JPS61127726A - Thermosetting preform - Google Patents

Abstract

PURPOSE:To provide the titled preform composed of specific amounts of a carboxyl-containing vinyl monomer, a glycidyl-containing vinyl monomer and other copolymerizable monomer, containing specific amount of residual unreacted monomers, and having a specific second-order transition point and excellent transparency, etc. CONSTITUTION:The objective preform having a residual unreacted monomer content of <20% and a second-order transition point of <=120 deg.C can be produced by (1) mixing (A) 4-30wt% one or more carboxyl-containing vinyl monomers (e.g. methacrylic acid), (B) 4-965 one or more glycidyl-containing vinyl monomers (e.g. beta-methyl-glycidyl acrylate) and (C) 0-92% other copolymerizable monomers, (2) adding a polymerization initiator (e.g. azobisisobutyronitrile) and a chain transfer agent (e.g. n-dodecylmercaptan), and (3) reacting the components e.g. by bulk-polymerization. USE:For glazings and various optical parts, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a novel transparent thermosetting preform. The present invention also seeks to provide a thermosetting preform suitable for producing various optical parts such as glazings, eye lenses, and prisms that require transparency, heat resistance, and chemical resistance. It is something to do. Furthermore, the present invention also relates to a method for producing a heat-resistant and chemical-resistant molded article with high productivity from the preformed article.

[Conventional technology]

Traditionally, inorganic glasses have been mainly used for glazing purposes, eyeglasses, and various optical components, and in recent years, thermoplastic resins such as polycarbonate, polystyrene, and polymethyl methacrylate, and those described in U.S. Patent No. 2,542,386 have been used. Diethylene glycol bisallyl carbonate resin, which is a thermosetting resin, is being used.

[Problem that the invention seeks to solve]

Inorganic glasses conventionally used for glazing, eyeglasses, and various base parts have excellent heat resistance, chemical resistance, and properties, but have the drawbacks of high specific gravity and easy breakability. On the other hand, among the materials used as plastic materials, thermoplastic resins such as polycarbonate, polystyrene, and polymethyl methacrylate are lightweight and have excellent processability, but have the disadvantage of poor heat resistance and chemical resistance. Furthermore, although 0R-39, which is a thermosetting resin, has relatively good heat resistance and chemical resistance, the polymerization method is a so-called one-casting method in which monomers are injected into a mold and then heat cured. However, it has the drawbacks of poor productivity and poor dimensional stability due to volumetric shrinkage during curing. The present invention overcomes the drawbacks of conventionally used plastic materials and provides a transparent thermosetting preform that has excellent heat resistance and chemical resistance and is suitable for producing transparent resins. It is something.

[Means for solving problems]

The inventors of the present invention have developed a technology that has excellent heat resistance and chemical resistance, which are the advantages of thermosetting resins, and excellent transparency, without sacrificing the advantages of conventional thermoplastic resins, such as mass production and excellent moldability. We have been making every effort to study materials suitable for making resins and methods for their bottom shapes, but using transparent thermosetting preforms such as those shown below, we can achieve the desired transparency with excellent heat resistance and chemical resistance. discovered that it was possible to produce polyester resin with high productivity, and completed the present invention.

In the present invention, in order to achieve the above-mentioned objective t-, the carboxyl group-containing vinyl monomer, the glycidyl group-containing vinyl monomer, and other copolymerizable monomers are each used in 4 to 4 to The preform contains less than 20% of monomer remaining unreacted in the preform, and has a secondary transition point of 120°C or less. The present invention relates to transparent, thermosetting preforms. Such a preformed body of the present invention t150°C
By heating and molding at a temperature above and thermosetting, a molded product with good dimensional accuracy can be obtained. The glycidyl group-containing monomer, which is the crosslinkable monomer used in the preform of the present invention, and the carboxyl group-containing monomer, which is the curing agent, hardly undergo a curing reaction at temperatures below 120°C.

For this reason, the transparent thermosetting prepolymer is solid at room temperature and easy to handle, and at temperatures above 150°C, it softens and becomes a thermoplastic resin at the initial stage of heating, but the thermosetting reaction progresses over time. It has the property of curing. Furthermore, by selecting all the molding conditions, it is possible to apply the shaping method of thermoplastic resin even though it is a thermosetting resin. This dramatically improves productivity.90 Specific examples of the carboxyl group-containing vinyl monomer constituting the transparent thermosetting preform of the present invention include methacrylic acid, acrylic acid, itabonic acid, and crotonic acid. can be given. Specific examples of the glycidyl group-containing vinyl monomer include glycidyl acrylate, glycidyl methacrylate, β-methylglycidyl acrylate, and β-methylglycidyl methacrylate.

In particular, β-methylglycidyl group-containing monomers have relatively good thermal stability of their epoxy groups and undergo a curing reaction with carboxyl groups in the molding temperature range, so they are suitable as monomers for the preform of the present invention. be. Specific examples of copolymerizable monomers used in addition to these crosslinkable monomers include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, 11iIo-propyl methacrylate, n-butyl methacrylate, j , so-butyl methacrylate, 5ec-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate,
Methyl acrylate, ethyl acrylate-1'% n-
Examples include, but are not limited to, propyl acrylate, 1so-propyl acrylate, n-butyl acrylate, styrene, α-methylstyrene, triple oleoethyl methacrylate, and hentafluoro-apropyl methacrylate.

However, if the carboxyl group-containing monomer and glycidyl group-containing monomer components contained in the preform are 4 weight drops or the proportion of the glycidyl group-containing monomer is 96 or more, When thermally cured at a temperature of 150°C or higher, the crosslinking density becomes too low, resulting in problems such as insufficient heat resistance and chemical resistance, or foaming, which impairs the final transparency. . - If the content of carboxyl group-containing monomer exceeds 30% by weight of gold, hygroscopicity increases and dimensional stability deteriorates. Therefore, the content of the carboxyl group-containing monomer and the glycidyl group-containing monomer contained in the composition is 4 to 30% by weight and 4 to 96% by weight, preferably 7 to 25% by weight and 7 to 80% by weight, respectively. shall be. or,
If the monomer remaining in the preform is 20% by weight or more, the softening temperature of the final molded product will be too low,
The adhesiveness of the resin increases, and when handling the preform, it deforms and becomes difficult to work with. Therefore, it is preferable that the amount of monomer remaining in the composition is 20% by weight.

The transparent thermosetting resin preform of the present invention is preferably produced by a bulk weighting method. As the initiator used for polymerization, radical initiators in the intermediate temperature range such as azobisisobutyronitrile, azobisγvaleronitrile, benzoyl peroxide, and lauryl peroxide are preferable.

As the chain transfer agent, n-dodecylmercaptan, n-octylmercaptan, n-butylmercaptan, and t-butylmercaptan are preferably used. The amount of the initiator and the continuous g-transfer agent to be added and the loading conditions are appropriately set based on conventional technology, taking into consideration the combination of monomers, so that the amount of residual monomer is less than 20"Xt. In order to keep the thermosetting reaction between the carboxyl group-containing monomer and the glycidyl group-containing monomer as low as possible, the polymerization temperature is preferably set to 100°C or less.

As a method for obtaining a final molded body from the transparent thermosetting preform of the present invention, for example, the preform is cut in advance into a size corresponding to the size of the desired molded body,
After rapidly heating with an infrared heater etc. to 150℃ or more,
The preform is molded by being pressed into a mold, or the preform is sandwiched between molds heated to 150° C. or higher and molded by pressure. At this time, a thermosetting reaction proceeds simultaneously and shaping is performed, but unlike curing from a monomer such as in the "one-casting method", the volumetric shrinkage accompanying polymerization is extremely small, resulting in molded products with good dimensional accuracy. The feature of this method is that it can be obtained in a short time.However,
If the preform is heated for a long period of time at a temperature of 150° C. or more before shaping, a thermosetting reaction will proceed and the preform will harden, so it is desirable to shorten the time difference between heating and shaping as much as possible.

Example 1 20 parts by weight of methacrylic acid, 80 parts by weight of β-methylglycidyl methacrylate, azobisin butyronitrile a,
A superimposed stock solution consisting of 15 parts by weight of n-octyl mercaptan and 15 parts by weight of n-octyl mercaptan was placed between two tempered glass plates (made of a vinyl chloride tube with an outer diameter of 5 mm) and a thiamine film with a thickness of 50 μm was pasted on the surface. A transparent thermosetting preform with a thickness of 4 mm was created by pouring the frame into an awkwardly shaped space and immersing it in a constant temperature water bath at 70°C for 14 hours.Secondary transformation of this preform To measure the temperature dispersion at a frequency of 110 Hz using a dynamic viscoelasticity measurement device manufactured by Toyo Baldwin Co., Ltd., the peak of the complex modulus (E#) was determined. The following temperature was observed at 85°C. The monomer remaining in the preform was dissolved in chloroform and determined by gas chromatogram to be 10% by weight.

The Tsujiko molded body obtained in this example was then cut into 30 pieces, sandwiched between flat molds heated to 200°C, and immediately left under pressure at a pressure of 70°C/α2 for 10 minutes. Thereafter, it was cooled and peeled off from the mold to obtain a heat-cured sheet with a thickness of about 200 μm. The dynamic viscoelastic properties of this sheet were examined under the same conditions as the preform, and the peak temperature was found to be 180°C.

When this sheet was immersed in acetone and methylene chloride solvent for one day at room temperature and the surface condition was observed, no change was observed in the surface condition, and it had extremely immediate chemical resistance. It turned out that there was. In addition, we measured the total transmittance of visible light using a spectrophotometer and found that it was 400 ntn to 80 ntn.
It showed a transmittance of 90% or more between 0 nm and a light transmittance equivalent to that of polymethyl methacrylate. ◎ Example 2 20 parts by weight of methacrylic acid, 40 parts by weight of β-methylglycidyl methacrylate, 40 parts by weight of methyl methacrylate A polymerization stock solution consisting of 105 parts by weight of azobisisobutyronitrile and 15 parts by weight of n-octylmercaptan CL was polymerized under the same conditions as in Example 1 to create transparent thermosetting preforms with 4 thicknesses. friend.

When the peak temperature and the amount of residual monomer were measured under the same conditions as in Example 1, they were 90°C and 9.0%, respectively. This preform was press-molded as described in Example 1 under the same conditions as the sheet to obtain a heat-cured sheet having a thickness of about 190 .mu.m. The dynamic viscoelastic properties of this sheet were investigated under the same conditions as the preform, and the peak temperature was 178°C. This notebook was immersed in a solvent of acetone and methylene chloride for one day at room temperature, and the surface condition was thoroughly observed. No change was observed in the appearance, indicating excellent chemical resistance. The visible light transmittance was measured at 400 nm using a spectrometer.
It showed a transmittance of 90% or more between ~800 nm and had the same translucency as polymethyl methacrylate ◎Example 3 15 parts by weight of itaconic acid, 40 parts by weight of β-methylglycidyl acrylate, 45 parts by weight of methyl methacrylate A polymerization stock solution consisting of 1 part by weight, 1 part by weight of azobisisobutyronitrile, and 15 parts by weight of n-octyl mercaptan Q was polymerized under the same conditions as in Example 1 to obtain a transparent thermosetting preform with a thickness of 4 mm. 90 Under the same conditions as Example 1, ■I
When I measured the peak temperature and the amount of residual monomer, it was found that
, 60c, 1 (10% by weight) 7t, ko (D) The preformed body described in Example 1 was pressure-molded under the same conditions as the friend's, and a heat-cured sheet with a thickness of about 160 μm was obtained. When the dynamic viscoelastic properties of this sheet were investigated, the p2/I peak temperature was 160°C.The sheet was immersed in a solvent of gold acetone and methylene chloride for one day at room temperature, and the surface condition was observed. However, there is no visible change in appearance, and it exhibits excellent chemical resistance.Visible light transmittance was measured using a t0 minute element meter, and the transmittance of gold was 90% or more between 400 nm and 800 nm. Comparative Example 1 3 parts by weight of methacrylic acid, 47 parts by weight of β-methylglycidyl methacrylate, 50 parts by weight of methyl methacrylate,
A polymerization stock solution consisting of 057 L parts of "Azobisisobutyronitrile" and 15 parts by weight of n-octyl mercaptan Q was polymerized under the same polymerization conditions as in Example 1 to prepare a transparent preform with a thickness of 4 fi. The peak temperature and residual monomer content were measured in the same manner as in Example 1 and found to be 87°C and 10% by weight. Press-formed to a thickness of about 150μ
Get it. The E peak temperature of this sort is 110℃. When this sort was immersed in a solvent of acetone and methylene chloride at room temperature for one day, it swelled and cracked.

Comparative Example 2 20 parts by weight of methacrylic acid, 3 it parts of β-methylglycidyl methacrylate, 77 parts by weight of methyl methacrylate,
A polymerization stock solution consisting of 105 parts by weight of azobisisobutyronitrile and 15 parts by weight of n-octyl mercaptan a was polymerized under the same polymerization conditions as in Example 1 to create a transparent preform with a thickness of 4 mm.几. The E' peak temperature and the amount of residual monomer were measured in the same manner as in Example 1, and the fi
A 7-tone product with a thickness of approximately 140 μm was obtained by pressure molding at 100° C. and under the same conditions as those described in Example 1. 1 of this sheet! The Xl peak temperature was 115°C. When this /-t was immersed in a solvent of acetone and methylene chloride at room temperature for one day, it swelled and cracked.

Comparative Example 3 A transparent preform was prepared under the same conditions as in Example 1 except that the content of n-octyl mercaptan and the polymerization time were 3 (L5 parts by weight and 2 hours). This resin plate was It was soft and difficult to remove from the polymerization cell.

When the amount of residual monomer was examined, it was found to be 35 mm by weight and fco was n'fcl! (Layered plates are soft and sticky, so they are difficult to handle and are a material that poses practical problems for pressure molding.Comparative Example 4 A resin plate similar to Example 1 was molded at a mold temperature of ℃ under the same conditions as in Example 1 to obtain a resin plate with a thickness of 1 inch.The E peak temperature of this resin plate was 110℃. 1 at room temperature in a solvent
After being soaked for a day, it swelled and cracked.
A polymerization stock solution consisting of parts by weight was polymerized under the same conditions as in Example 1 except that the temperature of the constant temperature bath was 120°C, and a transparent thermosetting preform with a thickness of 4 mm was produced. l:a E〃Beak temperature was measured under the same conditions as in Example 1. 14
Hot light at 0℃. This sorting was insoluble in the solvent, making it impossible to measure the amount of residual monomer. All nine trials of pressure molding were carried out under the same conditions as in Example 1, but no deformation occurred and the bottom shape was impossible.

Comparative Example 6 A polymerization stock solution consisting of 3 parts by weight of methacrylic acid, 3 parts by weight of β-methylglycidyl methacrylate, 94 parts by weight of methyl methacrylate, azobisisobutyronitrile Q, 1 part by weight of OS, and 0.15 parts by weight of n-octyl mercaptan. All the same provisions as in Example 1.

Polymerization was performed to create a transparent thermosetting preform of Yusa 41. Under the same conditions as Example 1, E〃heat temperature,
The remaining monomer amount was measured and fixed at 91-℃ and &
It was a double fight. This preformed body was pressure molded under the same conditions as those described in Example 1 and had a thickness of about 130μ.
Get the money. The E' peak temperature for this sort was 112°C. When this sheet metal was immersed in a solvent of acetone and methylene chloride at room temperature for one day, it swelled and cracked.

〔Effect of the invention〕

The preform of the present invention is a transparent thermosetting resin that is a thermoplastic resin in a glass state at room temperature, and has a molecular design that allows the thermosetting reaction to proceed in the molding temperature range of 150°C or higher. . Therefore, it can be handled in the same way as general thermoplastic resins at room temperature, and the bottom shape processing method can also be used under pressure.
Some methods used for thermoplastic resins, such as compression molding, can be applied, and are relatively easy to mass-produce.

Furthermore, the molded product finally obtained from the preformed product of the present invention is thermoset, and has excellent heat resistance, chemical resistance, and dimensional stability, and is superior to conventional thermoplastic and thermoset products. It combines the advantages of both plastics.

Claims (1)

[Claims] At least one carboxyl group-containing vinyl monomer 4-
30% by weight, 4-96% by weight of at least one glycidyl group-containing vinyl monomer and 0-96% of other copolymerizable monomers.
The preform is composed of 92% by weight, the unreacted monomer remaining in the mold is less than 20% by weight, and the secondary transition point of the mold is 120°C or lower. A transparent thermosetting preform characterized by: