of the thermosetting resin is 70 to 85% by weight, and the content of the polyvinyl butyral is The content is preferably 10 to 20% by weight, and the content of the epoxy resin is preferably 5 to 20% by weight.

By setting the content of the three components in the thermosetting resin within the above range, the thermosetting resin foam constituting the core material 11 and the fiber reinforcing material 12 can be easily impregnated with the thermosetting resin. As a result, cracks can be prevented from occurring in the core material 11 inside the carbon fiber reinforced molded body 10 . Further, by setting the contents of the phenolic resin and the polyvinyl butyral in the thermosetting resin within the above range, the compatibility between the phenolic resin and the epoxy resin is improved, and the thermosetting resin is made uniform. The impregnation of the thermosetting resin foam and the fiber reinforcing material 12 constituting the core material 11 with the thermosetting resin is improved, and the variation in hardness depending on the part of the carbon fiber reinforced molded body can be reduced. , the appearance of the carbon fiber reinforced molding is improved.

Specific examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin, glycidylamine type epoxy resin, dicyclopentadiene type epoxy resin, phenol There are novolac epoxy resins, aliphatic epoxy resins, alicyclic epoxy resins, and the like. These may be used alone or in combination of two or more. Among them, bisphenol A type epoxy resin and bisphenol F type epoxy resin are preferable because of their excellent heat resistance and water resistance. More preferred is bisphenol A propylene oxide added diglycidyl ether. By using bisphenol A propylene oxide-added diglycidyl ether as the epoxy resin, the compatibility of the three components consisting of the phenol resin, the polyvinyl butyral, and the epoxy resin is increased, and the thermosetting resin can be made uniform, and the core The impregnation of the thermosetting resin into the material and the fiber reinforcing material can be improved, the variation in hardness depending on the part of the carbon fiber reinforced molded body can be reduced, and the appearance of the carbon fiber reinforced molded body can be improved.

The fiber reinforcing material 21 is formed by impregnating a carbon fiber fabric with a thermosetting resin and hardening it. The thickness of the fiber reinforcing member 21 on one side is preferably 0.2 to 3.0 mm. The carbon fiber fabric is excellent in light weight and high rigidity. In particular, it is preferable to use a weave method in which the fibers are not unidirectional. A triaxial weave made of yarn of The carbon fiber fabric preferably has a fiber weight of 90 to 400 g/m ² from the viewpoint of impregnation with thermosetting resin and rigidity.

The thermosetting resin with which the carbon fiber fabric is impregnated is the same as the thermosetting resin with which the core material 11 is impregnated, and contains the phenol resin and the polyvinyl butyral, and more preferably the epoxy resin. It contains

The integration of the core material 11 and the fiber reinforcing material 21 is performed by compressing the laminate of the thermosetting resin foam impregnated with the thermosetting resin and the carbon fiber fabric, and at that time, compressing the carbon fiber The thermosetting resin impregnated in the woven fabric is impregnated into the thermosetting resin foam having open cells constituting the core material 11, and in that state, the thermosetting resin is cured by heating. be able to.
In addition, the fiber reinforcing members 21 on both sides of the core member 11 are not limited to one layer, and may be formed by stacking a plurality of layers.

The carbon fiber reinforced molding 10 preferably has a specific gravity of 1.4 or less, an X-ray transmittance of 8500 or more, a bending elastic modulus (GPa) of 40 or more, and a bending strength (MPa) of 300 or more.
The amount of X-ray transmission was measured using an X-ray transmission apparatus μRay8000 manufactured by Matsusada Precision Co., Ltd., and the brightness obtained when measured under the measurement conditions of tube voltage of 60 kV, output of 10 W, radiation source position of 0 mm, and camera position of 0 mm. The luminance peak value of the histogram (vertical axis: number of pixels, horizontal axis: luminance) was taken as the amount of X-ray transmission. That is, it refers to the luminance value (horizontal axis) at the maximum pixel value (vertical axis). It can be said that the larger the numerical value of the permeation amount, the better the permeability.

The specific gravity is measured according to JIS Z8801.
For the measurement of the amount of X-ray transmission, an image measured by an X-ray transmission apparatus was expressed as a luminance histogram, and the luminance at which the number of pixels peaked was defined as the amount of transmission. By setting the amount of X-ray transmission of the carbon fiber reinforced molded body 10 within the above range, the reinforced molded body can be used in dentistry as a member that contacts or approaches the cheek during X-ray imaging of teeth. .
The bending elastic modulus is measured according to JIS K7074. By setting the flexural modulus of the carbon fiber reinforced molded body 10 within the above range, the rigidity can be increased.
The bending strength is measured according to JIS K7074. By setting the bending strength of the carbon fiber reinforced molded body 10 within the above range, high rigidity can be achieved.
The rigidity of the carbon fiber reinforced molded body is determined by both the flexural modulus and the flexural strength. The greater the value of both, the higher the rigidity, and the lower the value of either one, the lower the rigidity. be judged.

Next, a method for manufacturing the fiber-reinforced molding 10 of the present invention will be described.
The method for producing the fiber-reinforced molded article 10 of the invention comprises an impregnation step, a lamination step, and a compression heating step.
In the impregnation step, as shown in (2-1) of FIG. 2, the carbon fiber fabric 21A is impregnated with the thermosetting resin 21B to form the impregnated carbon fiber fabric 21C. The carbon fiber fabric 21A and the thermosetting resin 21B are as described in the carbon fiber reinforced molding 10. As shown in FIG. The thermosetting resin 21B used for impregnation is an uncured liquid.

In order to facilitate the impregnation, the thermosetting resin 21B is preferably dissolved in a solvent. After impregnation, the impregnated carbon fiber fabric 21C should be dried at a temperature that does not cause a curing reaction of the thermosetting resin. removes the solvent from the impregnated carbon fiber fabric 21C. Even when the polyvinyl butyral is dissolved in alcohol and used, the solvent is removed by drying the impregnated carbon fiber fabric 21C at a temperature that does not cause a curing reaction of the thermosetting resin.

The impregnation means can be carried out by an appropriate method such as a method of immersing the carbon fiber fabric 21A in a tank containing the liquid thermosetting resin 21B, a method of spraying, a method of using a roll coater, or the like.

In the lamination step, as shown in (2-2) in FIG. 2, the impregnated carbon fibers obtained in the impregnation step (2-1) are placed on both sides of the thermosetting resin foam 11A having open cells. The woven fabric 21C is arranged to form the laminate 10A. The thermosetting resin foam 11A having open cells is as described in the carbon fiber reinforced molding 10. In the laminating operation, the impregnated carbon fiber fabric 21C, the thermosetting resin foam 11A, and the impregnated carbon fiber fabric 21C, the thermosetting resin foam 11A, and the impregnated carbon fiber fabric 21C are placed on the upper surface of the press molding lower mold 31 used in the compression heating step (2-3). The carbon fiber fabric 21C may be piled up in this order. The impregnated carbon fiber fabric 21C and the open-cell thermosetting resin foam 11A preferably have the same plane size. do it.

In the compression heating step, as shown in (2-3) of FIG. 2, the laminate 10A is compressed and heated by a lower mold 31 and an upper mold 33 for press molding. The degree of compression is such that the impregnated carbon fiber fabric 21 has a thickness of 2 mm or more. The distance between the press-molding lower mold 31 and the upper mold 33 was changed to actually produce a fiber-reinforced molded body, and the thickness of the core material of the obtained fiber-reinforced molded body was measured. The distance between the press-molding lower die 31 and the upper die 33 is found to give a thickness of . During the compression heating step, a spacer is installed at an appropriate position between the press-molding lower mold 31 and the upper mold 33 so that the press-molding lower mold 31 and the upper mold 33 are separated by a predetermined distance (thickness of the core material). is a predetermined thickness). Although the method of heating the laminate is not particularly limited, heating means such as heaters are provided in the press-molding lower mold 31 and the upper mold 33, and the laminate is heated through the press-molding lower mold 31 and the upper mold 33. is easy. The heating temperature is higher than the curing reaction temperature of the impregnated thermosetting resin.

When the laminate 10A is compressed during the compression heating step, the thermosetting resin impregnated in the impregnated carbon fiber fabric 21C of the laminate 10A is extruded from the impregnated carbon fiber fabric 21C, and the impregnated carbon fiber fabric 21C is extruded. The thermosetting resin foam 11A having the communicating cells in contact with the carbon fiber fabric 21C is impregnated, and the entire laminate 10A is impregnated. The thermosetting resin with which the entire laminate 10A is impregnated starts a curing reaction by heating, and when the laminate 10A is compressed, that is, the thermosetting resin foam 11A having the communication cells is compressed. Harden. As a result, the core material 11 is formed from the thermosetting resin foam 11A having interconnected cells, and the fiber reinforcing material 21 is formed from the impregnated carbon fiber fabric 21C. The carbon fiber reinforced molding 10 is formed by integrating the reinforcing members 21 . After that, the heat compression is released to obtain the carbon fiber reinforced molding 10 .

Thus, in the method for producing a fiber-reinforced molded article of the present invention, a thermosetting resin foam having open cells is impregnated with a thermosetting resin, and the thermosetting resin foam is cured in a compressed state. A method for producing a fiber-reinforced molded article, comprising a core material and a fiber reinforcing material obtained by impregnating and curing a carbon fiber fabric with a thermosetting resin, wherein the fiber reinforcing material is laminated and integrated on both sides of the core material. an impregnation step of impregnating a carbon fiber fabric with a thermosetting resin to obtain an impregnated carbon fiber fabric; and placing and laminating the impregnated carbon fiber fabric on both sides of a thermosetting resin foam having open cells. and a compression heating step of compressing and heating the laminate. By compressing the laminate in the heating step, the thermosetting resin impregnated in the impregnated carbon fiber fabric is impregnated into the thermosetting resin foam having open cells, and the laminate is heated in the compression heating step. By curing the thermosetting resin impregnated in the impregnated carbon fiber fabric and the thermosetting resin foam having open cells, and the thermosetting resin in the thermosetting resin foam having open cells impregnated with the thermosetting resin foam to form the core material that is hardened in a compressed state, and the fiber reinforcing material that is hardened by impregnating the thermosetting resin into the carbon fiber fabric.

When the fiber reinforcing material 21 on both sides of the core material 11 is composed of a plurality of layers, in the lamination step, the impregnated carbon fiber fabric 21C is formed on both sides of the thermosetting resin foam 11A having open cells. are laminated, and then the compression heating step is performed, a fiber-reinforced molded body in which a plurality of layers of the fiber reinforcing material 21 are laminated on both sides of the core material 11 can be obtained.

Formulation No. 3 with the contents shown in FIG. Using the thermosetting resins No. 1 to No. 8, the carbon fiber reinforced moldings of Examples 1 to 11 and Comparative Examples 1 to 3 shown in FIG. manufactured.

The phenol resin used was PR-55791B manufactured by Sumitomo Bakelite Co., Ltd. (an ethanol solution with a resin concentration of 60 wt %). Note that the amount of phenolic resin in FIG. 3 is the amount of phenolic resin from which ethanol has been removed.

Polyvinyl butyral (PVB resin) was obtained by mixing and dissolving Mobital B30T, a product of Kuraray Co., Ltd., with a hydroxyl group content of 25 wt % and ethanol at a ratio of 1:9. The amount of polyvinyl butyral (PVB resin) in FIG. 3 is the amount of polyvinyl butyral (PVB resin) from which ethanol has been removed.

As the epoxy resin, bisphenol A propylene oxide-added diglycidyl ether, manufactured by ADEKA Co., Ltd., product name: ADEKA RESIN EP-4005 was used.

Formulation no. 1 consists of 95% by weight of phenolic resin, 5% by weight of polyvinyl butyral (PVB resin), and 0% by weight of epoxy resin.
Formulation no. 2 consists of 90% by weight of phenolic resin, 10% by weight of polyvinyl butyral (PVB resin), and 0% by weight of epoxy resin.
Formulation no. 3 consists of 80% by weight of phenolic resin, 20% by weight of polyvinyl butyral (PVB resin), and 0% by weight of epoxy resin.
Formulation no. 4 consists of 70% by weight of phenolic resin, 30% by weight of polyvinyl butyral (PVB resin), and 0% by weight of epoxy resin.
Formulation no. 5 consists of 80% by weight of phenolic resin, 10% by weight of polyvinyl butyral (PVB resin), and 10% by weight of epoxy resin.
Formulation no. 6 consists of 85% by weight of phenolic resin, 10% by weight of polyvinyl butyral (PVB resin), and 5% by weight of epoxy resin.
Formulation no. 7 consists of 70% by weight of phenolic resin, 10% by weight of polyvinyl butyral (PVB resin), and 20% by weight of epoxy resin.
Formulation no. 8 consists of 100% by weight of phenolic resin, 0% by weight of polyvinyl butyral (PVB resin), and 0% by weight of epoxy resin.

A plain weave carbon fiber fabric (manufactured by Toho Tex Co., Ltd., product name: W-3101, fiber weight: 200 g/m ² ) was immersed in the thermosetting resin solution, and after taking it out, it was naturally dried at room temperature of 25°C for 2 hours. It was dried and further dried in an atmosphere of 60° C. for 1 hour to form impregnated carbon fiber fabrics in the number corresponding to each example shown below. The carbon fiber fabric was cut into a plane size of 200×300 mm (weight: 12 g/sheet). The impregnated carbon fiber fabric after drying weighed 28 g per piece.

The thermosetting resin foam having open cells was a melamine resin foam (manufactured by BASF, product name: Basotect V3012, density 9 kg/m ³ ) cut into a plane size of 200 × 300 mm with a thickness according to each example. used.

Next, the impregnated carbon fiber fabric, the thermosetting resin foam having continuous cells, and the impregnated carbon fiber are placed on a lower mold (flat plate) made of SUS whose surface is coated with a release agent in advance. By arranging the woven fabrics in order, a laminate in which impregnated carbon fiber woven fabrics were arranged on both sides of a thermosetting resin foam having communicating cells was set on a lower mold for press molding.

With the laminate set on the press-molding lower mold, the laminate on the press-molding lower mold is subjected to a surface pressure of 10 MPa at 150 ° C. for 10 minutes, and the press-molding upper mold ( The thermosetting resin was reacted and cured in the compressed state by pressing with a flat plate), compressing and heating. At that time, the laminate was heated by casting heaters attached to the upper and lower press dies. In addition, between the press molding lower mold and the upper mold, a SUS spacer having a different thickness depending on each example and each comparative example was interposed, and the gap between the lower mold and the upper mold, that is, the compressed thickness of the laminate (fiber reinforced molding) The molded product thickness of the body) was adjusted. Thereafter, the press-molding lower and upper dies were cooled at room temperature and then opened to obtain a carbon fiber reinforced molded body in which the fiber reinforcing material was laminated and integrated on both sides of the core material. This carbon fiber reinforced molded body was trimmed to 170×260 mm to obtain carbon fiber reinforced molded bodies of Examples 1 to 11 and Comparative Examples 1 and 2. Comparative Example 3 is an example without a core material.

Regarding the carbon fiber reinforced moldings of Examples 1 to 11 and Comparative Examples 1 to 3, specific gravity (based on JIS Z 8801), thickness of molded product (total thickness), thickness of fiber reinforcing material and core material, X-ray transmission amount (maximum luminance in luminance histogram), bending elastic modulus (based on JIS K 7074), and bending strength (based on JIS K 7074) were measured. For internal cracks, an X-ray transmission device μRay8000 manufactured by Matsusada Precision Co., Ltd. is used, and the molded product is photographed under the conditions of a tube voltage of 60 kV, an output of 10 W, a radiation source position of 0 mm, and a camera position of 0 mm, and the presence or absence of internal cracks is checked. Confirmed visually. In addition, the thickness of each layer of the molded product was measured by cutting the molded product at an arbitrary cross section and observing the cut surface vertically with a scanning electron microscope (SEM) to observe and measure the thickness of each layer of the molded product.

In Example 1, formulation no. Impregnated carbon fiber fabric (thickness 0.25 mm) with 16 g (weight after solvent removal) of thermosetting resin (95% by weight of phenolic resin, 5% by weight of polyvinyl butyral (PVB resin), 0% by weight of epoxy resin) of 1. rice field. The impregnated carbon fiber fabric was laminated in a sandwich structure of thermosetting resin foam (40 mm) having open cells (8 sheets on each side, 8 sheets on the upper side and 8 sheets on the lower side) and placed in a mold. A 7.6 mm spacer was inserted between the upper and lower molds to produce a fiber-reinforced molded product.

The molded product of Example 1 has a molded product thickness of 7.6 mm, a thickness of each fiber reinforcing material of 2.0 mm, a thickness of the core material of 3.6 mm, a specific gravity of 1.32, an X-ray transmission amount of 9863, and a bending elastic modulus of 50 GPa. , bending strength of 321 MPa, and no cracks. The fiber-reinforced molded article of Example 1 is thick, lightweight, excellent in rigidity, does not use fillers such as inorganic fillers that tend to cause uneven quality, does not cause internal cracks, and has high X-ray transmittance. is.

In Example 2, formulation no. Impregnated carbon fiber fabric (thickness 0.25 mm) with 16 g (weight after solvent removal) of the thermosetting resin of 2 (90% by weight of phenolic resin, 10% by weight of polyvinyl butyral (PVB resin), 0% by weight of epoxy resin). rice field. The impregnated carbon fiber fabric was laminated in a sandwich structure of thermosetting resin foam (40 mm) having open cells (8 sheets on each side, 8 sheets on the upper side and 8 sheets on the lower side) and placed in a mold. A 7.6 mm spacer was inserted between the upper and lower molds to produce a fiber-reinforced molded product.

The molded product of Example 2 has a molded product thickness of 7.6 mm, a thickness of each fiber reinforcing material of 2.0 mm, a thickness of the core material of 3.6 mm, a specific gravity of 1.32, an X-ray transmission amount of 9850, and a bending elastic modulus of 48 GPa. , the bending strength was 334 MPa, and no cracks occurred. The fiber-reinforced molded article of Example 2 is thick, lightweight, and excellent in rigidity, does not use fillers such as inorganic fillers that tend to cause uneven quality, does not cause internal cracks, and has high X-ray transmittance. is.

In Example 3, formulation no. Impregnated carbon fiber fabric (thickness 0.25 mm) with 16 g (weight after solvent removal) of thermosetting resin (80% by weight of phenolic resin, 20% by weight of polyvinyl butyral (PVB resin), 0% by weight of epoxy resin) of 3. rice field. The impregnated carbon fiber fabric was laminated in a sandwich structure of thermosetting resin foam (40 mm) having open cells (8 sheets on each side, 8 sheets on the upper side and 8 sheets on the lower side) and placed in a mold. A 7.6 mm spacer was inserted between the upper and lower molds to produce a fiber-reinforced molded product.

The molded product of Example 3 has a molded product thickness of 7.6 mm, a thickness of each fiber reinforcing material of 2.0 mm, a thickness of the core material of 3.6 mm, a specific gravity of 1.32, an X-ray transmission amount of 9890, and a bending elastic modulus of 45 GPa. , bending strength of 349 MPa, and no cracks. The fiber-reinforced molded article of Example 3 is thick, lightweight, excellent in rigidity, does not use fillers such as inorganic fillers that tend to cause uneven quality, does not cause internal cracks, and has high X-ray transmittance. is.

In Example 4, formulation no. 4 thermosetting resin (70% by weight of phenolic resin, 30% by weight of polyvinyl butyral (PVB resin), 0% by weight of epoxy resin) 16 g (weight after solvent removal) is impregnated into carbon fiber fabric (thickness 0.25 mm). rice field. The impregnated carbon fiber fabric was laminated in a sandwich structure of thermosetting resin foam (40 mm) having open cells (8 sheets on each side, 8 sheets on the upper side and 8 sheets on the lower side) and placed in a mold. A 7.6 mm spacer was inserted between the upper and lower molds to produce a fiber-reinforced molded product.

The molded product of Example 4 has a molded product thickness of 7.6 mm, a thickness of each fiber reinforcing material of 2.0 mm, a thickness of the core material of 3.6 mm, a specific gravity of 1.33, an X-ray transmission amount of 9874, and a bending elastic modulus of 42 GPa. , bending strength of 356 MPa, and no cracks. The fiber-reinforced molded article of Example 4 is thick, lightweight, excellent in rigidity, does not use fillers such as inorganic fillers that tend to cause uneven quality, does not cause internal cracks, and has high X-ray transmittance. is.

In Example 5, formulation no. 6 thermosetting resin (85% by weight of phenolic resin, 10% by weight of polyvinyl butyral (PVB resin), 5% by weight of epoxy resin) 16 g (weight after solvent removal) is impregnated into carbon fiber fabric (thickness 0.25 mm). rice field. The impregnated carbon fiber fabric was laminated in a sandwich structure of thermosetting resin foam (20 mm) having open cells (8 sheets on each side, 8 sheets on the upper side and 8 sheets on the lower side) and placed in a mold. A 7.6 mm spacer was inserted between the upper and lower molds to produce a fiber-reinforced molded product.

The molded product of Example 5 has a molded product thickness of 2.5 mm, a thickness of each fiber reinforcing material of 0.25 mm, a thickness of the core material of 2.0 mm, a specific gravity of 1.29, an X-ray transmission amount of 13360, and a bending elastic modulus of 49 GPa. , bending strength of 408 MPa, and no cracks. The fiber-reinforced molded article of Example 5 has a thermosetting resin composed of three components, phenol resin, polyvinyl butyral (PVB resin), and epoxy resin. Bending strength is higher. The fiber-reinforced molded article of Example 5 is thick, lightweight, excellent in rigidity, does not use fillers such as inorganic fillers that tend to cause uneven quality, does not cause internal cracks, and has high X-ray transmittance. is.

In Example 6, formulation no. 6 thermosetting resin (85% by weight of phenolic resin, 10% by weight of polyvinyl butyral (PVB resin), 5% by weight of epoxy resin) 16 g (weight after solvent removal) is impregnated into carbon fiber fabric (thickness 0.25 mm). rice field. The impregnated carbon fiber fabric was laminated in a sandwich structure of thermosetting resin foam (40 mm) having open cells (8 sheets on each side, 8 sheets on the upper side and 8 sheets on the lower side) and placed in a mold. A 7.6 mm spacer was inserted between the upper and lower molds to produce a fiber-reinforced molded product.

The molded product of Example 6 has a molded product thickness of 5.0 mm, a thickness of each fiber reinforcing material of 1.5 mm, a thickness of the core material of 2.0 mm, a specific gravity of 1.38, an X-ray transmission amount of 10968, and a bending elastic modulus of 48 GPa. , the bending strength was 412 MPa, and no cracks occurred. Since the fiber-reinforced molded article of Example 6 is composed of three components, phenol resin, polyvinyl butyral (PVB resin), and epoxy resin, the thermosetting resin is different from that of Examples 1 to 4, which is composed of two components that do not contain epoxy resin. Bending strength is higher. The fiber-reinforced molded article of Example 6 is thick, lightweight, excellent in rigidity, does not use fillers such as inorganic fillers that tend to cause uneven quality, does not cause internal cracks, and has high X-ray transmittance. is.

In Example 7, formulation no. 6 thermosetting resin (85% by weight of phenolic resin, 10% by weight of polyvinyl butyral (PVB resin), 5% by weight of epoxy resin) 16g (weight after solvent removal) is impregnated into carbon fiber fabric (thickness 0.25mm). rice field. The impregnated carbon fiber fabric was laminated in a sandwich structure of 10 upper and lower thermosetting resin foams (20 mm) having open cells, 10 upper and 10 lower, and placed in a mold. A 7.0 mm spacer was inserted between the upper and lower molds to produce a fiber-reinforced molded product.

The molded product of Example 7 has a molded product thickness of 7.0 mm, a thickness of each fiber reinforcing material of 2.5 mm, a thickness of the core material of 2.0 mm, a specific gravity of 1.40, an X-ray transmission amount of 9632, and a bending elastic modulus of 47 GPa. , bending strength of 390 MPa, and no cracks. The fiber-reinforced molded article of Example 7 has a thermosetting resin composed of three components, phenol resin, polyvinyl butyral (PVB resin), and epoxy resin. Bending strength is higher. The fiber-reinforced molded article of Example 7 is thick, lightweight, excellent in rigidity, does not use fillers such as inorganic fillers that tend to cause uneven quality, does not cause internal cracks, and has high X-ray transmittance. is.

In Example 8, Formulation No. 6 thermosetting resin (85% by weight of phenolic resin, 10% by weight of polyvinyl butyral (PVB resin), 5% by weight of epoxy resin) 16g (weight after solvent removal) is impregnated into carbon fiber fabric (thickness 0.25mm). rice field. The impregnated carbon fiber fabric was laminated in a sandwich structure of thermosetting resin foam (40 mm) having open cells (8 sheets on each side, 8 sheets on the upper side and 8 sheets on the lower side) and placed in a mold. A 7.6 mm spacer was inserted between the upper and lower molds to produce a fiber reinforced molded product.

The molded product of Example 8 has a molded product thickness of 7.6 mm, a thickness of each fiber reinforcing material of 2.0 mm, a thickness of the core material of 3.6 mm, a specific gravity of 1.32, an X-ray transmission amount of 9863, and a bending elastic modulus of 47 GPa. , bending strength of 398 MPa, and no cracks. In the fiber-reinforced molded article of Example 8, the thermosetting resin is composed of three components, phenol resin, polyvinyl butyral (PVB resin), and epoxy resin, so compared with Example 4, which is composed of two components that do not contain epoxy resin. Bending strength is high. The fiber-reinforced molded article of Example 8 is thick, lightweight, and excellent in rigidity, does not use fillers such as inorganic fillers that tend to cause uneven quality, does not cause internal cracks, and has high X-ray transmittance. is.

In Example 9, Formulation No. 6 thermosetting resin (85% by weight of phenolic resin, 10% by weight of polyvinyl butyral (PVB resin), 5% by weight of epoxy resin) 16 g (weight after solvent removal) is impregnated into carbon fiber fabric (thickness 0.25 mm). rice field. The impregnated carbon fiber fabric was laminated in a sandwich structure with three upper and lower thermosetting resin foams (80 mm) having open cells, three upper layers, and three lower layers, and placed in a mold. A spacer of 10.0 mm was inserted between the upper and lower molds to produce a fiber-reinforced molding.

The molded product of Example 9 has a molded product thickness of 10.0 mm, a thickness of each fiber reinforcing material of 0.75 mm, a thickness of the core material of 8.5 mm, a specific gravity of 1.28, an X-ray transmission amount of 8858, and a bending elastic modulus of 45 GPa. , the bending strength was 435 MPa, and no cracks occurred. The fiber-reinforced molded article of Example 9 has a thermosetting resin composed of three components, phenol resin, polyvinyl butyral (PVB resin), and epoxy resin. Bending strength is higher. The fiber-reinforced molded article of Example 9 is thick, lightweight, excellent in rigidity, does not use fillers such as inorganic fillers that tend to cause uneven quality, does not cause internal cracks, and has high X-ray transmittance. is.

In Example 10, formulation no. Impregnated carbon fiber fabric (thickness 0.25 mm) with 16 g (weight after solvent removal) of 5 thermosetting resin (80% by weight of phenolic resin, 10% by weight of polyvinyl butyral (PVB resin), 10% by weight of epoxy resin). rice field. The impregnated carbon fiber fabric was laminated in a sandwich structure of thermosetting resin foam (40 mm) having open cells (8 sheets each on the upper and lower sides, 8 sheets on the upper side and 8 sheets on the lower side) and placed in a mold. A 7.6 mm spacer was inserted between the upper and lower molds to produce a fiber reinforced molded product.

The molded product of Example 10 has a molded product thickness of 7.6 mm, a thickness of each fiber reinforcing material of 2.0 mm, a thickness of the core material of 3.6 mm, a specific gravity of 1.32, an X-ray transmission amount of 9889, and a bending elastic modulus of 45 GPa. , the bending strength was 404 MPa, and no cracks occurred. The fiber-reinforced molded article of Example 10 has a thermosetting resin composed of three components, phenol resin, polyvinyl butyral (PVB resin), and epoxy resin. Bending strength is higher. The fiber-reinforced molded article of Example 10 is thick, lightweight, excellent in rigidity, does not use fillers such as inorganic fillers that tend to cause uneven quality, does not cause internal cracks, and has high X-ray transmittance. is.

In Example 11, formulation no. Impregnated carbon fiber fabric (thickness 0.25 mm) with 16 g of thermosetting resin (70% by weight of phenolic resin, 10% by weight of polyvinyl butyral (PVB resin), 20% by weight of epoxy resin) (weight after solvent removal). rice field. The impregnated carbon fiber fabric was laminated in a sandwich structure of thermosetting resin foam (40 mm) having open cells (8 sheets each on the upper and lower sides, 8 sheets on the upper side and 8 sheets on the lower side) and placed in a mold. A 7.6 mm spacer was inserted between the upper and lower molds to produce a fiber reinforced molded product.

The molded product of Example 11 has a molded product thickness of 7.6 mm, a thickness of each fiber reinforcing material of 2.0 mm, a thickness of the core material of 3.6 mm, a specific gravity of 1.32, an X-ray transmission amount of 9901, and a bending elastic modulus of 41 GPa. , the bending strength was 410 MPa, and no cracks occurred. The fiber-reinforced molded article of Example 11 has a thermosetting resin composed of three components, phenol resin, polyvinyl butyral (PVB resin), and epoxy resin. Bending strength is higher. The fiber-reinforced molded article of Example 11 is thick, lightweight, excellent in rigidity, does not use fillers such as inorganic fillers that tend to cause uneven quality, does not cause internal cracks, and has high X-ray transmittance. is.

In Comparative Example 1, formulation No. Impregnated carbon fiber fabric (thickness 0.25 mm) with 16 g (weight after solvent removal) of thermosetting resin (100% by weight of phenolic resin, 0% by weight of polyvinyl butyral (PVB resin), 0% by weight of epoxy resin) of 8. rice field. The impregnated carbon fiber fabric was laminated in a sandwich structure of a thermosetting resin foam (20 mm) having open cells (20 mm), one on each side, one on the upper side, and one on the lower side, and placed in a mold. A 2.5 mm spacer was inserted between the upper and lower molds to produce a fiber reinforced molded product.

The molded product of Comparative Example 1 has a molded product thickness of 2.5 mm, a thickness of each fiber reinforcing material of 0.25 mm, a thickness of the core material of 2.0 mm, a specific gravity of 1.29, an X-ray transmission amount of 13358, and a bending elastic modulus of 50 GPa. , bending strength of 210 MPa, and crack generation. Since the fiber-reinforced molded article of Comparative Example 1 consists of only one component, the thermosetting resin being a phenolic resin, the thickness of the molded article is the same, and the bending strength is extremely high compared to Example 5, which consists of three thermosetting resins. is low to The fiber-reinforced molded article of Comparative Example 1 has a problem of low rigidity and cracks in the core material.

In Comparative Example 2, formulation No. 8 thermosetting resin (100% by weight of phenolic resin, 0% by weight of polyvinyl butyral (PVB resin), 0% by weight of epoxy resin) 16 g (weight after solvent removal) is impregnated into carbon fiber fabric (thickness 0.25 mm). rice field. The impregnated carbon fiber fabric was laminated in a sandwich structure with three upper and lower thermosetting resin foams (80 mm) having open cells, three upper layers, and three lower layers, and placed in a mold. A spacer of 10.0 mm was inserted between the upper and lower molds to produce a fiber-reinforced molding.

The molded product of Comparative Example 2 has a molded product thickness of 10.0 mm, a thickness of each fiber reinforcing material of 0.75 mm, a thickness of the core material of 8.5 mm, a specific gravity of 1.28, an X-ray transmission amount of 8860, and a bending elastic modulus of 45 GPa. , flexural strength of 255 MPa, and cracks occurred. Since the fiber-reinforced molded article of Comparative Example 2 consists of only one component, the thermosetting resin being a phenolic resin, the thickness of the molded article is the same, and the bending strength is extremely high compared to Example 9, which consists of three thermosetting resins. is low to The fiber-reinforced molded article of Comparative Example 2 has a problem of low rigidity and cracks in the core material.

In Comparative Example 3, formulation No. 6 thermosetting resin (85% by weight of phenolic resin, 10% by weight of polyvinyl butyral (PVB resin), 5% by weight of epoxy resin) 16 g (weight after solvent removal) is impregnated into carbon fiber fabric (thickness 0.25 mm). , 30 sheets were prepared. Thirty sheets of the impregnated carbon fiber fabric were laminated and placed in a mold. A fiber-reinforced molded article was produced without using a thermosetting resin foam having communicating cells with a spacer of 7.0 mm between the upper and lower molds.

The molded article of Comparative Example 3 has a molded article thickness of 7.6 mm, a thickness of each fiber reinforcing material of 3.75 mm, no core material, a specific gravity of 1.55, an X-ray transmission amount of 9607, a flexural modulus of 55 GPa, and a flexural strength of 514. , no cracks occurred. Since the fiber-reinforced molded article of Comparative Example 3 does not have a core material, it has a higher specific gravity than those of Examples 1 to 4, 7, 8, 10, and 11, which have the same thickness, and has a heavy problem. Moreover, the manufacturing cost is also high.

As described above, the example products of the present invention are thick, lightweight, excellent in rigidity, do not use fillers such as inorganic fillers that tend to cause uneven quality, do not cause internal cracks, and have high X-ray transmittance. It is a highly fiber-reinforced molding. Therefore, the fiber-reinforced molded article of the present invention is thick, excellent in light weight and high rigidity, and suitable for applications requiring high X-ray transmittance.

REFERENCE SIGNS LIST 10 fiber reinforced molding 10A, 10B, 10C laminate 11 core material 11A thermosetting resin foam 11B thermosetting resin 11C impregnated thermosetting resin foam 21 fiber reinforcing material 21A carbon fiber fabric 21B thermosetting resin 21C Pre-impregnated carbon fiber fabric

A first aspect of the invention is a carbon fiber reinforced molded body in which a core material having open cells and fiber reinforcing materials laminated on both sides of the core material are impregnated and cured with a thermosetting resin, wherein the thermosetting resin is , phenolic resin and polyvinyl butyral (PVB). A PVB resin having hydroxyl groups reacts with a phenolic resin to form a crosslinked structure. At this time, the thermoplastic PVB is incorporated into the crosslinked structure of the phenol. A PVB resin dissolved in alcohol is used in a liquid resol type phenolic resin. Since they are liquids, they have good compatibility, react easily, and are suitable for impregnation into fiber fabrics and the like. Further, by mixing the novolak type phenolic resin, which is solid at room temperature and powder, together with the curing agent and the PVB resin dissolved in alcohol, the PVB resin reacts with the phenolic resin to form a crosslinked structure.

A second aspect of the invention is the aspect of the first invention , wherein the content of the phenol resin is 70 to 95% by weight and the content of the polyvinyl butyral is 5 to 30% in 100% by weight of the thermosetting resin. % by weight.

A third aspect of the invention is characterized in that, in the first aspect of the invention, the thermosetting resin contains an epoxy resin in addition to the phenolic resin and the polyvinyl butyral. Epoxy resins also have epoxy groups that can react with phenolic resins, resulting in cross-linking reactions.

A fourth aspect of the invention is the aspect of the third invention , wherein the content of the phenol resin is 70 to 85% by weight and the content of the polyvinyl butyral is 10 to 20% in 100% by weight of the thermosetting resin. % by weight, and the content of the epoxy resin is 5 to 20% by weight.

A fifth aspect of the invention is characterized in that in the third or fourth aspect of the invention , the epoxy resin is bisphenol A propylene oxide-added diglycidyl ether. By using the bisphenol A propylene oxide-added diglycidyl ether, the phenolic resin existing on the surface of the prepreg can penetrate and impregnate the inside of the carbon fiber fabric during the manufacturing process of the molded product.

According to a sixth aspect of the invention, in any one of the first to fifth aspects of the invention , the polyvinyl butyral has a hydroxyl group content of 24 to 27 wt % and uses alcohol as a solvent.

A seventh aspect of the invention is characterized in that, in any one of the first to sixth aspects of the invention, the thickness of the core material is 2 mm or more.

In an eighth aspect of the invention , a thermosetting resin foam having open cells is impregnated with a thermosetting resin, and a core material obtained by curing the thermosetting resin foam in a compressed state, and a carbon fiber fabric A method for producing a carbon fiber reinforced molded body, which is made of a fiber reinforcing material impregnated with a thermosetting resin and cured, and in which the fiber reinforcing material is laminated and integrated on both sides of the core material, wherein the carbon fiber fabric is heat-treated. An impregnation step of impregnating a curable resin to obtain an impregnated carbon fiber fabric, a lamination step of disposing the impregnated carbon fiber fabric on both sides of a thermosetting resin foam having open cells to obtain a laminate, and a compression heating step of compressing and heating the laminate, and the thermosetting resin in the impregnation step contains phenol resin and polyvinyl butyral dissolved in alcohol. Compression in the compression heating step of arranging the impregnated carbon fiber fabric on both sides of the thermosetting resin foam having open cells and compressing and heating the laminate may be performed by compressing the entire surface of the laminate, or A portion may be compressed to appropriately provide unevenness. Alternatively, one or both of the upper and lower molds may be provided with concave portions in advance, and an uneven surface having an appropriate shape may be provided on a part of one side or both sides of the laminate. At this time, a part of the laminate may be completely compressed.

According to the aspect of the first invention , since the thermosetting resin contains phenolic resin and polyvinyl butyral, it is thick, lightweight, and excellent in rigidity, and fillers such as inorganic fillers that tend to cause uneven quality can be used. It is possible to obtain a carbon fiber reinforced molded article with high X-ray transmittance without causing internal cracks.

According to the aspect of the second invention, the content of the phenol resin in 100% by weight of the thermosetting resin is 70 to 95% by weight, and the content of polyvinyl butyral is 5 to 30% by weight. The thermosetting resin can be easily impregnated into the fiber reinforcing material, and the occurrence of internal cracks in the carbon fiber reinforced molding can be prevented.

According to the aspect of the third invention , by including polyvinyl butyral and epoxy resin in combination with phenol resin, a structure of phenol resin and the former (PVB) or phenol resin and the latter (epoxy resin) alone A synergistic effect is recognized by using three components than that, the occurrence of cracks in the carbon fiber reinforced molded body is reduced, the bending strength can be increased, the rigidity can be increased, and the strength can be improved.

According to the fourth aspect of the invention , the content of the phenol resin in 100% by weight of the thermosetting resin is 70 to 85% by weight, the content of the polyvinyl butyral is 10 to 20% by weight, and the content of the epoxy resin By setting the content to 5 to 20% by weight, the thermosetting resin can be easily impregnated into the core material and the fiber reinforcing material, and the occurrence of internal cracks in the carbon fiber reinforced molding can be prevented. In addition, by setting the content of the phenolic resin and the polyvinyl butyral in the above range, the compatibility between the phenolic resin and the epoxy resin is improved, the thermosetting resin can be made uniform, and the surface of the carbon fiber reinforced molded body can be Appearance is improved.

According to the fifth aspect of the invention, by using bisphenol A propylene oxide-added diglycidyl ether as the epoxy resin, the compatibility of the three components consisting of the phenol resin, polyvinyl butyral, and epoxy resin is increased, and the thermosetting resin can be made uniform, and impregnation of the core material and the fiber reinforcing material with the thermosetting resin can be improved.

According to the aspect of the sixth invention , since the amount of hydroxyl groups in polyvinyl butyral is 24 to 27 wt%, the compatibility of the three components consisting of the phenol resin, polyvinyl butyral, and epoxy resin is increased, and the thermosetting resin is used. It can be made uniform, and the surface appearance of the carbon fiber reinforced molding is improved. In addition, when polyvinyl butyral is dissolved in alcohol and used, impregnation of the core material and the fiber reinforcing material with the thermosetting resin can be improved.

According to the seventh aspect of the invention, by setting the thickness of the core material to 2 mm or more, it is possible to reduce the occurrence of internal cracks in a thick carbon fiber reinforced molded body having a large thickness. When the thickness of the core material is 2 mm or less, the compressibility against the original thickness becomes high and the thickness of the molded product becomes thin. unlikely to occur.

According to the eighth aspect of the invention , the carbon is thick, lightweight, excellent in high rigidity, does not use a filler such as an inorganic filler that tends to cause quality unevenness, does not cause internal cracks, and has a high X-ray transmittance. Fiber-reinforced moldings can be produced.

Claims (8)

In a fiber-reinforced molded body in which a core material having open cells and fiber reinforcing materials laminated on both sides of the core material are impregnated and cured with a thermosetting resin,
The carbon fiber reinforced molded article, wherein the thermosetting resin contains phenolic resin and polyvinyl butyral. The carbon according to claim 1, wherein the content of the phenol resin is 70 to 95% by weight and the content of the polyvinyl butyral is 5 to 30% by weight in 100% by weight of the thermosetting resin. Fiber reinforced molding. 2. The carbon fiber reinforced molded article according to claim 1, wherein the thermosetting resin contains an epoxy resin in addition to the phenolic resin and the polyvinyl butyral. In 100% by weight of the thermosetting resin, the content of the phenol resin is 70 to 85% by weight, the content of the polyvinyl butyral is 10 to 20% by weight, and the content of the epoxy resin is 5 to 20% by weight. The carbon fiber reinforced molded article according to claim 3, characterized in that there is 5. The carbon fiber reinforced molded article according to claim 3, wherein the epoxy resin is bisphenol A propylene oxide added diglycidyl ether. The carbon fiber reinforced molded article according to any one of claims 1 to 5, wherein the polyvinyl butyral has a hydroxyl group content of 24 to 27 wt% and uses an alcohol as a solvent. The carbon fiber reinforced molded article according to any one of claims 1 to 6, wherein the core material has a thickness of 2 mm or more. A thermosetting resin foam having open cells is impregnated with a thermosetting resin, a core material obtained by curing the thermosetting resin foam in a compressed state, and a carbon fiber fabric impregnated with a thermosetting resin and cured. A method for producing a carbon fiber reinforced molded body made of a fiber reinforcing material and having the fiber reinforcing material laminated and integrated on both sides of the core material,
an impregnation step of impregnating the carbon fiber fabric with a thermosetting resin to obtain an impregnated carbon fiber fabric;
A lamination step of obtaining a laminate by arranging the impregnated carbon fiber fabric on both sides of a thermosetting resin foam having open cells;
and a compression heating step of compressing and heating the laminate,
A method for producing a carbon fiber reinforced molded article, wherein the thermosetting resin in the impregnation step contains phenolic resin and polyvinyl butyral diluted with alcohol.

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