JP6542501B2 - Method for producing methacrylic resin, methacrylic resin, and molded body - Google Patents

Description

  The present invention relates to a method for producing a methacrylic resin, a methacrylic resin, and a molded article.

BACKGROUND ART Methacrylic resins represented by polymethyl methacrylate (PMMA) are widely used in the fields of optical materials, lenses, household goods, OA equipment, lighting equipment, members for vehicles, and the like because of their high transparency.
In particular, in recent years, the use for optical materials such as a light guide plate and a film for liquid crystal display has been advanced, and it is also developed to applications assuming use under high temperature, and higher heat resistance and optical characteristics are required. .

Conventionally, as a method of improving the heat resistance of PMMA, a method of introducing a maleimide-based monomer into a polymerization system of PMMA has been proposed (see, for example, Patent Document 1 and Patent Document 2).
In general, since maleimide monomers are often solid at room temperature, when the polymerization of PMMA is carried out by bulk polymerization or suspension polymerization, maleimide monomers are monomers other than the maleimide monomers. After dissolution in seeds, the solution is often subjected to a polymerization system. However, there is a problem that the productivity is inferior because it takes a long time to dissolve the maleimide monomer in the monomer species.
As a method of introducing a maleimide-based monomer into a polymerization system of PMMA without dissolving it, a method of supplying a maleimide-based monomer as an aqueous dispersion to the polymerization system has been proposed (see, for example, Patent Document 3). ). There is also disclosed a method in which a maleimide-based monomer is directly charged into a reaction tank and then finely dispersed in the reaction tank and then subjected to a reaction (see, for example, Patent Document 4).

Japanese Patent Application Laid-Open No. 61-252211 Japanese Patent Application Laid-Open No. 63-304013 Japanese Patent Application Laid-Open No. 62-68805 JP 01-153707 A

However, in the manufacturing methods described in Patent Documents 1 and 2, the maleimide monomer is dissolved in another monomer type to obtain a solution, and the solution is supplied to the reaction tank to form a maleimide into a polymerization system. In particular, maleimide-based monomers are difficult to dissolve in other monomer species in low temperature environments such as winter, because the system monomers are introduced, and the solubility is further reduced due to the heat absorption at the time of dissolution. The problem is that there is room for improvement in terms of productivity.
Moreover, in the manufacturing method described in Patent Document 3, the maleimide-based monomer is finely dispersed in water and continuously fed as a maleimide slurry, but in order to improve the dispersibility, the maleimide-based monomer is Since the particle diameter of the particles is as small as possible and the surface area of the particles is increased, the contact area with water is increased, which makes it easy to cause the hydrolysis of maleimide, and the polymerization stability is generated by the generated acidic component. In addition, there is a problem that the desired characteristics may not be obtained.
Moreover, in the manufacturing method described in Patent Document 4, after supplying the powder of maleimide to the reaction tank, the maleimide is finely dispersed as a solid solution at high temperature and then subjected to the reaction. Hydrolysis is likely to occur and the polymerization stability may be reduced.
In view of the problems of the prior art described above, PMMA having high productivity and capable of retaining high characteristics, in which the contact time between water and particles of maleimide monomer is reduced in order to suppress hydrolysis of maleimide. There is a need for a process for the polymerization of
Therefore, the present invention provides a method for efficiently producing a methacrylic resin having high heat resistance, excellent in color tone and transparency, and excellent in moisture and heat resistance while maintaining high productivity and polymerization stability. To be an issue.

The present inventors have completed the present invention as a result of intensive studies to solve the problems of the prior art described above.
That is, the present invention is as follows.

[1]
Methacrylate ester monomer (A): 50 to 99% by mass,
1 to 30% by mass of maleimide monomer (B),
And other vinyl monomer (C): having a polymerization step of copolymerizing 0 to 20% by mass in a reaction vessel,
The manufacturing method of methacrylic resin which satisfy | fills the conditions of following (1)-(5).
(1) The maleimide monomer (B) is solid at 25 ° C.
(2) The maleimide monomer (B) is supplied to the reaction tank in a solid state.
(3) The content of the particle diameter component of 0.15 mm or less of the maleimide monomer (B) is
It is 3 % by mass or less.
(4) The temperature in the reaction tank at the time of supplying the maleimide monomer (B) in a solid state to the reaction tank is 0 ° C. or more and 80 ° C. or less.
(5) The temperature in the reaction tank when supplying a polymerization monomer other than the maleimide monomer (B) to the reaction tank is 0 ° C. or more and 80 ° C. or less.
[2]
The method for producing a methacrylic resin according to the above [1], wherein the maleimide monomer (B) is at least one selected from the group consisting of N-phenyl maleimide and N-cyclohexyl maleimide.
[3]
The method for producing a methacrylic resin according to the above [1] or [2], wherein the polymerization step is carried out by a suspension polymerization method.
[4]
The temperature in the reaction vessel at the time of supplying a monomer component other than the maleimide monomer (B) to the reaction vessel is 10 ° C. or more lower than the melting point of the maleimide monomer (B) , Said [1
] The manufacturing method of methacrylic resin as described in any one of [3].
[5]
The method for producing a methacrylic resin according to any one of the above [1] to [4], wherein the content of the particle diameter component of 9.5 mm or more of the maleimide monomer (B) is 10% by mass or less .
[6]
The method for producing a methacrylic resin according to any one of the above [1] to [5], wherein the average particle diameter of the maleimide monomer (B) is 0.2 mm or more and 9 mm or less.
[7]
In the polymerization step, the polymerization initiator is supplied to the reaction vessel together with the methacrylic acid ester-based monomer (A) and the other vinyl-based monomer (C).
6] The manufacturing method of methacrylic resin as described in any one of 6).

  According to the present invention, it is possible to provide a method for efficiently producing a methacrylic resin having high heat resistance and excellent in color tone, transparency and moisture heat resistance while maintaining high productivity and polymerization stability. it can.

Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail, but the present invention is not limited to the following description, and within the scope of the gist thereof Various modifications are possible.
In addition, below, the thing of the monomer component before superposition | polymerization is called "-monomer", and a "monomer" may be abbreviate | omitted. Moreover, the thing of the structural unit which comprises a polymer is called "-monomer unit."

[Method for producing methacrylic resin]
In the method for producing the methacrylic resin of the present embodiment,
Methacrylate ester monomer (A): 50 to 99% by mass,
1 to 30% by mass of maleimide monomer (B),
And the polymerization step of copolymerizing 0 to 20% by mass of the other vinyl monomer (C) copolymerizable with the (A) and (B) in the reaction vessel,
It is assumed that the following conditions (1) to (3) are satisfied.
(1) The maleimide monomer (B) is solid at 25 ° C.
(2) The maleimide monomer (B) is supplied to the reaction tank in a solid state.
(3) The content of the particle diameter component of 0.15 mm or less in the maleimide monomer (B) is 10% by mass or less.
Hereinafter, the method for producing the methacrylic resin of the present embodiment will be described in detail.

In the production method of the present embodiment, 50 to 99% by mass of the methacrylic acid ester monomer (A), 1 to 30% by mass of the maleimide monomer (B), and the above (A) and (B). A methacrylic resin is manufactured using a monomer component by the mass ratio of 0-20 mass% of other monomers (C) which can be polymerized.
The details of each monomer component are described below.

(Methacrylic acid ester monomer (A))
As a methacrylic acid ester monomer (A) (Hereafter, it may describe as (A) component and (A).), The monomer shown by following General formula (1) is used suitably.

In the general formula (1), R ₁ represents a methyl group. R ₂ represents a group having 1 to 12 carbon atoms, preferably a hydrocarbon group having 1 to 12 carbon atoms, and may have a hydroxyl group on carbon.

Examples of the methacrylic acid ester-based monomer represented by the general formula (1) include, but are not limited to, butyl methacrylate, ethyl methacrylate, methyl methacrylate, propyl methacrylate and isopropyl methacrylate, for example. They include cyclohexyl methacrylate, phenyl methacrylate, methacrylate (2-ethylhexyl), methacrylate (t-butylcyclohexyl), benzyl methacrylate, methacrylate (2,2,2-trifluoroethyl), etc. From the viewpoint of length and the like, methyl methacrylate is preferred.
The methacrylic acid ester monomers may be used alone or in combination of two or more.
The methacrylic acid ester-based monomer (A) is 50 from the viewpoint of the heat resistance imparting effect of the maleimide-based monomer (B) described later among all the monomer components used in the method for producing a methacrylic resin according to the present embodiment. It is contained at about 99% by mass, preferably 60 to 95% by mass, more preferably 70 to 95% by mass, still more preferably 75 to 95% by mass, and still more preferably 78 to 90% by mass.

(Maleimide monomer (B))
In the method for producing a methacrylic resin according to this embodiment, the maleimide monomer (B) (hereinafter, referred to as component (B), component (B) may be described from the viewpoint of improving the heat resistance of the methacrylic resin. The maleimide monomer (B) is solid at 25 ° C.
As the maleimide monomer (B), a monomer represented by the following general formula (2) is suitably used.

R ₃ in the general formula (2) is selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, and an aryl group having 6 to 12 carbon atoms And may have a substituent on the carbon atom.

Examples of the maleimide monomer (B) include, but are not limited to, for example, maleimide, N-methyl maleimide, N-ethyl maleimide, N-cyclohexyl maleimide, N-phenyl maleimide, N- (o- (o-) Chlorophenyl) maleimide, N- (m-chlorophenyl) maleimide, N- (p- chlorophenyl) maleimide etc. are mentioned.
Preferably, N-cyclohexyl maleimide, N-phenyl maleimide, N- (o- chlorophenyl) maleimide, N- (m- chlorophenyl) maleimide, N- (p- chlorophenyl) maleimide are mentioned. From the viewpoint of availability and heat resistance, N-cyclohexylmaleimide and N-phenylmaleimide are more preferable, and N-phenylmaleimide is more preferable.
The maleimide-based monomer (B) described above may be used alone or in combination of two or more.

The method for producing a methacrylic resin according to this embodiment is characterized in that the maleimide monomer (B) is supplied to the reaction tank in a solid state.
By supplying the maleimide monomer (B) in a solid state to the reaction tank, the production time of the methacrylic resin can be shortened while maintaining good polymerization stability.

The average particle diameter of the maleimide monomer (B) is preferably 0.2 mm to 9 mm from the viewpoint of handling workability and polymerization stability at the time of suspension polymerization of the methacrylic resin. More preferably, they are 0.5 mm-8 mm, More preferably, they are 1 mm-5 mm.
The measuring method of the average particle diameter of a maleimide-type monomer (B) is shown below.
For example, a sieve based on JIS-Z8801, JTS-200-45-16 (open 9.5 mm) manufactured by Tokyo Screen, JTS-200-45-19 (open 5.6 mm), 21 (open 4.0 mm) , 23 (opening 2.8 mm), 25 (opening 2.0 mm), 32 (opening 0.6 mm), 38 (opening 150 μm), 61 (receiving pan), and using the screening tester TSK B- The particle diameter of 50% by mass can be measured and determined using the measurement value of the average particle diameter when sieving is performed for 10 minutes with the vibration force MAX using 1.
In the method for producing a methacrylic resin according to this embodiment, as described later, the content of the particle diameter component of 0.15 mm or less of the maleimide monomer (B) is 10% by mass or less. The component content of 0.15 mm or less can be determined by dividing the mass of the maleimide monomer (B) remaining in the pan by the mass of the entire sample used for the measurement.

In addition, when the maleimide monomer (B) is brought into contact with water, it may open to form a maleamic acid. This causes problems such as a decrease in polymerization stability and coloring. Therefore, it is better that the number of fine particles having a large specific surface area is small.
From this viewpoint, in the method for producing a methacrylic resin according to the present embodiment, as described above, specifically, the content of the particle diameter component of 0.15 mm or less is 10% by mass or less. Preferably it is 5 mass% or less, More preferably, it is 3 mass% or less.

  Furthermore, in the polymerization step of copolymerizing the polymerization monomer component constituting the methacrylic resin, in order to enhance the polymerization stability, maleimide is introduced after charging other monomer species other than the component (B) to the reaction tank. When supplying the monomer (B) to the reaction tank, or after supplying the maleimide monomer (B) to the reaction tank, and charging other monomer species other than the component (B), the maleimide It is preferable that the monomer (B) dissolves quickly in the other monomer species. From the viewpoint of solubility of the maleimide-based monomer (B) in other monomer species, the content of components of 9.5 mm or more contained in the maleimide-based monomer (B) is 10% by mass or less preferable. More preferably, it is 8 mass% or less, more preferably 5 mass% or less.

Moreover, it is preferable that the acid value of a maleimide-type monomer (B) is 2.0 or less from a viewpoint of prevention of metal corrosion and the polymerization stability in the case of performing aqueous suspension polymerization. More preferably, it is 1.5 or less, more preferably 1.0 or less.
The acid value of the maleimide monomer (B) can be measured by the method of JIS-K-2501-2003.
From the viewpoint of the heat resistance of the methacrylic resin, the maleimide monomer (B) is contained in an amount of 1 to 30% by mass in all the monomers used in the method for producing the methacrylic resin of the present embodiment, Preferably, it is contained in an amount of 1 to 25% by mass, more preferably 3 to 25% by mass, still more preferably 5 to 25% by mass, and still more preferably 5 to 20% by mass.

(Other vinyl monomers (C) copolymerizable with (A) and (B))
In the method for producing a methacrylic resin according to the present embodiment, other vinyl monomers (C) copolymerizable with the (A) component and the (B) component as long as the effects of the present invention are not impaired (C) may be described as component (C).
Although the content in the case of using the other vinyl-type monomer (C) which can be copolymerized into the said (A) component and (B) component differs in the purpose used depending on the vinyl-type monomer to be used, for example, From the viewpoint of the effect of reducing the amount of residual monomers and imparting of solvent resistance, it is 20% by mass or less, preferably 18% by mass or less, more preferably 15% by mass or less, still more preferably 12% by mass or less. Still more preferably, it is 10% by mass or less.
Further, the content of the component (C) is 0.1% by mass or more in all monomers from the viewpoint of appropriately imparting the required characteristics such as chemical resistance, thermal stability, reactivity, etc. in addition to the desired characteristics. Is preferably 0.5% by mass or more, and more preferably 1% by mass or more.

  Examples of the component (C) include, but are not limited to, aromatic vinyl monomers represented by the following general formula (3) and acrylic acids represented by the general formula (4). Ester monomers, vinyl cyanide compounds such as acrylonitrile and methacrylonitrile; amides such as acrylamide and methacrylamide; ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) Products obtained by esterifying both terminal hydroxyl groups of ethylene glycol or oligomers thereof such as acrylate and tetraethylene glycol di (meth) acrylate with acrylic acid or methacrylic acid; 2 such as neopentyl glycol di (meth) acrylate or di (meth) acrylate The hydroxyl group of this alcohol is acrylic acid or Those that have been esterified with methacrylic acid; trimethylolpropane, those polyhydric alcohol derivatives such as pentaerythritol was esterified with acrylic acid or methacrylic acid; polyfunctional monomers such as divinylbenzene, and the like.

In the general formula (3), R ₄ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and may have a hydroxyl group on the alkyl group.
n represents an integer of 0 to 5;
R ₅ is a group consisting of a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 1 to 8 carbon atoms, and an aryl group having 1 to 8 carbon atoms And all of R ₅ may be the same group or different groups.
In addition, R ₅ may form a ring structure.

In the general formula (4), R ₆ is a hydrogen atom, R ₇ is an alkyl group having 1 to 18 carbon atoms.

  The component (C) can be appropriately used according to the required properties, but when properties such as heat stability, flowability, mechanical properties, chemical resistance and the like are particularly required, an aromatic vinyl group may be used. A monomer (C-1), an acrylic acid ester monomer (C-2), and a vinyl cyanide monomer (C-3) can be suitably selected and used suitably.

<Aromatic vinyl monomer (C-1)>
Examples of the aromatic vinyl monomer include, but are not limited to, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, and 2,5, for example. Dimethylstyrene, 3,4-dimethylstyrene, 3,5-dimethylstyrene, p-ethylstyrene, m-ethylstyrene, о-ethylstyrene, p-tert-butylstyrene, 1-vinylnaphthalene, 2-vinylnaphthalene, 1,1-Diphenylethylene, Isopropenylbenzene (α-methylstyrene), Isopropenyltoluene, Isopropenylethylbenzene, Isopropenylpropylbenzene, Isopropenylbutylbenzene, Isopropenylpentylbenzene, Isopropenylhexylbenzene, Isopropenyloctylbenzene, etc. Can be mentioned.
These are suitably selected according to the characteristic requested | required in the methacrylic resin made into the end finally. Among the above, styrene and isopropenylbenzene are preferable, and styrene is more preferable from the viewpoint of imparting of fluidity, reduction of unreacted monomers by improvement of polymerization conversion ratio, and the like.
Blending ratio (mass ratio) of the aromatic vinyl monomer unit (C-1) and the maleimide monomer (B) when the aromatic vinyl monomer unit (C-1) is used It is preferable to satisfy the following expression from the viewpoint of processing flowability at the time of molding processing, a silver streaks reducing effect by reducing residual monomers, and the like.
0.3 ≦ (C−1) / (B) ≦ 5
From the viewpoint of maintaining good color tone and heat resistance, the upper limit value is preferably 5 or less, more preferably 3 or less, and still more preferably 1 or less.
Moreover, it is preferable that it is 0.3 or more from a viewpoint of reducing the residual maleimide-type monomer (B), More preferably, it is 0.35 or more, More preferably, it is 0.4 or more.
The above-mentioned aromatic vinyl monomer (C-1) may be used alone or in combination of two or more.

<Acrylate ester monomer (C-2)>
Examples of the acrylic ester-based monomer include, as described above, a compound in which the substituent R ₇ is an alkyl group having 1 to 18 carbon atoms in the general formula (4), and among them, the compound of the present embodiment In the methacrylic resin obtained by the production method, from the viewpoint of enhancing the weather resistance, heat resistance, flowability and thermal stability, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, sec acrylic acid -Butyl, 2-ethylhexyl acrylate and the like are preferable, and methyl acrylate, ethyl acrylate and n-butyl acrylate are more preferable, and methyl acrylate is more preferable from the viewpoint of availability.
The content in the case of using the acrylic acid ester monomer (C-2) is (A), (A), from the viewpoint of retention of the heat resistance imparting effect by the maleimide monomer (B) and imparting of thermal stability. When the sum total of B) and (C) component is 100 mass parts, it is preferable that it is 5 mass parts or less, More preferably, it is 3 mass parts or less.
As the acrylic acid ester monomer (C-2), one type may be used alone, or two or more types may be used in combination.

<Cyanide vinyl compound (C-3)>
The vinyl cyanide compound is not particularly limited, and examples thereof include acrylonitrile, methacrylonitrile, vinylidene cyanide and the like, among which acrylonitrile is preferably used.
The content in the case of using the vinyl cyanide compound (C-3) is (A) and (B) from the viewpoint of retention of the heat resistance imparting effect by the maleimide monomer (B) and the addition of the solvent resistance. When the total of components (C) is 100 parts by mass, it is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, still more preferably 12 parts by mass or less, particularly preferably 10 parts by mass or less It is.

(Manufacturing process of methacrylic resin)
Next, although the method to manufacture methacrylic resin using the monomer component mentioned above is demonstrated, the manufacturing method of methacrylic resin of this embodiment is not limited to the method shown below.
The maleimide monomer (B) used in the polymerization step in the method for producing a methacrylic resin according to this embodiment is solid at 25 ° C., and is charged into a reaction tank for carrying out the polymerization step in the solid state without being dissolved, Dissolved in the monomers of the above and subjected to the reaction. The maleimide-based monomer (B) is dissolved in the reaction tank with another monomer such as the methacrylic acid ester-based monomer (A).
In the prior art, the maleimide monomer (B), which is a solid raw material, is dissolved in advance in a solvent type in which the maleimide monomer (B) is copolymerized therewith, or in the solvent in which the maleimide monomer (B) can be dissolved. It was put into the tank and made to react.
However, the solubility of the solid maleimide monomer (B) in the copolymerized methacrylic acid ester monomer (A) is low, and if it is a small amount, it does not have a long time to dissolve, but it produces a large amount When it is necessary, considerable time is required to dissolve the maleimide monomer (B), and a large amount of energy is required due to stirring and dissolution for a long time. In addition, by setting the temperature higher than normal temperature, the solubility is improved and the dissolution time is shortened, but when the reactive monomer is placed at a high temperature, it is polymerized during the dissolution, and the inside of the dissolution tank, Since it becomes easy to solidify by transfer piping etc. from a dissolution tank to a reaction tank, continuous productivity falls and is unpreferable.
In the present embodiment, dissolution for dissolving the maleimide-based monomer (B) is performed by supplying the solid maleimide-based monomer (B) in the solid state directly to the reaction tank without dissolving it. The time can be shortened, and the methacrylic resin can be stably produced.

The methacrylic resin comprises a methacrylic acid ester monomer (A), a maleimide monomer (B), and other vinyl monomers copolymerizable to (A) and (B) as described above. It can be produced by solution polymerization, suspension polymerization, bulk polymerization, precipitation polymerization, and emulsion polymerization using the body (C). Preferably, a solution polymerization method, a suspension polymerization method and a bulk polymerization method are used, more preferably a solution polymerization method and a suspension polymerization method, and still more preferably a suspension polymerization method.
When the polymerization step is carried out by the suspension polymerization method, if the solid raw material is introduced into the reaction tank, if the surface area of the solid raw material is large, hydrolysis occurs by contact with water, even if the polymerization proceeds. The polymerization state may become unstable, and may solidify at the end of polymerization, which may make stable production difficult. In addition, when exposed to high temperature and high humidity conditions, the color tone may be deteriorated.
In the method for producing the methacrylic resin of the present embodiment, in view of the stability of the polymerization state, the content of the particle diameter component of 0.15 mm or less contained in the maleimide monomer (B) is 10% by mass or less did. As a result, even if the solid maleimide monomer (B) is not dissolved but is charged into the reaction tank and reacted, the maleimide powder having a large surface area is hydrolyzed by contact with water, thereby causing ring opening. Can be effectively prevented from becoming unstable and the polymerization system is destabilized, the polymerization time can be reduced while maintaining the polymerization stability, and stable production can be achieved. The formation of by-products such as amines derived from the hydrolysis of the monomer (B) is also suppressed.

<Production Method by Suspension Polymerization>
Hereinafter, in the method for producing the methacrylic resin of the present embodiment, a suspension polymerization method which can be particularly suitably used will be described as an example, but the method is not limited to the suspension polymerization method.
In the case of production by suspension polymerization such as organic suspension polymerization method or inorganic suspension polymerization method, a particulate methacrylic resin can be obtained through a polymerization step using a stirring device described later, a washing step, a dehydration step, and a drying step. Can be manufactured. Usually, an aqueous suspension polymerization method using water as a medium is suitably used.

<Polymerization process>
In the polymerization step, the above-mentioned methacrylic acid ester monomer (A), maleimide monomer (B), and, if necessary, other vinyl monomers (C) in a predetermined reaction tank, Copolymerize.
The predetermined reaction tank is not limited to the following, but for example, a container with a stirrer can be used, that is, a stirrer can be used, and a monomer, a suspending agent, and the like appropriately used as raw materials in the stirrer. The polymerization is carried out by supplying a polymerization initiator, a chain transfer agent and other additives as required, to obtain a slurry of methacrylic resin.
In polymerization, water, a suspending agent, a solid maleimide monomer (B), a methacrylic acid ester monomer (A), and other vinyl monomers (C) which can be polymerized are contained in the reaction tank. And additives such as a polymerization initiator are introduced into the reaction tank, but the order of introduction is not particularly limited as long as the effects of the present invention can be obtained. It is preferable to supply the polymerization initiator together with the methacrylic acid ester monomer (A) and the other vinyl monomer (C) from the viewpoint of ease of handling.

As an example of the order of charging the solid maleimide monomer (B) into the reaction tank, (I) a method of charging the maleimide monomer (B) after introducing water, (II) a unit of maleimide monomer in advance Body (B) is introduced into the reaction tank and then water is charged, (III) water, methacrylic acid ester monomer (A), and the other vinyl monomers (C) that can be added and polymerized. After adding an additive such as a polymerization initiator, a method of adding a maleimide monomer (B), and the like can be mentioned.
The temperature in the reaction tank at the time of charging the maleimide monomer (B) is lower by 10 ° C. or more than the melting point of the maleimide monomer (B) from the viewpoint of suppressing the ring opening at the time of contact with water. Is preferably 20.degree. C. or more, more preferably 30.degree. C. or more. Specifically, the temperature is preferably 80 ° C. or less. When water is previously introduced into the reaction tank, it is preferably 70 ° C. or less, more preferably less than 60 ° C., from the viewpoint of hydrolysis suppression of the maleimide monomer (B). It is preferable that the preferable minimum temperature at the time of introduction | transduction is a temperature which the water used for use does not coagulate, and it is preferable that it is 0 degreeC or more. More preferably, it is 5 ° C. or more, more preferably 10 ° C. or more.

In addition, when the maleimide monomer (B) is introduced before adding the other monomers, the stirring time from the introduction of the maleimide monomer (B) to the addition of the other monomers is as follows: Although not particularly limited, it is preferably 1 to 180 minutes, more preferably 1 to 150 minutes, still more preferably 5 to 150 minutes, still more preferably 5 in consideration of work efficiency and polymerization stability. It is -120 minutes, more preferably 10-90 minutes.
When water is charged after maleimide-based monomer (B) is charged, or when maleimide-based monomer (B) is charged after water is added, the temperature of the charged water is maleimide hydrolysis suppression It is preferable that it is temperature lower 10 degreeC or more than melting | fusing point of a maleimide-type monomer (B) from a viewpoint of these. That is, it is preferable that it is the temperature conditions which the input powder does not fuse | melt. The methacrylate ester (A) to be used is preferably 80 ° C. or less, more preferably 75 ° C. or less, still more preferably 70 ° C., still more preferably less than 60 ° C. from the viewpoint of volatilization suppression. It is preferable that the preferable minimum temperature at the time of introduction | transduction is a temperature which the water used for use does not coagulate, and it is preferable that it is 0 degreeC or more. More preferably, it is 5 ° C. or more, more preferably 10 ° C. or more, and still more preferably 20 ° C. or more. The stirring time until addition of the other monomer after the addition of water is not particularly limited, but it is preferably 1 to 180 minutes, more preferably 1 to 150 minutes in consideration of the working efficiency. More preferably, it is 5 to 150 minutes, still more preferably 5 to 120 minutes, still more preferably 10 to 90 minutes.
The pH of water used in the polymerization step of the methacrylic resin is not particularly limited, but is preferably in the range of pH 4 to 11 from the viewpoint of suspension stability and hydrolysis resistance. More preferably, it is pH 4-9, More preferably, it is pH 4.5-8.

As a reaction vessel used in a polymerization process for obtaining a methacrylic resin by suspension polymerization, specifically, as a stirring device which is a container equipped with a stirrer, an inclined paddle blade, a flat paddle blade, a propeller blade, an anchor inside Stirring with stirring blades such as wings, Faudler wings (swept wings), turbine wings, bull margin wings, max blend wings, full zone wings, ribbon wings, Ikari wings, super mix wings, intermig wings, special wings, axial wings The apparatus includes a known stirring apparatus such as a stirring apparatus having a shovel blade inside, a stirring apparatus having a chopper blade inside, and a stirring apparatus having a rotating disk such as a disk type, a notch disk type or a screw type inside.
The stirring speed at the time of polymerization depends on the type of stirring apparatus used, the stirring efficiency of the stirring blade, the capacity of the polymerization tank, etc., but an appropriate particle size can be obtained, and the component containing particle size of less than 0.15 mm In view of the fact that the amount can be reduced, the polymerization stability, etc., it is preferable to be about 1 to 500 revolutions / minute.

The temperature of the water in the reaction tank when adding the raw material mixture of the copolymer other than the maleimide monomer (B) constituting the methacrylic resin may be in the range in which the effect of the present invention can be exhibited, It is preferable that the temperature is 0 ° C. or more and the boiling point or less of each raw material to be used. Moreover, it is preferable that it is temperature lower 20 degreeC or more than melting | fusing point of a maleimide-type monomer (B) from a viewpoint of hydrolysis suppression of a maleimide-type monomer (B). More preferably, the temperature is 25 ° C. or more lower than the melting point of the maleimide monomer (B), more preferably 30 ° C. or more lower than the melting point of the maleimide monomer (B).
Specifically, the temperature is preferably 80 ° C. or less, more preferably 70 ° C. or less, and even more preferably less than 60 ° C. It is preferable that it is a temperature which the water used for use does not coagulate | solidify at the time of injection | throwing-in, and it is more preferable that it is 0 degreeC or more. More preferably, it is 5 ° C. or more, and even more preferably 10 ° C. or more.

The polymerization temperature in the suspension polymerization step is preferably 40 ° C. or more and 90 ° C. or less in consideration of the productivity and the amount of aggregates formed. The temperature is more preferably 50 ° C. or more and 85 ° C. or less, still more preferably 60 ° C. or more and 85 ° C. or less, and still more preferably 65 ° C. or more and 83 ° C. or less.
When manufacturing by suspension polymerization, the time (polymerization time) from the addition of the monomer component containing the methacrylic acid ester monomer (A) to the heat generation peak (polymerization time) effectively suppresses heat generation during polymerization. From the viewpoint of enhancing the polymerization stability, it is preferably 30 minutes or more and 240 minutes or less. More preferably, it is 45 minutes or more and 210 minutes or less, more preferably 60 minutes or more and 210 minutes or less, still more preferably 60 minutes or more and 180 minutes or less, and still more preferably 90 minutes or more and 180 minutes or less.
By selecting the polymerization time within the above range, the maleimide monomer (B) is dissolved in the monomer component containing the methacrylic acid ester monomer (A) while the polymerization rate does not exceed 20%. It is preferable because it can be dispersed in it.

Further, from the viewpoint of reducing the amount of residual monomers, it is preferable to raise the temperature to a temperature higher than the polymerization temperature after the above-mentioned polymerization step and to hold for a certain period of time. The temperature for holding is preferably a temperature higher than the polymerization temperature because it can increase the degree of polymerization, and it is preferable to raise the temperature by 5 ° C. or more from the polymerization temperature. When raising temperature, it is preferable that it is below the glass transition temperature of methacrylic resin obtained from a viewpoint of preventing aggregation of the polymer obtained. Specifically, it is 120 ° C. or less, preferably 100 ° C. or less, more preferably 80 ° C. to 100 ° C., still more preferably 85 ° C. to 100 ° C., still more preferably 88 ° C. to 100 ° C., further more Preferably it is 90 degreeC or more and 100 degrees C or less.
The time for maintaining the temperature after the temperature rise is preferably 15 minutes or more and 360 minutes or less, more preferably 30 minutes or more and 240 minutes or less, still more preferably 30 minutes or more and 180 minutes, in consideration of the reduction efficiency of the residual monomer. Hereinafter, more preferably, it is 30 minutes or more and 150 minutes or less. If it is the said range, it is possible to reduce the amount of residual monomers effectively.
By conducting polymerization in accordance with the polymerization temperature and the holding time described above, it is possible to produce particles of a methacrylic resin having a small amount of residual monomers and having a small angle of repose after passing through the drying step described later. .

Cleaning process
The slurry of the methacrylic resin obtained through the above-mentioned polymerization step is preferably subjected to operations such as acid washing, water washing, alkali washing and the like for removing the suspending agent.
The number of times of these washing operations may be selected from the optimum number from the work efficiency and the removal efficiency of the suspending agent, and may be repeated once or plural times.
The temperature for washing may be selected from the optimum temperature in consideration of the removal efficiency of the suspending agent, the degree of coloring of the obtained copolymer, and the like, and is preferably 20 to 100 ° C. More preferably, it is 30-95 degreeC, More preferably, it is 40-95 degreeC.
The washing time per wash is preferably 10 to 180 minutes, more preferably 20 to 150 minutes, from the viewpoint of washing efficiency, repose angle reduction effect, and process simplicity.
The pH of the washing solution used in washing may be in the range in which the suspension can be removed, but is preferably pH 1-12. The pH in the case of acid washing is preferably from 1 to 5 and more preferably from 1.2 to 4 from the viewpoint of the removal efficiency of the suspending agent and the color tone of the obtained copolymer. The acid used at that time is not particularly limited as long as it is capable of removing the suspending agent, and conventionally known inorganic acids and organic acids can be used. As an example of the acid suitably used, hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, oxalic acid etc. are mentioned as an inorganic acid, You may use it as the diluted solution each diluted with water etc. As an organic acid, what has a carboxyl group, a sulfo group, a hydroxyl group, a thiol group, and an enol is mentioned. In view of the effect of removing the suspending agent and the color tone of the obtained resin, more preferred are nitric acid, sulfuric acid, and an organic acid having a carboxyl group.
After the acid washing, it is preferable to further perform water washing and alkali washing from the viewpoint of the color tone of the obtained polymer and the reduction of the repose angle.
The pH of the alkaline solution in the case of alkaline cleaning is preferably pH 7.1 to 12, more preferably pH 7.5 to 11, and still more preferably 7.5 to 10.5.
As the alkaline component used for the alkaline cleaning, tetraalkyl ammonium hydroxide, alkali metal hydroxide, alkaline earth metal hydroxide and the like are suitably used. More preferably, they are alkali metal hydroxides and alkaline earth metal hydroxides, still more preferably lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, magnesium hydroxide, hydroxides Calcium and barium hydroxide are more preferably lithium hydroxide, sodium hydroxide, potassium hydroxide, magnesium hydroxide and calcium hydroxide, and still more preferably sodium hydroxide and potassium hydroxide.
These alkaline components can be diluted with water or the like to adjust the pH for use.

<Dehydration process>
A conventionally known method can be applied as a method of separating polymer particles from the obtained polymer slurry of methacrylic resin.
For example, a dewatering method using a centrifugal separator to shake off water using centrifugal force, a method of suctioning and removing water on a porous belt or on a filtration membrane, and a method of separating polymer particles can be mentioned.

<Drying process>
The polymer in a water-containing state obtained through the above-described dehydration step can be subjected to a drying treatment by a known method and recovered.
For example, hot air drying in which drying is carried out by sending hot air into the tank from a hot air machine or blow heater, etc., vacuum drying in which drying is carried out by heating as necessary after depressurizing the inside of the system, the obtained polymer Water in a container by spinning in a container, spin drying in which drying is performed using centrifugal force, and the like. These methods may be used alone or in combination.
The water content of the resulting methacrylic resin is preferably 0.01% by mass to 1% by mass, more preferably 0.05% by mass to 1% by mass, in consideration of the handleability, color tone, etc. of the resulting resin. %, More preferably 0.1% by mass to 1% by mass, even more preferably 0.27% by mass to 1% by mass. The water content of the resulting methacrylic resin can be measured using the Karl Fischer method.

When manufacturing methacrylic resin using the suspension polymerization method mentioned above, although the methacrylic resin obtained is usually substantially spherical shape, an aggregate may be formed in part.
The term "aggregate" refers to the residue remaining on the sieve when the obtained polymer is passed through a 1.68 mm mesh sieve.
When the aggregates remain in the methacrylic resin, the color tone of the resulting methacrylic resin tends to decrease. The amount of aggregates in the methacrylic resin is preferably 1.2% by mass or less, more preferably 1.0% by mass or less.
The content of aggregates is measured by weight after drying the residue remaining on the sieve through a 1.68 mm mesh sieve in a drying oven at 80 ° C. for 12 hours, and the obtained weight as the total amount of raw materials Agglomerate formation amount (mass%) can be calculated by dividing.

The average particle diameter of the methacrylic resin obtained by using the above-described suspension polymerization method is preferably 0.1 mm or more in consideration of workability at the time of molding and extrusion, etc., and a molded piece obtained by molding More preferably, it is 0.1 mm or more and 1 mm or less, still more preferably 0.1 mm or more and 0.5 mm or less, and still more preferably 0.1 mm or more and 0.4 mm or less.
The average particle size is, for example, a sieve (JTS-200-45-44 (500-m openings) manufactured by Tokyo Screen, 34 (425-m openings), 35 (355-m openings), 36 (300-m openings) based on JIS-Z8801. ), 37 (sieve 250 μm), 38 (sieve 150 μm), 61 (receiver)) Each sieve was sieved for 10 minutes with a vibrating force MAX using a testing machine TSK B-1. It can measure by measuring the particle | grain mass which remained in, and calculating | requiring the particle diameter when mass becomes 50%.

In the present embodiment, when producing a methacrylic resin by a suspension polymerization method, conventionally known suspending agents can be suitably used.
As a suspending agent, water may be charged into the reaction vessel and then charged, and then the maleimide monomer (B) or other monomer species may be charged, and after the maleimide monomer (B) is charged. After the water is introduced, the suspending agent may be introduced before or after the introduction of other monomer species.
The addition amount of the suspending agent can be appropriately selected depending on the polymerization stability at the time of suspension polymerization and the particle diameter to be obtained for the obtained methacrylic resin particles, but the total amount of monomer species used for polymerization is 100 mass When making it into a part, it is preferable that they are 0.01 mass part or more and 2 mass parts or less. The amount is more preferably 0.02 parts by mass or more and 1.5 parts by mass or less, still more preferably 0.03 parts by mass or more and 1.2 parts by mass or less. If the amount is more than 2 parts by mass, a large number of fine particles having a small particle diameter will be generated, which tends to cause problems in the post-treatment step. If the amount is less than 0.01 parts by mass, the particles become too large, and the polymerization stability tends to decrease.
Examples of the suspending agent include, but are not limited to, tricalcium phosphate, hydroxyapatite, magnesium pyrophosphate, magnesium phosphate, aluminum hydroxide, ferric hydroxide, titanium hydroxide, water, for example. Particulate inorganic suspending agents such as magnesium oxide, barium phosphate, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, barium sulfate, talc, kaolin, bentonite, ethyl cellulose, hydroxypropyl methyl cellulose, polyvinyl alcohol and polyacetic acid Organic suspending agents such as partially saponified vinyl can be used. These suspending agents may be used alone or in combination of two or more.

In the method for producing a methacrylic resin according to this embodiment, in addition to the above-described suspension polymerization method, various polymerization methods, namely, polymerization of a polymer to be produced in the polymerization step in bulk polymerization method, solution polymerization method, and emulsion polymerization method A polymerization initiator may be used for the purpose of adjusting the degree.
When a polymerization initiator is used in the suspension polymerization method, bulk polymerization method, solution polymerization method, emulsion polymerization method, in a solution containing a methacrylic acid ester monomer (A) and another vinyl monomer (C) The method of mixing and using is preferable.
When radical polymerization is performed as the polymerization initiator, one having a 10-hour half-life temperature of 40 ° C. or more and 120 ° C. or less is preferable. The polymerization initiator is not limited to the following examples, for example, di-t-butyl peroxide, lauroyl peroxide, stearyl peroxide, benzoyl peroxide, t-butyl peroxy neodecanate, t- Butylperoxypivalate, dilauroyl peroxide, dicumyl peroxide, t-butylperoxy-2-ethylhexanoate, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane Organic peroxides such as 1,1-bis (t-butylperoxy) cyclohexane, azobisisobutyronitrile, azobisisovaleronitrile, 1,1-azobis (1-cyclohexanecarbonitrile), 2, 2'-azobis-4-methoxy-2,4-azobisisobutyronitrile, 2,2'- Zobisu-2,4-dimethylvaleronitrile, mention may be made of conventional radical polymerization initiator azo such as 2,2'-azobis-2-methylbutyronitrile.
One of these may be used alone, or two or more may be used in combination.
These radical polymerization initiators and a suitable reducing agent may be combined and used as a redox initiator.
These polymerization initiators are generally used in a range of 0 to 1 parts by mass with respect to 100 parts by mass of the total amount of all monomers to be used, considering the temperature at which polymerization is performed and the half life of the initiator Can be selected accordingly.
When bulk polymerization method, cast polymerization method or suspension polymerization method is selected, lauroyl peroxide, decanoyl peroxide, and t-butylperoxy--, which are peroxide initiators, from the viewpoint of preventing coloring of methacrylic resin. 2-ethylhexanoate and the like can be particularly preferably used, and lauroyl peroxide is particularly preferably used.

In the method for producing a methacrylic resin according to this embodiment, the molecular weight of the polymer to be produced can be controlled within the range that does not impair the object of the present invention.
For example, the molecular weight can be controlled by using a chain transfer agent such as alkylmercaptans, dimethylacetamide, dimethylformamide or triethylamine, or an iniferter such as dithiocarbamates, triphenylmethylazobenzene or tetraphenylethane derivative, etc. The molecular weight can be adjusted by adjusting the addition amount of these.
When these additives are used, alkyl mercaptans are preferably used from the viewpoint of handleability and stability, for example, n-butyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-tetra Examples include decyl mercaptan, n-octadecyl mercaptan, 2-ethylhexyl thioglycollate, ethylene glycol dithio glycolate, trimethylol propane tris (thioglyco coat), pentaerythritol tetrakis (thio glycolate) and the like.
These can be added as appropriate according to the required molecular weight, but generally they are used in the range of 0.001 to 3 parts by mass with respect to 100 parts by mass of the total amount of all monomers used. .
Other molecular weight control methods include a method of changing the polymerization method, a method of adjusting the amount of the polymerization initiator, a method of changing the polymerization temperature, and the like.
As these molecular weight control methods, only one type of method may be used alone, or two or more types of methods may be used in combination.

[Methacrylic resin]
According to the manufacturing method of the present embodiment described above, the methacrylic acid ester monomer unit (A): 50 to 99% by mass, the maleimide-based monomer unit (B): 1 to 30% by mass, the above (A) and The methacrylic resin which contains 0-20 mass% of other monomer units (C) copolymerizable to (B) is obtained.

(Weight average molecular weight of methacrylic resin, number average molecular weight)
The methacrylic resin produced by the method for producing a methacrylic resin according to this embodiment preferably has a weight average molecular weight of 60,000 to 300,000. The methacrylic resin within this range is excellent in mechanical strength, solvent resistance and flowability. More preferably, it is 60,000 to 250,000, and further preferably 70,000 to 230,000.
The molecular weight distribution (weight-average molecular weight / number-average molecular weight: Mw / Mn) is preferably 1.5 or more and 5 or less in consideration of the balance between flowability, mechanical strength, and solvent resistance. More preferably, it is 1.5 or more and 4.5 or less, more preferably 1.6 or more and 3 or less, and still more preferably 1.6 or more and 2.5 or less.
The weight average molecular weight, number average molecular weight, and peak molecular weight of the methacrylic resin produced by the method for producing a methacrylic resin of the present embodiment are measured by gel permeation chromatography (GPC).
Specifically, the elution time and the elution time are measured using a standard methacrylic resin which is known in advance as a reagent and whose weight average molecular weight, number average molecular weight and peak molecular weight of monodispersion are known and available as a reagent, and high molecular weight components are eluted first. Prepare a calibration curve from the weight average molecular weight. Next, the weight average molecular weight, number average molecular weight, and peak molecular weight of the sample of the methacrylic resin to be measured can be determined from the obtained calibration curve.

[Methacryl-based resin composition]
The methacrylic resin manufactured by this embodiment can be made into a methacrylic resin composition by combining with predetermined other resin mentioned later and a predetermined | prescribed additive.

<Other resin>
The other resins to be combined with the methacrylic resin are not particularly limited as long as they can exhibit the characteristics required for the methacrylic resin, and known thermoplastic resins can be used.
Other resins include, but are not limited to, for example, polypropylene resins, polyethylene resins, polystyrene resins, syndiotactic polystyrene resins, ABS resins, methacrylic resins, AS resins, BAAS -Based resin, MBS resin, AAS resin, biodegradable resin, polycarbonate-ABS resin alloy, polybutylene terephthalate, polyethylene terephthalate, polypropylene terephthalate, polytrimethylene terephthalate, polyalkylene nalylate resin such as polyethylene naphthalate; polyamide resin And polyphenylene ether resins, polyphenylene sulfide resins, and phenol resins.
In particular, AS resin and BAAS resin are preferable in order to improve flowability, and ABS resin and MBS resin are preferable in order to improve impact resistance, and polyester resin is preferable in order to improve chemical resistance.
In addition, polyphenylene ether resins, polyphenylene sulfide resins, phenol resins and the like can be expected to have an effect of improving the flame retardancy.
These resins may be used alone or in combination of two or more.

<Additives>
A predetermined additive may be added to the methacrylic resin obtained by the manufacturing method of the present embodiment in order to impart various characteristics such as rigidity and dimensional stability.
Additives include, but are not limited to, various stabilizers such as, for example, antioxidants, ultraviolet light absorbers, heat stabilizers, light stabilizers, etc .; plasticizers (paraffin-based process oil, naphthene-based process oil, etc. , Aromatic process oil, paraffin, organic polysiloxane, mineral oil), flame retardant (eg, organic phosphorus compound, red phosphorus, phosphorus system such as inorganic phosphate, halogen system, silica system, silicone system etc.), Flame retardant aids (eg, antimony oxides, metal oxides, metal hydroxides, etc.), curing agents (diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, diethylaminopropylamine, 3,9-bis ( 3-Aminopropyl) -2,4,8,10-tetraoxaspiro [5,5] undecane, mensen diami , Amines such as isophorone diamine, N-aminoethyl piperazine, m-xylene diamine, m-phenydamine, diaminophenylmethane, diaminodiphenyl sulfone, dicyandiamide, adipic acid dihydrazide, and phenols such as phenol novolac resin and cresol novolac resin Resins, liquid polymercaptan, polymercaptan such as polysulfide, maleic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyl nadic anhydride, anhydride Pyromellitic acid, methylcyclohexene tetracarboxylic acid anhydride, dodecyl succinic anhydride, trimellitic anhydride, chlorendic anhydride, benzophenone tetracarboxylic acid free Water, acid anhydrides such as ethylene glycol bis (anhydrotrimate), etc., curing accelerators (2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2- Imidazoles such as undecylimidazole, 2-heptadecylimidazole, 2-phenyl-4-methylimidazole, organic phosphines such as triphenylphosphine and tributylphosphine, benzyldimethylamine, 2-dimethylaminomethyl) phenol Tertiary amines such as 2,6-tris (diaminomethyl) phenol and tetramethylhexanediamine, triphenyl phosphine tetraphenyl borate, tetraphenyl phosphonium tetraphenyl borate, triethylamine tetraphenyl borate and the like Quinoid compounds such as boron salts, 1,4-benzoquinone, 1,4-naphthoquinone, 2,3-dimethyl-1,4-benzoquinone, 2,6-dimethylbenzoquinone, 2,3-dimethoxy-1,4-benzoquinone and the like ), Antistatic agents (eg, polyamide elastomers, quaternary ammonium salts, pyridine derivatives, aliphatic sulfonates, aromatic sulfonates, aromatic sulfonate copolymers, sulfates, polyhydric alcohol partial esters Alkyldiethanolamine, alkyldiethanolamide, polyalkylene glycol derivatives, betaines, imidazoline derivatives, etc., conductivity imparting agents, stress relieving agents, release agents (alcohols, and esters of alcohols and fatty acids, and alcohols and dicarboxylic acids) Ester, silicone oil etc), crystallization accelerator, additives Degradation inhibitors, lubricants (for example, higher fatty acids such as stearic acid, behenic acid, zinc stearate, calcium stearate, magnesium stearate and their metal salts, higher fatty acid amides such as ethylene bis stearoamide), impact Additives, sliding properties improvers (hydrocarbons such as low molecular weight polyethylene, higher alcohols, polyhydric alcohols, polyglycols, polyglycerols, higher fatty acids, higher fatty acid metal salts, fatty acid amides, esters of fatty acids and fatty alcohols , Full esters or partial esters of fatty acids and polyhydric alcohols, full esters or partial esters of fatty acids and polyglycols, silicones, fluorocarbons, etc.) compatibilizers, nucleating agents, tougheners, flow control agents, dyes (Nitroso dye, nitro dye, azo dye, stilbene azo dye, ketoimi Dyes, triphenylmethane dyes, xanthene dyes, acridine dyes, quinoline dyes, methine / polymethine dyes, thiazole dyes, indamine / indophenol dyes, azine dyes, oxazine dyes, thiazine dyes, sulfur dyes, aminoketone / oxyketone dyes, anthraquinone dyes , Dyes such as indigoid dyes and phthalocyanine dyes, sensitizers, colorants (titanium oxide, carbon black, titanium yellow, iron oxide pigments, ultramarine blue, cobalt blue, chromium oxide, spinel green, lead chromate pigments, cadmium Based pigments such as inorganic pigments, azo lake pigments, benzimidazolone pigments, diarylide pigments, condensed azo pigments such as azo pigments, phthalocyanine blue, phthalocyanine green pigments such as phthalocyanine green, isoindolinone pigments, quinophthalols Organic pigments such as pigments, quinacridone pigments, perylene pigments, anthraquinone pigments, perinone pigments, fused polycyclic pigments such as dioxazine violet, etc., scaly aluminum metallic pigments, used to improve weld appearance Spherical aluminum pigments, mica powders for pearly metallic pigments, metallic pigments such as those coated with inorganic polyhedral particles such as glass by metal plating or sputtering, etc.), thickeners, anti-settling agents, anti-sagging agents, Fillers (Fiber reinforcing agents such as glass fiber and carbon fiber, glass beads, calcium carbonate, talc, clay etc), antifoaming agents (silicone antifoaming agents, surfactants, polyethers, higher alcohols etc) Organic antifoaming agents, etc.), coupling agents, light diffusing fine particles, antirust agents, antibacterial and antifungal agents, antifouling agents, conductive polymers, etc. And the like.

Examples of the light diffusing fine particles include inorganic fine particles such as alumina, titanium oxide, calcium carbonate, barium sulfate, silicon dioxide and glass beads, and organic fine particles such as styrene crosslinked beads, MS crosslinked beads and siloxane crosslinked beads.
In addition, hollow crosslinked fine particles made of a highly transparent resin material such as acrylic resin, polycarbonate resin, MS resin, cyclic olefin resin, and hollow fine particles made of glass may also be mentioned.
Among the inorganic fine particles, alumina and titanium oxide are more preferable.
The light diffusing fine particles may be used alone or in combination of two or more, and the light diffusing fine particles are not limited at all.
Here, the refractive index of the light diffusing fine particles is preferably 1.7 to 3.0, more preferably 1.7 to 2.5, and still more preferably 1.7 to 2.0. When the refractive index is less than 1.7, the scattering property is too weak, and when it exceeds 3.0, the scattering in the vicinity of the lamp becomes too strong. As a result, unevenness in luminance and emitted light color tone easily occur, which is preferable. Absent.
The refractive index is a value at a temperature of 20 ° C. based on D-line (589 nm). As a method of measuring the refractive index of fine particles, for example, the fine particles are immersed in a liquid whose refractive index can be changed little by little, and the fine particle interface is observed while changing the refractive index of the liquid. And the method of measuring the refractive index of the liquid at that time. An Abbe refractometer or the like can be used to measure the refractive index of the liquid.
The average particle diameter of the light diffusing fine particles is preferably 0.1 to 20 μm, more preferably 0.2 to 15 μm, still more preferably 0.3 to 10 μm, and still more preferably 0.4 to 5 μm. It is preferable that the average particle diameter is 20 μm or less because light loss due to back reflection and the like can be suppressed and the incident light can be efficiently diffused to the light emitting surface side. Moreover, it becomes possible to diffuse emitted light as an average particle diameter is 0.1 micrometer or more, and since desired surface luminescence brightness | luminance and diffusivity can be obtained, it is preferable.
In addition, the content of the light diffusing fine particles in the methacrylic resin composition is 0.0001 to 0.03 mass with respect to 100 parts by mass of the methacrylic resin from the viewpoint of expression of the light diffusion effect and uniformity of surface light emission. Part, preferably 0.0001 to 0.01 parts by mass.

Examples of the heat stabilizer include, but are not limited to, phosphorus-based antioxidants such as hindered phenol-based antioxidants and phosphorus-based processing stabilizers, and particularly, hindered phenol-based oxidations. Inhibitors are preferred.
Examples of hindered phenolic antioxidants include, but are not limited to, pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], thiodiethylene bis. [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 3,3 ′, 3 ', 5,5', 5 ''-hexa-tert-butyl-a, a ', a''-(mesitylene-2,4,6-triyl) tri-p-cresol, 4,6-bis ( Octylthiomethyl) -o-cresol, 4,6-bis (dodecylthiomethyl) -o-cresol, ethylenebis (oxyethylene) bis [3- (5-tert-butyl-4-hydroxy-m-tolyl] ) Propionate], hexamethylene bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 1,3,5-tris (3,5-di-tert-butyl-4-hydroxy) Benzyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, 1,3,5-tris [(4-tert-butyl-3-hydroxy-2,6-xillin) ) Methyl] -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, 2,6-di-tert-butyl-4- (4,6-bis (octylthio) -1 , 3,5-triazin-2-ylamine) phenol and the like. In particular, pentaerythritol terakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] is preferred.
Moreover, you may use a commercially available phenolic antioxidant as a hindered phenolic antioxidant, Although it is not limited as such such a commercially available phenolic antioxidant, For example, Iruga Knox 1010 (Irganox 1010: pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], manufactured by Ciba Specialty Chemicals), Irganox 1076 (Irganox 1076: octadecyl-3) -(3,5-di-t-butyl-4-hydroxyphenyl) propionate, manufactured by Ciba Specialty Chemicals, Irganox 1330 (Irganox 1330: 3, 3 ', 3'', 5, 5', 5) '' -Hexa-t-butyl-a, a ', a''-(mesitylene-2, 4,6-Triyl) tri-p-cresol, manufactured by Ciba Specialty Chemicals, Irganox 3114 (Irganox 3114: 1,3,5-tris (3,5-di-t-butyl-4-hydroxybenzyl) -1,3,5-Triazine-2,4,6 (1H, 3H, 5H) -trione, manufactured by Ciba Specialty Chemicals, Irganox 3125 (Irganox 3125, Ciba Specialty Chemicals), Sumilyzer BHT (Sumilizer BHT, manufactured by Sumitomo Chemical), Cyanox 1790 (Cyanox 1790, manufactured by Cytech), Sumilyzer GA-80 (Sumilizer GA-80, manufactured by Sumitomo Chemical), Sumilyzer GS (Sumilizer GS, manufactured by Sumitomo Chemical), (Vitamin E (Made by Eisai) And the like. Among these also, especially Irganox 1010, Irganox 1076, also be used preferably used Sumilizer GS, and the like. They only singly or in combination of two or more.
Moreover, as a phosphorus antioxidant, although it is not limited to the following, for example, tris (2,4-di-t-butylphenyl) phosphite, bis (2,4-bis (1,1-) Dimethylethyl) -6-methylphenyl) ethyl ester phosphorous acid, tetrakis (2,4-di-t-butylphenyl) (1,1-biphenyl) -4,4′-diyl bis phosphonite, bis (2) , 4-Di-tert-butylphenyl) pentaerythritol diphosphite, bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, bis (2,4-dicumylphenyl) penta Erythritol-diphosphite, tetrakis (2,4-t-butylphenyl) (1,1-biphenyl) -4,4'-diylbisphosphonite, di-t-butyl- - cresyl - phosphonite, and the like.
Furthermore, a commercially available phosphorus-based antioxidant may be used as the phosphorus-based antioxidant, and such a commercially available phosphorus-based antioxidant is not limited to the following, for example, Irgafos 168 ( Irgafos 168: Tris (2,4-di-t-butylphenyl) phosphite (manufactured by Ciba Specialty Chemicals), Irgafos 12 (Irgafos 12: Tris [2-[[2,4,8,10-tetra-] t-Butyldibenzo [d, f] [1,3,2] dioxaphosphefin-6-yl] oxy] ethyl] amine, manufactured by Ciba Specialty Chemicals), Irgafos 38 (Irgafos 38: bis (2 , 4-Bis (1,1-dimethylethyl) -6-methylphenyl) ethyl ester phosphorous acid, manufactured by Ciba Specialty Chemicals Adekastab 329K (ADK STAB 329K, manufactured by Asahi Denka Co., Ltd.), Adekastub PEP 36 (ADK STAB PEP 36, manufactured by Asahi Denka Co., Ltd.), Adekastab PEP-8 (ADK STAB PEP-8, manufactured by Asahi Denka Co., Ltd.), Sandstab P-EPQ (manufactured by Clariant), Weston 618 (Weston 618, manufactured by GE), Weston 619G (Weston 619G, manufactured by GE), Ultranox 626 (Ultranox 626, manufactured by GE), Sumilyzer GP (Sumilizer GP, manufactured by Sumitomo Chemical Co., Ltd.), and the like. These may be used alone or in combination of two or more.
The compounding amount of the above-mentioned heat stabilizer may be any amount as long as it exerts the effects of the present invention, and if it is added in a large amount, it may cause problems such as bleeding out during processing. The amount is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, still more preferably 1 part by mass or less, still more preferably 0.8 parts by mass or less, still more preferably 0. More than 01 parts by mass and less than 0.8 parts by mass.

Examples of the UV absorber include, but are not limited to, benzotriazole compounds, benzotriazine compounds, benzoate compounds, benzophenone compounds, oxybenzophenone compounds, phenol compounds, oxazole compounds, and the like. Examples include malonic acid ester compounds, cyanoacrylate compounds, lactone compounds, salicylic acid ester compounds, and benzoxazinone compounds. In particular, benzotriazole compounds and benzotriazine compounds are preferable. These may be used alone or in combination of two or more.
The UV absorber preferably has a vapor pressure (P) at 20 ° C. of not more than 1.0 × 10 ⁻⁴ Pa from the viewpoint of securing good moldability of the methacrylic resin composition, and 1.0 × It is more preferably 10 ⁻⁶ Pa or less, and still more preferably 1.0 × 10 ⁻⁸ Pa or less.
Here, good molding processability of the methacrylic resin composition means, for example, that when the film is formed as a film, the adhesion of the low molecular weight compound to the roll is small. When it adheres to the roll, it reattaches to the surface, which causes deterioration of the appearance and deterioration of the optical properties.
The melting point (Tm) of the ultraviolet light absorber is preferably 80 ° C. or higher, more preferably 100 ° C. or higher, still more preferably 130 ° C. or higher, and still more preferably 160 ° C. or higher. preferable.
The weight loss of the ultraviolet absorber is preferably 50% or less, more preferably 30% or less, and 15% or less when the temperature is raised from 23 ° C. to 260 ° C. at a rate of 20 ° C./min. Some are more preferable, 10% or less is even more preferable, and 5% or less is even more preferable.
The compounding amount of the ultraviolet light absorber may be an amount that exerts the effects of the present invention, but when it is added in a large amount, it may cause problems such as bleeding out at the time of processing; The content is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, still more preferably 1 part by mass or less, still more preferably 0.8 parts by mass or less, still more preferably 0.01 parts by mass with respect to 100 parts by mass. It is not less than mass part and not more than 0.8 mass part.

[Method for processing methacrylic resin and methacrylic resin composition]
As a method of processing a methacrylic resin, or mixing with the various additives of the said methacrylic resin, and other resin, and processing a methacrylic resin composition, an extruder, a heating roll, a kneader, a roller mixer are mentioned, for example And kneading methods using a kneading machine such as a Banbury mixer.
Among them, kneading by an extruder is preferable in terms of productivity.
The kneading temperature may be in accordance with the preferred processing temperature of the polymer constituting the methacrylic resin and other resins to be mixed, and as a standard, it is in the range of 140 to 300 ° C., preferably in the range of 180 to 280 ° C.

[Molded body]
The molded object of this embodiment is obtained by shape | molding the resin composition which contains the methacrylic resin mentioned above and is individual or contains this methacrylic resin mentioned above.
As a method of producing a molded body, it is possible to mold by a known method such as injection molding, sheet molding, blow molding, injection blow molding, inflation molding, T-die molding, press molding, extrusion molding, foam molding, etc. Secondary processing methods such as pressure forming and vacuum forming can also be used.
In addition, a method of kneading and manufacturing the resin composition using a kneader such as a heating roller, a kneader, a Banbury mixer, an extruder, etc., followed by cooling, crushing and further molding by transfer molding, injection molding, compression molding, etc. It can be mentioned as

[Characteristics of methacrylic resin and molded product]
The methacrylic resin obtained by the method for producing a methacrylic resin according to the present embodiment, and the methacrylic resin composition using the methacrylic resin have high heat resistance and transparency, and further, distortion under high temperature and high humidity conditions. Have excellent moisture-heat resistance with almost no appearance.

(Heat-resistant)
The methacrylic resin of the present embodiment preferably has a VICAT softening temperature of 105 ° C. or higher. The temperature is more preferably 110 ° C. or more, still more preferably 115 ° C. or more, still more preferably 117 ° C. or more, and particularly preferably 120 ° C. or more.
The VICAT softening temperature can be measured in accordance with ISO 306 B50.

(transparency)
From the viewpoint of visibility, the methacrylic resin of the present embodiment preferably has a total light transmittance of 70% or more in a molded article having a thickness of 3 mm. More preferably, it is 75% or more, More preferably, it is 80% or more.
Although it is preferable that the total light transmittance be high, in practical use, the visibility can be sufficiently secured even at 94% or less.
Transparency can be measured by the method described in the examples described later.

(Molding processability)
In the methacrylic resin of the present embodiment, it is preferable that problems such as silver do not occur even when molding processing is performed by lowering the melt viscosity by raising the molding temperature. Specifically, even when molding is continuously performed for 50 shots at a barrel temperature of 290 ° C. and a mold temperature of 60 ° C., it is preferable that almost no molding defects such as silver streaks are observed.

[Use]
The methacrylic resin manufactured by the manufacturing method of this embodiment and the methacrylic resin composition using the same can be suitably used as a material of various molded articles.
As applications of molded articles, for example, household goods, OA equipment, AV equipment, for battery electrical equipment, lighting equipment, housing applications, sanitary applications, elastic play equipment applications, head lamp covers, rear lamp covers, rear combination lamp covers, visors, Glass guards, instrument covers, parts for vehicles such as meter panels, parts for head-up displays for vehicles, liquid crystal displays, plasma displays, organic EL displays, field emission displays, light guide plates used for displays such as rear projection TVs, diffusers, Examples include polarizing plate protective films, quarter wavelength plates, half wavelength plates, viewing angle control films, retardation films such as liquid crystal optical compensation films, display front plates, display substrates, lenses, touch panels, etc. Used for batteries It can be suitably used in that the transparent base and the like. In addition, in the fields of optical communication systems, optical switching systems, and optical measurement systems, it can also be used as waveguides, lenses, optical fibers, optical fiber coating materials, LED lenses, lens covers, and the like. Moreover, it can also be used as a modifier of other resin.
A surface functionalization treatment such as an antireflection treatment, a transparent conductive treatment, an electromagnetic wave shielding treatment, a gas barrier treatment or the like can also be performed on the methacrylic resin of the present embodiment and a molded article using the resin composition thereof.

  Hereinafter, although a specific example and a comparative example are mentioned and explained, the present invention is not limited to these.

〔material〕
The raw materials used in Examples and Comparative Examples described later are shown below.
((A) component: methyl methacrylate (MMA))
: 2.5 ppm of Asahi Kasei Chemicals Co., Ltd. (polymerization inhibitor: 2,4-dimethyl-6-tert-butylphenol manufactured by Chugai Trading Co., Ltd.) (2,4-di-methyl-6-tert-butylphenol) What is added)
((B) component: maleimide monomer)
(B-1): N-phenylmaleimide (N-PMI)
: NIPPON SHOKUBAI CO., LTD., Imirex (registered trademark) -P, melting point 89 ° C, average particle diameter is 4 mm, component content of 0.15 mm or less is 0.5 mass%, component content of 9.5 mm or more The thing of 0.00 mass% and an acid value of 0.6 was used.
(B-2): N-phenylmaleimide (N-PMI)
C., Imirex (registered trademark) -P, melting point 89.degree. C., component (B) having an average particle diameter of 0.9 mm, 0.15 mm or less, obtained by pulverizing the above (B-1). Use of a material with a content of 0.00% by mass or more and 9.5 mm or more. Mp 89 ° C.
(B-3): N-cyclohexylmaleimide (NCyMI)
: NIPPON SHOKUBAI CO., LTD., Imirex (registered trademark) -C, melting point 89 ° C., average particle diameter is 3 mm, component content of 0.15 mm or less is 0.7 mass%, component content of 9.5 mm or more There are used 0.00 mass% and acid value 0.5.
<Method of measuring average particle diameter of component (B), component content of particle diameter of 0.15 mm or less, and component content of particle diameter of 9.5 mm or more>
Sieve based on JIS-Z8801, Tokyo Screen JTS-200-45-16 (opening 9.5 mm), JTS-200-45-19 (opening 5.6 mm), 21 (opening 4.0 mm), 23 (Sieve opening 2.8 mm), 25 (opening 2.0 mm), 32 (opening 0.6 mm), 38 (opening 150 μm), 61 (receiving pan) and using the sieving tester TSK B-1 The particle diameter of 50% by mass was measured using the measured value of the average particle diameter when sieving was performed for 10 minutes with a vibrational force MAX using and the average particle diameter was determined.
In addition, the content of the component having a particle diameter of 0.15 mm or less was obtained by dividing the mass remaining in the receiving tray by the sample mass used for the measurement.
The component content of 9.5 mm or more was determined by dividing the mass remaining on the 9.5 mm sieve by the sample mass used for the measurement.
<Method of measuring acid value of (B) component>
The acid value was measured in accordance with JIS-K-2501-2003.
((C) component: other vinyl monomers)
(C-1): styrene (St)
: Manufactured by Asahi Kasei Chemicals Corporation (C-2-1): methyl acrylate (MA)
: Manufactured by Mitsubishi Chemical Corporation (C-2-2): ethyl acrylate (EA)
: Mitsubishi Chemical Co., Ltd. (C-3): Acrylonitrile (AN)
: Made by Asahi Kasei Chemicals Corporation

(N-octylmercaptan (NOM)): manufactured by Arkema Co., Ltd., used as a chain transfer agent (lauroyl peroxide (LPO)): manufactured by Nippon Oil & Fats Co., Ltd., as a polymerization initiator Use (tertiary calcium phosphate): made by Nippon Chemical Industrial Co., Ltd., used as a suspending agent (calcium carbonate): made by Shiroishi Kogyo Co., Ltd., used as a suspending agent (lauryl sulfate) Sodium (sodium lauryl sulfate): manufactured by Wako Pure Chemical Industries, Ltd., used as a suspension aid

〔Measuring method〕
(I. Measurement of weight average molecular weight)
The weight average molecular weight (Mw) of the methacrylic resin was determined based on the area area in the GPC elution curve and the calibration curve.
As a standard sample for calibration curve, the following 10 kinds of methacrylic resins (manufactured by EasiCal PM-1 Polymer Laboratories) having known monodispersed weight average molecular weights and different molecular weights were used.
Weight average molecular weight Standard sample 1 1,900,000
Standard sample 2 790,000
Standard sample 3 281, 700
Standard sample 4 144,000
Standard sample 5 59,800
Standard sample 6 28, 900
Standard sample 7 13,300
Standard sample 8 5,720
Standard sample 9 1,936
Standard sample 10 1,020

(II. Polymerization time required)
<1. Dissolution method>
The time required for the polymerization to dissolve the maleimide-based monomer (B), the methacrylic acid ester-based monomer (A), and, if necessary, the other vinyl-based monomer (C) is the polymerization required. At the start of measurement of time, the solution was charged into the reaction tank to start polymerization, and the time until the completion of polymerization was measured.
<2. Powder feeding method>
In the powder charging method, the maleimide monomer was supplied to the reaction tank in a solid state.
The time until the completion of the polymerization was measured after starting the introduction of the raw material containing the methacrylic acid ester monomer (A), ie, the raw material other than the (B) maleimide monomer, into the reaction tank.

(III. Aggregate generation amount, polymerization stability)
Aggregates that remain on the screen when the polymerization reaction solution is subjected to a 1.68 mm mesh sieve are collected, and after drying at 85 ° C. for 12 hours, the mass of the aggregate is divided by the mass of the monomer used for the reaction The aggregate generation rate (%) was calculated and used as an index of polymerization stability.
Those with less than 1.0% were evaluated as “「 ”, those with 1.0% or more and less than 2% as“ Δ ”, and those with 2% or more as“ x ”.

(IV. Productivity evaluation)
If the time required for polymerization measured in the above <Dissolution method> and <powder introduction method> exceeds 300 minutes, the evaluation of productivity is not good "x", and the evaluation of productivity is good for those of 300 minutes or less "○" Evaluated as.

(V. Transparency; measurement of total light transmittance)
The total light transmittance was measured using a 3 mm-thick test piece in accordance with the ISO 13468-1 standard, and used as an index of transparency.

(VI. Color tone; measurement of YI)
<Evaluation of Yellowness Difference>
Test pieces of 4 mm in thickness × 40 mm in width × 60 mm in length were molded using methacrylic resin particles manufactured in Examples and Comparative Examples to be described later.
After being placed for 192 hours in a constant temperature and humidity chamber set to the YI value (i) of the test piece, the set temperature 80 ° C., and the set humidity 95% Rh using the Nippon Denshoku Kogyo Co., Ltd. color difference meter 300A Each YI value (ii) was measured, and the change degree of YI value was measured.
The evaluations were made on the assumption that the difference between (ii) and (i) was 1 or more as a defect: “x”, less than 1 as a good: “o”.

(VII. Moisture and heat resistance test)
A test piece 3 mm thick × 100 mm wide × 100 mm long is manufactured at a molding temperature of 270 ° C. and a mold temperature of 60 ° C. using an IS-100EN injection molding machine manufactured by Toshiba Machine Co., Ltd., temperature 90 ° C., humidity 95 The specimen shape after standing for 500 hours in a constant temperature and humidity chamber set in% was observed, and those with deformation such as distortion were seen as “x”, and those with slight deformation were “Δ”, The evaluation was made as "○" when almost no deformation was observed.

Hereafter, the manufacturing method of methacrylic resin is shown.
The compounding amount is shown in Table 1 below.
Moreover, the measurement composition of the preparation composition of a monomer, a weight average molecular weight, and superposition | polymerization conditions are shown in following Table 2.

Example 1
2 kg of water, 65 g of calcium phosphate tribasic, 39 g of calcium carbonate and 0.39 g of sodium lauryl sulfate were charged into a container equipped with a stirrer equipped with a 4-sheet inclined paddle blade to obtain a suspension mixture liquid (a).
Next, solid N-phenylmaleimide in the amount shown in Table 1 below was charged at 25 ° C. into a 60 L reaction vessel having a stirrer attached with three receding wings, and then 26 kg of hot water at about 55 ° C. The mixture was stirred and dispersed.
Then, the said liquid mixture (a) was thrown in, and also raw material mixtures other than N-phenyl maleimide by the compounding quantity shown in following Table 1 were thrown in, and it heated up at 75 degreeC.
Thereafter, suspension polymerization was carried out at about 75 ° C., and an exothermic peak was observed about 140 minutes after the raw material mixture other than N-phenylmaleimide was charged.
Thereafter, the temperature was raised to about 93 ° C. at a rate of 1 ° C./min, followed by aging for 120 minutes to substantially complete the polymerization reaction. The time until the completion of the polymerization was 275 minutes after the start of feeding of the raw material containing the methacrylic acid ester monomer (A) into the reaction tank.
Next, in order to cool to 50 ° C. and dissolve the suspending agent, 20% by mass sulfuric acid was added.
Next, the polymerization reaction solution is sieved through a 1.68 mm mesh to remove aggregates, and water is removed by filtration, and the obtained slurry is dehydrated to obtain a bead-like polymer, and the obtained bead-like polymer is obtained. After washing with water, dehydration was performed as described above, and further washing with ion exchange water and dehydration was repeated to wash, thereby obtaining polymer particles.
The obtained polymer particles were dried in a hot air drying oven at 85 ° C. for 12 hours, and then melt-kneaded using a twin screw extruder of φ30 mm set at a barrel temperature of 240 ° C., and the strands were cooled and cut to obtain resin pellets. . The extrusion workability at that time was good. The injection molded object was manufactured using the obtained pellet, and said evaluation was performed.

Example 2
After charging 26 kg of hot water at about 55 ° C. to the reaction vessel, the temperature in the reaction vessel is maintained at about 55 ° C., solid N-phenylmaleimide is introduced, and the above mixture (a) is shown in Table 1 below. A mixture of raw materials other than N-phenylmaleimide was added in a compounding amount, and the temperature was raised to about 75 ° C. and polymerization was started while maintaining about 75 ° C.
The other conditions were the same as in Example 1.
It took 270 minutes to complete the polymerization reaction after the raw material mixture other than N-phenylmaleimide was charged into the reaction vessel.
The obtained polymer particles were melt-kneaded in the same manner as in Example 1, and the strands were cooled and cut to obtain resin pellets. The injection molded object was manufactured using the obtained pellet, and said evaluation was performed.

[Example 3]
After 26 kg of water at 55 ° C. was charged into the reaction vessel, the mixture was maintained at 55 ° C., the above mixed solution (a) and then solid N-phenylmaleimide were charged, and N-phenyl was added in the amount shown in Table 1 below. A mixture of raw materials other than maleimide was charged to initiate polymerization. The other conditions were the same as in Example 1.
The time from when the raw material mixture other than N-phenylmaleimide was charged into the reaction tank to when the polymerization reaction was completed was 280 minutes.
The obtained polymer particles were melt-kneaded in the same manner as in Example 1, and the strands were cooled and cut to obtain resin pellets. Injection molded articles were produced using the obtained pellets, and the above evaluation was performed.

Example 4
2 kg of water, 65 g of calcium phosphate tribasic, 39 g of calcium carbonate and 0.39 g of sodium lauryl sulfate were charged into a container equipped with a stirrer equipped with a 4-sheet inclined paddle blade to obtain a mixture (a).
Next, solid N-phenylmaleimide in the amount shown in Table 1 below was charged at 25 ° C. into a 60 L reaction vessel having a stirrer attached with three receding wings, and then 26 kg of hot water at approximately 50 ° C. The mixture was stirred and dispersed.
Then, the said liquid mixture (a) was injected | thrown-in, and also the raw material mixture other than the said N- phenyl maleimide was injected | thrown-in with the compounding quantity shown in following Table 1, and it heated up to 75 degreeC.
The other conditions were the same as in Example 1 and polymerization was carried out.
It took 270 minutes to complete the polymerization reaction after the raw material mixture other than N-phenylmaleimide was charged into the reaction vessel.
The obtained polymer particles were melt-kneaded in the same manner as in Example 1, and the strands were cooled and cut to obtain resin pellets. Injection molded articles were produced using the obtained pellets, and the above evaluation was performed.

[Examples 5 to 9]
After 26 kg of warm water at the temperature shown in Table 2 was charged into the reaction tank, solid N-phenylmaleimide was charged while maintaining the temperature, the above mixture (a), and then the compounding amount shown in Table 1 below was N- A mixture of raw materials other than phenyl maleimide was charged, and the temperature was raised to about 75 ° C. and polymerization was started while maintaining about 75 ° C.
The other conditions were the same as in Example 1.
The time from when the raw material mixture other than N-phenyl maleimide is charged into the reaction tank to when the polymerization reaction is completed is shown in Table 2 below.
The obtained polymer particles were melt-kneaded in the same manner as in Example 1, and the strands were cooled and cut to obtain resin pellets. Injection molded articles were produced using the obtained pellets, and the above evaluation was performed.

Comparative Example 1
2 kg of water, 65 g of calcium phosphate tribasic, 39 g of calcium carbonate and 0.39 g of sodium lauryl sulfate were charged into a container equipped with a stirrer equipped with a 4-sheet inclined paddle blade to obtain a mixture (a).
N-phenyl maleimide and the other raw material mixture were mixed and dissolved at 10 ° C. in the amount shown in Table 1 below to obtain a solution (b).
It took 2 hours for the particles of N-phenylmaleimide to be almost invisible by visual observation.
Next, 26 kg of water is charged into a 60 L reactor (reaction tank) having a stirrer equipped with three receding wings, the temperature is raised to 75 ° C., and then the above mixed liquid (a) is charged, and the above dissolved liquid (B) was introduced.
Thereafter, suspension polymerization was carried out at about 80 ° C., and an exothermic peak was observed about 120 minutes after the raw material mixture was charged.
Thereafter, the temperature was raised to 93 ° C. at a rate of 1 ° C./min, followed by aging for 120 minutes to substantially complete the polymerization reaction.
In order to dissolve the maleimide monomer (B) with the methacrylic acid ester monomer (A) and the other vinyl monomer (C), mixing is started to prepare a solution (b). The total time from the charging of solution (b) to the reaction vessel to the completion of polymerization was 365 minutes.
Next, in order to cool to 50 ° C. and dissolve the suspending agent, 20% by mass sulfuric acid was added.
Next, the polymerization reaction solution is sieved through a 1.68 mm mesh to remove aggregates, and water is removed by filtration, and the obtained slurry is dehydrated to obtain a bead-like polymer, and the obtained bead-like polymer is obtained. After washing with water, dehydration was performed as described above, and further washing with ion exchange water and dehydration was repeated to wash, thereby obtaining polymer particles.
The obtained polymer particles were dried in a hot air drying oven at 85 ° C. for 12 hours, and then melt-kneaded using a twin screw extruder of φ30 mm set at a barrel temperature of 240 ° C., and the strands were cooled and cut to obtain resin pellets. . The extrusion workability at that time was good. Injection molded articles were produced using the obtained pellets, and the above evaluation was performed.

Comparative Example 2
(B-2) was used as a maleimide monomer.
The other conditions were the same as in Example 1 and polymerization was performed, and the above evaluation was performed.

Comparative Example 3
N-phenylmaleimide and other raw material mixtures were mixed at 10 ° C. in the amounts shown in Table 1 below.
The mixture was stirred for 3 hours and dissolution was attempted, but a large amount of undissolved N-phenylmaleimide was observed, so heating to 50 ° C. and stirring for an additional 30 minutes resulted in almost no visual confirmation of N-phenylmaleimide particles. The solution was allowed to dissolve (dissolution (b)). The other conditions were the same as in Comparative Example 1 and polymerization was performed, and the above evaluation was performed.

In Examples 1 to 9, compared to the method of dissolving N-phenylmaleimide as in Comparative Example 1, it is possible to significantly reduce the production time while maintaining good polymerization stability. I understand. Moreover, the obtained methacrylic resin also had favorable characteristics.
In addition, as in Examples 1 to 9, use is made of a maleimide-based monomer (containing B-1: 0.5% by mass) and (B-3: contained 0.7% by mass) having a small amount of components of 0.15 mm or less. Compared to the case of using a maleimide-based monomer having a large amount of components of 0.15 mm or less as in Comparative Example 2 (containing B-2: 16% by mass), the method of supplying a solid as it is to a reaction tank is also high. In addition to being able to maintain the polymerization stability, it was found that the color tone stability was also excellent.
Looking at Comparative Example 3, even if stirring is performed for a long time when the amount of maleimide monomer is large, it does not completely dissolve in the raw material mixture, and dissolution by heating is necessary, and the productivity is low. Met.

  The methacrylic resin obtained by the manufacturing method of the present invention is household goods, OA equipment, AV equipment, for battery electrical equipment, lighting equipment, housing applications, sanitary applications, elastic play equipment applications, head lamp covers, rear lamp covers, rear combination lamps Light guide plate used for displays such as covers, visors, bug guards, instrument covers, meter panels, parts for head-up displays for vehicles, liquid crystal displays, plasma displays, organic EL displays, field emission displays, rear projection TVs, etc. Diffusion plate, polarizing plate protective film, quarter wave plate, half wave plate, viewing angle control film, retardation film such as liquid crystal optical compensation film, display front plate, display substrate, lens, touch panel etc. , Or , It can be suitably used in such transparent substrate used in the solar cell. In addition, in the field of optical communication systems, optical switching systems and optical measurement systems, industrially as waveguides, lenses, optical fibers, optical fiber coating materials, LED lenses, lens covers and other resin modifiers There is the availability of.

Claims (7)

Methacrylate ester monomer (A): 50 to 99% by mass,
1 to 30% by mass of maleimide monomer (B),
And other vinyl monomer (C): having a polymerization step of copolymerizing 0 to 20% by mass in a reaction vessel,
The manufacturing method of methacrylic resin which satisfy | fills the conditions of following (1)-(5).
(1) The maleimide monomer (B) is solid at 25 ° C.
(2) The maleimide monomer (B) is supplied to the reaction tank in a solid state.
(3) The content of the particle diameter component of 0.15 mm or less of the maleimide monomer (B) is
It is 3 % by mass or less.
(4) The temperature in the reaction tank at the time of supplying the maleimide monomer (B) in a solid state to the reaction tank is 0 ° C. or more and 80 ° C. or less.
(5) The temperature in the reaction tank when supplying a polymerization monomer other than the maleimide monomer (B) to the reaction tank is 0 ° C. or more and 80 ° C. or less. The method for producing a methacrylic resin according to claim 1, wherein the maleimide monomer (B) is at least one selected from the group consisting of N-phenyl maleimide and N-cyclohexyl maleimide. The method for producing a methacrylic resin according to claim 1, wherein the polymerization step is carried out by a suspension polymerization method. The temperature in the reaction vessel at the time of supplying a monomer component other than the maleimide monomer (B) to the reaction vessel is 10 ° C. or more lower than the melting point of the maleimide monomer (B) , Claim 1
A method for producing a methacrylic resin according to any one of to 3. The method for producing a methacrylic resin according to any one of claims 1 to 4, wherein a content of a particle diameter component of 9.5 mm or more of the maleimide monomer (B) is 10% by mass or less. The method for producing a methacrylic resin according to any one of claims 1 to 5, wherein an average particle diameter of the maleimide monomer (B) is 0.2 mm or more and 9 mm or less. The polymerization process according to any one of claims 1 to 6, wherein a polymerization initiator is supplied to the reaction vessel together with the methacrylic acid ester monomer (A) and the other vinyl monomer (C). The manufacturing method of methacrylic resin as described in any one.