JP2012087251A - Impact-resistive acrylic resin composition, molded body, and vehicular member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an acrylic resin having high fluidity, processability, impact resistance, solvent resistance and heat resistance.SOLUTION: An acrylic resin composition includes (A) an acrylic resin containing 80 to 99.5 mass% of a methacrylate ester monomer unit and 0.5 to 20 mass% of another vinyl monomer unit copolymerizable with at least one methacrylate ester, and satisfies the following conditions, and (B) a rubbery polymer. (I) The weight-average molecular weight measured by gel permeation chromatography (GPC) is 60,000 to 300,000. (II) Components having a molecular weight of ≤1/5 of a peak molecular weight (Mp) acquired by GPC elution curve account for 7 to 40% as an area ratio acquired by the GPC elution curve.

Description

  The present invention relates to an impact-resistant acrylic resin composition that does not cause molding defects such as jetting during injection molding, and a molded body using the same. The present invention relates to a molded body using the acrylic resin.

  Methacrylic resins represented by polymethyl methacrylate (PMMA) are widely used in the fields of optical materials, automotive parts, building materials, lenses, household goods, OA equipment, lighting equipment, etc. due to their high transparency. ing. 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, and the use of conventional methacrylic resin compositions that makes molding difficult has increased. For example, when injection molding a large, long molded product, a substantially string-like flow trace may occur depending on the flow state of the molten resin. This is generally known as a jetting phenomenon, and is known to some extent by adjusting injection conditions such as injection speed, and adjusting the gate position, gate shape, size, and the like.

  In recent years, especially for vehicle parts, large and long molded bodies such as interior parts such as door trims and visors have been required to be thin from the viewpoint of weight reduction. When the molded body is thinner, more stringent injection conditions are required than before, so jetting is likely to occur, and it is difficult to improve by adjusting injection conditions and injection gate positions that have been taken as usual. It is becoming.

  Therefore, a highly fluid resin that can be molded even at a low injection pressure is desired. On the other hand, while maintaining the colorless transparency of the methacrylic resin and the processability of the obtained resin, it is solvent resistant. Further improvement in mechanical strength is also required.

  Conventionally, a technique for imparting impact resistance without blending a rubbery polymer without impairing transparency is known (Patent Documents 1 and 2). However, no consideration has been given to preventing jetting in a long molded piece, and an acrylic resin composition having high molding processability has been demanded.

Japanese Patent Publication No.55-27576 JP-A-53-58554

  However, the technologies of Patent Documents 1 and 2 have made it possible to impart impact resistance to the resulting acrylic resin composition, but in particular, no consideration has been given to preventing jetting during molding of long molded pieces. There is a need for improvement.

  Therefore, in the present invention, an object is to provide an impact-resistant acrylic resin composition that has high molding processability and impact resistance and does not cause molding defects such as jetting, and a molded body using the same. To do.

As a result of intensive studies to solve the above-described problems of the prior art, the present inventors have found that an acrylic resin composition comprising an acrylic resin having a specific molecular weight characteristic and a rubbery polymer is molded. The present inventors have found that the conventional problems such as suppressing jetting phenomenon during processing can be solved, and have completed the present invention.
That is, the present invention is as follows.

[1] Including 80 to 99.5% by mass of methacrylic acid ester monomer units and 0.5 to 20% by mass of other vinyl monomer units copolymerizable with at least one methacrylic acid ester, An acrylic resin composition characterized by comprising an acrylic resin (A) characterized by satisfaction and a rubbery polymer (B).
I) The weight average molecular weight measured by gel permeation chromatography (GPC) is 60,000 to 300,000,
II) The molecular weight component of 1/5 or less of the peak molecular weight (Mp) obtained from the GPC elution curve is 7 to 40% as the area area ratio obtained from the GPC elution curve.
[2] The acrylic resin composition according to [1], comprising 1 to 200 parts by mass of a rubbery polymer (B) with respect to 100 parts by mass of the acrylic resin (A).
[3] The acrylic resin composition according to any one of [1] to [2], wherein the rubber polymer (B) is an acrylic rubber polymer.
[4] The acrylic resin composition according to any one of claims 1 to 3, wherein the rubbery polymer (B) has a multilayer structure of three or more layers.
[5] The acrylic resin composition according to any one of [1] to [4], wherein the acrylic insoluble part content of the acrylic resin composition is 1 to 65% by mass. [1] A molded product obtained by molding the acrylic resin composition according to any one of [5].
[7] A molded product obtained by injection molding the acrylic resin composition according to any one of [1] to [5].
[8] The molded body according to any one of [6] to [7], which is a vehicle component.

  According to the present invention, an acrylic resin having high moldability, fluidity, and colorless transparency can be obtained.

It is the figure which showed an example of the accumulation area area on a GPC elution curve measurement graph. It is a figure which shows the accumulation area area of the predetermined | prescribed area | region on a GPC elution curve measurement graph. It is a figure which shows the average composition ratio of the high molecular component and low molecular component on the GPC elution curve measurement graph of acrylic resin as a cumulative area area.

Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail.
The present invention is not limited to the following embodiments, and various modifications can be made within the scope of the gist.

In the present invention, the monomer component before polymerization is referred to as “˜monomer”, and “monomer” may be omitted. Moreover, the structural unit which comprises a polymer is called "-monomer unit."
Hereinafter, in this specification, the acrylic resin is described as including a methacrylic resin.

[Acrylic resin (A)]
(composition)
The acrylic resin of the present embodiment is composed of 80 to 99.5% by mass of methacrylic acid ester monomer units, and 0.5 to 20% by mass of other vinyl monomer units copolymerizable with at least one methacrylic acid ester. %, And (I) the weight average molecular weight measured by gel permeation chromatography (GPC) is 60,000 to 300,000, and (II) the peak molecular weight (Mp) obtained from the GPC elution curve is 1 / A molecular weight component of 5 or less satisfies 7 to 40% as an area area ratio obtained from the GPC elution curve.

<Methacrylate monomer>
When the acrylic resin of the present embodiment has the above composition, the methacrylic acid ester monomer constituting this is not particularly limited as long as the effects of the present invention can be achieved. Includes monomers represented by the following general formula (i).

なお、式（i）中、Ｒ_１はメチル基を表す。

In formula (i), 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.
Specific examples of suitable methacrylic acid ester monomers include butyl methacrylate, ethyl methacrylate, methyl methacrylate, propyl methacrylate, isopropyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, methacrylic acid (2-ethylhexyl), Examples thereof include methacrylic acid (t-butylcyclohexyl), benzyl methacrylate, methacrylic acid (2,2,2-trifluoroethyl), and a typical one is methyl methacrylate.

The said methacrylic acid ester monomer may be used individually by 1 type, and may be used in combination of 2 or more type.
Further, in the method for producing an acrylic resin of the present embodiment, which will be described later, even if “polymer (I)” and “polymer (II)” use the same methacrylic acid ester monomer. It is also possible to use different methacrylic acid ester monomers.

<Other vinyl monomers copolymerizable with methacrylic acid ester>
The other vinyl monomer copolymerizable with the methacrylic acid ester is not particularly limited, but an acrylate monomer represented by the following general formula (ii) is preferable. .

Ｒ_３は水素原子であり、Ｒ_４は炭素数が１〜１８のアルキル基である。

R ₃ is a hydrogen atom, and R ₄ is an alkyl group having 1 to 18 carbon atoms.

  Examples of other vinyl monomers copolymerizable with the methacrylic acid ester include α, β-unsaturated acids such as acrylic acid and methacrylic acid; and unsaturated acids such as maleic acid, fumaric acid, itaconic acid, and cinnamic acid. Group-containing divalent carboxylic acids and alkyl esters thereof; styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, 3,4-dimethylstyrene, Styrene monomers such as 3,5-dimethylstyrene, p-ethylstyrene, m-ethylstyrene, о-ethylstyrene, p-tert-butylstyrene, isopropenyl benzene (α-methylstyrene); 1-vinylnaphthalene 2-vinylnaphthalene, 1,1-diphenylethylene, isopropenyltoluene, isopropenylethylben Aromatic vinyl compounds such as ethylene, isopropenylpropylbenzene, isopropenylbutylbenzene, isopropenylpentylbenzene, isopropenylhexylbenzene, isopropenyloctylbenzene; Unsaturated carboxylic acid anhydrides such as itaconic acid; N-substituted maleimides such as maleimide, N-methylmaleimide, N-ethylmaleimide, N-phenylmaleimide and N-cyclohexylmaleimide; 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 Esterylene glycol such as ethylene glycol or its both hydroxyl groups esterified 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 Examples include those esterified with an acid; those obtained by esterifying a polyhydric alcohol derivative such as trimethylolpropane and pentaerythritol with acrylic acid or methacrylic acid; and polyfunctional monomers such as divinylbenzene.

  In addition, in the acrylic resin of the present embodiment, for the purpose of improving particularly required characteristics such as heat resistance, optical characteristics, and workability, a vinyl monomer other than the above-mentioned various materials is appropriately added and copolymerized. You may let them.

For example, from the viewpoint of enhancing light resistance, heat resistance, fluidity, and thermal stability, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, sec-butyl acrylate, 2-ethylhexyl acrylate Etc. are preferably used. Methyl acrylate, ethyl acrylate, and n-butyl acrylate are more preferable, and methyl acrylate is easily available, and more preferable.
The said vinylic monomer may be used individually by 1 type, and may be used in combination of 2 or more types.

  Further, in the method for producing an acrylic resin of the present embodiment to be described later, “polymer (I)” and “polymer (II)” may be those using the same vinyl monomer. A different vinyl monomer may be used.

<Addition amount>
As described above, the acrylic resin of the present embodiment is another vinyl monomer unit copolymerizable with at least one methacrylate ester with respect to 80 to 99.5% by mass of the methacrylate ester monomer unit. 0.5 to 20% by mass, more preferably 0.5 to 15% by mass, still more preferably 0.5 to 10% by mass, even more preferably 0.7 to 8% by mass, and more. More preferably, it contains 1 to 8% by mass, particularly preferably 1 to 6% by mass.
Thereby, the acrylic resin excellent in fluidity | liquidity, heat resistance, and heat stability is obtained.

(Weight average molecular weight)
The acrylic resin of this embodiment needs to have a weight average molecular weight of 60,000 to 300,000 as measured by gel permeation chromatography (GPC). More preferably, it is 60,000 to 250,000, and further preferably 70,000 to 230,000.
Thereby, an acrylic resin excellent in mechanical strength, solvent resistance, and fluidity can be obtained.
For the measurement of the weight average molecular weight, a monodispersed standard methacrylic resin having a known weight average molecular weight and available as a reagent, and an analytical gel column that elutes a high molecular weight component first, and elution time and weight average molecular weight are used. A calibration curve is prepared, and the weight average molecular weight of the measurement sample can be obtained from the obtained calibration curve.

  In addition, the molecular weight distribution (weight average molecular weight / number average molecular weight: Mw / Mn) of the acrylic resin of the present embodiment is 2.1 or more and 7 or less from the viewpoint of balance of fluidity, mechanical strength, and solvent resistance. More preferably, it is 2.1 or more and 6 or less, More preferably, it is 2.2 or more and 5 or less, More preferably, it is 2.2 or more and 4.5 or less.

In addition, the acrylic resin of the present embodiment includes a molecular weight component of 1/5 or less of the peak molecular weight (Mp) obtained from the GPC elution curve in an area area ratio of 7 to 40% in the GPC elution curve. Need to be
Thereby, the improvement of the process fluidity at the time of shaping | molding is achieved, the favorable plasticization effect is acquired, and the distortion suppression of a molded article and the crack suppression effect are acquired. Further, jetting that tends to occur when combined with an acrylic resin or a rubbery polymer can be suppressed.

The content of the molecular weight component of 1/5 or less of the peak molecular weight (Mp) is more preferably 7 to 35%, further preferably 8 to 35%, and still more preferably, in terms of area area ratio in the GPC elution curve. 8-30%.
It should be noted that an acrylic resin having a molecular weight of 500 or less tends to cause a foam-like appearance defect called silver streak at the time of molding.

Here, the peak molecular weight (Mp) refers to the weight average molecular weight showing a peak in the GPC elution curve. When there are a plurality of peaks in the GPC elution curve, it means a peak represented by a molecular weight having the largest abundance.
The content of a molecular weight component equal to or less than 1/5 of the peak molecular weight (Mp) is obtained by calculating an area area in the GPC elution curve.

FIG. 1 shows an example of the accumulated area area on the GPC elution curve measurement graph.
The vertical axis of the graph shows RI (differential refraction) detection intensity (mV), the lower part of the horizontal axis of the graph shows elution time (minutes), and the upper part shows the cumulative area area (%) with respect to the entire GPC area area.
In FIG. 1, the area area in the GPC elution curve indicates a hatched portion.

  Specifically, first, a GPC elution curve obtained from GPC measurement and a GPC elution curve obtained from an RI (differential refraction detector) detection intensity are automatically drawn by a measuring instrument. A point A and a point B at which

Point A is a point where the GPC elution curve 1 and the baseline 2 at the beginning of the elution time intersect.
Point B is a position where the molecular weight is 500 or more and the baseline and the GPC elution curve intersect as a rule. When the molecular weight does not intersect within the range of 500 or more, the value of the RI detection intensity at the elution time when the 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. The area in the area is the area area in 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.

  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 total area area in the GPC elution curve is defined as the value of the accumulated area area (%) at a certain elution time.

  Hereinafter, using the GPC curve of FIG. 3, the average composition ratio of each component of the high molecular weight component and the low molecular weight component of other vinyl monomer units copolymerizable with the methacrylic acid ester in the methacrylic resin, Shown as cumulative area. Let Mh (mass%) be the average composition ratio of other vinyl monomer units that can be copolymerized with a methacrylic acid ester in a methacrylic resin having a cumulative area area of 0 to 2%, that is, a high molecular weight. On the other hand, the average composition ratio of other vinyl monomer units that can be copolymerized with a methacrylic acid ester in a methacrylic resin having a cumulative area of 98 to 100%, that is, a low molecular weight 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%.

The values of Mh and Ml can be determined by continuously collecting several times or several tens of times according to the column size based on the elution time obtained from GPC.
The composition of the sample collected may be analyzed by a known pyrolysis gas chromatography method.

When the acrylic resin of this embodiment is a methacrylic resin using a methacrylic acid ester and a vinyl monomer as a polymerization raw material, Mh (mass%) and Ml (mass%) are represented by the following formula (iii): It is preferable that the relationship holds.
(Mh−0.8) ≧ Ml ≧ 0 (iii)

  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. The low molecular weight component indicates that another vinyl monomer is not necessarily copolymerized.

  The difference between Mh (mass%) and Ml (mass%) is preferably 0.8 mass% or more, more preferably 1.0 mass% or more for the effect of improving fluidity, and further preferably, That is, equation (iv) holds.

(Mh-2) ≧ Ml ≧ 0 (iv)
That is, by increasing the average composition of the high molecular weight component of other vinyl monomer units copolymerizable with the methacrylic ester of the methacrylic resin by 2% by mass or more than the average composition of the low molecular weight component, It is preferable because a dramatic improvement in fluidity can be obtained while maintaining a low incidence of cracks and distortion of molded products and mechanical strength in environmental tests.

(Average particle size)
It is preferable that the acrylic resin average particle diameter of this embodiment is 0.1-10 mm. More preferably, it is 0.1-5 mm, More preferably, it is 0.15 mm-5 mm.
For example, the average particle size was classified using a sieve based on JIS-Z8801, the weight distribution was measured, and the weight distribution was defined as the particle size distribution. From this particle size distribution, it is obtained by calculating a particle size corresponding to 50% by mass as an average particle size.

[Method for producing acrylic resin]
Hereinafter, although the manufacturing method of acrylic resin of this embodiment mentioned above is demonstrated, the manufacturing method of acrylic resin of this embodiment is not limited to the method shown below.

The acrylic resin of this embodiment can be produced by a bulk polymerization method, a solution polymerization method, a suspension polymerization method, or an emulsion polymerization method. A bulk polymerization method, a solution polymerization method and a suspension polymerization method are preferably used, a solution polymerization method and a suspension polymerization method are more preferable, and a suspension polymerization method is more preferably used.
As a specific method for producing the acrylic resin of the present embodiment, for example, the following method may be mentioned.

(First method)
A polymer (I) having a predetermined weight average molecular weight (for example, 5,000 to 50,000) is produced in advance so as to have a predetermined content, and a weight average molecular weight (for example, different from the polymer (I) (for example, Polymer (I) is mixed with a raw material composition mixture of polymer (II) having 60,000-350,000). A method in which the mixed solution is polymerized so that the polymer (II) has a predetermined content.

(Second method)
A polymer (I) having a predetermined weight average molecular weight (for example, 5,000 to 50,000) is produced in advance so as to have a predetermined content, and then, a weight average molecular weight different from this polymer (I) ( For example, the raw material composition mixture of the polymer (II) having 60,000 to 350,000) is sequentially added to the polymer (I), or the polymer (I) is added to the polymer (I) for each polymerization solution. The method of manufacturing by adding to the raw material composition mixture of II) sequentially, and superposing | polymerizing so that polymer (II) may become predetermined | prescribed content.

  The weight average molecular weight of the polymer (I) is a value measured by gel permeation chromatography from the viewpoint of suppressing occurrence of defects such as silver during molding, ensuring polymerization stability, and imparting fluidity. It is preferable that it is 5,000-50,000 like this, More preferably, it is 10,000-50,000, More preferably, it is 20,000-50,000, More preferably, it is 20,000-35,000.

  The weight average molecular weight of the polymer (II) is preferably from 60,000 to 350,000 as described above, more preferably from 70,000 to 320,000, and even more preferably from the viewpoint of mechanical strength and fluidity. 50,000 to 300,000.

  In the polymerization step for producing the acrylic resin of this embodiment, a polymerization initiator may be used for the purpose of adjusting the degree of polymerization of the polymer to be produced.

  As the polymerization initiator, when performing radical polymerization, di-t-butyl peroxide, lauroyl peroxide, stearyl peroxide, benzoyl peroxide, t-butyl peroxyneodecanate, t-butyl peroxypivalate, Dilauroyl peroxide, dicumyl peroxide, t-butylperoxy-2-ethylhexanoate, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis Organic peroxides such as (t-butylperoxy) cyclohexane, azobisisobutyronitrile, azobisisovaleronitrile, 1,1-azobis (1-cyclohexanecarbonitrile), 2,2′-azobis-4 -Methoxy-2,4-azobisisobutyronitrile, 2,2'-azobis- Examples include azo-based general radical polymerization initiators such as 2,4-dimethylvaleronitrile and 2,2'-azobis-2-methylbutyronitrile.

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 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, considering the polymerization temperature and the half-life of the initiator. Can be selected as appropriate.

  When a bulk polymerization method, a cast polymerization method or a suspension polymerization method is selected, it is possible to prevent coloring of the resin, and so on, so that the peroxide initiators lauroyl peroxide, decanoyl peroxide, and t-butylperoxy- 2-ethylhexanoate and the like can be particularly preferably used, and lauroyl peroxide is particularly preferably used.

In addition, when the solution polymerization method is performed at a high temperature of 90 ° C. or higher, a peroxide, an azobis initiator, or the like that has a 10-hour half-life temperature of 80 ° C. or higher and is soluble in the organic solvent to be used is preferable. 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.
These initiators are preferably used, for example, 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.

In the polymerization step for producing the acrylic resin of this embodiment, the molecular weight of the polymer to be produced can be controlled.
For example, the molecular weight can be controlled by using chain transfer agents such as alkyl mercaptans, dimethylacetamide, dimethylformamide, and triethylamine, and iniferters such as dithiocarbamates, triphenylmethylazobenzene, and tetraphenylethane derivatives.

The molecular weight can be adjusted by adjusting the amount of these additives.
When these additives are used, alkyl mercaptans are preferably used from the viewpoint of handleability and stability. For example, n-butyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-tetra Examples include decyl mercaptan, n-octadecyl mercaptan, 2-ethylhexyl thioglycolate, ethylene glycol dithioglycolate, trimethylolpropane tris (thioglycolate), pentaerythritol tetrakis (thioglycolate) and the like.

These can be appropriately added according to the required molecular weight, but generally used in the range of 0.001 to 3 parts by mass with respect to 100 parts by mass of the total amount of all monomers used. .
Other molecular weight control methods include a method of changing the polymerization method, a method of adjusting the amount of the polymerization initiator, and a method of changing the polymerization temperature.
These molecular weight control methods may be used alone, or two or more methods may be used in combination.

  The polymerization temperature may be appropriately selected depending on the polymerization method, and is preferably 50 ° C. or higher and 200 ° C. or lower. The relationship between the polymerization temperature and the holding time in the case of producing an acrylic resin by applying the above (first method) and (second method) will be described later.

  The above-described method is a method for producing an acrylic resin containing two types of polymer (I) and polymer (II) components having different weight average molecular weights. However, the present invention is not limited to this example, and an acrylic resin containing polymers having different weight average molecular weights may be produced by the same operation.

The method for producing the polymer (II) in the state where the polymer (I) is produced and the polymer (I) is present in the raw material composition mixture of the polymer (II) is the present embodiment. This is a preferable method for producing the acrylic resin.
This method is preferable because the compositions of the polymer (I) and the polymer (II) can be easily controlled, the temperature rise due to heat generated during polymerization can be suppressed, and the viscosity in the system can be stabilized.

  In this case, the raw material composition mixture of the polymer (II) may be in a state where the polymerization is partially started. As a polymerization method therefor, any one of bulk polymerization, solution polymerization, suspension polymerization, or emulsion polymerization is preferable, and bulk polymerization, solution polymerization, and suspension polymerization are more preferable.

<Blending ratio of polymers (I) and (II)>
Next, regarding the method for producing the acrylic resin of the present embodiment, specific blending ratios of the above-described polymers (I) and (II) will be described.
In the following description, the polymers (I) and (II) are both methacrylic acid ester-based polymers containing a methacrylic acid ester monomer as a polymerization raw material.

  In both the above (first method) and (second method), the methacrylic acid ester monomer, or the methacrylic acid ester monomer and at least one kind of methacrylic acid ester are combined in the first stage polymerization step. By polymerizing another polymerizable vinyl monomer, a methacrylic acid ester polymer (polymer (I)) is obtained. In the second stage polymerization step, the methacrylic acid ester monomer or the methacrylic acid ester monomer And a methacrylic ester polymer (polymer (II)) obtained by polymerizing another vinyl monomer copolymerizable with at least one methacrylic ester.

These compounding ratios are polymer (I): 5-45 mass%, and it is preferable that it is polymer (II) 95-55 mass%.
By setting it as such a compounding ratio, the polymerization stability in a manufacturing process can be aimed at, and it is preferable also from a viewpoint of the fluidity | liquidity of a methacrylic resin, a moldability, and mechanical strength. In order to further improve the balance of these characteristics, the ratio of polymer (I) / polymer (II) is more preferably 5 to 40% by mass / 95 to 60% by mass, and more preferably 5 to 35% by mass. % / 95 to 65% by mass is more preferable, and 10 to 35% by mass / 90 to 65% by mass is even more preferable.

  As a raw material for the polymer (I), when other vinyl monomers are added to the methacrylic acid ester monomer, the composition ratio of the methacrylic acid ester monomer to the other vinyl monomer is The vinyl monomer is preferably 20 to 0% by mass with respect to 80 to 100% by mass of the acid ester monomer, and more preferably the composition ratio of methacrylic acid ester monomer / other vinyl meter monomer. Then, it is 90-100 mass% / 10-0 mass%, More preferably, it is 95-100 mass% / 5-0 mass%.

  When it is particularly necessary to consider the polymerization stability, the blending amount of other vinyl monomers copolymerizable with the methacrylic acid ester monomer in the polymer (I) is substantially zero. In this case, the amount of the methacrylic acid ester monomer as a raw material is allowed to be present as an impurity.

  When other vinyl monomer is added to the methacrylic acid ester monomer that is the raw material of the polymer (II), the composition ratio of the methacrylic acid ester monomer to the other vinyl monomer is methacrylic acid. The composition ratio of ester monomer / other vinyl monomer is preferably 80 to 99.5% by mass / 20 to 0.5% by mass, and 85 / 99.5% by mass / 15 to 0%. More preferably, the content is 0.5 mass%, more preferably 88 to 99 mass% / 12 to 1 mass%, and even more preferably 90 to 98.5 mass% / 10 to 1.5 mass%. preferable.

<Copolymerization ratio of vinyl monomer in polymer (I) and vinyl monomer in polymer (II)>
Each of the polymers (I) and (II) of the “other vinyl monomer units copolymerizable with a methacrylic acid ester” that can be used as a raw material for the polymer (I) and the polymer (II). The copolymerization ratio is not particularly limited as long as the effects of the present invention can be exhibited, but other vinyl monomer units copolymerizable with the methacrylic acid ester of the polymer (I). From the viewpoint of polymerization stability, when the composition ratio of Mal (mass%) and the composition ratio of other vinyl monomer units copolymerizable with the methacrylic acid ester of the polymer (II) is Mah (mass%), It is preferable that the relationship of the following formula (v) is established.
Mah ≧ Mal ≧ 0 (v)

Higher molecular weight polymer (II) contains more vinyl monomer copolymerizable with methacrylic acid ester as a composition ratio, so that polymerization stability can be achieved and heat resistance can be improved. The fluidity can be improved while maintaining the properties and mechanical strength, which is preferable.
More preferably, the relationship of the following formula (vi) is satisfied.
(Mah-0.8) ≧ Mal ≧ 0 (vi)

In the acrylic resin of the present embodiment, when a molded body is used, it is required to improve the fluidity while maintaining the mechanical strength while reducing the occurrence rate of cracks and distortion of molded products in the environmental test. It is preferable to satisfy the relationship of vii).
(Mah-2) ≧ Mal ≧ 0 (vii)

The composition ratio (Mal) of other vinyl monomer units copolymerizable with the methacrylic acid ester of the polymer (I) and other vinyl monomers copolymerizable with the methacrylic acid ester of the polymer (II). The amount of the composition ratio (Mah) of the unit is determined by measuring and determining the polymer (I) and the polymer (II) by pyrolysis gas chromatography.
In order to satisfy the above formulas, the respective composition ratios Mal and Mah are prepared by adjusting the amount of other vinyl monomers copolymerizable with the methacrylic acid ester monomer added during polymerization. do it.

(Manufacturing method of acrylic resin by suspension polymerization method)
In the acrylic resin production method of the present embodiment, the case where the polymerization process is carried out by applying the suspension polymerization method will be described in detail.
When the acrylic resin is produced by suspension polymerization, the polymer (II) is polymerized in the presence of the polymer (I) in the above-described (first method) and (second method).

<Temperature and time>
When the acrylic resin is polymerized by suspension polymerization, the polymerization temperature is preferably 60 ° C. or higher and 90 ° C. or lower and 65 ° C. or higher and 85 ° C. or lower from the viewpoint of productivity and the amount of aggregates produced. Is more preferably 70 ° C. or more and 85 ° C. or less, and further preferably 70 ° C. or more and 83 ° C. or less.
The polymerization temperatures of the polymer (I) and the polymer (II) described above may be the same or different.

  The time (T1) from the addition of the raw material mixture of the polymer (I) to the arrival of the exothermic peak temperature due to the polymerization exotherm is not particularly limited, but is preferably 20 minutes to 240 minutes, More preferably, it is 30 minutes or more and 210 minutes or less, more preferably 45 minutes or more and 180 minutes or less, even more preferably 60 minutes or more and 150 minutes or less, and even more preferably 60 minutes or more and 120 minutes or less. Even more preferred. The polymerization time (T1) may be appropriately adjusted by changing the amount of polymerization initiator used and the polymerization temperature.

  The temperature at which the raw material mixture of the polymer (I) is added may be the same as or lower than the boiling point of the raw material to be used, considering the boiling point of the raw material to be used. Specifically, the temperature is preferably 60 ° C. or higher and 90 ° C. or lower, more preferably 60 ° C. or higher and 85 ° C. or lower, further preferably 65 ° C. or higher and 85 ° C. or lower, and 65 ° C. or higher and 80 ° C. or lower. More preferably, it is more preferably 70 ° C. or higher and 80 ° C. or lower.

  The raw material mixture of the polymer (II) may be added immediately after an exothermic peak due to the polymerization of the polymer (I) is observed, or may be added after holding for a certain time. When it is necessary to increase the degree of polymerization of the raw material mixture of the polymer (I), after the exothermic peak due to the polymer (I) is confirmed, the raw material mixture of the polymer (II) is held for a certain period of time. Is preferably introduced.

  The holding time is preferably 180 minutes or less, more preferably 10 minutes or more and 180 minutes or less, still more preferably 15 minutes or more and 150 minutes or less, still more preferably 20 minutes or more and 120 minutes or less, and even more preferably 20 minutes. It is 90 minutes or less.

  Since the polymerization temperature can be increased, the temperature at the time of holding is preferably the same as the polymerization temperature of the polymer (I) or higher than the polymerization temperature of the polymer (I), and is set to a higher temperature. In this case, it is preferable to raise the temperature by 5 ° C. or more from the polymerization temperature. When the temperature is raised, the temperature is preferably 100 ° C. or lower from the viewpoint of preventing aggregation of the resulting polymer. Specifically, 80 ° C. or higher and 100 ° C. or lower is preferable, 80 ° C. or higher and 99 ° C. or lower is more preferable, 85 ° C. or higher and 99 ° C. or lower is further preferable, 88 ° C. or higher and 99 ° C. or lower is even more preferable, Is even more preferable.

By performing polymerization according to the polymerization temperature and polymerization time described above, polymer particles having a smaller angle of repose can be generated.
As described above, when the temperature is raised in the holding step, from the viewpoint of preventing volatilization of the raw material mixture of the polymer (II), the temperature is lowered to around 70 ° C. to 85 ° C., and then the raw material mixture of the polymer (II) is changed. It is preferable to add.

  The time (T2) from when the raw material mixture of the polymer (II) is added until the exothermic peak temperature due to the polymerization exotherm is observed is not particularly limited, but is preferably 30 minutes or more and 240 minutes or less. More preferably, they are 45 minutes or more and 210 minutes or less, More preferably, they are 60 minutes or more and 210 minutes or less, More preferably, they are 60 minutes or more and 180 minutes or less, More preferably, they are 80 minutes or more and 150 minutes or less.

The relationship between the polymerization times of the polymer (I) and the polymer (II) is such that the polymer (I) can be obtained from the viewpoint that productivity and an acrylic resin having a small difference in weight average molecular weight for each particle diameter can be obtained. Polymerization time, that is, the time (T1) until the exothermic peak temperature is reached due to polymerization exotherm after addition of the monomer in the first stage polymerization, and the polymerization time of the polymer (II), that is, a single amount after the second stage. It is preferable that the following formula (3) holds for the time (T2) to reach the exothermic peak temperature due to polymerization exotherm after adding the body.
0.6 <T2 / T1 (3)

  In particular, when it is necessary to obtain polymer particles having a uniform molecular weight distribution and further to suppress the formation of aggregates that contribute to a decrease in yield, 0.6 <T2 / T1 ≦ 5. More preferably, 1 ≦ T2 / T1 ≦ 5, still more preferably 1 ≦ T2 / T1 ≦ 4, and particularly preferably 1 ≦ T2 / T1 ≦ 3.

  In order to adjust the time required to reach the first and second exothermic peak temperatures so as to satisfy the above formula (3), the polymerization ratio of the polymer (I) and the polymer (II) is adjusted. The polymerization temperature may be adjusted, or the amount of the polymerization initiator to be used may be appropriately adjusted.

  After the exothermic peak temperature due to the polymerization exotherm is observed after the addition of the polymer (II) raw material mixture, the amount of residual monomer in the resulting acrylic resin (methacrylic resin) can be suppressed. It is preferable to raise the temperature by 5 ° C. or more than the polymerization temperature of (II). More preferably, the temperature is raised to 7 ° C or higher, more preferably 10 ° C or higher.

  Moreover, in order to prevent aggregation of the obtained resin, it is preferable that the reached temperature is 100 ° C. or lower, and a preferable temperature range is 85 ° C. or higher and 100 ° C. or lower, more preferably 88 ° C. or higher and 99 ° C. or lower. Preferably they are 90 degreeC or more and 99 degrees C or less.

  The time for maintaining the temperature after the temperature rise is preferably 15 minutes or more and 360 minutes or less, more preferably 30 minutes or more and 240 minutes or less, and more preferably 30 minutes or more and 180 minutes in consideration of the residual monomer reduction effect. More preferably, it is 30 minutes or more and 150 minutes or less, and more preferably 30 minutes or more and 120 minutes or less.

<Washing method>
The obtained polymer slurry is preferably subjected to operations such as acid washing, water washing and alkali washing for removing the suspending agent, and the number of times these washing operations are carried out depends on work efficiency and suspending agent removal efficiency What is necessary is just to choose the optimal number, and it may be repeated once or several times.

What is necessary is just to select the temperature at the time of washing | cleaning in consideration of the removal efficiency of a suspension agent, the coloring degree of the polymer obtained, etc., and it is preferable that it is 20-100 degreeC. More preferably, it is 30-95 degreeC, More preferably, it is 40-95 degreeC.
Moreover, it is preferable that the washing | cleaning time per time at the time of washing | cleaning is 10 to 180 minutes from a viewpoint of washing | cleaning efficiency, a repose angle reduction effect, and the simplicity of a process, More preferably, it is 20 to 150 minutes.

  The pH of the cleaning solution used at the time of the cleaning may be within a range where the suspension can be removed, but is preferably pH 1-12. The pH for acid washing is preferably pH 1-5, more preferably pH 1.2-4, from the viewpoint of the removal efficiency of the suspending agent and the color tone of the resulting polymer.

  The acid used at that time is not particularly limited as long as it can remove the suspending agent. Conventionally known inorganic acids and organic acids can be used. As an example of the acid that is preferably used, the inorganic acid includes hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, boric acid and the like, and each may be used in a diluted solution diluted with water or the like. Examples of the organic acid include those having a carboxyl group, a sulfo group, a hydroxy group, a thiol group, or an enol. Considering the effect of removing the suspending agent and the color tone of the resulting resin, more preferred are nitric acid, sulfuric acid, and organic acids having a carboxyl group.

After the acid cleaning, it is preferable to further perform water washing or alkali washing from the viewpoint of reducing the color tone and angle of repose of the polymer obtained.
The pH of the alkaline solution when performing alkali cleaning is preferably pH 7.1 to 12, more preferably 7.5 to 11, and still more preferably 7.5 to 10.5.

  As the alkaline component used for alkali cleaning, tetraalkylammonium hydroxide, alkali metal hydroxide, alkaline earth metal hydroxide, and the like are preferably used. More preferred are alkali metal hydroxides and alkaline earth metal hydroxides, and further preferred are lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, magnesium hydroxide, calcium hydroxide, Barium hydroxide is more preferable, and lithium hydroxide, sodium hydroxide, potassium hydroxide, magnesium hydroxide, and calcium hydroxide are more preferable, and sodium hydroxide and potassium hydroxide are still more preferable. These alkaline components can be used by adjusting the pH by diluting with water or the like.

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

<Drying process>
The polymer in a water-containing state obtained through the dehydration step can be recovered after being dried by a known method.
For example, hot air drying for drying by sending hot air into the tank from a hot air blower or blow heater, etc., vacuum drying for drying by heating as necessary after reducing the pressure inside the system, and obtained polymer For example, barrel drying for removing moisture by rotating the container in a container, spin drying for drying using centrifugal force, and the like. These methods may be used alone or in combination.

<Average particle diameter of resin obtained by suspension polymerization>
When the acrylic resin (A) in the present embodiment is obtained by the suspension polymerization method, the average particle diameter is preferably 100 to 500 μm from the viewpoint of handleability and color tone. More preferably, it is 150-500 micrometers, More preferably, it is 150-450 micrometers, More preferably, it is 180-450 micrometers, More preferably, it is 200-450 micrometers.

For example, the average particle size is classified using a sieve based on JIS-Z8801, the weight distribution is measured, a particle size distribution is created with the weight distribution, and particles corresponding to 50% by mass from this particle size distribution are prepared. It is obtained by calculating the diameter as the average particle diameter.
Examples of the shape of the acrylic resin (A) include a columnar shape, a substantially spherical shape, and a tablet shape, and a substantially spherical shape is preferable from the viewpoint of handleability and uniformity.

  When the acrylic resin (A) in the present embodiment contains a large amount of fine particles of 0.15 mm, it tends to float in the air at the time of handling, and thus the handleability may be deteriorated. In particular, when handling is excellent, it is preferable to reduce the content of such fine particles. However, when all the fine particles of less than 0.15 mm are removed, the number of removal steps increases, leading to an increase in cost, which is allowed to some extent.

  From the above viewpoint, the content of the component having a particle size of less than 0.15 mm is preferably 0.01% by mass or more and 10% by mass or less, more preferably 0.1% by mass or more and 10% by mass or less, More preferably, they are 0.1 mass% or more and 8 mass% or less, More preferably, they are 0.2 mass% or more and 7 mass% or less, More preferably, they are 0.3 mass% or more and 6 mass% or less. The content of the component less than 0.15 mm is based on JIS-Z8801, JTS-200-45-33 (aperture 500 μm), 34 (aperture 425 μm), 35 (aperture 355 μm), 36 (manufactured by Tokyo Screen) Using a sieve tester TSK B-1 with a mesh opening of 300 μm), 37 (aperture 250 μm), 38 (aperture 150 μm), 61 (a saucer), sieved with a vibration force MAX for 10 minutes. Sometimes it is determined by dividing the amount remaining in the pan by the amount screened.

<Moisture content>
The water content of the obtained resin is preferably 0.01% by mass to 1% by mass, more preferably 0.02% by mass to 0.9% by mass, from the viewpoints of handleability, color tone, and the like. It is more preferable that it is 0.05 mass%-0.8 mass%, and it is still more preferable that it is 0.05 mass%-0.7 mass%.
The water content of the resin can be measured using the Karl Fischer method.

<Aggregates>
As described above, when an acrylic resin is produced using a suspension polymerization method, the resulting resin is substantially spherical, but an aggregate may be formed in part.
When aggregates remain in the resin, the color tone of the resin tends to decrease.
Therefore, the amount of aggregates when passed through a 1.68 mm mesh sieve is preferably 1.2% by mass or less, and more preferably 1.0% by mass or less.

[Rubber polymer (B)]
The rubbery polymer (B) is not particularly limited as long as it can exert the effects of the present application, but rubber particles having a multilayer structure such as general butadiene-based ABS rubber, acrylic-based, polyolefin-based, silicone-based, and fluororubber. Can be used. When high transparency is required, a rubbery polymer having a refractive index close to that of the acrylic resin (A) can be suitably used, and an acrylic rubbery polymer can be particularly suitably used. Specific examples of the rubber polymer (B) suitably used in the present embodiment include the following acrylic rubber polymers.

Example 1 (Japanese Patent Publication No. 60-17406):
“(A) A dispersion of a polymer mainly composed of methyl methacrylate having a glass transition point of 25 ° C. or higher by emulsion polymerization of methyl methacrylate alone or a mixture of methyl methacrylate and a monomer copolymerizable therewith. Forming a first layer,
(B) When this product is polymerized alone, it forms a copolymer having a glass transition point of 25 ° C. or lower, and is mainly composed of an alkyl acrylate, and further, a monomer and polyfunctionality copolymerizable therewith. A second layer step of emulsion polymerization by adding at least one of a crosslinking agent and a mixture containing 0.1 to 5% by weight of a polyfunctional grafting agent based on the total weight of the mixture, and (C) this product alone. A polymer having a glass transition point of 25 ° C. or higher when polymerized is formed, and a chain transfer agent is gradually increased to methyl methacrylate or a monomer mixture mainly composed of this, and emulsion polymerization is performed in multiple stages. A method for producing a multilayer structure acrylic resin molding material comprising a three-layer forming step, wherein the molecular weight of the third layer gradually decreases from the inside toward the outside. Multilayer structure particles made of acrylic rubber obtained by

Example 2 (JP-A-8-245854):
“At least one soft polymer layer containing a polymer having a polymer melting start temperature of 235 ° C. or higher and a glass transition temperature Tg of 25 ° C. or lower when polymerized alone in the inner layer, and in the outermost layer alone Acrylic multilayer structure polymer powder comprising a coagulated powder obtained by coagulating an emulsion latex of an acrylic multilayer structure polymer having a hard polymer layer containing a polymer having a Tg of 50 ° C. or higher when polymerized in The proportion of fine powder having a particle size of 212 μm or less after drying is 40% by weight, and the pore volume measured by mercury intrusion method of the solidified powder after drying is 0.7 cc or less per unit area. An acrylic multilayer structure polymer powder. "

Example 3 (Japanese Patent Publication No. 7-68318):
“(A) 90 to 99% by weight of methyl methacrylate, 1 to 10% by weight of alkyl acrylate having 1 to 8 carbon atoms in the alkyl group, and allyl, methallyl of α, β-unsaturated carboxylic acid copolymerizable therewith, Or innermost hard layer polymer 25 to 45% by weight obtained by polymerizing a monomer mixture consisting of 0.01 to 0.3% by weight of at least one graft-bonding monomer selected from crotyl ester,
(B) In the presence of the innermost hard layer polymer, 70 to 90% by weight of n-butyl acrylate, 10 to 30% by weight of styrene, and allyl, methallyl of α, β-unsaturated carboxylic acid copolymerizable therewith, Or 35 to 45% by weight of a soft layer polymer obtained by polymerizing a monomer mixture consisting of 1.5 to 3.0% by weight of a graft-bondable monomer consisting of at least one selected from crotyl esters,
(C) In the presence of the polymer composed of the innermost hard layer and the soft layer, a monomer mixture obtained by polymerizing 90 to 99% by weight of methyl methacrylate and 1 to 8 carbon atoms of the alkyl group is obtained. The outer hard layer polymer is composed of 20 to 30% by weight,
(D) The weight ratio of soft layer polymer / (innermost hard layer polymer + soft layer polymer) is 0.45 to 0.57,
(E) A multilayer structure acrylic polymer having an average particle size of 0.2 to 0.3 μm, and when the multilayer structure acrylic polymer is further fractionated with acetone,
(F) The graft ratio is 20 to 40% by weight,
(G) A “multilayer structure acrylic polymer”, wherein the acetone-insoluble portion has a tensile modulus of 1000 to 4000 kg / cm 2.

  Other examples of acrylic rubber particles having a three-layer to four-layer structure include Japanese Patent Publication No. 55-27576, Japanese Patent Publication No. 58-1694, Japanese Patent Publication No. 59-36645, Japanese Patent Publication No. 59-36646, and Japanese Patent Publication No. 62. -41241, JP-A-59-202213, JP-A-63-27516, JP-A-51-129449, JP-A-52-56150, application S50-124647, etc. Acrylic rubber particles can also be used.

[Layer structure of rubbery polymer]
As the number of layers of the rubbery polymer (B) is larger, it is possible to obtain a rubbery polymer whose elasticity is controlled within a suitable range, but from the viewpoint of production cost, Particles having a multilayer structure of three layers or more are preferable, and acrylic rubber particles having a multilayer structure of three layers or more are more preferable. By using rubber particles having a multilayer structure of the above three or more layers as the rubber polymer (B), thermal deterioration during molding processing and deformation of the rubber polymer (B) due to heating are suppressed, and molding is performed. The heat resistance and transparency of the body tend to be maintained.

  The rubbery polymer (B) having a multilayer structure of three or more layers means a rubber particle having a multilayer structure in which a soft layer made of a rubbery polymer and a hard layer made of a glassy polymer are laminated, preferably It is a particle having a three-layer structure formed in the order of hard layer-soft layer-hard layer from the inside. By having a hard layer in the innermost layer and the outermost layer, deformation of the rubbery polymer (B) tends to be suppressed, and by having a soft component in the central layer, good toughness tends to be imparted.

  In the multilayer structure graft copolymer composed of three layers, monomers copolymerizable with methyl methacrylate include known (meth) acrylic acid, (meth) acrylates other than methyl methacrylate, styrene, α-methyl Monofunctional monomers such as styrene, ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, Polyfunctional monomers such as triallyl isocyanurate, diallyl maleate, and divinylbenzene are listed. The said monomer can be used 1 type or in combination of 2 or more types as needed.

  The second layer of the multilayer structure graft copolymer composed of three layers is a rubber-like copolymer exhibiting rubber elasticity and is important for imparting excellent impact strength to the cast plate.

  The alkyl acrylate that forms the second layer is not particularly limited, and for example, one or two or more of methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, and the like can be used. Among these, n-butyl acrylate and 2-ethylhexyl acrylate are preferable.

  Further, other monomers copolymerizable with these alkyl acrylates are not particularly limited, and general monomers can be used. However, the acrylic resin can be adjusted by adjusting the refractive index of the second layer. From the viewpoint of improving transparency by adjusting to (A), styrene or a derivative thereof is preferably used.

  When the rubbery polymer (B) in the present embodiment is composed of three layers, the rubbery polymer having a crosslinked structure contained in the rubbery polymer refers to this second layer, It means a rubber-like polymer in which a crosslinked structure is formed by copolymerizing a monomer.

  The cross-linked structure in the rubber-like polymer is necessary for imparting appropriate rubber elasticity and maintaining its form in a dispersed state without dissolving in the monomer mixture.

  As the polyfunctional monomer for forming the crosslinked structure, compounds exemplified as those copolymerizable with methyl methacrylate and methyl acrylate can be used, and the amount used is 0 with respect to the entire second layer. .1 to 5% by mass. When the amount of the polyfunctional monomer used is less than 0.1% by mass, a sufficient crosslinking effect cannot be obtained, and when it exceeds 5% by mass, the crosslinking is too strong, both of which are preferable because the rubber elastic effect is reduced. Absent. Further, if the amount used is less than 0.1% by mass, the rubbery polymer is dissolved or greatly swelled in the cast polymerization step described later, which is not preferable because the rubber elastic body cannot be maintained.

  Furthermore, a polyfunctional grafting agent for forming a graft bond that closes the affinity with the polymer of the third layer is used for the second layer.

  The polyfunctional grafting agent is a polyfunctional monomer having different functional groups, and examples thereof include allyl esters such as acrylic acid, methacrylic acid, maleic acid, and fumaric acid. Among them, allyl acrylate and allyl methacrylate are exemplified. preferable. The usage-amount of a polyfunctional grafting agent is the range of 0.1-3 mass% with respect to the whole 2nd layer. If the amount of the polyfunctional grafting agent used is less than 0.1% by mass, a sufficient graft effect cannot be obtained, and if it exceeds 3% by mass, the rubber elasticity is lowered, which is not preferable.

  In the polymerization of the third layer, the molecular weight can be adjusted using a chain transfer agent in order to improve the affinity with the acrylic resin (A).

  In order to improve the transparency of the acrylic resin composition, it is necessary to match the refractive indexes of the dispersed rubber polymer (B) and acrylic resin (A). It is extremely difficult to completely match the refractive index of the second layer, which is a copolymer having a main component, with the acrylic resin (A). In order to match the refractive index, for example, in the second layer, when alkyl acrylate and styrene or its derivatives are copolymerized, the refractive index becomes substantially equal in a certain temperature range and the transparency is improved. A refractive index shift occurs and transparency is deteriorated.

  As a means for avoiding this, it is possible to provide a first layer whose refractive index is substantially the same as that of the acrylic resin. When there is no first layer, the transparency tends to be remarkably lowered. Further, reducing the thickness of the second layer is also effective in preventing the deterioration of transparency.

  The rubbery polymer (B) in the present embodiment is preferably obtained by emulsion polymerization. Specifically, when the rubbery polymer (B) is composed of three layers, the first monomer mixture is first added in the presence of an emulsifier and an initiator to complete the polymerization. A rubbery polymer (particles) can be easily obtained as a latex by adding a monomer mixture in the first layer to complete the polymerization, and then adding a monomer mixture in the third layer to complete the polymerization. Can do.

The rubbery polymer (particles) can be recovered from the latex as a powder by a known method such as salting out, spray drying, freeze drying and the like.
When the rubber polymer (B) is a polymer composed of three layers, aggregation of the powders can be avoided by providing a hard resin component in the third layer.

[Average particle diameter of rubbery polymer]
Moreover, it is preferable that the average particle diameter of a rubber-like polymer (B) is 0.05-1 micrometer. More preferably, it is 0.05 micrometer-0.7 micrometer, More preferably, it is 0.05 micrometer-0.5 micrometer, Especially preferably, it is 0.05 micrometer-0.4 micrometer, Most preferably, it is 0.05 micrometer-0.3 micrometer. If the average particle size of the rubber polymer is less than 0.05 μm, sufficient impact strength tends to be difficult to obtain, and if it exceeds 1 μm, a certain amount or more (amount at which the acetone insoluble part is 65% by mass or more) )) Is not expressed as a rubber elastic body, or the specularity is hindered by the appearance of fine ripples on the surface of the molded article made of the finally obtained acrylic resin composition, Furthermore, when it is molded by heating, there is a possibility that defects such as a significant decrease in surface gloss at the stretched portion and loss of transparency may occur.

  As a method for measuring the average particle size of the rubbery polymer (B), a conventionally known method can be used, but specific examples of suitable measuring methods include the following methods.

(1) A part of a molded piece made of an acrylic resin composition was cut out with a circular saw, and then a sample for observation by a RuO ₄ (ruthenic acid) -stained ultrathin section method was prepared, manufactured by Hitachi, Ltd. Transmission electron microscope model: Take a picture after observing the cross section of the rubber particles dyed using H-600 type. The average particle diameter of rubber particles is obtained by measuring the diameter of 20 representative particles printed at a high magnification on a scale and obtaining the average value of the diameters of the particles.

(2) A rubber polymer emulsion is sampled, diluted with water to a solid content of 500 ppm, and the absorbance at a wavelength of 550 nm is measured using a UV 1200 V spectrophotometer (manufactured by Shimadzu Corporation). From this value, an average particle diameter is obtained using a calibration curve prepared by measuring the absorbance in the same manner for a sample whose particle diameter was measured from a transmission electron micrograph. In the above specific examples, almost the same particle diameter measurement value can be obtained.

(Amount of acrylic resin and rubber polymer)
The acrylic resin composition of the present embodiment is composed of an acrylic resin (A) and a rubbery polymer (B).
In the present invention, in consideration of fluidity, impact resistance, and mechanical properties, the blending amount of the acrylic resin (A) and the rubbery polymer (B) is rubbery with respect to 100 parts by mass of the acrylic resin (A). It is preferable that a polymer (B) is 1-200 mass parts. More preferably, it is 1-150 mass part, More preferably, it is 1-120 mass part, Most preferably, it is 5-100 mass part.

(Abundance of rubbery polymer in acrylic resin composition)
The abundance of the rubbery polymer in the acrylic resin composition of the present embodiment can be determined by measuring the amount of the acetone insoluble part.
That is, a portion of the acrylic resin composition pellet or molded piece is precisely weighed (W1) and placed in a centrifuge tube, and then acetone is added and dissolved to remove the acetone soluble portion. The solvent is removed in a vacuum dryer and cooled, and the weighed residue is defined as an acetone insoluble part (W2).

The blending amount of the acrylic rubber particles and the acetone-insoluble part do not match, and even if the rubber particle structure (outermost hard layer: dissolved in acetone) is different even with the same size, the physical properties obtained are different, contributing to impact resistance. The rubbery polymer (B) was defined as the acetone insoluble part.
The acetone insoluble part (% by weight) (X) is calculated by the following formula.
Acetone insoluble part (X) = W2 / W1 × 100

  The acetone insoluble part content in the methacrylic resin of the present invention is 1 to 65% by mass in consideration of optical properties [(total light transmittance, haze (cloudiness value)], fluidity, impact resistance, and mechanical strength. More preferably, it is 1-60 mass% of acrylic resin (A), More preferably, it is 1-54 mass%, Most preferably, it is 4-50 mass%.

(Refractive index of acrylic resin (A) and rubber polymer (B))
In the acrylic resin composition of the present embodiment, from the viewpoint of high transparency, transparency, particularly transparency temperature dependency, the refractive index of the acrylic resin (A) and rubber It is preferable that the difference with the refractive index of a quality polymer (B) is 0.015 or less, More preferably, it is 0.012 or less, More preferably, it is 0.01 or less.

<Combination of acrylic resin composition with other resins and additives>
The acrylic resin composition of the present embodiment can be used as a composition in combination with a predetermined other resin and a predetermined additive described later.

<Other resins>
The resin to be combined is not particularly limited, and known curable resins and thermoplastic resins are preferably used.

  For example, thermoplastic resins include polypropylene resin, polyethylene resin, polystyrene resin, syndiotactic polystyrene resin, ABS resin, acrylic resin, AS resin, BAAS resin, MBS resin, AAS resin, raw resin Decomposable 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 because the effect of improving the fluidity of the resin composition is obtained, ABS resin and MBS resin are preferable for improving impact resistance, and polyester resin has chemical resistance. It is preferable for improvement. In addition, polyphenylene ether resins, polyphenylene sulfide resins, phenol resins, and the like can be expected to have an 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 resins.

<Additives>
A predetermined additive may be added to the acrylic resin composition of this embodiment in order to impart various properties such as rigidity and dimensional stability.

  Additives include, for example, various stabilizers such as antioxidants, ultraviolet absorbers, heat stabilizers, light stabilizers; plasticizers (paraffinic process oil, naphthenic process oil, aromatic process oil, paraffin, organic Polysiloxane, mineral oil), flame retardants (eg, phosphorus compounds such as organic phosphorus compounds, red phosphorus, inorganic phosphates, halogens, silicas, silicones, etc.), flame retardant aids (eg, antimony oxides) , Metal oxides, metal hydroxides, etc.), curing agents (diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, diethylaminopropylamine, 3,9-bis (3-aminopropyl) -2,4, 8,10-tetraoxaspiro [5,5] undecane, mensendiamine, isophoronediamine, N-amino Amines such as ethylpiperazine, m-xylenediamine, m-phenylenediamine, diaminophenylmethane, diaminodiphenylsulfone, dicyandiamide, adipic dihydrazide, phenolic resins such as phenol novolac resin and cresol novolac resin, liquid polymercaptan, Polymercaptan such as polysulfide, maleic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyl nadic anhydride, pyromellitic anhydride, methylcyclohexenetetra Carboxylic anhydride, dodecyl succinic anhydride, trimellitic anhydride, chlorokronendic anhydride, benzophenone tetracarboxylic anhydride, ethylene glycol bis Acid anhydrides such as (anhydrotrimate)), curing accelerators (2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 2- Heptadecylimidazole, imidazoles such as 2-phenyl-4-methylimidazole, organic phosphines such as triphenylphosphine and tributylphosphine, benzyldimethylamine, 2-dimethylaminomethyl) phenol, 2,4,6-tris (diamino) Tertiary amines such as methyl) phenol and tetramethylhexanediamine, boron salts such as triphenylphosphine tetraphenylborate, tetraphenylphosphonium tetraphenylborate and triethylaminetetraphenylborate, 1,4-benzoyl , 1,4-naphthoquinone, 2,3-dimethyl-1,4-benzoquinone, 2,6-dimethylbenzoquinone, quinoid compounds such as 2,3-dimethoxy-1,4-benzoquinone), antistatic agents (for example, , Polyamide elastomer, quaternary ammonium salt system, pyridine derivative, aliphatic sulfonate, aromatic sulfonate, aromatic sulfonate copolymer, sulfate ester salt, polyhydric alcohol partial ester, alkyldiethanolamine, alkyldiethanolamide , Polyalkylene glycol derivatives, betaines, imidazoline derivatives, etc.), conductivity imparting agents, stress relieving agents, mold release agents (alcohols, esters of alcohols and fatty acids, alcohols and esters of dicarboxylic acids, silicone oils, etc.), Crystallization accelerators, hydrolysis inhibitors, lubricants (eg Higher fatty acids such as stearic acid, behenic acid, zinc stearate, calcium stearate, magnesium stearate, and metal salts thereof, higher fatty acid amides such as ethylene bisstearamide), impact imparting agents, slidability improvers ( Hydrocarbons such as low molecular weight polyethylene, higher alcohols, polyhydric alcohols, polyglycols, polyglycerols, higher fatty acids, higher fatty acid metal salts, fatty acid amides, esters of fatty acids and fatty alcohols, full of fatty acids and polyhydric alcohols Esters or partial esters, full or partial esters of fatty acids and polyglycols, silicones, fluororesins, etc., compatibilizers, nucleating agents, reinforcing agents, flow control agents, dyes (nitroso dyes, nitro dyes, azo dyes) , Stilbene azo dye, ketoimine dye, triphenylmethane dye , Xanthene dye, acridine dye, quinoline dye, methine / polymethine dye, thiazole dye, indamine / indophenol dye, azine dye, oxazine dye, thiazine dye, sulfur dye, aminoketone / oxyketone dye, anthraquinone dye, indigoid dye, phthalocyanine dye Dyes, etc.), sensitizers, colorants (titanium oxide, carbon black, titanium yellow, iron oxide pigments, ultramarine, cobalt blue, chromium oxide, spinel green, lead chromate pigments, cadmium pigments and other inorganic pigments Azo pigments such as azo lake pigments, benzimidazolone pigments, diarylide pigments, condensed azo pigments, phthalocyanine pigments such as phthalicyanine blue and phthalocyanine green, isoindolinone pigments, quinophthalone pigments, quinacridone pigments, Organic pigments such as condensed pigments such as condensed pigments such as len pigments, anthraquinone pigments, perinone pigments and dioxazine violet, scaly aluminum metallic pigments, spherical aluminum pigments used to improve the weld appearance, Mica powder for pearl-like metallic pigments, other metallic pigments such as those coated with inorganic polyhedral particles such as glass by metal plating or sputtering, etc.), thickener, anti-settling agent, anti-sagging agent, filler (glass fiber) , Fibrous reinforcing agents such as carbon fiber, and glass beads, calcium carbonate, talc, clay, etc.) and antifoaming agents (silicone-based antifoaming agents, surfactants, polyethers, higher alcohols, etc.) Etc.), coupling agents, light diffusing fine particles, rust preventives, antibacterial / antifungal agents, antifouling agents, conductive polymers and the like.

<Light diffusing fine particles>
Examples of the light diffusing fine particles include inorganic fine particles such as alumina, titanium oxide, calcium carbonate, barium sulfate, silicon dioxide, and glass beads, and organic fine particles such as styrene crosslinked beads, MS crosslinked beads, and siloxane crosslinked beads. Further, hollow crosslinked fine particles made of a highly transparent resin material such as methacrylic resin, polycarbonate resin, MS resin, and cyclic olefin resin, and hollow fine particles made of glass are also included. Of these, inorganic fine particles are preferable, and alumina and titanium oxide are most preferable. Further, the light diffusing fine particles may be used alone or in combination, and are not limited at all. Here, the refractive index of the fine particles is 1.7 to 3.0, preferably 1.7 to 2.5, and more preferably 1.7 to 2.0. If the refractive index is less than 1.7, the scattering property becomes too weak. On the other hand, if it exceeds 3.0, the scattering in the vicinity of the lamp becomes too strong, and as a result, uneven brightness and unevenness in emitted light color tone are likely to occur. Absent. The refractive index in the present invention is a value at a temperature of 20 ° C. based on the D line (589 nm). As a method of measuring the refractive index of the fine particles, for example, the fine particle interface is unclear by immersing the fine particles in a liquid whose refractive index can be changed little by little and observing the fine particle interface while changing the refractive index of the liquid. The method of measuring the refractive index of the liquid at the time is mentioned. An Abbe refractometer or the like can be used to measure the refractive index of the liquid. The average particle size of the light diffusing fine particles dispersed in the resin is 0.1 to 20 μm, preferably 0.2 to 15 μm, more preferably 0.3 to 10 μm, and further preferably 0.4 to 5 μm. is there. An average particle diameter of 20 μm or less is preferable because light loss due to back reflection or the like is suppressed and incident light can be efficiently diffused to the light emitting surface side. Further, it is preferable that the average particle diameter is 0.1 μm or more because the emitted light can be diffused and desired surface emission luminance and diffusibility can be obtained. The content of the light diffusing fine particles dispersed in the resin is 0.0001 to 0.03 with respect to 100 parts by weight of the acrylic resin composition from the viewpoint of the expression of the light diffusing effect and the uniformity of surface emission. Parts by weight, preferably 0.0001 to 0.01 parts by weight.

<Heat stabilizer>
Examples of the heat stabilizer include participation inhibitors such as hindered phenol antioxidants and phosphorus processing stabilizers, and hindered phenol antioxidants are preferable. Specifically, pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], thiodiethylenebis [3- (3,5-di-tert-butyl-4-hydroxy) Phenyl) propionate], octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 3,3 ′, 3 ″, 5,5 ′, 5 ″ -hexa-tert-butyl -A, a ', a''-(mesitylene-2,4,6-triyl) tri-p-cresol, 4,6-bis (octylthiomethyl) -o-cresol, 4,6-bis (dodecylthio) Methyl) -o-cresol, ethylenebis (oxyethylene) bis [3- (5-tert-butyl-4-hydroxy-m-tolyl) propionate], hexamethylenebis [3- (3,5-di-tert- Butyl-4 -Hydroxyphenyl) propionate], 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H ) -Trione, 1,3,5-tris [(4-tert-butyl-3-hydroxy-2,6-xylin) methyl] -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, 2,6-di-tert-butyl-4- (4,6-bis (octylthio) -1,3,5-triazin-2-ylamine) phenol, and the like. In particular, pentaerythritol terakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] is preferable.

  Commercially available phenolic antioxidants may be used as hindered phenolic antioxidants. Examples of such commercially available phenolic antioxidants include Irganox 1010 (Irganox 1010: pentaerythritol tetrakis [ 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], manufactured by Ciba Specialty Chemicals, Irganox 1076 (Irganox 1076: octadecyl-3- (3,5-di-t-) (Butyl-4-hydroxyphenyl) propionate, manufactured by Ciba Specialty Chemicals), Irganox 1330 (3,3 ′, 3 ″, 5,5 ′, 5 ″ -hexa-t-butyl-a) , A ′, a ″-(mesitylene-2,4,6-triyl) -P-cresol, manufactured by Ciba Specialty Chemicals), Irganox 3114: 1,3,5-tris (3,5-di-t-butyl-4-hydroxybenzyl) -1,3,5 -Triazine-2,4,6 (1H, 3H, 5H) -trione, manufactured by Ciba Specialty Chemicals), Irganox 3125 (Irganox 3125, manufactured by Ciba Specialty Chemicals), Sumizer BHT (Sumitizer BHT, Sumitomo) Chemical), Cyanox 1790 (Cyanox 1790, manufactured by Cytec), Sumilizer GA-80 (Sumilizer GA-80, manufactured by Sumitomo Chemical), Sumizer GS (Sumilizer GS, manufactured by Sumitomo Chemical), (Vitamin E (manufactured by Eisai)) It is done. Among the particularly Irganox 1010, Irganox 1076, it is preferable to use Sumilizer GS, and the like. These may be used alone, it may be used in combination of two or more.

Examples of phosphorus antioxidants include tris (2,4-di-t-butylphenyl) phosphite and bis (2,4-bis (1,1-dimethylethyl) -6-methylphenyl) ethyl. Ester phosphorous acid, tetrakis (2,4-di-t-butylphenyl) (1,1-biphenyl) -4,4′-diylbisphosphonite, bis (2,4-di-t-butylphenyl) Pentaerythritol diphosphite, bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite, bis (2,4-dicumylphenyl) pentaerythritol diphosphite, tetrakis (2,4- t-butylphenyl) (1,1-biphenyl) -4,4′-diylbisphosphonite, di-t-butyl-m-cresyl-phosphonite, etc. And the like.

  Further, a commercially available phosphorus antioxidant may be used as the phosphorus antioxidant. Examples of such commercially available phosphorus antioxidants include Irgafos 168 (Irgafos 168: Tris (2,4-dithio). -T-butylphenyl) phosphite, manufactured by Ciba Specialty Chemicals), Irgafos 12 (Irgafos 12: Tris [2-[[2,4,8,10-tetra-t-butyldibenzo [d, f] [ 1,3,2] dioxaphosphine-6-yl] oxy] ethyl] amine, manufactured by Ciba Specialty Chemicals, Irgafos 38: Bis (2,4-bis (1,1-dimethyl) Ethyl) -6-methylphenyl) ethyl ester phosphorous acid, manufactured by Ciba Specialty Chemicals), ADK STAB 329K (ADK STAB 329K, manufactured by Asahi Denka), ADK STAB PEP36 (ADK STAB PEP36, manufactured by Asahi Denka), ADK STAB PEP-8 (ADK STAB PEP-8, manufactured by Asahi Denka), Sandstab P-EPQ (manufactured by Clariant), Weston 618 (Weston 618) GE), Weston 619G (Weston 619G, manufactured by GE), Ultranox 626 (Ultranox 626, manufactured by GE), Sumilyzer GP (Sumilizer GP, manufactured by Sumitomo Chemical), and the like. These may be used alone or in combination of two or more.

  The blending amount of the heat stabilizer is not particularly limited as long as it exhibits the effect of the present application. However, if too much is added, problems such as bleeding out during processing may occur. The amount is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, still more preferably 1 part by mass or less, particularly preferably 0.8 parts by mass or less, and particularly preferably 0.01 parts by mass with respect to 100 parts by mass of the composition. It is not less than 0.8 parts by mass.

<Ultraviolet absorber>
Examples of the ultraviolet absorber include benzotriazole compounds, benzotriazine compounds, benzoate compounds, benzophenone compounds, oxybenzophenone compounds, phenol compounds, oxazole compounds, malonic ester compounds, cyanoacrylate compounds, Examples include lactone compounds, salicylic acid ester compounds, benzoxazinone compounds, and the like. In particular, benzotriazole compounds and benzotriazine compounds are preferable. These may be used alone or in combination of two or more. The ultraviolet absorber preferably has a vapor pressure (P) at 20 ° C. of 1.0 × 10 ⁻⁴ Pa or less from the viewpoint of ensuring good molding or configuration of the thermoplastic resin obtained in the present embodiment. It is more preferably 1.0 × 10 ⁻⁶ Pa or less, and further preferably 1.0 × 10 ⁻⁸ Pa or less.

  Here, good moldability means that, for example, when a film is molded, there is little adhesion of a low molecular compound to a roll. When it adheres to the roll, it reattaches to the surface, which causes the appearance to deteriorate and the optical characteristics to deteriorate.

  The melting point (Tm) of the ultraviolet absorber is preferably 80 ° C. or higher, more preferably 100 ° C. or higher, further preferably 130 ° C. or higher, and even more preferably 160 ° C. or higher. preferable.

  The ultraviolet absorber preferably has a weight reduction rate of 50% or less, more preferably 30% or less, and more preferably 15% or less when the temperature is increased from 23 ° C. to 260 ° C. at a rate of 20 ° C./min. More preferably, it is more preferably 10% or less, still more preferably 5% or less.

  The blending amount of the UV absorber may be an amount that exhibits the effect of the present application, but if it is excessively added, there is a possibility that problems such as bleeding out during processing may occur. The amount is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, still more preferably 1 part by mass or less, particularly preferably 0.8 parts by mass or less, and particularly preferably 0.01 parts by mass with respect to 100 parts by mass of the composition. It is not less than 0.8 parts by mass.

<Acrylic resin composition and other additives, kneading method with other resins>
A conventionally known method is used as a kneading method when kneading the acrylic resin (A) and rubber polymer (B) of the present embodiment or mixing with various additives or other resins. It is not particularly stipulated. In addition, other additives and other resins may be mixed at the same time when the acrylic resin (A) and the rubbery polymer (B) are kneaded, or the acrylic resin (A) and the rubbery polymer (B). After kneading in advance, other additives and other resins may be mixed.

Examples of the kneading method include kneading using an extruder, a heating roll, a kneader, a roller mixer, a Banbury mixer, and the like.
Among these, kneading with an extruder is preferable in terms of productivity.
The kneading temperature may be in accordance with the preferred processing temperature of the resin or other resin to be mixed, and is generally in the range of 140 to 300 ° C, preferably in the range of 180 to 280 ° C.

<Impact resistance of acrylic resin composition>
Since the molded body using the acrylic resin composition of the present embodiment requires impact strength, the Charpy impact strength (without notch) measured according to the ISO 179 / 1eU standard of the molded body is 23 KJ. / M ² or more is preferable.

[Molded body]
It can be set as a molded object by shape | molding the acrylic resin composition of this embodiment individually or the resin composition containing this.
As a method for producing a molded body, known methods such as injection molding, sheet molding, blow molding, injection blow molding, inflation molding, T-die molding, press molding, extrusion molding, foam molding, film molding by casting method, and the like are applied. Secondary processing molding methods such as pressure forming and vacuum forming can also be used.

  Moreover, when using the resin composition which mix | blended curable resin with the acrylic resin composition of this embodiment, the component for manufacturing a resin composition is uniformly in a solvent-free or as needed. After mixing using a solvent that can be mixed, the solvent is removed to obtain a resin composition, which is cast into a mold, cured, cooled, and then taken out of the mold to obtain a molded product. .

  It can also be cast into a mold and cured by hot pressing. The solvent for dissolving each component is not particularly limited as long as various materials can be uniformly mixed and the properties of the acrylic resin of the present embodiment are not impaired by use. Absent. For example, toluene, xylene, acetone, methyl ethyl ketone, methyl butyl ketone, diethyl ketone, cyclopentanone, cyclohexanone, dimethylformamide, methyl cellosolve, methanol, ethanol, n-propanol, iso-propanol, n-butanol, n-pentanol , N-hexanol, cyclohexanol, n-hexane, n-pentane and the like.

  Another example is a method in which a resin composition is kneaded and manufactured using a kneader such as a heating roll, kneader, Banbury mixer, extruder, etc., then cooled, pulverized, and further molded by transfer molding, injection molding, compression molding, or the like. Can be mentioned. The curing method varies depending on the curing agent used, but is not particularly limited. Examples include thermal curing, light curing, UV curing, pressure curing, moisture curing, and the like. The order of mixing the components is not particularly limited as long as the effect of the present invention can be achieved.

[Use]
The acrylic resin composition of the present embodiment can be suitably used as a material for various molded products, particularly molded products that need to be obtained by injection molding a long molded product.

  Examples of applications of the molded body include household items, OA equipment, AV equipment, battery electrical equipment, lighting equipment, vehicle use, housing use, sanitary use, ball game machine use, liquid crystal display, plasma display, and organic EL display. Retardation of light guide plate, diffuser plate, polarizing plate protective film, 1/4 wavelength plate, 1/2 wavelength plate, viewing angle control film, liquid crystal optical compensation film, etc. used in displays such as field emission display and rear projection television A film, a display front plate, a display substrate, a lens, a touch panel, and the like can be mentioned, and it can 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. It can also be used as a modifier for other resins.

  The molded body using the acrylic resin and the resin composition of the present embodiment may be subjected to surface functionalization treatment such as antireflection treatment, transparent conductive treatment, electromagnetic wave shielding treatment, and gas barrier treatment.

  The acrylic resin composition of the present embodiment has high fluidity and mechanical strength, and does not cause a jetting phenomenon at the time of molding. Therefore, the acrylic resin composition is preferably used as a molded body material having a thickness of 19 mm or less. Furthermore, it can be suitably used as a material for a thin injection molded body having a thickness of 4 mm or less.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to the following examples.

〔material〕
The raw materials used are as follows.
1) Methyl methacrylate (MMA): Asahi Kasei Chemicals (2.5 ppm of 2,4-di-6-tert-butylphenol) as a polymerization inhibitor Added)
2) Methyl acrylate (MA): manufactured by Mitsubishi Chemical (added with 14 ppm of 4-methoxyphenol manufactured by Kawaguchi Chemical Industry as a polymerization inhibitor)
3) n-octylmercaptan (NOM): manufactured by Arkema 4) 2-ethylhexyl thioglycolate: manufactured by Arkema 5) lauroyl peroxide: manufactured by Nippon Oil & Fats 6) No. 3 Calcium phosphate: manufactured by Nippon Kagaku Kogyo Co., Ltd., used as suspending agent 7) Calcium carbonate (produced by Shiraishi Kogyo Co., Ltd., used as suspending agent) 8) sodium lauryl sulfate: manufactured by Wako Pure Chemical Industries, Ltd. Use as suspension aid 9) n-Butyl acrylate (BA)
10) Styrene (St)
11) Allyl methacrylate (ALMA)
12) Polyethylene glycol diacrylate (molecular weight 200) (PEGDA)
13) Diisopropylbenzene hydroperoxide (PBP)
14) 2- (2′-Hydroxy-5′-methylphenyl) benzotriazole (HMBT)
15) Diethylene glycol diacrylate (DEGA)
(C) Thermal stabilizer; Irganox 1076 (Irganox 1076: octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate): manufactured by Ciba Specialty Chemicals)
(D) Ultraviolet absorber; Tinuvin-P (Tinvin-P: 2- (2′-hydroxy-5′-methylphenyl) benzotriazole): manufactured by Ciba Japan

〔Measuring method〕
(I. Measurement of resin composition and molecular weight)
<1. Composition analysis of acrylic resin>
The composition analysis of the acrylic 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 raised to 320 ° C. at a rate of 50 ° C./min, 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: 10 μL of 10 g chloroform solution of 0.1 g acrylic resin

A sample was collected in a platinum sample cup for a thermal decomposition apparatus, vacuum dried at 150 ° C. for 2 hours, and then the sample cup was placed in a thermal decomposition furnace, and the composition analysis of the sample was performed under the above conditions.
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, the composition ratio of the acrylic resin was determined.

  Preparation of standard sample for calibration curve: The ratio of methyl methacrylate and methyl acrylate is (methyl methacrylate / methyl acrylate) = (100 mass% / 0 mass%), (98 mass% / 2 mass%), (94 (Mass% / 6 mass%), (90 mass% / 10 mass%), (80 mass% / 20 mass%), a total of 5 kinds of solutions, 50 g of each, lauroyl peroxide 0.25 mass%, n-octyl Mercaptan (0.25% by mass) was added.

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, the acrylic resin inside was taken out, and composition analysis was performed.
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.

<2. Measurement of weight average molecular weight (Mw) and molecular weight distribution of acrylic resin>
Measuring apparatus: Nippon Analytical Industry Gel Permeation Chromatography (LC-908)
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 volume: 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 acrylic resin was measured.
Based on the area area in the GPC elution curve and the calibration curve, the weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the acrylic resin were 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 (Mw)
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) having a weight average molecular weight of 5,000 to 50,000 and the polymer (II) having a weight average molecular weight of 60,000 to 350,000 are mixed, the polymer (I) alone The GPC elution curve is measured to determine the weight average molecular weight, and the ratio of the polymer (I) present (in this specification, the charge ratio is used) is used as the GPC elution curve of the polymer (I). Multiplying and subtracting the detected intensity at the elution time from the GPC elution curve in which the polymer (I) and the polymer (II) are mixed together yields the GPC elution curve of the polymer (II) alone. From this, the weight average molecular weight of the polymer (II) was determined.

  Further, the peak molecular weight (Mp) in the GPC elution curve was determined from the GPC elution curve and the calibration curve, and the molecular weight component of 1/5 or less of the Mp was determined as follows.

  First, the area area (shaded area in FIG. 2) in the GPC elution curve of the acrylic resin is obtained. Next, the area area in the GPC elution curve is divided by the elution time corresponding to the molecular weight of 1/5 of Mp, and the area area in the GPC elution curve corresponding to the molecular weight component of 1/5 or less of Mp is obtained. From the ratio of the area to the area of the GPC elution curve, the ratio of molecular weight components equal to or less than 1/5 of Mp was determined. The measurement results are shown in Table 4 below.

<3. Measurement of composition ratio of vinyl copolymer copolymerizable with methyl methacrylate in high molecular weight component and low molecular weight component of acrylic resin>
A high molecular weight component having a cumulative area area of 0 to 2% and a low molecular weight component having a cumulative area area of 98 to 100% shown in FIG. Went. Regarding the fractionation and measurement of components, the above-mentioned <1. Analysis of composition of acrylic resin> The same apparatus and conditions as in the above were used.

  The fractionation was performed twice, and 10 μL of the fractionated sample was subjected to the above <1. Composition analysis of acrylic resin> The sample was collected in a platinum sample cup for a thermal decomposition apparatus used in pyrolysis gas chromatography analysis and mass spectrometry, and dried for 40 minutes with a vacuum dryer at 100 ° C. <1. Composition Analysis of Acrylic Resin> The composition of the acrylic resin corresponding to the accumulated area area fractionated under the same conditions as those described above was determined.

  Vinyl copolymer copolymerizable with methyl methacrylate in high molecular weight component (molecular weight component in cumulative area area 0-2%; Mh) and low molecular weight component (molecular weight component in cumulative area area 98-100%; Ml) Table 4 shows the measurement results of the composition ratio of (MA: methyl acrylate).

(II. Measurement of aggregate production)
The mixed solution containing the polymer fine particles obtained by the polymerization is passed through a 1.68 mm mesh sieve to remove the fine particle aggregates, and the obtained aggregates are dried in a drying oven at 80 ° C. for 12 hours. It was measured.
The obtained weight was divided by the total amount of the raw material (I) and the raw material (II) to calculate the aggregate generation amount (% by mass).

(III. Measurement of average particle diameter of rubbery polymer (B))
(1) Measurement of average particle diameter of rubber polymer (B) obtained in Production Example A three-layer rubber polymer emulsion was sampled, diluted with water to a solid content of 500 ppm, and UV 1200 V Absorbance at a wavelength of 550 nm was measured using a spectrophotometer (manufactured by Shimadzu Corporation). From this value, the average particle size was determined using a calibration curve prepared by measuring the absorbance in the same manner for the sample whose particle size was measured from a transmission electron micrograph.

(2) Measurement of average particle diameter of rubbery polymer (B) contained in resin composition A part of a molded piece made of an acrylic resin composition was cut out with a circular saw and then stained with RuO ₄ (ruthenic acid). A sample for observation by an ultrathin section method was prepared. Using a transmission electron microscope model manufactured by Hitachi, Ltd .: Model H-600, a cross section of the dyed rubber particles was observed and photographed. The diameter of 20 representative particles printed at a high magnification was measured on a scale to determine the average particle size of the rubber particles.

(IV. Measurement of acetone insoluble part)
After drying the acrylic resin composition pellets all day and night (about 80 ° C., about 12 hours or more), weighing about 1.0 g (W1), placing the sample in a centrifuge tube (metal tube), adding 20 ml of acetone and room temperature Then, leave it for about 1 day and shake for 2 hours on a shaker. Next, vacuum type high-speed cooling centrifuge manufactured by Hitachi Koki Co., Ltd. Model: Use CR26H, set the conditions at 5 ° C. and 24000 rpm, and centrifuge for 1 hour.

  After shaking, the supernatant is removed by decantation, and 20 ml of acetone is newly added and shaken at room temperature for 1 hour. After shaking, centrifuge for 1 hour at 5 ° C. and 24000 rpm. Again, the same method and conditions were repeated a total of 3 times. Decant the supernatant and air dry overnight.

The vacuum dryer was set to 100 ° C., taken out after vacuum drying all day and night (about 12 hours or longer), cooled to room temperature in a desiccator, and the weight of the residue was weighed (W2). The acetone insoluble part (% by weight) is calculated by the following formula (X).
Acetone insoluble part (X) = W2 / W1 × 100
(IV. Physical property measurement)

<1. Evaluation of moldability>
100 ISA dumbbell pieces were made using IS-100EN manufactured by Toshiba Machine Co., Ltd. under the conditions of a resin temperature of 250 ° C., a mold temperature of 50 ° C., and an injection speed of 50% in accordance with the ISO 527-2 standard. At that time, the evaluation of molding processability was performed with “◯” indicating that no jetting marks were observed and “×” indicating that jetting was observed.

<2. Measurement of VICAT softening temperature of acrylic resin>
In accordance with 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.

<3. Transparency>
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.

<4. Deflection temperature under load>
Measurements were performed in accordance with ISO 75-2 / A standard and used as an index for heat resistance evaluation.

<5. Tensile test>
In accordance with the ISO 527-2 standard, tensile modulus, tensile yield stress, and tensile fracture strain were measured using a 1A type dumbbell test piece.

<6. Impact resistance test of acrylic resin composition-Charpy impact strength (no notch)>
In compliance with ISO 179 / 1eU standard was measured, "×" a of less than ^{23kJ / m 2, 23kJ / m} 2 or more things as "○", was evaluated impact resistance.

<7. Evaluation of color tone>
Using a color difference meter “TC-8600A” manufactured by Nippon Denshoku Industries Co., Ltd. and using a 1A type dumbbell test piece prepared in accordance with the ISO 527-2 standard, JIS T7105 (plastic optical property test method) , YI (yellowness) in the thickness direction was measured, and the yellowness difference ΔYI was measured using the following equation.

The test piece was manufactured using Toshiba Machine IS-100EN at a molding temperature of 230 ° C and a mold temperature of 60 ° C.
ΔYI indicates the degree of yellowing of the molded product, and the smaller the value, the smaller the coloring.

Yellowness difference ΔYI = YI−YI0
ΔYI = Yellowness difference YI = Yellowness of molded product YI0 = Yellowness of air

  The obtained ΔYI value of 2.5 or less was evaluated as “◎”, the value exceeding 2.5 to 5 or less was “◯”, and the value exceeding 5 was evaluated as “x”, and evaluated in three stages.

<Example of production of acrylic resin (A)>
[Production Example 1]
2 kg of water, 65 g of tribasic calcium phosphate, 39 g of calcium carbonate, and 0.39 g of sodium lauryl sulfate were charged into a container having a stirrer to obtain a mixed solution (A).
Next, 26 kg of water was charged into a 60 L reactor and the temperature was raised to 80 ° C., and the mixture (A) and the raw material (I) for producing the polymer (I) with the blending amounts shown in Table 1 below were used. ).

Thereafter, suspension polymerization was performed while maintaining the temperature at about 80 ° C., and an exothermic peak was observed 80 minutes after the starting material of the polymer (I) was added.
Thereafter, the temperature was raised to about 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 (II) for producing the polymer (II) was added to the reactor in the blending amount shown in Table 1 below, followed by about 80 ° C. The suspension polymerization was carried out while maintaining the temperature, and an exothermic peak was observed 130 minutes after charging the raw material of the polymer (II).
Thereafter, the temperature was raised to about 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 resulting bead polymer was washed and dehydrated and dried to obtain polymer fine particles.

  Aggregates were dried in an oven at 80 ° C. for 12 hours and weighed, and the weight was divided by the total amount of raw material (I) and raw material (II), and the amount of aggregate produced (%) was measured. 0.23%.

  The obtained polymer fine particles were melt-kneaded using a φ30 mm twin screw extruder set at 240 ° C., and the strands were cooled and cut to obtain resin pellets. At that time, the extrusion workability was good.

The obtained pellets had a weight average molecular weight (Mw) of 118,000 and a molecular weight distribution (Mw / Mn) of 3.3.
Moreover, when the fluidity | liquidity of the obtained resin pellet was measured by MFR (230 degreeC / 3.8kg load), it was 1.7g / 10min.

When the tensile properties were measured, the tensile modulus was 3300 MPa, the tensile yield stress was 75 MPa, and the tensile fracture strain was 6%.
Furthermore, when Charpy impact strength (without notch) was measured as an index of impact resistance, it was 22 kJ / m ² . Moreover, when the VICAT softening temperature was measured, it was 109 degreeC and the deflection temperature under load was 100 degreeC. The total light transmittance was 92%.

[Production Examples 2 to 4]
Polymerization was performed using the raw materials shown in Table 1 in the same manner as in Example 1 to obtain polymer fine particles.
Table 2 shows the monomer charge composition of polymer (I) and polymer (II), and the ratio of polymers (I) and (II). In addition, Table 3 shows the characteristic values of the obtained polymer.

[Production Example 5]
Into 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, 26 kg of water was charged into a 60 L reactor and the temperature was raised to 80 ° C., and the mixture (A) and the raw material (I) for producing the polymer (I) with the blending amounts shown in Table 1 below were used. ).
Thereafter, suspension polymerization was performed while maintaining the temperature at about 80 ° C., and an exothermic peak was observed 65 minutes after the starting material of the polymer (I) was added.

Thereafter, after maintaining the temperature at 80 ° C. for 30 minutes, the raw material (II) for producing the polymer (II) was charged into the reactor at the blending amount shown in Table 1 below, and kept at about 80 ° C. Suspension polymerization was carried out, and an exothermic peak was observed 130 minutes after charging the raw material of the polymer (II).
Thereafter, the temperature was raised to about 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 resulting bead polymer was washed and dehydrated and dried to obtain polymer fine particles having an average particle diameter of 0.29 mm.

  Aggregates are dried in a drying oven at 80 ° C. for 12 hours, weighed, and the weight is divided by the total amount of raw material (I) and raw material (II) to measure the amount of aggregate produced (mass%). As a result, it was 0.48 mass%.

  Table 2 shows the monomer charge composition of polymer (I) and polymer (II), and the ratio of polymers (I) and (II). In addition, Table 3 shows the characteristic values of the obtained polymer.

[Production Example 6]
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 a container having a stirrer to obtain a mixed solution (A).
Next, 26 kg of water was charged into a 60 L reactor and the temperature was raised to 80 ° C., and the mixture (A), methyl methacrylate 19.5 kg, methyl acrylate 0.5 kg, lauroyl peroxide 50 g, n-octyl mercaptan 58 g Was introduced.

  Thereafter, suspension polymerization was carried out while maintaining the temperature at about 80 ° C. After observing an exothermic peak, 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.

Subsequently, 20 mass% sulfuric acid was added in order to cool to 50 degreeC and dissolve a suspension 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%.
Further, the weight average molecular weight (Mw) of the obtained polymer fine particles was 103,000. The abundance of molecular weight components equal to or less than 1/5 of Mp was 5.3%, Mh was 2.5% by mass, and Ml was 2.5% by mass.

[Production Example 7]
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 a container having a stirrer to obtain a mixed solution (A).
Next, 26 kg of water was charged into a 60 L reactor and the temperature was raised to 80 ° C., and the mixture (A), methyl methacrylate 21.2 kg, methyl acrylate 1.2 kg, lauroyl peroxide 68 g, n-octyl mercaptan 113 g Was introduced.

Thereafter, suspension polymerization was carried out while maintaining the temperature at about 80 ° C. After observing an exothermic peak, 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.
Subsequently, 20 mass% sulfuric acid was added in order to cool to 50 degreeC and dissolve a suspension 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 obtained polymer fine particles had a weight average molecular weight (Mw) of 60,000. The molecular weight component of 1/5 or less of Mp was 4.8%, Mh was 5.3%, and Ml was 5.3%.

<Production example of rubber polymer (B)>
[Production Example 8]
(B-1) Rubber-containing copolymer particles having a three-layer structure Into a reactor equipped with a reflux condenser having an internal volume of 10 L, 6868 mL of ion-exchanged water and 13.7 g of sodium dihexylsulfosuccinate were charged and rotated at 250 rpm. While stirring, the temperature was raised to 75 ° C. in a nitrogen atmosphere, so that the influence of oxygen was virtually absent (substantially oxygen-free state).

Of the mixture (1-1) consisting of MMA 907 g, BA 33 g, HMBT 0.28 g and ALMA 0.93 g, 222 g was added all at once, and after 5 minutes, 0.22 g of ammonium persulfate was added.
After 40 minutes, the remaining 719 g of (I-1) was continuously added over 20 minutes, and the addition was continued for 60 minutes.

Next, after adding 1.01 g of ammonium persulfate, a mixture (I-2) comprising 1067 g of BA, St219 g, 0.39 g of HMBT, and 27.3 g of ALMA was continuously added over 140 minutes, and the mixture was further maintained for 180 minutes. did.
Next, after adding 0.30 g of ammonium persulfate, a mixture (I-3) consisting of MMA 730 g, BA 26.5 g, HMBT 0.22 g, and NOM 0.76 g was continuously added over 40 minutes. The temperature was raised to 0 ° C. and held for 30 minutes.

The remaining latex was put into a 3% by mass sodium sulfate warm aqueous solution, salted and coagulated, then dried after repeated dehydration and washing to obtain a rubber polymer (B-1).
The rubbery polymer (B-1) obtained had an average particle size of 0.23 μm.
Moreover, the refractive index difference with the acrylic resin of manufacture examples 1-7 was 0.002.

(B-2) Production of rubbery polymer having a three-layer structure <Production Example 9>
In a 10 L beaker equipped with a stirrer and a condenser, 5.7 L of distilled water, 20 g of sodium dioctylsulfosuccinate as an emulsifier, and Rongalite l. Add 2g and dissolve uniformly. As a first layer, a homogeneous solution of 220 g of MMA, 30 g of BA, 0.8 g of ALMA, and 0.2 g of diisopropylbenzene hydroperoxide (hereinafter abbreviated as PBP) was added and polymerized at 80 ° C. The reaction was complete in about 15 minutes.

  The obtained polymer had a Tg of 108 ° C. Subsequently, as a second layer, a uniform solution of 1270 g of BA, 320 g of styrene, 20 g of diethylene glycol diacrylate (hereinafter abbreviated as DEGA), 13.0 g of ALMA, and 1.6 g of PBP was dropped at a constant temperature over 1 hour. The reaction was completed 40 minutes after the completion of the dropwise addition. The Tg of the polymer obtained by polymerizing this product alone was -38 ° C.

  Next, a uniform solution of BA 2.0 g, PBP 0.3 g, and n-octyl mercaptan (NOM) 0.1 g was added to MMA 340 g as the first layer of the first layer. The molecular weight was 1,220,000 and the Tg was 109 ° C. The reaction at this stage was complete in about 15 minutes.

Next, a solution having the same composition as that of the third layer was added to the third layer except that the amount of NOM was changed to 1.0 g. The polymer obtained by polymerizing this product alone had a molecular weight of 117,000 and a Tg of 108 ° C. This step was complete in about 15 minutes.
The temperature was then raised to 95 ° C. and held for 1 hour. The resulting emulsifier was poured into a 0.5% aqueous solution of aluminum chloride to agglomerate the polymer, washed 5 times with warm water, and dried to give a rubbery polymer. (B
-2) was obtained.

The first layer corresponds to the innermost layer, the second layer corresponds to the intermediate layer, and the third layer corresponds to the outermost layer.
The rubber polymer (B-2) obtained had an average particle size of 0.1 μm.
The refractive index difference from the acrylic resins of Production Examples 1 to 7 was 0.001.

In Table 2, (Mah) is a composition ratio of other vinyl monomer units copolymerizable with the methacrylic acid ester of the polymer (II).
In Table 2, (Mal) is the composition ratio of other vinyl monomer units copolymerizable with the methacrylic acid ester of the polymer (I).

[Examples 1-9], [Comparative Examples 1-3]
Using the 30 mmφ twin screw extruder (manufactured by Nakatani Machinery Co., Ltd .; L / D = 35) at the compounding ratio shown in Table 4, the above raw materials were set so that the resin temperature measured at the protrusion was about 250 ° C. Kneaded and evaluated by the above evaluation method. The evaluation results are shown in Table 4.

  When comparing Examples and Comparative Examples, as shown in Comparative Examples, when an acrylic resin composition composed of an acrylic resin and a rubbery polymer not having molecular weight characteristics as in the present application is used, injection molding is performed. Sometimes jetting is likely to occur, but acrylic resin compositions composed of an acrylic resin and a rubbery polymer having specific molecular weight characteristics as in the examples are excellent in molding processability because jetting does not occur. In addition, it can be seen that it has excellent fluidity and impact resistance.

  The acrylic resin composition of the present invention is used for display (apparatus) windows of mobile phones, liquid crystal monitors, liquid crystal televisions, etc., light guide plates used in liquid crystal displays, front frames of display devices, pictures, etc., and external light. Exteriors such as windows to be taken in, signboards for display, roofs of carports, sheets of display shelves, covers and gloves for lighting fixtures, molded products having secondary processing such as pressure forming, vacuum forming, blow molding, Industrial use for tail lamps, head lamps, visors, etc., parts used in ball lamps, etc., which are thin and large, yet require durability to solvents such as alcohol-based cleaning agents, waxes and wax removers. There is a possibility to use on.

1 GPC elution curve 2 Baseline

Claims (8)

It contains 80 to 99.5% by mass of methacrylic acid ester monomer units and 0.5 to 20% by mass of other vinyl monomer units copolymerizable with at least one methacrylic acid ester, and satisfies the following conditions. An acrylic resin composition characterized by comprising an acrylic resin (A) characterized by: and a rubbery polymer (B).
I) The weight average molecular weight measured by gel permeation chromatography (GPC) is 60,000 to 300,000,
II) The molecular weight component of 1/5 or less of the peak molecular weight (Mp) obtained from the GPC elution curve is 7 to 40% as the area area ratio obtained from the GPC elution curve.   The acrylic resin composition according to claim 1, comprising 1 to 200 parts by mass of a rubbery polymer (B) with respect to 100 parts by mass of the acrylic resin (A).   The acrylic resin composition according to any one of claims 1 to 2, wherein the rubber polymer (B) is an acrylic rubber polymer.   The acrylic resin composition according to any one of claims 1 to 3, wherein the rubbery polymer (B) has a multilayer structure of three or more layers.   The acrylic resin composition according to any one of claims 1 to 4, wherein the acrylic insoluble part content of the acrylic resin composition is 1 to 65 mass%.   The molded object obtained by shape | molding the acrylic resin composition as described in any one of Claims 1 thru | or 5.   The molded object obtained by injection-molding the acrylic resin composition as described in any one of Claims 1 thru | or 5.   The molded body according to any one of claims 6 to 7, which is a vehicle component.

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