JP2018104721A - Method for producing methacrylic resin, methacrylic resin, and molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for efficiently producing a methacrylic resin high in heat resistance and excellent in color tone, transparency, and moist heat resistance while maintaining high productivity and polymerization stability.SOLUTION: The method for producing a methacrylic resin includes a polymerization step of copolymerizing 50-99 mass% of a methacrylate monomer (A), 1-30 mass% of a maleimide monomer (B), and 0-20 mass% of other vinyl monomers (C) in a reaction tank and satisfies the following conditions (1)-(3): (1) the maleimide monomer (B) is solid at 25°C; (2) the maleimide monomer (B) is supplied in a solid state to the reaction tank; and (3) the content of a component having a particle diameter of 0.15 mm or less in the maleimide monomer (B) is 10 mass% or less.SELECTED DRAWING: None

Description

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

Methacrylic resins typified by polymethyl methacrylate (PMMA) are widely used in the fields of optical materials, lenses, household goods, OA equipment, lighting equipment, and vehicle members because of their high transparency.
In particular, in recent years, use in optical materials such as light guide plates and liquid crystal display films has progressed, and it has also been developed for use assuming high temperature use, and higher heat resistance and optical properties are required. .

Conventionally, as a method for improving the heat resistance of PMMA, a method of introducing a maleimide monomer into a PMMA polymerization system 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 PMMA is polymerized by bulk polymerization or suspension polymerization, the maleimide monomer is a monomer other than the maleimide monomer. The solution is often subjected to a polymerization system after being dissolved in the seed. However, since it takes a long time to dissolve the maleimide monomer in the monomer species, there is a problem that the productivity is poor.
As a method of introducing the maleimide monomer into the PMMA polymerization system without dissolving it, a method of supplying the maleimide monomer as an aqueous dispersion to the polymerization system has been proposed (for example, see Patent Document 3). ). In addition, a method is also disclosed in which a maleimide monomer is directly charged into a reaction vessel and then finely dispersed in the reaction vessel and then subjected to the reaction (see, for example, Patent Document 4).

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

However, in the production methods described in Patent Documents 1 and 2, a maleimide monomer is dissolved in another monomer species to obtain a solution, and the solution is supplied to a reaction vessel so that the polymerization system contains maleimide. Because of the introduction of the monomer, the maleimide monomer is difficult to dissolve in other monomer species, especially in winter and other low-temperature environments, and the solubility is further reduced by the endothermic effect at the time of dissolution. It takes time and there is a problem that there is room for improvement in productivity.
In addition, in the production method described in Patent Document 3, maleimide monomer is finely dispersed in water and continuously fed as a maleimide slurry. In order to improve dispersibility, maleimide monomer Since the particle size of the particles is reduced as much as possible, the surface area of the particles increases, the contact area with water increases, the maleimide tends to hydrolyze, and the acidic components that are generated stabilize the polymerization. In addition, there is a problem that desired characteristics may not be obtained.
In addition, in the production method described in Patent Document 4, after supplying maleimide powder to a reaction vessel, it is subjected to a reaction after finely dispersing maleimide as a solid solution at high temperature.
Even in this method, maleimide is likely to be hydrolyzed, and the polymerization stability may be lowered.
In view of the above-described problems of the prior art, PMMA has high productivity and high characteristics that reduce contact time between water and maleimide monomer particles in order to suppress maleimide hydrolysis. There is a need for a polymerization method.
Therefore, in the present invention, there is provided a method for efficiently producing a methacrylic resin having high heat resistance, excellent color tone and transparency, and excellent wet heat resistance while maintaining high productivity and polymerization stability. This is the issue.

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

[1]
Methacrylic acid ester monomer (A): 50 to 99% by mass,
Maleimide monomer (B) 1-30% by mass,
And other vinyl monomer (C): having a polymerization step of copolymerizing 0 to 20% by mass in a reaction vessel,
A method for producing a methacrylic resin that satisfies the following conditions (1) to (3).
(1) The maleimide monomer (B) is solid at 25 ° C.
(2) The maleimide monomer (B) is supplied to the reaction vessel in a solid state.
(3) In the maleimide monomer (B), the content of a particle size component of 0.15 mm or less is 10% by mass or less.
[2]
The method for producing a methacrylic resin according to [1], wherein the maleimide monomer (B) is at least one selected from the group consisting of N-phenylmaleimide and N-cyclohexylmaleimide.
[3]
The method for producing a methacrylic resin according to [1] or [2], wherein the polymerization step is performed by a suspension polymerization method.
[4]
Any one of [1] to [3], wherein the temperature in the reaction vessel when supplying the maleimide monomer (B) in a solid state to the reaction vessel is 0 ° C. or higher and 80 ° C. or lower. The manufacturing method of methacrylic resin of description.
[5]
The temperature in the reaction vessel when supplying monomer components 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). [1
] The manufacturing method of the methacrylic resin as described in any one of [4].
[6]
The method for producing a methacrylic resin according to any one of [1] to [5], wherein a content of a particle size component of 9.5 mm or more of the maleimide monomer (B) is 10% by mass or less. .
[7]
The method for producing a methacrylic resin according to any one of [1] to [6], wherein the maleimide monomer (B) has an average particle size of 0.2 mm to 9 mm.
[8]
In the polymerization step, the polymerization initiator is supplied to the reaction tank together with the methacrylic acid ester monomer (A) and the other vinyl monomer (C).
[7] The method for producing a methacrylic resin according to any one of [7].
[9]
A methacrylic resin obtained by the method for producing a methacrylic resin according to any one of [1] to [8].
[10]
The molded object obtained by shape | molding the methacrylic resin as described in said [9].

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

Hereinafter, although the form for implementing this invention (henceforth "this embodiment") is demonstrated in detail, this invention is not limited to the following description, In the range of the summary Various modifications can be made.
In the following, the monomer component before polymerization is referred to as “monomer” and “monomer”.
May be omitted. Moreover, the structural unit which comprises a polymer is called "-monomer unit."

[Method for producing methacrylic resin]
In the method for producing a methacrylic resin of this embodiment,
Methacrylic acid ester monomer (A): 50 to 99% by mass,
Maleimide monomer (B) 1-30% by mass,
And the other vinyl-type monomer (C) copolymerizable with said (A) and (B): It has a polymerization process which copolymerizes 0-20 mass% in a reaction tank,
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 vessel in a solid state.
(3) The maleimide monomer (B) has a particle size component content of 0.15 mm or less.
0% by mass or less.
Hereinafter, the manufacturing method of the methacrylic resin of this embodiment will be described in detail.

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

(Methacrylic acid ester monomer (A))
As the methacrylic acid ester monomer (A) (hereinafter referred to as component (A), sometimes referred to as (A)), a monomer represented by the following general formula (1) is preferably used.

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 the carbon.

Examples of the methacrylic acid ester monomer represented by the general formula (1) include, but are not limited to, butyl methacrylate, ethyl methacrylate, methyl methacrylate, propyl methacrylate, isopropyl methacrylate, Examples include cyclohexyl methacrylate, phenyl methacrylate, methacrylic acid (2-ethylhexyl), methacrylic acid (t-butylcyclohexyl), benzyl methacrylate, methacrylic acid (2,2,2-trifluoroethyl), and the like. Methyl methacrylate is preferable from the standpoint of stability.
The said methacrylic acid ester monomer may be used individually by 1 type, and may use 2 or more types together.
The methacrylic acid ester monomer (A) is 50 from the viewpoint of the effect of imparting heat resistance by the maleimide monomer (B) described later in all the monomer components used in the method for producing a methacrylic resin of this embodiment. -99% by mass, preferably 60-95% by mass, more preferably 70-95% by mass, still more preferably 75-95% by mass, and even more preferably 78-95% by mass.
90% by mass is contained.

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

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

Examples of the maleimide monomer (B) include, but are not limited to, maleimide, N-methylmaleimide, N-ethylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N- (o- Chlorophenyl) maleimide, N- (m-chlorophenyl) maleimide, N- (p-chlorophenyl) maleimide and the like.
Preferable examples include N-cyclohexylmaleimide, N-phenylmaleimide, N- (o-chlorophenyl) maleimide, N- (m-chlorophenyl) maleimide, and N- (p-chlorophenyl) maleimide. From the viewpoint of easy availability and imparting heat resistance, more preferred are N-cyclohexylmaleimide and N-phenylmaleimide, and more preferred is N-phenylmaleimide.
The maleimide monomer (B) described above may be used alone or in combination of two or more.

In the method for producing a methacrylic resin of the present embodiment, the maleimide monomer (B) is
It is characterized in that it is supplied to the reaction vessel in a solid state.
By supplying the maleimide monomer (B) to the reaction vessel in a solid state, 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 viewpoints of handling workability and polymerization stability during suspension polymerization of the methacrylic resin. More preferably, it is 0.5 mm-8 mm, More preferably, it is 1 mm-5 mm.
A method for measuring the average particle size of the maleimide monomer (B) is shown below.
For example, a sieve based on JIS-Z8801, JTS-200-45 manufactured by Tokyo Screen
-16 (aperture 9.5 mm), JTS-200-45-19 (aperture 5.6 mm), 21
(Aperture 4.0 mm), 23 (Aperture 2.8 mm), 25 (Aperture 2.0 mm), 32 (
Average particle diameter when sieved with vibration force MAX for 10 minutes using sieve size test machine TSK B-1 using sieve size 0.6 mm), 38 (size 150 μm), 61 (sallet) Using the measured value, a particle diameter of 50% by mass can be measured and determined.
In the method for producing a methacrylic resin of the present embodiment, as described later, the maleimide monomer (B) has a content of a particle size component of 0.15 mm or less of 10% by mass or less. The component content of 0.15 mm or less can be obtained by dividing the mass of the maleimide monomer (B) remaining in the tray by the mass of the entire sample used for the measurement.

Further, when the maleimide monomer (B) is brought into contact with water, it may ring-open to produce 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 of the present embodiment, as described above, specifically, the content of the particle size 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 increase the polymerization stability, after introducing other monomer species other than the component (B) into the reaction vessel, maleimide When supplying the monomer (B) to the reaction vessel, or the maleimide monomer (
When other monomer species other than the component (B) are charged after supplying B) to the reaction vessel, it is preferable that the maleimide monomer (B) is rapidly dissolved in the other monomer species. From the viewpoint of solubility of the maleimide monomer (B) in other monomer species, the maleimide monomer (B)
It is preferable that content of the component of 9.5 mm or more contained in is 10 mass% or less. More preferably, it is 8 mass% or less, More preferably, it is 5 mass% or less.

In addition, from the viewpoint of preventing metal corrosion and polymerization stability in the case of aqueous suspension polymerization, the acid value of the maleimide monomer (B) is preferably 2.0 or less. More preferably, 1.5 or less,
More preferably, it is 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 heat resistance of the methacrylic resin, the maleimide monomer (B) is included in 1 to 30% by mass in all monomers used in the method for producing a methacrylic resin of the present embodiment, Preferably it is 1-25 mass%, More preferably, it is 3-25 mass%, More preferably, it is 5
To 25% by mass, and more preferably 5 to 20% by mass.

(Other vinyl monomers copolymerizable with (A) and (B) (C))
In the method for producing a methacrylic resin of the present embodiment, other vinyl monomers (C) (hereinafter referred to as “copolymers”) that can be copolymerized with the component (A) and the component (B) as long as the effects of the present invention are not impaired. (
C) may be described as component. ) Can be used.
The content in the case of using the other vinyl monomer (C) copolymerizable with the component (A) and the component (B) is different depending on the purpose of use depending on the vinyl monomer used. From the viewpoint of reducing the residual monomer amount and imparting solvent resistance, it is 20% by mass or less, preferably 18% by mass or less, more preferably 15% by mass or less, and further preferably 12% by mass or less in all monomer components. Even more preferably, it is 10% by mass or less.
In addition to the desired properties, the content of component (C) is 0.1% by mass or more based on the total monomers from the viewpoint of appropriately imparting desired properties such as chemical resistance, thermal stability, and reactivity. Is preferably 0.5% by mass or more, and more preferably 1% by mass or more.

The component (C) is not limited to the following, but for example, the following general formula (3)
) Aromatic vinyl monomers represented by general formula (4), acrylic acid ester monomers represented by general formula (4), vinyl cyanide compounds such as acrylonitrile and methacrylonitrile; acrylamide, methacrylamide and the like Amides; Ethylene glycol such as ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, etc. Esterified with methacrylic acid; Hydroxyl ester of two alcohols such as neopentyl glycol di (meth) acrylate and di (meth) acrylate with acrylic acid or methacrylic acid; trimethylolpropane, pentaerythritol Those polyhydric alcohol derivatives etc. esterified with acrylic acid or methacrylic acid; polyfunctional monomers such as divinylbenzene.

In the general formula (3), R ₄ represents 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. R ₅ may be the same group or different groups.
Further, R ₅ may form a ring structure.

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

The component (C) can be used as appropriate according to the required properties. However, when properties such as thermal stability, fluidity, mechanical properties, and chemical resistance are particularly required, an aromatic vinyl-based single component can be used. Monomer (C-1), acrylate monomer (C-2), 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, 2,5 -Dimethylstyrene, 3,4-dimethylstyrene, 3,5-dimethylstyrene, p-ethylstyrene, m-ethylstyrene, о-ethylstyrene, p-ter
t-butylstyrene, 1-vinylnaphthalene, 2-vinylnaphthalene, 1,1-diphenylethylene, isopropenylbenzene (α-methylstyrene), isopropenyltoluene, isopropenylethylbenzene, isopropenylpropylbenzene, isopropenylbutylbenzene, Examples include isopropenylpentylbenzene, isopropenylhexylbenzene, isopropenyloctylbenzene, and the like.
These are appropriately selected according to the required properties in the final methacrylic resin. Among these, styrene and isopropenylbenzene are preferable, and styrene is more preferable from the viewpoint of imparting fluidity and reducing unreacted monomers by improving the polymerization conversion rate.
When using an aromatic vinyl monomer unit (C-1), an aromatic vinyl monomer unit (
The blending ratio (mass ratio) of C-1) and the maleimide monomer (B) is as follows from the viewpoint of processing fluidity during molding, silver streak reduction effect due to residual monomer reduction, and the like. It is preferable to satisfy the formula.
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 even more preferably 1 or less.
Moreover, it is preferable that it is 0.3 or more from a viewpoint of reducing the remaining maleimide-type monomer (B), More preferably, it is 0.35 or more, More preferably, it is 0.4 or more.
The aromatic vinyl monomer (C-1) described above may be used alone or in combination of two or more.

<Acrylic acid ester monomer (C-2)>
Examples of the acrylate monomer include a compound in which the substituent R ₇ is an alkyl group having 1 to 18 carbon atoms in the general formula (4) as described above. In the methacrylic resin obtained by the production method, from the viewpoint of enhancing weather resistance, heat resistance, fluidity, and thermal stability, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, sec sec acrylate -Butyl, 2-ethylhexyl acrylate, etc. are preferred, more preferably methyl acrylate, ethyl acrylate, acrylic acid n
-Methyl acrylate is more preferable from the viewpoint of availability, which is butyl.
The content in the case of using the acrylate monomer (C-2) is (A), (A), (A), from the viewpoint of maintaining the heat resistance imparting effect by the maleimide monomer (B) and imparting thermal stability. B), (C
) When the total of the components is 100 parts by mass, it is preferably 5 parts by mass or less, more preferably 3 parts by mass or less.
The acrylic ester monomer (C-2) may be used alone or in combination of two or more.

<Vinyl cyanide compound (C-3)>
The vinyl cyanide compound is not particularly limited, for example, acrylonitrile,
Examples thereof include methacrylonitrile and vinylidene cyanide. Among them, acrylonitrile is preferably used.
The content in the case of using the vinyl cyanide compound (C-3) is (A), (B) from the viewpoint of maintaining the heat resistance imparting effect by the maleimide monomer (B) and imparting solvent resistance. ), (C
) When the total of the components 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, and particularly preferably 10 parts by mass or less.

(Production process of methacrylic resin)
Next, although the method to manufacture a methacrylic resin using the monomer component mentioned above is demonstrated, the manufacturing method of the 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 of this embodiment is solid at 25 ° C., and is charged into a reaction vessel that performs the polymerization step in a solid state without being dissolved. It is dissolved in the monomer and used for the reaction. The maleimide monomer (B) is dissolved in the reaction vessel by other monomers such as the methacrylic acid ester monomer (A).
Conventionally, the reaction is performed after the maleimide monomer (B), which is a solid raw material, is previously dissolved in a monomer species to be copolymerized therewith or a solvent capable of dissolving the maleimide monomer (B). It was put into the tank and allowed to react.
However, the solubility of the solid maleimide monomer (B) in the methacrylic acid ester monomer (A) to be copolymerized is low. If necessary, a considerable amount of time is required to dissolve the maleimide monomer (B), and much energy is required by stirring and dissolving for a long time. Also, 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 dissolution, and in the dissolution tank, Since it becomes easy to solidify by a transfer pipe from the dissolution tank to the reaction tank, continuous productivity is lowered, which is not preferable.
In the present embodiment, the solid maleimide monomer (B) is directly dissolved without being dissolved.
By supplying to a reaction tank in a solid state, the melt | dissolution time for melt | dissolving a maleimide type monomer (B) can be shortened, and a methacrylic resin can be produced stably.

Methacrylic resins are methacrylate monomers (A) and maleimide monomers (B).
, And other vinyl monomers (C) that can be copolymerized with (A) and (B) as described above, if necessary, solution polymerization method, suspension polymerization method, bulk polymerization method, precipitation polymerization method It can be produced by an emulsion polymerization method. A solution polymerization method, a suspension polymerization method, and a bulk polymerization method are preferably used, a solution polymerization method and a suspension polymerization method are more preferable, and a suspension polymerization method is more preferably used.
When carrying out the polymerization step by suspension polymerization method, if a solid raw material is put into a reaction vessel, if the surface area of the solid raw material is large, hydrolysis due to contact with water occurs, and polymerization proceeds. Stable production may be difficult, for example, the polymerization state may become unstable and solidify at the end of the polymerization. In addition, when exposed to high temperature and high humidity conditions, the color tone may deteriorate.
In the method for producing a methacrylic resin of the present embodiment, in view of the stability of the polymerization state, the content of a particle size 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 charged and reacted in the reaction vessel without dissolving, the maleimide powder having a large surface area is hydrolyzed by contact with water, and the ring is opened. And can effectively prevent the polymerization system from becoming unstable in an acidic state,
While maintaining the polymerization stability, the polymerization time can be shortened and stable production can be achieved, and the production of by-products such as amines derived from hydrolysis of the maleimide monomer (B) is also suppressed. The

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

<Polymerization process>
In the polymerization step, the methacrylic acid ester monomer (A
), A maleimide monomer (B) and, if necessary, other vinyl monomers (C) are copolymerized.
The predetermined reaction tank is not limited to the following, but for example, a vessel with a stirrer, that is, a stirrer can be used, and a monomer, a suspending agent, which is an appropriate raw material in the stirrer, Polymerization is performed by supplying a polymerization initiator, a chain transfer agent, and other additives as necessary to obtain a methacrylic resin slurry.
Upon polymerization, water, suspending agent, solid maleimide monomer (B), methacrylic acid ester monomer (A), and other polymerizable vinyl monomers (C ) Or an additive such as a polymerization initiator is added to the reaction vessel, but the order of addition is not particularly limited as long as the effect of the present invention is obtained. From the viewpoint of ease of handling, it is preferable to supply the polymerization initiator together with the methacrylic acid ester monomer (A) and other vinyl monomers (C).

As an example of the order of charging the solid maleimide monomer (B) into the reaction vessel, (I) a method of charging the maleimide monomer (B) after introducing water, (II) a maleimide monomer in advance body(
B) is introduced into the reaction tank, and then water is added. (III) Water, methacrylic acid ester monomer (A), the above other polymerizable vinyl monomers (C), and polymerization Examples thereof include a method of adding an maleic monomer (B) after adding an additive such as an initiator.
The temperature in the reaction vessel when charging the maleimide monomer (B) is lower than the melting point of the maleimide monomer (B) by 10 ° C. or more from the viewpoint of suppressing ring opening when contacted with water. Is preferable, lower by 20 ° C. or higher, more preferably by 30 ° C. or higher. Specifically, the temperature is preferably 80 ° C. or lower. When water is charged into the reaction vessel in advance, it is preferably 70 ° C. or less, more preferably less than 60 ° C., from the viewpoint of inhibiting hydrolysis of the maleimide monomer (B). The minimum temperature preferred for the charging is preferably a temperature at which water to be used does not solidify, and is preferably 0 ° C. or higher. More preferably 5
It is 10 degreeC or more more preferably.

In addition, when the maleimide monomer (B) is added before adding other monomers,
The stirring time from the addition of the maleimide monomer (B) to the addition of another monomer is not particularly limited, but is preferably 1 to 180 minutes, working efficiency and polymerization stability In consideration of the nature, it is more preferably 1 to 150 minutes, further preferably 5 to 150 minutes, still more preferably 5 to 120 minutes, and still more preferably 10 to 90 minutes.
When water is added after the maleimide monomer (B) is added, or when the maleimide monomer (B) is added after the water is added, the temperature of the water to be added is the suppression of maleimide hydrolysis. From this point of view, the temperature is preferably 10 ° C. or more lower than the melting point of the maleimide monomer (B). That is, it is preferable that the temperature is such that the charged powder does not melt. From the viewpoint of suppressing volatilization, the methacrylic acid ester (A) to be used is preferably 80 ° C. or less, more preferably 75 ° C. or less, still more preferably 70 ° C., and even more preferably 60 ° C.
Is less than. The minimum temperature preferred for the charging is preferably a temperature at which water to be used does not solidify, and is preferably 0 ° C. or higher. More preferably, it is 5 degreeC or more, More preferably, it is 10 degreeC or more, More preferably, it is 20 degreeC or more. The stirring time from addition of water to addition of other monomers is not particularly limited, but is preferably 1 to 180 minutes, more preferably 1 to 150 minutes in consideration of work efficiency, More preferably 5 to 150 minutes, even more preferably 5 to 120 minutes, even more preferably 10 to 90.
Minutes.
The pH of water used in the polymerization process of the methacrylic resin is not particularly limited, but suspension stability,
From the viewpoint of hydrolysis resistance, the pH is preferably in the range of 4-11. More preferably p
H4-9, more preferably pH 4.5-8.

A reaction vessel used in a polymerization process for obtaining a methacrylic resin by suspension polymerization, specifically, a stirrer that is a container equipped with a stirrer includes an inclined paddle blade, a flat paddle blade, a propeller blade, an anchor inside Stirring with stirring blades such as blades, fiddler blades (retracted blades), turbine blades, bull margin blades, max blend blades, full zone blades, ribbon blades, squid blades, supermix blades, intermig blades, special blades, and axial flow blades Examples thereof include known stirring devices such as a device, a stirring device having an excavator blade inside, a stirring device having a chopper blade inside, a stirring device having a disk type, a notch disk type or a screw type rotating disk inside.
The stirring speed at the time of polymerization depends on the type of stirring device used, the stirring efficiency of the stirring blade, the capacity of the polymerization tank, etc., but it is possible to obtain an appropriate particle size, and a component having a particle size of less than 0.15 mm Considering that the amount can be reduced, polymerization stability and the like, it is preferably about 1 to 500 revolutions / minute.

The temperature of the water in the reaction vessel when adding the raw material mixture of the copolymer other than the maleimide monomer (B) constituting the methacrylic resin may be within a range where the effect of the present invention can be exhibited, 0
It is preferable that it is not lower than the boiling point of each raw material to be used. Moreover, it is preferable that it is 20 degreeC or more temperature lower than melting | fusing point of a maleimide-type monomer (B) from a viewpoint of hydrolysis suppression of a maleimide-type monomer (B). More preferably, it is 2 than the melting point of the maleimide monomer (B).
The temperature is 5 ° C. or higher, more preferably 30 ° C. or lower than the melting point of the maleimide monomer (B).
Specifically, the temperature is preferably 80 ° C. or lower, more preferably 70 ° C. or lower, and still more preferably less than 60 ° C. The minimum temperature preferred for the charging is preferably a temperature at which water used for solidification does not solidify, and more preferably 0 ° C. or higher. More preferably, it is 5 degreeC or more, More preferably, it is 10 degreeC or more.

The polymerization temperature in the suspension polymerization step is preferably 40 ° C. or higher and 90 ° C. or lower in consideration of productivity and the amount of aggregates produced. More preferably, it is 50 degreeC or more and 85 degrees C or less, More preferably, it is 60 degreeC or more and 85 degrees C or less, More preferably, it is 65 degreeC or more and 83 degrees C or less.
When manufacturing by suspension polymerization, the time (polymerization time) from the introduction of the monomer component containing the methacrylic ester monomer (A) to the exothermic peak effectively suppresses the exotherm during the polymerization. From the viewpoint of enhancing the polymerization stability, it is preferably 30 minutes or longer and 240 minutes or shorter. More preferably, it is 45 minutes or more and 210 minutes or less, More preferably, it is 60 minutes or more and 210 minutes or less, More preferably, it is 60 minutes or more and 180 minutes or less, More preferably, it is 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) before the polymerization rate does not exceed 20%.
This is preferable because it can be dispersed in the monomer.

Further, from the viewpoint of reducing the residual monomer, it is preferable to raise the temperature to a temperature higher than the polymerization temperature after the polymerization step and hold it for a certain time. Since the temperature at the time of holding | maintenance can raise a polymerization degree, it is preferable that it is temperature higher than polymerization temperature, and it is preferable to heat up 5 degreeC or more from polymerization temperature. When raising temperature, it is preferable that it is below the glass transition temperature of the methacrylic resin obtained from a viewpoint of preventing aggregation of the polymer obtained. Specifically, 120 ° C
Or less, preferably 100 ° C. or less, more preferably 80 ° C. or more and 100 ° C. or less, further preferably 85 ° C. or more and 100 ° C. or less, still more preferably 88 ° C. or more and 100 ° C. or less, and even more preferably 90 ° C. or more and 100 ° C. or less. It is as follows.
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, more preferably 30 minutes or more and 180 minutes, in consideration of the reduction efficiency of the residual monomer. Hereinafter, it is still more preferably 30 minutes or longer and 150 minutes or shorter. If it is the said range, it is possible to reduce the amount of residual monomers effectively.
By performing polymerization according to the polymerization temperature and holding time described above, the amount of aggregates produced is small,
After passing through the drying step described later, methacrylic resin particles having a small residual monomer amount and a small angle of repose can be produced.

<Washing process>
In order to remove the suspending agent, the methacrylic resin slurry obtained through the polymerization step described above is used.
It is preferable to perform operations such as acid washing, water washing and alkali washing.
What is necessary is just to select the optimal frequency | count from the work efficiency and the removal efficiency of a suspension agent as the frequency | count of performing these washing | cleaning operation, and you may repeat once or several times.
What is necessary is just to select the optimal temperature in consideration of the removal efficiency of a suspension agent, the coloring degree of the copolymer obtained, etc. as temperature at the time of washing | cleaning, and it is preferable that it is 20-100 degreeC. More preferably 30-9
It is 5 ° C, more preferably 40 to 95 ° C.
Moreover, it is preferable that the washing | cleaning time per time at the time of washing | cleaning is 10 to 180 minutes from a viewpoint of washing | cleaning efficiency, a repose angle reduction effect, and the simplicity of a process, More preferably, it is 20 to 150 minutes.
The pH of the cleaning solution used at the time of the cleaning may be within a range where the suspension can be removed, but is preferably pH 1-12. The pH for acid washing is preferably pH 1-5, more preferably pH 1.2-4, from the viewpoint of the removal efficiency of the suspending agent and the color tone of the resulting copolymer. The acid used at that time is not particularly limited as long as it can remove the suspending agent. Conventionally known inorganic acids and organic acids can be used. As an example of the acid that is preferably used, the inorganic acid includes hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, boric acid and the like, and each may be used in a diluted solution diluted with water or the like. Examples of the organic acid include those having a carboxyl group, a sulfo group, a hydroxy group, a thiol group, or an enol. Considering the effect of removing the suspending agent and the color tone of the resulting resin, more preferred are nitric acid, sulfuric acid, and organic acids having a carboxyl group.
After the acid cleaning, it is preferable to further perform water washing or alkali washing from the viewpoint of reducing the color tone and angle of repose of the polymer obtained.
The pH of the alkaline solution when performing alkali 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 alkali cleaning, tetraalkylammonium hydroxide, alkali metal hydroxide, alkaline earth metal hydroxide and the like are preferably used. Alkali metal hydroxides and alkaline earth metal hydroxides are more preferable, and lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, magnesium hydroxide, hydroxide are more preferable. Calcium and barium hydroxide are more preferable, lithium hydroxide, sodium hydroxide, potassium hydroxide, magnesium hydroxide and calcium hydroxide are more preferable, and sodium hydroxide and potassium hydroxide are still more preferable.
These alkaline components can be used by adjusting the pH by diluting with water or the like.

<Dehydration process>
As a method of separating the polymer particles from the polymer slurry of the obtained methacrylic resin,
Conventionally known methods can be applied.
For example, a dehydration method using a centrifuge that shakes off water using centrifugal force, a method of sucking and removing water on a perforated belt or a filtration membrane, and separating polymer particles can be mentioned.

<Drying process>
The water-containing polymer obtained through the dehydration step described above can be recovered by performing a drying treatment by a known method.
For example, hot air drying for drying by sending hot air into the tank from a hot air blower or blow heater, etc., vacuum drying for drying by heating as necessary after reducing the pressure inside the system, and the obtained polymer For example, barrel drying for removing moisture by rotating the container in a container, spin drying for drying using centrifugal force, and the like. These methods may be used alone or in combination.
The water content of the obtained methacrylic resin is preferably 0.01% by mass to 1% by mass, more preferably 0.05% by mass, considering the handleability and color tone of the obtained resin.
1 mass%, More preferably, it is 0.1 mass%-1 mass%, More preferably, it is 0.27 mass%-1 mass%. The water content of the resulting methacrylic resin can be measured using the Karl Fischer method.

When a methacrylic resin is produced using the suspension polymerization method described above, the resulting methacrylic resin is usually substantially spherical, but some aggregates may be formed.
The aggregate refers to a residue remaining on the sieve when the obtained polymer is passed through a 1.68 mm mesh sieve.
When the aggregate remains in the methacrylic resin, the color tone of the obtained methacrylic resin tends to decrease. The amount of aggregates in the methacrylic resin is preferably 1.2% by mass or less, and more preferably 1.0% by mass or less.
The agglomerate content was passed through a 1.68 mm mesh sieve, and the weight of what was left on the sieve was dried in a drying oven at 80 ° C. for 12 hours, and the obtained weight was the total amount of raw materials. The aggregate production amount (mass%) can be calculated by dividing the above.

The average particle diameter of the methacrylic resin obtained using the suspension polymerization method described above is preferably 0.1 mm or more in consideration of workability during molding and extrusion, etc., and a molded piece obtained by molding In consideration of the color tone, it is more preferably 0.1 mm or more and 1 mm or less, further 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 diameter is, for example, a sieve based on JIS-Z8801 (JTS-manufactured by Tokyo Screen).
200-45-44 (aperture 500 μm), 34 (aperture 425 μm), 35 (aperture 3
55 [mu] m), 36 (300 [mu] m opening), 37 (250 [mu] m opening), 38 (15 opening)
0 μm), 61 (dish pan)) and vibration force MA using sieving tester TSK B-1
It can be measured by measuring the particle mass remaining on each sieve when sieving with X for 10 minutes and determining the particle diameter when the mass is 50%.

In this embodiment, when a methacrylic resin is produced by a suspension polymerization method, a conventionally known suspending agent can be suitably used.
As the suspending agent, water is added to the reaction tank and then maleimide monomer (B
) Or other monomer species may be added, and after adding the maleimide monomer (B), after adding water, before or after adding other monomer species, the suspension may be added. .
The addition amount of the suspending agent can be appropriately selected depending on the polymerization stability during suspension polymerization and the particle size required for the resulting methacrylic resin particles, but the total amount of monomer species used for the polymerization is 100 mass. Parts, it is preferably 0.01 parts by mass or more and 2 parts by mass or less.
More preferably, they are 0.02 mass parts or more and 1.5 mass parts or less, More preferably, they are 0.03 mass parts or more and 1.2 mass parts or less. When the amount exceeds 2 parts by mass, a large amount of fine particles having a small particle diameter are generated, and problems are likely to occur in the post-treatment process. On the other hand, when the amount is less than 0.01 parts by mass, the particles are too large and the polymerization stability tends to be lowered.
Examples of the suspension include, but are not limited to, for example, tricalcium phosphate, hydroxyapatite, magnesium pyrophosphate, magnesium phosphate, aluminum hydroxide, ferric hydroxide, titanium hydroxide, water Magnesium oxide, barium phosphate, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, barium sulfate, talc,
Particulate inorganic suspensions such as kaolin and bentonite, and organic suspensions such as ethyl cellulose, hydroxypropylmethylcellulose, partially saponified products of polyvinyl alcohol and polyvinyl acetate 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 of the present embodiment, in addition to the suspension polymerization method described above, various polymerization methods, that is, a polymerization step in a bulk polymerization method, a solution polymerization method, and an emulsion polymerization method,
A polymerization initiator may be used for the purpose of adjusting the degree of polymerization of the polymer to be produced.
In the case of using a polymerization initiator in the suspension polymerization method, bulk polymerization method, solution polymerization method or emulsion polymerization method, in a solution containing a methacrylic acid ester monomer (A) and other vinyl monomers (C) The method of mixing and using is preferable.
As the polymerization initiator, when performing radical polymerization, the 10-hour half-life temperature is 40 ° C. or higher 1
What is 20 degrees 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 peroxyneodecanate, t- Butyl peroxypivalate, dilauroyl peroxide, dicumyl peroxide, t
Organic such as butyl peroxy-2-ethylhexanoate, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane Peroxides, azobisisobutyronitrile, azobisisovaleronitrile, 1,1-azobis (1-cyclohexanecarbonitrile), 2,2′-azobis-4-methoxy-2,4-azobisisobuty Ronitrile, 2,2'-azobis-2,4-
Examples include azo-based general radical polymerization initiators such as dimethylvaleronitrile and 2,2′-azobis-2-methylbutyronitrile.
These may be used alone or in combination of two or more.
A combination of these radical polymerization initiators and an appropriate reducing agent may be used as a redox initiator.
These polymerization initiators are generally used in the range of 0 to 1 part by mass with respect to 100 parts by mass of the total amount of all monomers used, taking into consideration the polymerization temperature and the half-life of the initiator. Can be selected as appropriate.
When selecting bulk polymerization method, cast polymerization method, suspension polymerization method, from the viewpoint of preventing coloring of methacrylic resin, peroxide initiators lauroyl peroxide, decanoyl peroxide, and t-butylperoxy- 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 of this embodiment, the molecular weight of the polymer to be produced can be controlled within a range that does not impair the object of the present invention.
For example, the molecular weight can be controlled by using chain transfer agents such as alkyl mercaptans, dimethylacetamide, dimethylformamide, triethylamine, etc., dithiocarbamates, triphenylmethylazobenzene, iniferters such as tetraphenylethane derivatives, etc. It is possible to adjust the molecular weight by adjusting the amount of these added.
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 thioglycolate, ethylene glycol dithioglycolate, trimethylolpropane tris (thioglycolate), pentaerythritol tetrakis (thioglycolate) and the like.
These can be appropriately added according to the required molecular weight, but generally 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, and a method of changing the polymerization temperature.
As these molecular weight control methods, only one type of method may be used alone, or two or more types may be used in combination.

[Methacrylic resin]
According to the manufacturing method of this embodiment mentioned above, a methacrylic acid ester monomer unit (A): 5
0 to 99% by mass, maleimide monomer unit (B): 1 to 30% by mass, (A) and (B
To other monomer units (C): 0 to 20% by mass, a methacrylic resin can be obtained.

(Methacrylic resin weight average molecular weight, number average molecular weight)
The methacrylic resin produced by the methacrylic resin production method of the present embodiment preferably has a weight average molecular weight of 60,000 to 300,000. A methacrylic resin in this range is excellent in mechanical strength, solvent resistance and fluidity. More preferably, it is 60,000-250,000, More preferably, it is 70,000-230,000.
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 fluidity, mechanical strength, and solvent resistance. More preferably, it is 1.5 or more and 4.5 or less, More preferably, it is 1.6 or more and 3 or less, More preferably, it is 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 methacrylic resin production method of the present embodiment are measured by gel permeation chromatography (GPC).
Specifically, using a standard methacrylic resin, which is known in advance and has a monodispersed weight average molecular weight, number average molecular weight, and peak molecular weight, and an analytical gel column that elutes a high molecular weight component first, elution time and Create a calibration curve from the weight average molecular weight. Next, from the obtained calibration curve, 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 obtained.

[Methacrylic resin composition]
The methacrylic resin produced according to the present embodiment can be made into a methacrylic resin composition by combining with a predetermined other resin and a predetermined additive described later.

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

<Additives>
In order to impart various properties such as rigidity and dimensional stability to the methacrylic resin obtained by the production method of the present embodiment, a predetermined additive may be added.
Additives are not limited to the following, but include, for example, various stabilizers such as antioxidants, ultraviolet absorbers, heat stabilizers, light stabilizers; plasticizers (paraffinic process oils, naphthenic process oils). , Aromatic process oils, paraffins, organic polysiloxanes, mineral oils), flame retardants (eg, phosphorus compounds such as organic phosphorus compounds, red phosphorus, inorganic phosphates,
Halogens, silicas, silicones, 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] Amines such as undecane, mensendiamine, isophoronediamine, N-aminoethylpiperazine, m-xylenediamine, m-phenylenediamine, diaminophenylmethane, diaminodiphenylsulfone, dicyandiamide, adipic acid dihydrazide, and phenol novolac resins , Phenol resins such as cresol novolac resin, polymercaptan such as liquid polymercaptan and polysulfide, maleic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride , Methyl nadic anhydride, pyromellitic anhydride, methylcyclohexene tetracarboxylic anhydride, dodecyl succinic anhydride, trimellitic anhydride, chlorendic anhydride, Nzophenone tetracarboxylic acid anhydride, acid anhydrides such as ethylene glycol bis (anhydrotrimate)), curing accelerators (2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2 -Phenylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, imidazoles such as 2-phenyl-4-methylimidazole, organic phosphines such as triphenylphosphine and tributylphosphine, benzyldimethylamine, 2-dimethylaminomethyl )
Tertiary amines such as phenol, 2,4,6-tris (diaminomethyl) phenol, tetramethylhexanediamine, boron salts such as triphenylphosphine tetraphenylborate, tetraphenylphosphonium tetraphenylborate, triethylaminetetraphenylborate, 1,4-benzoquinone, 1,4-naphthoquinone, 2,3-dimethyl-1
, 4-benzoquinone, 2,6-dimethylbenzoquinone, quinoid compounds such as 2,3-dimethoxy-1,4-benzoquinone), antistatic agents (for example, polyamide elastomers, quaternary ammonium salts, pyridine derivatives, aliphatic Sulfonate, aromatic sulfonate, aromatic sulfonate copolymer, sulfate ester salt, polyhydric alcohol partial ester, alkyldiethanolamine, alkyldiethanolamide, polyalkylene glycol derivative, betaine, imidazoline derivative, etc.), conductive Property imparting agent, stress relaxation agent, mold release agent (alcohol and ester of alcohol and fatty acid, ester of alcohol and dicarboxylic acid, silicone oil, etc.), crystallization accelerator, hydrolysis inhibitor, lubricant (for example, Stearic acid, behenic acid, zinc stearate, Higher fatty acids such as calcium allate and magnesium stearate and metal salts thereof, higher fatty acid amides such as ethylene bisstearamide), impact imparting agents, slidability improvers (hydrocarbons such as low molecular weight polyethylene, higher grades) Alcohol, polyhydric alcohol, polyglycol, polyglycerol, higher fatty acid, higher fatty acid metal salt, fatty acid amide, ester of fatty acid and aliphatic alcohol, full ester or partial ester of fatty acid and polyhydric alcohol, fatty acid and polyglycol Full ester or partial ester of
Silicones, fluororesins, etc.), compatibilizers, nucleating agents, reinforcing agents, flow control agents, dyes (nitroso dyes, nitro dyes, azo dyes, stilbene azo dyes, ketoimine dyes, triphenylmethane dyes, xanthene dyes, acridines) Dyes, quinoline dyes, methine / polymethine dyes,
Thiazole dyes, indamine / indophenol dyes, azine dyes, oxazine dyes, thiazine dyes, sulfur dyes, amino ketone / oxyketone dyes, anthraquinone dyes, indigoid dyes, phthalocyanine dyes, etc.), sensitizers, colorants (titanium oxide, carbon) Black, titanium yellow, iron oxide pigments, ultramarine, cobalt blue, chromium oxide, spinel green, lead chromate pigments, cadmium pigments and other inorganic pigments, azo lake pigments, benzimidazolone pigments, diarylide pigments, condensed azo pigments, etc. Azo pigments, phthalocyanine pigments such as phthalocyanine blue, phthalocyanine green, isoindolinone pigments, quinophthalone pigments, quinacridone pigments, perylene pigments, anthraquinone pigments, perinone pigments, dioxazine violet, etc. Organic pigments such as polycyclic pigments, scaly aluminum metallic pigments, spherical aluminum pigments used to improve the weld appearance, mica powder for pearl metallic pigments, and other inorganic materials such as glass Metallic pigments such as those coated with metal plating or sputtering), thickeners, anti-settling agents, sagging inhibitors, fillers (fibrous reinforcing agents such as glass fibers and carbon fibers, and glass beads) , Calcium carbonate, talc, clay, etc.), antifoaming agents (silicone antifoaming agents, surfactants, polyethers, organic antifoaming agents such as higher alcohols, etc.), coupling agents, light diffusing fine particles, rust prevention Agents, antibacterial / antifungal agents, antifouling agents, conductive polymers 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.
Further, hollow crosslinked fine particles made of a highly transparent resin material such as acrylic resin, polycarbonate resin, MS resin, and cyclic olefin resin, hollow fine particles made of glass, and the like are also included.
In the inorganic fine particles, alumina, titanium oxide and the like are more preferable.
The light diffusing fine particles may be used alone or in combination, and is not limited at all.
Here, the refractive index of the light diffusing fine particles is preferably 1.7 to 3.0, more preferably 1.
It is 7-2.5, More preferably, it is 1.7-2.0. If the refractive index is less than 1.7, the scattering property becomes too weak. On the other hand, if it exceeds 3.0, the scattering in the vicinity of the lamp becomes too strong, and as a result, uneven brightness and unevenness in emitted light color tone are likely to occur. Absent.
The refractive index is a value at a temperature of 20 ° C. based on the D line (589 nm). As a method for measuring the refractive index of the 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. The method of measuring the refractive index of the liquid at the time is mentioned. 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.
. 2-15 μm, more preferably 0.3-10 μm, even more preferably 0.4-5
μm. An average particle diameter of 20 μm or less is preferable because light loss due to back reflection or the like is suppressed and incident light can be efficiently diffused to the light emitting surface side. In addition, it is preferable that the average particle diameter is 0.1 μm or more because emitted light can be diffused and desired surface emission luminance and diffusibility can be obtained.
In addition, the content of the light diffusing fine particles in the methacrylic resin composition is 0.0001 to 0.0 with respect to 100 parts by mass of the methacrylic resin from the viewpoint of the expression of the light diffusing effect and the uniformity of surface emission.
3 parts by mass, preferably 0.0001 to 0.01 parts by mass.

Examples of the heat stabilizer include, but are not limited to, phosphorus antioxidants such as hindered phenol antioxidants and phosphorus processing stabilizers. Inhibitors are preferred.
Examples of the hindered phenol antioxidant 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], hexamethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate]
1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) -1,3
, 5-Triazine-2,4,6 (1H, 3H, 5H) -trione, 1,3,5-tris [
(4-tert-butyl-3-hydroxy-2,6-xylin) 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 preferable.
Commercially available phenolic antioxidants may be used as hindered phenolic antioxidants. Examples of such commercially available phenolic antioxidants include, but are not limited to, Knox 1010 (Irganox 1010: pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], manufactured by Ciba Specialty Chemicals), Irganox 1076 (Ir
ganox 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,
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, manufactured by Ciba Specialty Chemicals), Sumilyzer BHT (Sumilizer BH
T, manufactured by Sumitomo Chemical), Cyanox 1790 (Cyanox 1790, manufactured by Cytec),
Sumilyzer GA-80 (Sumilizer GA-80, manufactured by Sumitomo Chemical), Sumilyzer GS (Sumilizer GS, manufactured by Sumitomo Chemical), (Vitamin E (manufactured by Eisai)), etc. Among them, Irganox 1010, Irganox 1076, It is preferable to use a milizer GS etc. These may be used alone or in combination of two or more.
Moreover, as a phosphorus antioxidant, although 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′-diylbisphosphonite, bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite, bis (2,6 -Di-t-butyl-4-methylphenyl) pentaerythritol diphosphite, bis (2,4-dicumylphenyl) pentaerythritol diphosphite, tetrakis (2,4-t-butylphenyl) (1,1-biphenyl) ) -4,4′-diylbisphosphonite, di-t-butyl-m-cresyl-phosphonite and the like.
Furthermore, a commercially available phosphorus antioxidant may be used as the phosphorus antioxidant. Examples of such commercially available phosphorus antioxidants are not limited to the following, but include Irgaphos 168 ( Irgafos 168: Tris (2,4-di-t-butylphenyl) phosphite, manufactured by Ciba Specialty Chemicals), Irgafos 12 (Irga
fos 12: Tris [2-[[2,4,8,10-tetra-t-butyldibenzo [d, f] [
1,3,2] dioxaphosphine-6-yl] oxy] ethyl] amine, manufactured by Ciba Specialty Chemicals, Irgafos 38 (bis (2,4
-Bis (1,1-dimethylethyl) -6-methylphenyl) ethyl ester phosphorous acid (manufactured by Ciba Specialty Chemicals), ADK STAB 329K (ADK STAB 3
29K, manufactured by Asahi Denka), ADK STAB PEP36 (ADK STAB PEP36, manufactured by Asahi Denka), ADK STAB PEP-8 (ADK STAB PEP-8, manufactured by Asahi Denka), Sand
stab P-EPQ (manufactured by Clariant), Weston 618 (Weston 618,
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.). These may be used alone or in combination of two or more.
The amount of the heat stabilizer mentioned above may be an amount that exhibits the effect of the present invention, and if it is excessively added, a problem such as bleeding out during processing may occur. It 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, and still more preferably 0.8 parts by mass or less with respect to 100 parts by mass of the resin. 01 parts by mass or more and 0.8 parts by mass or less.

Examples of the ultraviolet absorber include, but are not limited to, for example, benzotriazole compounds, benzotriazine compounds, benzoate compounds, benzophenone compounds, oxybenzophenone compounds, phenol compounds, oxazole compounds,
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.
From the viewpoint of ensuring good moldability of the methacrylic resin composition, the ultraviolet absorber is 2
The vapor pressure (P) at 0 ° C. is preferably 1.0 × 10 ⁻⁴ Pa or less, and 1.0 × 1
0 ⁻⁶ Pa or less is more preferable, and 1.0 × 10 ⁻⁸ Pa or less is further preferable.
Here, the favorable moldability of the methacrylic resin composition means, for example, that the low-molecular compound adheres less to the roll when it is molded as a film. When it adheres to the roll, it reattaches to the surface, which causes the appearance to deteriorate and the optical characteristics to deteriorate.
The melting point (Tm) of the ultraviolet absorber is preferably 80 ° C. or higher, more preferably 100 ° C. or higher, further preferably 130 ° C. or higher, and even more preferably 160 ° C. or higher. preferable.
The ultraviolet absorber preferably has a weight reduction rate of 50% or less, more preferably 30% or less, when the temperature is increased from 23 ° C. to 260 ° C. at a rate of 20 ° C./min, 15%
Or less, more preferably 10% or less, still more preferably 5% or less.
The blending amount of the ultraviolet absorber may be an amount that exhibits the effect of the present invention. However, if it is excessively added, there is a possibility that problems such as bleeding out during processing may occur. The amount is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, further preferably 1 part by mass or less, still more preferably 0.8 parts by mass or less, and still more preferably 0.01 parts by mass with respect to 100 parts by mass. It is not less than 0.8 parts by mass.

[Processing of methacrylic resin and methacrylic resin composition]
Examples of methods for processing a methacrylic resin composition, or mixing various additives of the methacrylic resin and other resins to process a methacrylic resin composition include, for example, an extruder, a heating roll, a kneader, and a roller mixer. And a kneading method using a kneading machine such as a Banbury mixer.
Among these, kneading with 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. As a guideline, it is in the range of 140 to 300 ° C, preferably 180 to 280 ° C.
Range.

[Molded body]
The molded body of the present embodiment includes the methacrylic resin described above, and is obtained by molding the above methacrylic resin alone or a resin composition including the methacrylic resin.
As a manufacturing method of the molded body, it can be molded by known methods such as injection molding, sheet molding, blow molding, injection blow molding, inflation molding, T-die molding, press molding, extrusion molding, foam molding, Secondary processing molding methods such as pressure forming and vacuum forming can also be used.
Another example is a method in which a resin composition is kneaded and produced using a kneader such as a heating roll, kneader, Banbury mixer, extruder, etc., then cooled, pulverized, and further molded by transfer molding, injection molding, compression molding, or the like. Can be mentioned.

[Characteristics of methacrylic resin and molded product]
In the methacrylic resin obtained by the method for producing a methacrylic resin of the present embodiment, and in the methacrylic resin composition using the methacrylic resin, high heat resistance and transparency, and further, distortion under high temperature and high humidity conditions Has excellent moisture and heat resistance.

(Heat-resistant)
The methacrylic resin of this embodiment preferably has a VICAT softening temperature of 105 ° C. or higher. More preferably, it is 110 degreeC or more, More preferably, it is 115 degreeC or more, More preferably, it is 117 degreeC or more, Most preferably, it is 120 degreeC or more.
The VICAT softening temperature can be measured according to 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 product 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 is high, practically sufficient visibility can be secured even at 94% or less.
Transparency can be measured by the method described in Examples described later.

(Molding processability)
In the methacrylic resin of the present embodiment, it is preferable that defects such as silver do not occur even when the molding temperature is lowered to lower the melt viscosity to perform molding. Specifically, it is preferable that molding defects such as silver streak are hardly observed even when 50 shots are continuously formed at a barrel temperature of 290 ° C. and a mold temperature of 60 ° C.

[Use]
The methacrylic resin produced by the production method of the present embodiment and the methacrylic resin composition using the methacrylic resin can be suitably used as materials for various molded products.
Applications of the molded body include, for example, household goods, OA equipment, AV equipment, battery electrical equipment, lighting equipment, housing use, sanitary use, elastic play equipment use, head lamp cover, rear lamp cover, rear combination lamp cover, visor, Vehicle parts such as bug guards, instrument covers, and meter panels, parts for vehicle head-up displays, liquid crystal displays, plasma displays, organic EL displays, field emission displays, rear projection televisions, light guide plates, diffuser plates, Examples include polarizing plate protective films, quarter-wave plates, half-wave plates, viewing angle control films, retardation films such as liquid crystal optical compensation films, display front plates, display substrates, lenses, touch panels, and the like. 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, waveguides, lenses,
It can also be used for optical fibers, optical fiber coating materials, LED lenses, lens covers, and the like. It can also be used as a modifier for other resins.
The molded body using the methacrylic resin and the resin composition of the present embodiment can be subjected to surface functionalization treatment such as antireflection treatment, transparent conductive treatment, electromagnetic wave shielding treatment, and gas barrier treatment.

Hereinafter, although a specific Example and a comparative example are given and demonstrated, this invention is not limited to these.

〔material〕
It shows below about the raw material used in the Example and comparative example which are mentioned later.
((A) component: methyl methacrylate (MMA))
: Asahi Kasei Chemicals Co., Ltd. (2.5 ppm of 2,4-di-6-tert-butylphenol as a polymerization inhibitor, manufactured by Chugai Trading Co., Ltd.) 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 size 4
The component content of 0.15 mm or less was 0.5 mass%, the component content of 9.5 mm or more was 0.00 mass%, and the acid value was 0.6.
(B-2): N-phenylmaleimide (N-PMI)
: Nippon Shokubai Co., Ltd., Imirex (registered trademark) -P, melting point 89 ° C., (B-1)
The content of components having an average particle size of 0.9 mm and 0.15 mm or less obtained by pulverizing
, 9.5 mm or more component content 0.00 mass% used. Melting point 89 ° C.
(B-3): N-cyclohexylmaleimide (NCyMI)
: Nippon Shokubai Co., Ltd., Imirex (registered trademark) -C, melting point 89 ° C., average particle size 3
The component content of 0.15 mm or less is 0.7 mass%, the component content of 9.5 mm or more is 0.00 mass%, and the acid value is 0.5.
<Measurement Method of (B) Component Average Content, Component Content of Particle Size of 0.15 mm or Less, and Component Content of Particle Size of 9.5 mm or More>
Sieve based on JIS-Z8801, JTS-200-45-16 (Tokyo Screen)
(Aperture 9.5 mm), JTS-200-45-19 (Aperture 5.6 mm), 21 (Aperture 4.0 mm), 23 (Aperture 2.8 mm), 25 (Aperture 2.0 mm), 32 (Open 0
. 6 mm), 38 (aperture 150 μm), 61 (a saucer), and the measured value of the average particle diameter when sieving for 10 minutes with vibration force MAX using a screening tester TSK B-1. The particle size of 50% by mass was measured and the average particle size was determined.
In addition, the content of components having a particle size of 0.15 mm or less was obtained by dividing the mass remaining in the tray by the sample mass used for the measurement.
The component content of 9.5 mm or more was obtained by dividing the mass remaining on the sieve having a mesh size of 9.5 mm by the sample mass used for the measurement.
<Method for Measuring Acid Value of Component (B)>
The acid value was measured according to JIS-K-2501-2003.
((C) component: other vinyl monomers)
(C-1): Styrene (St)
: Asahi Kasei Chemicals Corporation (C-2-1): Methyl acrylate (MA)
: Mitsubishi Chemical Corporation (C-2-2): Ethyl acrylate (EA)
: Made by Mitsubishi Chemical Corporation (C-3): Acrylonitrile (AN)
: Asahi Kasei Chemicals Corporation

(N-octylmercaptan (NOM)): manufactured by Arkema Co., Ltd.
Used as a chain transfer agent (lauroyl peroxide (LPO)): manufactured by NOF Corporation, used as a polymerization initiator (calcium phosphate): manufactured by Nippon Chemical Industry Co., Ltd. Used as suspension (calcium calbonate): Shiraishi Kogyo Co., Ltd., used as suspension (sodium lauryl sulfate): Wako Pure Chemical Industries, Ltd., suspension aid Used as

〔Measuring method〕
(I. Measurement of weight average molecular weight)
Based on the area area in the GPC elution curve and the calibration curve, the weight average molecular weight (Mw) of the methacrylic resin was determined.
The following 10 methacrylic resins (manufactured by EasiCal PM-1 Polymer Laboratories) having different molecular weights and known monodispersed weight average molecular weights were used as standard samples for calibration curves.
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. Time required for polymerization)
<1. Dissolution method>
Polymerization required at the time when mixing was started to dissolve the maleimide monomer (B), the methacrylic acid ester monomer (A), and other vinyl monomers (C) as required. At the start of time measurement, the solution was put into the reaction vessel to start the polymerization, and the time until the polymerization was completed was measured.
<2. Powder input method>
In the powder charging method, the maleimide monomer was supplied to the reaction vessel in a solid state.
The time from the start of the introduction of the raw material containing the methacrylic ester monomer (A) into the reaction vessel, that is, the raw material other than the maleimide monomer (B), was measured until the polymerization was completed.

(III. Aggregate generation amount, polymerization stability)
When the polymerization reaction solution is passed through a 1.68 mm mesh sieve, agglomerates remaining on the sieve are collected,
The mass of the aggregate after drying at 85 ° C. for 12 hours was divided by the mass of the monomer used in the reaction to calculate the aggregate generation rate (%), which was used as an index of polymerization stability.
Evaluation was made with “◯” for less than 1.0%, “Δ” for 1.0% or more and less than 2%, and “x” for 2% or more.

(IV. Productivity evaluation)
When the time required for polymerization measured in the above <dissolution method> and <powder charging method> exceeds 300 minutes, the productivity evaluation is not good “x”, and when the time required for the polymerization is 300 minutes or less, the productivity evaluation is good “◯”. As evaluated.

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

(VI. Color tone; YI measurement)
<Evaluation of yellowness difference>
Using the methacrylic resin particles produced in Examples and Comparative Examples described later, the thickness is 4 m.
A test piece of m × width 40 mm × length 60 mm was formed.
Using Nippon Denshoku Industries Co., Ltd. color difference meter 300A, the YI value (i) of the test piece, and
YI after 192 hours in a constant temperature and humidity chamber set at a set temperature of 80 ° C. and a set humidity of 95% Rh
Each value (ii) was measured, and the degree of change in the YI value was measured.
When the difference between the above (ii) and the above (i) was 1 or more, the evaluation was made as “bad”: “x”, and “less”: less than 1: “◯”.

(VII. Moist heat resistance test)
Using a IS-100EN injection molding machine manufactured by Toshiba Machine Co., Ltd., a test piece having a thickness of 3 mm, a width of 100 mm and a length of 100 mm was produced at a molding temperature of 270 ° C. and a mold temperature of 60 ° C., and a temperature of 90 ° C.
, The shape of the test piece after observing it for 500 hours in a constant temperature and humidity chamber set at a humidity of 95% was observed. Evaluation was made as “◯” when “Δ” or almost no deformation was observed.

Hereafter, the manufacturing method of methacrylic resin is shown.
The blending amounts are shown in Table 1 below.
In addition, Table 2 below shows the charged composition of the monomer, the measurement result of the weight average molecular weight, and the polymerization conditions.

[Example 1]
2 kg of water, 65 g of tribasic calcium phosphate, 39 g of calcium carbonate, and 0.39 g of sodium lauryl sulfate were charged into a container having a stirrer equipped with four inclined paddle blades to obtain a suspension mixture (a).
Next, a solid N-phenylmaleimide in the amount shown in Table 1 below was charged at 25 ° C. into a 60 L reaction tank equipped with a stirrer equipped with three receding blades, and then 26 kg of hot water at about 55 ° C. was charged. And dispersed with stirring.
Subsequently, the above mixed solution (a) was added, and further a raw material mixture other than N-phenylmaleimide was added in the blending amounts shown in Table 1 below, and the temperature was raised to 75 ° C.
Thereafter, suspension polymerization was carried out at about 75 ° C., and an exothermic peak was observed about 140 minutes after the starting material mixture other than the N-phenylmaleimide was added.
Thereafter, the temperature was raised to about 93 ° C. at a rate of 1 ° C./min and then aged for 120 minutes to substantially complete the polymerization reaction. The time from the start of charging the raw material containing the methacrylic acid ester monomer (A) into the reaction vessel until the polymerization was completed was 275 minutes.
Next, in order to cool to 50 ° C. and dissolve the suspending agent, 20 mass% sulfuric acid was added.
Next, the polymerization reaction solution is passed through a 1.68 mm mesh sieve to remove aggregates, the water is filtered off, the resulting slurry is dehydrated to obtain a bead polymer, and the resulting bead polymer is After washing with water, it was dehydrated in the same manner as described above, and further washed with ion-exchanged water and repeated dehydration to obtain polymer particles.
The obtained polymer particles were dried in a hot air drying oven at 85 ° C. for 12 hours, then melt-kneaded in a φ30 mm twin screw extruder 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. Using the obtained pellets, an injection molded article was produced and evaluated as described above.

[Example 2]
After charging 26 kg of hot water at about 55 ° C. into the reaction vessel, the temperature inside the reaction vessel is maintained at about 55 ° C.,
Solid N-phenylmaleimide was added, the above mixture (a), and then a raw material mixture other than N-phenylmaleimide were added in the blending amounts shown in Table 1 below, and the temperature was raised to about 75 ° C to about 75 ° C.
And the polymerization was started.
The other conditions were the same as in Example 1.
The time from the introduction of the raw material mixture other than N-phenylmaleimide into the reaction vessel until the completion of the polymerization reaction was 270 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. Using the obtained pellets, an injection molded article was produced and evaluated as described above.

Example 3
After putting 26 kg of water at 55 ° C. into the reaction vessel, the mixture was kept at 55 ° C., the above-mentioned mixed solution (a) and then solid N-phenylmaleimide were added, and N-phenyl in the blending amount shown in Table 1 below. Polymerization was started by charging a raw material mixture other than maleimide. Other conditions are as in Example 1.
The operation was performed in the same manner as above.
The time from the introduction of the raw material mixture other than N-phenylmaleimide into the reaction vessel until the completion of the polymerization reaction 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. Using the obtained pellets, an injection molded product was produced and evaluated.

Example 4
2 kg of water, 65 g of tricalcium phosphate, 39 g of calcium carbonate, and 0.39 g of sodium lauryl sulfate were charged into a container having a stirrer equipped with four inclined paddle blades to obtain a mixed solution (a).
Next, a solid N-phenylmaleimide of the amount shown in Table 1 below was charged at 25 ° C. into a 60 L reaction tank equipped with a stirrer equipped with three reverse blades, and then 26 kg of hot water at about 50 ° C. was charged. And dispersed with stirring.
Subsequently, the mixed solution (a) was added, and a raw material mixture other than the N-phenylmaleimide was added in the blending amounts shown in Table 1 below, and the temperature was raised to 75 ° C.
The other conditions were the same as in Example 1, and polymerization was performed.
The time from the introduction of the raw material mixture other than N-phenylmaleimide into the reaction vessel until the completion of the polymerization reaction was 270 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. Using the obtained pellets, an injection molded product was produced and evaluated.

[Examples 5 to 9]
After charging 26 kg of hot water having the temperature shown in Table 2 into the reaction tank, the temperature was maintained and solid N
-Phenylmaleimide was added, and the mixture (a), then N-
A raw material mixture other than phenylmaleimide was added, and the temperature was raised to about 75 ° C. and maintained at about 75 ° C. to initiate polymerization.
The other conditions were the same as in Example 1.
Table 2 below shows the time from the introduction of the raw material mixture other than N-phenylmaleimide into the reaction vessel until the completion of the polymerization reaction.
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. Using the obtained pellets, an injection molded product was produced and evaluated.

[Comparative Example 1]
2 kg of water, 65 g of tricalcium phosphate, 39 g of calcium carbonate, and 0.39 g of sodium lauryl sulfate were charged into a container having a stirrer equipped with four inclined paddle blades to obtain a mixed solution (a).
N-phenylmaleimide and other raw material mixtures were mixed and dissolved at 10 ° C. in the blending amounts shown in Table 1 below to obtain a solution (b).
It took 2 hours until the N-phenylmaleimide particles could hardly be visually confirmed.
Next, 26 kg of water was added to a 60 L reactor (reaction tank) having a stirrer equipped with three receding blades.
Was added, the temperature was raised to 75 ° C., then the mixed solution (a) was added, and the dissolved solution (b) was added.
Thereafter, suspension polymerization was carried out while maintaining the temperature at about 80 ° C., and an exothermic peak was observed about 120 minutes after the starting material mixture was added.
Thereafter, the temperature was raised to 93 ° C. at a rate of 1 ° C./min and then aged for 120 minutes to substantially complete the polymerization reaction.
Mixing was started to dissolve the maleimide monomer (B) and the methacrylic acid ester monomer (A) and the other vinyl monomer (C) to prepare a solution (b). The total time from the introduction of the solution (b) into the reaction vessel to the completion of the polymerization was 365 minutes.
Next, in order to cool to 50 ° C. and dissolve the suspending agent, 20 mass% sulfuric acid was added.
Next, the polymerization reaction solution is passed through a 1.68 mm mesh sieve to remove aggregates, the water is filtered off, the resulting slurry is dehydrated to obtain a bead polymer, and the resulting bead polymer is After washing with water, it was dehydrated in the same manner as described above, and further washed with ion-exchanged water and repeated dehydration to obtain polymer particles.
The obtained polymer particles were dried in a hot air drying oven at 85 ° C. for 12 hours, then melt-kneaded in a φ30 mm twin screw extruder 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. Using the obtained pellets, an injection molded product was produced and evaluated.

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

[Comparative Example 3]
N-phenylmaleimide and other raw material mixtures were mixed at 10 ° C. in the blending amounts shown in Table 1 below.
Stirring was performed for 3 hours, and dissolution was attempted. However, since many undissolved residues of N-phenylmaleimide were observed, the mixture was heated to 50 ° C. and further stirred for 30 minutes, and N-phenylmaleimide particles could hardly be visually confirmed. (Dissolved solution (b)). The other conditions were the same as in Comparative Example 1, and the above evaluation was performed.

In Examples 1-9, compared with the method of dissolving N-phenylmaleimide as in Comparative Example 1, production time can be greatly shortened while maintaining good polymerization stability. I understood. The obtained methacrylic resin also had good characteristics.
Further, as in Examples 1 to 9, a maleimide monomer (B
-1: 0.5% by mass contained), (B-3: 0.7% by mass contained), and when a maleimide monomer having many components of 0.15 mm or less is used as in Comparative Example 2. (B-2: 16% by mass
It was found that even when the solid was fed to the reaction vessel as a solid, high polymerization stability could be maintained and color tone stability was excellent.
Looking at Comparative Example 3, when the amount of maleimide monomer is large, even if it is stirred for a long time, it does not completely dissolve in the raw material mixture, and it must be dissolved by heating, resulting in low productivity. Met.

The methacrylic resin obtained by the production method of the present invention is used for household goods, OA equipment, AV equipment, battery electrical equipment, lighting equipment, housing use, sanitary use, elastic play equipment use, head lamp cover, rear lamp cover, rear combination lamp. Cover, visor, bug guard,
Light guide plate, diffuser plate, polarizing plate used in displays such as instrument covers, meter panels, vehicle head-up display components, liquid crystal displays, plasma displays, organic EL displays, field emission displays, rear projection televisions, etc. Protective film, 1/4 wavelength plate, 1/2 wavelength plate, viewing angle control film, retardation film such as liquid crystal optical compensation film, display front plate, display substrate, lens,
A touch panel etc. are mentioned, Moreover, it can use suitably for the transparent base | substrate etc. which are used for a solar cell. In addition, in the fields of optical communication systems, optical switching systems, and optical measurement systems, as waveguides, lenses, optical fibers, optical fiber coating materials, LED lenses, lens covers, and other resin modifiers, There is a possibility of use.

[1]
Methacrylic acid ester monomer (A): 50 to 99% by mass,
Maleimide monomer (B) 1-30% by mass,
And other vinyl monomer (C): having a polymerization step of copolymerizing 0 to 20% by mass in a reaction vessel,
A method for producing a methacrylic resin that satisfies the following conditions (1) to (5) .
(1) The maleimide monomer (B) is solid at 25 ° C.
(2) The maleimide monomer (B) is supplied to the reaction vessel in a solid state.
(3) Reaction when supplying the maleimide monomer (B) to the reaction vessel in a solid state
The temperature in a tank is 0 degreeC or more and 80 degrees C or less.
(4) Reaction when a polymerization monomer other than the maleimide monomer (B) is supplied to the reaction vessel
The temperature in the reaction tank is 0 ° C. or higher and 80 ° C. or lower.
(5) The acid value of the maleimide monomer (B) is 1.0 or less.
[2]
Furthermore, the manufacturing method of the methacrylic resin as described in said [1] which satisfy | fills the conditions of following (6).
(6) The maleimide monomer (B) has a particle size component content of 0.15 mm or less.
It is 0.7 mass% or less.
[3]
The method for producing a methacrylic resin according to [1] or [2] , wherein the maleimide monomer (B) is at least one selected from the group consisting of N-phenylmaleimide and N-cyclohexylmaleimide.
[4]
The method for producing a methacrylic resin according to any one of [1] to [3], wherein the polymerization step is performed by a suspension polymerization method.
[5]
The temperature in the reaction vessel when supplying monomer components 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). [1
] The manufacturing method of the methacrylic resin as described in any one of [4].
[6]
The method for producing a methacrylic resin according to any one of [1] to [5], wherein a content of a particle size component of 9.5 mm or more of the maleimide monomer (B) is 10% by mass or less. .
[7]
The method for producing a methacrylic resin according to any one of [1] to [6], wherein the maleimide monomer (B) has an average particle size of 0.2 mm to 9 mm.
[8]
In the polymerization step, the polymerization initiator is supplied to the reaction tank together with the methacrylic acid ester monomer (A) and the other vinyl monomer (C).
[7] The method for producing a methacrylic resin according to any one of [7].

Claims (10)

Methacrylic acid ester monomer (A): 50 to 99% by mass,
Maleimide monomer (B) 1-30% by mass,
And other vinyl monomer (C): having a polymerization step of copolymerizing 0 to 20% by mass in a reaction vessel,
A method for producing a methacrylic resin that satisfies the following conditions (1) to (3).
(1) The maleimide monomer (B) is solid at 25 ° C.
(2) The maleimide monomer (B) is supplied to the reaction vessel in a solid state.
(3) In the maleimide monomer (B), the content of a particle size component of 0.15 mm or less is 10% by mass 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-phenylmaleimide and N-cyclohexylmaleimide. The method for producing a methacrylic resin according to claim 1 or 2, wherein the polymerization step is performed by a suspension polymerization method. The temperature in the reaction tank when supplying the maleimide monomer (B) in a solid state to the reaction tank is 0 ° C or higher and 80 ° C or lower, according to any one of claims 1 to 3. A method for producing a methacrylic resin. The temperature in the reaction vessel when supplying monomer components 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
The manufacturing method of the methacrylic resin as described in any one of thru | or 4. The method for producing a methacrylic resin according to any one of claims 1 to 5, wherein a content of a particle size component of 9.5 mm or more of the maleimide monomer (B) is 10 mass% or less. The method for producing a methacrylic resin according to any one of claims 1 to 6, wherein the maleimide monomer (B) has an average particle size of 0.2 mm or more and 9 mm or less. In the said superposition | polymerization process, a polymerization initiator is supplied to the said reaction tank with the said methacrylic ester monomer (A) and the said other vinyl monomer (C). A method for producing a methacrylic resin according to claim 1. A methacrylic resin obtained by the method for producing a methacrylic resin according to any one of claims 1 to 8.   The molded object obtained by shape | molding the methacrylic resin of Claim 9.