JPS6050210B2 - Manufacturing method of glass fiber reinforced resin board - Google Patents

Description

Detailed Description of the Invention The present invention involves impregnating or mixing glass fibers with a polymerizable liquid composition in which a dialkyl peroxydicarbonate as a polymerization initiator is dissolved in a syrup mainly composed of methyl methacrylate and polymerizing and curing the composition. The present invention relates to a method for manufacturing a glass fiber reinforced resin plate.

In recent years, glass fiber-reinforced resin flat plates and corrugated plates containing methyl methacrylate as a main component have become useful as building materials, agricultural lighting boards, and structures such as outdoor cooling towers due to their excellent weather resistance. It is highly valued and widely used.

However, due to its low production efficiency, it has the disadvantage of higher manufacturing costs than commercially available glass fiber reinforced unsaturated polyester resin sheets.Therefore, there is a strong demand for improved productivity, and high production efficiency that polymerizes and cures in a short time is required. Polymerization technology was required. On the other hand, in general, if the polymerization curing time is shortened, disadvantages such as foaming of the glass fiber reinforced resin plate during polymerization and curing, deterioration of crazing resistance, and significant decrease in strength appear. Therefore, for example, the Special Publick Publication No. 47-7637
As is known from Japanese Patent Application Laid-open No. 49-459N, the polymerization curing time could not be reduced to less than 2 to 4 gin. The present invention provides a method for manufacturing a glass fiber reinforced resin board with low manufacturing cost and excellent quality. Glass fibers are impregnated with or mixed with a polymerizable liquid composition prepared by dissolving dialkyl peroxydicarbonate as a polymerization initiator in syrup with a polymerization rate of 15 to 35% by weight containing an unsaturated triad monomer, and then polymerized and cured. The present invention is characterized in that glass fiber-reinforced methacrylic resin plates can be manufactured efficiently. Furthermore, the present invention has discovered a method for producing glass fiber-reinforced methacrylic resin plates of excellent quality while shortening the polymerization and curing time after impregnating or mixing the composition into glass fibers to within 15 J-. be. By the way, in order to make glass fiber-reinforced methacrylic resin boards lower in manufacturing cost than commercially available glass fiber-reinforced unsaturated polyester resin boards and to have excellent marketable quality, the following four conditions must be met. is necessary.

(1) Polymerization and curing time is within 1 gin, preferably within 1 gin.

(2) No bubbles are generated in the resin board during polymerization and curing, that is, no polymerization foaming is present in the manufactured glass fiber reinforced resin board.

(3) The strength of the manufactured resin plate is excellent.

(4) The manufactured resin plate has excellent crazing resistance,
and have excellent weather resistance.

That is, when the polymerizable liquid composition is impregnated or mixed into glass and then polymerized and cured, the polymerization and curing time is 1.
Unless it is less than one particle, preferably less than one particle, the manufacturing cost will not be competitive with glass fiber reinforced unsaturated polyester resin plates, and this shows that improving production efficiency is an essential condition.

Furthermore, if air bubbles are present in the manufactured resin plate, it will impair its commercial value, and since these air bubbles are generated during polymerization and curing, it is especially necessary to appropriately select polymerization conditions.

In addition, since the manufactured resin plates are used as building materials and agricultural structures, they are required to have strength, so it is necessary to not only improve the production efficiency of the resin plates but also to take care not to reduce their strength.

In addition, since the manufactured resin boards are often used outdoors, they have excellent crazing resistance to prevent crazing on the surface of the resin board, and are also resistant to coloring, discoloration, and whitening. It is also necessary to have excellent weather resistance so that it does not deteriorate. 4 mentioned above
These four conditions are essential in order to make the manufacturing cost of glass fiber reinforced methacrylic resin board lower than that of glass fiber reinforced unsaturated polyester resin board, and to make it marketable and of excellent quality. Must be satisfied at the same time.

The present invention provides a method for manufacturing a glass fiber reinforced methacrylic resin plate that satisfies the above four conditions at the same time.

That is, in particular, the present invention uses dialkyl peroxydicarbonate as a polymerization initiator in a specific range of amounts and under conditions of a specific heat curing temperature range. Said 4. We have discovered a method for manufacturing a glass fiber reinforced methacrylic resin plate that satisfies these two conditions at the same time.

The dialkyl peroxydicarbonate which is the polymerization initiator of the present invention is one in which each alkyl group has 3 to 1 carbon atoms, such as diisopropyl peroxydicarbonate, di-n-butyl peroxydicarbonate, di- 1s0-butyl peroxydicarbonate, di-Sec-butyl peroxydicarbonate, dicyclohexyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-ethoxyethyl peroxydicarbonate, di-3-methoxybutyl peroxydicarbonate, One type or a combination of two or more types selected from bis(4-tertiarybutylcyclohexyl) peroxydicarbonate and the like can be used. Furthermore, 1 Cfi is calculated based on the weight of the dialkyl peroxydicarbonate used in the present invention.
If the weight exceeds the amount, plasticizers that do not easily react with dialkyl peroxy dicarbonates such as dibutyl phthalate and dioctyl phthalate, and dialkyl peroxy dicarbonates such as mineral spirits and triethylene are used for handling and work safety purposes. Diluents that are less reactive with dicarbonates can be used with dialkyl peroxydicarbonates. The amount of dialkyl peroxydicarbonate used as a polymerization initiator of the present invention is determined by the relationship between the number of molar parts of dialkyl peroxydicarbonate per 10 parts of the syrup of the present invention and the heat curing temperature (°C) as shown in Figure 1. Points A (5×10-5, 90) and B (1.5X
10-3, 90), C (1.5×10-3, 70), D
(1.7 cut 0-4, 70), E (5 x 10-5, 85)
In order to manufacture a resin plate that satisfies the four conditions mentioned above, it is important to select the heat curing temperature and the amount of dialkyl peroxydicarbonate to be included in the closed region formed by connecting each point with a straight line. It is necessary. Furthermore, the syrup used in the present invention, which is mainly composed of methyl methacrylate and contains a polyfunctional unsaturated monomer having two or more unsaturated groups, has a polymerization rate of 15 to 35% by weight, preferably 20% by weight.
~3% saliva is used, and the viscosity of the syrup is 2.
It is preferable that it is 0.2 poise or less at 5°C.

When the polymerization rate of the syrup is less than 15% by weight, the production efficiency of the resin plate deteriorates. Even if polymerization is carried out under conditions in a closed area, it is difficult to produce a resin plate of excellent quality with a polymerization and curing time of less than 1 gin, and it is even more impossible to reduce the polymerization and curing time to less than 1 gin. . On the other hand, when the polymerization rate of the syrup is more than 35% by weight, the viscosity of the syrup increases, making it difficult to impregnate or mix the polymerizable liquid composition into glass fibers, and making it difficult to remove air bubbles, which is not preferable. It is preferable that the viscosity of the syrup is 0.2 poise or more at 25°C. If it is less than 0.2 poise, foaming will easily occur during polymerization and curing when the polymerization and curing time is shortened, and the quality of the manufactured resin board will be reduced. In particular, strength and crazing resistance tend to decrease. On the other hand, if the syrup viscosity becomes high, it becomes difficult to impregnate or mix the polymerizable liquid composition into glass fibers, and it becomes difficult to remove air bubbles, so the upper limit of the syrup viscosity is usually up to 100 poise. That is, the syrup of the present invention has a polymerization rate of 15 to 35% by weight and a temperature of 25°C.
It is preferable to use one having a viscosity of 0.2 to 100 poise. Furthermore, in the present invention, the number average degree of polymerization of the polymer in the syrup is 500 or more, the weight average degree of polymerization is 2,500 or less, and the polymerization degree is expressed as the ratio of the weight average degree of polymerization to the number average degree of polymerization of the polymer. It is preferable to use a syrup whose polydispersity of distribution is 72.5 or less. Generally, the viscosity of the syrup is determined by the polymerization rate of the syrup and the weight average degree of polymerization of the polymer, and the higher the viscosity of the syrup, the higher the viscosity of the syrup.
It is preferable to lower the average degree of polymerization of the polymer to 0.00 poise or less.

However, when the polymerization rate is 15 to 35% by weight, the viscosity of C is 0.
．． Even if the syrup is 2 to 100 poise, if the number average polymerization degree of the polymer is low, there will be disadvantages such as poor machinability when cutting the manufactured resin board, the strength of the resin board itself, or crazing resistance. The present inventors have found that these defects change rapidly when the number average degree of polymerization of the polymer in the syrup reaches 500. Polymers have a degree of polymerization distribution, and the average degree of polymerization is greater than the number average degree of polymerization, and the degree of polymerization is typically expressed as the polydispersity, which is the ratio of the two, as a measure of the breadth of the degree of polymerization distribution. As mentioned above, the viscosity of the syrup increases as the polymerization rate of the syrup increases and as the average polymerization degree of the polymer increases.
In order to shorten the polymerization and curing time of the polymerizable liquid composition and increase productivity, the polymerization rate of the syrup is increased, and the polymerizable liquid composition is easily impregnated into or mixed with glass fibers, and air bubbles are easily removed. Therefore, it is required to lower the polymerization average degree of polymerization. In the present invention, the viscosity of the syrup is 25°C.
The polymerization rate is 15 to 100 poise in the range of 0.2 to 100 poise.
35% by weight to improve production efficiency, and have no defects in the quality of the resin plate produced, especially in machinability when cutting the resin plate, the strength of the resin plate itself, or crazing resistance, etc. In order to achieve this, the number average degree of polymerization of the polymer in the syrup is 500 or more, and the polymerization average degree is 2500
It is preferable to use a syrup having a polydispersity of 2.5 or less and a polydispersity of the polymerization degree distribution expressed as a ratio between the polymerization average degree of polymerization and the number average degree of polymerization of the polymer.

The syrup used in the present invention is mainly composed of methyl methacrylate and contains a polyfunctional unsaturated monomer having two or more unsaturated groups. The amount of the polyfunctional unsaturated monomer used is in the range of 0.2 to 10% by weight based on the total weight of the syrup. Examples of the polyfunctional unsaturated monomer include ethylene glycol diacrylate, diethylene glycol diacrylate, etc. Acrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, decamethylene glycol diacrylate, trimethylolpropane diacrylate, trimethylolpropane triacrylate, allyl acrylate, diallyl acrylate, crotyl acrylate, mesaryl acrylate, Tetramethylolmethane triacrylate, ethyne glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol methacrylate, decamethylene glycol dimethacrylate, trimethylolpropane dimethacrylate, trimethylolpropane trimethacrylate, allyl methacrylate, diallyl methacrylate, Chlor methacrylate, mesatyl methacrylate, tetramethylolmethane methacrylate,
selected from divinylbenzene, triallyl isocyanurate, diallyl phthalate, diallyl isophthalate, diallyfluterephthalate, diallylbenzene, diethylene glycol bisallyl carbonate, diallyl maleate, diallyl fumarate, diallyl itaconate, divinyl ether, dimesalyl ether At least one polyfunctional unsaturated monomer is used.

The amount of polyfunctional unsaturated monomer is 0 based on the total weight of the syrup.
．． If the amount is less than 1%, the strength of the produced resin plate will be low and the crazing resistance will be low, so it is preferable, while if it is more than 1%, the polymerizable liquid composition will be mixed with glass fibers. When the resin is impregnated or mixed with the resin and then polymerized and cured, the surface of the resin plate partially becomes depressed, which is undesirable because the appearance is impaired.

In the present invention, dialkyl peroxydicarbonate is added as a polymerization initiator to a syrup with a polymerization rate of 15 to 35% by weight, which is mainly composed of methyl methacrylate and contains a polyfunctional unsaturated monomer having two or more unsaturated groups. After impregnating or mixing glass fiber with the dissolved polymerizable liquid composition, the relationship between the heating curing temperature (°C) at which the composition polymerizes and the amount of dialkyl peroxydicarbonate used falls within the closed region shown in Figure 1. By polymerizing and curing the composition under the following conditions, it is possible to easily produce a glass fiber-reinforced methacrylic resin board that simultaneously satisfies the above four conditions.

The amount of dialkyl peroxydicarbonate in FIG. 1 of the present invention is expressed on a logarithmic scale. In addition to dialkyl peroxydicarbonate, which is the polymerization initiator of the present invention, other polymerization initiators may be used in combination as necessary, as long as the amount is within a range that does not cause polymerization and foaming in the resin plate manufactured by the present invention. For example, lauroyl peroxide or tertiary butyl peroxypivalate may be used.

In addition, in the present invention, the syrup may contain heat stabilizers, ultraviolet absorbers, colorants, various fillers, etc., as necessary, as long as the amounts are within the range that achieves the purpose of the present invention. .

In addition, the syrup of the present invention may contain an unsaturated monomer copolymerizable with methyl methacrylate, for example, for the purpose of improving the adhesion between the glass fibers and methacrylic resin of a glass fiber reinforced methacrylic resin board. In addition, other unsaturated monomers copolymerizable with methyl methacrylate may be included in the syrup as necessary, such as carboxyl groups such as acrylic acid and methacrylic acid, 2-hydroxyethyl acrylate, and 2-hydroxyethyl acrylate. Hydroxyl groups such as methacrylate, glycidyl acrylate,
An unsaturated monomer having an epoxy group such as glycidyl methacrylate, acrylic acid, alkyl ester, etc. may also be used.

In order to prepare a syrup with a polymerization rate of 15 to 35% by weight that contains methyl methacrylate as a main component and contains a polyfunctional unsaturated monomer having two or more unsaturated groups, methyl methacrylate is partially polymerized to form a syrup, and then the polyfunctional unsaturated monomer is added to this syrup to achieve a predetermined polymerization rate and composition. Either by partially polymerizing methyl methacrylate to achieve a predetermined polymerization rate and composition, or by dissolving the polymer obtained by polymerizing methyl methacrylate in a mixture of methyl methacrylate and the polyfunctional unsaturated monomer to achieve a predetermined polymerization. There are ways to adjust the ratio and composition.

At any stage of these preparation methods, the additives, fillers, and unsaturated monomers copolymerizable with methyl methacrylate may be added and mixed. The manufacturing equipment to which the present invention is applied is not particularly limited as long as it is an equipment that manufactures glass fiber reinforced resin plates generally known as flat plates or corrugated plates, and can manufacture glass fiber reinforced unsaturated polyester resin plates. It goes without saying that the present invention can be applied to devices.

When implementing the manufacturing method of the present invention, glass, cellophane, film,
Polyester film, PVA film, PE film, PP film, aluminum, iron, stainless steel, etc. can be molded into any shape, such as a flat plate, a corrugated plate, etc. within a mold, or between continuously moving belts of stainless steel, etc., or between the above-mentioned films. It is also possible to post-process it by thermoforming or the like.

The glass fibers used in the present invention are conventionally known, and the shapes are roping, surfing mat,
Chopped strands, chopped strands,
It is suitable for use in any shape such as satin weave, lattice weave, plain weave, open plain weave, twill weave, or net, and can be of any type such as E glass fiber or C glass fiber. There is no change in the usage rate from before,
The amount is preferably 10 to 4% by weight based on the weight of the resin plate normally produced.

In the present invention, glass fibers are impregnated or mixed with the polymerizable liquid composition and then polymerized and strengthened to obtain a resin plate. However, the heating curing temperature may be kept constant throughout, or may be changed stepwise or continuously. Further, heat treatment may be performed subsequent to heat curing for the purpose of reducing residual monomer in the resin plate to be produced.

Generally, the heat treatment temperature is preferably 110 to 150°C. The glass fiber-reinforced methacrylic resin plate obtained by the present invention is inexpensive to manufacture and has excellent quality, and is widely used as a building material or a structure for agricultural use.

EXAMPLES Next, the present invention will be specifically explained with reference to Examples, but the present invention is not limited thereto.

The percentages in the examples are percentages by weight. In addition, polymerization foaming in the examples was determined by visually observing the obtained resin A plate to determine the presence or absence of bubbles, and craze resistance was determined by immersing the obtained resin plate in ethyl acetate for 1 minute to determine whether or not craze occurred. The strength was determined by measuring the bending strength according to ASTM D-790, and the weather resistance was determined by visually examining the external appearance by conducting a gate accelerated exposure test according to ASTM D-1499.

Example 1 Methyl methacrylate monomer containing 0.09% azobisdimethylvaleronitrile was preheated to 80°C using a jacketed single-tube in a stirred tank reactor equipped with a ribbon-shaped stirring blade to carry out a tank reaction. It was fed continuously so that the average residence time in the vessel was 3.6 minutes.

Stirring was carried out at a speed of 800 revolutions/minute, and the temperature of the reactor was kept at 1
The temperature was maintained at 40°C and the pressure was 3 atmospheres gauge. The syrup exiting the reactor is rapidly cooled and the polymerization rate of the syrup is 30%, 25
A syrup with a viscosity of 22 poise at °C was obtained. The number average degree of polymerization of the polymer in the syrup was 600, and the average polymerization degree was 1,224. Therefore, the polydispersity of the polymerization degree distribution expressed as the ratio of the polymerization average degree of polymerization to the number average degree of polymerization is 2.
．． It was 04. An appropriate amount of bis(4-tertiarybutylcyclohexyl) peroxydicarbonate as a polymerization initiator and an appropriate amount of ethylene glycol dimethacrylate as a polyfunctional unsaturated monomer were mixed and dissolved in this syrup and degassed under reduced pressure. The polymerizable liquid composition is mixed with glass fiber (
CR-213 (A-7S) manufactured by Nippon Glass Fiber Co., Ltd. was injected into a flat plate polymer mold uniformly filled so that the final resin plate contained 25% to impregnate the glass fibers, and then this polymer mold was It was immersed in a heating bath to polymerize and harden. During this time, the temperature rise due to polymerization heat generation was measured, and the time until the maximum temperature was reached is shown as the polymerization curing time in Table 1. After reaching the maximum temperature, the temperature was cooled to room temperature and the thickness was about 1 cm from the inside of the polymerization mold.
A glass fiber reinforced methacrylic resin plate of 7T0TL was taken out. As shown in Table 1, the resulting resin plates showed no polymerization foaming despite the extremely short polymerization time, and also had good crazing resistance.

Furthermore, no change in appearance was observed in the accelerated exposure test of 10001 Terama. Example 2 Methyl methacrylate monomer containing 0.055% diisopropyl peroxydicarbonate was placed in a stirred tank type reactor equipped with the ribbon-shaped stirring blade used in Example 1 using a jacketed single tube.
Preheated to 60°C, the average residence time in the tank reactor was 4.
．． It was continuously fed for 6 minutes.

Stirring was carried out at a speed of 800 rpm and the temperature of the reactor was 13
The pressure was maintained at 0° C. and 2.5 atmospheres gauge. The syrup exiting the reactor is rapidly cooled, and the polymerization rate of the syrup is 25%.
A syrup having a viscosity of 9.7 poise at 25°C was obtained.
The number average degree of polymerization of the polymer in the syrup is 700, the weight average degree of polymerization is 1435, and the polydispersity of the polymerization degree distribution is therefore 2.05. An appropriate amount of bis-1 (4-tert-butylcyclohexyl) peroxydicarbonate as a polymerization initiator and an appropriate amount of tetraethylene glycol dimethacrylate as a polyfunctional unsaturated monomer were mixed and dissolved in this syrup and degassed under reduced pressure. The resulting polymerizable liquid composition was injected into a flat plate polymerization mold in the same manner as in Example 1, impregnated into glass fibers, and polymerized and cured to obtain the results shown in Table 2.

In all of the obtained resin plates having a thickness of about 1 TIOn, no polymerization foaming was observed despite the extremely short polymerization time, and the crazing resistance was also good.

Furthermore, no change in appearance was observed even in an accelerated exposure test between 1000111V. Example 3 When 20% of methacrylic resin (trade name: Sumipetsu BMHL, manufactured by Sumitomo Chemical Industries, Ltd.) was dissolved in methyl methacrylate, the viscosity at 25°C was 1 poise.

The number average degree of polymerization of the polymer in the syrup is 680, the weight average degree of polymerization is 1428, and the polydispersity of the polymerization degree distribution is therefore 2.1. This syrup was added with 0.3% bis(4-tertiarybutylcyclohexyl)peroxydicarbonate (0.75 parts by mole per 100 parts by weight of the syrup) and a polyfunctional unsaturated monomer. Trimethylolpropane triacrylate 2 as a polymer
．． A polymerizable liquid composition prepared by mixing and dissolving 5% and degassing under reduced pressure,
In the same manner as in Example 1, it was poured into a polymerization mold for a flat plate to impregnate glass fibers, and heated in a heating bath at 85°C. Cured by polymerization. The polymerization and curing time at this time was 11.0 minutes, which was a very short time. Approximately 0.7wT obtained! In the resin plate having a thickness of n, no polymerization foaming was observed despite the short polymerization time, and the crazing resistance was also good.

Furthermore, no change in appearance was observed even in an accelerated exposure test of 100 screams. Further, the bending strength was 1640k9'd, which was sufficient. Example 4 A 50% toluene solution of 0.14% di-1s0-butylperoxydicarbonate as a polymerization initiator was added to the syrup obtained in Example 1 (0.30% of the dicarbonate was added to the syrup obtained in Example 1 for 10 parts of the syrup). x 10-3 mol parts) and 0.7% divinylbenzene as a polyfunctional unsaturated monomer and degassed under reduced pressure were mixed and dissolved in a polymerizable liquid composition in the same manner as in Example 1. It was injected into a mold to impregnate glass fibers, and polymerized and cured in a heating bath at 85°C.

The polymerization and curing time at this time was extremely short at 12.0 minutes. About 1? In spite of the short polymerization time, no polymerization foaming was observed in the resin plate having a thickness of 100 mL, and the crazing resistance was also good.

Further, no change in appearance was observed even in an accelerated exposure test of 100 ctf. Example 5 To the syrup obtained in Example 1, 0.52% of a 50% dioctyl phthalate solution of di-2-ethylhexyl peroxydicarbonate was added as a polymerization initiator (0.52% of the same dicarbonate was added to the syrup obtained in Example 1 for 10 parts of syrup). A polymerizable liquid composition obtained by mixing and dissolving .75 x 10-3 mole parts) and 1.2% of tetraethylene glycol dimethacrylate as a polyfunctional unsaturated monomer and degassing under reduced pressure was prepared in the same manner as in Example 1. The mixture was poured into a flat plate polymerization mold to impregnate glass fibers, and polymerized and cured in a heating bath at 85°C.

The polymerization curing time at this time was 8.0, which was a very short time. About 1Wr obtained! In the resin plate having a thickness of n, no polymerization foaming was observed despite the short polymerization time, and the crazing resistance was also good.

Further, no change in appearance was observed even in an accelerated exposure test of 10 (4) hours. Example 6 To the syrup obtained in Example 2, 0.0% of a 50% solution of di-Sec-butyl peroxydicarbonate in dibutyl phthalate was added as a polymerization initiator.
146% (0.32 x 10-3 parts by mole of dicarbonate per 10 parts by weight of syrup) and 0.8 parts of ethylene glycol dimethacrylate as a polyfunctional unsaturated monomer.
% was mixed and dissolved and degassed under reduced pressure, and in the same manner as in Example 1, it was injected into a polymerization mold for a flat plate, impregnated into glass fibers, and polymerized and cured in a heating bath at 85°C.

At this time, the polymerization curing time was 15.0 minutes, which was a very short time. The obtained resin plate having a thickness of about 1 mm showed no polymerization foaming despite the short polymerization time, and also had good crazing resistance.

Furthermore, no change in appearance was observed even in an accelerated exposure test of 100°C. Reference Example 1 0.15% of bis(4-tertiarybutylcyclohexyl) peroxydicarbonate was added to the syrup of Example 2 as a polymerization initiator (0.38 x 10-3 parts by mole per 10 parts by weight of the syrup). A polymerizable liquid composition prepared by mixing and dissolving 1.0% of tetraethylene glycol dimethacrylate as a polyfunctional unsaturated monomer and degassing under reduced pressure was placed in a polymerization mold for a flat plate in the same manner as in Example 1. It was injected to impregnate glass fibers and polymerized and cured in a 98°C heating bath.

At this time, the polymerization curing time was 13. It was a very short time. However, polymerization foaming was observed in the obtained resin plate with a thickness of about 1 inch, and even if the amount of polymerization initiator was appropriate, polymerization foaming occurred when the heating curing temperature exceeded the range of the present invention. This is not desirable because it causes

Reference Example 2 The syrup of Example 2 was added with an appropriate amount of bis(4-tertiarybutylcyclohexyl)pero7oxydicarbonate as a polymerization initiator and 1.2% of ethylene glycol dimethacrylate as a polyfunctional unsaturated monomer. A polymerizable liquid composition obtained by mixing and dissolving and degassing under reduced pressure was injected into a polymerization mold for a flat plate in the same manner as in Example 1, impregnated into glass fibers, and polymerized and cured to obtain the results shown in Table 3. Ta.

About 1T obtained! No polymeric foaming was observed in any of the 1 m thick resin plates.

However, from Table 3, when the amount of polymerization initiator is less than the range of the present invention, or even when the amount of polymerization initiator is appropriate but the heating curing temperature is lower than the range of the present invention, the polymerization curing time is longer. This is not preferable because productivity decreases over time. Reference Example 3 A 50% dibutyl phthalate solution of D-Sec-butyl peroxydicarbonate as a polymerization initiator was added to a syrup prepared by dissolving 10% of methacrylic resin (trade name Sumipetsu BMHL, manufactured by Sumitomo Chemical Industries, Ltd.) in methacrylate. 23% (0.49 x 10-3 mol parts of dicarbonate per 100 parts by weight of syrup) and 0.8% of ethylene glycol dimethacrylate as a polyfunctional unsaturated monomer were mixed and dissolved and degassed under reduced pressure. The resulting polymerizable liquid composition was poured into a flat plate polymerization mold to impregnate glass fibers in the same manner as in Example 1, and polymerized and cured in a heating bath at 85°C.

At this time, two steps were required for polymerization and curing time. Obtained about 1
A resin plate having a thickness of T$1 is polymerized and foamed, and even if the amount of polymerization initiator is appropriate, if the polymerization rate of the syrup is low, the polymerization curing time becomes long and polymerization and foaming occurs, which is not preferable.

Reference Example 4 In Example 3, the polymerizable liquid composition except for trimethylolpropane triacrylate, which is a polyfunctional unsaturated monomer, was polymerized and cured in the same manner as in Example 3.

When the obtained resin plate having a thickness of about 0.7 mm was immersed in ethyl acetate for one hour, numerous crazings occurred on its surface.

On the other hand, when the bending strength of the obtained resin plate was measured, it was 129
I lowered 0k91d. Further, when an accelerated exposure test for 100 screams was conducted, the resin plate turned white. ) Reference Example 5 Using the same stirred tank reactor as in Example 1, methyl methacrylate monomer containing 0.12% azobisdimethylvaleronitrile was prepared with an average residence time of 2. Prepolymerization was carried out in the same manner as in Example 1, except that the polymer was fed continuously so as to avoid confusion.The number average degree of polymerization of the polymer in the syrup with a polymerization rate of 30% and a viscosity of 8 poise at 25°C was 450. The weight average degree of polymerization was 945.

Therefore, the polydispersity of the polymerization degree distribution is 2.10. To this syrup, 0.1% bis(4-l tert-butylcyclohexyl) peroxydicarbonate was added as a polymerization initiator.
% (0.25 molar parts per 10 heel weight parts of the syrup) and 0.5% ethylene glycol dimethacrylate as a polyfunctional unsaturated monomer are mixed and dissolved and degassed under reduced pressure to form a polymerizable liquid. The composition was poured into a polymerization mold for a flat plate to impregnate glass fibers in the same manner as in Example 1, and polymerized and cured in a heating bath at 80°C.

The polymerization curing time at this time was 14. It was a very short time. Although no polymeric foaming was observed in the obtained resin plate with a thickness of about 1 Tmm, when the resin plate was immersed in ethyl acetate for 1 minute, numerous crazes were generated on its surface.

On the other hand, when the bending strength of the obtained resin plate was measured, it was 126
It was as low as 0k91cIt.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between the number of molar parts of dialkyl peroxydibonate per 100 parts by weight of the ship in the range of the present invention and the heating curing temperature.

Claims (1)

[Scope of Claims] 1. Dialkyl peroxide as a polymerization initiator is added to a syrup containing methyl methacrylate as a main component and a polyfunctional unsaturated monomer having two or more unsaturated groups and a polymerization rate of 15 to 35% by weight. Glass fibers are impregnated or mixed with a polymerizable liquid composition in which oxydicarbonate (each alkyl group has 3 to m carbon atoms) is dissolved, and then heated and cured. The relationship between the number of moles of a certain dialkyl peroxydicarbonate per 100 parts by weight of the syrup and the heat curing temperature (°C) is given by points A (5 x 10^-^5, 90) and B (1.5 x 10) in Figure 1. ^
-^3,90), C(1.5×10^-^3,70),
D (1.7 x 10^-^4, 70), E (5 x 10^-
^5, 85) A method for producing a glass fiber reinforced resin board, characterized by polymerizing and curing it under conditions within a closed region formed by connecting each point of (5, 85) with a straight line. 2. The number average degree of polymerization of the polymer in the syrup is 500 or more,
A patent claim characterized in that the weight average degree of polymerization is 2500 or less, and the polydispersity of the polymerization degree distribution expressed by the ratio of the weight average degree of polymerization to the number average degree of polymerization of the polymer is 2.5 or less Scope 1. Method of description. 3. The polyfunctional unsaturated monomer having two or more unsaturated groups contained in the syrup is ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, decamethylene glycol diacrylate. , trimethylolpropane triacrylate, trimethylolpropane triacrylate, allyl acrylate, diallyl acrylate, crotyl acrylate,
Mesaryl acrylate, tetramethylolmethane triacrylate, ethyne glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, decamethylene glycol dimethacrylate, trimethylolpropane dimethacrylate, trimethylolpropane trimethacrylate, allyl Methacrylate, diallyl methacrylate, cucatyl methacrylate, mesaryl methacrylate, tetramethylolmethane trimethacrylate, divinylbenzene, triallyl isocyanurate, diallyl phthalate, diallyl isophthalate, diallyl terephthalate, diallylbenzene, diethyl glycol bisallyl carbonate, diallyl maleate, The method according to claim 1, wherein the at least one type selected from diallyl fumarate, diallylitaconate, divinyl ether, and dimesalyl ether is present in an amount of 0.2 to 10% by weight based on the total weight of the syrup. . 4 The polymerization initiator dialkyl peroxydicarbonate is diisopropyl peroxydicarbonate, di-
n-butylperoxydicarbonate, di-iso-butylperoxydicarbonate, di-sec-butylperoxydicarbonate, dicyclohexylperoxydicarbonate, di-2-ethylhexylperoxydicarbonate, di-ethoxyethylperoxy The method according to claim 1, wherein the material is at least one selected from dicarbonate, di-3-methoxybutyl peroxydicarbonate, and bis(4-tert-butylcyclohexyl) peroxydicarbonate.