JP2003105109A - Method for manufacturing molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing an excellent molded article that has few defects on the surface of the molded article as well as in the inside, particularly so when a sandwiched panel or the like is molded with a low pressure, and that has high strength, heat resistance, tenacity, and impact resistance. SOLUTION: According to this method for manufacturing a molded article, at least a structural unit (A): a reinforced fiber, and a structural unit (B): a heat-curable resin that increases its viscosity >=5 times at 70 deg.C when exposed to UV irradiation at a wave length of 365 nm for 300 seconds in an illuminance of 4.0 mW/cm<2> , are used, and at least the structural unit (B) is irradiated with UV rays and then subjected to press molding.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a molded article made of a fiber-reinforced composite material. In particular, the present invention relates to a molded product having few holes and dents on the surface of the molded product and having excellent surface smoothness.

[0002]

2. Description of the Related Art A fiber-reinforced composite material composed of a reinforcing fiber and a matrix resin has excellent mechanical properties despite its light weight, and therefore is widely used for transporting vehicles such as aircraft and automobiles, sports applications, and industrial applications. It is required to reduce internal defects in order to sufficiently bring out the mechanical properties and durability of the fiber-reinforced composite material, and to reduce surface defects in order to improve the design.

As a conventional technique for reducing defects such as surface pits and dents in a fiber-reinforced composite material molded body, a method of protecting the surface of a laminate with a gel coat or a film adhesive has been widely used. For example, JP-A-6-344451
In the publication, a surface layer made of a thermosetting resin is formed on the surface of a molded article body made of a continuous fiber reinforced thermosetting resin,
A molded product obtained by integrally curing with a thermosetting resin of a molded product body is disclosed. In addition, JP 2001-1
Japanese Patent No. 05441 discloses a molded article including a gel coat resin layer, an intermediate layer made of a radical curable resin containing a filler and the like in a specific range and having a tensile elongation in order from the surface layer, and a fiber reinforced plastic layer. However, from the viewpoints of material weight reduction, material cost reduction, and molding cost reduction, it is required to obtain a molded product that is smooth and has no surface defects without using such a surface protective material.

Therefore, a technique for improving the surface smoothness of the molded product by adding an additive to the inside of the resin is also under study.
For example, in JP-A-2001-123002, in a sheet molding compound (SMC) or bulk molding compound (BMC) in which an unsaturated polyester resin is a main component of a matrix resin and a glass fiber is a reinforcing fiber, expandable fine particles are added to the resin. A technique for improving the surface smoothness of a molded body by adding and expanding the molded body resin from the inside during molding is disclosed. However, with this technique, defects are contained inside the molded body, and it is not suitable for applications requiring higher performance.

A technique relating to prepreg is disclosed in Japanese Patent Laid-Open No.
JP-A-8-19332 describes a method in which an epoxy resin and an acrylate monomer are used in combination, and after impregnating the reinforcing fiber, the acrylate monomer is polymerized by electron beam irradiation to reduce the tackiness of the prepreg. Further, in JP-A-58-8732 and JP-A-9-3158, a method is used in which a compound that generates radicals by ultraviolet rays is used in combination with an epoxy resin, and polymerization is promoted by irradiation of ultraviolet rays to reduce tackiness of the prepreg. Is listed. However, neither is intended to improve the surface smoothness of the molded product, and the surface condition of the heated molded product is not disclosed. Moreover, the degree of resin viscosity change due to irradiation is not shown. In JP-A-3-103446, an epoxy resin and a vinyl compound are blended in order to obtain a prepreg excellent in workability as a result of not using a solvent at the time of producing a prepreg, which is advantageous in developing mechanical properties of a molded article. A method of advancing either a curing reaction of an epoxy resin or a radical polymerization reaction of a vinyl compound after impregnating a reinforcing fiber with a resin is disclosed. However, this is also not intended to improve the surface smoothness of the molded product, and the surface condition of the heated molded product is not disclosed.

[0006]

In any of the techniques disclosed in the above-mentioned known examples, whether surface smoothness is not sufficiently improved,
The suppression of defects inside the molded product was insufficient. Alternatively, since the surface protective material is externally applied, the weight of the molded product is increased. That is, it has been an extremely difficult task to obtain a molded product having excellent surface smoothness and having few voids inside the molded product without using a gel coat or a surface protective film so as not to increase the weight.

In view of the background of such prior art, the present invention is
Excellent molding with high strength, heat resistance, toughness and impact resistance in addition to low surface smoothness and internal defects even when low pressure molding of molded products with low surface and internal defects, especially sandwich panels. It is intended to provide a method for producing a molded body capable of providing a body.

[0008]

The present invention employs the following means in order to solve the above problems. That is, the method for producing a molded article of the present invention is characterized in that at least the following constituent elements [A] and [B] are used and at least the constituent element [B] is irradiated with ultraviolet rays and then pressure-molded. is there.

[A] Reinforcing fiber [B] Illuminance at wavelength 365 nm of 4.0 mW / cm ² ,
Thermosetting resin whose viscosity at 70 ° C increases by a factor of 5 or more by UV irradiation with an exposure time of 300 seconds

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention has been earnestly studied for the above-mentioned problems, that is, an excellent molded product having high strength, heat resistance, toughness, and impact resistance in addition to having less surface smoothness and internal defects, and before molding. , Irradiating the constituent materials with a certain range of ultraviolet rays,
When the viscoelasticity of the resin was changed by a certain amount or more and then pressure molding was performed, it was clarified that these problems can be solved at once.

First, the manufacturing method of the present invention comprises the following components. [A] Reinforcing fiber [B] Illuminance at wavelength 365 nm of 4.0 mW / cm ² ,
Thermosetting resin whose viscosity at 70 ° C. is increased by 5 times or more by UV irradiation with an exposure time of 300 seconds Such a constituent element [A], the reinforcing fiber is a glass fiber, a carbon fiber, an aramid fiber, a boron fiber, Alumina fiber, silicon carbide fiber, etc. are used. Two or more kinds of these fibers may be mixed and used. In order to obtain a lighter and more durable molded product, it is particularly preferable to use carbon fiber or graphite fiber.

The form and arrangement of the reinforcing fibers are not limited, and for example, long fibers aligned in one direction, tows, woven fabrics (cloths), mats, knits, braids, chopped yarns (short fibers), etc. may be used.

The use of a substantially non-twisted flat carbon fiber multifilament yarn composed of a large number of carbon fibers as a reinforcing fiber makes it difficult for the surface resin to sink into the inside of the molded article, so that molding after curing It is preferable because it improves the surface smoothness of the body.

Here, "substantially no twist" means that there is no twist of 1 turn or more per 1 m of the yarn length. In particular, the multifilament yarn has substantially no twist, and the bundling property is a hook drop value, preferably 100 to 1000.
It is preferable to use a multifilament yarn having a diameter of 10 mm, more preferably 100 to 500 mm, from the viewpoint of improving the smoothness of the surface of the molded body because the movement of the fiber is reduced and the flat state of the multifilament yarn is easily maintained.

Here, the hook drop value means a temperature of 23.
A carbon fiber bundle is suspended vertically in an atmosphere of 60 ° C. and a humidity of 60%, and 20 to 30 mm at the top and bottom of a stainless wire having a diameter of 1 mm and a length of about 100 mm is bent,
Hang a 12g weight on the bottom and hook the top on the fiber bundle,
It is a value represented by the distance of weight drop after 30 minutes. If there is twist or twist, this value becomes smaller.

When the reinforcing fiber is a carbon fiber yarn, generally, the carbon fiber yarn is one in which the sizing agent is entangled with each other or the sizing agent is adhered to control the focusing property. Thread hook drop value is 1
If it is less than 00 mm, the sizing property is too strong and the spread of the carbon fibers during molding is restricted, so it is difficult to obtain a molded product with a smooth surface, and the resin impregnation property into the carbon fibers tends to be poor. However, as a result, there arises a problem that voids are likely to occur inside the molded body. On the contrary,
When the hook drop value of the carbon fiber yarn exceeds 1000 mm, the carbon fiber yarn has poor converging property, fluffing is likely to occur, weaving property is deteriorated, and strength of the composite material is reduced. .

The shape of the surface of the reinforcing fiber is also a factor that affects the surface smoothness of the molded product. That is, the surface area ratio measured by the method described later with an atomic force microscope (AFM) is preferably 1.00 to 1.
It has been found that it is preferable to use a carbon fiber in the range of 10, and more preferably in the range of 1.00 to 1.05 in order to obtain a molded product having good surface smoothness.

The surface area ratio is the ratio of the actual surface area of the carbon fiber surface to the projected area and represents the degree of roughness of the fiber surface. The closer the surface area ratio is to 1, the closer the cross section is to a perfect circle. Is shown. That is, it becomes 1.00 when there is no unevenness on the carbon fiber surface. The smoother the fiber surface, the easier resin will enter between the fibers during molding, and as a result the individual fibers will be more easily dispersed.

If the surface area ratio exceeds 1.10, the surface smoothness tends to be insufficient.

The surface area ratio of carbon fibers is measured as follows. That is, the carbon fiber to be used for measurement is fixed to the sample table, and NanoScope III manufactured by Digital Instruments is used,
An image of the three-dimensional surface shape is obtained under the following conditions.・ Probe: Si cantilever integrated probe (Olympus Optical Industry Co., Ltd. OMCL-AC120TS) ・ Measurement environment: 25 ° C in atmosphere ・ Observation mode: tapping mode ・ Scanning speed: 0.3-0.4 Hz ・ Scanning range: 2 .5 μm × 2.5 μm ・ Number of pixels: 512 × 512 For the entire image obtained, the software (NanoScope III version 4.22r2, primary Flatten)
Data is processed using a filter, a Lowpass filter, and a third-order Plane Fit filter) to calculate the actual surface area and projected area. The projected area is calculated by calculating the projected area on the quadric surface approximated in consideration of the curvature of the fiber cross-sectional area, and the surface area ratio is calculated by the following formula.

Surface area ratio = actual surface area / projected area The same measurement is performed twice, and the average value is taken as the surface area ratio of the carbon fiber.

In the present invention, the constituent element [B] is an illuminance of 4.0 mW / cm ^{2 at} a wavelength of 365 nm and an exposure time of 3
It is a thermosetting resin whose viscosity at 70 ° C. increases five times or more by irradiation with ultraviolet rays for 00 seconds.

In the present invention, a resin whose viscosity increases by irradiation with ultraviolet rays is used. That is, by using a thermosetting resin whose viscosity at 70 ° C. increases by 5 times or more by irradiation with ultraviolet rays before heat-press molding, it is possible to secure an appropriate resin layer on the surface of the molded article, and to obtain high surface smoothness. A molded body can be obtained.

If the increase in viscosity is less than 5 times, the degree of thickening is low, the resin flow cannot be controlled, and a molded product having high surface smoothness cannot be obtained. In that sense, it is preferable to use a resin whose resin viscosity at 70 ° C. after ultraviolet irradiation is preferably 20 Pa · sec or more, and more preferably 50 Pa · sec or more.

Here, the thermosetting resin is not particularly limited as long as it is a resin which is cured by heat or energy from the outside such as light or electron beam to at least partially form a three-dimensional cured product. Preferred thermosetting resins include epoxy resins, cyanate resins, benzoxazine resins, maleimide resins, polyimide resins, vinyl ester resins, unsaturated polyester resins, phenol resins and the like.

As the thermosetting resin of the constituent element [B],
In addition to the epoxy resin described below, a cyanate resin is also preferably used. Cyanate resin is a cyanate ester of polyhydric phenol typified by bisphenol and phenol novolac. Generally, it has better heat resistance and lower water absorption than an epoxy resin, and is therefore preferable when the characteristics at high temperature of water absorption are important.

Benzoxazine resins are also preferred as component [B]. The benzoxazine resin is a resin having an oxazine ring synthesized from phenols, aldehydes and amines. Since it cures by ring-opening polymerization, no condensation water is generated and voids are less likely to occur in the molded product. If bisphenol is selected as the phenol, it becomes bifunctional. Bisphenol A as the raw material bisphenol,
Various structures such as bisphenol F, bisphenol S, biphenyl, dihydroxybenzophenone and diphenylfluorene can be used. Also, naphthol,
Polycyclic phenols such as naphthodiol can also be used as a raw material.

In addition, as the thermosetting resin of the constituent [B], a maleimide resin having an average of two or more maleimide groups in the molecule is also preferable because it has good heat resistance. In addition, a polyimide resin, a resin having a vinyl group or an allyl group, for example, a vinyl ester resin or an unsaturated polyester resin can be used as the constituent element [B]. Also,
Phenolic resin has high flame retardancy and is preferable as an interior material or a building material, and thus is used as a component of the constituent element [B] within a range not impairing the surface smoothness of the molded body.

Various modifiers can be added to the thermosetting resin of the constituent element [B] in order to improve the viscoelasticity of the uncured resin and the rigidity and toughness of the cured resin. Specifically, one or more additives selected from solid rubber, liquid rubber, thermoplastic resin elastomer, thermoplastic resin, organic or inorganic particles, short fibers and the like are preferably used. In particular, addition of acrylonitrile-butadiene copolymer, which is a random copolymer of butadiene and acrylonitrile, which is a solid rubber, is preferable from the viewpoint of compatibility with an epoxy resin, and a reactive rubber having a function of controlling resin flow during molding. It is more preferable because it exists.

It is also preferable to add inorganic particles as a modifier of the constituent element [B]. As such inorganic particles,
Talc, aluminum silicate, particulate silica, calcium carbonate, mica, montmorillonite, smectite,
Carbon black, silicon carbide, hydrated alumina, etc. are used. These inorganic particles have a large effect of rheology control, that is, thickening and thixotropy imparting effect. Among them, fine particle silica is known to have a large thixotropic effect when added to a resin composition, but not only that, but also reduces the temperature dependence of the viscoelastic function of the resin composition, It is preferable that the handling property does not easily deteriorate even if the environmental temperature fluctuates, and the surface smoothness of the molded product, which is a cured product, is improved. Such fine particle silica,
For example, those having an average primary particle size in the range of 5 to 40 nm are preferably used from the viewpoint of providing a sufficient thickening effect, and are commercially available under the trademark Aerosil (manufactured by Nippon Aerosil Co., Ltd.). Can be used.

As the fine particle silica, those whose surface is covered with silanol groups are preferably used.
The hydrophobic fine particle silica in which hydrogen of the silanol group is replaced with a methyl group, an octyl group, dimethylsiloxane, etc. is represented by the thickening effect of the resin, the thixotropic stability, and the water resistance and compression strength of the molded product. It is particularly preferably used from the viewpoint of improving mechanical properties.

When inorganic particles are added as a modifier, it is preferably added in a range of 0.8 to 8% by weight based on the entire resin composition. If it is less than 0.8% by weight, it is difficult to obtain the effect of improving the surface smoothness of the molded body. On the other hand, if it exceeds 8% by weight, the resin viscosity becomes too high and it becomes difficult to impregnate the reinforcing fibers. A more preferable addition amount is in the range of 0.8 to 5% by weight, and a further preferable range is 0.8 to 3% by weight.

It is also preferable to add a known thermoplastic resin as a modifier to the thermosetting resin. Specifically, polysulfone, polyether sulfone, polyether imide,
Polyvinyl formal, polyvinyl butyral, polyethylene oxide, copolymer nylon, etc. are used.

In addition to the above-mentioned additives, the thermosetting resin of the present invention contains additives such as polymer compounds, reactive diluents, chain extenders, antioxidants and organic particles. You can

Further, in the present invention, after the surface material comprising at least the constituent elements [A] and [B] is made into a sandwich structure constituted by sandwiching the constituent element [C], the surface material is irradiated with ultraviolet rays. It is preferable.

[C] There are various methods for producing a core material fiber-reinforced composite material molded body. As one of the preferred manufacturing methods of the present invention, resin injection molding (RTM
Method) can be used. The RTM method is a method of injecting a liquid thermosetting resin into a reinforcing fiber base material placed in a mold and curing the resin to obtain a fiber-reinforced composite material molded body. Among them, the vacuum RTM method of depressurizing the cavity of the mold and injecting the resin by utilizing the pressure difference between the inside and the outside is preferable. further,
By sandwiching the core material between the sheets of the reinforcing fiber base in the RTM method, a molded article having a sandwich structure with high rigidity can be obtained, which is preferable as the molded article of the present invention.

As the reinforcing fiber base material, a woven fabric made of fibers, a braid or the like may be used as it is, and the woven fabric or the like is laminated and shaped, and the form is fixed by a means such as a binder or a stitch to form a preform. You may use what was done.

The mold may be a closed mold made of a rigid body, or a method of using a rigid one-sided mold and a flexible film (bag material). In the latter case, the reinforcing fiber substrate is placed between the rigid one-sided type and the flexible film.

As the rigid mold material, various existing materials such as metal (steel, aluminum, etc.), FRP, wood, gypsum, etc. are used. As the flexible film, a film made of nylon, fluororesin, silicone resin or the like is used.

When a rigid closed mold is used, it is usually practiced to pressurize and close the mold, and pressurize and inject the liquid resin composition. At this time, a suction port may be provided separately from the injection port and connected to a vacuum pump for suction. Suction, and without using special pressurizing means,
It is also possible to inject the liquid resin only at atmospheric pressure.

When a rigid one-sided type and a flexible film are used, the injection is usually performed by suction and atmospheric pressure. In order to achieve good resin impregnation by injection at atmospheric pressure, it is effective to use a resin diffusion medium as shown in US Pat. No. 4,902,215.

It is also possible to install a foam core, a honeycomb core, metal parts, etc. in the mold in addition to the reinforcing fiber base material to obtain a composite material integrated with these. In particular, a sandwich structure obtained by arranging and molding a reinforcing fiber base material on both sides of a foam core is lightweight and has large bending rigidity, and is therefore useful as a structural material or an outer plate material.

After the resin injection is completed, curing is performed by using a suitable heating means. The temperature at this time is selected according to the level of heat resistance required for the product because it correlates with the glass transition temperature of the resin of the final molded body, that is, the heat resistance of the molded body, but is preferably 60 to 180 ° C. . If the curing temperature is set to an unnecessarily high temperature, it will take longer to raise or lower the temperature, or the mold, heat medium, and auxiliary materials used will become expensive, so high heat resistance is not required. As long as it is 60 to 150 ° C., more preferably 60 to 100 ° C.
C is preferred. The molding time is usually 10 minutes to 6 hours, and curing is performed at least until the mold can be released. If necessary, post-curing after demolding is also preferable because it enhances the heat resistance of the molded body.

In the present invention, the constituent [A] preferably contains at least carbon fiber and / or graphite fiber.

It is preferable to use carbon fiber among various reinforcing fibers in order to obtain a molded product having high elastic modulus and high strength. However, other reinforcing fibers such as glass fiber, aramid fiber, metal fiber, etc. may be used. In particular, since glass fiber transmits ultraviolet rays, ultraviolet rays reach not only the surface but also the internal resin even after the reinforcing fiber is impregnated with the resin, and thus the surface smoothness improving effect is easily obtained, which is preferable for the present invention. . As a method of combining different kinds of reinforcing fibers, changing the combination of the warp and the weft of the woven fabric, for example, one of which is carbon fiber and the other is glass fiber, or a combination of carbon fiber woven fabric and other reinforced fiber woven fabric or mat, etc. There are methods such as stacking.

Further, in the present invention, the number of filaments of the multifilament yarn as the constituent element [A] is preferably 2500 to 25000.

The number of filaments in one fiber bundle is 250
If the number of fibers is less than 0, the fiber arrangement is likely to meander and cause surface irregularities. Further, if the number exceeds 30,000, resin impregnation does not occur sufficiently. More preferably 2800-250
The range is 00. Especially the number of filaments 5000-2
The number of 5000 is preferable from the viewpoint of improving the surface smoothness of the molded body.

In the present invention, the component [A] is
It is preferable that the woven structure has a structure selected from plain weave, twill weave, entangled weave, and satin weave. .

It is preferable to use a woven fabric as the reinforcing fiber because it has a better surface shaping property than the unidirectional reinforcing material and can be laid along the curved surface type without wrinkles. As the woven structure, woven fabrics such as plain weave, twill weave, entangled weave, and satin weave are preferable. Particularly, it is suitable because it is easy to form a molded body having a plain weave structure.

In the present invention, the woven structure comprises carbon fiber multifilament yarn as a woven yarn and has a fiber areal weight of 10
It is preferably from 0 to 320 g / m ² .

It is possible to use a woven fabric in which the carbon fiber multifilament yarn is flat, the yarn thickness is 0.05 to 0.2 mm, the yarn width / thread thickness ratio is 30 or more, and the fabric weight is 100 to 320 g / m ^2. It is preferable because it suppresses crimp to a small level and improves the surface smoothness of the molded body. By using such a flat woven yarn, a woven fabric having a higher fiber density than an ordinary woven fabric can be obtained, and the surface smoothness of the molded body is also improved, which is preferable. It is preferable that the thickness of one layer of the resin-impregnated sheet material is thin because unevenness due to bending of the woven yarn does not occur so much and high strength is exhibited from the viewpoint of improving the surface smoothness of the molded body. A woven fabric using the above flat carbon fiber multifilament yarn can be produced by the method described in JP-A-7-300339.

In the present invention, the cover factor of the woven structure is preferably 95% or more.

In the reinforcing fiber woven fabric, it is preferable that the gaps formed between the weaving yarns are crushed and small. When the cover factor, which is the area occupied by the portion where the reinforcing fibers are present in the constant evaluation area, is 95% or more, a molded product with particularly good surface smoothness can be obtained, and a molded product with few internal defects can be easily obtained.
If the cover factor is insufficient, pits are likely to occur on the surface of the molded product and voids inside. According to the present invention, the range of the cover factor is preferably 96% or more, more preferably 97.5% or more.

The cover factor is preferably measured, for example, as follows. That is, first, an actual condition microscope, for example, actual condition microscope SMZ-10-1 manufactured by Nikon Corporation.
Photograph the textile surface using. As a result, a high-contrast image is obtained in which the fiber-occupied portion is black and the resin-only portion without fibers is relatively white. The amount of light is set within the range that does not cause halation. The obtained photograph is photographed with a CCD (charge coupled device) camera, the photographed image is converted into digital data representing light and shade of black and white and stored in a memory, which is analyzed by an image processing device, and the total area S1 and The cover factor (Cf) of the following equation is calculated from the area S2 of the white portion (resin portion). The same thing is done at 10 points, and the simple average value is used as the cover factor.

Cf = [(S1−S2) / S1] × 100 In the present invention, it is preferable that the constituent [B] contains at least an epoxy resin and a resin component having a radical-polymerizable unsaturated bond. .

By containing at least an epoxy resin and a resin component having a radical-polymerizable unsaturated bond as the constituent element [B], the resin viscosity can be appropriately increased by irradiation with ultraviolet rays before molding, and in the heat curing. It is preferable because the resin fluidity can be easily controlled and a molded product having excellent surface smoothness can be easily obtained.

Preferred examples of the epoxy resin as the component [B] include amines, phenols, and epoxy resins having a compound having a carbon-carbon double bond as a precursor. Specifically, a glycidyl ether type epoxy resin having phenol as a precursor is preferable. Bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin,
Phenol novolac type epoxy resin, cresol novolac type epoxy resin, and resorcinol type epoxy resin are used.

Liquid bisphenol A type epoxy resin,
The bisphenol F type epoxy resin and the resorcinol type epoxy resin are preferably mixed with other epoxy resins and additives for adjusting the viscosity of the composition.

The solid bisphenol A type epoxy resin gives a structure having a lower crosslink density than that of the liquid bisphenol A type epoxy resin, so that the heat resistance is lowered, but it is preferably blended appropriately to obtain a structure having higher toughness. Used.

The epoxy resin having a naphthalene skeleton is
It is preferable because it gives a cured resin having low water absorption and high heat resistance. Further, a biphenyl type epoxy resin, a dicyclopentadiene type epoxy resin, and a diphenylfluorene type epoxy resin are also suitably used because they give a cured resin having a low water absorption rate.

These epoxy resins may be used singly or may be appropriately blended and used. It is preferable to mix at least a bifunctional solid epoxy resin and a trifunctional or higher functional epoxy resin, since the resin has both fluidity and heat resistance after curing. In particular, at least one epoxy resin that is liquid at room temperature and one epoxy resin that is solid at room temperature
Blending with seeds controls the resin fluidity during molding,
It is preferable because a molded product having a smooth surface can be easily obtained.

A compound of a phenol novolac type epoxy resin or a cresol novolac type epoxy resin is also preferable because it gives a resin having high heat resistance and water resistance and also has a fluidity control at the time of molding so as to enhance the surface smoothness of the molded body.

Further, tetraglycidyldiaminodiphenylmethane as an epoxy resin containing amines as a precursor,
Various isomers of triglycidyl p-aminophenol and triglycidyl aminocresol can be mentioned. It is preferable because a molded article having high heat resistance can be easily obtained and the gelation time during molding can be shortened.

As the curing agent for the epoxy resin, any compound having an active group capable of reacting with the epoxy group can be used. A compound having an amino group, an acid anhydride group or an azido group is preferable. More specifically, for example, dicyandiamide, various isomers of diaminodiphenylmethane and diaminodiphenylsulfone, aminobenzoic acid esters, various acid anhydrides, phenol novolac resins, cresol novolac resins, polyphenol compounds, imidazole derivatives, aliphatic amines, Examples include tetramethylguanidine, thiourea-added amine, carboxylic acid anhydride such as methylhexahydrophthalic anhydride, carboxylic acid hydrazide, carboxylic acid amide, polymercaptan, and Lewis acid complex such as boron trifluoride ethylamine complex. To be When an aromatic diamine is used as a curing agent, an epoxy resin cured product having good heat resistance can be obtained. Especially, various isomers of diaminodiphenyl sulfone are most suitable for obtaining a cured product having good heat resistance. The addition amount is preferably stoichiometrically equivalent, but depending on the case, for example, the equivalence ratio is 0.7 to 0.8.
It is preferable to use an auxiliary resin because a high elastic modulus resin can be obtained.
These curing agents may be used alone or in combination. Further, it is preferable to use a combination of dicyandiamide and a urea compound, for example, 3,4-dichlorophenyl-1,1-dimethylurea, or an imidazole as a curing agent, because high heat resistance and water resistance can be obtained while curing at a relatively low temperature. Curing with an acid anhydride is preferable because it gives a cured product having a lower water absorption rate than curing with an amine compound. In addition, it is preferable to use a latent product of these curing agents, for example, a microencapsulated product, because the storage stability of the prepreg, particularly the tackiness and the drapability, are unlikely to change even if left at room temperature.

Further, the epoxy resin and the curing agent, or a product obtained by pre-reacting a part of them may be blended in the composition. This method may be effective in adjusting viscosity and improving storage stability.

As the thermosetting resin of the component [B],
It is preferable to contain a resin component having a radically polymerizable unsaturated bond, because the resin viscosity can be appropriately increased by irradiation with ultraviolet rays before molding, and a molded product having excellent surface smoothness can be easily obtained by subsequent pressure molding. . In particular, a low molecular weight compound or a high molecular weight compound containing a double bond or a triple bond in the molecule is preferable, and the effect of improving the surface smoothness is greatest when used in combination with the epoxy resin.

Specific examples of the resin component having a radical-polymerizable unsaturated bond are preferably unsaturated polyester, epoxy (meth) acrylate and urethane (meth).
An acrylate or a mixture thereof is dissolved in a polymerizable unsaturated monomer, or a curing accelerator or a curing agent is added, if necessary. These may be used alone or in combination of two or more.

The unsaturated polyester used in the present invention is obtained by a condensation reaction of a dibasic acid containing an α, β-unsaturated dibasic acid with a polyhydric alcohol, and optionally a dicyclopentadiene compound. is there. The molecular weight is preferably in the range of 500 to 5000.

As the α, β-unsaturated dibasic acid used for preparing the unsaturated polyester, maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride and the like can be used. As the saturated dibasic acid, phthalic acid, phthalic anhydride, halogenated phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic acid, hexahydrophthalic anhydride, hexahydroterephthalic acid, Hexahydroisophthalic acid, succinic acid, malonic acid, glutaric acid, adipic acid, sebacic acid, 1,12-
Dodecane diacid, 2,6-naphthalenedicarboxylic acid, 2,
7-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic anhydride,
4,4'-biphenyldicarboxylic acid, dialkyl esters thereof, or the like can be used. These may be used alone or in combination of two or more.

Examples of the polyhydric alcohols used for preparing the unsaturated polyester include, for example, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol.
, Dipropylene glycol, polypropylene glycol
2-methyl-1,3-propanediol, 1,3-
Butanediol, neopentyl glycol, hydrogenated bisphenol A, 1,4-butanediol, bisphenol
1,2,3,4-tetrahydroxybutane, glycerin, trimethylolpropane, 1,3-propanediol, 1,2-cyclohexane glycol, 1,3 −
Cyclohexane glycol, 1,4-cyclohexane glycol, 1,4-cyclohexane dimethanol, paraxylene glycol, bicyclohexyl-4,4'-diol, 2,6-decalin glycol , 2,7-decalin glycol and the like can be used. These may be used alone or in combination of two or more.

The epoxy (meth) acrylate used in the present invention means, for example, a bisphenol type epoxy resin alone, or a combination of a bisphenol type epoxy resin and a novolac type epoxy resin, a 1,6-naphthalene type epoxy resin. An epoxy resin such as di (meth) acrylate of an epoxy resin, whose average epoxy equivalent is preferably in the range of 150 to 450, and an unsaturated monobasic acid, and the presence of an esterification catalyst. It is obtained by reacting below.

As the above-mentioned bisphenol-type epoxy resins, only typical ones will be given. Di (meth) acrylate of bisphenol A type epoxy resin, di (meth) acrylate of hydrogenated bisphenol A type epoxy resin, Bisphenol A ethylene oxide addition type epoxy resin di (meth) acrylate, bisphenol A propylene oxide addition type epoxy resin di (meth) acrylate, bisphenol F type epoxy resin di (meth) acrylate, 1,6-naphthalene type epoxy resin Examples thereof include di (meth) acrylate.

As the above-mentioned novolac type epoxy resin, only representative ones are, for example, an epoxy resin obtained by the reaction of phenol novolac or cresol novolac with epichlorohydrin or methyl epichlorohydrin. . Further, only specific examples of the above-mentioned unsaturated monobasic acids are listed: acrylic acid, methacrylic acid, cinnamic acid, crotonic acid, sorbic acid, monomethylmalate, monopropylmalate, monobutylmer. Rate, or mono (2-ethylhexyl) malate.

These unsaturated monobasic acids may be used alone or in combination of two or more kinds. The reaction between the above-mentioned epoxy resin and unsaturated monobasic acid is preferably 60 to 14
It is carried out with an esterification catalyst at a temperature of 0 ° C., particularly preferably 80 to 120 ° C.

As the esterification catalyst, known and commonly used compounds can be used as they are, but if only representative ones are listed, triethylamine,
Various tertiary amines such as N, N-dimethylbenzylamine, N, N-dimethylaniline or diazabicyclooctane; or diethylamine hydrochloride.

The number average molecular weight of the epoxy (meth) acrylate is preferably 450 to 2,50.
0, particularly preferably in the range of 500 to 2,200 is suitable. When the molecular weight is less than 450, the resulting cured product becomes tacky or has poor strength properties. On the other hand, when it is greater than 2,500, the reactivity tends to be poor. become.

Polyols used for preparing the urethane (meth) acrylate include polypropylene oxide, polyethylene oxide, polytetramethylene glycol, bisphenol A ethylene oxide adducts, bisphenol A propylene oxide adducts and other polyether polyols, and polybutadiene diol. , Polyisoprene diol, polyester ether polyol, polyester polyol and the like are used.

The polyisocyanate used in preparing the urethane (meth) acrylate is
2,4-tolylene diisocyanate and its isomers or mixtures of isomers (hereinafter abbreviated as TDI), diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, dicyclohexyl methane diisocyanate, tolidine diisocyanate, Naphthalene diisocyanate, triphenylmethane triisocyanate, Bernock D-750, Chris Bonn NX (Dainippon Ink and Chemicals Co., Ltd. product), Desmodur L (Sumitomo Bayer Co., Ltd. product), Coronate L (Nippon Polyurethane Co., Ltd. product), Takenate D102
(Product of Takeda Pharmaceutical Company Limited), Isonate 143L
(Manufactured by Mitsubishi Chemical Corporation) and the like can be used, and they can be used alone or in combination of two or more. Of the above polyisocyanates, diisocyanates, especially TDI
Is preferably used.

The hydroxyl group-containing (meth) acrylic compound is preferably a hydroxyl group-containing (meth) acrylic acid ester, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-
Hydroxybutyl (meth) acrylate; Alcohol mono (meth) acrylates having two hydroxyl groups such as polyethylene glycol mono (meth) acrylate and polypropylene glycol mono (meth) acrylate;
Addition product of α-olefin epoxide and (meth) acrylic acid, addition product of carboxylic acid glycidyl ester and (meth) acrylic acid; di (meth) acrylate of tris (hydroxyethyl) isocyanuric acid, pentaerythritol tri (meth) acrylate, etc. Alcohol partial (meth) acrylates having three or more hydroxyl groups as described above are used.

In the production of the urethane (meth) acrylate of the present invention, a part of the hydroxyl group-containing (meth) acrylic compound is replaced with a compound such as a hydroxyl group-containing aryl ether or a higher alcohol which does not impair the effects of the present invention. You may.

As the hydroxyl group-containing aryl ether compound, known and conventional ones can be used. Among them, typical examples include ethylene glycol monoaryl ether,
Diethylene glycol monoaryl ether, triethylene glycol monoaryl ether, polyethylene glycol monoaryl ether, propylene glycol monoaryl ether, dipropylene glycol monoaryl ether, tripropylene glycol monoaryl ether, polypropylene glycol monoaryl ether, 1,2-butylene glycol Of polyhydric alcohols such as monoaryl ether, 1,3-butylene glycol monoaryl ether, hexylene glycol monoaryl ether, octylene glycol monoaryl ether, trimethylolpropane diaryl ether, glycerin diaryl ether, pentaerythritol triaryl ether, etc. Aryl ether compounds are used, and the hydroxyl group is 1 Aryl ether compounds having preferred.

As the higher alcohols, known and conventional ones can be used, but among them, representative ones include decyl alcohol, undecyl alcohol, lauryl alcohol, tridecyl alcohol, stearyl alcohol and the like.

As an example of the method for producing the urethane (meth) acrylate of the present invention, first, a polyether polyol and a polyisocyanate are added, preferably with a number average molecular weight of 500 to 30,000, particularly preferably 700 to 5,000.
To produce a urethane prepolymer containing a terminal isocyanate group, and then add a hydroxyl group-containing acrylic compound to the hydroxyl group of the prepolymer so that the hydroxyl groups are almost equivalent. To react.

As another method, first, a hydroxyl group-containing acrylic compound is reacted with a polyisocyanate, and then the obtained isocyanate group-containing compound is reacted with a polyether polyol, preferably with a number average molecular weight of 500.
~ 30000, more preferably 700-5000 urethane (meth) acrylates can be produced.

As the polymerizable unsaturated monomer, those generally used in unsaturated polyester resin compositions, vinyl ester resins and vinyl urethane resin compositions, such as styrene,
α-methylstyrene, chlorostyrene, dichlorostyrene, divinylbenzene, t-butylstyrene, vinyltoluene, vinyl acetate, diaryl phthalate, triaryl cyanurate, acrylic acid ester, methacrylic acid ester, etc .; ( (Meth) methyl acrylate, (meth)
Ethyl acrylate, n-butyl (meth) acrylate,
I-Butyl (meth) acrylate, t- (meth) acrylate
Butyl, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, stearyl (meth) acrylate, tridecyl (meth) acrylate, dicyclopenteni Roxyethyl (meth) acrylate, ethylene glycol monomethyl ether (meth) acrylate, ethylene glycol monoethyl ether (meth) acrylate, ethylene glycol monobutyl ether (meth) acrylate, ethylene glycol monohexyl ether (meth) acrylate, ethylene glycol mono-2- Ethylhexyl ether (meth) acrylate, diethylene glycol monomethyl ether (meth)
Acrylate, diethylene glycol monoethyl ether (meth) acrylate, diethylene glycol monobutyl ether (meth) acrylate, diethylene glycol monohexyl ether (meth) acrylate, diethylene glycol mono-2-ethylhexyl ether (meth) acrylate, dipropylene glycol monomethyl ether (meth) acrylate, di Propylene glycol monoethyl ether (meth) acrylate, dipropylene glycol monobutyl ether (meth) acrylate, dipropylene glycol monohexyl ether (meth) acrylate, dipropylene glycol mono-2-ethylhexyl ether (meth) acrylate, diethylene glycol di (meth) acrylate , Dipropylene glycol di (meta Acrylate, neopentyl glycolate
-Rudi (meth) acrylate, PTMG dimethacrylate, 1,3-butylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 2-hydroxy 1,3 dimethacryloxypropane 2,2-bis [4- (methacryloxyethoxy) phenyl] propane, 2,2-bis [4- (methacryloxydiethoxy) phenyl] propane, 2,2-bis [4- (methacryloxypolyethoxy) Phenyl] propane, tetraethylene glycol diacrylate, bisphenol A ethylene oxide modified (n = 2) diacrylate,
A polymerizable unsaturated monomer or unsaturated oligomer capable of crosslinking with a resin, such as isocyanuric acid ethylene oxide-modified (n = 3) diacrylate or pentaerythritol diacrylate monostearate, may be added. These polymerizable unsaturated monomers may be used alone or in combination of two or more kinds.

A radiation-polymerizable or copolymerizable raw material having a reactive functional group can be mixed in the resin composition. Such raw materials include carboxylic acid or sulfonic acid, acid anhydride, epoxy, hydroxy, phenol,
Raw materials having functional groups such as amines, unsaturated or other types of polymerizable or copolymerizable or graftable monomers or oligomers are mentioned. Such raw materials are fiber /
Helps improve or control the adhesion between resins and improve / control the interface / adhesion with other additives / fillers. Further, it is also useful for increasing the compatibility with a polymer added to the resin composition and / or added in a subsequent step such as a molding step or a mixing step. Particularly effective components to be blended for such purpose include (meth) acrylic acid or its anhydride, β-carboxyethyl acrylate or maleic anhydride and its derivatives, hydroxyalkyl acrylate, bisphenol A diepoxide half acrylate (epoxy). Functional acrylate), glycidyl (meth) acrylate derivative and the like are used.

In the present invention, the component [B] is
It is preferable to contain a component that generates radicals by ultraviolet rays.

In order to react the resin component having a radical-polymerizable unsaturated bond, it is preferable to add a photoinitiator and / or a photosensitizer which generate radicals upon irradiation with ultraviolet rays. In the absence of such molecules or combinations, irradiation with UV or visible light usually results in little or no polymerization. However, it does not have to be provided when the self-starting ability is provided. One or more photoinitiators and / or
Alternatively, a photosensitizer may be used. Examples of the radical system include α-hydroxyketone, 1-hydroxycyclohexylphenyl ketone, various benzoin ethers such as benzoin isobutyltere and benzoin ethyl ether, acetophenone, 2,2-diethoxyacetophenone, benzyl methyl ketal and benzophenone, and morphophone. Ketones containing phosphorus components, thioxanthone, 1,2
-Diketones, acylphosphine oxides, photoactive oximes, Michler's ketones, phosphine oxides such as bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, amine alcohols such as triethanolamine, eosin, titanocene derivatives, and A dye-sensitizing initiator component for visible light curing is used.

Cationic polymerizable systems can also be used. Examples of preferred photoinitiators for cationic systems include, for example, F
X512 (manufactured by 3M Company), Degacure K185
(Manufactured by Degussa), Cyracure UVI 6
Onium salts such as triallylsulfonium salts such as 974 and 6990 (manufactured by Union Carbide), and Irgacure 261 (Ciba Gei).
gy) and other transition metal complexes.

In the present invention, the component [B] is
By irradiating with UV light having an illuminance of 4.0 mW / cm ^{2 at} a wavelength of 365 nm and an exposure time of 300 seconds, the viscosity at 70 ° C. is increased five times or more, and the viscosity at 100 ° C. is 1000 Pa.
It is preferable that the thermosetting resin be in the range of seconds or less.

If the fluidity is excessively lost, it is difficult to form a smooth surface in pressure molding after irradiation with ultraviolet rays, so that the viscosity at 100 ° C. after irradiation with ultraviolet rays is preferably in the range of 1000 Pa · sec or less. More preferably, the resin viscosity at 100 ° C. after UV irradiation is 500 Pa · sec or less, and further 100 after UV irradiation.
The resin viscosity at ℃ is preferably 100 Pa · sec or less.

In the present invention, the content of the resin having a radical-polymerizable unsaturated bond is preferably in the range of 2 to 30% by weight of the constituent element [B].

If it is less than 2% by weight, the increase in resin viscosity due to the irradiation of ultraviolet rays is reduced, and it may be difficult to obtain the effect of improving the surface smoothness of the molded product. On the other hand, if it exceeds 30% by weight, the molding shrinkage becomes large, which may adversely affect the surface smoothness. In that sense, it is more preferably in the range of 3 to 20% by weight, further 5 to 15% by weight.
Is preferred.

Further, in the present invention, the content of the constituent element [B] is preferably in the range of 20 to 50% by weight based on the total weight of the constituent elements [A] + [B].

When the resin content is 20% by weight or less, surface pits on the molded product, resin fading, and defects in the molded product are likely to occur. Further, if the resin content exceeds 50% by weight, there is a concern that resin outflow tends to occur during molding.
Further, since the weight of the molded body is increased, the weight saving advantage of the fiber reinforced composite material is reduced. Particularly preferably, the resin content is in the range of 35 to 45% by weight.

In the present invention, it is preferable to use a foam core or a honeycomb core as the constituent element [C].

As the constituent element [C], it is preferable that it is lightweight, and a foam core is preferably used.
As the foam core, urethane resin core and phenol resin core are particularly preferable because they have excellent adhesiveness to the surface material,
Rohacell cores using an imide resin are preferable because they have excellent heat resistance. A honeycomb core is also preferable in that a structure having high rigidity and high strength can be formed. Nomex honeycomb core made of aramid paper impregnated with phenolic resin is particularly preferable because it is lightweight and has high rigidity and heat resistance, but aluminum honeycomb and glass fiber reinforced plastic (GFR
P) A honeycomb, a graphite honeycomb, a paper honeycomb or the like may be used.

In the present invention, a sheet material prepared by impregnating the gap of the constituent element [B] with the constituent element [B] is prepared,
It is preferable to irradiate ultraviolet rays and stack under pressure after stacking these layers.

The sheet material referred to here has a thickness of 20 mm or less, and may be a state in which the resin is completely impregnated even into the reinforcing fiber bundle, or a state in which it is partially impregnated. May be. It includes so-called prepreg, semi-preg and SMC. By irradiating the prepared sheet material with ultraviolet rays to increase the viscosity of at least the resin on the surface of the sheet material, it is possible to control the resin flow at the time of subsequent heat molding and obtain a molded article having high surface smoothness.

Forming a sandwich structure by sandwiching a sheet material as a surface material and a core material is preferable as a structural material or an outer plate material because a lightweight and high flexural rigidity molded article can be obtained.

When a prepreg is used as the sheet material,
It is common to use a wide prepreg in which a reinforcing fiber strand is impregnated with a resin in advance, but a narrow slit tape made of a prepreg or a bobbin that is made by impregnating the fibers aligned in one direction with the resin is wound. It is also preferable to use a strand prepreg or a yarn prepreg in which the resin is impregnated. When molding a sandwich structure, it is most preferable to use a prepreg in the form of a woven fabric because of its mechanical properties and ease of molding process.

The method for producing the prepreg is as follows, for example. That is, the resin composition is applied onto release paper using a reverse roll coater to produce a resin film. Next, two resin films are superposed on both sides of the carbon fiber, sandwiched between heated metal rolls, and pressed to impregnate the resin composition. After impregnation, peel off the release paper on one side from the prepreg, attach the polyethylene film to the surface of the peeled side, by winding the release paper on one side, the polyethylene film on the other side, by winding. It is to get a prepreg.

In the present invention, the pressure applied during the molding is
It is preferably 300 MPa or less.

To make a sandwich structure,
A plurality of prepregs made of a reinforcing fiber and a resin serving as a matrix are laminated on both sides of a core material, and the resin in the prepreg is cured and adhered to the core material. As a sandwich structure molding method, vacuum bag molding,
Although autoclave molding using a vacuum bag, press molding and the like can be mentioned, vacuum pressure molding is particularly preferable in the sense that a sandwich panel can be molded at a relatively low pressure.

According to the method for producing a molded article characterized by ultraviolet irradiation of the present invention, for example, a pressing force of 300 is applied as in this vacuum pressure molding.
In molding at MPa or less, the difference in surface smoothness between the case of molding without irradiation of ultraviolet rays and the case of irradiation with ultraviolet rays becomes particularly remarkable, and irradiation with ultraviolet rays gives a molded article with high surface smoothness. You can

[0106]

The present invention is described in detail below with reference to examples, but the present invention is not limited thereto.

In the examples, a sandwich structure was formed by using a woven prepreg obtained by impregnating carbon fibers with a resin in advance as the sheet material. (Ultraviolet irradiation condition) A high pressure mercury lamp was used for ultraviolet irradiation of the woven prepreg or the resin film. First, the illuminance was measured using an illuminometer (UIT-150 manufactured by Ushio Inc.), and irradiation with a high-pressure mercury lamp was performed so that the illuminance of 365 nm ultraviolet rays on the surface of the woven prepreg or the resin film was 4.0 mW / cm ^2. Set the position. Next, the woven prepreg or the resin film was fixed at a predetermined position, and UV irradiation was performed for 300 seconds at 23 ° C. in an atmospheric air atmosphere. (Resin Viscosity Measuring Conditions) The resin viscosity was measured using a rheometrics viscoelasticity measuring device ARES. The measurement uses a parallel plate having a radius of 20 mm, the distance between the plates is 1.0 mm, the measurement starting temperature is 25 ° C., and the heating rate is 1.5 ° C. /
Min, the complex viscosity η * at 70 ° C. or 100 ° C. was measured by measuring the temperature rise to 70 ° C. or higher under the condition of the measurement frequency of 0.5 Hz, and defined as the resin viscosity. (Molding and Surface Smoothness, Internal Void Evaluation) The surface smoothness of the molded product was evaluated by molding a panel by the following method and using a surface roughness meter. The laminated structure of the sandwich structure using the woven prepreg has two layers of (± 45 °) / (± 45 °) in the upper and lower sides so that the upper and lower sides are symmetrical with respect to the core material.
It was a symmetrical stack of plies. At that time, first, place the laminated body of the core material and the prepreg on the aluminum plate subjected to the surface release treatment, cover the nylon bag with the laminated body on the aluminum tool plate, seal the periphery, and vacuum the inside of the bag. Kept at. In this state, the temperature was raised and molding was performed. The molding conditions are heating under a pressure of ² kg / cm ^{2 at} a temperature rising rate of 1.5 ° C./min and holding at 110 ° C. for 2 hours. In addition,
The core material used in these tests is Nomex Honeycomb SAH1 / 8-3.0 (manufactured by Showa Aircraft Co., Ltd .:
SAH1 / 8-3.0, thickness 12.7 mm) was used.

The surface smoothness on the tool plate side of the molded product was quantified by a surface roughness meter Surftest 301 manufactured by Mitutoyo Corporation. A length of 9 cm was evaluated with a stylus, and the difference in height between the highest point and the lowest point in the surface roughness curve between them was determined. The cutoff value for the height of the baseline was 8 mm. Do this for any location on the compact
It was carried out once and the average value was obtained.

The void content in the skin material of the molded product was quantified by the area method. After cutting a molded product having a length of about 26 cm and a width of about 19 cm molded under the above-mentioned laminated structure and curing conditions in the width direction, the cross section is polished, and a micrograph is taken at a magnification of 25 times, which is the lower surface of the tool surface. The index was a value obtained by dividing the void area in the constant cross section of the skin material by the constant cross sectional area of the skin material. At this time, a range of 25 mm was selected in the length direction so as to include a portion having the most voids in the entire field of view observed in the cross section, and the void area was calculated.

Example 1 60 parts by weight of bisphenol A type liquid epoxy (manufactured by Japan Epoxy Resin Co., Ltd., average epoxy equivalent 184-194: Ep828), bisphenol A type solid epoxy (manufactured by Japan Epoxy Resin Co., Ltd., average) Epoxy equivalent 450-500: Ep10
01) 20 parts by weight, bisphenol A type solid epoxy (manufactured by Japan Epoxy Resin Co., Ltd., average epoxy equivalent 875-975: Ep1004) 20 parts by weight, and 3 parts by weight of polyvinyl formal (Vinilec K, manufactured by Chisso Co., Ltd.) are added. The mixture was heated and kneaded, and polyvinyl formal was dissolved in the epoxy resin. After the temperature was lowered to 60 ° C., 10 parts of urethane acrylate (M-1100 manufactured by Toagosei Co., Ltd.) was added.
A part by weight was added and the mixture was kneaded for 30 minutes. Further, 5 parts of dicyandiamide (DICY7, manufactured by Japan Epoxy Resin Co., Ltd.) as a curing agent for the epoxy resin, and 3-part as a curing accelerator.
4 parts of (3,4-dichlorophenyl) -1,1-dimethylurea (DCMU99, Hodogaya Chemical Co., Ltd.) and 2,2-dimethoxyacetophenone (Ciba Specialty Chemicals Co., Ltd .: Irgac) as a photoinitiator
1 part by weight of ure651) was added and stirred for 30 minutes to prepare an epoxy resin composition.

The resin composition was coated on release paper at 70 ° C. to prepare a resin film having a resin areal weight of 66 g / m ² . This resin film was set in a prepreg machine and the strand tensile strength was 4.9 GPa and the tensile elastic modulus was 23.
Carbon fiber T700SC-12K manufactured by Toray Industries, Inc. having 0 GPa and a tensile elongation at break of 2.1% (fiber number 12000, fineness 7200 denier, hook drop value 180 mm, A
Carbon fiber plain weave fabric with a surface area ratio of 1.04 measured by FM (cover factor 96.2%, basis weight 190 g /
m ² , thread thickness 0.11 mm, thread width / thread thickness ratio 70.2)
Resin impregnation was carried out from both sides to obtain a prepreg. The resin impregnation temperature at this time was 100 ° C. The resin content of the prepreg was 41% by weight.

The prepared prepreg was irradiated with ultraviolet rays under the above conditions. At this time, the resin film was also irradiated with ultraviolet rays under the same irradiation conditions, and the resin viscosity before and after irradiation was measured. The viscosity before irradiation was 12 Pa · sec (70 ° C), while the viscosity after irradiation increased to 110 Pa · sec (70 ° C). The viscosity at 100 ° C. was 47 Pa · sec.

A sandwich structure was formed under the above conditions using the prepreg and the honeycomb core, and the surface roughness on the tool surface side was measured to be 16.4 μm, which was excellent. The cross section of the sandwich structure was polished with sandpaper and alumina powder, and an optical microscope photograph was taken.
From this photograph, it was found that the void content in the skin panel on the tool surface side was as low as 0.19%.

Comparative Example 1 A resin composition, a prepreg and a sandwich structure were obtained in the same manner as in Example 1 except that urethane acrylate and 2,2-dimethoxyacetophenone were removed from the resin composition of Example 1. The resin viscosity before and after irradiation with ultraviolet rays did not change, and was 12 Pa · sec (70 ° C.). When the surface roughness of the molded body was measured, it was 49.4 μm.
And was inferior to Example 1. The void content in the tool side skin panel was as high as 1.51%.

Example 2 A resin composition, a prepreg and a sandwich structure were obtained in the same manner as in Example 1 except that the amount of urethane acrylate added was reduced to 5 parts by weight from the resin composition of Example 1. . Resin viscosity before UV irradiation is 1
It was 3 Pa · sec (70 ° C.), while the viscosity after irradiation was 6
It had increased to 0 Pa · sec (70 ° C). The viscosity at 100 ° C. was 24 Pa · sec. When the surface roughness of the molded body was measured, it was 25.8 μm. The void content in the tool side skin panel was 0.49%.

(Comparative Example 2) From the resin composition of Example 1,
A resin composition, a prepreg and a sandwich structure were obtained in the same manner as in Example 1 except that 2-dimethoxyacetophenone was excluded. Resin viscosity before and after UV irradiation is 12Pa
It did not change since it was second (70 ° C). The surface roughness of the molded product was measured and found to be 50.8 μm. The void content in the tool surface side skin panel was 1.57%.

(Example 3) Using the same resin composition as in Example 1, the same prepreg and sandwich structure were prepared. However, since the basis weight of the resin film was 50 g / m ² , the resin in the prepreg was prepared. The content rate was 34.5%. The viscosity before irradiation was 12 Pa · sec (70 ° C.), while the viscosity after irradiation was 124 Pa · sec (70 ° C.). 1
The viscosity at 00 ° C. was 56 Pa · sec. When the surface roughness of the molded product was measured, it was 26.4 μm, which was inferior to that of Example 1. The void content in the tool-side skin panel was as high as 0.71%.

(Example 4) A carbon fiber woven fabric having a strand tensile strength of 3.53 GPa, a tensile elastic modulus of 230 GPa and a tensile elongation at break of 1.5% was manufactured by Toray Industries, Inc. T30 carbon fiber.
0-3K (3,000 fibers, fineness 1800 denier,
Plain weave carbon fiber fabric with a hook drop value of 95 mm and a surface area ratio of 1.35 by AFM measurement (cover factor 93.6%, basis weight 193 g / m ² , yarn thickness 0.13 m)
m and a yarn width / thread thickness ratio of 12.1) were obtained in the same manner as in Example 1 to obtain a prepreg and a sandwich structure.
The viscosity of the resin film before irradiation was 12 Pa · sec (70 ° C), while the viscosity after irradiation was 113 Pa · sec (70 ° C). The viscosity at 100 ° C. was 47 Pa · sec.

The surface roughness on the tool surface side of the sandwich structure was measured and found to be 20.6 μm. The void content in the tool side skin panel was 0.25%.

[0120]

According to the present invention, it is possible to provide a fiber-reinforced composite material molded article having good surface smoothness and having few internal defects, which is useful as a structural material, an interior material, or an exterior material.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B29K 105: 08 B29K 105: 08 B29L 7:00 B29L 7:00 31:60 31:60 C08L 63:00 C08L 63:00 ZF term (reference) 4F072 AA02 AA04 AA08 AB06 AB08 AB09 AB10 AB28 AB29 AB30 AD03 AD24 AG03 AG06 AG17 AH02 AH22 AJ04 AJ11 AJ16 AK05 AK14 AL04 AL09 AL12 AL16 AL17 A17 A31 A01 AH17AH17A17 AH17A04 AH21A16 AH16A17 AH16A17 AH16A17 AH20 FA06 FB02 FB11 FN11 FN15 FN30 FW43

Claims (16)

[Claims] 1. A method for producing a molded article, which comprises using at least the following constituent elements [A] and [B] and irradiating at least the constituent element [B] with ultraviolet rays, followed by pressure molding. [A] Reinforcing fiber [B] Illuminance at wavelength 365 nm of 4.0 mW / cm ² ,
Thermosetting resin whose viscosity at 70 ° C increases by a factor of 5 or more by UV irradiation with an exposure time of 300 seconds 2. A surface material comprising at least constituent elements [A] and [B] is made into a sandwich structure constituted by sandwiching the constituent element [C], and then the surface material is irradiated with ultraviolet rays. The method for manufacturing the molded article according to claim 1. [C] Core material 3. The method for producing a molded article according to claim 1, wherein the constituent [A] contains at least carbon fibers and / or graphite fibers. 4. The method for producing a molded article according to claim 1, wherein the number of filaments of the multifilament yarn as the constituent [A] is 2500 to 25000. 5. The method for producing a molded article according to claim 1, wherein the constituent element [A] is a woven structure. 6. The method for producing a molded article according to claim 5, wherein the woven structure has a structure selected from plain weave, twill weave, entangled weave, and satin weave. 7. The woven structure comprises a carbon fiber multifilament yarn as a woven yarn and has a fiber basis weight of 100 to 320 g / m ^2.
The method for producing a molded article according to claim 5, wherein 8. The cover factor of the woven structure is 95.
% Or more, The method for producing a molded product according to any one of claims 5 to 7. 9. The molded product according to claim 1, which contains at least an epoxy resin and a resin component having a radical-polymerizable unsaturated bond as the constituent [B]. Production method. 10. The method for producing a molded product according to claim 1, wherein the constituent element [B] contains a component that generates a radical by ultraviolet rays. 11. The component [B] increases its viscosity at 70 ° C. by a factor of 5 or more by irradiating with ultraviolet rays having an illuminance of 4.0 mW / cm ^{2 at} a wavelength of 365 nm and an exposure time of 300 seconds, and increases the viscosity at 100 ° C. to 100 times or more. A thermosetting resin having a viscosity at 1000 Pa · sec or less.
A method for producing a molded article according to any one of 1. 12. The content of the resin having a radical-polymerizable unsaturated bond is in the range of 2 to 30% by weight of the constituent element [B], according to any one of claims 9 to 11. The method for producing a molded article according to 1. 13. The composition according to claim 1, wherein the content of the constituent [B] is in the range of 20 to 50% by weight based on the total weight of the constituent [A] + [B]. A method for producing a molded body according to claim 1. 14. A foam core or a honeycomb core is used as the constituent element [C].
The manufacturing method of the molded object in any one of -13. 15. A sheet material in which the constituent element [B] is impregnated in the gap of the constituent element [A] is prepared, and the sheet material is laminated and then irradiated with ultraviolet rays to be pressure-molded. Item 15. A method for producing a molded article according to any one of Items 1 to 14. 16. The method for producing a molded article according to claim 1, wherein the pressure applied during the molding is 300 MPa or less.