JPH10237132A - Methacrylic resin material and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a methacrylic resin material excellent in thermoforming and processing properties, capable of being smoothly carried out deep draw and bending with high dimensional accuracy, excellent in hot water resistance and resistance to moist heat, and not causing haze, whitening, crack, blister, etc., even if exposed to hot water or heated steam for a long period, and effectively usable for various kinds of uses including sanitary field such as bathtub, washroom or toilet. SOLUTION: This methacrylic resin material has a structural unit (a) derived from methyl methacrylate, (meth)acrylic acid alkyl ester structural unit (b) other than methyl methacrylate and a structural unit (c) derived from α- methylstyrene dimer and has (80:20) to (99:1) weight ratio of the unit (a) to the unit (b) and 100: (0.05-2) ratio of total weight of the structural unit (a) and the structural unit (b)} to structural unit (c)}.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a methacrylic resin material, a method for producing the same, and a molded article made of the methacrylic resin material. More specifically, the present invention is excellent in thermoforming workability, can perform deep drawing or bending under heating with high dimensional accuracy smoothly, and is excellent in hot water resistance and wet heat resistance. Even when exposed to hot water or heated steam for a long period of time, haze, whitening, cracks, methacrylic resin material that does not generate blisters, a method for producing the same, and a molded article comprising the methacrylic resin material, The thermoplastic resin material of the present invention takes advantage of the above-mentioned excellent properties, and is effectively used for bathrooms, bathtubs, washrooms, sanitary fields such as toilets, kitchen products, interior and exterior materials of houses, and various other uses. Can be used.

[0002]

2. Description of the Related Art Methacrylic resins are excellent in transparency, colorability, moldability, weather resistance, etc., and are utilized in various applications as signboards, decorative materials, lighting covers, automobile parts, glazing materials, etc. Widely used in the field. Furthermore, in recent years, with the expanding use of methacrylic resins,
It is also used in so-called sanitary fields such as bathtubs, bathrooms, washrooms, and kitchen fields such as top plates of system kitchens. Unsaturated polyesters have hitherto been widely used as plastic tubs, but have a problem such as deterioration of the surface when used for a long time due to poor hydrolysis resistance. On the other hand, a bath made of a methacrylic resin is excellent in hydrolysis resistance and has no problem such as deterioration due to hot water as in an unsaturated polyester resin, but has insufficient thermoforming workability.

[0003] Molded articles used in sanitary fields such as bathtubs and wash basins, kitchens, and the like, unlike signboards, which are often formed of flat surfaces, have many curved portions, and therefore, methacrylic used in those applications. For the base resin, high thermoforming workability that can perform drawing and bending with high dimensional accuracy is required.
Conventionally, development of a methacrylic resin material having improved moldability has been attempted.

[0004] As such a prior art, a methacrylate methacrylate syrup containing a methyl methacrylate polymer is polymerized by adding a chain transfer agent comprising mercaptan, polyhaloalkane or phosphine and a cross-linking agent. Method for manufacturing sheet (Japanese Patent Laid-Open No. 54-142)
No. 270), alkyl mercaptan, aromatic mercaptan, thioglycolic acid, thioglycolic acid ester, and a monomer mixture mainly composed of methyl methacrylate.
A chain transfer agent consisting of β-mercaptopropionic acid or β-mercaptopropionate and a polymerization initiator are added and polymerized to form a syrup, and a polymerization initiator and a crosslinking agent are added to the syrup and polymerized in a mold. Method for manufacturing acrylic resin sheet (Japanese Patent Publication No. 6-70098)
Is known. However, although the methacrylic resin materials obtained by those conventional techniques show some improvement in thermoforming workability, hot water resistance, wet heat resistance are not sufficient, and when exposed to hot water or high-temperature steam. , Haze, whitening, cracks, etc.
It cannot be used in sanitary fields such as bathtubs, bathrooms, vanities, and tops in system kitchens.

Also, methyl methacrylate, styrene, α
Polymerizing a monomer mixture comprising 70% by weight or more and less than 95% by weight of a monomer such as methylstyrene, 5% by weight or more and 30% by weight of a crosslinking agent such as ethylene glycol dimethacrylate, and 0.1 to 2% by weight of α-methylstyrene dimer; Transparent plastics are known (Japanese Patent Laid-Open No. 58-1983)
-201812). However, in this prior art, the crosslinking agent is used in an extremely large amount of 5 to 30% by weight, so that the plastic obtained therefrom is a thermosetting resin which does not deform or fuse by heat. When a product having a curved portion or the like is obtained from, mechanical processing such as cutting or polishing is used. For this reason, draw-forming and bending under heating cannot be performed on this plastic.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to produce a product having a curved portion with excellent dimensional accuracy, which is excellent in thermoforming processability and which is subjected to drawing or bending under heating. It is an object of the present invention to provide a methacrylic resin material which is excellent in hot water resistance and moist heat resistance and does not cause troubles such as haze, whitening, cracks, and blisters even when exposed to hot water or heated steam for a long time. . An object of the present invention is to provide a method for producing a methacrylic resin material having the above-described excellent characteristics. Another object of the present invention is to provide a molded article made of a methacrylic resin material having the above-mentioned excellent characteristics.

[0007]

The present inventors have made various studies in order to achieve the above object. As a result, a specific amount of the alkyl (meth) acrylate component other than methyl methacrylate is blended with the methyl methacrylate component, and α-methylstyrene dimer is particularly selected as a chain transfer agent, and the specific When a methacrylic resin material is manufactured using the polymerizable mixture containing the methacrylic resin material, the resulting methacrylic resin material has excellent thermoforming properties, and is subjected to drawing and bending under heating to form a curved portion. It can be manufactured with high dimensional accuracy and has excellent hot water resistance and moist heat resistance, and does not cause problems such as haze, whitening, cracks, and blisters even when exposed to hot water or heated steam for a long period of time. Was found. Further, the present inventors have found that when (meth) acrylic acid polyhydric ester is used in a specific amount or less during the production of such a methacrylic resin material, the heat resistance is improved in addition to the above-mentioned properties, and the thickness is uneven. They have found that a methacrylic resin material having an effect of prevention can be obtained, and completed the present invention based on those findings.

That is, the present invention relates to (i) a structural unit (a) derived from methyl methacrylate, an alkyl methacrylate having an alkyl group having 2 to 20 carbon atoms, and an alkyl group having 1 to 20 carbon atoms. A structural unit (b) derived from at least one alkyl (meth) acrylate selected from a certain alkyl acrylate, and a structural unit (c) derived from an α-methylstyrene dimer which may have a substituted benzene nucleus (Ii) a weight ratio of the structural unit (a) to the structural unit (b) is from 80:20 to 99: 1;
And (iii) {the total weight of the structural unit (a) and the structural unit (b)}: {the weight of the structural unit (c)} is 100:
Methacrylic resin material characterized by being 0.05 to 2.

Further, the present invention relates to a method for preparing a copolymer comprising the structural unit (d) derived from the polyhydric ester of (meth) acrylic acid in an amount of 5% by weight based on the total weight of the structural unit (a) and the structural unit (b). The methacrylic resin material further has the following ratio.

The present invention relates to (i) (a) methyl methacrylate, (b) an alkyl methacrylate having an alkyl group having 2 to 20 carbon atoms, and an acryl having an alkyl group having 1 to 20 carbon atoms. A polymerizable mixture containing at least one alkyl (meth) acrylate selected from acid alkyl esters, and (c) an α-methylstyrene dimer in which a benzene nucleus may be substituted;
Or methyl methacrylate and / or (meth)
The polymerizable mixture containing a polymer comprising an alkyl acrylate (b), wherein (ii) a methyl methacrylate component: the alkyl (meth) acrylate [hereinafter referred to as “alkyl (meth) acrylate (b) ) "
Weight ratio of the components is from 80:20 to 99:
1, and the ratio of (iii) {the total weight of the methyl methacrylate component and the alkyl (meth) acrylate (b) component}: {the weight of the α-methylstyrene dimer component} is 100: 0.05 to 2. A method for producing a methacrylic resin material, comprising polymerizing the polymerizable mixture of No. 2 using a polymerization initiator.

[0011] The present invention also relates to the present invention, wherein the (d) (meth) acrylic acid polyester component is 5% by weight or less based on the total weight of the methyl methacrylate component and the (meth) acrylic acid alkyl ester (b) component. A method for producing a methacrylic resin material, characterized by polymerizing the above-mentioned polymerizable mixture further containing the above-described polymerizable mixture using a polymerization initiator. Further, the present invention is a sanitary molded article made of the methacrylic resin material described above.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. As described above, the methacrylic resin material of the present invention has a structural unit (a) derived from methyl methacrylate, an alkyl methacrylate having an alkyl group having 2 to 20 carbon atoms, and an alkyl group having 1 to 2 carbon atoms. At least one selected from alkyl acrylates which is 20
Alkyl (meth) acrylates [ie, alkyl groups other than methyl methacrylate have 1 to 20 carbon atoms
(Meth) acrylic acid alkyl ester], and a methacrylic resin having at least a structural unit (c) derived from α-methylstyrene dimer.

The structural unit (b) is, as described above, a structural unit composed of an alkyl (meth) acrylate other than methyl methacrylate, wherein the alkyl group in the alkyl ester has 1 to 20 carbon atoms. (Meth) acrylic acid alkyl ester [hereinafter referred to as “(meth) acrylic acid alkyl ester (b)”],
It is preferable that the alkyl group is composed of an alkyl (meth) acrylate (b) having 1 to 12 carbon atoms. Examples of the alkyl (meth) acrylate (b) include methyl acrylate, ethyl acrylate, propyl acrylate, isobutyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, ethyl methacrylate, propyl methacrylate, and methacryl. Examples thereof include propyl acrylate, isobutyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, and lauryl methacrylate. The methacrylic resin material is
It may have a structural unit derived from one or more of the above-mentioned alkyl (meth) acrylates (b). Among them, the structural unit (b) may be a structural unit derived from at least one of 2-ethylhexyl acrylate, butyl acrylate, and lauryl methacrylate, and may have thermoforming workability, hot water resistance, wet heat resistance, and the like. It is more preferable from the viewpoint.

The α-methylstyrene dimer constituting the structural unit (c) in the methacrylic resin material of the present invention is represented by the following chemical formulas (I) and (II);

[0015]

Embedded image Or a substituent in which one or both of the two benzene nuclei do not significantly affect the chain transfer effect (for example, an alkyl group having 1 to 4 carbon atoms, preferably methyl A structural unit derived from at least one of substituted α-methylstyrene dimers substituted with a group, an ethyl group, or the like.

The methacrylic resin material of the present invention may be composed of one type of methyl methacrylate-based polymer or a blend of two or more types of methyl methacrylate-based polymers. When viewed from the resin material as a whole, the structural units (a), (b) and (c) are present in some form as units bonded in the methacrylic resin at the ratio described below. And a methacrylic resin material may be formed.

In the methacrylic resin material of the present invention, the weight ratio of the structural unit (a): structural unit (b) is 80:20 to 99:
It is necessary to be 1, and it is preferably 90:10 to 99: 1, and more preferably 92: 8 to 98.5: 1.5. Structural unit (a) and structural unit (b)
If the ratio of the structural unit (a) is less than 80% by weight based on the total weight of
Is exceeded, the glass transition temperature becomes too low, and physical properties such as thermal properties and mechanical strength are reduced. On the other hand, based on the total weight of the structural unit (a) and the structural unit (b), if the ratio of the structural unit (a) exceeds 99% by weight, [the ratio of the structural unit (b) is less than 1% by weight. ], The moldability deteriorates, and the desired methacrylic resin material cannot be obtained.

Further, in the methacrylic resin material of the present invention, {the total weight of the structural unit (a) and the structural unit (b)}: {the weight of the structural unit (c)} when viewed from the entire methacrylic resin material. Is required to be 100: 0.05 to 2, preferably 100: 0.1 to 1, and more preferably 100: 0.2 to 0.8. If the proportion of the structural unit (c) derived from α-methylstyrene dimer is less than 0.05 part by weight based on 100 parts by weight of the total of the structural unit (a) and the structural unit (b), the methacrylic resin material Does not exhibit the effect of reducing the degree of polymerization due to α-methylstyrene dimer, making it impossible to obtain a methacrylic resin material having excellent thermoformability. On the other hand, when the ratio of the structural unit (c) derived from α-methylstyrene dimer exceeds 2 parts by weight based on 100 parts by weight of the total of the structural unit (a) and the structural unit (b), the α-methylstyrene dimer Polymerization inhibition by too large,
The polymerization reaction for producing the methacrylic resin material does not proceed smoothly.

Further, the methacrylic resin material of the present invention comprises:
If necessary, it may have a structural unit (d) derived from a (meth) acrylic acid polyvalent ester. The (meth) acrylic acid polyvalent ester constituting the structural unit (d) is
It is a polyhydric ester such as di-, tri-, or tetra- (meth) acrylate of polyhydric alcohol such as diol, triol and tetraol. Specific examples of (meth) acrylic acid polyvalent ester include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol tri (meth) acrylate, and polyethylene glycol di (meth) acrylate.
Acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, trimethylolethanedi (meth) acrylate, neopentyl glycol di ( Meth) acrylate, 1,3
-Butylene glycol di (meth) acrylate, 1,4
-Butylene glycol di (meth) acrylate, 1,6
-Hexane glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, 2,2-bis [4- (methacryloxyethoxy) phenyl] propane, 2,2-bis [methacrylic [Roxydiethoxy) phenyl] propane. The methacrylic resin material of the present invention may have a structural unit derived from one or more of the above-mentioned (meth) acrylic polyvalent esters.

When the methacrylic resin material has a structural unit (d) derived from a (meth) acrylic acid polyester, the (meth) acrylic acid polyester functions as a crosslinking agent, and the methacrylic resin material Since a cross-linking bond is formed therein, it is possible to improve heat resistance and prevent uneven thickness in a molded product [hereinafter, (meth) acrylic acid polyester may be referred to as a cross-linking agent]. The content of the structural unit (d) in the methacrylic resin material is calculated based on the structural unit (a)
0 to 5% by weight based on the total weight of the structural unit (b)
And more preferably 2% by weight or less. If the content of the structural unit (d) in the methacrylic resin material is more than 5% by weight, the thermoforming processability is deteriorated, so that deep drawing cannot be performed, bending cannot be performed, and cracking occurs during forming. Is more likely to occur.

In the method for producing the methacrylic resin material of the present invention, the structural unit (a), the structural unit (b), the structural unit (c) and, if necessary, the structural unit (d) are contained in the above-mentioned ratio. Any method can be adopted as long as it can produce a methacrylic resin material, but the following method is preferably employed. That is, the methacrylic resin material of the present invention comprises (i) (a) methyl methacrylate,
(B) alkyl methacrylate having 2 to 20 carbon atoms in the alkyl group and 1 to 2 carbon atoms in the alkyl group;
At least one alkyl (meth) acrylate selected from alkyl acrylates which is 0,
(C) a polymerizable mixture containing an α-methylstyrene dimer whose benzene nucleus may be substituted, and optionally (d) a poly (meth) acrylate, or methyl methacrylate and / or the (meth) acryl The polymerizable mixture containing a polymer comprising the acid alkyl ester (b), wherein the weight ratio of (ii) the methyl methacrylate component: the (meth) acrylic acid alkyl ester (b) component is 80:20 to 99. (Iii) {the total weight of methyl methacrylate and the alkyl (meth) acrylate (b) component}: the ratio of {the weight of the α-methylstyrene dimer component} is 100: 0.05 to 2; And
And (iv) a polymerizable mixture containing a poly (meth) acrylate component in an amount of 0 to 5% by weight based on the total weight of the methyl methacrylate component and the alkyl (meth) acrylate (b) component. Is preferably produced by a method of polymerizing using a polymerization initiator.

More specifically, in the present invention, any one of the following methods (A) to (C) is preferably employed. (A) A polymerizable mixture (monomer mixture) containing methyl methacrylate, alkyl (meth) acrylate (b), α-methylstyrene dimer and optionally (meth) acrylic acid polyester, The weight ratio of methyl acrylate: alkyl (meth) acrylate (b) is 80:20 to 99: 1, and the total weight of methyl methacrylate and alkyl (meth) acrylate (b) is: α- The ratio by weight of the methylstyrene dimer is from 100: 0.05 to 2 and optionally the poly (meth) acrylate is based on the total weight of methyl methacrylate and alkyl (meth) acrylate (b) A polymerizable mixture (monomer mixture) containing the polymerizable mixture at a ratio of 0 to 5% by weight using a polymerization initiator.

(B) Methyl methacrylate is polymerized using a polymerization initiator to produce a syrup containing a methyl methacrylate polymer, and the syrup is provided with (meth) alkyl acrylate (b) and α-methylstyrene dimer. And if necessary, further adding (meth) acrylic acid polyhydric ester and, if necessary, methyl methacrylate, including the amount of the methyl methacrylate component constituting the methyl methacrylate polymer contained in the syrup. The weight ratio of the total methyl methacrylate component: the alkyl (meth) acrylate (b) is 80:20 to 99: 1, and the total of the total methyl methacrylate component and the alkyl (meth) acrylate (b) Weight}: {weight of α-methylstyrene dimer} is 100: 0.05-2, and optionally A polymerizable mixture (methyl methacrylate polymer) containing a poly (meth) acrylate in an amount of 0 to 5% by weight based on the total weight of all methyl methacrylate components and alkyl (meth) acrylate (b) A polymerizable mixture), and polymerizing the polymerizable mixture using a polymerization initiator.

(C) Methyl methacrylate and alkyl (meth) acrylate (b) are polymerized by using a polymerization initiator to obtain a copolymer of methyl methacrylate / alkyl (meth) acrylate (b) and optionally A syrup containing a methyl methacrylate polymer or a (meth) acrylic acid alkyl ester (b) polymer is prepared, and the syrup contains α-methylstyrene dimer and optionally (meth) acrylic acid polyester, and if necessary, Methyl methacrylate and / or alkyl (meth) acrylate (b) is added, and a methyl methacrylate / alkyl (meth) acrylate (b) copolymer contained in the syrup, a methyl methacrylate polymer, Methacryl Constituting Alkyl (meth) acrylate (b) Polymer The amount of methyl and component (meth)
Including the amount of the alkyl acrylate (b) component,
The weight ratio of all methyl methacrylate components to all alkyl (meth) acrylate (b) components is 80:20 to 99:
1, the total weight of all methyl methacrylate components and all alkyl (meth) acrylate (b) components}:
The ratio of {weight of α-methylstyrene dimer} is 100:
0.05 to 2 and optionally 0 to 5% by weight based on the total weight of the total methyl methacrylate component and the total alkyl (meth) acrylate component (b) component. Make a polymerizable mixture containing in proportion (polymerizable mixture containing the above-mentioned polymer),
A method of polymerizing the polymerizable mixture using a polymerization initiator.

The alkyl (meth) acrylate (b), α-methylstyrene dimer and poly (meth) acrylate used together with methyl methacrylate in the method for producing a methacrylic resin material described above include the methacrylic acid of the present invention. As the compounds constituting the structural units (b), (c) and (d) in the system resin material, one or more of the same compounds as described above are used.

As the polymerization initiator used in the above-mentioned method for producing a methacrylic resin material, any polymerization initiator conventionally used for producing a methacrylic resin can be used. A radical polymerization initiator such as an oxide polymerization initiator is preferably used. Although not particularly limited, specific examples of the azo polymerization initiator include 2,2′-azobisisobutyronitrile,
1′-azobis-1-cyclohexanecarbonitrile,
Examples thereof include 2,2'-azobis-2,4-dimethylvaleronitrile and 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile. Also,
Specific examples of the peroxide-based polymerization initiator include t-butylperoxyisobutyrate, 1,1′-bis-t-butylperoxy-3,3,5-trimethylcyclohexane,
Lauroyl peroxide and the like can be mentioned.
The amount of the polymerization initiator to be used is preferably 0.0001 to 2% by weight based on the weight of the polymerizable mixture,
More preferably, it is 0.001 to 1% by weight. The polymerization method for producing the methacrylic resin material is not particularly limited, but a casting method is preferably employed.

The polymerization temperature or the polymerization / molding temperature may vary depending on the polymerization method to be employed, the type of the polymerization / molding method, the composition of the polymerizable mixture used for the polymerization, and the like. It is preferably adopted. For example,
When the casting method is used, the first-stage polymerization is performed at a temperature of 40 to 90 ° C., and then the second-stage polymerization is performed at a temperature of 100 to 140 ° C., and the polymerization and molding are performed at the same time. (Methacrylic resin molded product)
Can be obtained smoothly.

Also, the methacrylic resin material of the present invention comprises:
If necessary, various additives such as dyes and pigments, stabilizers such as antioxidants and ultraviolet absorbers, plasticizers, release agents and the like may be contained. When an additive is contained in the methacrylic resin of the present invention, the additive may be added at any stage before polymerization or polymerization / molding is performed.

The shape, structure, dimensions, and the like of the methacrylic resin material of the present invention are not particularly limited, and can be determined according to the purpose of use and application. In particular, the methacrylic resin material of the present invention is excellent in thermoforming processability, and easily and smoothly bends under heating, and performs a secondary forming process such as deep drawing to form a desired molded product. Can be manufactured with high dimensional accuracy, so that it is convenient to form a plate-like molded product that is easy to use for bending and deep drawing.

The methacrylic resin material of the present invention is excellent in hot water resistance, wet heat resistance and transparency, and causes haze, whitening, cracking, swelling, etc. even when exposed to hot water or heated steam for a long period of time. As it is difficult, it is used as sanitary products such as bathtubs, bathroom wall materials and flooring materials, bathroom vanities, kitchen products such as top plates for system kitchens, as well as doors, bay windows and other interior and exterior materials for houses and the like. Can be effectively used for various applications.

[0031]

EXAMPLES The present invention will be described below in more detail with reference to examples and the like, but the present invention is not limited thereto. In the following examples, parts mean parts by weight unless otherwise specified. Further, various properties shown in the following examples were measured or evaluated as follows.

(I) Hot water resistance (boiling resistance) : Water is placed in a metal container, and the methacrylic resin material obtained in the following Examples or Comparative Examples (plate-like molded product having a thickness of 5 mm) is obtained. ) Is immersed in a test piece having a size of 50 mm × 50 mm cut out from the above.
The test piece was immersed in hot water for 300 hours while maintaining the temperature at 95 ° C., taken out of the hot water after 300 hours, and its haze value was measured with a total light transmittance meter (manufactured by Murakami Color Research Laboratory: HR-100) to determine hot water resistance (boiling resistance).

(Ii) Thermoforming workability : From the methacrylic resin material (plate-like molded product having a thickness of 5 mm) obtained in the following Examples or Comparative Examples, the size was 50%.
A test piece of 0 mm × 700 mm was cut out, and the test piece was heated to 190 ° C. and 200 ° C. by an infrared heater, and vacuum forming was performed at each temperature at −740 mm.
Performing under reduced pressure of Hg (under a pressure of 20 mmHg),
(A molded body for a bathtub model) having the shape and the bent portion dimensions (curvature radius) shown in FIG. FIG.
(A) is a longitudinal sectional view of a molded article obtained by the above-mentioned vacuum forming, and (b) of FIG. 1 is a plan view of the molded article obtained by the above-mentioned vacuum forming when viewed from above. It is. The dimensions (curvature radii) of the portions corresponding to the five bent portions indicated by 1R to 5R in FIG. 1B on the inner surface of the vacuum forming die are 1R = 30 mm, 2R = 30 mm, and 3R = 40.
mm, 4R = 30 mm and 5R = 40 mm. The dimensions (curvature radii) of the five bent portions indicated by 1R to 5R in FIG. 1B of the molded body obtained by the vacuum molding described above were measured, and the values were measured by the vacuum molding die. (Radius of curvature) of the portion corresponding to the 1R to 5R on the inner surface of
Was determined, and the presence or absence of a defective portion such as generation of a crack was examined to evaluate the thermoforming workability. Dimensions (curvature radius) of each bent part of the compact
Is the same as the size (radius of curvature) of each bent portion of the inner surface of the vacuum forming die, it is determined that the thermoforming workability is good. If it is large, it is because the test piece did not adhere to the inner surface of the vacuum forming die during vacuum forming, and thus the thermoforming workability is determined to be poor.

Example 1 (1) To 50 kg of methyl methacrylate, 1 g of 2,2′-azobisisobutyronitrile (polymerization initiator) was added.
After heating to 95 ° C. for 35 minutes with stirring, the mixture was cooled to room temperature to obtain a syrup containing a methyl methacrylate polymer (polymerization rate: 10%). (2) To 10 kg of the syrup obtained in the above (1), 3 kg of methyl methacrylate, 390 g of 2-ethylhexyl acrylate, 1,3-butylene glycol dimethacrylate [(meth) acrylic acid polyester; crosslinking agent] 52
g and α-methylstyrene dimer (chain transfer agent) 5
2 g was added and mixed uniformly, and 13 g of stearic acid (release agent) and an ultraviolet absorber (manufactured by CIBA GEIGY):
2.6 g of Tinuvin P) and 2,2′-azobis-
2,4-dimethylvaleronitrile (polymerization initiator) 2.5
g was added and mixed to prepare a liquid polymerizable mixture. (3) After defoaming the polymerizable mixture obtained in the above (2), a gasket is injected between two parallel tempered glass molds according to a conventional method, and a 70 ° C. water bath is used. For 4 hours, and then heated in an air bath at 120 ° C. for 2 hours to complete the polymerization to produce a methacrylic resin material (plate-like molded product) having a thickness of 5 mm. (4) Using a test piece prepared from the methacrylic resin material (plate-like molded product) obtained in the above (3), the haze value was measured by the method described in the above (i), and the hot water resistance (boiling resistance) was measured. ), A molded article was prepared by the method described in (ii) above, and its thermoforming workability was evaluated. The results are as shown in Table 1 below. Further, during the production of the molded product, there was no occurrence of a defective portion such as a thinned portion or a crack.

Example 2 (1) To 10 kg of a syrup obtained by performing the same operation as in (1) of Example 1, 3 kg of methyl methacrylate, 650 g of 2-ethylhexyl acrylate, ethylene glycol dimethacrylate (crosslinking agent) ) 52 g and 52 g of α-methylstyrene dimer (chain transfer agent) were added and uniformly mixed, and further mixed with a releasing agent, an ultraviolet absorber and a polymerization initiator in the same manner as in (2) of Example 1. Thus, a liquid polymerizable mixture was prepared. (2) Using the polymerizable mixture obtained in the above (1),
A methacrylic resin material (plate-like molded product) having a thickness of 5 mm was manufactured in exactly the same manner as (3) of Example 1. (3) Using a test piece prepared from the methacrylic resin material (plate-like molded product) obtained in the above (2), the haze value was measured by the method described in the above (i), and the hot water resistance (boiling resistance) was measured. ), A molded article was prepared by the method described in (ii) above, and its thermoforming workability was evaluated. The results are as shown in Table 1 below. Further, during the production of the molded body, no defective portion such as a thinned portion or a crack was generated.

Example 3 (1) To 10 kg of a syrup obtained by performing the same operation as (1) of Example 1, 3 kg of methyl methacrylate, 650 g of 2-ethylhexyl acrylate, 1,3-butylene glycol di 26 g of methacrylate (crosslinking agent) and α
-39 g of methyl styrene dimer (chain transfer agent) was added and mixed uniformly, and then a releasing agent, an ultraviolet absorber and a polymerization initiator were added and mixed in the same manner as in (2) of Example 1 to obtain a liquid. A polymerizable mixture was prepared. (2) Using the polymerizable mixture obtained in the above (1),
A methacrylic resin material (plate-like molded product) having a thickness of 5 mm was manufactured in exactly the same manner as (3) of Example 1. (3) Using a test piece prepared from the methacrylic resin material (plate-like molded product) obtained in the above (2), the haze value was measured by the method described in the above (i), and the hot water resistance (boiling resistance) was measured. ), A molded article was prepared by the method described in (ii) above, and its thermoforming workability was evaluated. The results are as shown in Table 1 below. Further, during the production of the molded body, no defective portion such as a thinned portion or a crack was generated.

Example 4 (1) 13 kg of methyl methacrylate, 390 g of butyl acrylate, 52 g of ethylene glycol dimethacrylate (crosslinking agent) and 91 g of α-methylstyrene dimer (chain transfer agent) were added and uniformly mixed. Then, a release agent, an ultraviolet absorber and a polymerization initiator were further added and mixed in the same manner as in (1) of Example 1 to prepare a liquid polymerizable mixture. (2) Using the polymerizable mixture obtained in the above (1),
A methacrylic resin material (plate-like molded product) having a thickness of 5 mm was manufactured in exactly the same manner as (3) of Example 1. (3) Using a test piece prepared from the methacrylic resin material (plate-like molded product) obtained in the above (2), the haze value was measured by the method described in the above (i), and the hot water resistance (boiling resistance) was measured. ), A molded article was prepared by the method described in (ii) above, and its thermoforming workability was evaluated. The results are as shown in Table 1 below. Further, during the production of the molded body, no defective portion such as a thinned portion or a crack was generated.

Example 5 (1) To 10 kg of a syrup obtained by performing the same operation as in (1) of Example 1, 3 kg of methyl methacrylate, 910 g of lauryl methacrylate, 1,3-butylene glycol dimethacrylate ( 52 g of a crosslinking agent) and 65 g of an α-methylstyrene dimer (chain transfer agent) were added and mixed uniformly, and further, in the same manner as in Example 1, (2), a release agent, an ultraviolet absorber and a polymerization initiator A liquid polymerizable mixture was prepared by addition and mixing. (2) Using the polymerizable mixture obtained in the above (1),
A methacrylic resin material (plate-like molded product) having a thickness of 5 mm was manufactured in exactly the same manner as (3) of Example 1. (3) Using a test piece prepared from the methacrylic resin material (plate-like molded product) obtained in the above (2), the haze value was measured by the method described in the above (i), and the hot water resistance (boiling resistance) was measured. ), A molded article was prepared by the method described in (ii) above, and its thermoforming workability was evaluated. The results are as shown in Table 1 below. Further, during the production of the molded body, no defective portion such as a thinned portion or a crack was generated.

Example 6 (1) To 10 kg of a syrup obtained by performing the same operation as in (1) of Example 1, 3 kg of methyl methacrylate, 390 g of 2-ethylhexyl acrylate and α-methylstyrene dimer (chain (Transfer agent) 52 g was added and uniformly mixed, and then a release agent, an ultraviolet absorber and a polymerization initiator were added and mixed in the same manner as in Example 1 (2) to prepare a liquid polymerizable mixture. . (2) Using the polymerizable mixture obtained in the above (1),
A methacrylic resin material (plate-like molded product) having a thickness of 5 mm was manufactured in exactly the same manner as (3) of Example 1. (3) Using a test piece prepared from the methacrylic resin material (plate-like molded product) obtained in the above (2), the haze value was measured by the method described in the above (i), and the hot water resistance (boiling resistance) was measured. ), A molded article was prepared by the method described in (ii) above, and its thermoforming workability was evaluated. The results are as shown in Table 1 below. Further, during the production of the molded body, no defective portion such as a thinned portion or a crack was generated.

Comparative Example 1 (1) To 10 kg of a syrup obtained by performing the same operation as in (1) of Example 1, 3 kg of methyl methacrylate, 650 g of 2-ethylhexyl acrylate, 1,3-butylene glycol di 52 g of methacrylate (crosslinking agent) and 19.5 g of lauryl mercaptan (chain transfer agent) were added and uniformly mixed, and further, in the same manner as in Example 1 (2), a release agent, an ultraviolet absorber and polymerization initiation A liquid polymerizable mixture was prepared by adding the additives. (2) Using the polymerizable mixture obtained in the above (1),
A methacrylic resin material (plate-like molded product) having a thickness of 5 mm was manufactured in exactly the same manner as (3) of Example 1. (3) Using a test piece prepared from the methacrylic resin material (plate-like molded product) obtained in the above (2), the haze value was measured by the method described in the above (i), and the hot water resistance (boiling resistance) was measured. ), A molded article was prepared by the method described in (ii) above, and its thermoforming workability was evaluated. The results are as shown in Table 1 below. During the production of the molded body, there were no defective portions such as thinned portions and cracks.

Comparative Example 2 (1) To 10 kg of a syrup obtained by performing the same operation as in (1) of Example 1, 3 kg of methyl methacrylate, 390 g of 2-ethylhexyl acrylate, 1,3-butylene glycol di 52 g of methacrylate (crosslinking agent) and 19.5 g of lauryl mercaptan (chain transfer agent) were added and uniformly mixed, and further, in the same manner as in Example 1 (2), a release agent, an ultraviolet absorber and polymerization initiation A liquid polymerizable mixture was prepared by adding the additives. (2) Using the polymerizable mixture obtained in the above (1),
A methacrylic resin material (plate-like molded product) having a thickness of 5 mm was manufactured in exactly the same manner as (3) of Example 1. (3) Using a test piece prepared from the methacrylic resin material (plate-like molded product) obtained in the above (2), the haze value was measured by the method described in the above (i), and the hot water resistance (boiling resistance) was measured. ), A molded article was prepared by the method described in (ii) above, and its thermoforming workability was evaluated. The results are as shown in Table 1 below. During the production of the molded body, there were no defective portions such as thinned portions and cracks.

Comparative Example 3 (1) To 10 kg of a syrup obtained by performing the same operation as in (1) of Example 1, 3 kg of methyl methacrylate, 390 g of 2-ethylhexyl acrylate, 1,3-butylene glycol di 52 g of methacrylate (crosslinking agent) and 6.5 g of lauryl mercaptan (chain transfer agent) were added and uniformly mixed, and further, in the same manner as in (2) of Example 1, a releasing agent, an ultraviolet absorber and polymerization initiation A liquid polymerizable mixture was prepared by adding the additives. (2) Using the polymerizable mixture obtained in the above (1),
A methacrylic resin material (plate-like molded product) having a thickness of 5 mm was manufactured in exactly the same manner as (3) of Example 1. (3) Using a test piece prepared from the methacrylic resin material (plate-like molded product) obtained in the above (2), the haze value was measured by the method described in the above (i), and the hot water resistance (boiling resistance) was measured. ), A molded article was prepared by the method described in (ii) above, and its thermoforming workability was evaluated. The results are as shown in Table 1 below.

Comparative Example 4 (1) To 10 kg of syrup obtained by performing the same operation as in (1) of Example 1, 3 kg of methyl methacrylate, 650 g of 2-ethylhexyl acrylate and ethylene glycol dimethacrylate (crosslinking agent) ) 52 g was added and mixed uniformly, and a releasing agent, an ultraviolet absorber and a polymerization initiator were further added and mixed in the same manner as in (2) of Example 1 to prepare a liquid polymerizable mixture. (2) Using the polymerizable mixture obtained in the above (1),
A methacrylic resin material (plate-like molded product) having a thickness of 5 mm was manufactured in exactly the same manner as (3) of Example 1. (3) Using a test piece prepared from the methacrylic resin material (plate-like molded product) obtained in the above (2), the haze value was measured by the method described in the above (i), and the hot water resistance (boiling resistance) was measured. ), A molded article was prepared by the method described in (ii) above, and its thermoforming workability was evaluated. The results are as shown in Table 1 below. In the case of Comparative Example 4, the test piece was broken at the time of vacuum forming at 200 ° C., and molding was not possible.

Comparative Example 5 (1) To 10 kg of a syrup obtained by performing the same operation as in (1) of Example 1, 3 kg of methyl methacrylate, 650 g of 2-ethylhexyl acrylate, 1,3-butylene glycol di 52 g of methacrylate (crosslinking agent) and 6.5 g of lauryl mercaptan (chain transfer agent) were added and uniformly mixed, and further, in the same manner as in Example 1, (2), a releasing agent, an ultraviolet absorber and polymerization initiation A liquid polymerizable mixture was prepared by adding the additives. (2) Using the polymerizable mixture obtained in the above (1),
A methacrylic resin material (plate-like molded product) having a thickness of 5 mm was manufactured in exactly the same manner as (3) of Example 1. (3) Using a test piece prepared from the methacrylic resin material (plate-like molded product) obtained in the above (2), the haze value was measured by the method described in the above (i), and the hot water resistance (boiling resistance) was measured. ), A molded article was prepared by the method described in (ii) above, and its thermoforming workability was evaluated. The results are as shown in Table 1 below.

Comparative Example 6 (1) To 10 kg of a syrup obtained by performing the same operation as in (1) of Example 1, 3 kg of methyl methacrylate, 390 g of butyl acrylate, 1,3-butylene glycol dimethacrylate ( (Cross-linking agent) 52 g and 19.5 g of 2-mercaptoethanol (chain transfer agent) were added and uniformly mixed, and further, in the same manner as in Example 1, (2), a release agent, an ultraviolet absorber and a polymerization initiator A liquid polymerizable mixture was prepared by adding the additives. (2) Using the polymerizable mixture obtained in the above (1),
A methacrylic resin material (plate-like molded product) having a thickness of 5 mm was manufactured in exactly the same manner as (3) of Example 1. (3) Using a test piece prepared from the methacrylic resin material (plate-like molded product) obtained in the above (2), the haze value was measured by the method described in the above (i), and the hot water resistance (boiling resistance) was measured. ), A molded article was prepared by the method described in (ii) above, and its thermoforming workability was evaluated. The results are as shown in Table 1 below.

Comparative Example 7 (1) To 10 kg of a syrup obtained by performing the same operation as in (1) of Example 1, 3 kg of methyl methacrylate, 390 g of butyl acrylate, 1,3-butylene glycol dimethacrylate ( 52 g of a crosslinking agent) and 19.5 g of octyl mercaptan (chain transfer agent) were added and uniformly mixed, and a release agent, an ultraviolet absorber and a polymerization initiator were further added thereto in the same manner as in (2) of Example 1. The mixture was mixed to prepare a liquid polymerizable mixture. (2) Using the polymerizable mixture obtained in the above (1),
A methacrylic resin material (plate-like molded product) having a thickness of 5 mm was manufactured in exactly the same manner as (3) of Example 1. (3) Using a test piece prepared from the methacrylic resin material (plate-like molded product) obtained in the above (2), the haze value was measured by the method described in the above (i), and the hot water resistance (boiling resistance) was measured. ), A molded article was prepared by the method described in (ii) above, and its thermoforming workability was evaluated. The results are as shown in Table 1 below.

Comparative Example 8 (1) To 10 kg of a syrup obtained by performing the same operation as in (1) of Example 1, 3 kg of methyl methacrylate, 390 g of butyl acrylate, 1,3-butylene glycol dimethacrylate ( 52 g of cross-linking agent) and 65 g of carbon tetrabromide (chain transfer agent) were added and mixed uniformly, and then a releasing agent, an ultraviolet absorber and a polymerization initiator were added in the same manner as in (2) of Example 1. The mixture was mixed to prepare a liquid polymerizable mixture. (2) Using the polymerizable mixture obtained in the above (1),
A methacrylic resin material (plate-like molded product) having a thickness of 5 mm was manufactured in exactly the same manner as (3) of Example 1. (3) Using a test piece prepared from the methacrylic resin material (plate-like molded product) obtained in the above (2), the haze value was measured by the method described in the above (i), and the hot water resistance (boiling resistance) was measured. ), A molded article was prepared by the method described in (ii) above, and its thermoforming workability was evaluated. The results are as shown in Table 1 below.

Comparative Example 9 (1) To 10 kg of syrup obtained by performing the same operation as in (1) of Example 1, 3 kg of methyl methacrylate, 650 g of butyl acrylate, 1,3-butylene glycol dimethacrylate ( 52 g of a crosslinking agent) and 6.5 g of a terpinolene (chain transfer agent) are added and uniformly mixed, and further mixed with a releasing agent, an ultraviolet absorber and a polymerization initiator in the same manner as in Example 1 (2). Thus, a liquid polymerizable mixture was prepared. (2) Using the polymerizable mixture obtained in the above (1),
A methacrylic resin material (plate-like molded product) having a thickness of 5 mm was manufactured in exactly the same manner as (3) of Example 1. (3) Using a test piece prepared from the methacrylic resin material (plate-like molded product) obtained in the above (2), the haze value was measured by the method described in the above (i), and the hot water resistance (boiling resistance) was measured. ), A molded article was prepared by the method described in (ii) above, and its thermoforming workability was evaluated. The results are as shown in Table 1 below. In the case of Comparative Example 4, the test piece was broken at the time of vacuum forming at 200 ° C., and molding was not possible.

Comparative Example 10 (1) To 10 kg of a syrup obtained by performing the same operation as in (1) of Example 1, 3 kg of methyl methacrylate, 390 g of butyl acrylate, 1,3-butylene glycol dimethacrylate ( 52 g of a crosslinking agent) and 6.5 g of a terpinolene (chain transfer agent) are added and uniformly mixed, and further mixed with a releasing agent, an ultraviolet absorber and a polymerization initiator in the same manner as in Example 1 (2). Thus, a liquid polymerizable mixture was prepared. (2) Using the polymerizable mixture obtained in the above (1),
An attempt was made to produce a methacrylic resin material (plate-like molded product) having a thickness of 5 mm in exactly the same manner as (3) of Example 1, but the polymerization inhibition was large, the polymerization rate in the first stage was low, and the At the time of polymerization, a foam was generated, resulting in a methacrylic resin material (plate-like molded product) having poor appearance. Therefore, in Comparative Example 10, the tests for hot water resistance and thermoforming workability were stopped.

[0050]

[Table 1]

From the results in Table 1 above, it is clear that α, together with methyl methacrylate, alkyl (meth) acrylate (b) and optionally polyhydric (meth) acrylate,
-Methylstyrene dimer (chain transfer agent) is converted to methyl methacrylate and alkyl (meth) acrylate (b)
The methacrylic resin materials of Examples 1 to 6 obtained by using the amount in the range of 0.05 to 2% by weight based on the total weight of
That is, the methacrylic resin material of the present invention having the structural unit (a), the structural unit (b), the structural unit (c) and, in some cases, the structural unit (d) in an amount within the range specified in the present invention is a hot water of 95 ° C. Even after being immersed for 300 hours, its haze value is extremely small, and it has excellent hot water resistance,
In addition, it is excellent in thermoforming workability, and when deep drawing is performed by vacuum forming, the dimensions (curvature radius) of the bent part completely match the dimensions in the vacuum forming die, and the desired shape and dimensions are adjusted. It can be seen that a molded article having the same can be manufactured with high dimensional accuracy.

On the other hand, Comparative Examples 1-2 obtained by using a chain transfer agent comprising a mercaptan compound or carbon tetrabromide in the range of 0.05 to 2% by weight specified in the present invention. Also, the methacrylic resin materials of Comparative Examples 6 to 8 show that the haze value is significantly increased after being immersed in hot water at 95 ° C. for 300 hours, is whitened, and is inferior in hot water resistance. Comparative Examples 3, 5, and 9 using a mercaptan compound or a terpinolene chain transfer agent in an amount smaller than the amount specified in the present invention, and Comparative Examples not using a chain transfer agent It can be seen that the methacrylic resin material obtained in No. 4 is inferior in thermoforming processability, and that a molded product having the shape and dimensions of a vacuum mold cannot be obtained. Furthermore, in the case of Comparative Example 10 using terpinolene as a chain transfer agent, it can be seen that the polymerization reaction did not proceed smoothly and a methacrylic resin material was not obtained.

Example 7 (1) Using the methacrylic resin material (plate-shaped molded product) obtained in (3) of Example 1 in the above (ii) (evaluation of thermoforming workability) A molded article (molded article for a bathtub model) shown in FIG. 1 was manufactured in exactly the same manner as described above, and a glass fiber mat (Nittobo Co., Ltd., “#
450 "), and cover with an unsaturated polyester resin (" Polylite LP9 "manufactured by Dainippon Ink Co., Ltd.).
24 ") 100 parts of a methyl ethyl ketone peroxide-containing liquid (concentration 55% by weight; Nippon Oil & Fats Co., Ltd." Permec N ") 1.5 parts was added and uniformly applied at a rate of 700 g / m ^2. After gelling at a temperature of 20 ° C. (gelling time about 15 minutes), curing (curing time about 4 hours), heating to 60 ° C. and heating for 60 minutes to reinforce the outside of the molded body A molded article (bath) was produced. (2) The inside of the laminated molded article (bath) obtained in the above (1) was filled with water up to a position 5 cm from the upper end thereof, heated to a water temperature of 93 ° C., and kept at that temperature for 500 hours. Thereafter, the hot water was drained and the occurrence of cracks was visually observed, but no whitening occurred.

<< Comparative Example 11 >> (1) Using the methacrylic resin material (plate-like molded product) obtained in (2) of Comparative Example 1, the above (ii) (evaluation of thermoforming workability) A molded article (molded article for a bathtub model) shown in FIG. 1 was produced in exactly the same manner as in Example 1, and the entire outside (back side) of the unsaturated polyester resin reinforced with a glass fiber mat was carried out in the same manner as in Example 1. To form a laminated molded article (bath) having a hardened layer formed from the above and reinforced on the outside. (2) The inside of the laminated molded article (bath) obtained in the above (1) was filled with water up to a position 5 cm from the upper end thereof, heated to a water temperature of 93 ° C., and kept at that temperature for 500 hours. Thereafter, the hot water was drained, and the occurrence of cracks was visually observed. As a result, the surface in contact with the hot water was whitened, and the commercial value was significantly reduced.

[0055]

The methacrylic resin material of the present invention is excellent in thermoformability, and its purpose is to produce a molded article having a curved portion by drawing or bending under heating. Molding without cracking
It can be manufactured well with high dimensional accuracy. further,
The methacrylic resin material of the present invention has excellent hot water resistance and wet heat resistance, and does not cause troubles such as haze, whitening, cracks, and blisters even when exposed to hot water or heated steam for a long period of time. And, according to the production method of the present invention,
A methacrylic resin material having the above-mentioned excellent characteristics can be produced smoothly. The methacrylic resin material of the present invention, taking advantage of the above-described excellent properties, a bathroom, a bathtub,
In the sanitary fields such as washrooms and toilets,
It can be effectively used for kitchen products such as a top plate of a system kitchen, interior and exterior materials of a house, and other various uses.

[Brief description of the drawings]

FIG. 1 is a view showing the shape and structure of a molded article produced for evaluating thermoforming workability and hot water resistance in Examples and Comparative Examples of the present invention.

Claims (6)

[Claims] (I) a structural unit (a) derived from methyl methacrylate, an alkyl methacrylate having an alkyl group having 2 to 20 carbon atoms, and an alkyl acrylate having an alkyl group having 1 to 20 carbon atoms Methacryl having a structural unit (b) derived from at least one alkyl (meth) acrylate selected from esters and a structural unit (c) derived from an α-methylstyrene dimer optionally substituted with a benzene nucleus (Ii) a weight ratio of the structural unit (a) to the structural unit (b) is 8;
(Iii) {the total weight of the structural unit (a) and the structural unit (b)}: {the weight of the structural unit (c)} is 100: 0.0.
5 to 2; a methacrylic resin material. 2. It has a structural unit (d) derived from a (meth) acrylic acid polyvalent ester in a proportion of 5% by weight or less based on the total weight of the structural unit (a) and the structural unit (b). The methacrylic resin material according to claim 1, wherein 3. The methacrylic resin material according to claim 1, which is used for sanitary products. (I) (a) methyl methacrylate,
(B) alkyl methacrylate having 2 to 20 carbon atoms in the alkyl group and 1 to 2 carbon atoms in the alkyl group;
A polymerizable mixture containing at least one alkyl (meth) acrylate selected from alkyl acrylates which is 0 and (c) an α-methylstyrene dimer optionally substituted with a benzene nucleus, or methyl methacrylate And / or the polymerizable mixture containing a polymer comprising the alkyl (meth) acrylate, wherein (ii) the weight ratio of the methyl methacrylate component to the alkyl (meth) acrylate component is 80:
(Iii) {the total weight of the methyl methacrylate component and the alkyl (meth) acrylate component}: {the weight of the α-methylstyrene dimer component} is 100: 0. A method for producing a methacrylic resin material, comprising polymerizing a polymerizable mixture having a molecular weight of 0.5 to 2 using a polymerization initiator. 5. A polymerizable mixture comprising (d) a (meth) acrylic acid polyvalent ester component in an amount of 5% by weight or less based on the total weight of the methyl methacrylate component and the alkyl (meth) acrylate component. Further containing
The method according to claim 4. 6. A sanitary molded article comprising the methacrylic resin material according to claim 1.