JPH0852815A - Improving method for secondary gluing properties of fiber reinforced plastic molded product - Google Patents

Abstract

PURPOSE:To obtain an improving method for secondary gluing properies of an FRP molded product using thermosetting resin capable of being cured by radical polymerization as a matrix. CONSTITUTION:After molding a fiber-reinforced plastic made product using the thermosetting resin capable of being cured by radical polymerization method as a matrix, a position requiring secondary gluing is preliminarily positioned on a surface of a mold. At the positioned place, a sealing material is applied or attached to an end part of, at least, one side face of a sheetlike molded product (A) having a thickness within a range of 0.5mm-1.5mm cured under a state wherein the thermosetting resin capable of being cured by radical polymerization is taken as a matrix, fiber is taken as a reinforcing material, and both faces are brought in contact with air or oxygen. Then the sealing material is laid so as to come in contact with the mold. Then, the thermosetting resin and reinforcing fiber are laminated on the surface of the mold or the sheet like molded product (A) to improve secondary gluing properties of the fiber reinforced plastic molded product to be molded thereby.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber-reinforced plastics (hereinafter collectively referred to as FRP) molded article having a base material of a thermosetting resin which can be cured by a radical polymerization method, and a surface in contact with the mold. For more details on the secondary adhesion improving method of F, such as septic tanks, bathtubs, boats and ships, pipes, etc.
The present invention relates to a method for improving the adhesive force when the thermosetting resin and reinforcing fibers are laminated and adhered (hereinafter referred to as secondary adhesion) to attach a component or the like to the surface of the RP molded product that is in contact with the mold.

[0002]

2. Description of the Related Art A surface of a FRP molded product having a thermosetting resin that can be cured by a radical polymerization method as a base material, which is in contact with a mold, is a smooth surface and an anchor effect cannot be expected.
During molding, it is not in contact with air, so curing is likely to proceed and it is difficult to expect chemical bonding, and because a mold release agent is applied to the mold, it also adheres to the molded product. At present, the adhesiveness is extremely poor, and sufficient secondary adhesive strength cannot be obtained even if an adhesive is applied to the adhered portion.

Conventionally, in order to improve this secondary adhesion,
A method is generally adopted in which the smooth surface is roughened in advance by a mechanical method such as polishing the surface of the FRP molded product where secondary bonding is to be performed with a rotary file to exert the anchor effect, and at the same time the release agent that has adhered is removed. ing.

[0004]

However, this method has a very serious problem in terms of work environment hygiene because a large amount of dust is generated, and in addition, it requires a considerable amount of time and labor for the treatment, resulting in a high productivity. It has the drawbacks that it does not rise and that the polishing tends to vary, resulting in variation in the secondary adhesive force and difficulty in process control.

Therefore, an object of the present invention is to use an FR containing a thermosetting resin which can be cured by a radical polymerization method as a base material.
It is to improve the secondary adhesion of P molded products.

[0006]

[Means for Solving the Problems]
The P-molded product does not require any post-treatment process such as polishing with a rotary file on the surface of the part where the secondary bonding is to be performed, and the secondary bonding force is more stable than when the bonding surface is polished. As a result of earnestly studying the problems, the present invention has been completed.

That is, according to the present invention, 1) in advance, after molding a product made of fiber reinforced plastics having a thermosetting resin which can be cured by a radical polymerization method as a base material, a secondary adhesion is required The thermosetting resin that can be cured by the radical polymerization method was used as the base material, and the fiber was used as the reinforcing material at the position where it was cured by contacting it with air or oxygen. Sheet-like molding (A) having a thickness in the range of 0.5 mm to 1.5 mm
Of at least one end of the seal material is applied or adhered, laid so that the seal material contacts the mold, then,
The present invention relates to a method for improving secondary adhesiveness of a fiber-reinforced plastic molded article, which comprises laminating and molding the thermosetting resin and a reinforcing fiber on a mold surface and a sheet-shaped molded article (A). Or, 2) pre-positioning on the surface of the mold a position where secondary adhesion is required after molding a product made of fiber reinforced plastics having a thermosetting resin that can be cured by a radical polymerization method as a base material, A thermosetting resin that can be cured by a radical polymerization method is used as a base material at the positioning position, and fibers are used as a reinforcing material and cured on both sides in contact with air or oxygen. Laying so that the roving-like fiber surface at the end of the sheet-like molded article (B) having a thickness in the range of at least one end of which the roving-like fiber is integrated is in contact with the mold. Then, the present invention relates to a method for improving secondary adhesion of a fiber-reinforced plastic molded article, characterized by laminating and molding the thermosetting resin and reinforcing fibers on a mold surface and a sheet-shaped molded article (B). Is.

The thermosetting resin used in the present invention is a resin which can be cured by a radical polymerization method,
Specifically, the resin refers to an unsaturated polyester resin, an epoxy acrylate resin, and a urethane acrylate resin, and each contains a polymerizable monomer as a crosslinking agent. Each of these resins uses a peroxide as a catalyst (also referred to as a curing agent) and is used after being cured (radical copolymerization reaction) at room temperature or in the middle or high temperature. However, in the course of curing, the surface layer of the resin that comes into contact with air or oxygen has a function of inhibiting the polymerization of oxygen, and the concentration of the polymerizable monomer in the layer is high because the polymerizable monomer easily volatilizes from the surface layer. Dilute,
The radical copolymerization reaction is hindered to form an uncured state. Generally, when making a thick FRP molded product, this phenomenon is used for molding. For example, 10 mm thick FRP
When forming a molded product, if a thickness of 10 mm is laminated at one time, the exothermic phenomenon of the thermosetting resin (polymerization heat) and the accompanying shrinkage of the curing may cause a phenomenon of peeling between the resin and the glass fiber as a reinforcing material, or a mold. A good molded product cannot be obtained due to partial peeling of the molded product from. As a solution, first, a layer having a thickness of 5 mm is laminated on the surface of the mold (referred to as primary lamination, the surface opposite to the surface of the mold is in contact with air), and after curing, an additional 5 mm is placed on the air contact surface. A method of stacking thicknesses (called secondary stacking), that is, molding in two steps is common.
In this case, the air contact surface of the primary laminate is in an uncured state, but the contact with the air (or oxygen) is blocked by the secondary laminate, and the polymerizable monomer is newly supplied,
Curing of the interface progresses and good adhesion is exhibited. On the contrary, when it is desired to sufficiently cure the air contact surface of the primary laminate, that is, when the secondary adhesion is not required, wax is added to the thermosetting resin to float on the surface to form a film, or a suitable film is formed. The object is achieved by covering the surface with a film to block air and also to prevent volatilization of the polymerizable monomer. All of these are publicly known techniques.

The present invention has been completed as a result of extensive studies as to whether or not the known technique can be applied to the improvement of the secondary adhesion by the secondary lamination of the mold surface of the FRP molded product, that is, the surface not in contact with air. It is a thing. That is, the present invention uses a thermosetting resin that can be cured by a radical polymerization method as a base material, and uses fibers as a reinforcing material to cure both surfaces in contact with air or oxygen, that is, both surfaces are uncured. First, a thin FRP sheet-like molded product having a thickness in the range of 0.5 mm to 1.5 mm is prepared and prepared. Next, after the molding of the FRP product, the part requiring the secondary bonding is pre-positioned on the surface of the mold. With the sheet-shaped molded product still placed on the positioned mold, FRP
When the above-mentioned lamination is carried out, the thermosetting resin enters the gap between the mold and the sheet-shaped molded product, and the improvement of the secondary adhesiveness, which is the object of the present invention, cannot be achieved. Therefore, in the first method of the present invention, in order to prevent the thermosetting resin from entering, a sealing material is applied or attached to one end of the sheet-shaped molding, and the sealing material is sufficiently applied to the mold. After laying in contact with each other, FRP is laminated on the mold and the sheet-shaped molded product. In general, a mold is often coated with a release agent in advance, so that in order to prevent the surface of the sheet-shaped molded product from coming into direct contact with the mold, not only the end portion of the sheet but also a suitable one as necessary. It is desirable to apply or attach a sealing material in addition to the position. FRP created by this method
Since the uncured state is formed in the part of the mold surface of the molded product where the secondary bonding is performed, the secondary bonding property is excellent.

Next, in the second method of the present invention, as the FRP sheet-shaped molded product, a sheet-shaped molded product in which roving fibers are integrated at least at one end is used.
The purpose of integrating the roving-like fibers on at least one end is to simplify the step of applying or attaching the sealing material. The sheet-shaped molded product in which the roving-shaped fibers are integrated is effective for a cylindrical FRP molded product. For example, the combined treatment septic tank is often a cylindrical molded product, and has many secondary adhesive portions in the circumferential direction of the mold surface. In this case, the sheet-shaped molded product having a predetermined width is wound in the circumferential direction of the cylindrical mold so that the roving-shaped fibers are sufficiently in contact with each other, and the both ends are aligned and fixed with a double-sided tape from the mold side. It is possible to prevent the thermosetting resin from penetrating into the gap between the mold and the sheet-shaped molded product at that time. In this case as well, in order to prevent the surface of the sheet-shaped molded product from directly contacting the mold, not only the end portion of the sheet, but also the roving-shaped fibers are integrated at appropriate positions as necessary, or Alternatively, it is desirable to apply or attach a sealing material. FR created by this method
Since the uncured state is formed in the portion of the mold surface of the P-molded product where the secondary bonding is performed, similarly good secondary bonding is exhibited.

[0011]

In the present invention, the thermosetting resin which can be cured by the radical polymerization method means, as mentioned above, unsaturated polyester resin, epoxy acrylate resin and urethane acrylate resin. The unsaturated polyester resin means an α, β-unsaturated dibasic acid such as maleic acid or fumaric acid or an anhydride thereof and orthophthalic acid, isophthalic acid,
Saturated dibasic acids or their anhydrides such as terephthalic acid, adipic acid, sebacic acid, tetrahydrophthalic acid, endomethylenetetrahydrophthalic acid, tetrabromophthalic acid, dibromotetrahydrophthalic acid, and ethylene glycol, propylene glycol, diethylene glycol, dipropylene Glycol, 1,3-butanediol, 1,
6-hexanediol, neopentyl glycol, hydrogenated bisphenol A, propylene oxide adduct of bisphenol A, ethylene oxide adduct of bisphenol A, dibromoneopentyl glycol, 1,4-
Polymerization using unsaturated polyester obtained by esterification reaction with polyhydric alcohols such as cyclohexanedimethanol, 1,4-butanediol, glycerin, trimethylolpropane, trimethylolethane, ethylene oxide and propylene oxide as a crosslinking agent It is a liquid resin dissolved in a polar monomer. Further, a dicyclopentadiene, a cyclopentadiene-maleic acid adduct or a bromine adduct thereof can be used as a substitute for the unsaturated polyester raw material.

The epoxy acrylate resin is a cross-linking agent of an epoxy acrylate obtained by esterifying an unsaturated monobasic acid such as acrylic acid or methacrylic acid with an epoxy compound having at least one epoxy group in the molecule. It is a liquid resin dissolved in a polymerizable monomer used as.

The urethane acrylate resin is an esterification reaction of the polyhydric alcohol used in the production of unsaturated polyester or the saturated dibasic acid or its anhydride used in the production of unsaturated polyester. Saturated polyester polyol and tolylene diisocyanate (commonly referred to as TDI) obtained in
4,4-diphenylmethane diisocyanate (generally M
Urethane referred to as DI) or 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl-isocyanate (generally referred to as IPDI) to have an isocyanate group at the end of the molecule. The compound is synthesized and then 2-hydroxyethyl methacrylate or 2-hydroxyethyl acrylate is subjected to addition reaction, or first, 2-hydroxyethyl methacrylate or 2-hydroxyethyl acrylate and TD are used.
Urethane obtained by subjecting I, MDI or IPDI to an addition reaction to synthesize a compound having an isocyanate group at one end of the molecule, and then subjecting this to the polyhydric alcohol or the saturated polyester polyol It is a liquid resin in which an acrylate is dissolved in a polymerizable monomer used as a crosslinking agent.

The polymerizable monomer used as the crosslinking agent of the present invention is not particularly limited as long as it is radically copolymerized with unsaturated polyester, epoxy acrylate or urethane acrylate, and specifically, styrene, α -Methylstyrene, chlorostyrene, vinyltoluene, divinylbenzene and the like, a part of which may be substituted with diallyl phthalate, diallyl isophthalate, lower esters of acrylic acid or methacrylic acid, triallyl cyanurate and the like. The proportion of the polymerizable monomer in the thermosetting resin is generally 30 to 50% by weight. If the proportion of the polymerizable monomer in the thermosetting resin is less than 30% by weight, the viscosity of the resin becomes too high, and it becomes difficult to impregnate the reinforcing fiber with the resin. On the contrary, the viscosity of the resin becomes too low and the resin is liable to sag, and the curing shrinkage of the resin is increased, and as a result, the molded product is apt to be distorted, which causes deterioration of mechanical properties.

All of the liquid thermosetting resins of the present invention use peroxide as a catalyst at room temperature (about 0 to 50 ° C.) and medium temperature (5).
It can be cured under high temperature (about 100 to 160 ° C).

The peroxide can be cured at room temperature, that is, it can generate radicals by utilizing redox system or thermal decomposition. As the redox system, a combination of methyl ethyl ketone peroxide, cyclohexanone peroxide or acetylacetone peroxide and an organic acid salt of cobalt, or a combination of benzoyl peroxide and an aromatic tertiary amine is generally used. Cobalt naphthenate or cobalt octenoate is generally used as the organic acid salt of cobalt, and dimethylaniline, diethylaniline, and dimethylparatoluidine are generally used as the aromatic tertiary amine.

For medium temperature curing, t-butylperoxy-2-
Ethyl hexanoate, bis (4-t-butylcyclohexyl) -peroxydicarbonate, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane are commonly used as catalysts. In high temperature curing, t-butyl peroxybenzoate and dicumyl peroxide are generally used as catalysts.

The fibers used as the reinforcing material in the present invention include organic fibers such as glass fibers, carbon fibers and vinylon fibers, but glass fibers are the most inexpensive and are generally used. The shape of the fiber is cloth,
There are roving cloths and chopped strand mats, both of which are used, but it is preferable to use chopped strand mats for the surface layer for secondary bonding. The reason is that when a cloth or roving cloth is used for the surface layer for secondary bonding, the fiber content becomes high, that is, the ratio of the thermosetting resin involved in the bonding decreases and the secondary bonding is adversely affected. Is. Therefore, a chopped strand mat is desirable as the fiber reinforcing material for the sheet-shaped molded article in the present invention. When a glass fiber chopped strand mat is used, its content in the FRP molded product is generally 25 to 35% by weight.

When the proportion of the chopped strand mat of glass fiber is less than 25% by weight, the proportion of the resin becomes high, and the obtained sheet-like molded article is partially formed with a layer containing only the resin. This is not preferable because it becomes easy and the mechanical strength of that portion is reduced. On the other hand, if it is more than 35% by weight, the proportion of the resin becomes small, impregnation into the chopped strand mat becomes difficult, and unimpregnated portion of the resin is easily formed in the obtained sheet-shaped molded product, which is not preferable.

The reason for limiting the thickness of the sheet-shaped molded product used in the present invention to the range of 0.5 mm to 1.5 mm is that it is difficult to manufacture a sheet-shaped molded product thinner than 0.5 mm. Even if it can be manufactured, pinholes are likely to occur, and the resin laminated on it will exude to the mold surface, causing a decrease in secondary adhesion.
This is because if the thickness is thicker, the rigidity becomes higher and it becomes difficult to fit the mold having a curvature. The sheet-shaped molded product can be easily produced by impregnating a chopped strand mat of a predetermined size with the liquid thermosetting resin to which a catalyst has been added in advance and curing at room temperature, medium temperature, high temperature and in air. Can be done.

[0021]

EXAMPLES The present invention will be described in more detail with reference to Examples, Comparative Examples, Reference Examples and Comparative Reference Examples, but the present invention is not limited to these Examples. In addition,
All "parts" shown in the examples are "parts by weight" unless otherwise specified.
Means

Reference Example 1 Chopped Strand Mat CM-300 (300 g /
m ^2, the width by cutting the glass fiber mat) manufactured by Asahi Fiber Glass Co. 0.4 m, were prepared mat length 2.5 m. Next, a general-purpose unsaturated polyester resin for hand lay-up and spray-up molding "Yupika 4183PT" (wax not included) manufactured by Nippon Yupica Co., Ltd.
00 g was prepared, and 7 g of commercially available methyl ethyl ketone peroxide was added thereto and mixed well, and then the mat prepared in advance was impregnated with the resin. This mat is hung in a drying oven at 50 ° C. for 1 hour to cure, and a sheet-shaped molded product (a) is obtained.
I got The glass content of the sheet-shaped molded product (a) was 33.
In weight%, the average thickness was 0.63 mm.

Reference Example 2 Chopped Strand Mat CM-380 (380 g /
m ^2, the width by cutting the glass fiber mat) manufactured by Asahi Fiber Glass Co. 0.4 m, were prepared mat length 2.5 m. Next, 1000 g of an unsaturated polyester resin “Iupica 5524P” (wax is not included) manufactured by Nippon Yupica Co., Ltd. for laminating isophthalic acid was prepared, and 10 g of commercially available methyl ethyl ketone peroxide was added thereto and mixed well, A mat prepared in advance was impregnated with the resin. This mat was hung in a drying oven at 50 ° C. for 1 hour to be cured to obtain a sheet-shaped molded product (b). The glass content of the sheet-shaped molded product (b) was 30% by weight, and the average thickness was 0.87 mm.

Reference Example 3 A resin solution was prepared by mixing 100 parts of epoxy acrylate resin "Neopol 8250H" manufactured by Nippon Yupica Co., Ltd. with 2 parts of commercially available benzoyl peroxide having a concentration of 50% by weight. Next, a chopped strand mat CM-450 with a width of 0.4 m and a length of 2.5 m prepared in advance.
(450 g / m ² , Asahi Fiber Glass Co., Ltd. glass fiber mat) and 2.5 m long roving ER
2310F-183 (Glass roving manufactured by Unitika Yum Glass Co., Ltd.) was dipped and impregnated in the resin liquid.
The two rovings were mounted lengthwise 0.5 cm inward from the edge of the mat. The mat was hung in a drying oven at 100 ° C. for 1 hour to cure, and a sheet-shaped molded product (c) in which rovings were integrated was obtained. The sheet-shaped molded product (c)
The glass portion had a glass content of 28% by weight and an average thickness of 1.12 mm.

Reference Example 4 A resin solution was prepared by mixing 100 parts of a urethane acrylate resin “Yupica 8921” manufactured by Japan Yupica Co., Ltd. with 2 parts of a commercially available benzoyl peroxide having a concentration of 50% by weight. Next, 0.4m wide and 2.5m long prepared in advance
Chopped Strand Mat CM-600 (600g
Two roving ER2310F the / m ^2, Asahi Fiber Glass fiberglass mat, Ltd.) and a length 2.5m
-183 was immersed in the resin solution to impregnate it. The two rovings were mounted lengthwise 0.5 cm inward from the edge of the mat. This mat was hung in a drying oven at 100 ° C. for 1 hour to cure, and a sheet-shaped molded product (d) in which rovings were integrated was obtained. The glass content of the mat portion of the sheet-shaped molded product (d) was 28% by weight, and the average thickness was 1.49 m.
It was m.

The sheet-shaped molded products shown in Reference Examples 1 to 4 were all manually produced, but they can also be continuously produced endlessly. This method includes a method of manufacturing a prepreg in advance when manufacturing an epoxy resin laminated plate industrially (dry laminating method), but it can be manufactured using this prepreg manufacturing facility. An example of this manufacturing equipment is written by Soichi Muroi and Shuichi Ishimura, "Introduction Epoxy Resin" (New Polymer Bunko 25) (Polymer Publishing Co., Ltd., June 2, 1988).
Issued 0th day), page 240, Fig. 8.11.

Comparative Reference Example 1 A polyester film is laid on a flat table and has a width of 0.4.
A chopped strand mat CM-380 (380 g / m ² , glass fiber mat manufactured by Asahi Fiber Glass Co., Ltd.) cut into m and 2.5 m in length was placed. Next, 1000 g of an unsaturated polyester resin “Iupica 5524P” (wax is not included) manufactured by Nippon Yupica Co., Ltd. for laminating isophthalic acid was prepared, and 10 g of commercially available methyl ethyl ketone peroxide was added thereto and mixed well, A mat prepared in advance was impregnated with the resin. This mat with the polyester film attached is put in a drying oven at 50 ° C for 1 hour to cure, and after removing from the drying oven, the polyester film is peeled off. One side is the air contact surface, the other side is the air contact surface. A sheet-shaped molded product (e) was obtained which was cured without being brought into contact with. The glass content of the sheet-shaped molded product (e) was 30% by weight, and the average thickness was 0.87 mm.
Met.

Using the sheet-shaped moldings produced in Reference Examples 1 to 4 and Comparative Reference Example 1, a portion corresponding to the secondary adhesive portion of the fiber-reinforced plastic molded article was prepared. Since each sheet-shaped molded product has a large adhesive area and is inconvenient for the measurement of the secondary adhesive force, the sheet-shaped molded product is cut into a predetermined size shown in FIG. The next adhesive strength test was performed.

(1) The sheet-like moldings produced in Reference Examples 1 to 4 and Comparative Reference Example 1 were cut out, and as shown in FIG. 1, the width (W ₁ ) was 200 mm and the length (L ₁ ) was 65 mm. A size plate was prepared.

(2) W ₁ = 200 mm, L ₂ = 105 m
m-sized chopped strand mat CM-450
(450 g / m ² , Asahi Fiber Glass Co., Ltd. glass fiber mat) with 5 plies (layer) and general-purpose unsaturated polyester resin “Yupica 4183APT” for hand lay-up / spray-up molding manufactured by Japan Yupica Co., Ltd. ) To 150 g, 1.5 g of commercially available methyl ethyl ketone peroxide was added and well mixed to prepare a resin.

(3) CM-45 on the cutout plate of FIG. 1 at the position (L ₂ = 105 mm, W ₁ = 200 mm) shown in FIG.
0 is placed in 2 plies and the resin prepared in advance is laminated so that the glass fiber content is about 30% by weight, and CM-
450 sheet layers 2-1 were obtained. After the lamination was completed, a Teflon tube (outer diameter 2 mm) 3 was set at the position shown in FIG. However, the cutout plate of the sheet-shaped molded product (e) produced in Comparative Reference Example 1 was laminated on the air contact surface.

(4) The remaining CM-450 mat 3 plies were laminated at the position shown in FIG. 3 so that the glass fiber content was about 30% by weight, and allowed to stand at room temperature for 1 day to cure the sheet layer 2.
-2 was obtained. The obtained sheet layers 2-1 and 2-2 correspond to a part of the main body of the fiber-reinforced plastic molded product. A cross-sectional view of the main cured product is as shown in FIG.

(5) The cured product of FIG. 3 was inverted and the polyester film 4 was set at the position shown in FIG. Next, the operation of (3) was repeated. However, in the case of the cut-out plate of the sheet-shaped molded product (e) produced in Comparative Reference Example 1, since it has a non-air contact surface and a smooth surface, it is ground with sandpaper No. 80 and powdered with acetone. After wiping off, the operation of (3) was repeated. Repeat the operation of (4) and CM
Three plies of -450 were laminated and left at room temperature for curing.
Post-curing was performed at 40 ° C. for 16 hours in order to sufficiently proceed the curing, and thus a sheet layer 5 was obtained. The upper portion of the sheet-shaped molded product cutting plate of the sheet layer 5 corresponds to the secondary bonding site. The cross section of this molded product is as shown in FIG. 6 (L ₁ = 65 m
m, L ₃ = 40 mm, T ₁ = about 10 mm).

[0034] (6) molding the cutting and dimensions shown in FIG. 7 (W ₂ = 25 mm in Fig. _{6, L 4 = 50mm, L} 3/2
= 20 mm, T = about 10 mm was prepared, a load was applied to the portion of the Teflon tube through the wire 6, and a tensile peeling test was performed to evaluate the secondary adhesive force. Five pieces (n = 5) of test pieces were prepared for each sheet-shaped molded article and subjected to the test.

Table 1 shows the evaluation results of the secondary adhesive strength by the tensile peel test. Test conditions: test piece n = 5, load speed = 1 mm / min, peel strength = maximum load / width of test piece, peel energy = area value of load and displacement

[0036]

[Table 1]

As is clear from the results shown in Table 1, Reference Example 1
The peel strength and peel energy of the test pieces of Examples 1 to 4 obtained by the secondary bonding method using the sheet-shaped molded products produced in Examples 1 to 4 were produced in Comparative Reference Examples. It can be seen that it has a higher value than the test piece of Comparative Example 1 in which the primary laminated plate (primary base material) was sanded and secondarily contacted, and that it has excellent adhesive strength. As for the values of Examples 1 to 4, the peel strength was about 1.5 times and the peel energy was 4.5 to 5.0 times that of Comparative Example 1. In the fractured state of Comparative Example 1, both phenomena of fracture of the laminate (base material) and interfacial peeling of the secondary adhesive portion were observed, whereas the sheet-shaped molded products of Reference Examples 1 to 4 were used. In all of the fracture states, the laminate was destroyed, and no interfacial peeling at the secondary adhesive portion was observed.

[0038]

EFFECT OF THE INVENTION When the sheet-like molded article is used for the secondary lamination of the FRP molded article by the method of the present invention, the smooth surface (non-air contact surface) of the conventional molded article is polished by a rotary file and It became clear that it has a high secondary adhesive force as compared with the method of performing the subsequent lamination. As a result, (1) the work environment is improved because the polishing work can be omitted, (2) the labor of the polishing work can be saved, and (3) the productivity is improved by shortening the work process. (4) By obtaining a high secondary adhesive force, effects such as improvement in quality of FRP molded products can be obtained, and the influence on the FRP industry is extremely large.

[Brief description of drawings]

FIG. 1 is a plan view of a cutout plate of a sheet-shaped molded product.

FIG. 2 is a plan view of a cutout plate of a sheet-shaped molded product in which two plies of CM450 mat are laminated on the upper surface and a Teflon tube is installed.

FIG. 3 is a plan view of a cutout plate of a sheet-shaped molded product in which a CM450 mat of 3 plies is further laminated on the CM450 mat shown in FIG.

4 is a cross-sectional view of the sheet-shaped molded product shown in FIG.

5 is a plan view of the sheet-shaped molded product shown in FIG. 3, showing a state where the sheet-shaped molded product is inverted and a polyester film is placed thereon.

FIG. 6 is a cross-sectional view of a molded product obtained by stacking two plies of CM450 mat on the molded product shown in FIG. 5, placing a Teflon tube at a predetermined position, further stacking three plies of CM450 mat, and curing. .

7 is a perspective view showing a state in which a peeling test is performed on a test piece obtained by cutting the molded product shown in FIG.

[Explanation of symbols]

1 Sheet-shaped molded product cut-out plate 2-1 CM450 mat in which 2 plies are laminated on the cut-out plate 2-2 CM450 mat in which 3 plies are further laminated on 2-ply CM450 on the cut-out plate 3 Teflon tube 4 Polyester film 5 CM450 mat with 5 plies laminated on the opposite side of the cutting plate 6 Wire

Claims (6)

[Claims] 1. A position where secondary adhesion is required after molding a product made of fiber reinforced plastics having a thermosetting resin which can be cured by a radical polymerization method as a base material is previously positioned on the surface of the mold. , The thermosetting resin that can be cured by the radical polymerization method is used as the base material at the positioning position,
A sealing material on at least one end of a sheet-like molded article (A) having a thickness in the range of 0.5 mm to 1.5 mm, which is cured by using fibers as a reinforcing material while contacting both surfaces with air or oxygen. And laying it so that the sealing material contacts the mold, and then laminating and molding the thermosetting resin and the reinforcing fiber on the mold surface and the sheet-shaped molded product (A). A method for improving the secondary adhesion of fiber-reinforced plastics molded products. 2. The fiber-reinforced plastics molded article according to claim 1, wherein the thermosetting resin which can be cured by a radical polymerization method is an unsaturated polyester resin, an epoxy acrylate resin or a urethane acrylate resin. Secondary adhesion improvement method. 3. The method for improving secondary adhesion of a fiber-reinforced plastic molded article according to claim 1, wherein the reinforcing material is a glass fiber cloth, a roving cloth or a chopped strand mat. 4. A position where secondary adhesion is required after the molding of a product made of fiber reinforced plastic having a base material of a thermosetting resin which can be cured by a radical polymerization method is previously positioned on the surface of the mold. , The thermosetting resin that can be cured by the radical polymerization method is used as the base material at the positioning position,
Fibers are used as a reinforcing material and cured on both sides in contact with air or oxygen, and have a thickness in the range of 0.5 mm to 1.5 mm, and at least one end has roving-like fibers integrated. The sheet-like molded product (B) was laid so that the roving-like fiber surface at the end thereof was in contact with the mold, and then the thermosetting resin and the reinforcing fiber were laid on the mold surface and the sheet-shaped molded product (B). A method for improving the secondary adhesiveness of a fiber-reinforced plastic molded product, which comprises laminating and molding. 5. The fiber-reinforced plastics molded article according to claim 4, wherein the thermosetting resin which can be cured by a radical polymerization method is an unsaturated polyester resin, an epoxy acrylate resin or a urethane acrylate resin. Secondary adhesion improvement method. 6. The method for improving secondary adhesion of a fiber-reinforced plastic molded article according to claim 4 or 5, wherein the reinforcing material is a glass cloth, a roving cloth or a chopped strand mat.