JP5968368B2 - Methacrylic resin for injection molding - Google Patents

Description

The present invention relates to a methacrylic resin for injection molding .

Methacrylic resins represented by polymethyl methacrylate (PMMA) have high transparency, so optical materials, vehicle parts, building materials, lenses, household goods, OA equipment, lighting equipment, etc. Widely used in the field.
In particular, in recent years, the use for vehicle materials and optical materials such as light guide plates and liquid crystal display films has progressed. However, in the case of conventionally known methacrylic resins, there is a problem of insufficient solvent resistance, and molding processing is difficult. Applications that become difficult are increasing, and the molded body of methacrylic resin may cause cracks and crazes when brought into contact with an organic solvent, resulting in fatal defects.
In addition, when a large and thin molded product is injection-molded, the injection pressure is insufficient due to poor resin fluidity, and molding may not be possible, or distortion of the molded product may increase.
For this reason, there is a demand for a methacrylic resin having both solvent resistance and mechanical strength, while high fluidity that enables molding even at low injection pressure is desired.

Conventionally, as a method for improving the mechanical strength and moldability of a methacrylic resin, a method of imparting fluidity with a low molecular weight methacrylic resin and imparting mechanical strength with a high molecular weight or a micro-crosslinked structure is known. In relation to this, techniques for melting and mixing high molecular weight or low molecular weight methacrylic resins or expanding the molecular weight distribution using a branched structure have been reported (for example, see Patent Documents 1 to 3).
Furthermore, in Patent Document 4 below, the weight average molecular weight (Mw) fractionates the molecular weight distribution of a certain range of methacrylic resin, and the characteristics are improved by defining the ratio of the low molecular weight to the peak top (Mp). Techniques to be disclosed are disclosed.

On the other hand, in a methacrylic resin, a methacrylic resin composition in which a predetermined additive is mixed with the methacrylic resin, and further, in these molded articles, in particular, an application using an alcohol-based detergent, acid resistance, or alkaline cleaning ( For example, more solvent resistance is required in consideration of products around water.
Generally, as a method for improving the solvent resistance and mechanical strength of a methacrylic resin composition, a method of increasing the molecular weight of a base resin or adding a rubbery polymer or an inorganic filler is known. .
However, increasing the molecular weight of the base resin or adding a rubbery polymer reduces fluidity and makes melt molding difficult, and adding inorganic fillers or other pigments reduces toughness and processing. There arises a problem that the stability becomes unstable.

  Furthermore, a resin composition for artificial marble in which silica is added as a filler to an acrylic syrup resin with improved scratch resistance and impact resistance, and additives such as an internal release agent and a curing agent are added. Has also been proposed (see, for example, Patent Document 5).

Japanese Patent Publication No. 1-2865 JP-A-4-277545 Japanese Patent Laid-Open No. 9-207196 International Publication No. 2007/060891 Pamphlet JP 2002-161182 A

However, the methacrylic resin described in Patent Document 1 is a resin in which two methacrylic resins having different molecular weights are mixed, and fluidity is improved, but it does not satisfy both high fluidity and mechanical strength at the same time. .
Patent Document 2 describes a technique in which a methacrylic resin constituting a low molecular weight is copolymerized in a large amount with another vinyl monomer copolymerizable with methyl methacrylate. Both solvent resistance and fluidity are insufficient.
Furthermore, in the method for producing a slightly cross-linked methacrylic resin using a polyfunctional monomer described in Patent Document 3, it is very difficult to control the polyfunctional monomer, and if the amount of the polyfunctional monomer is too large, the mixing uniformity decreases. However, the appearance of the molded product is deteriorated. On the other hand, if the amount of the polyfunctional monomer is too small, there is a problem that there is no effect of improving fluidity and maintaining mechanical strength.
Furthermore, in the methacrylic resin obtained by the technique described in Patent Document 4, fluidity, mechanical strength, solvent resistance, and the like are good, but further solvent resistance and mechanical strength retention effect. Is required.

  In addition, the resin composition obtained by the technique described in Patent Document 5 is a composition for artificial marble although the scratch resistance and impact resistance of the molded body are improved by the addition of silica. There is a problem that it is not suitable for use.

  Therefore, in the present invention, a methacrylic resin, a methacrylic resin composition having good fluidity, high solvent resistance, heat resistance, impact resistance, and excellent processing stability, and in addition to the above characteristics An object of the present invention is to provide a molded article excellent in the stringing resistance, in particular, the stringing resistance at the time of welding at a high temperature.

As a result of intensive studies in order to solve the above-described problems of the prior art, the present inventors have a specific weight average molecular weight and a specific range of molecular weight distribution (Mw / Mn) as a methacrylic resin for melt molding. Has found that high solvent resistance, heat resistance and impact resistance can be obtained while maintaining high fluidity, and has led to the completion of the methacrylic resin of the present invention.
In addition, when a predetermined additive is mixed with the methacrylic resin, it can have functions such as solvent resistance, mechanical strength, molding fluidity, and coloring imparting while maintaining excellent processing stability. The inventor has completed the methacrylic resin composition of the present invention.
That is, the present invention is as follows.

[1]
Methacrylic acid ester monomer unit: 80-98.5 mass%,
At least one other vinyl monomer unit copolymerizable with the methacrylic acid ester monomer: 1.5 to 20% by mass;
A methacrylic resin containing
The weight average molecular weight (Mw) is 140000-250,000,
The methacrylic resin contains a weight average molecular weight component of 1/5 or less of the peak weight average molecular weight (Mp) obtained from the GPC elution curve,
The relationship between the weight average molecular weight (Mw) and the number average molecular weight (Mn) satisfies the following formula (i):
In the measurement of the twisting resistance for measuring the generation of the resin yarn when the hot plate having a surface temperature of 390 ° C. is pressed and released, the long yarn generation rate of 5 mm or more is 5% or less.
Methacrylic resin for injection molding .
3.2 ≦ Mw / Mn ≦ 5.5 (i)
[2]
In the area of the gel permeation chromatography (GPC) elution curve of the methacrylic resin,
Average composition ratio of other vinyl monomer units copolymerizable with the methacrylic acid ester monomer in the methacrylic resin having a weight average molecular weight component having a cumulative area area (%) of 0 to 2%. Mh (mass%),
Average composition ratio Ml of other vinyl monomer units copolymerizable with the methacrylic acid ester monomer in a methacrylic resin having a weight average molecular weight component having a cumulative area area (%) of 98 to 100% ( Mass%),
The methacrylic resin for injection molding according to the above [1], which has a relationship represented by the following formula (ii).
(Mh−0.8) ≧ Ml ≧ 0 (ii)
[3]
In the area of the gel permeation chromatography (GPC) elution curve of the methacrylic resin,
Average composition ratio of other vinyl monomer units copolymerizable with the methacrylic acid ester monomer in the methacrylic resin having a weight average molecular weight component having a cumulative area area (%) of 0 to 2%. Mh (mass%),
In the methacrylic resin having a weight average molecular weight component having a cumulative area area (%) of 98 to 100%, other vinyl monomer units copolymerizable with the methacrylic acid ester monomer,
Average composition ratio Ml (mass%),
Is a methacrylic resin for injection molding according to the above [1] or [2], which has the relationship of the following formula (iii).
8 ≧ (Mh−2) ≧ Ml ≧ 0 (iii)

  According to the present invention, the methacrylic resin for melt molding has good molding fluidity, is suitable for various melt molding, has high solvent resistance, heat resistance, impact resistance, and excellent processing stability. In addition to the resin, the methacrylic resin composition for melt molding, and the above-mentioned properties, a molded article having excellent stringing resistance, particularly stringing resistance at the time of welding at a high temperature can be obtained.

It is a figure which shows an example of the accumulation area area on the GPC (gel permeation chromatography) elution curve measurement graph of methacrylic resin. It is a figure which shows the accumulation area area in the predetermined elution time on a GPC elution curve measurement graph. It is the schematic which shows the position of 0-2% of accumulation area areas, and 98-100% of accumulation area areas on a GPC elution curve measurement graph. It is a schematic explanatory drawing of the solvent resistance test by a cantilever method.

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. Further, the structural unit constituting the polymer may be referred to as “˜monomer unit”.

[Methacrylic resin for melt molding]
The methacrylic resin for melt molding of the present embodiment (hereinafter sometimes simply referred to as methacrylic resin) is a methacrylic acid ester monomer unit: 80 to 98.5% by mass and the methacrylic acid ester monomer. And having at least one other vinyl monomer unit copolymerizable to 1.5 to 20% by mass and having a weight average molecular weight (Mw) of 140000 to 250,000, obtained from the elution curve of GPC The weight average molecular weight component of 1/5 or less of the peak weight average molecular weight (Mp) is contained in the range of 20% to 40%, and the relationship between the weight average molecular weight (Mw) and the number average molecular weight (Mn) is as follows (i ) Methacrylic resin for melt molding that satisfies the formula.
3.0 ≦ Mw / Mn ≦ 5.5 (i)

(Methacrylic acid ester monomer)
The methacrylic acid ester monomer constituting the methacrylic resin of the present embodiment is not particularly limited as long as the effects of the present invention can be achieved, but a preferred example is a single monomer represented by the following general formula (1). A monomer is mentioned.

In the 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 of the formula (1) include butyl methacrylate, ethyl methacrylate, methyl methacrylate, propyl methacrylate, isopropyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, methacrylic acid (2- Ethyl hexyl), methacrylic acid (t-butylcyclohexyl), benzyl methacrylate, methacrylic acid (2,2,2-trifluoroethyl) and the like, and a typical one is methyl methacrylate.
The said methacrylic acid ester monomer may be used individually by 1 type, or may be used in combination of 2 or more types.

(Other vinyl monomers that can be copolymerized with methacrylate monomers)
As another vinyl monomer copolymerizable with the above-mentioned methacrylic acid ester monomer constituting the methacrylic resin of this embodiment, an acrylate monomer represented by the following general formula (2) is used. Can be mentioned.

In said formula (2), R < ₃ > is a hydrogen atom and R < ₄ > is a C1-C18 alkyl group.

  Examples of the acrylate monomer represented by the general formula (2) include α, β-unsaturated acids such as acrylic acid and methacrylic acid, maleic acid, fumaric acid, itaconic acid, cinnamic acid and the like. Saturated divalent carboxylic acids and their alkyl esters; styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, 3,4-dimethylstyrene Styrene monomers such as 1,5-dimethylstyrene, p-ethylstyrene, m-ethylstyrene, о-ethylstyrene, p-tert-butylstyrene, isopropenyl benzene (α-methylstyrene); 1-vinyl Naphthalene, 2-vinylnaphthalene, 1,1-diphenylethylene, isopropenyltoluene, isopropenylethylbenzene Aromatic vinyl compounds such as isopropenyl propyl benzene, isopropenyl butyl benzene, isopropenyl pentyl benzene, isopropenyl hexyl benzene and isopropenyl octyl benzene; vinyl cyanide compounds such as acrylonitrile and methacrylonitrile; maleic anhydride, itaconic anhydride Unsaturated carboxylic anhydrides such as acids, maleimides, N-substituted maleimides such as N-methylmaleimide, N-ethylmaleimide, N-phenylmaleimide, N-cyclohexylmaleimide, and amides such as acrylamide and methacrylamide; Ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, etc. A product obtained by esterifying both hydroxyl groups of ethylene glycol or its oligomer with acrylic acid or methacrylic acid; the hydroxyl groups of two alcohols such as neopentyl glycol di (meth) acrylate and di (meth) acrylate are acrylic acid or methacrylic acid Esterified with polyhydric alcohol derivatives such as trimethylolpropane and pentaerythritol esterified with acrylic acid or methacrylic acid; and polyfunctional monomers such as divinylbenzene.

In the methacrylic resin of this embodiment, from the viewpoint of improving weather resistance, heat resistance, fluidity, and thermal stability, the other vinyl monomer copolymerizable with the methacrylic acid ester monomer is methyl acrylate. Ethyl acrylate, n-propyl acrylate, n-butyl acrylate, sec-butyl acrylate, 2-ethylhexyl acrylate and the like are preferably used.
In particular, methyl acrylate, ethyl acrylate, and n-butyl acrylate are preferable, and methyl acrylate is more preferable because it is easily available.

  In the methacrylic resin of this embodiment, for the purpose of improving properties such as heat resistance, optical properties, processability, etc., a vinyl monomer other than the vinyl monomers exemplified above is appropriately added and copolymerized. You may let them.

  The said vinyl monomer may be used individually by 1 type, and may be used in combination of 2 or more types.

The content of other vinyl monomer units that can be copolymerized with the above-described methacrylic acid ester monomer constituting the methacrylic resin of the present embodiment is 1.5 to 5 in the methacrylic resin of the present embodiment. 20% by mass.
In order to improve fluidity and heat resistance, 1.5% by mass or more is necessary. Moreover, in order to improve heat resistance, it is necessary to be 20 mass% or less.
Preferably it is 1.5-15 mass%, More preferably, it is 2-12 mass%, More preferably, it is 3-10 mass%.

(Molecular weight and molecular weight distribution of methacrylic resin for melt molding)
The molecular weight and molecular weight distribution of the methacrylic resin of this embodiment and the methacrylic resin that is the component (A) constituting the methacrylic resin composition described later will be described.
As for the molecular weight of the methacrylic resin, the weight average molecular weight (Mw) measured by GPC (gel permeation chromatography) is 140000-250,000.
In order to make the mechanical strength and solvent resistance of the molded product obtained by molding the methacrylic resin or methacrylic resin composition of the present embodiment practically good, the weight average molecular weight (Mw) is 140000 or more. is necessary.
Further, in order for the methacrylic resin or the methacrylic resin composition to exhibit good fluidity, the weight average molecular weight (Mw) needs to be 250,000 or less.
Furthermore, when the weight average molecular weight of the methacrylic resin is within the above range, excellent moldability can be obtained.
Considering the balance of fluidity, mechanical strength, and solvent resistance, the weight average molecular weight (Mw) of the methacrylic resin of this embodiment is preferably 140000 to 230,000, and more preferably 150,000 to 210000.

The molecular weight distribution (weight average molecular weight / number average molecular weight: Mw / Mn) of the methacrylic resin of this embodiment and the methacrylic resin (A) constituting the methacrylic resin composition described later impairs fluidity. In order to achieve high solvent resistance that has never been achieved without further, in order to maintain the processing stability in the methacrylic resin composition for melt molding containing the additive (B) described later, The conditions shown in the following formula (i) shall be satisfied.
3.0 ≦ Mw / Mn ≦ 5.5 (i)
When the molecular weight distribution satisfies the condition shown in the above formula (i), the processing stability is drastically improved.
For example, when Mw ≧ 140000, when Mw / Mn <3.0, or Mw / Mn> 5.5, the processing stability in the methacrylic resin composition containing the additive as the component (B), The balance between fluidity and solvent resistance tends to deteriorate. 3.2 ≦ Mw / Mn ≦ 5.2 is more preferable, since processing stability, balance between fluidity and solvent resistance, and stringing resistance are further improved, and 3.5 ≦ Mw / Mn ≦ 5.0. Is more preferable.

As described above, the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the methacrylic resin of this embodiment can be measured by gel permeation chromatography (GPC). Prepare a calibration curve from the elution time and the weight average molecular weight in advance using a standard methacrylic resin that is known as a reagent with a known monodispersed weight average molecular weight and an analytical gel column that elutes the high molecular weight component first. Based on the calibration curve obtained in this way, the molecular weight weight average molecular weight (Mw) and number average molecular weight (Mn) of the methacrylic resin to be measured can be determined, and the molecular weight distribution can be calculated.
The number average molecular weight is a simple average molecular weight per molecule, and is defined by the total weight of the system / number of molecules in the system.
The weight average molecular weight is defined as the average molecular weight by weight fraction.

The methacrylic resin of the present embodiment and the methacrylic resin that is the component (A) constituting the methacrylic resin composition described later are the methacrylic resin from the balance of fluidity, heat resistance, weather resistance, and solvent resistance. The amount of the weight average molecular weight component of 1/5 or less of the peak weight average molecular weight (Mp) present in is assumed to be 20 to 40%, and preferably 20 to 30%.
Good fluidity is obtained when the abundance of the weight average molecular weight component of 1/5 or less of the peak weight average molecular weight (Mp) present in the methacrylic resin is 20% or more. If it is within 40%, the solvent resistance is not adversely affected.
Further, the methacrylic resin component having a weight average molecular weight of 500 or less is preferably as small as possible in order to prevent occurrence of a foam-like appearance defect called silver during molding.
In addition, the said peak weight average molecular weight (Mp) points out the weight average molecular weight which shows a peak in a GPC elution curve.
When there are a plurality of peaks in the GPC elution curve, the weight average molecular weight at the peak indicated by the weight molecular weight having the largest abundance is defined as the peak weight average molecular weight (Mp).

(Composition ratio of other vinyl monomers copolymerizable with methacrylic acid ester monomers in high molecular weight components and low molecular weight components of methacrylic resins for melt molding)
Other vinyls copolymerizable with the methacrylic acid ester monomer described above, which are contained in the methacrylic resin of this embodiment and the methacrylic resin that is the component (A) constituting the methacrylic resin composition described later. As for the monomer, it is preferable from the viewpoint of stability during polymerization that the composition ratio in the high molecular weight component of the methacrylic resin is larger than the composition ratio in the low molecular weight component.
The composition ratio of the other vinyl monomer copolymerizable with the methacrylic acid ester monomer in the high molecular weight component and the low molecular weight component of the methacrylic resin can be calculated using the area of the GPC elution curve.
The area area in the GPC elution curve means, for example, a hatched portion in the GPC elution curve shown in FIG.
A specific method of determination will be described below.

First, with respect to the GPC elution curve obtained from the elution time obtained by GPC measurement and the detection intensity by RI (differential refraction detector), the point A and the point where the baseline automatically drawn by the measuring instrument and the GPC elution curve intersect Define B.
Point A is a point where the GPC elution curve at the beginning of the elution time and the baseline intersect.
Point B is, as a rule, a position where the weight average molecular weight is 500 or more and the baseline and the GPC elution curve intersect.
If the weight average molecular weight does not intersect within the range of 500 or more, the value of RI detection intensity at the elution time when the weight average molecular weight is 500 is defined as point B.
A hatched portion surrounded by the GPC elution curve between the points A and B and the line segment AB is an area in the GPC elution curve.
This area is the area of the GPC elution curve.
By using the column eluted from the high molecular weight component, the high molecular weight component is observed at the beginning of the elution time, and the low molecular weight component is observed at the end of the elution time.

The cumulative area area (%) of the area area in the GPC elution curve is point 0 shown in FIG. 2 being 0% which is the standard of the cumulative area area (%), and the detection corresponding to each elution time is directed toward the end of the elution time. The view is that the intensity accumulates and an area area in the GPC elution curve is formed.
A specific example of the accumulated area area is shown in FIG.
In FIG. 2, a point on the baseline at a certain elution time is a point X, and a point on the GPC elution curve is a point Y.
The ratio of the area surrounded by the curve AY, the line segment AX, and the line segment XY to the entire area area in the GPC elution curve is defined as a cumulative area area (%) at a certain elution time X.
Let Mh (mass%) be the average composition ratio of other vinyl monomer units copolymerizable with a methacrylic ester in a methacrylic resin having a high molecular weight component in a cumulative area of 0 to 2%.
On the other hand, the average composition ratio of other vinyl monomer units copolymerizable with a methacrylic acid ester in a methacrylic resin having a cumulative area area of 98 to 100%, that is, a low molecular weight component is defined as Ml (mass%).
FIG. 3 shows a schematic diagram of positions on the measurement graph of the accumulated area area of 0 to 2% and 98 to 100%.

Average composition ratio Mh (mass%) of other vinyl monomer units copolymerizable with methacrylic acid ester in methacrylic resin having a high molecular weight component in a cumulative area area of 0 to 2%, cumulative area area 98 The average composition ratio Ml (% by mass) of other vinyl monomer units copolymerizable with methacrylic acid esters in a methacrylic resin having a low molecular weight component of ˜100% is the elution obtained from GPC Based on the time, it can be obtained by continuously collecting several times or several tens of times depending on the column size.
Specifically, the composition of the collected sample may be analyzed by a known pyrolysis gas chromatography (GC) method.
It is preferable that Mh (mass%) and Ml (mass%) satisfy the following formula (ii).
(Mh−0.8) ≧ Ml ≧ 0 (ii)
This indicates that the high molecular weight component has a higher average composition of 0.8% by mass or more of other vinyl monomer units copolymerizable with the methacrylic acid ester than the low molecular weight component. Furthermore, the low molecular weight component indicates that other vinyl monomers are not necessarily copolymerized.
The difference between Mh (mass%) and Ml (mass%) is preferably 2 mass% or more for the effect of improving fluidity.
More preferably, it is 2.5 mass%, More preferably, the following formula (iii) is satisfied.
8 ≧ (Mh−2) ≧ Ml ≧ 0 (iii)

As shown in the formula (iii), an average composition ratio of other vinyl monomer units copolymerizable with a methacrylic acid ester in a methacrylic resin having a high molecular weight component in a cumulative area area of 0 to 2% ( Mh) is 2% by mass or more and 10% by mass or less, while maintaining the effect of improving heat resistance, the effect of reducing the probability of cracks and distortion occurring in the molded body in the environmental test, and the mechanical strength. The effect of improving the fluidity, and further the effect of stringing resistance in hot plate welding, particularly the stringing resistance during high temperature welding are obtained.
From the viewpoint of heat resistance, Mh is more preferably 6 ≧ Mh ≧ 2, and even more preferably 4 ≧ Mh ≧ 2.

[Method for producing methacrylic resin for melt molding]
In the method for producing a methacrylic resin of this embodiment, first, in the first-stage polymerization, a polymer (I) having a weight average molecular weight of 5000 to 50000 using a raw material mixture containing a methacrylic acid ester monomer. ) Is produced in an amount of 5 to 45% by mass based on the entire methacrylic resin.
Next, the inside of the polymerization system is maintained at a temperature higher than the first stage polymerization temperature for a certain period of time.
Thereafter, in the presence of the polymer (I), a raw material mixture containing a methacrylic acid ester is further added and polymerized, and the polymer (II) having a weight average molecular weight of 150,000 to 350,000 is added to the entire methacrylic resin. On the other hand, 95-55 mass% is manufactured.
The ratio of the polymer (I) to the polymer (II) is as described above from the viewpoint of improving the polymerization stability at the time of production and the fluidity and the mechanical strength of the resin molded product when used as a methacrylic resin. preferable.
Considering the balance of polymerization stability, fluidity and mechanical strength of the molded product, the ratio of polymer (I) / (II) is preferably 10 to 40% by mass / 90 to 60% by mass, more preferably 15 to It is 35 mass% / 85-65 mass%, More preferably, it is 20-35 mass% / 80-65 mass%.
In addition, as a method for polymerizing the polymer (I) and the polymer (II) as described above, any of bulk polymerization, solution polymerization, suspension polymerization or emulsion polymerization is preferable. More preferred are bulk polymerization, solution polymerization and suspension polymerization, and further preferred is suspension polymerization.

(First stage: Production process of polymer (I))
In the method for producing a methacrylic resin of the present embodiment, first, in the first stage polymerization step, a polymer (I) is produced from a raw material mixture containing a methacrylic acid ester monomer.
As the raw material mixture, a methacrylic acid ester monomer or another vinyl monomer copolymerizable with a methacrylic acid ester monomer and at least one methacrylic acid ester can be used.
The raw material of the polymer (I) is a monomer composed of 80 to 100% by mass of a methacrylic acid ester monomer and at least one of other vinyl monomers copolymerizable with the methacrylic acid ester. % Is preferred.
The amount of other vinyl monomers copolymerizable with the methacrylic acid ester is preferably small, and may not be used.
In addition, the molecular weight of the polymer (I) is 5000 to 50000 in terms of the weight average weight measured by GPC from the viewpoint of suppression of defects such as silver during molding, polymerization stability, fluidity, and string resistance. It is preferable to set it as 10000-45000, and 20000-40000 is further more preferable.

(Temperature raising and temperature holding process)
After performing the polymerization step of the first-stage polymer (I), the temperature in the polymerization system is raised to a temperature higher than the first-stage polymerization temperature and held for a certain period of time.
The temperature to be raised is preferably 5 ° C. or more higher than the polymerization temperature of the polymer (I), more preferably 7 ° C. or more, and further preferably 10 ° C. or more.
Furthermore, the holding time is preferably 10 minutes or more and 180 minutes or less, more preferably 15 minutes or more and 150 minutes or less.
In this way, after the first stage polymerization step, by raising the temperature and holding, not only the polymerization is completed, but also the unreacted monomer, initiator, chain transfer agent, etc. are removed or deactivated. And no adverse effect on the second stage polymerization. As a result, the target weight average molecular weight can be obtained. As a result, a polymer having a target weight average molecular weight is obtained.
In this case, the polymerization of the raw material mixture of the polymer (II) may be partially started before the polymerization of the polymer (I) is completed, but once cured (in this case, the inside of the system is polymerized). It is preferable to add the raw material mixture of the polymer (II) after the polymerization of the polymer (I) is completed by maintaining the temperature higher than the temperature.

(Second stage: Production process of polymer (II))
As described above, after being maintained at a predetermined temperature, as a second or subsequent polymerization step, a raw material mixture containing a methacrylic acid ester monomer in the presence of the polymer (I), that is, a methacrylic acid ester monomer Alternatively, a combination of a methacrylic acid ester monomer and another vinyl monomer copolymerizable with the methacrylic acid ester is added, and the weight average molecular weight measured by gel permeation chromatography is 150,000 to 350,000. The polymer (II) is produced in an amount of 95 to 55% by mass with respect to the entire methacrylic resin.
The raw material mixture of the polymer (II) is a monomer 0 composed of 80 to 99.5% by mass of a methacrylic acid ester monomer and at least one other vinyl monomer copolymerizable with the methacrylic acid ester. It is preferably composed of 5 to 20% by mass.
From the viewpoint of the fluidity of the methacrylic resin or the methacrylic resin composition, the solvent resistance of these molded articles, and the stringing resistance, the polymer (II) has a weight average weight measured by GPC of 150,000 to 350,000. It is more preferable that it is 150,000-320,000, and it is further more preferable that it is 150,000-300000.

As the methacrylic acid ester monomer used in the multistage polymerization described above, the same or different ones may be used in the polymer (I) and the polymer (II).
In addition, as the vinyl monomer copolymerizable with the methacrylic acid ester monomer, the same or different ones may be used in the polymer (I) and the polymer (II).
In addition, the multistage polymerization method as described above makes it easy to control the composition of each of the polymer (I) and the polymer (II), suppresses a temperature rise due to polymerization heat generation during polymerization, and stabilizes the viscosity in the system. .

(Polymerization temperature)
The polymerization temperature of the polymer (I) and the polymer (II) may be produced by appropriately selecting an optimal polymerization temperature according to the polymerization method, but is preferably 50 ° C. or higher and 100 ° C. or lower, more preferably It is 60 degreeC or more and 90 degrees C or less.
The polymerization temperature of the polymer (I) and the polymer (II) may be the same or different.

In order to control the composition ratios Ml and Mh within the above-mentioned range, other vinyl monomers copolymerizable with the methacrylic acid ester monomer added during the first and second and subsequent polymerizations are used. Adjust the amount.
Specifically, in order to achieve the conditions of the above-described relational expressions (ii) and (iii), the composition ratio of other vinyl monomers copolymerizable with the methacrylic acid ester of the polymer (I) is expressed as Mal ( Mass%), and when the composition ratio of other vinyl monomers copolymerizable with the methacrylic acid ester of the polymer (II) is Mah (mass%), the relationship of the following formula (a) is obtained from the polymerization stability. It is preferable to adjust the raw materials so as to hold.
Mah ≧ Mal ≧ 0 (a)

When the polymer (II) having a high molecular weight contains a larger amount of other vinyl monomers copolymerizable with methacrylic acid esters as a composition ratio, not only can the polymerization stability be improved, but also heat resistance and This is preferable because the fluidity can be improved while maintaining the mechanical strength.
More preferably, the relationship of the following formula (b) is established.
(Mah−0.8) ≧ Mal ≧ 0 (b)
When the methacrylic resin is required to have a good balance between solvent resistance and fluidity while maintaining heat resistance, it is preferably within the range of the following formula (c).
8 ≧ (Mah−2) ≧ Mal ≧ 0 (c)

(Polymerization initiator)
When producing the methacrylic resin as the component (A) constituting the methacrylic resin of this embodiment and the methacrylic resin composition described later, a polymerization initiator may be used.
As the polymerization initiator, when performing radical polymerization, for example, di-t-butyl peroxide, lauroyl peroxide, stearyl peroxide, benzoyl peroxide, t-butyl peroxyneodecanate, t-butyl peroxypi Valate, dilauroyl peroxide, dicumyl peroxide, t-butylperoxy-2-ethylhexanoate, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1 -Organic peroxides such as bis (t-butylperoxy) cyclohexane, azobisisobutyronitrile, azobisisovaleronitrile, 1,1-azobis (1-cyclohexanecarbonitrile), 2,2'-azobis -4-methoxy-2,4-azobisisobutyronitrile, 2,2'-a Can be exemplified bis-2,4-dimethylvaleronitrile, 2,2'-azobis-2-methyl butyronitrile general radical polymerization initiator azo such as nitrile.
These may be used alone or in combination of two or more.
A combination of these radical 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. And can be selected as appropriate.

  When polymerizing the methacrylic resin of this embodiment, when selecting a bulk polymerization method, a cast polymerization method, or a suspension polymerization method, from the viewpoint of preventing coloring of the target methacrylic resin, as a polymerization initiator For example, peroxy initiators such as lauroyl peroxide, decanoyl peroxide, and t-butylperoxy-2-ethylhexanoate are preferable, and lauroyl peroxide is preferably used.

In addition, when polymerizing the methacrylic resin of the present embodiment by selecting a solution polymerization method at a high temperature of 90 ° C. or higher, the 10-hour half-life temperature is 80 ° C. or higher, and the organic solvent used It is preferable to use a soluble peroxide, an azobis initiator, or the like.
Specifically, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, cyclohexane peroxide, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, , 1-azobis (1-cyclohexanecarbonitrile), 2- (carbamoylazo) isobutyronitrile, and the like.

(Molecular weight control)
When producing the methacrylic resin of the present embodiment and the methacrylic resin that is the component (A) constituting the methacrylic resin composition described later, the molecular weight of the methacrylic resin is within a range that does not impair the purpose of the present invention. Control can be performed.
For example, in the polymerization process of the polymers (I) and (II), chain transfer agents such as alkyl mercaptans, dimethylacetamide, dimethylformamide, triethylamine, iniferters such as dithiocarbamates, triphenylmethylazobenzene, tetraphenylethane derivatives, etc. The molecular weight can be controlled by using. Moreover, it is possible to adjust molecular weight by adjusting these addition amounts.
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-tetradecyl mercaptan, n-octadecyl mercaptan, Examples include 2-ethylhexyl thioglycolate, ethylene glycol dithioglycolate, trimethylolpropane tris (thioglycolate), pentaerythritol tetrakis (thioglycolate), and the like.

These can be added as appropriate according to the molecular weight of the methacrylic resin to be obtained. Used in the range of parts.
Examples of 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.
These molecular weight control methods may use only one type of method, or may use two or more types in combination.

[Other components that can be mixed with methacrylic resin for melt molding]
<Other resins>
The methacrylic resin of the present embodiment and the methacrylic resin that is the component (A) constituting the methacrylic resin composition of the present embodiment, which will be described later, are used in combination with a conventionally known resin as long as melt molding is possible. be able to.
The resin to be used is not particularly limited, and known curable resins and thermoplastic resins are preferably used.
Examples of the thermoplastic resin include polypropylene resin, polyethylene resin, polystyrene resin, syndiotactic polystyrene resin, ABS resin, methacrylic resin, AS resin, BAAS resin, MBS resin, AAS resin, raw resin, and the like. Degradable resin, Polycarbonate-ABS resin alloy, Polybutylene terephthalate, Polyethylene terephthalate, Polypropylene terephthalate, Polytrimethylene terephthalate, Polyethylene naphthalate and other polyalkylene arylate resins, polyamide resins, polyphenylene ether resins, polyphenylene sulfide resins And phenolic resins.
In particular, AS resin and BAAS resin are preferable for improving fluidity, ABS resin and MBS resin are 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 achieve the effect of improving flame retardancy.
Examples of the curable resin include unsaturated polyester resin, vinyl ester resin, diallyl phthalate resin, epoxy resin, cyanate resin, xylene resin, triazine resin, urea resin, melamine resin, benzoguanamine resin, urethane resin, oxetane resin, Examples include ketone resins, alkyd resins, furan resins, styrylpyridine resins, silicone resins, and synthetic rubbers.
These resins may be used alone or in combination of two or more.

<Additives that can be mixed with methacrylic resins for melt molding>
In order to impart predetermined various characteristics such as rigidity and dimensional stability to the methacrylic resin for melt molding of the present embodiment, various additives may be mixed within a range not impairing the effects of the present invention.
Examples of additives include plasticizers such as phthalic acid esters, fatty acid esters, trimellitic acid esters, phosphate esters, and polyesters, higher fatty acids, higher fatty acid esters, higher fatty acid mono-, di-, or triglycerides. Mold release agents such as polyethers; antistatic agents such as polyethers, polyetheresters, polyetheresteramides, alkylsulfonates, alkylbenzenesulfonates; antioxidants, UV absorbers, heat stabilizers, Stabilizers such as light stabilizers; flame retardants, flame retardant aids, curing agents, curing accelerators, conductivity imparting agents, stress relaxation agents, crystallization accelerators, hydrolysis inhibitors, lubricants, impact imparting agents, slides Mobility improver, compatibilizer, nucleating agent, reinforcing agent, reinforcing agent, flow modifier, dye, sensitizer, coloring pigment, rubber polymer, thickener, antisettling agent, sagging inhibitor, filling , Defoamers, coupling agents, rust inhibitors, antibacterial and antifungal, antifouling agent, conductive polymers.
Examples of the flame retardant include cyclic nitrogen compounds, phosphorus-based flame retardants, silicon, caged silsesquioxane or its partial cleavage structure, and silica.

As said heat stabilizer, antioxidants, such as a hindered phenolic antioxidant and a phosphorus processing stabilizer, etc. are mentioned, for example, A hindered phenolic antioxidant is preferable.
Specifically, pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, thiodiethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) ) Propionate, octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, N, N′-hexane-1,6-diylbis [3- (3,5-di-tert-butyl) -4-hydroxyphenylpropionamide, 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 (oxy) Ethylene) 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, and pentaerythritol terakis [3- (3,5-di-ter - butyl-4-hydroxyphenyl) propionate are preferred.

Examples of the ultraviolet absorber include benzotriazole compounds, benzotriazine compounds, benzoate compounds, benzophenone compounds, oxybenzophenone compounds, phenol compounds, oxazole compounds, malonic acid ester compounds, and cyanoacrylate compounds. Lactone-based compounds, salicylic acid ester-based compounds, benzoxazinone-based compounds, and the like, and preferred are benzotriazole-based compounds and benzotriazine-based compounds.
These may be used alone or in combination of two or more.
Moreover, when adding an ultraviolet absorber, from the viewpoint of molding processability, the vapor pressure (P) at 20 ° C. is preferably 1.0 × 10 ⁻⁴ Pa or less, more preferably 1.0 × 10 ^{−. 6} Pa or less, more preferably 1.0 × 10 ⁻⁸ Pa or less.
“Excellent molding processability” means, for example, that the ultraviolet absorber hardly adheres to the roll during film formation.
If it adheres to the roll, for example, it may adhere to the surface of the molded body and deteriorate the appearance and optical properties, so it is not preferable when the molded body is used as an optical material.
Moreover, it is preferable that melting | fusing point (Tm) of an ultraviolet absorber is 80 degreeC or more, More preferably, it is 100 degreeC or more, More preferably, it is 130 degreeC or more, More preferably, it is 160 degreeC or more.
The UV absorber preferably has a weight loss rate of 50% or less, more preferably 30% or less, and even more preferably 15% or less when the temperature is increased from 23 ° C. to 260 ° C. at a rate of 20 ° C./min. Even more preferably, it is 10% or less, and still more preferably 5% or less.

The kneading method for mixing the methacrylic resin for melt molding with the above-described various additives and other predetermined resins is not particularly limited.
For example, it can be kneaded and produced using a kneader such as an extruder, a heating roll, a kneader, a roller mixer, a Banbury mixer and the like. In particular, kneading with an extruder is preferable in terms of productivity.
The kneading temperature may be in accordance with a preferred processing temperature of the methacrylic resin for melt molding of the present embodiment or a predetermined other resin to be mixed. It is.

[Molded product of methacrylic resin for melt molding]
A desired molded article can be obtained by molding the methacrylic resin of this embodiment described above.
The methacrylic resin of this embodiment can be molded by a known method of molding in a molten state such as injection molding, sheet molding, blow molding, injection blow molding, inflation molding, T-die molding, press molding, extrusion molding, etc. Secondary processing molding methods such as pressure forming and vacuum forming can also be used.
In particular, since the methacrylic resin of this embodiment is excellent in fluidity during melt molding, it is preferably molded by injection molding, and is particularly suitable for high pressure and high speed melt molding.
As an example, a method of kneading a predetermined material using a kneader such as a heating roll, a kneader, a Banbury mixer, an extruder, cooling, pulverizing, and further performing molding by transfer molding, injection molding, compression molding, or the like is an example. Can be mentioned.
The order of mixing the components is not particularly limited as long as the effect of the present invention can be achieved.
The curing method after mixing the thermosetting resin and melt-molding is different depending on the curing agent to be used, but is not particularly limited. Examples include thermal curing, light curing, UV curing, pressure curing, moisture curing, and the like.

[Methacrylic resin composition for melt molding]
The methacrylic resin composition of the present embodiment includes the component (A): a methacrylic resin and a component (B) described later: a powder of resin particles, organic rubber particles, an inorganic filler, and a colorant. Contains at least one additive selected.
Moreover, the methacrylic resin composition of this embodiment may contain predetermined other resins and various additives that can be mixed with the methacrylic resin described above.

((A) component)
The methacrylic resin of this embodiment described above is used.
((B) component: additive)
(B): At least one additive selected from the group consisting of powder of resin particles, organic rubber particles, inorganic filler, and colorant will be described.

<Powder of resin particles>
In particular, it is preferable to use a resin particle powder having a heat resistant temperature of 250 ° C. or higher.
Here, the “heat-resistant temperature” is a lower limit temperature (thermal decomposition temperature) that chemically denatures by a decomposition reaction or the like when continuously used at the temperature.
By using a heat-resistant temperature of 250 ° C. or more, the shape does not change even at high temperatures during the preparation of methacrylic resin compositions and during molding, and the impact resistance and chemical crack resistance of the molded body are improved. Can be made.
Examples of the resin particle powder include particles made of PTFE (polytetrafluoroethylene) resin.
Polytetrafluoroethylene is typically a tetrafluoroethylene homopolymer, but in addition to tetrafluoroethylene as a monomer component, a small amount of a modifier such as perfluoroolefin, hydrofluoroolefin, perfluorovinyl ether, etc. It may be polymerized.
As the PTFE resin, a baked one is typically used, and its melting point is, for example, 300 ° C. or higher.
Further, by adding PTFE resin particles, it is possible to suppress dimensional deformation due to water absorption of the methacrylic resin composition due to the water repellent effect of the fluorine group.

<Organic rubber particles>
The organic rubber particles are not particularly limited, and for example, rubber particles having a multilayer structure such as general butadiene-based ABS rubber, acrylic-based, polyolefin-based, silicon-based, and fluorine rubber can be used.
In particular, particles having a multilayer structure of three or more layers are preferable, and acrylic rubber particles having a multilayer structure of three or more layers are more preferable from the viewpoint of compatibility with the methacrylic resin (A).
By using rubber particles having a multilayer structure of three layers or more, heat deterioration during molding processing and deformation of organic rubber particles due to heating are suppressed, and heat resistance and thermal deformation of the molded body tend to be suppressed. It is in.
The organic rubber particles having a multilayer structure of three or more layers are rubber particles having a multilayer structure in which a soft layer made of a rubber-like polymer and a hard layer made of a glass-like polymer are laminated, and preferably a hard layer from the inside. -Particles having a three-layer structure formed in the order of soft layer-hard layer.
By having a hard layer in the innermost layer and the outermost layer, deformation of particles tends to be suppressed, and by having a soft component in the central layer, good toughness tends to be imparted.

For example, the copolymer forming the innermost layer (bi) of acrylic organic rubber particles is preferably a methyl methacrylate monomer unit, an acrylate monomer unit copolymerizable therewith, an aromatic A group composed of an aromatic vinyl compound monomer unit and a copolymerizable polyfunctional monomer unit can be selected.
Although it does not specifically limit as an acrylate ester monomer in the copolymer which forms the innermost layer (bi) of the said acrylic organic rubber particle, Methyl acrylate, ethyl acrylate, n-acrylic acid n- Examples thereof include butyl, i-butyl acrylate, 2-hexyl acrylate, and the like, and preferably n-butyl acrylate and 2-hexyl acrylate.
As the aromatic vinyl compound monomer, the same monomers as those used in the methacrylic resin (A) can be used, but preferably styrene or a derivative thereof is used.
The copolymerizable polyfunctional monomer is not particularly limited, but ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1,4-butanediol. Examples include di (meth) acrylate, allyl (meth) acrylate, triallyl isocyanurate, diallyl maleate, and divinylbenzene.
These may be used alone or in combination of two or more. Of these compounds, allyl (meth) acrylate is particularly preferred.

The copolymer forming the central layer (b-ii) of the acrylic organic rubber particles is preferably a copolymer exhibiting soft rubber elasticity from the viewpoint of imparting excellent toughness to the methacrylic resin. , An acrylic ester unit, an aromatic vinyl compound monomer unit copolymerizable with an acrylic ester, a polyfunctional grafting agent or a polyfunctional crosslinking agent can be selected.
The acrylic ester constituting the central layer (b-ii) is not particularly limited, and examples thereof include methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, and the like. May be used alone or in combination. In particular, n-butyl acrylate and 2-hexyl acrylate are more preferable, and n-butyl acrylate and 2-hexyl acrylate are more preferable.
Further, styrene or a derivative thereof is preferably used as an aromatic vinyl compound monomer copolymerized with an acrylate ester.
As the polyfunctional grafting agent, the same copolymerizable polyfunctional monomer used in the innermost layer (bi) can be used, and the content thereof is 0.1% by mass or more and 5% by mass. % Or less is preferable because it has a good crosslinking effect, is moderately crosslinked and has a large rubber elasticity effect.
Moreover, as a polyfunctional crosslinking agent, generally known crosslinking agents such as divinyl compounds, diallyl compounds, diacrylic compounds, and dimethacrylic compounds can be used, but polyethylene glycol diacrylate (molecular weight 200 to 600) is preferably used. It is done. The polyfunctional crosslinking agent used here is used for producing a crosslinked structure at the time of polymerization of the central layer (b-ii) and exhibiting an effect as an elastic body. However, if the above-mentioned polyfunctional grafting agent is used during the polymerization of the soft layer, a cross-linked structure of the soft layer is generated to some extent. b-ii) The proportion used during the polymerization is 0 to 5% by mass. If the ratio of the unit exceeds 5% by mass, the impact resistance imparting effect of the acrylic organic rubber particles is lowered, which is not preferable.

The copolymer forming the outermost layer (b-iii) of the acrylic organic rubber particles is a copolymer composed of methyl methacrylate units and other copolymerizable monomer units copolymerizable therewith. A coalescence can be preferably used.
Examples of the other copolymerizable monomers include methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, etc., and these may be used alone. Two or more species may be used in combination. In particular, n-butyl acrylate and 2-hexyl acrylate are preferable, acrylic ester is more preferable, and n-butyl acrylate and 2-hexyl acrylate are more preferable.
The ratio of the acrylate monomer in the outermost layer (b-iii) is preferably 1 to 20% by mass. When the proportion is less than 1% by mass, the thermal decomposability of the polymer increases. On the other hand, when the unit exceeds 20% by mass, the adhesiveness of the acrylic organic rubber particles increases and is handled in post-treatment and the like. As a result, the compatibility with the methacrylic resin is lowered, and the impact resistance and weather resistance are lowered.

The method for producing the acrylic organic rubber particles is not particularly limited, and can be obtained by a known polymerization method such as bulk polymerization, solution polymerization, suspension polymerization and emulsion polymerization, and in particular, obtained by emulsion polymerization. Is preferred.
In this case, in the presence of an emulsifier and an initiator, the monomer mixture of the innermost layer (bi) is first added to complete the polymerization, and then the monomer mixture of the central layer (b-ii) is added. By completing the polymerization and then adding the monomer mixture of the outermost layer (b-iii) to complete the polymerization, the multilayer structure particles can be easily obtained as a latex.
The acrylic organic rubber particles can be recovered from the latex as a powder by a known method such as salting out, spray drying or freeze drying.

<Inorganic filler>
The inorganic filler is not particularly limited. For example, glass fiber, carbon fiber, calcium silicate fiber, potassium titanate fiber, aluminum borate fiber, glass flake, talc, kaolin, mica, hydrotalcite , Calcium carbonate, zinc carbonate, zinc oxide, calcium monohydrogen phosphate, wollastonite, silica, zeolite, alumina, boehmite, aluminum hydroxide, titanium oxide, silicon oxide, magnesium oxide, calcium silicate, sodium aluminosilicate, silica Magnesium acid, Ketjen black, Acetylene black, Furnace black, Carbon nanotube, Graphite, Brass, Copper, Silver, Aluminum, Nickel, Iron, Calcium fluoride, Mica, Montmorillonite, Swellable fluoromica, and Apatai Etc. The.
One type of inorganic filler may be used alone, or two or more types may be used in combination.
Glass fiber, carbon fiber, glass flake, talc, kaolin, mica, calcium carbonate, calcium monohydrogen phosphate, wollastonite, silica, carbon nanotube, graphite, calcium fluoride, montmorillonite, swelling from the viewpoint of rigidity and strength Fluorine mica and apatite are preferred.
In addition, these inorganic fillers may be appropriately subjected to surface treatment for the purpose of being more familiar with the methacrylic resin (A).

<Colorant>
Examples of the colorant include perylene dyes, perinone dyes, pyrazolone dyes, methine dyes, coumarin dyes, quinophthalone dyes, quinoline dyes, anthraquinone dyes, anthraquinone dyes, asdrapyridone dyes, and thioindigo dyes. Dyes, coumarin dyes, isoindolinone pigments, syketopyrrolopyrrole pigments, condensed azo pigments, benzimidazolone pigments, dioxazine pigments, copper phthalocyanine pigments, quinacridone pigments, nickel complex compounds, carbon black , Titanium dioxide, Alumina oxide, Aluminum hydroxide, Silicic acid, Zinc oxide, Zinc stearate, Magnesium stearate, Calcium stearate, Aluminum stearate, Barium sulfate, Polymethylsilsesquioxane, Copper halide phthalocyanine Ethylene bis-stearic acid amide, ultramarine, ultramarine violet, iron oxide, silicon dioxide, mica, talc, liquid paraffin, magnesium silicate, and the like.
One colorant may be used alone, or two or more colorants may be used in combination.

  The above-mentioned additive (B) composed of resin particle powder, organic rubber particles, inorganic filler, and colorant may be used singly or in combination of two or more.

[Method for producing methacrylic resin composition for melt molding]
The methacrylic resin composition of this embodiment can be obtained by mixing the methacrylic resin (A), the additive (B), and other resins and additives as necessary.
The methacrylic resin as component (A) can be produced by the method described above in [Method for producing methacrylic resin for melt molding].
As a method of kneading the component (A) and the component (B), as well as other resins and additives, a conventionally known method may be used, and there is no particular limitation.
For example, it can be kneaded and produced using a kneader such as an extruder, a heating roll, a kneader, a roller mixer, a Banbury mixer and the like.
In particular, 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 produced according to the present invention and other resins to be mixed, and is generally in the range of 140 to 300 ° C, preferably in the range of 180 to 280 ° C.

[Molded product of methacrylic resin composition]
A desired molded article is obtained by molding the methacrylic resin composition of the present embodiment described above.
The methacrylic resin composition can be molded by a known method of molding in a molten state such as injection molding, sheet molding, blow molding, injection blow molding, inflation molding, T-die molding, press molding, extrusion molding, and the like. Secondary processing molding methods such as pressure forming and vacuum forming can also be used.
In particular, injection molding that requires fluidity is preferable, and effective for melt molding at high pressure and high speed.
A method of kneading and producing a methacrylic resin composition using a kneader such as a heating roll, kneader, Banbury mixer, extruder, etc., cooling, pulverizing, and further molding by transfer molding, injection molding, compression molding, etc. Can also be cited as an example.
The order of mixing the components is not particularly limited as long as the effect of the present invention can be achieved.
Moreover, although the hardening method after mixing thermosetting resin and melt-molding changes with hardeners to be used, there is no limitation in particular.
For example, heat curing, light curing, UV curing, curing by pressure, curing by moisture, and the like can be given.

[Characteristics of methacrylic resin and methacrylic resin composition]
<Fluidity>
In the methacrylic resin and the methacrylic resin composition of the present embodiment, the measured value of the length of the spiral part is preferably 22 cm or more, and is 23 cm or more in the fluidity evaluation condition of the spiral length in Examples described later. More preferably, it is more preferably 24 cm or more.
If it is 22 cm or more, the fluidity at the time of molding will be good.
Usually, in order to improve fluidity, there are methods such as reducing the weight average molecular weight or increasing the ratio of low molecular weight components. However, according to the molten methacrylic resin and methacrylic resin composition of the present embodiment, it can be easily achieved with high accuracy. it can.

<Solvent resistance>
Moreover, in the solvent resistance evaluation by the cantilever method in the examples described later, the breaking time of the molded body using the methacrylic resin and the methacrylic resin composition of the present embodiment is preferably 200 seconds or more, more preferably 300 seconds or more. Preferably, 400 seconds or more are more preferable. Since it is 200 seconds or more, it has high solvent resistance.

<Heat resistance>
Further, the Vicat softening temperature of the methacrylic resin and methacrylic resin composition of the present embodiment is preferably 100 ° C. or higher, more preferably 104 ° C. or higher, and particularly preferably 106 ° C. or higher.
Since the Vicat value is 100 ° C. or higher, heat resistance can be ensured.
Usually, this heat resistance is largely due to the proportion of at least one other vinyl monomer unit copolymerizable with the methacrylic acid ester monomer, and is difficult to control in balance with fluidity. The methacrylic resin and methacrylic resin composition of the embodiment can be easily achieved with high accuracy.

<Impact resistance>
The Charpy impact strength (without notch) of the molded body using the methacrylic resin and the methacrylic resin composition of the present embodiment is preferably 24 kJ / m ² or more, more preferably 25 kJ / m ² , and 26 kJ / m. ² is more preferable. Since the impact strength is 24 kJ / m ² or more, it can be suitably used for applications requiring impact strength.

<Strongness>
The stringability of the molded body using the methacrylic resin and the methacrylic resin composition of the present embodiment is preferably such that no long yarn is generated at a temperature of 245 ° C., even under a high-temperature treatment at 380 ° C. or higher. It is more preferable that the long yarn generation rate is low.
In addition, about the stringing property, a specific evaluation method is shown in the examples described later, but a phenomenon in which a thread is generated when a molded piece is pressed against a heated hot plate and the molten molded piece is pulled away from the hot plate. If the resistance to stringing is poor, the appearance of the welded part of the molded body will be poor.

<Transparency>
Furthermore, the methacrylic resin and the methacrylic resin composition of the present embodiment preferably have a total light transmittance of 90% or more, more preferably 91% or more, and further preferably 92% or more. . When the total light transmittance is 92% or more, it can be determined that the film has high transparency.

[Use]
The methacrylic resin and methacrylic resin composition of the present embodiment can be suitably used for various melt-molded bodies.
For example, furniture, household goods, storage and stockpiling equipment, toys and playground equipment, medical and welfare equipment, OA equipment, AV equipment, battery electrical equipment, lighting equipment, vehicle parts, especially automobile parts use, housing use, sanitary use, Can be used for water-related products such as kitchens, toilets, baths, and bathrooms.
In particular, in vehicle applications, it can be used for tail lamp covers, head lamp covers, rear combination lamp covers, lid lamp covers, etc. Due to its excellent fluidity and solvent resistance, It can be suitably used.
Furthermore, light guide plates, diffusion plates, polarizing plate protective films, 1/4 wavelength plates, 1/2 wavelength plates, viewing angles used in displays such as liquid crystal displays, plasma displays, organic EL displays, field emission displays, rear projection televisions, etc. Examples thereof include a retardation film such as a control film and a liquid crystal optical compensation film, a display front plate, a display substrate, a lens, a touch panel and the like, and can also be suitably used for a transparent substrate used for a solar cell.
In addition, in the fields of optical communication systems, optical switching systems, and optical measurement systems, they can also be used for waveguides, lenses, optical fibers, optical fiber coating materials, LED lenses, lens covers, and the like. In particular, it can be suitably used for injection molding in which molding is performed with pressure during molding processing, and further for large or thin molding applications in applications having solvent resistance and mechanical strength.
The molded body using the methacrylic resin for melt molding and the methacrylic resin composition for melt molded body is subjected to surface functionalization treatment such as hard coat treatment, antireflection treatment, transparent conductive treatment, electromagnetic wave shielding treatment, gas barrier treatment, etc. You can also

  Hereinafter, the present invention will be described with reference to specific examples and comparative examples, but the present invention is not limited thereto.

[Examples and comparative examples of the invention relating to methacrylic resins]
(material)
・ Methyl methacrylate (MMA): manufactured by Asahi Kasei Chemicals (manufactured by Chugai Trading as a polymerization inhibitor, 2,4-dimethyl-6-tert-butylphenol (2,4-di-methyl-6-
tert-butylphenol) to which 2.5 ppm is added)
-Methyl acrylate (MA): manufactured by Mitsubishi Chemical (added with 14 ppm 4-methoxyphenol manufactured by Kawaguchi Chemical Industry as a polymerization inhibitor)
N-octyl mercaptan: Arkema 2-ethylhexyl thioglycolate (2-ethylhexyl thiogly)
(colate): manufactured by Arkema, lauroyl peroxide: manufactured by Nippon Oil & Fats, tricalcium phosphate (produced by Nippon Chemical Industry Co., Ltd.)
Used as a suspending agent ・ Calcium carbonate: Shiraishi Kogyo, used as a suspending agent ・ Sodium lauryl sulfate: Wako Pure Chemicals, used as a suspending aid

(Measurement method)
<I. Measurement of methacrylic resin composition and molecular weight>
(1) Composition analysis of methacrylic resin The composition analysis of the methacrylic resin was performed by pyrolysis gas chromatography and mass spectrometry.
Pyrolysis device: PY-2020D made by FRONTIER LAB
Column: DB-1 (length 30 m, inner diameter 0.25 mm, liquid phase thickness 0.25 μm)
Column temperature program: held at 40 ° C. for 5 min, then heated to 320 ° C. at a rate of 50 ° C./min, and held at 320 ° C. for 4.4 minutes Pyrolysis furnace temperature: 550 ° C.
Column inlet temperature: 320 ° C
Gas chromatography: Agilent GC6890
Carrier: pure nitrogen, flow rate 1.0 mL / min
Injection method: Split method (split ratio 1/200)
Detector: JEOL mass spectrometer Automass Sun
Detection method: electron impact ionization method (ion source temperature: 240 ° C., interface temperature: 3
20 ° C)
Sample for measurement: 10 μL of 10 g chloroform solution of 0.1 g methacrylic resin

A sample for measurement was collected in a platinum sample cup for a thermal decomposition apparatus, and after vacuum drying at 150 ° C. for 2 hours, the sample cup was placed in a thermal decomposition furnace, and composition analysis of the sample was performed under the above conditions.
The composition ratio of the methacrylic resin was determined based on the peak area on the total ion chromatography (TIC) of methyl methacrylate and methyl acrylate and the calibration curve of the following standard sample.
Preparation of standard sample for calibration curve: The ratio of methyl methacrylate and methyl acrylate is (methyl methacrylate / methyl acrylate) = (100% / 0%), (98% / 2%), (94% / 6% ), (90% / 10%) (80% / 20%), respectively, 0.25% lauroyl peroxide and 0.25% n-octyl mercaptan were added to 50 g of each of the five solutions.
Each mixed solution was put into a 100 cc glass ampule bottle, and the air was replaced with nitrogen and sealed.
The glass ampoule bottle was placed in an 80 ° C. water bath for 3 hours and then in an oven at 150 ° C. for 2 hours. After cooling to room temperature, the glass was crushed and the methacrylic resin inside was taken out and subjected to composition analysis. A graph of (methyl acrylate area value) / (methyl methacrylate area value + methyl acrylate area value) and methyl acrylate charge ratio obtained by measurement of a standard sample for a calibration curve is used as a calibration curve. It was.
This analyzed the ratio of the amount of methyl methacrylate and other components of methacrylic resin, and the amount of Mh and Ml.

(2) Measuring and measuring apparatus for weight average molecular weight and molecular weight distribution of methacrylic resin: Gel Permeation Chromatography (LC-908) manufactured by Japan Analytical Industry
Column: 1 JAIGEL-4H and 2 JAIGEL-2H in series connection In this column, the high molecular weight elutes early, and the low molecular weight elutes slowly.
Detector: RI (differential refraction) detector Detection sensitivity: 2.4 μV / sec
Sample: 0.450 g of methacrylic resin in chloroform (15 mL) Injection amount: 3 mL
Developing solvent: chloroform, flow rate 3.3 mL / min
Under the above conditions, the RI detection intensity with respect to the elution time of the methacrylic resin was measured.
Based on the area area in the GPC elution curve and the calibration curve, the weight average molecular weight (Mw), molecular weight distribution (Mw / Mn), GPC peak weight average molecular weight (Mp) and peak weight average molecular weight (Mp) of the methacrylic resin The ratio (%) of the component having a weight average molecular weight (Mw) of 1/5 or less 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
When the polymer (I) and the polymer (II) are mixed, the GPC elution curve of the polymer (I) alone is measured in advance to obtain the weight average molecular weight, and the polymer (I) is present. Is multiplied by the GPC elution curve of the polymer (I) and the detected intensity at the elution time is mixed between the polymer (I) and the polymer (II). The GPC elution curve of the polymer (II) alone was obtained by subtracting from the GPC elution curve. From this, the weight average molecular weight of the polymer (II) was determined.

<II. Physical property measurement>
(1) Measurement of spiral length A test was performed to determine relative fluidity according to the distance that each resin flowed through a spiral cavity having a constant cross-sectional area.
Injection molding machine: Toshiba Machine IS-100EN
Mold for measurement: Mold having a groove with a depth of 2 mm and a width of 12.7 mm dug in the Archimedes spiral shape from the center of the surface on the mold surface Injection conditions Resin temperature: 250 ° C.
Mold temperature: 55 ° C
Injection pressure: 98MPa, 73.5MPa, 122.5MPa
Injection time: 20 sec
Resin was injected into the center of the mold surface under the above conditions. After 40 seconds from the end of injection, the spiral molded product was taken out, and the length of the spiral portion was measured. This was used as an index for liquidity evaluation.
Further, the injection pressure was changed at a constant temperature, the slope when the pressure was plotted on the horizontal axis and the spiral length was plotted on the vertical axis was calculated, and the fluidity due to the pressure was evaluated.

(2) Measurement of rupture time by cantilever method Solvent resistance was evaluated by the measurement method by the cantilever method shown in FIG.
Injection molding machine: Toshiba Machine IS-100EN
Injection molded body (test piece): thickness 3.2 mm width 12.7 mm length 127 mm
Injection conditions Molding temperature: 230 ° C
Mold temperature: 60 ℃
Injection pressure: 65MPa
Injection time: 20 sec
Cooling time: 40 sec
The molded product of the methacrylic resin of Examples and Comparative Examples molded under the above conditions was stored in a desiccator for 1 day so as not to absorb water.
After that, using the jig 1 shown in FIG. 4, a molded body 2 as a test piece was installed as shown in FIG. 4, and a 3 kg weight 3 attached with an octopus thread 5 was attached as shown in FIG. The filter paper 4 was placed at the position shown in FIG. 4, and the time from when the filter paper 4 was placed until the molded body 2 was broken by the weight 3 was measured.
The above measurement was repeated 10 times for each sample, the maximum time and minimum time data were deleted, and the remaining 8 average times (seconds) were obtained.
This was used as an index for solvent resistance evaluation.

(3) Measurement of VICAT softening temperature Based on ISO 306 B50, measurement was performed using a 4 mm-thick test piece to obtain a VICAT softening temperature, which was used as an index for heat resistance evaluation.

(4) Transparency (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.

(5) Charpy impact strength (no notch)
Measurement was performed in accordance with the ISO 179 / 1eU standard and used as an index of impact resistance.

(6) Measurement of stringing resistance 20 pieces of resin 1 and 12, which will be described later, and the resin obtained in the comparative example were molded into a width of 20 mm, a length of 75 mm, and a thickness of 2 mm were prepared as test pieces.
The hot plate was heated to a surface temperature of 245 ° C. using a hot plate welder (manufactured by Takagi Seiko). As the hot plate, a metal plate obtained by processing the surface of an aluminum plate with Teflon (registered trademark) was used.
The 20 mm × 2 mm surface of the test piece was pressed against the hot plate at a speed of 1 mm / s, pushed to 0.7 ± 0.2 mm from the contacted position, contacted for 20 seconds, and then tested at a speed of 20 ± 10 mm / s. When the piece was released, the long yarn generation rate (%) was calculated from the number of test pieces in which a resin yarn of 5 mm or more was generated, and was defined as the stringiness.
Furthermore, the surface temperature of the hot plate was heated to 390 ° C., and the same test was performed.
It was evaluated that the longer the yarn generation rate (%), the better the stringing resistance.

[Example 1]
In a container having a stirrer, 2 kg of water, 65 g of tricalcium phosphate, 39 g of calcium carbonate, and 0.39 g of sodium lauryl sulfate were added to obtain a mixed solution (a).
Next, 4500 g of water was charged into a 60 L reactor, the temperature was raised to 80 ° C., and the raw material of the polymer (I) (raw material (I )).
Thereafter, suspension polymerization was carried out while maintaining the temperature at about 80 ° C. An exothermic peak was observed 80 minutes after adding the raw material of the polymer (I).
Thereafter, the temperature was raised to 92 ° C. at a rate of 1 ° C./min, and then maintained at a temperature of 92 ° C. to 94 ° C. for 30 minutes.
Thereafter, the temperature was lowered to 80 ° C. at a rate of 1 ° C./min, and then the raw material for polymer (II) (raw material (II) in Table 1) was charged into the reactor at the blending amount shown in Table 1 below. Subsequently, suspension polymerization was carried out while maintaining the temperature at about 80 ° C. An exothermic peak was observed 105 minutes after charging the raw material of the polymer (II).
Thereafter, the temperature was raised to 92 ° C. at a rate of 1 ° C./min and then aged for 60 minutes to substantially complete the polymerization reaction.
Next, in order to cool to 50 ° C. and dissolve the suspending agent, 20 mass% sulfuric acid was added.
Subsequently, the polymerization reaction solution was passed through a 1.68 mm mesh sieve to remove aggregates, and the obtained bead polymer was washed and dehydrated and dried to obtain polymer fine particles corresponding to Resin 1.

  Table 2 below shows the monomer charge composition ratio, the weight average molecular weight (Mw), and the ratio of the polymer (I) to the polymer (II) of the polymer (I) and the polymer (II).

The agglomerates are dried in an oven at 80 ° C. for 12 hours and weighed, and the weight is divided by the total amount of the raw material (I) and the raw material (II) to obtain an aggregate production amount (%). It was 0.5% when measured.
Furthermore, the particle diameter of the obtained polymer fine particles was 0.26 μm.
The obtained polymer fine particles were melt-kneaded with a φ30 mm twin screw extruder set at 240 ° C., and the strands were cooled and cut to obtain resin pellets (resin 1).
The weight average molecular weight of the obtained pellet was 172,000, the peak weight average molecular weight (Mp) was 197,000, and the molecular weight distribution (Mw / Mn) was 3.65.
Moreover, as a result of the compositional analysis by pyrolysis gas chromatography (GC), the composition of the methacrylic resin was MMA: 96.6% by mass and MA: 3.4% by mass.
Furthermore, the abundance (%) of the weight average molecular weight component of 1/5 or less of the Mp value is 24.5%, Mh of 0 to 2% portion from the GPC area high molecular weight side: 4.5%, the GPC area high molecular weight side From 98 to 100%, part Ml: 0.2%. These are shown in Table 3.

Further, when the fluidity of the obtained resin pellet (resin 1) was measured by the spiral length, it was 26.6 cm when 250 ° C. and the injection pressure was 98 MPa.
It was 700 s when the fracture time of the molded body using (resin 1) by the cantilever method was measured.
Moreover, it was 108 degreeC when the VICAT softening temperature was measured.
The total light transmittance was measured and found to be 92%.
When Charpy impact strength (without notch) was measured as an index of impact resistance, it was 26.8 kJ / m ² .
Furthermore, in the measurement evaluation of the spiral length, the injection pressure was changed to 73.5 MPa and 122.5 MPa, the length was measured, and the obtained result was plotted with the injection pressure on the horizontal axis and the spiral length on the vertical axis. It was 0.33 when the inclination (inclination by the change of the injection pressure of a spiral) was seen.

[Examples 2 to 10 ], [Reference Example 11], [Examples 12 to 16], [Comparative Examples 1 to 7, 9]
Polymerization was performed in the same manner as in Example 1 using the raw materials shown in Table 1 to obtain polymer fine particles corresponding to the resins 2 to 24.
In addition, resin pellets were prepared in the same manner as in Example 1, and the weight average molecular weight (Mw), molecular weight distribution (Mw / Mn), GPC peak weight average molecular weight (Mp), and peak weight average molecular weight (Mp) 1 / Ratio (%) of component having weight average molecular weight (Mw) of 5 or less, Mh (%) of 0-2% portion from GPC area high molecular weight side, Ml (%) of 98-100% portion from GPC area high molecular weight side ) These are shown in Table 3.
In addition, Table 4 shows the physical property measurement results of the obtained resin pellets.

[Comparative Example 8]
2 kg of water, 65 g of tricalcium phosphate, 39 g of calcium carbonate, and 0.39 g of sodium lauryl sulfate were put into a container having a stirrer to obtain a mixed solution (a ′).
Subsequently, 26 kg of water was charged into a 60 L reactor and the temperature was raised to 80 ° C., and the mixture (a ′) and methyl methacrylate 21.2 kg, methyl acrylate 1.35 kg, lauroyl peroxide 27 g, n-octyl mercaptan 32.8 g was charged.
Thereafter, suspension polymerization was carried out while maintaining about 80 ° C., and after observing an exothermic peak, the temperature was raised to 92 ° C. at a rate of 1 ° C./min. Thereafter, the mixture was aged for 60 minutes to substantially complete the polymerization reaction.
Subsequently, 20 mass% sulfuric acid was added in order to cool to 50 ° C. and dissolve the suspending agent.
Next, the polymerization reaction solution was passed through a 1.68 mm mesh sieve to remove aggregates, and the resulting bead polymer was washed and dehydrated and dried to obtain polymer fine particles.

The aggregate was dried in an oven at 80 ° C. for 12 hours, weighed, and the amount of aggregate formed was calculated to be 0.52%. Furthermore, the particle size of the obtained polymer fine particles was 0.28 μm.
The obtained polymer fine particles were melt-kneaded with a φ30 mm twin screw extruder set at 240 ° C., and the strands were cooled and cut to obtain resin pellets.
The weight average molecular weight of the obtained pellet was 176,000, and the molecular weight distribution (Mw / Mn) was 1.9. Further, the Mp value is 1760,000, the abundance (%) of the weight average molecular weight component of 1/5 or less of the Mp value is 4.8%, and the Mh in the 0-2% portion from the GPC area high molecular weight side: It was 5.8%, 98-100% portion Gl from the high molecular weight side of GPC area: 5.7%.
In addition, Table 4 shows the physical property measurement results of the resin pellets of Comparative Example 8.

For Examples 2, 3, 4, 6, 7, Reference Example 11, and Comparative Example 8, as in Example 1 above, the inclination when the injection pressure is plotted on the horizontal axis and the spiral length is plotted on the vertical axis (spiral (Slope value due to change in injection pressure) was found to be: Example 2: 0.31, Example 3: 0.32, Example 4: 0.30, Example 6: 0.31, Example 7: 0.35, Reference Example 11: 0.29, and Comparative Example 8: 0.25.

In Examples 1-4, 8, 9, and 12, since Mw and Mw / Mn were appropriate, the spiral length was 23 cm or more, the rupture time of the solvent resistance test was 400 seconds or more, and the Vicat value was 107 ° C. As a result, a resin having an excellent balance of fluidity, solvent resistance and heat resistance could be obtained.
Further, the occurrence rate of long yarn at 245 ° C. was 0%, and the occurrence rate of long yarn at a high temperature of 390 ° C. was also 0%. It was found to be very effective for applications requiring hot plate welding treatment.
In Examples 5 to 7, the content of methyl acrylate was slightly high, and a slight decrease in heat resistance was observed as compared with other examples, but the fluidity and solvent resistance were good.

In Example 10 and Reference Example 11, Mw / Mn was around 3.0 and the fluidity was slightly lowered as compared with the other examples, but the heat resistance and solvent resistance were good. Further, since Mw / Mn was around 3.0, the long yarn generation rate at 390 ° C. was 5%.
In Examples 13 and 14, since the above conditions (iii), which are preferable conditions for Mh and Ml, are not satisfied, heat resistance in Example 13 and fluidity in Example 14 are other examples. Although it was somewhat inferior to, other physical property balances showed good values.
8 ≧ (Mh−2) ≧ Ml ≧ 0 (iii)
In Example 15, when the polymer (I) was polymerized, another vinyl monomer copolymerizable with the methacrylic acid ester monomer was added that satisfies the following formula (ii).
(Mh−0.8) ≧ Ml ≧ 0 (ii)
As a result, a resin composition having a good balance of fluidity, solvent resistance, and heat resistance was obtained.
In Example 16, the content of methyl acrylate was slightly higher, and a slight decrease in heat resistance was seen compared to the other examples, but it was more preferable than the conventional example.

In Comparative Examples 1 and 3, since the weight average molecular weight (Mw) and the molecular weight distribution (Mw / Mn) were not appropriate, the mechanical strength and the solvent resistance were deteriorated. Further, the long yarn generation rate at 245 ° C. and 390 ° C. was not preferable.
In Comparative Examples 2 and 5, since the weight average molecular weight (Mw) was not appropriate, the mechanical strength and the solvent resistance were not preferable. Furthermore, in Comparative Example 5, the occurrence rate of long yarns at 245 ° C. and 390 ° C. was not preferable.
In Comparative Example 4, the weight average molecular weight (Mw) was appropriate, but the molecular weight distribution (Mw / Mn) was not appropriate, so the fluidity deteriorated. Further, the occurrence rate of long yarn at 390 ° C. was not preferable.
In Comparative Example 6, since the other vinyl monomer unit copolymerizable with the methacrylic ester monomer in the composition of the methacrylic resin is 1.0% by mass, a balance between solvent resistance and fluidity is preferable. There wasn't.
In Comparative Example 7, since Mw / Mn = 5.9, the balance between fluidity and solvent resistance deteriorated.
Furthermore, in Comparative Example 9, since the abundance (%) of the weight average molecular weight component of 1/5 or less of the Mp value is 17.3%, the physical property balance is bad, and the occurrence rate of long yarn at 390 ° C. is also preferable. There wasn't.

When Examples 1, 3, 8, 9 and Comparative Example 8 are compared, the methacrylic resin of the example has high fluidity, equivalent solvent resistance and Charpy impact strength, despite the similar weight average molecular weight. It was found that heat resistance was maintained.
Furthermore, the inclination by the pressure change of the spiral of the resin obtained in Comparative Example 8 measured under the same conditions as in Example 1 was 0.25. Therefore, it was found that the methacrylic resin obtained in Example 1 was excellent in molding under high pressure as compared with the resin obtained in Comparative Example 8.
Furthermore, although the weight average molecular weight of Comparative Example 8 was larger, the generation rate of long yarn at a high temperature of 390 ° C. was better in Example 1.

[Examples and comparative examples for methacrylic resin compositions]
(material)
The raw materials used are as follows.
・ Methyl methacrylate (MMA): manufactured by Asahi Kasei Chemicals (manufactured by Chugai Trading as a polymerization inhibitor, 2,4-dimethyl-6-tert-butylphenol (2,4-di-methyl-6-
tert-butylphenol) to which 2.5 ppm is added)
・ Methyl acrylate (MA): manufactured by Mitsubishi Chemical (14-ppm of 4-methoxyphenol manufactured by Kawaguchi Chemical Industry is added as a polymerization inhibitor)
N-octyl mercaptan: Arkema 2-ethylhexyl thioglycolate (2-ethylhexyl thiogly)
(colate): manufactured by Arkema, lauroyl peroxide: manufactured by Nippon Oil & Fats, tricalcium phosphate (produced by Nippon Chemical Industry Co., Ltd.)
Used as suspending agent ・ Calcium carbonate: manufactured by Shiraishi Kogyo Co., Ltd. used as suspending agent ・ Sodium lauryl sulfate: manufactured by Wako Pure Chemical Industries, Ltd. used as suspending aid

(Measurement method)
<I. Measurement of resin composition and molecular weight>
(1) Composition analysis of methacrylic resin The composition analysis of methacrylic resin was performed by pyrolysis gas chromatography and mass spectrometry.
Pyrolysis device: PY-2020D made by FRONTIER LAB
Column: DB-1 (length 30 m, inner diameter 0.25 mm, liquid phase thickness 0.25 μm)
Column temperature program: held at 40 ° C. for 5 min, then heated to 320 ° C. at a rate of 50 ° C./min, and held at 320 ° C. for 4.4 minutes Pyrolysis furnace temperature: 550 ° C.
Column inlet temperature: 320 ° C
Gas chromatography: Agilent GC6890
Carrier: pure nitrogen, flow rate 1.0 ml / min
Injection method: Split method (split ratio 1/200)
Detector: JEOL mass spectrometer Automass Sun
Detection method: Electron impact ionization method (ion source temperature: 240 ° C., interface temperature: 320 ° C.)
Sample for measurement: 10 μL of 10 g chloroform solution of 0.1 g methacrylic resin

A sample for measurement was collected in a platinum sample cup for a thermal decomposition apparatus, and after vacuum drying at 150 ° C. for 2 hours, the sample cup was placed in a thermal decomposition furnace, and composition analysis of the sample was performed under the above conditions.
The composition ratio of the methacrylic resin was determined based on the peak area on the total ion chromatography (TIC) of methyl methacrylate and methyl acrylate and the calibration curve of the following standard sample.
Preparation of standard sample for calibration curve: The ratio of methyl methacrylate and methyl acrylate is (methyl methacrylate / methyl acrylate) = (100% / 0%), (98% / 2%), (94% / 6% ), (90% / 10%) (80% / 20%), respectively, 0.25% lauroyl peroxide and 0.25% n-octyl mercaptan were added to 50 g of each of the five solutions.
Each of these mixed solutions was put into a 100 cc glass ampule bottle, and the air was replaced with nitrogen and sealed.
The glass ampoule bottle was placed in an 80 ° C. water bath for 3 hours and then in an oven at 150 ° C. for 2 hours.
After cooling to room temperature, the glass was crushed and the methacrylic resin inside was taken out and subjected to composition analysis.
A graph of (methyl acrylate area value) / (methyl methacrylate area value + methyl acrylate area value) and methyl acrylate charge ratio obtained by measurement of a standard sample for a calibration curve is used as a calibration curve. It was.
This analyzed the ratio of the amount of methyl methacrylate and other components of methacrylic resin, and the amount of Mh and Ml.

(2) Measurement and measurement device for weight average molecular weight and molecular weight distribution of methacrylic resin: Gel Permeation Chromatography (LC-908) manufactured by Nippon Analytical Industry
Column: 1 JAIGEL-4H and 2 JAIGEL-2H in series connection In this column, the high molecular weight elutes early, and the low molecular weight elutes slowly.
Detector: RI (differential refraction) detector Detection sensitivity: 2.4 μV / sec
Sample: 0.450 g of methacrylic resin in chloroform (15 mL) Injection amount: 3 mL
Developing solvent: chloroform, flow rate 3.3 mL / min
Under the above conditions, the RI detection intensity with respect to the elution time of the methacrylic resin was measured.
Based on the area area in the GPC elution curve and the calibration curve, the weight average molecular weight (Mw), molecular weight distribution (Mw / Mn), GPC peak weight average molecular weight (Mp) and peak weight average molecular weight (Mp) of the methacrylic resin The ratio (%) of the component having a weight average molecular weight (Mw) of 1/5 or less 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
When the polymer (I) and the polymer (II) are mixed, the GPC elution curve of the polymer (I) alone is measured in advance to obtain the weight average molecular weight, and the polymer (I) is present. Is multiplied by the GPC elution curve of the polymer (I) and the detected intensity at the elution time is mixed between the polymer (I) and the polymer (II). The GPC elution curve of polymer (II) alone was obtained by subtracting from the GPC elution curve.
From this, the weight average molecular weight of the polymer (II) was determined.

<II. Physical property measurement>
(1) Measurement of spiral length Test for determining relative fluidity based on the distance through which resin compositions of Examples 17 to 29 and Comparative Examples 10 to 15 described later flow in a spiral cavity having a constant cross-sectional area. Went.
Injection molding machine: Toshiba Machine IS-100EN
Mold for measurement: Mold having a groove with a depth of 2 mm and a width of 12.7 mm dug in the Archimedes spiral shape from the center of the surface on the mold surface Injection conditions Resin temperature: 250 ° C.
Mold temperature: 55 ° C
Injection pressure: 98MPa, 73.5MPa, 122.5MPa
Injection time: 20 sec
Resin was injected into the center of the mold surface under the above conditions. After 40 seconds from the end of injection, the spiral molded product was taken out, and the length of the spiral portion was measured. This was used as an index for liquidity evaluation.
Further, the injection pressure was changed at a constant temperature, the slope when the pressure was plotted on the horizontal axis and the spiral length was plotted on the vertical axis was calculated, and the fluidity due to the pressure was evaluated.

(2) Break time measurement by cantilever method (solvent resistance test)
The solvent resistance was evaluated by the measuring method by the cantilever method shown in FIG.
Injection molding machine: Toshiba Machine IS-100EN
Injection molded body (test piece): thickness 3.2 mm width 12.7 mm length 127 mm
Injection conditions Molding temperature: 230 ° C
Mold temperature: 60 ℃
Injection pressure: 65MPa
Injection time: 20 sec
Cooling time: 40 sec
The molded body molded under the above conditions was stored in a desiccator for 1 day so as not to absorb water.
After that, using the jig 1 shown in FIG. 4, a molded body 2 as a test piece was installed as shown in FIG. 4, and a 3 kg weight 3 attached with an octopus thread 5 was attached as shown in FIG. The filter paper 4 was placed at the position shown in FIG. 4 and the time from when the filter paper 4 was placed until the molded article was broken by the weight 3 was measured.
The above measurement was repeated 10 times for each sample, the maximum time and minimum time data were deleted, and the remaining 8 average times (seconds) were obtained. This was used as an index for solvent resistance evaluation.

(3) Measurement of VICAT softening temperature Based on ISO 306 B50, measurement was performed using a 4 mm-thick test piece to obtain a VICAT softening temperature, which was used as an index for heat resistance evaluation.

(4) Charpy impact strength (no notch)
Measurement was performed in accordance with the ISO 179 / 1eU standard and used as an index of impact resistance.

(5) Evaluation of processing stability (evaluation during pelletization)
The processing stability evaluation when the resin compositions of Examples 17 to 29 and Comparative Examples 10 to 15 described below were pelletized with a twin screw extruder of φ30 mm set at 250 ° C. was evaluated as ◎ to ×. .
Almost cut off: ◎, slightly cut off: ○, slightly cut off: △, practical problems cut to some extent: ×

Example 17
In this example, a resin composition containing (A) component: methacrylic resin and (B) component: additive was prepared.
((A) component: Production of methacrylic resin)
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 to obtain a mixed solution (a).
Next, 4500 g of water was put into a 60 L reactor and the temperature was raised to 80 ° C., and the raw material of the polymer (I) (raw material in Table 5) with the mixture (a) and the blending amount shown in Table 5 below I)).
Thereafter, suspension polymerization was carried out while maintaining the temperature at about 80 ° C. An exothermic peak was observed 80 minutes after adding the raw material of the polymer (I).
Thereafter, the temperature was raised to 92 ° C. at a rate of 1 ° C./min, and then maintained at a temperature of 92 ° C. to 94 ° C. for 30 minutes.
Thereafter, the temperature was lowered to 80 ° C. at a rate of 1 ° C./min, and then the raw material for polymer (II) (raw material (II) in Table 5) was added to the reactor in the amount shown in Table 5 below. Subsequently, suspension polymerization was carried out while maintaining the temperature at about 80 ° C.
An exothermic peak was observed 105 minutes after charging the raw material of the polymer (II).
Thereafter, the temperature was raised to 92 ° C. at a rate of 1 ° C./min and then aged for 60 minutes to substantially complete the polymerization reaction.
Next, in order to cool to 50 ° C. and dissolve the suspending agent, 20 mass% sulfuric acid was added.
Next, the polymerization reaction solution was passed through a 1.68 mm mesh sieve to remove aggregates, and the obtained bead polymer was washed and dehydrated and dried to obtain polymer fine particles corresponding to resin A1 in Table 5.

  The monomer charge composition ratios of the polymer (I) and the polymer (II), the respective weight average molecular weights (Mw), and the ratios of the polymers (I) and (II) are shown in Table 6 below.

The agglomerates are dried in an oven at 80 ° C. for 12 hours and weighed, and the weight is divided by the total amount of the raw material (I) and the raw material (II) to obtain an aggregate production amount (%). It was 0.5% when measured.
The obtained polymer fine particles had a particle size of 0.26 μm.
The obtained polymer fine particles were melt-kneaded with a φ30 mm twin screw extruder set at 240 ° C., and the strands were cooled and cut to obtain resin pellets (resin A1).
The weight average molecular weight of the obtained pellet was 172,000, the peak weight average molecular weight (Mp) was 197,000, and the molecular weight distribution (Mw / Mn) was 3.65.
Moreover, as a result of the compositional analysis by pyrolysis gas chromatography (GC), the composition of the methacrylic resin was MMA: 96.6% by mass and MA: 3.4% by mass.
Furthermore, the abundance (%) of the weight average molecular weight component of 1/5 or less of the Mp value is 24.5%, Mh of 0 to 2% portion from the GPC area high molecular weight side: 4.5%, the GPC area high molecular weight side From 98 to 100%, part Ml: 0.2%.
Composition of the obtained methacrylic resin, weight average molecular weight, molecular weight distribution, peak weight average molecular weight (Mp), abundance of weight average molecular weight component of 1/5 or less of Mp value, 0 from GPC area high molecular weight side Table 7 below shows the Mh in the ˜2% portion and the 98-100% portion Ml from the GPC area high molecular weight side.

(Mixture of methacrylic resin (A) and additive (B))
To 100 parts by mass of the methacrylic resin (A) obtained in Example 17, 5 parts by mass of KTL-20N polytetrafluoroethylene (PTFE) manufactured by Kitamura Co., Ltd. was added as an additive (B). The mixture was melt-kneaded in a twin screw extruder of φ30 mm set at 250 ° C., and the strand was cooled and cut to obtain a resin composition pellet for melt molding.
The blending amounts of the methacrylic resin (A) and the additive (B) are shown in Table 8 below.

  When the processing stability at the time of pellet preparation of the resin composition of Example 17 was evaluated, the strands were hardly cut (evaluation result:）), and the processing stability was very excellent.

Further, when the fluidity of the obtained resin composition pellets was measured by the spiral length, it was 28.0 cm when the injection pressure was 98 MPa at 250 ° C., and the rupture time of the molded body by the cantilever method was It was 1400 s when measured.
Further, the VICAT softening temperature was measured to be 108 ° C., and the Charpy impact strength (without notch) was measured as an impact resistance index to be 32.0 kJ / m ² .

[Examples 18 to 20]
In Example 18, 5 parts by mass of FB-20D manufactured by Denki Kagaku Kogyo Co., Ltd. was added as an additive (B): inorganic filler to the methacrylic resin (A) of Example 17 described above.
In Example 19, 3 parts by mass of Titanium RTC-30 manufactured by Tyoxide Co. as an additive (B): colorant was added to the methacrylic resin (A) of Example 17.
In Example 20, in addition to the methacrylic resin (A) of Example 17, additive (B): Organic rubber particles as SRH manufactured by Asahi Kasei Chemicals Co., Ltd. as organic rubber particles: 3 parts by mass and Kitamura Co., Ltd. KTL-20N polytetrafluoroethylene (PTFE): 2 parts by mass was added.

[Examples 21 to 24 ] , [Reference Example 25], [Examples 26 to 29], [Comparative Examples 10 to 15]
Polymerization was performed in the same manner as in Example 17 using the raw materials shown in Table 5 to obtain polymer fine particles corresponding to Resin A2 to A10 and Resin A11 to A16.
Also, resin composition pellets were prepared in the same manner as in Example 17, and the weight average molecular weight and molecular weight distribution measurement results by GPC, the peak weight average molecular weight (Mp), and the weight average molecular weight component of 1/5 or less of the Mp value. Table 7 shows the abundance (%), Mh of 0 to 2% portion from the GPC area high molecular weight side, and 98 to 100% portion Ml from the GPC area high molecular weight side.
Moreover, the compounding ratio of each methacrylic resin (A) and the additive (B) is shown in the following Tables 8 and 9, and the physical property measurement results of the obtained resin compositions are shown in the following Table 10.

The Charpy impact strength (without notch) of the resin composition of Example 20 was measured and found to be 34.0 kJ / m ² .
Moreover, the break time of the molded article by the cantilever method of the resin composition of Example 28 was 900 s, and the Charpy impact strength (no notch) was 30.0 kJ / m ² .

  In Examples 22-24, since the weight average molecular weight (Mw) and molecular weight distribution Mw / Mn of the methacrylic resin (A) were appropriate, the processing stability was ◎.

In Reference Example 25, the molecular weight distribution (Mw / Mn) was around 3.0, and the processing stability was slightly reduced as compared with Example 18, but this was not a problem in practical use.

In Examples 26 and 27, since it deviates from the following formula (iii) which is a preferable condition of Mh and Ml described in the text of the specification, the processing stability was slightly lowered as compared with Example 18.
8 ≧ (Mh−2) ≧ Ml ≧ 0 (iii)

In Example 28, when polymer (I) was polymerized, methacrylic acid prepared by adding other vinyl monomer copolymerizable with the methacrylic acid ester monomer that satisfies the following condition (ii) System resin (A) was used.
(Mh−0.8) ≧ Ml ≧ 0 (ii)
As a result, a resin composition excellent in processing stability and having a good balance of fluidity, solvent resistance, and heat resistance was obtained.

  In Example 29, the molecular weight distribution (Mw / Mn) was around 5.0, and the processing stability was slightly lowered as compared with other examples.

In Comparative Example 10, since the ratio (%) of the component having a weight average molecular weight (Mw) of 1/5 or less of the peak weight average molecular weight (Mp) was not appropriate, the processing stability was not preferable.
In Comparative Examples 11 and 12, since the weight average molecular weight (Mw) and the molecular weight distribution (Mw / Mn) were not appropriate, the processing stability was not preferable.
In Comparative Example 13, since the weight average molecular weight (Mw) was not appropriate, the strength of the base resin was lowered, and the processing stability was not preferable.
In Comparative Example 14, since the other vinyl monomer unit copolymerizable with the methacrylic acid ester monomer in the composition of the methacrylic resin is 1.0% by mass, the melt viscosity becomes high and the molding processability is high. It was not preferable.
Moreover, in the comparative example 15, since molecular weight distribution (Mw / Mn) = 5.9, the moldability was not preferable.

  A methacrylic resin, a methacrylic resin composition, and a molded product thereof according to the present invention are used in display (device) windows of mobile phones, liquid crystal monitors, liquid crystal televisions, etc., light guide plates used in liquid crystal displays, and front plates of display devices. Foreheads and paintings, windows for taking in external light, display signs, exteriors such as carport roofs, sheets used for exhibition shelves, covers and gloves for lighting fixtures, pressure forming, vacuum forming, blow Used for molded products that have secondary processing such as molding, and especially for tail lamps and headlamps that are thin and large in size and require durability to solvents such as alcohol-based cleaning agents, waxes, and wax removers. There is industrial applicability as a material for various molded products such as vehicular optical parts, washstands, and water-use applications such as resin toilets.

1 Fixing jig 2 Molded body (test piece)
3 Weight 4 Filter paper 5 Octopus thread 6 GPC elution curve (curve connecting RI detection intensity at each elution time)
7 Baseline

Claims (3)

Methacrylic acid ester monomer unit: 80-98.5 mass%,
At least one other vinyl monomer unit copolymerizable with the methacrylic acid ester monomer: 1.5 to 20% by mass;
A methacrylic resin containing
The weight average molecular weight (Mw) is 140000-250,000,
The methacrylic resin contains a weight average molecular weight component of 1/5 or less of the peak weight average molecular weight (Mp) obtained from the GPC elution curve,
The relationship between the weight average molecular weight (Mw) and the number average molecular weight (Mn) satisfies the following formula (i):
In the measurement of the twisting resistance for measuring the generation of the resin yarn when the hot plate having a surface temperature of 390 ° C. is pressed and released, the long yarn generation rate of 5 mm or more is 5% or less.
Methacrylic resin for injection molding .
3.2 ≦ Mw / Mn ≦ 5.5 (i) In the area of the gel permeation chromatography (GPC) elution curve of the methacrylic resin,
Average composition ratio of other vinyl monomer units copolymerizable with the methacrylic acid ester monomer in the methacrylic resin having a weight average molecular weight component having a cumulative area area (%) of 0 to 2%. Mh (mass%),
Average composition ratio Ml of other vinyl monomer units copolymerizable with the methacrylic acid ester monomer in a methacrylic resin having a weight average molecular weight component having a cumulative area area (%) of 98 to 100% ( Mass%),
The methacrylic resin for injection molding according to claim 1, which has a relationship represented by the following formula (ii).
(Mh−0.8) ≧ Ml ≧ 0 (ii) In the area of the gel permeation chromatography (GPC) elution curve of the methacrylic resin,
Average composition ratio of other vinyl monomer units copolymerizable with the methacrylic acid ester monomer in the methacrylic resin having a weight average molecular weight component having a cumulative area area (%) of 0 to 2%. Mh (mass%),
In the methacrylic resin having a weight average molecular weight component having a cumulative area area (%) of 98 to 100%, other vinyl monomer units copolymerizable with the methacrylic acid ester monomer,
Average composition ratio Ml (mass%),
The methacrylic resin for injection molding according to claim 1 or 2, wherein has a relationship represented by the following formula (iii).
8 ≧ (Mh−2) ≧ Ml ≧ 0 (iii)

Images