JPH1045809A - Methacrylic resin cast polymer - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To submit a methacrylic resin cast polymer having excellent solvent resistance. SOLUTION: Methyl methacrylate 60 to 100% by weight
And 100 parts by weight of a resin component comprising 40 to 0% by weight of another copolymerizable vinyl monomer, and 0.001 of salicylic acid.
~ 0.03 parts by weight and sodium salicylate 0.00
A methacrylic resin cast polymer product produced from 1 to 0.03 parts by weight.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a methacrylic resin cast polymer having excellent solvent resistance obtained by subjecting a monomer mainly composed of methyl methacrylate or a mixture of the monomer and a partial polymer thereof to template polymerization. About.

[0002]

2. Description of the Related Art There are two methods for producing a methacrylic resin sheet, such as a mold-making method and an extrusion-making method. Compared with an extruded plate obtained by melt-molding a resin, a monomer mainly composed of methyl methacrylate is subjected to mold polymerization. The methacrylic resin cast obtained by this method has low optical distortion and a wide selection range of molecular weight, so chemical resistance,
Because workability, mechanical strength, etc. can be increased,
Used in many fields. However, methacrylic resin plates are rarely whitened when a solvent comes into contact with the resin plate during solvent bonding or the like, and it has been a problem, and improvement of this point has been desired.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a methacrylic resin cast product having excellent solvent resistance so that the cast product surface does not whiten when the methacrylic resin cast product comes into contact with a solvent. To provide.

[0004]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned object, and as a result, have added salicylic acid and sodium salicylate to a methyl methacrylate monomer or a mixture thereof with a polymer thereof. As a result, it has been found that a methacrylic resin cast polymer having excellent solvent resistance can be obtained while maintaining the excellent transparency characteristic of the methacrylic resin.

That is, the present invention relates to methyl methacrylate 6
100 parts by weight of a resin component comprising 0 to 100% by weight and 40 to 0% by weight of another copolymerizable vinyl monomer, 0.001 to 0.03 parts by weight of salicylic acid and 0.001 to 0.03% by weight of sodium salicylate And a methacrylic resin cast polymer product produced from

[0006] Further, the present invention relates to methyl methacrylate 60.
To 100% by weight and another copolymerizable vinyl monomer 4
100 parts by weight of a resin component comprising 0 to 0% by weight, 0.001 to 0.03 parts by weight of salicylic acid, 0.001 to 0.03 parts by weight of sodium salicylate, and 0.01 to 0.1 parts by weight of triphenylphosphine. And a methacrylic resin cast polymer product characterized by being produced from:

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the monomer constituting the resin component is not only a methyl methacrylate monomer alone but also a monomer mixture of another vinyl monomer copolymerizable with methyl methacrylate. .

The vinyl monomers copolymerized with methyl methacrylate include, for example, ethyl methacrylate, isopropyl methacrylate, t-butyl methacrylate, s-butyl methacrylate, n-butyl methacrylate, amyl methacrylate, octyl methacrylate 2-ethylhexyl methacrylate, lauryl methacrylate, phenyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, and other cycloalkyl groups; methacrylic esters having 1 to 12 carbon atoms in the alkyl group containing a benzyl group; bornyl methacrylate; Meta having an alkyl group having 8 to 20 carbon atoms or an alicyclic hydrocarbon group, such as isobornyl methacrylate, fentyl methacrylate, 1-methynthyl methacrylate, adantyl methacrylate, and dimethyl adamantel methacrylate. Acrylic acid esters; methyl acrylate, ethyl acrylate, isopropyl acrylate, butyl acrylate, butyl t- acrylate, amyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, cyclohexyl acrylate,
Acrylic esters such as phenyl acrylate and benzyl acrylate; vinyl aromatics such as styrene, α-methylstyrene, paramethylstyrene, isopropenyl styrene, and vinyl toluene; unsaturated nitriles such as acrylonitrile and methacrylonitrile; Unsaturated carboxylic acids such as methacrylic acid, acrylic acid, and maleic anhydride; and polyunsaturated compounds such as ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, and divinylbenzene. However, the present invention is not limited to these, and these can be used alone or in combination of two or more.

The composition ratio of the monomer used for the resin component constituting the methacrylic resin cast polymer of the present invention is usually 60 to 100% by weight of methyl methacrylate and 40 to 100% of another copolymerizable vinyl monomer. Depending on the purpose of improvement, the amount of the other copolymerizable vinyl monomer is reduced to 5% by weight or less so as not to impair the intrinsic physical properties of the methacrylic resin obtained by polymerization. It is desirable to do.

In the present invention, the above-mentioned monomer or monomer mixture (hereinafter, these are simply referred to as “monomer”).
Is subjected to template polymerization, but a mixture of a monomer and its polymer (hereinafter, referred to as “syrup”) may be subjected to polymerization instead of the monomer.

The methacrylic resin of the present invention is characterized in that salicylic acid and sodium salicylate are contained in the above resin components. Among these, sodium salicylate enhances the solvent resistance of the surface of the resin cast polymer. However, although the addition of sodium salicylate provides solvent resistance on the surface of the resin-cast product, it loses transparency and causes water absorption and whitening upon immersion in hot water. Therefore, salicylic acid is used as a compatibilizer.

The amount of sodium salicylate used is 0.001 to 100 parts by weight of the monomer or syrup.
Preferably, it is used in the range of 0.03 parts by weight. If the amount used is less than 0.001 part by weight, the solvent resistance of the surface of the resin cast product is not sufficient, and if the amount used exceeds 0.03 part by weight, the transparency of the obtained resin cast product decreases, Water absorption whitening when immersed in hot water becomes severe. For the addition of sodium salicylate to the resin component, water is used as a solvent in an amount of 1 to 20 times the amount of addition.

The amount of salicylic acid used is preferably in the range of 0.001 to 0.03 parts by weight per 100 parts by weight of monomer or syrup. If the amount used is less than 0.001 part by weight, the transparency of the obtained resin cast product is reduced, and the resin cast product is whitened by water absorption when immersed in hot water. On the other hand, if the amount exceeds 0.03 parts by weight, the strength of the resin cast product obtained will be reduced.

In the present invention, when an organic peroxide-based initiator is used as the polymerization initiator, triphenylphosphine (hereinafter referred to as TPP) which further enhances the solvent resistance of the surface of the resin-cast product.
Abbreviated. ) Is preferably used in combination. The amount of TPP used is preferably in the range of 0.01 to 0.1 part by weight per 100 parts by weight of the monomer or syrup,
If the amount used is less than 0.01 part by weight, the solvent resistance of the surface of the resin cast product is not sufficient, and if the amount used exceeds 0.1 part by weight, the obtained resin cast product is colored or the strength is reduced. Will bring.

The cast methacrylic resin product of the present invention is polymerized by a template polymerization method.

The polymerization initiator which can be used for the polymerization of the monomer or syrup in the template polymerization includes azobisisobutyronitrile, 2,2'-azobis- (2,4
-Dimethylvaleronitrile), and organic peroxides such as benzoyl peroxide, t-butylperoxy 2-ethylhexanoate, and t-hexylperoxypivalate.

In the polymerization, a molecular weight regulator is used as required. This includes n-butyl mercaptan, n
-Alkyl mercaptans such as dodecyl mercaptan and octyl mercaptan.

The polymerization temperature varies depending on the type of polymerization initiator used, but is generally from 40 to 170 ° C., the first stage being 40 to 90 ° C. and the second being 100 to 140 ° C.
It is preferred to carry out the polymerization at the step polymerization temperature.

In the polymerization, various additives used in producing ordinary methacrylic resins or modified products thereof can be added. Additives include dyes, pigments or antioxidants used for coloring, stabilizers such as ultraviolet absorbers or flame retardants, plasticizers or release agents that facilitate the release of resin castings from molds, chain transfer agents And a crosslinking agent.

[0020]

The present invention will be described below in detail with reference to examples. In the description, “parts” means parts by weight. In addition, the physical property evaluation in an Example was performed based on the following method. (1) Transparency The transparency and coloring of the resin-cast product were observed under illumination in a dark place. A good product was evaluated as ○, a slightly good product was evaluated as Δ, and a poor product was evaluated as ×. (2) Hot water resistance The resin cast was immersed in warm water at 80 ° C. for 24 hours, and the degree of whitening was evaluated as “No whitening”, “Slightly white”: Δ, and “Whitening”. (3) Solvent resistance No whitening depending on the degree of whitening on the surface of the resin casting when the resin casting is exposed to methylene chloride vapor: ○, slightly whitening:
Δ, whitening: evaluated as x.

[Examples 1 to 3] Methyl methacrylate was supplied to a reactor equipped with a cooling pipe, a thermometer and a stirrer.
2'-azobis- (2,4-dimethylvaleronitrile)
After adding 0.05 part, the mixture was heated until the internal temperature reached 90 ° C., and the temperature was maintained for 8 minutes, and then cooled to room temperature to obtain a syrup having a polymerization rate of about 22% and a viscosity of 1500 centipoise at 20 ° C. .

Then, 0.083 part of 2,2'-azobis- (2,4-dimethylvaleronitrile) as a polymerization initiator, salicylic acid in the amount shown in Table 1 and 1000 ppm of pure water were added to 100 parts of the syrup. After adding sodium salicylate as a solvent, the mixture was stirred, and two SUs opposed to each other at a distance of 3 mm via a polyvinyl chloride gasket.
It was poured into a mold formed of an S304 plate, immersed in hot water at 78 ° C. for 30 minutes to polymerize and cure, and then heat-treated in an air heating furnace at 135 ° C. for 60 minutes. After cooling, the mold was deframed to obtain a resin casting having a thickness of about 3 mm. The physical properties of this resin casting were evaluated. The results are shown in Table 1.

[Comparative Examples 1 to 5] 2,2'-Azobis- (2,4-dimethylvaleronitrile) was added as a polymerization initiator to 100 parts of the same syrup as used in Examples 1 to 3. 0.083 parts of salicylic acid in the amount shown in Table 1 and sodium salicylate using 0.1 part of pure water as a solvent were added, and the same procedure as in Example 1 was carried out to obtain a resin cast product, and the physical properties were evaluated. . The results are shown in Table 1.

As is clear from Table 1, Examples 1 to 3, which are resin cast products of the present invention, suppress whitening after immersion in hot water and whitening on the surface of the cast product after exposure to solvent vapor while maintaining transparency. On the other hand, in the case of a resin casting product to which salicylic acid and sodium salicylate were not added (Comparative Example 1), the surface of the casting product was whitened after exposure to solvent vapor. In addition, the cast resin products (Comparative Examples 2 and 3) out of the preferred usage range have whitened surfaces or lost transparency after exposure to solvent vapor.
The cast resin product to which sodium salicylate alone was added (Comparative Example 4) lost transparency, and the cast resin product to which salicylic acid alone was added (Comparative Example 5) became white after cast solvent vapor exposure. ing.

[Examples 4 to 6] Into the same apparatus as in Example 1, 95.7 parts by weight of methyl methacrylate and 4.3 parts by weight of butyl acrylate were fed, and n-dodecylmercaptan was used as a molecular weight regulator in an amount of 0%. After the addition of 0.063 parts, the mixture was heated with stirring and when the internal temperature reached 80 ° C., 2,2′-azobis- (2,4-dimethylvaleronitrile) 0.05 was added.
The mixture was further heated until the internal temperature reached 90 ° C., and the temperature was maintained for 13 minutes.
A 6% syrup having a viscosity of 2000 centipoise at 20 ° C. was obtained.

Next, 0.03 part of n-dodecyl mercaptan as a molecular weight regulator was added to 100 parts of this syrup,
0.32 parts of t-hexyl peroxypivalate as an organic peroxide-based polymerization initiator, the amount of TPP shown in Table 1,
Sodium salicylate using salicylic acid and 0.1 part of pure water as a solvent was added, and the same procedure as in Example 1 was carried out to obtain a resin cast product, and the physical properties were evaluated. The results are shown in Table 1.

[Comparative Examples 6 and 7] 100 parts of a syrup similar to that obtained in Example 4 was added with n-type as a molecular weight regulator.
0.03 parts of dodecyl mercaptan, 0.32 parts of t-hexyl peroxypivalate as an organic peroxide-based polymerization initiator, and the amounts of TPP, sodium salicylate and 0.1 parts of pure water shown in Table 1 in a solvent were used. , And the same procedure as in Example 4 was carried out to obtain a resin cast product, and the physical properties were evaluated. Table 1 shows the results.
It was shown to.

As is evident from Table 1, Examples 4 to 6, which are resin cast products of the present invention, maintain whiteness after immersion in hot water and whitening of the cast product surface after exposure to solvent vapor while maintaining transparency. On the other hand, the resin castings (Comparative Examples 6 and 7), which are out of the preferred range, have whitened surfaces or lost transparent products after exposure to solvent vapor.

[Examples 7 and 8] Methyl methacrylate was supplied to the same apparatus as in Example 1, heated while stirring, and when the internal temperature reached 75 ° C, azobisisobutyronitrile 0.002 was added. And further heated to an internal temperature of 95 ° C.
After holding for 0 minutes, the mixture was cooled to room temperature and the polymerization rate was about 8%.
A syrup having a viscosity of 200 centipoise at ° C was obtained.

Next, 100 parts of this syrup was charged with 0.003 parts of 2,2'-azobis- (2,4-dimethylvaleronitrile) as a polymerization initiator, salicylic acid in the amount shown in Table 1 and 0.1% of pure water. After adding sodium salicylate using a solvent as a solvent, the mixture was stirred and poured into a mold formed of two opposing inorganic glass plates at an interval of 10 mm via a polyvinyl chloride gasket, and then poured into hot water at 65 ° C. After immersion for 6 hours for polymerization and curing, heat treatment was performed in an air heating furnace at 125 ° C. for 3 hours. After cooling, the mold is unframed and the plate thickness is about 10 mm
Was obtained. The properties of the resin cast were evaluated and are shown in Table 1.

Comparative Examples 8 to 9 To 100 parts of a syrup similar to that obtained in Example 7, salicylic acid in an amount shown in Table 1 and sodium salicylate using 0.1 part of pure water as a solvent were added. Thereafter, in the same manner as in Example 7, a resin cast product was obtained, and the physical properties were evaluated. The results are shown in Table 1.

As is clear from Table 1, Examples 7 and 8, which are resin cast products of the present invention, maintain whiteness after immersion in hot water and whitening of the surface of cast products after exposure to solvent vapor while maintaining transparency. On the other hand, the resin castings (Comparative Examples 8 and 9), which are out of the preferred range of use, have whitened surfaces or lost transparency after exposure to solvent vapor.

[0033]

[Table 1]

[0034]

The methacrylic resin cast polymer product of the present invention is
The whitening of the resin surface that occurs when the resin is exposed to a solvent vapor can be prevented while maintaining the excellent transparency characteristic of the methacrylic resin.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Junichiro Shin 20-1 Miyuki-cho, Otake City, Hiroshima Prefecture Mitsubishi Rayon Co., Ltd. Central Research Laboratory (72) Inventor Yoshinori Fukuba 20-1 Miyuki-cho, Otake City, Hiroshima Prefecture No. Mitsubishi Rayon Co., Ltd. Central Research Laboratory (72) Koji Shiga 20-1 Miyuki-cho, Otake City, Hiroshima Prefecture Mitsubishi Rayon Co., Ltd. Central Research Laboratory (72) Inventor Jun Nakauchi Miyuki-cho, Otake City, Hiroshima Prefecture No. 20 No. 1 in the Mitsubishi Rayon Co., Ltd. Otake Office

Claims (2)

[Claims] 1. Methyl methacrylate 60 to 100% by weight
And 100 parts by weight of a resin component comprising 40 to 0% by weight of another copolymerizable vinyl monomer, and 0.001 of salicylic acid.
~ 0.03 parts by weight and sodium salicylate 0.00
A methacrylic resin cast polymer product produced from 1 to 0.03 parts by weight. 2. 60 to 100% by weight of methyl methacrylate
And 100 parts by weight of a resin component comprising 40 to 0% by weight of another copolymerizable vinyl monomer, and 0.001 of salicylic acid.
0.03 parts by weight, sodium salicylate 0.001
0.03 parts by weight and triphenylphosphine 0.0
A methacrylic resin cast polymer product produced from 1 to 0.1 part by weight.