JP2001131296A - Methacrylic resin plate for manufacturing sanitary supplies and its making method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide methacrylic resin plates for manufacturing sanitary supplies which excel in peel resistance between a methacrylic resin article and a glass fiber-containing unsaturated polyester and, simultaneously, excel in moldability. SOLUTION: The methacrylic resin plates for manufacturing sanitary supplies have an elongation at break of >=700% and, at the same time, a creep index of <=1×106 Pa.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a methacrylic resin plate for manufacturing sanitary articles, such as a bathtub or a washbasin, and a method for manufacturing the resin plate.

[0002]

2. Description of the Related Art JP-A-8-3224 discloses a method for producing a methacrylic resin plate for producing sanitary articles.
(1) a step of dissolving 5 to 50 parts by weight of a methacrylic resin having a viscosity average molecular weight of about 10,000 to about 300,000 in 100 parts by weight of a methacrylic monomer to obtain a syrup; and (2) injecting the syrup into a cell and polymerizing the syrup. A methacrylic resin plate to obtain a methacrylic resin plate. As a method of manufacturing a sanitary article from the methacrylic resin plate obtained by this manufacturing method, after forming the methacrylic resin plate into a methacrylic resin molded product having a desired shape by a thermoforming method exemplified by vacuum forming or pressure forming, In order to reinforce the molded article, a method of backing the molded article with an unsaturated polyester resin containing glass fiber is known.

[0003]

However, the above methacrylic resin plate has a reduced thickness because the methacrylic resin molded product is stretched by backing, and the stretched molded product has a reduced thickness. Because the force to return to the original shape acts, in sanitary goods where contact with high-temperature water and drying are repeated alternately, for example, in a bathtub, the unsaturated polyester resin containing glass fibers and the molded product peel off. There is a problem that it is easy. Incidentally, when peeling occurs, not only does the appearance of the sanitary article deteriorate, but also the strength of the sanitary article significantly decreases. Therefore, the object of the present invention is, even when backed with an unsaturated polyester resin containing glass fibers, a molded article made of methacrylic resin, excellent in peel resistance between the unsaturated polyester resin containing glass fibers, and Another object of the present invention is to provide a methacrylic resin plate for producing sanitary articles excellent in moldability and a method for producing the resin plate.

[0004]

Means for Solving the Problems The present inventors have continued research on a methacrylic resin plate which does not have the above problems. As a result, (1) a methacrylic resin plate having a specific elongation at break and a creep index does not have the above-mentioned problems, and (2) a specific amount of a methyl methacrylate-based polymer having a specific viscosity average molecular weight. And a specific amount of a methyl methacrylate-based monomer, a specific amount of a polyfunctional monomer copolymerizable with the monomer, and a specific amount of a chain transfer agent. It has been found that the present invention has no point, and the present invention has been completed.

That is, according to the present invention, the elongation at break is 700
% Or more and a creep index of 1 × 10 ⁶ Pa or less is a methacrylic resin plate for manufacturing sanitary products.

The present invention is also a method for producing a methacrylic resin plate for producing sanitary articles, comprising the following steps. Step-1: 5-35 parts by weight of a methyl methacrylate-based polymer having a viscosity average molecular weight of 50,000 to 300,000, 65 to 95 parts by weight of a methyl methacrylate-based monomer, and polyfunctionality copolymerizable with the methyl methacrylate-based monomer Monomer 0.1-0.5
Parts by weight, and 80% by weight or more of a chain transfer agent comprising an alkyl mercaptan, and a molar ratio of the alkyl mercaptan to the polyfunctional monomer in the chain transfer agent is 1.5 to 3.5. Step of mixing a chain transfer agent with 0.01 to 0.30 parts by weight to obtain a mixture (the total amount of the methyl methacrylate-based polymer and the methyl methacrylate-based monomer is 100 parts by weight, and a polyfunctional monomer and (The ratio of each of the chain transfer agents is based on 100 parts by weight.) Step-2: a step of injecting the mixture into a cell Step-3: a step of polymerizing the mixture injected into a cell Step-4: Step of removing from cell

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The "sanitary articles" according to the present invention mean water-supply articles such as bathtubs, wash bowls, wash basin members, unit bath constituent materials, kitchen articles and the like. Further, the "methacrylic resin plate" according to the present invention,
It means a resin plate containing a structural unit derived from a methyl methacrylate monomer as a main structural unit.
As the methacrylic resin plate, a resin plate obtained by the above production method is preferable. The size and thickness of the resin plate are not limited and may be determined according to the size of the sanitary article, and the thickness is generally about 0.1 to about 30 mm.

The “elongation at break” according to the present invention is defined by JI
It means the elongation at break determined by a tensile test at 160 ° C. in accordance with SK-7113 (for details of the measuring method, see below). Incidentally, this temperature substantially corresponds to the temperature at the time of thermoforming the methacrylic resin plate of the present invention. Since the elongation at break of the methacrylic resin sheet for manufacturing sanitary articles of the present invention is as large as 700% or more, preferably 800% or more, the resin sheet can be easily formed into a deep drawn product such as a bathtub.

The "creep index" according to the present invention means a time-η slope value (Pa) obtained by creep measurement (for details of the measurement method, see below). Since the creep index of the methacrylic resin plate of the present invention is 1 × 10 ⁶ Pa or less, the molded methacrylic resin plate has a small force to return to its original shape, and therefore has excellent peel resistance.

The "stress relaxation index" according to the present invention means an index determined by stress relaxation measurement (for details of the measurement method, see below). Since the stress relaxation index of the methacrylic resin sheet of the present invention is preferably 0.07 or less, and more preferably 0.035 or less, the molded methacrylic resin sheet has a faster relaxation of the residual strain, and thus has an excellent resistance to heat. Has peelability.

The method for producing the methacrylic resin plate for producing sanitary articles of the present invention is not particularly limited, and the above-mentioned method can be exemplified as a preferred production method.

The term "methyl methacrylate polymer" used in the present invention means a homopolymer of methyl methacrylate or a copolymer of methyl methacrylate and a comonomer copolymerizable with the monomer. .

As the comonomer, methyl acrylate,
Acrylic esters exemplified by ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, isononyl acrylate, cyclohexyl acrylate and phenyl acrylate; methyl methacrylate, ethyl methacrylate, methacrylic acid n-
Methacrylates exemplified by butyl, isobutyl methacrylate, 2-ethylhexyl methacrylate, isononyl methacrylate, cyclohexyl methacrylate and phenyl methacrylate; methacrylic acid; maleic anhydride; styrene; cyclohexylmaleimide; acrylonitrile; Acrylate, ethylene glycol dimethacrylate, tetraethylene glycol diacrylate, tetraethylene glycol methacrylate, neopentyl glycol dimethacrylate, neopentyl glycol diacrylate, hexanediol diacrylate, hexanediol dimethacrylate, nonanediol diacrylate, nonanediol dimethacrylate, Trimethylolpropane triacrylate, trime Roll propane dimethacrylate,
Polyfunctional monomers having two or more radically polymerizable groups in the molecule, exemplified by bis (2-methacryloyloxyethyl) phthalate ester and allyl methacrylate;
Can be exemplified. Two or more of these comonomers may be used in combination.

The comonomer may be appropriately selected depending on the molding conditions of the obtained methacrylic resin plate and the intended use. In particular, when excellent peel resistance is required, the amount of the monofunctional comonomer may be reduced or the amount of the polyfunctional monomer may be increased. When particularly excellent moldability is required for the obtained methacrylic resin plate, the amount of the monofunctional comonomer may be increased or the amount of the polyfunctional monomer may be decreased. The amount of the comonomer to be used is preferably 0.5 to 15% by weight, more preferably 0.5 to 12% by weight, with the total amount of methyl methacrylate and the comonomer being 100% by weight. If the amount of the comonomer is out of the above range, the resulting methacrylic resin plate tends to have poor moldability and peel resistance.

The "viscosity average molecular weight" of the methyl methacrylate polymer used in the present invention means the molecular weight M obtained by the following formula (1). lnM = {ln [η] -ln (4.8 × 10 −5)} / 0.8 (1) (where, M is the viscosity average molecular weight, and [η] is the intrinsic viscosity measured using an Ubbelohde viscometer. )

The viscosity-average molecular weight of the methyl methacrylate polymer is from 50,000 to 300,000. If the molecular weight is smaller than 50,000, the peeling resistance tends to deteriorate, and if it is larger than 300,000, the moldability tends to deteriorate. The amount of the methyl methacrylate polymer to be used is 5 to 35 parts by weight, based on 100 parts by weight of the total amount of the methyl methacrylate polymer and the methyl methacrylate monomer. If the amount is less than 5 parts by weight, the peel resistance tends to decrease. On the other hand, if the amount is more than 35 parts by weight, the viscosity of the mixture obtained in the step-1 becomes too high to make it difficult to handle, and at the same time, the moldability tends to deteriorate.

The term "methyl methacrylate-based monomer" used in the present invention means a mixture of a methyl methacrylate monomer and a comonomer copolymerizable with the monomer, mainly containing a methyl methacrylate monomer. The proportion of the comonomer in the methyl methacrylate-based monomer is not limited, and a mixture in which 0.5 to 15 parts by weight of 65 to 95 parts by weight of the methyl methacrylate-based monomer is a comonomer is preferable. If the proportion of the comonomer is too small, the moldability tends to deteriorate, and if it is too large, the peel resistance tends to deteriorate.

Comonomers copolymerizable with the methyl methacrylate monomer include methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate,
Acrylates exemplified by 2-ethylhexyl acrylate, isononyl acrylate, cyclohexyl acrylate and phenyl acrylate; methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, Methacrylic esters exemplified by isononyl methacrylate, cyclohexyl methacrylate and phenyl methacrylate; methacrylic acid; maleic anhydride; styrene; cyclohexylmaleimide; and acrylonitrile. Of these, acrylic esters are particularly preferred. Two or more of these comonomers may be used in combination.

The method for producing the mixture obtained in the step 1 is not limited, and the method for producing the mixture includes a mixture of a methyl methacrylate-based polymer and a methyl methacrylate-based monomer (hereinafter also referred to as “syrup”). A production method of adding a functional monomer or a chain transfer agent is preferred. The method for producing the syrup is not limited, and examples of the method for producing the syrup include a known production method in which a methyl methacrylate polymer is dissolved in a methyl methacrylate monomer and mixed. In order to increase the solubility of the methyl methacrylate polymer, the average particle diameter is about 0.1 μm or more.
It is preferable to use a powdery methyl methacrylate polymer of about 1 mm or a pellet having an average particle diameter of about 10 mm or less. As another method for producing syrup, a method in which a mixture of a methyl methacrylate-based monomer and a radical polymerization initiator is heated to partially polymerize the monomer can be exemplified.

The "polyfunctional monomer" used in the present invention means a monomer having two or more radically polymerizable groups in a molecule. As a polyfunctional monomer,
Ethylene glycol diacrylate, ethylene glycol dimethacrylate, tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, neopentyl glycol diacrylate, hexanediol diacrylate, hexanediol dimethacrylate, nonanediol diacrylate, nonane Diol dimethacrylate, trimethylolpropane triacrylate,
Examples include trimethylolpropane dimethacrylate, bis (2-methacryloyloxyethyl) phthalate, and allyl methacrylate. Of these, neopentyl glycol dimethacrylate and neopentyl glycol diacrylate are particularly preferred. Two or more polyfunctional monomers may be used in combination.

The amount of the polyfunctional monomer used is syrup 1
It is 0.1 to 0.5 part by weight based on 00 parts by weight. When the amount is less than 0.1 part by weight, the crosslinked structure of the obtained resin plate tends to be insufficient, and as a result, the peel resistance tends to decrease. If the amount is more than 0.5 part by weight, the crosslinked structure becomes too dense, and the moldability tends to deteriorate.

As the chain transfer agent used in the present invention, alkyl mercaptans exemplified by lauryl mercaptan, octyl mercaptan and butyl mercaptan; thioglycolic acid esters exemplified by thioglycolic acid-2-ethylhexyl and ethyl thioglycolate Β-mercaptopropionic esters exemplified by octyl β-mercaptopropionate; β-mercaptopropionic acid; and thiophenol and p (t-
(Butyl) thiophenol, and aromatic mercaptans. Of these, alkyl mercaptans are preferred. Two or more chain transfer agents can be used in combination. From the viewpoint of peel resistance, it is preferred that 80% by weight or more of the chain transfer agent used is an alkyl mercaptan.

The amount of the chain transfer agent to be used is 0.01 to 0.30 parts by weight based on 100 parts by weight of the syrup. If the amount is less than 0.01 part by weight, moldability is likely to deteriorate,
If the amount is more than 0.30 parts by weight, the peel resistance tends to deteriorate. When the molar ratio between the alkyl mercaptan and the polyfunctional monomer in the chain transfer agent is 1.5 to 3.5, both moldability and peel resistance are excellent. When a polyfunctional monomer and a chain transfer agent are added to a syrup and subjected to polymerization, a radical polymerization initiator is added to the syrup. The type of the radical polymerization initiator to be used is not limited, and may be any polymerization initiator that is usually used in the production of a methacrylic resin plate, and specifically,
Lauroyl peroxide, benzoyl peroxide, di-t-butyl peroxide, t-butylperoxy-2-ethylhexanoate, t-butylperoxyisobutyrate, t-butylperoxypivalate,
peroxide initiators exemplified by t-butylperoxybenzoate, t-butylperoxyacetate, diisopropylperoxydicarbonate and di-sec-butylperoxydicarbonate; 2,2'-azobisisobutyro Azo initiators exemplified by nitriles and 2,2′-azobis (2,4-dimethylvaleronitrile); and peroxide initiators, and reducing compounds exemplified by amines and mercaptans (main components) And redox initiators in combination with the above. The amount of the radical polymerization initiator used may be about 0.0001 to about 5 parts by weight based on 100 parts by weight of the syrup.

Each of the components used in the step-1 may be an antioxidant,
It may be used in combination with additives exemplified by ultraviolet absorbers, release agents, dyes, pigments and inorganic fillers. As the release agent, a release agent containing a phosphate ester represented by the following formula (2) in an amount of 50% by weight or more in the release agent is preferable.

{R _1- (R ₂ O) n} m-P (O)-(OH) ₃ -m (2) (wherein, R ₁ and R ₂ represent an alkyl group having 1 to 20 carbon atoms) , M represents 1 or 2, and n represents a number average of 0 to 100.
Indicates)

The cell of the step-2 is exemplified by a cell composed of two glass plates or two metal plates, a soft sealing material and a clamp, or a continuous cell formed by two stainless steel continuous belts. be able to. The thickness of the cell can be selected so as to obtain a desired resin plate, and generally ranges from about 0.1 to about 30 mm.

The polymerization method in step 3 is a known polymerization method called a so-called cell casting method. The polymerization is hot air,
This can be done by heating the cell with a heat source exemplified by hot water and an infrared heater. The temperature and time of the polymerization may be appropriately selected depending on the type and amount of the polymerization initiator and the composition of the mixture obtained in Step-1, and are generally from 50 to 120 ° C. for 1 to several tens of hours.

The removal of the polymer (resin plate) from the cell in the step-4 may be performed by disassembling (disassembling) the cell.

The methacrylic resin plate for producing sanitary articles of the present invention may be used by laminating with a known resin such as an ABS resin or a urethane resin, if necessary.

[0030]

According to the present invention, it is possible to stably and easily produce a methacrylic resin plate having excellent peel resistance and moldability for producing sanitary articles. Since the resin plate has a low tensile strength at the time of thermoforming and a large elongation at break, it can be easily formed into a deep-drawn sanitary article exemplified by a bathtub or a washbasin.

[0031]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited by these.

1. Tensile test According to JIS K-7113, the distance between marked lines is 15m.
m, using a test piece having the same shape as the JIS No. 2 test piece except that the sample thickness was 5 mm,
, And a tensile test was performed under the conditions of a crosshead speed of 500 mm / min to determine the elongation at break (%).

2. Creep measurement Rheometric Scientific viscoelasticity measuring device (SR-500
0) and the creep index (t
im-η slope value (Pa)). Procedure-1: Cut a 5 mm thick methacrylic resin plate,
Obtain a circular sample of mmФ. Procedure-2: The sample is set on a measuring jig (parallel plate of 25 mmФ) kept at 180 ° C and left for 15 minutes to confirm that the sample has reached 180 ° C. Procedure-3: Rotate the sample in the direction of rotation for 500 seconds.
After applying a stress (σ) of 00 Pa, the stress is removed. Step-4: The creep compliance J (t) (≡γ (t) / σ) is obtained from the time change γ (t) of the strain amount. Procedure-5: A straight line is obtained by plotting the shear viscosity η (t) (the reciprocal of the time derivative of time-J (t)) against time. Step-6: The initial gradient of the straight line is calculated as time-η gradient value (P
a). A methacrylic resin plate having a larger time-η inclination value has a larger force to return to a shape before applying stress, and thus has a lower peel resistance.

3. Stress Relaxation Measurement Using a viscoelasticity measuring device (RDA-2 type) manufactured by Rheometric Co., it was measured according to the following procedure to determine a stress relaxation index. Procedure-1: A resin sample having a size of 5 mm in thickness, 3 mm in width, and 55 mm in length is prepared. Step-2: The sample is set on a chuck-type measuring jig such that the measuring length becomes about 3.8 mm. Step-3: After raising the measurement temperature to 80 ° C, leave it for 10 minutes to confirm that the sample has reached 80 ° C. Step-4: 1% distortion in the rotation direction for the sample is 37
For a minute, the relationship between time and relaxation modulus is determined from the generated stress. Procedure-5: The measurement temperature is changed to 90 ° C. and 95 ° C. in the same manner as above, and the relationship between the time at each temperature and the relaxation modulus is determined. Procedure-6: From the relationship between the time at 80 ° C., 90 ° C., and 95 ° C. and the relaxation modulus, 1 × 10 ⁵ seconds at 80 ° C. using the principle of time-temperature superposition with the reference temperature at 80 ° C. The relationship between the time and relaxation modulus is determined. Step-7: The relaxation modulus G (2) after 1 × 10 ⁵ seconds obtained in this way is divided by the relaxation modulus G (1) after 0.05 seconds to obtain a stress relaxation index G (2). / G (1) was determined.

4. Moldability Evaluation The following procedure evaluated. Procedure-1: A mold capable of forming a rectangular box is set in a vacuum forming apparatus with a built-in slide-type infrared heater. Here, the size of the mold is such that the bottom surface corresponding to the bottom of the box is 280 mm × 280.
mm, the depth corresponding to the side of the box is 70 mm, and the radius of curvature R between the bottom and the side is 5 mm. Step-2: A resin sheet is set on the mold. Procedure-3: After heating the surface of the sheet to 180 ° C, vacuum forming is performed. The sample that could be formed into a box having the desired shape was rated as ○, and the sample that could not be molded was rated as ×.

5. Peeling resistance evaluation Peeling resistance was evaluated by the following procedure. Procedure-1: Length 270mm, width 220mm, thickness 5mm
Attach the methacrylic resin plate to the fixed frame. Step-2: Heat the resin plate with a far infrared heater until the surface temperature of the resin plate reaches 200 ° C. Step-3: The resin plate in a heated state is pushed up and molded. Step-4: After 2 minutes have passed from the point of pushing up, the entire molded product is strongly cooled by a spot cooler for 5 minutes. Step-5: Measure the pushing height from the bottom surface to the inside of the fixed frame with a measure of 0.5 mm unit, and form the molding height (H ₀ )
And Procedure-6: The molded article is immersed in hot water at 90 ° C. for 5 days, and then the molding height (H ₁ ) is measured. Step-7: The push-up molding return rate is calculated from the following equation (3). Push-up molding return rate (%) ≡ (H ₀ −H ₁ ) / H ₀ × 100 (3) Step-8: The above-mentioned push-up molding return rate of 30% or less is regarded as having excellent peeling resistance (marked with “○”). If it is greater than 30%, the peel resistance is poor (marked with x).

Example 1 (a) 25% by weight of a methyl methacrylate polymer having a viscosity average molecular weight of 130,000 obtained by suspension polymerization of 95.0% by weight of methyl methacrylate and 5.0% by weight of methyl acrylate. Parts, (b) 70.5 parts by weight of methyl methacrylate monomer, (c) 4.5 parts by weight of 2-ethylhexyl acrylate, and (d) 0.18 parts by weight of neopentyl glycol dimethacrylate (polyfunctional monomer) And (e) 0.06 parts by weight of lauryl mercaptan (serial transfer agent);
(F) 0.1 weight of 2,2 ′ azobisisobutyronitrile (polymerization initiator) and (g) 0.01 weight of a release agent called Phosphanol RS710 (trade name) manufactured by Toho Chemical Co., Ltd. Parts were mixed to obtain a mixture. Here, (b) methyl methacrylate monomer and (c) 2-ethylhexyl acrylate correspond to the “methyl methacrylate monomer” of the present invention. The molar ratio of the polyfunctional monomer to lauryl mercaptan was 2.5. After the mixture was degassed, it was poured into a 5 mm thick cell composed of two glass plates and a gasket made of vinyl chloride resin. After the mixture injected into the cell was polymerized at 65 ° C. for 4 hours and further at 120 ° C. for 1 hour, the polymer (resin plate) was taken out of the cell to obtain a methacrylic resin plate. Table 2 shows the test results of the obtained resin plates.

Examples 2, 3, 5 to 8 and Comparative Examples 1 and 2 (a) Type and amount of methyl methacrylate polymer, (b)
Example 1 was repeated except that the amount of the methyl methacrylate monomer, (c) the amount of 2-ethylhexyl acrylate, (d) the amount of the polyfunctional monomer, and (e) the amount of the serial transfer agent were as shown in Table 1. The same was done. The evaluation results are shown in Table 2 for Example 2, and Table 3 for Examples 3, 5 to 8 and Comparative Examples 1 and 2.

Example 4 (c) 2-ethylhexyl acrylate was replaced with butyl acrylate, and (d) 0.18 parts by weight of neopentyl glycol dimethacrylate (a polyfunctional monomer) was replaced with 0.10 parts by weight of ethylene glycol dimethacrylate. Except having changed, it carried out similarly to Example 1. Table 3 shows the evaluation results.

[0040]

[Table 1]

[0041]

[Table 2]

[0042]

[Table 3]

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Claims (10)

[Claims] 1. A methacrylic resin plate for producing sanitary articles having a breaking elongation of 700% or more and a creep index of 1 × 10 ⁶ Pa or less. 2. The elongation at break is 800% or more.
A methacrylic resin plate for manufacturing sanitary articles according to the above. 3. The methacrylic resin plate according to claim 1, wherein the stress relaxation index is 0.07 or less. 4. The methacrylic resin plate for producing sanitary articles according to claim 2, wherein the stress relaxation index is 0.07 or less. 5. The methacrylic resin plate for producing sanitary articles according to claim 1, wherein the stress relaxation index is 0.035 or less. 6. The methacrylic resin plate for producing sanitary articles according to claim 2, wherein the stress relaxation index is 0.035 or less. 7. A method for producing a methacrylic resin plate for producing sanitary articles, comprising the following steps. Step-1: 5-35 parts by weight of a methyl methacrylate-based polymer having a viscosity average molecular weight of 50,000 to 300,000, 65 to 95 parts by weight of a methyl methacrylate-based monomer, and polyfunctionality copolymerizable with the methyl methacrylate-based monomer Monomer 0.1-0.5
Parts by weight, and 80% by weight or more of a chain transfer agent comprising an alkyl mercaptan, and a molar ratio of the alkyl mercaptan to the polyfunctional monomer in the chain transfer agent is 1.5 to 3.5. Step of mixing a chain transfer agent with 0.01 to 0.30 parts by weight to obtain a mixture (the total amount of the methyl methacrylate-based polymer and the methyl methacrylate-based monomer is 100 parts by weight, and a polyfunctional monomer and (The ratio of each of the chain transfer agents is based on 100 parts by weight.) Step-2: a step of injecting the mixture into a cell Step-3: a step of polymerizing the mixture injected into a cell Step-4: Step of removing from cell 8. The methyl methacrylate-based polymer is a copolymer comprising a structural unit derived from a methyl methacrylate monomer and a structural unit derived from an acrylate ester, wherein the polymer is derived from a methyl methacrylate monomer. When the total amount of the structural units derived from the acrylate and the structural units derived from the acrylate is 100% by weight, the ratio of the structural units derived from the acrylate in the copolymer is 0.5% by weight. % Of the methacrylic resin plate for producing sanitary goods according to claim 7. 9. A methyl methacrylate monomer of 65 to 95.
The method according to claim 7, wherein 0.5 to 15 parts by weight of the methacrylic acid ester is an acrylate ester. 10. The method according to claim 7, wherein the polyfunctional monomer is neopentyl glycol diacrylate or neopentyl glycol dimethacrylate.