JPH083224A - Method for producing methacrylic resin plate for sanitary - Google Patents

Abstract

PURPOSE:To produce a sanitary plate excellent in fabricability, etc., by dissolving a methacrylic resin having a specified mol.wt. in a methacrylic monomer, pouring the resultant syrup into a cell, and polymerizing the syrup. CONSTITUTION:A methacrylic resin in an amount of 5-50 pts.wt. (e.g. polymethyl methacrylate) having a viscosity-average mol.wt. of 10,000-300,000 is dissolved in 100 pts.wt. methacrylic monomer (e.g. methyl methacrylate), thus giving a syrup. After being mixed with a free-radical polymn. initiator (e.g. benzoyl peroxide), the syrup is poured into a cell and polymerized. The cell constructed from two glass or metal plates, a soft sealant, and clamps can be used, and a continuous cell comprising two continuous stainless steel belts is also usable. Thus, a methacrylic resin plate for sanitary goods, such as a bathtub, can be produced stably and easily.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an acrylic resin plate suitable for sanitary applications such as bathtubs and washbasins.

[0002]

2. Description of the Related Art Many sanitary products such as bathtubs and washbasins are made of resin. Conventionally, FRP made of unsaturated polyester has often been used as these resin materials, but recently, unsaturated polyester-based materials have drawbacks such as yellowing over time and easy scratching. A methacrylic resin-based material for sanitary products, which has characteristics of being less likely to yellow and less likely to be scratched, has been proposed, and a part thereof is being put to practical use.

As a concrete example, Japanese Patent Laid-Open No. 54-60
No. 90 discloses a crosslinkable compound 0.01 to 1 containing 0.2 to 8 mol% of a specific non-crosslinkable acrylic acid ester in methyl methacrylate and two or more (meth) acryloyl groups.
There is a proposal of a methacrylic resin plate-shaped molded product obtained by polymerizing and solidifying a mixture of mol%. In addition, JP-A-60-197
No. 707, 0.01 to 2 wt% of a chain transfer agent is added to methyl methacrylate alone or a monomer mixture of methyl methacrylate and an acrylate ester to carry out prepolymerization to produce a syrup. A proposal of a method for producing an acrylic resin sheet having excellent thermoforming processability and solvent resistance by adding 0.02 to 1% by weight of a crosslinking agent to the obtained syrup and performing cast polymerization in a mold is made. is there.

[0004]

Problems to be Solved by the Invention JP-A-54-6090
Although the methacrylic resin plate obtained by the method described in JP-A No. 1993-115 is excellent in heat resistance, solvent resistance, adhesiveness, etc., it is low in moldability for thermoforming for sanitary. On the other hand, the prepolymerization reaction in which a chain transfer agent for producing a syrup in the method disclosed in JP-A-60-197707 is added is unstable, and the polymerization is caused by slight fluctuations in conditions such as a heating temperature, a stirring state and a polymerization time. It is not easy to stably obtain a resin having a predetermined molecular weight and a predetermined polymerization rate because of large fluctuations in the rate and the molecular weight, and this tendency becomes even greater when a syrup having a particularly high polymerization rate is to be obtained.

Therefore, the present invention provides a method for stably and easily producing a methacrylic resin plate for sanitary which is excellent in processability.

[0006]

According to the present invention, the viscosity average molecular weight is about 10 parts by weight per 100 parts by weight of methacrylic monomer.
It is a method for producing a methacrylic resin plate for sanitary, which comprises dissolving 5 to 50 parts by weight of methacrylic resin of 000 to about 300,000 to form a syrup, and injecting the syrup into a cell to polymerize.

The methacrylic monomer in the present invention is a monomer mixture containing methyl methacrylate as a main component and optionally a copolymerizable comonomer.

Specific examples of comonomers include alkyl acrylates such as methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate and isononyl acrylate; ethylene glycol dimethacrylate, tetra Ethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, neopentyl glycol diacrylate, hexanediol dimethacrylate, nonanediol dimethacrylate, trimethylolpropane trimethacrylate, 2,2-bis [4 (methacryloylpolyoxyethyl) phenyl] propane, Two in the molecule of phthalic acid bis (2-methacryloyloxyethyl) ester, allyl methacrylate, divinylbenzene, diallyl phthalate, etc. Polyfunctional monomers having a radical polymerizable group above; cyclohexyl methacrylate, ethyl methacrylate, phenyl methacrylate, methacrylic acid, maleic anhydride, styrene, cyclohexyl maleimide, there is acrylonitrile.

These comonomers are appropriately selected depending on the application of the resin plate to be obtained. If particularly high moldability is required, the acrylic ester may be used within the range of 10% by weight in the monomer. When high chemical resistance and heat resistance are required, polyfunctional monomers having two or more radically polymerizable groups in the molecule may be used within the range of 0.005 to 5% by weight in the monomers. .

In the present invention, the methacrylic resin dissolved in the methacrylic monomer has a viscosity average molecular weight within the range of about 10,000 to about 300,000. The viscosity average molecular weight is preferably 50,000 to 2,000.
00, more preferably 70,000 to 150
The range is 000. By adding a methacrylic resin having a molecular weight in this range, the processability of the obtained resin plate during thermoforming can be improved. When the viscosity average molecular weight is about 10,000 or less, the processability of the obtained resin is good, but the mechanical properties are low, which is not preferable. Further, those having a viscosity average molecular weight of more than about 300,000 are not preferable because the processability becomes low.

The methacrylic resin as used herein means a resin having a methyl methacrylate unit as a main component, and in addition to methyl methacrylate homopolymer, methyl methacrylate and alkyl acrylate, styrene, methacrylic acid. It also includes a copolymer with a comonomer such as.

The amount of the methacrylic resin is 5 to 50 parts by weight, preferably 10 to 40 parts by weight, based on 100 parts by weight of the methacrylic monomer mixture. If this amount is too small, the moldability will be poor, and if it is too large, the viscosity of the syrup will be too high and it will be difficult to handle.

In the present invention, the syrup may be prepared by dissolving the methacrylic resin in the methacrylic monomer, and the method is not specified. The methacrylic resin is preferably used in the form of powder, pellets or the like in the form of particles having an average size of 10 mm or less so that it can be easily dissolved in the methacrylic monomer.

The syrup thus obtained is also superior in storage stability to that obtained by prepolymerization. If the obtained syrup is heated at the time of dissolution, it is cooled to about room temperature. It can be immediately subjected to polymerization, but since it has excellent storage stability, it can be stored at room temperature or lower and used when necessary.

A radical polymerization initiator is added to the syrup when it is subjected to polymerization. As the radical polymerization initiator, a usual polymerization initiator used for producing a methacrylic resin plate can be used. For example, lauroyl peroxide, benzoyl peroxide, di-t-butyl peroxide, t-butyl peroxy 2-ethylhexanoate, t
Peroxide initiators such as butylperoxyisobutyrate, t-butylperoxypivalate, t-butylperoxybenzoate, t-butylperoxyacetate, diisopropylperoxydicarbonate, disec-butylperoxydicarbonate; 2, Azo-based initiators such as 2'azobisisobutyronitrile and 2,2'azobis (2,4-dimethylvaleronitrile); further mainly peroxide initiators and reducing compounds such as amines and mercaptans A known redox type initiator system or the like combined as a component can be exemplified.

In addition to the above, known additives such as an antioxidant, an ultraviolet absorber, a chain transfer agent, a release agent, a dye, a pigment, etc. may be used depending on the application, as long as the characteristics of the resin of the present invention are not impaired.
It is also possible to add inorganic fillers and the like.

The syrup is injected into a cell and polymerized by a known so-called cell casting method. That is, as the cell, for example, a cell composed of two glass plates or a metal plate, a soft sealing material and a clamp can be used, and a continuous cell using two stainless continuous belts can also be used. The cell thickness is selected so as to obtain a desired resin plate, but is generally in the range of 1 to 30 mm. As a heating method in the polymerization, a known method, for example, hot air, hot water, a heat source such as an infrared heater is used. The polymerization conditions are appropriately selected depending on the type and amount of the initiator used and the composition of the monomer mixture, but generally the polymerization is performed at 50 to 120 ° C. for 1 to several tens of hours. After completion of the polymerization, the frame is opened to obtain a methacrylic resin plate.

[0018]

According to the present invention, a methacrylic resin plate for sanitary can be stably and easily produced. The resin plate obtained by the present invention has a low tensile strength at the time of thermoforming and a large elongation at break, so that a deep-drawn molded product such as a bathtub can be easily molded. That is, the resin plate obtained by the present invention has good workability for processing into sanitary products such as bathtubs and wash bowls.

[0019]

EXAMPLES The present invention will be specifically described below with reference to examples.
In addition, the part in an Example and a comparative example represents a weight part. Also,
The physical property measurements and test methods carried out in the examples are as follows. -Viscosity average molecular weight: The intrinsic viscosity [η] was obtained using an Ubbelohde viscometer, and the viscosity average molecular weight M was obtained from the following equation. lnM = {ln [η] -ln (4.8 × 10 -5)} /
0.8 • Tensile test: J according to JIS K-7113
Using the IS2 test piece, the test piece was preheated to 160 ° C., and a tensile test was performed under the condition of a crosshead speed of 500 mm / min to determine the elongation at break.・ Vacuum formability: A square mold with a bottom surface of 280 mm x 280 mm, a depth of 70 mm, and a radius of curvature R = 5 mm at the boundary between the bottom surface and the side surface is set in a vacuum forming device with a slide-type infrared heater, and the surface is set. The sheet was vacuum-formed by heating to a temperature of 180 ° C., and the formability was evaluated by the magnitude of R on the side of the molded product.・ Backing test by FRP: Backing of the molded product obtained by the vacuum moldability test is performed by a hand lay-up method using a glass fiber mat and an unsaturated polyester resin, and the appearance of the adhesive surface after curing is abnormal. And the adhesion was visually determined.・ Storage stability of syrup: Syrup is stored at room temperature for 1 month and checked for changes.
The one in which the viscosity was remarkably increased or the polymerization was solidified was designated as x.

Example 1 Methyl methacrylate 93.3% by weight, 2-ethylhexyl acrylate 6.2% by weight, diallyl phthalate 0.
A monomer composed of 5% by weight was placed in a glass container and stirred at a temperature of 60 ° C., and 98% by weight of a methyl methacrylate unit obtained by a suspension polymerization method, 2% by weight of a methyl acrylate unit, a viscosity average molecular weight of about 12 Twenty-five parts of powdery methacrylic resin was added to 24 parts by weight with respect to 100 parts by weight of the monomer and dissolved for 2 hours to obtain a syrup. The syrup showed no change in viscosity even after being left at room temperature for one month, and had a storage stability of O. To 100 parts by weight of this syrup, 0.1% by weight of 2,2'azobisisobutyronitrile as a radical polymerization initiator was added and dissolved, and then degassed.
Inject into a 5 mm thick cell composed of a glass plate and a vinyl chloride resin gasket, and pour at 65 ° C for 4 hours, then 1
Polymerization was carried out at 20 ° C. for 1 hour. The elongation at break in the tensile test of the obtained plate was 700%. Also, the radius R of the side in the vacuum formability test was 14 mm. Furthermore, a molded product obtained by the vacuum formability test was used to perform a backing test by FRP. As a result, the appearance was not abnormal and the adhesion was good.

Examples 2 to 4 The same procedure as in Example 1 was carried out except that a monomer having the composition shown in Table 1 and a methacrylic resin were used. Table 2 shows the evaluation results.

[0022]

[Table 1]

Comparative Example 1 Methyl methacrylate was added with 20 ppm of 2,2′azobisisobutyronitrile and prepolymerized at 70 ° C. to obtain a syrup containing 5% by weight of a polymer having a viscosity average molecular weight of 1,500,000. Obtained. This syrup 94.5 parts by weight, 2 ethylhexyl acrylate 5 parts by weight, diallyl phthalate 0.
5 parts by weight and 0.1 parts by weight of azobisisobutyronitrile as a radical polymerization initiator were mixed and dissolved, and polymerization was carried out by the same method as in Example 1. Table 2 shows the evaluation results of the obtained plate and the storage stability of the syrup.

Comparative Example 2 96.5 parts by weight of methyl methacrylate, 3.5 parts by weight of 2-ethylhexyl acrylate, 2,2'azobis (2,4
-Dimethylvaleronitrile) 0.1 part by weight and lauryl mercaptan 0.08 part by weight at 90 ° C for 2 hours.
Prepolymerization was carried out for a time to obtain a syrup having a polymerization rate of 25%. The viscosity average molecular weight of the polymer contained in this syrup was about 80,000. To 100 parts by weight of this syrup, 0.15 parts by weight of ethylene glycol dimethacrylate, 2,2 '
0.1 part by weight of azobisisobutyronitrile was added, and polymerization was carried out in the same manner as in Example. Table 2 shows the evaluation results of the obtained plate and the storage stability of the syrup.

Comparative Example 3 Syrup containing 5% by weight of a polymer having a viscosity average molecular weight of 1,500,000 by adding 20 ppm of 2,2′azobisisobutyronitrile to methyl methacrylate and prepolymerizing at 70 ° C. Got 100 parts by weight of this syrup and 0.1 parts by weight of 2,2′azobisisobutyronitrile as a radical polymerization initiator were mixed and dissolved, and polymerization was carried out by the same method as in Example 1. Table 2 shows the evaluation results of the obtained plate and the storage stability of the syrup.

[0026]

[Table 2]

Claims (1)

[Claims] 1. A sanitary product in which 5 to 50 parts by weight of a methacrylic resin having a viscosity average molecular weight of about 10,000 to about 300,000 is dissolved in 100 parts by weight of a methacrylic monomer to prepare a syrup, and the syrup is injected into a cell for polymerization. Method for producing methacrylic resin plate.