JPS6237661B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides a resin syrup with a specific and new composition whose main component is acrylic acid, methacrylic acid, or an ester of acrylic acid or methacrylic acid represented by methyl methacrylate (hereinafter simply referred to as acrylic acid or its ester). rate
A chemical glass fiber reinforced resin molded board with excellent transparency, light transmittance, mechanical properties, and surface smoothness by impregnating it with chemical glass fiber of 1.515 to 1.520 and hardening it, especially a roof board for a greenhouse. The present invention relates to a method for inexpensively manufacturing a chemical glass fiber reinforced resin molded plate suitable for side wall plates and the like. Conventionally, glass fiber-reinforced resin molded products obtained by impregnating glass fibers with a resin containing methyl methacrylate as a main component and curing the resin are often used as plate-shaped molded products outdoors, and in particular,
A copolymer of methyl methacrylate and vinyl aromatic hydrocarbon is used to obtain a transparent molded product by combining the refractive index of the resin impregnated into the glass fiber with the refractive index of the glass constituting the glass fiber. The vinyl aromatic hydrocarbon polymer has a refractive index of about 1.49 that the acid methyl polymer originally has.
There is a method of correcting with a high refractive index of 1.58 to 1.60 to match the refractive index of glass fiber. [For example, RB
Beevers, Trans.Faraday Soc., 58 1465
(1962)]. As one of them, Japanese Patent Publication No. 15909/1986 discloses an acrylonitrile-styrene copolymer containing 17 to 40 mol% of acrylonitrile in a methyl methacrylate monomer or a monomer mixture containing methyl methacrylate as a main component. Has a dissolved composition, 20
It is stated that a transparent glass fiber reinforced resin composition with improved heat resistance can be obtained by impregnating glass fibers with a methyl methacrylate syrup composition having a viscosity of 0.1 to 50 poise at °C. However, in order to obtain a transparent glass fiber-reinforced resin composition, the refractive index of the glass fiber must match the refractive index of the resin, and there are many types of glass fiber due to their raw material composition. It is a well-known fact that they have different refractive indices. Therefore, unless a specific glass fiber having the same refractive index is used for a resin composition having a specific composition as disclosed in the above-mentioned publication, it is impossible to obtain a transparent glass fiber reinforced resin composition. I can't. However, even if the refractive index of the resin could be made to match the refractive index of glass fiber, the vinyl aromatic carbons remaining in the resin syrup obtained by partially copolymerizing methyl methacrylate and vinyl aromatic hydrocarbons Since hydrogen has a slow reaction rate, it takes a long time to harden during the molding process, which is a major drawback in improving productivity. Furthermore, in the production of conventional glass fiber-reinforced synthetic resin molded plates, alkali-free glass fibers with high stability as glass have been used exclusively, but alkali-free glass also has high production costs, so There is an increasing demand for manufacturing glass fiber-reinforced synthetic resin molded plates using alkali-containing glass known as chemical glass. The present invention has been made for the purpose of solving these many problems and establishing a method for manufacturing reinforced synthetic resin molded plates using chemical glass fibers. -50% by weight and 90-50% by weight of vinyl aromatic hydrocarbons with a viscosity average molecular weight of 30,000-100,000
or an acrylonitrile/vinyl aromatic hydrocarbon copolymer with a viscosity average molecular weight of 30,000 to 100,000 modified with a small amount of a polyfunctional monomer.
50% by weight of acrylic acid or methacrylic acid or their esters or mixtures thereof.
A chemical glass having a refractive index of 1.515 to 1.520 is mixed with a resin syrup of a specific and new composition, in which the content of vinyl aromatic hydrocarbons in the syrup is in the range of 75 to 50% by weight and is 20 to 35% by weight. By impregnating the fibers, it was possible to produce a chemical glass fiber-reinforced resin molded plate with excellent mechanical properties such as transparency, light transmittance, and bending strength, and surface smoothness. The chemical glass fiber used in the present invention is a glass fiber made of so-called alkali-containing (also referred to as C glass) containing an alkali metal oxide, and has a refractive index of 1.515 to 1.520, and is reinforced with the glass fiber. The transparent molded synthetic resin board has particularly excellent light transmittance, mechanical properties, and surface smoothness, and therefore exhibits particularly excellent performance as a roof board, side wall board, etc. of a greenhouse. In the resin syrup used in the present invention, the concentration of the acrylonitrile/vinyl aromatic hydrocarbon copolymer in the resin syrup is 25 to 50% by weight, but if it exceeds 50% by weight, the resin syrup The viscosity of the resin syrup increases, making it difficult to handle, so it is necessary to avoid creating a resin syrup with an unnecessarily high concentration. On the other hand, in order to bring the refractive index of the resin closer to the refractive index of chemical glass fiber, 1.515 to 1.520, and to avoid the opacity of the glass fiber reinforced resin molded plate caused by the difference between the refractive index of the glass fiber and the refractive index of the resin, syrup The vinyl aromatic hydrocarbon component must be contained in the amount of 20 to 35% by weight.
As a result, the concentration of acrylonitrile/vinyl aromatic hydrocarbon copolymer was set to 25 to 50% by weight,
The refractive index of the final cured resin molded product obtained from this resin syrup containing 20 to 35% by weight of a vinyl aromatic hydrocarbon component is within the range of 1.510 to 1.530. The chemical glass fiber reinforced resin molded product has extremely excellent transparency because the glass fiber has a refractive index of 1.515 to 1.520. For example, in a resin syrup used for glass fibers, the ratio of acrylonitrile to styrene is 50:
The refractive index of a 40% by weight solution of a copolymer consisting of 50% (i.e., the styrene content is 20% by weight) is approximately 1.510, and the ratio of acrylonitrile to styrene is
The refractive index of a 25% by weight solution of a copolymer consisting of 10:90 (i.e. the styrene content is 23% by weight) is
The refractive index of the resin of a 50% by weight solution of a copolymer having a ratio of acrylonitrile and styrene of 30:70 (that is, the styrene content is 35% by weight) is about 1.513, and both are used in the present invention. The refractive index of chemical glass fiber is 1.515 to 1.520. In the present invention, chemical glass fibers are impregnated with the resin syrup prepared in this manner, and then cured and molded.In order to effectively impregnate the glass fibers, the viscosity of the resin syrup is adjusted to 3 to 7 poise at room temperature. Acrylonitrile/vinyl aromatic The viscosity average molecular weight of the group hydrocarbon copolymer is suppressed within the range of 30,000 to 100,000 to satisfy high solubility of the copolymer in the resin syrup, and the concentration of the copolymer in the resin syrup is set to 25 to 50. It needs to be in weight%. This is because the resin syrup for glass fiber impregnation is 3.
If the viscosity is less than 7 poise, the resin syrup will flow out during the impregnation operation, making it difficult to control the thickness of the molded plate as a product.If the viscosity is 7 poise or higher, the resin syrup will flow out during the impregnation operation. This is because not only is it difficult to remove the air bubbles mixed in, but also the adhesion between the glass fiber and the resin becomes insufficient, making it difficult to obtain a molded plate with sufficient strength. Furthermore, when an acrylonitrile/vinyl aromatic hydrocarbon copolymer dissolved in acrylic acid or its ester has a viscosity average molecular weight of 30,000 or less in the resin syrup, this copolymer has the properties as a so-called polymer. However, if a copolymer with a viscosity average molecular weight of 100,000 or more is used, the dissolution operation for dissolving the copolymer in acrylic acid or its ester takes a long time. Not only is this necessary, but the solubility of the copolymer is poor, making it difficult to obtain a uniformly dissolved resin syrup, and not only does the apparent strength of the product, the molded plate, decrease.
When impregnating glass fiber with resin syrup and curing it, the amount of monomer in the resin syrup is large,
As a result, the volumetric shrinkage rate associated with polymerization is high, and the surface of the product molded plate is not smooth, and the glass fibers are lifted up and visible. Since the amount of monomer present is large, the amount of heat generated during curing is large, resulting in the problem that the curing temperature must be kept low and the curing time must be prolonged. The vinyl aromatic hydrocarbon used in the present invention is a hydrocarbon having a structure in which one vinyl group is directly connected to an aromatic ring, and can be copolymerized with acrylonitrile such as styrene, α-methylstyrene, vinyltoluene, vinylxylene, etc. vinyl aromatic hydrocarbons can be used. In addition, the monomers of acrylic acid, methacrylic acid, or their esters that dissolve the acrylonitrile/vinyl aromatic hydrocarbon copolymer include acrylic acid, methyl methacrylate, butyl methacrylate,
Hydroxyethyl acrylate, methyl methacrylate, and the like can be used alone or as a mixture of several of these, and among these, methyl methacrylate is the most practical. Furthermore, in the present invention, the curing time of the resin syrup impregnated into glass fibers is determined by adding a catalyst such as benzoyl peroxide, acetyl peroxide, and t-butyl peroxypivalate to the resin syrup having the above-mentioned composition. Or for example about 50-80℃
It is also possible to increase the polymerization rate by applying measures to increase reactivity, such as raising the temperature to By adding a polyfunctional monomer to the syrup, it is possible to promote the gel effect during the curing process, and it is possible to apply general resin curing acceleration methods such as actively carrying out a three-dimensional crosslinking reaction. It is. Commonly used chain transfer agents include alkyl mercaptans such as n-dodecyl mercaptan, isopropyl mercaptan, and n-butyl mercaptan, as well as thiophenol, thiocresol,
There are sulfur compounds having active hydrogen such as allyl mercaptan such as thionaphthol, thioglycolic acid or its ester, and it is effective to use them in an amount of about 0.1 to 1.0% by weight based on 100% by weight of the monomer. Furthermore, as polyfunctional monomers, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, ethylene dimethacrylate,
These include ethylene glycol dimethacrylate, ethylene glycol diacrylate, trimethylol ethane triacrylate, 1,3-butylene dimethacrylate, glycidyl methacrylate, divinylbenzene, triallyl cyanurate, triallyl isocyanurate, among others 1,3-butylene dimethacrylate, The use of range methacrylate, ethylene dimethacrylate, and trimethylolpropane trimethacrylate is extremely effective in accelerating curing. Generally, the curing time of a resin syrup containing about 5% by weight of these polyfunctional monomers as a crosslinking agent is shortened to about 2/3 to 1/2 of the curing time of a resin syrup that does not contain any crosslinking agent. has been confirmed. However, if the amount of the polyfunctional monomer added exceeds about 2% by weight, the transparency of the resulting molded plate tends to be impaired, so it is necessary to keep the amount added to about 2% by weight or less. However, while the first claimed invention utilizes an unmodified acrylonitrile/vinyl aromatic hydrocarbon copolymer, the second claimed invention uses a resin syrup. As an acrylonitrile/vinyl aromatic hydrocarbon copolymer, a modified acrylonitrile/vinyl aromatic hydrocarbon copolymer is modified with a small amount of a polyfunctional monomer of 0.05 to 0.2 parts by weight based on 100 parts by weight of the total amount of acrylonitrile and vinyl aromatic hydrocarbon. By using a hydrocarbon copolymer and adding a polyfunctional monomer to a resin syrup containing this copolymer as a constituent component, impregnating glass fiber with this and performing a curing process, transparency can be achieved. This makes it possible to manufacture superior molded plates more efficiently. Modified acrylonitrile with a viscosity average molecular weight of 30,000 to 100,000 modified with a polyfunctional monomer.
The production of vinyl aromatic hydrocarbon copolymer requires the total amount of acrylonitrile and vinyl aromatic hydrocarbon to be 100%
When using a polyfunctional monomer at a ratio of 0.1 to 0.2 parts by weight, the polyfunctional monomer is added at the initial stage of polymerization, the reaction is stopped at a polymerization rate of about 30%, and the desired product is obtained. Barrel modified acrylonitrile・
The vinyl aromatic hydrocarbon copolymer is recovered by precipitation with methanol, or a polyfunctional monomer is added at a polymerization rate of 70 to 90% to complete the polymerization and the modified acrylonitrile/vinyl aromatic hydrocarbon copolymer is recovered. It is preferable to recover the polymer, and if 0.05 to 0.1 part by weight of polyfunctional monomer is used per 100 parts by weight of acrylonitrile and vinyl aromatic hydrocarbon, the polyfunctional monomer can be recovered at an early stage of the polymerization. Preferably, the functional monomer is added, the polymerization is completed, and the modified acrylonitrile/vinyl aromatic hydrocarbon copolymer is recovered. If the polyfunctional monomer added in the production of the modified acrylonitrile/vinyl aromatic hydrocarbon copolymer is less than 0.05 part by weight per 100 parts by weight of the total amount of acrylonitrile and vinyl aromatic hydrocarbon, the modification effect will not be achieved. If the amount exceeds 0.2 parts by weight, the transparency of the resulting molded plate will decrease. In addition, when adding a polyfunctional monomer as a crosslinking agent to a resin syrup using a modified acrylonitrile/vinyl aromatic hydrocarbon copolymer, the solubility of the polymer product remains unchanged even if the amount added increases. It was confirmed that the degree of shortening of the curing time increases depending on the amount added, and the degree of shortening is even higher than when curing is done by post-adding a polyfunctional monomer to an unmodified copolymer. Almost no effect was observed on the transparency of the molded plate. However, if the amount of the post-added polyfunctional monomer as a crosslinking agent exceeds about 5% by weight,
As explained in the case of using an unmodified copolymer, the resulting molded plate becomes brittle and stiff, so it is preferable to keep the amount added to about 5% by weight at most. The amount of polyfunctional monomers that can be added can be increased in the case of unmodified copolymers by the crosslinking reaction between the dissolved polymer and resin syrup caused by the post-addition of polyfunctional monomers. Phase separation between the polymer of acrylic acid or its ester produced by polymerization curing is likely to occur, and transparency is impaired due to this, but modified acrylonitrile/vinyl aromas that have been modified with polyfunctional monomers in advance This is thought to be because when a group hydrocarbon copolymer is used, phase separation upon subsequent addition of a polyfunctional monomer is suppressed. The polyfunctional monomers that can be used to produce the modified acrylonitrile-vinyl aromatic hydrocarbon copolymer include the same polyfunctional monomers for post-resin syrup addition described above; The functional monomer and the polyfunctional monomer for post-addition may be of the same type or may be of different types. According to the invention of claim 2, in which a polyfunctional monomer is post-added to the resin syrup produced using this unmodified copolymer, the curing time is compared to that in the case of claim 1. As a result, the curing time can be further shortened, and the productivity of glass fiber-reinforced synthetic resin plates with transparency, light transmittance, mechanical properties, and surface smoothness can be greatly improved. becomes. In addition, when producing a glass fiber reinforced resin molded plate by the method of the present invention described above, the amount of chemical glass fiber to the resin syrup is 100% of the resin syrup.
From the viewpoint of mechanical strength of the molded plate, it is preferable to use it in a ratio of about 20 to 30 parts by weight. The following describes the synthesis of resin syrup, which is the basis of the method for producing glass fiber-reinforced resin molded products of the present invention, and the glass fibers cured by adding 1 part by weight of t-butyl peroxypipalate per 100 parts by weight of the resin syrup. The results of measuring the various properties of a molded plate without glass fibers are used as an example of syrup production, and the results of synthesizing a resin syrup using a conventional method and measuring the properties of a molded plate that does not contain glass fiber by curing the resin syrup are used as an example of syrup comparative production. The method for manufacturing a glass fiber reinforced resin molded plate according to the present invention will be described with reference to Examples. Examples Syrup Production Example 1 A monomer mixture consisting of 10 parts by weight of acrylonitrile and 90 parts by weight of styrene, 0.1 part by weight of t-butyl peroxybiparate as a polymerization initiator, and n-dodecyl mercaptan as a chain transfer agent.
0.6 parts by weight were charged into a reaction vessel and reacted at 60°C to create an acrylonitrile-styrene copolymer prepolymer with a viscosity average molecular weight of 70,000. 75 parts by weight of methyl methacrylate and 0.05 parts by weight of azobisisobutyronitrile as a polymerization initiator were added to 25 parts by weight of the obtained prepolymer, and these were reacted in a reaction vessel to achieve a polymerization rate of 31 to 33%. ,viscosity
A resin syrup of 5.5 poise (25°C) was obtained. Next, 1 part by weight of t-butyl peroxypivalate was added per 100 parts by weight of this resin syrup, poured into a flat mold, and cured by heating at about 65°C for 16 minutes. A 1 mm resin cured plate was obtained. Repeated experiments similar to this one confirmed that the resin syrup completely cured in 15 to 17 minutes. The obtained cured resin plate is translucent to the extent that it can be used as a transparent plate for practical purposes, and the light transmittance (%)
(350 mμ) 82-83, refractive index 1.513, bending strength (Kg/mm ² ) 10-12, and tensile strength (Kg/mm ² ) 5-7. In addition, in the series of experiments, the composition ratios of various monomers used to produce the resin syrup, the characteristics of the resin molded plate, etc. are specified in Table 1. Syrup Production Examples 2 to 4 A monomer mixture of acrylonitrile and styrene in the quantitative proportions shown in Table 1, 0.1 part by weight of t-butyl peroxypivalate as a polymerization initiator, and optionally a chain transfer agent. 0.1 to 0.8 parts by weight of n-dodecyl mercaptan is charged into a reaction vessel and reacted at 60°C to form acrylonitrile.
A prepolymer of styrene copolymer was prepared. 25 to 40 parts by weight of the obtained prepolymer, 75 to 60 parts by weight of methyl methacrylate, and optionally azobisisobutyronitrile as a polymerization initiator.
0.05 parts by weight was added and the mixture was reacted in a reaction vessel or the mixture was left to stand to obtain a resin syrup having a polymerization rate and viscosity as shown in Table 1. Next, 1 part by weight of t-butyl peroxypivalate was added per 100 parts by weight of each resin syrup, poured into a flat mold, and heated at about 65°C for the time indicated in Table 1. By doing so, a molded resin plate having a thickness of 1 mm and extremely excellent transparency was obtained. Syrup Comparative Production Examples 1 to 3 A monomer mixture of methyl methacrylate and vinyl aromatic hydrocarbon having the quantitative proportions shown in Table 2, and 0.05 parts by weight of azobisisobutyronitrile as a polymerization initiator. n as a chain transfer agent
Charge 0.6% by weight of dodecyl mercaptan into a reaction vessel and react at 80°C to determine the viscosity average molecular weight.
Obtained 50,000 monomer syrups. Next, add 1 part by weight of t-butyl peroxypivalate per 100 parts by weight of this monomer syrup, pour it into a flat mold as in syrup production examples 1 to 4, and heat it at about 65°C. A resin molded plate with a thickness of about 1 mm was obtained. The curing time required in this case is 30 minutes or more as shown in Table 2. Syrup Comparative Production Examples 4 to 5 Prepolymers of styrene homopolymers were obtained, mixed with methyl methacrylate in the quantitative proportions shown in Table 2, and optionally heated and reacted in a reaction vessel. , a resin syrup was obtained. Next, 1 part by weight of t-butyl peroxypivalate was added to each 100 parts by weight of each resin syrup, poured into a flat mold, and heated at about 65°C to form a resin with a thickness of about 1 mm. Got the board. The curing time required in this case can be shortened to about 15 to 20 minutes, as shown in Table 2.
The resin molded plates obtained are all cloudy due to phase separation between the dissolved polymer and the polymer of acrylic acid or its ester produced by polymerization and curing of the resin syrup, and the transparent resin molded plates are I can't get it. Syrup Comparative Production Example 6 20 parts by weight of an acrylonitrile-styrene copolymer having a molecular weight of 250,000 was dissolved in 80 parts by weight of methyl methacrylate and heated to obtain a resin syrup. This resin syrup has a composition similar to that of the resin syrup disclosed in Example 1 of Japanese Patent Publication No. 44-15909 mentioned above. From the obtained resin syrup, a resin molded plate having a thickness of about 1 mm was produced in the same manner as in Syrup Comparative Production Examples 4 and 5. The refractive index of the obtained resin molded plate was 1.505, and the surface smoothness and mechanical properties, especially the bending strength, were significantly reduced due to the high monomer content in the resin syrup.

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[Table] Next, the resin syrups obtained in Syrup Production Example 2 and Syrup Production Example 4 were prepared with a refractive index of 1.515.
A method for manufacturing a molded plate by impregnating chemical glass fibers with a molecular weight of 1.520 to 1.520 and curing the resin syrup, and the characteristics of the obtained chemical glass fiber reinforced resin molded plate will be explained. Production of glass fiber reinforced resin molded plate Polymer monomer resin syrup (A) obtained by adding 3 parts by weight of trimethylolpropane trimethacrylate to 100 parts by weight of the resin syrup obtained in Syrup Production Example 2, and the syrup obtained in Syrup Production Example 4 1 part by weight of t-butylperoxypivalate was added to each 100 parts by weight of the polymer monomer-based resin syrup (b), which was prepared by adding 3 parts by weight of trimethylolpropane trimethacrylate to 100 parts by weight of the resin syrup, After mixing well, a chopped strand of chemical glass fiber with a refractive index of 1.517 and a length of 5 cm was impregnated with this in a weight ratio of 1 part glass fiber to 4 parts resin syrup, and a spacer of 1 mm thickness was used to impregnate the chopped strand with the mixture. 65℃ while regulating
In case of (a), heat for 18 minutes and in case of (b), heat for 12 minutes,
After curing, post-curing was performed at 120° C. for 5 minutes to obtain the intended chemical glass fiber reinforced resin molded plate. The properties of the obtained resin molded plate were evaluated using resin syrup (a).
Table 3 shows the case where the resin syrup was used as Example 1, and the case where the resin syrup (B) was used as Example 2. Comparative Example 1 To 100 parts by weight of the monomer-based resin syrup obtained in Syrup Comparative Production Example 1, 1 part by weight of t-butyl peroxypivalate was added, mixed well, and the same as used in the previous example was added. A 5cm chopped strand of chemical glass fiber was impregnated with resin syrup at a weight ratio of 1 part glass fiber to 4 parts resin syrup, and while being regulated with a 1 mm thick spacer, 65
It took about 34 minutes or more to heat cure at ℃. Subsequently, post-curing was performed at 120°C for 5 minutes, and the third
A chemical glass fiber reinforced resin molded plate having the properties shown in the table was obtained. Comparative Example 2 1 part by weight of t-butyl peroxypivalate was added to 100 parts by weight of the polymer monomer resin syrup obtained in Syrup Comparative Production Example 6, mixed well, and impregnated into chemical glass fibers with a refractive index of 1.519. This was then cured at 56°C for 34 minutes to obtain a chemical glass fiber reinforced resin molded plate. The properties of the obtained resin molded plate are as shown in the column of Comparative Example 2 in Table 3, but while the refractive index of chemical glass fiber is 1.519, As shown, since the refractive index of the resin does not match 1.505 at all, glass fibers can be clearly observed, the molded plate has no transparency, and the glass fiber portion is raised and the surface smoothness is significantly reduced. Inferior. Furthermore, in Comparative Example 2, which uses a copolymer with a high molecular weight of 250,000, the monomer content in the resin syrup is high, and for example, when the curing temperature is set to 65°C, curing can be completed in 23 minutes. However, the foaming phenomenon occurred significantly during the curing process, making it impossible to obtain a transparent and smooth molded plate.

[Table] In each of the above syrup production examples, syrup comparison production examples, examples of the present invention, and comparative examples with the present invention, 1. The viscosity average molecular weight of the polymer was measured using an Ostwald capillary viscometer, and the methyl methacrylate - Styrene type is the value measured by dissolving it in benzene (25℃), methyl methacrylate-styrene-acrylonitrile type is dissolved in dimethylformamide (25℃). 2 Polymerization rate is the value measured by precipitation with acetone (good solvent) - methanol (poor solvent). 3 The viscosity is measured using a BM type standard viscometer (manufactured by Tokyo Keiki Co., Ltd.) No.
2. Values based on rotor, 30 rpm, 4. Curing time is 100 parts by weight of each syrup, t.
Curing time at 65°C using a DSC (differential scanning calorimeter, manufactured by PerkinElmer) to which 1 part by weight of butyl peroxypivalate was added; 7. The refractive index is the value at 25°C using an Atsube refractometer (manufactured by Shimadzu Corporation). 8. The bending strength is the tensilon (Toyo Baldwin) test piece of a test piece with a width of 20 mm, a span of 50 mm, and a thickness of 1 mm. 9 tensile strength is 5 mm width (center width 3 mm), length 100
The weather resistance is the result of visual observation of hue change in a 400-hour exposure test using a Suga Test Instruments weather meter. As described in detail above, a vinyl aromatic hydrocarbon copolymer is dissolved in acrylic acid or methacrylic acid, an ester thereof, or a mixture thereof having a specific composition as described in the claims of the present invention. Since the resin syrup has a refractive index very close to the refractive index of the chemical glass fiber (1.515 to 1.520), it is not only possible to obtain an extremely transparent molded plate in a short time, but also has excellent light transmittance and surface properties. , and mechanical properties, especially as revealed in Examples 1 and 2 in Table 3, the bending strength is considerably improved compared to the conventional example shown in Comparative Examples 1 and 2, and the material has a high degree of flexibility and flexibility. This is a chemical glass fiber reinforced resin that can be used for curved structural parts such as semicircular greenhouses and house roofs, and can withstand strong bending during fitting. This made it possible to produce molded plates in a short time and at low cost. That is, in the composition of the resin syrup disclosed in Japanese Patent Publication No. 44-15909, which is shown as the prior art at the beginning of this specification, the refractive index of the chemical glass fiber of the present invention does not match that of the chemical glass fiber of the present invention, and a transparent molded plate is obtained. It is not possible. This means that the resin syrup shown in Syrup Comparison Production Example 6 in Table 2 is
- It has a composition almost similar to the resin syrup disclosed in No. 15909, and even though a molded plate made from the resin syrup alone is transparent, its refractive index is 1.505, which is the refractive index of the chemical glass fiber of the present invention. It is clear from Table 2 that the difference is 1.515 to 1.520, and this fact is confirmed by the molded plate obtained by impregnating chemical glass fiber with the resin syrup of Syrup Comparative Production Example 6, that is, Table 3 Comparative Example 2. This is also clear from the fact that the molded plate shown in Figure 1 lacks transparency, and yet the syrup comparative production example 6
When molding the molded plate of Comparative Example 2 using the resin syrup of 56°C, foaming occurred during the curing process and a transparent and smooth molded plate could not be obtained. Whereas curing molding is required at low temperatures and for a long time, such as 34 minutes, when using the resin syrup of the present invention, transparent and smooth molded plates can be molded in a short time at a temperature of 65°C. can be,
It is clear that the bending strength of the obtained molded plate is also improved by about 10%, which has an extremely large effect on improving productivity.

Claims (1)

[Claims] 1. An acrylonitrile/vinyl aromatic hydrocarbon copolymer comprising 10 to 50% by weight of acrylonitrile and 90 to 50% by weight of a vinyl aromatic hydrocarbon and having a viscosity average molecular weight within the range of 30,000 to 100,000. Polymer 25~
50% by weight and 75-50% of acrylic acid or methacrylic acid or their esters or mixtures thereof
A chemical glass fiber having a refractive index of 1.515 to 1.520 is impregnated with a resin syrup consisting of 20% to 35% by weight, in which the content of vinyl aromatic hydrocarbons in the resin syrup is adjusted to 20 to 35% by weight. A method for manufacturing a glass fiber-reinforced resin molded plate, the method comprising: followed by a curing treatment. 2 100 parts by weight of a copolymer of 10 to 50% by weight of acrylonitrile and 90 to 50% by weight of vinyl aromatic hydrocarbon is modified with 0.05 to 0.2 parts by weight of a polyfunctional monomer, and the viscosity average molecular weight is 30000～
A resin syrup consisting of 25 to 50% by weight of a modified acrylonitrile/vinyl aromatic hydrocarbon copolymer within the range of Also, the content of vinyl aromatic hydrocarbons in the resin syrup is 20 to 35% by weight.
A method for manufacturing a glass fiber-reinforced resin molded plate, characterized by further adding a polyfunctional monomer to a resin syrup adjusted to 1.515 to 1.520, impregnating it into chemical glass fibers with a refractive index of 1.515 to 1.520, and then performing a curing treatment. .