JP2020029523A - Method for producing (meth)acrylic resin composition - Google Patents

Abstract

To provide a method for producing a (meth)acrylic resin composition which is excellent in continuous productivity and enables thermal degradation of a (meth)acrylic resin composition to be suppressed, and to provide a (meth)acrylic resin composition produced by the production method, and a molded body using the same.SOLUTION: The method for producing a (meth)acrylic resin composition including a (meth)acrylic resin (A) and acrylic rubber particles (B) is provided that comprises the steps of: melting and kneading the (meth)acrylic resin (A) and the acrylic rubber particles (B) in a kneading part of an extruder; and melting and filtering the melt-kneaded object with a polymer filter arranged behind the extruder, wherein a temperature (Ta) of the kneading part of the extruder and a temperature (Tb) of the polymer filter satisfy the following conditions (1), (2) and (3).<Condition>(1) -10°C≤Tb-Ta≤30°C, (2) 200°C≤Ta<280°C and (3) 200°C≤Tb<280°C.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing a (meth) acrylic resin composition. The present invention also relates to a (meth) acrylic resin composition produced by the production method and a molded article using the same.

Molded articles using (meth) acrylic resin compositions are used for applications such as optical products, decorative products, vehicle products, electric appliances, and signboards because of their excellent transparency and weather resistance. . In particular, in these applications, it is common practice to incorporate acrylic rubber particles into the (meth) acrylic resin composition.
Acrylic rubber particles used in such applications can be obtained in powder form by, for example, an emulsion polymerization method. When mixing this with other (meth) acrylic resin or additives, a single screw extruder, The mixture is melt-kneaded using a twin-screw extruder, a multi-screw extruder, or the like, extruded as strands, and cut into pellets.
On the other hand, when used for optical purposes, decorative purposes, etc., they are formed into a film or sheet. In these applications, it is desired to reduce appearance defects called fish eyes.
As a method of preventing such defects from occurring, for example, there is a method of using a filtration device called a polymer filter when melt kneading a resin and particles with a twin-screw extruder. For example, Patent Documents 1 and 2 propose a method for producing (meth) acrylic resin composition pellets containing acrylic rubber particles using a twin-screw extruder and a polymer filter as a filtration device.

JP 2013-231169 A JP 2012-149268 A

  However, in the production methods described in Patent Documents 1 and 2, venting occurs in the extruder, the torque value of the extruder is not stable, continuous productivity is reduced, and thermal deterioration of the resin composition cannot be suppressed. However, there has been a problem that the quality of the above-mentioned optical and decorative applications may not be satisfied.

  The present invention has been made in view of the above-mentioned conventional problems, and has a superior continuous productivity and a method for producing a (meth) acrylic resin composition capable of suppressing thermal deterioration of the (meth) acrylic resin composition. The task is to provide Another object of the present invention is to provide a (meth) acrylic resin composition produced by the production method, and a molded article using the same.

  In order to achieve high continuous productivity, as described above, it is important to suppress venting up in the extruder and to stabilize the torque value of the extruder at a low value. The present inventors, while examining the temperature of each part, such as the cylinder part, the polymer filter part, by simultaneously controlling both the temperature of the kneading part and the temperature of the polymer filter, particularly to maintain a specific relationship, It has been found that continuous productivity is improved and that thermal degradation of the resin composition can be suppressed, and the present invention has been completed.

That is, the present invention relates to the following [1] to [12].
[1] A method for producing a (meth) acrylic resin composition containing (meth) acrylic resin (A) and acrylic rubber particles (B),
A step of melt-kneading the (meth) acrylic resin (A) and the acrylic rubber particles (B) in a kneading section of an extruder;
Melt-filtering with a polymer filter disposed behind the extruder,
A method for producing a (meth) acrylic resin composition, wherein the temperature (Ta) of the kneading section of the extruder and the temperature (Tb) of the polymer filter satisfy the following conditions (1), (2) and (3).
<Conditions>
(1) -10 ° C ≦ Tb−Ta ≦ 30 ° C
(2) 200 ° C ≦ Ta <280 ° C
(3) 200 ° C ≦ Tb <280 ° C.
[2] The method for producing a (meth) acrylic resin composition according to [1], wherein the condition (1) is 0 ° C <Tb-Ta ≦ 30 ° C.
[3] The method for producing a (meth) acrylic resin composition according to [1] or [2], wherein the (meth) acrylic resin composition has an acid value of 5.0 μmol / g or less.
[4] The method for producing a (meth) acrylic resin composition according to any one of [1] to [3], wherein the (meth) acrylic resin (A) has a glass transition temperature of 80 ° C or higher.
[5] The composition of [1] to [4], wherein the (meth) acrylic resin composition contains 5 to 95% by mass of the (meth) acrylic resin (A) and 95 to 5% by mass of the acrylic rubber particles (B). The method for producing the (meth) acrylic resin composition according to any one of the above.
[6] The method for producing a (meth) acrylic resin composition according to any one of [1] to [5], wherein the filtration accuracy of the polymer filter is 0.5 to 30 μm.
[7] The method for producing a (meth) acrylic resin composition according to any one of [1] to [6], wherein the polymer filter is a candle type polymer filter or a leaf disk type polymer filter.
[8] The method for producing a (meth) acrylic resin composition according to [7], wherein the length of the candle-type polymer filter is 300 to 3,000 mm.
[9] The method for producing a (meth) acrylic resin composition according to any one of [1] to [8], wherein the extruder and the polymer filter are directly connected.
[10] A (meth) acrylic resin composition produced by the production method according to any one of [1] to [9].
[11] A molded article using the (meth) acrylic resin composition according to [10].
[12] The molded article according to [11], wherein the molded article is a film or a sheet.

  ADVANTAGE OF THE INVENTION According to this invention, while being excellent in continuous productivity, the manufacturing method of a (meth) acrylic resin composition which can suppress the thermal degradation of a (meth) acrylic resin composition can be provided. Further, the present invention can provide a (meth) acrylic resin composition produced by the production method and a molded article using the same.

  Hereinafter, an example of an embodiment to which the present invention is applied will be described. The numerical values specified in this specification are values obtained by the method disclosed in the embodiment or the example. Further, the numerical values “A to B” specified in the present specification indicate a range that satisfies the numerical value A and a value larger than the numerical value A and satisfies the numerical value B and a value smaller than the numerical value B. Note that other embodiments are also included in the scope of the present invention as long as they conform to the gist of the present invention. In the present specification, “(meth) acryl” means “acryl or methacryl”, and “(meth) acrylate” means “acrylate or methacrylate”.

[Method for producing (meth) acrylic resin composition]
The present invention is a method for producing a (meth) acrylic resin composition containing a (meth) acrylic resin (A) and acrylic rubber particles (B), wherein the (meth) acrylic resin (A) and the acrylic resin A step of melt-kneading the rubber particles (B) in a kneading section of the extruder; and a step of melt-filtrating the rubber particles (B) with a polymer filter disposed behind the extruder, and the temperature (Ta) of the kneading section of the extruder. And a method for producing a (meth) acrylic resin composition, wherein the temperature (Tb) of the polymer filter satisfies the following conditions (1), (2) and (3).
<Conditions>
(1) -10 ° C ≦ Tb−Ta ≦ 30 ° C
(2) 200 ° C ≦ Ta <280 ° C
(3) 200 ° C ≦ Tb <280 ° C.

  In the present invention, since the temperature (Ta) of the kneading section of the extruder and the temperature (Tb) of the polymer filter are each within a predetermined range and the relationship between the two temperatures is defined, venting up in the extruder is suppressed. In addition, the torque value of the extruder can be stabilized at a low value, and as a result, continuous productivity can be improved and thermal deterioration of the resin composition can be suppressed. Hereinafter, the present invention will be described in detail.

<(Meth) acrylic resin (A)>
The (meth) acrylic resin (A) used in the present invention is not particularly limited as long as it has a structural unit derived from a (meth) acrylic acid ester. From the viewpoint of improving heat resistance, for example, methacrylic resin is used. Those mainly composed of structural units derived from methyl acid are preferred. When the (meth) acrylic resin (A) is mainly composed of a structural unit derived from methyl methacrylate, its content is preferably 50% by mass or more, and more preferably 80% by mass or more, from the viewpoint of improving heat resistance. Is more preferably 90% by mass or more, even more preferably 95% by mass or more, and particularly preferably 98% by mass or more, and all the structural units are methyl methacrylate units. It may be.

The (meth) acrylic resin (A) may contain a structural unit derived from a monomer other than methyl methacrylate. Such other monomers are not particularly limited as long as they can be copolymerized with methyl methacrylate. For example, methyl acrylate, ethyl acrylate, n-propyl acrylate, iso-propyl acrylate, n-acrylate -Butyl, iso-butyl acrylate, sec-butyl acrylate, tert-butyl acrylate, amyl acrylate, isoamyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, pentadecyl acrylate, acrylic acid Dodecyl, phenyl acrylate, benzyl acrylate, phenoxyethyl acrylate, 2-hydroxyethyl acrylate, 2-ethoxyethyl acrylate, glycidyl acrylate, allyl acrylate, cyclohexyl acrylate, norbornyl acrylate, isobornyl acrylate A Ester acrylate; ethyl methacrylate, n-propyl methacrylate, iso-propyl methacrylate, n-butyl methacrylate, iso-butyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, amyl methacrylate, methacrylic acid Isoamyl, n-hexyl methacrylate, 2-ethylhexyl methacrylate, pentadecyl methacrylate, dodecyl methacrylate, phenyl methacrylate, benzyl methacrylate, phenoxyethyl methacrylate, 2-hydroxyethyl methacrylate, 2-ethoxy methacrylate Methacrylates other than methyl methacrylate such as ethyl, glycidyl methacrylate, allyl methacrylate, cyclohexyl methacrylate, norbornyl methacrylate, and isobornyl methacrylate; Unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic anhydride, maleic acid, and itaconic acid or anhydrides thereof; olefins such as ethylene, propylene, 1-butene, isobutylene and 1-octene; butadiene, isoprene, myrcene, etc. Conjugated diene; aromatic vinyl compounds such as styrene, α-methylstyrene, p-methylstyrene and m-methylstyrene; acrylamide, methacrylamide, acrylonitrile, methacrylonitrile, vinyl acetate, vinylpyridine, vinyl ketone, vinyl chloride, chloride Vinylidene, vinylidene fluoride and the like.
Among them, acrylates are preferable, and methyl acrylate, ethyl acrylate, n-propyl acrylate, iso-propyl acrylate, n-butyl acrylate, iso-butyl acrylate, and sec-butyl acrylate are more preferable. preferable.
As the (meth) acrylic resin (A) used in the present invention, one type may be used alone, or two or more types may be used in combination.

  The (meth) acrylic resin (A) used in the present invention contains a structural unit derived from methyl methacrylate and a structural unit derived from a compound having a ring structure in the molecule such as maleic anhydride. It may be united. By containing a structural unit derived from a compound having a ring structure in the molecule, the heat resistance of the (meth) acrylic resin (A) and a molded article obtained therefrom is improved. When the (meth) acrylic resin (A) contains a structural unit derived from a compound having a ring structure in the molecule, the total content is preferably 1 to 40% by mass, more preferably 1 to 20% by mass. , More preferably 1 to 5% by mass.

  As a structural unit derived from a compound having a ring structure in the molecule, a structural unit derived from a compound containing a> CH—O—C (＝ O) — group in the ring structure, —C (＝ O) —O—C A structural unit derived from a compound containing a (＝ O)-group in a ring structure, a structural unit derived from a compound containing a -C (＝ O) —NC (＝ O) — group in a ring structure, and> CH— Structural units derived from compounds containing an O-CH <group in the ring structure are preferred. Structural units derived from compounds having a ring structure in the molecule include a cyclic monomer having a polymerizable unsaturated carbon-carbon double bond such as maleic anhydride, N-substituted maleimide, etc., together with methyl methacrylate or the like. The (meth) acrylic resin (A) can be contained in the (meth) acrylic resin (A) by polymerizing or by subjecting a part of the molecular chain of the (meth) acrylic resin (A) obtained by the polymerization to intramolecular condensation cyclization.

  When the (meth) acrylic resin (A) contains a structural unit derived from a monomer other than methyl methacrylate, the content is preferably 50% by mass or less, more preferably 20% by mass or less, and more preferably 10% by mass or less. It is more preferably at most 5 mass%, more preferably at most 5 mass%, particularly preferably at most 2 mass%.

  The lower limit of the glass transition temperature (Tg) of the (meth) acrylic resin (A) is preferably 80 ° C, more preferably 100 ° C, from the viewpoint of the balance between heat resistance and moldability, and more preferably 105 ° C. It is more preferable that the temperature is ° C. Further, the upper limit is preferably 140 ° C., more preferably 135 ° C., further preferably 130 ° C., and particularly preferably 125 ° C. The glass transition temperature can be adjusted by changing the type and amount of the monomer copolymerized with methyl methacrylate, changing the stereoregularity by changing the polymerization temperature, and the like.

  The glass transition temperature can be measured according to JIS K7121: 2012. That is, the temperature of the (meth) acrylic resin (A) is once raised to 200 ° C., then cooled to room temperature, and then the temperature is raised from room temperature to 200 ° C. at a rate of 10 ° C./min by differential scanning calorimetry. The DSC curve is measured, and the midpoint glass transition temperature determined from the DSC curve measured at the time of the second heating can be used as the glass transition temperature of the (meth) acrylic resin (A).

  The stereoregularity of the (meth) acrylic resin (A) is not particularly limited, and for example, a (meth) acrylic resin (A) having stereoregularity such as isotactic, heterotactic, and syndiotactic can be used.

The weight average molecular weight of the (meth) acrylic resin (A) is preferably from 60,000 to 150,000. If the weight average molecular weight is at least the lower limit, mechanical properties will be high, and if it is at most the lower limit, the melt viscosity will be low and workability will be improved. In light of the above, the weight average molecular weight is more preferably from 85,000 to 120,000, and still more preferably from 90,000 to 100,000.
The weight average molecular weight of the (meth) acrylic resin (A) can be measured by the method described in Examples.

  The method for producing the (meth) acrylic resin (A) is not particularly limited, and can be obtained, for example, by polymerizing a monomer mainly composed of methyl methacrylate. In addition, the weight average molecular weight of the (meth) acrylic resin (A) can be adjusted by the amounts of the polymerization initiator and the chain transfer agent.

  The polymerization initiator used for producing the (meth) acrylic resin (A) is not particularly limited as long as it generates a reactive radical. For example, tert-hexylperoxyisopropyl monocarbonate, tert-hexylperoxy-2-carbonate Ethylhexanoate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, tert-butylperoxypivalate, tert-hexylperoxypivalate, tert-butylperoxyneodecano Ethate, tert-hexylperoxy neodecanoate, 1,1,3,3-tetramethylbutylperoxy neodecanoate, 1,1-bis (tert-hexylperoxy) cyclohexane, benzoyl peroxide, 3, 5,5-trimethylhexanoyl peroxide, lauro Peroxide, 2,2'-azobis (2-methylpropionitrile), 2,2'-azobis (2-methylbutyronitrile), dimethyl 2,2'-azobis (2-methylpropionate) and the like. No. Among these, 2,2'-azobis (2-methylpropionitrile), 2,2'-azobis (2-methylbutyronitrile), dimethyl 2,2'-azobis (2-methylpropionate) and the like Is preferred.

  Examples of the chain transfer agent used for producing the (meth) acrylic resin (A) include n-octyl mercaptan, n-dodecyl mercaptan, tert-dodecyl mercaptan, 1,4-butanedithiol, 1,6-hexanedithiol, and ethylene glycol. Bisthiopropionate, butanediol bisthioglycolate, butanediol bisthiopropionate, hexanediol bisthioglycolate, hexanediol bisthiopropionate, trimethylolpropane tris- (β-thiopropionate), And alkyl mercaptans such as pentaerythritol tetrakisthiopropionate. Of these, monofunctional alkyl mercaptans such as n-octyl mercaptan and n-dodecyl mercaptan are preferred.

  As the (meth) acrylic resin (A), commercially available products may be used. For example, “Parapet H1000B” [MFR: 22 g / 10 min (230 ° C., 37.3 N)], “Parapet GF” [MFR: 15 g / 10 min (230 ° C., 37.3 N)], “Parapet EH” [MFR: 1.3 g / 10 min (230 ° C., 37.3 N)], “Parapet HRL” [MFR: 2.0 g / 10 min (230 C, 37.3 N)], "Parapet HRS" [MFR: 2.4 g / 10 min (230 C, 37.3 N)] and "Parapet G" [MFR: 8.0 g / 10 min (230 C, 37.N). 3N)] [all are trade names, manufactured by Kuraray Co., Ltd.].

<Acrylic rubber particles (B)>
The acrylic rubber particles (B) used in the present invention enhance the dispersibility of the acrylic rubber particles (B) in the molded body of the (meth) acrylic resin composition, and have high transparency and high mechanical properties. In view of the above, it is preferable to have a multilayer structure having at least an elastic layer and an outer layer covering the elastic layer. Further, from the viewpoint of improving the impact resistance while keeping the hardness of the molded body high, it is more preferable to have a multilayer structure having an inner layer, an elastic layer covering the inner layer, and an outer layer covering the elastic layer. preferable.
Hereinafter, preferred embodiments of the acrylic rubber particles (B) in the present invention will be described in the order of the elastic layer, the inner layer, and the outer layer.

(Elastic layer)
The elastic layer of the acrylic rubber particles (B) used in the present invention is at least one selected from the group consisting of alkyl acrylate units having an alkyl group having 1 to 8 carbon atoms and conjugated diene monomer units. It is preferable to include a crosslinked rubber polymer component (I) having 50% by mass or more of the monomer unit (I-1) (hereinafter, simply referred to as “monomer unit (I-1)”).
Examples of the crosslinked rubber polymer component (I) include a homopolymer of an alkyl acrylate, a copolymer having an alkyl acrylate unit of 50% by mass or more, and a monomer unit other than the alkyl acrylate of 50% by mass or less. Examples include a polymer, a homopolymer of a conjugated diene-based monomer, and a copolymer having 50% by mass or more of a conjugated diene-based monomer unit.

Examples of the copolymer having a conjugated diene-based monomer unit of 50% by mass or more include rubber particles described in JP-A-10-182755 and acrylic graft copolymers described in JP-A-62-151415. And the like. Among them, from the viewpoint of transparency, a copolymer having 50% by mass or more of alkyl acrylate units and 50% by mass or less of monomer units other than alkyl acrylate units is preferable.
The content of the monomer unit (I-1) in the crosslinked rubber polymer component (I) is preferably from 60 to 99% by mass, more preferably from 70 to 95% by mass, and still more preferably from the viewpoint of adhesion. 80 to 90% by mass.

  As the alkyl acrylate, those having 1 to 8 carbon atoms in the alkyl group are used, and those having 4 to 8 carbon atoms are preferable. Specifically, for example, methyl acrylate, ethyl acrylate, n-propyl acrylate, iso-propyl acrylate, n-butyl acrylate, iso-butyl acrylate, tert-butyl acrylate, 2-ethylhexyl acrylate, and the like Is mentioned. Among these, n-butyl acrylate and 2-ethylhexyl acrylate are preferred, and n-butyl acrylate is more preferred.

The crosslinked rubber polymer component (I) has a crosslinked structure. Such a crosslinked structure may be formed by irradiation with an electron beam, or may be formed by using a polyfunctional monomer as a monomer of the crosslinked rubber polymer component (I). It is preferable to use
Such polyfunctional monomers include alkenyl esters of unsaturated carboxylic acids such as allyl (meth) acrylate and methallyl (meth) acrylate; dialkenyl esters of dibasic acids such as diallyl maleate; alkylene glycol di (meth) ) Unsaturated carboxylic acid diesters of glycols such as acrylate. Of these, alkenyl esters of unsaturated carboxylic acids are preferred, allyl (meth) acrylate is more preferred, and allyl methacrylate is even more preferred.
The content of the polyfunctional monomer unit in the crosslinked rubber polymer component (I) is a balance between the viewpoint of improving the mechanical strength of the acrylic rubber particles by crosslinking and improving the impact resistance of the resin composition and the fluidity. Therefore, it is preferably 0.01 to 5% by mass, more preferably 0.05 to 4% by mass, and still more preferably 0.1 to 3% by mass.

Further, the crosslinked rubber polymer component (I) preferably contains a unit derived from a monomer other than the alkyl acrylate and the polyfunctional monomer. Examples of such a monomer include alkyl methacrylates such as methyl methacrylate and ethyl methacrylate; (meth) acrylates containing an aromatic group such as benzyl (meth) acrylate and phenyl (meth) acrylate; styrene, alkyl Styrene-based monomers such as styrene; and unsaturated nitriles such as acrylonitrile and methacrylonitrile.
Among these, a unit derived from an aromatic compound is preferable from the viewpoint of adjusting the refractive index, a styrene-based monomer or an aromatic group-containing (meth) acrylate is preferable, and a styrene-based monomer is more preferable. Is more preferred.
The content of the unit derived from the aromatic compound in the crosslinked rubber polymer component (I) is preferably 1 to 40% by mass, more preferably 5 to 30% by mass, and still more preferably 10 to 30% by mass from the viewpoint of the refractive index. 20% by mass.

  The elastic layer may contain a plurality of crosslinked rubber polymer components having different compositions as the crosslinked rubber polymer component (I), and the elastic layer contains components other than the crosslinked rubber polymer component (I). May be contained. However, the content of the crosslinked rubber polymer component (I) in the elastic layer is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 100% by mass.

(Inner layer)
The acrylic rubber particles (B) used in the present invention may have an inner layer inside the elastic layer from the viewpoint of improving the mechanical properties of the molded article, that is, improving the impact resistance while maintaining high hardness. Preferably, the inner layer contains a polymer component (i) having 50% by mass or more of methacrylic acid alkyl ester units. The polymer component (i) may have a covalent bond with the crosslinked rubber polymer component (I). The content of the alkyl methacrylate unit in the polymer component (i) is preferably 60 to 99% by mass, more preferably 70 to 99% by mass, still more preferably 80 to 99% by mass, and particularly preferably 85 to 98% by mass. %, Most preferably 90-97% by weight.
Examples of the alkyl methacrylate include methyl methacrylate and ethyl methacrylate. Of these, methyl methacrylate is preferred.

  The polymer component (i) preferably has a crosslinked structure in the molecule from the viewpoint of improving the mechanical strength of the acrylic rubber particles. Such a crosslinked structure is preferably formed by using a polyfunctional monomer as a monomer of the polymer component (i). Examples of such a polyfunctional monomer include those similar to the crosslinked rubber polymer component (I) described above. Among them, alkenyl esters of unsaturated carboxylic acids are preferred, allyl (meth) acrylate is more preferred, and allyl methacrylate is still more preferred. The polyfunctional monomer unit in the polymer component (i) is preferably 0.1 to 5% by mass, more preferably 0.15 to 1% by mass, and still more preferably 0.18 to 0% by mass from the viewpoint of mechanical properties. 0.5% by mass.

  The polymer component (i) may have a unit derived from a monomer other than the alkyl methacrylate and the polyfunctional monomer. Examples of such a monomer include alkyl acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate and 2-ethylhexyl acrylate; styrene monomers such as styrene and alkylstyrene; And unsaturated nitriles such as acrylonitrile and methacrylonitrile. Among these, from the viewpoint of adhesion, alkyl acrylate is preferred, and methyl acrylate is more preferred.

The content of units derived from monomers other than the alkyl methacrylate in the polymer component (i) is preferably 40% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less, particularly preferably Preferably it is 15% by mass or less, most preferably 10% by mass or less.
The inner layer may contain a plurality of polymer components having different compositions as the polymer component (i), and may contain components other than the polymer component (i). However, the content of the polymer component (i) in the inner layer is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 100% by mass.

The mass ratio of the polymer component (i) to the crosslinked rubber polymer component (I) [polymer component (i) / crosslinked rubber polymer component (I)] is preferably 5/95 to 90/10, more preferably The ratio is 10/90 to 70/30, more preferably 20/80 to 60/40, even more preferably 30/70 to 50/50.
The mass ratio is calculated from the mass ratio of the monomer mixture of these polymer components.

(Outer layer)
The outer layer constituting the acrylic rubber particles preferably has a methyl methacrylate unit of 75% by mass or more and contains a hard polymer component (II) graft-bonded to a crosslinked rubber polymer component (I).
The hard polymer component (II) preferably has 75 to 99% by mass of methyl methacrylate units and 1 to 25% by mass of acrylate units from the viewpoint of mechanical properties of the molded product, and preferably has 80 to 97% of methyl methacrylate units. It is more preferable to have 3% to 20% by mass of an acrylate unit and more preferably 90% to 96% by mass of a methyl methacrylate unit and 4% to 10% by mass of an acrylate unit.

  Examples of the ester group of the acrylate used in the hard polymer component (II) include an alkyl group, a cycloalkyl group, a phenyl group, and derivatives thereof having 1 to 12 carbon atoms. Specific acrylates include, for example, methyl acrylate, ethyl acrylate, n-propyl acrylate, iso-propyl acrylate, n-butyl acrylate, iso-butyl acrylate, tert-butyl acrylate, acrylic acid Examples include 2-ethylhexyl, n-octyl acrylate, n-lauryl acrylate, 2-hydroxyethylhexyl acrylate, cyclohexyl acrylate, isobornyl acrylate, tetrahydrofuryl acrylate, benzyl acrylate, and phenyl acrylate. Among these, methyl acrylate, n-butyl acrylate, cyclohexyl acrylate, and benzyl acrylate are preferred from the viewpoint of the balance between the active energy ray-curable hard coat and the adhesive with the adhesive, heat resistance, and handleability. preferable.

  The outer layer may contain a plurality of hard polymer components having different compositions as the hard polymer component (II), and may contain components other than the hard polymer component (II). However, the content of the hard polymer component (II) in the outer layer is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 100% by mass.

(Graft rate)
In the acrylic rubber particles according to the present invention, the hard polymer component (II) is preferably graft-bonded to the crosslinked rubber polymer component (I). The graft ratio of the acrylic rubber particles is preferably 11 to 33% by mass, more preferably 15 to 30% by mass, and still more preferably 20 to 30% by mass.
The graft ratio is defined by the mass ratio of the graft-bonded hard polymer component (II) to the crosslinked rubber polymer component (I), and when the graft ratio is 11% by mass or more, the heat resistance is improved. When the content is not more than mass%, the adhesion to the active energy ray-curable resin is improved.
The graft ratio is determined by immersing the acrylic rubber particles in acetone, centrifuging the particles with a centrifugal separator, removing the acetone-soluble matter, and drying the acetone-soluble matter. ).
Graft ratio = {[mass of acetone-insoluble component−mass of crosslinked rubber polymer component (I)] / mass of crosslinked rubber polymer component (I)} × 100 (a)
Here, the mass of the crosslinked rubber polymer component (I) is the total mass of the monomers of the crosslinked rubber polymer component (I) in the polymerization. In the case where the acrylic rubber particles further have the inner layer inside the elastic layer, the mass of the crosslinked rubber polymer component (I) in the above formula (a) is the mass of the crosslinked rubber polymer component (I) and the polymer component. It is the sum of the masses of the monomers of (i).

  The proportion of the hard polymer component (II) in the acrylic rubber particles is preferably 5 to 50% by mass, more preferably 10 to 30% by mass, further preferably 10 to 25% by mass, and particularly preferably 15 to 25% by mass. 22% by mass. By setting the proportion of the hard polymer component (II) in the acrylic rubber particles in the above range, even when the hard polymer component (II) is graft-bonded to the crosslinked rubber polymer component (I) by 100% by mass, the acrylic polymer component (II) is grafted. The graft ratio of the rubber particles can be set within the above range, and the degree of freedom of the blending amount of the graft-binding polyfunctional monomer increases. In addition, the degree of swelling of the acrylic rubber particles due to impregnation with the active energy ray-curable resin can be controlled with higher precision, and it is easy to achieve both adhesion and suppression of whitening.

The apparent number average molecular weight of the hard polymer component (II) is preferably from 10,000 to 100,000, more preferably from 15,000 to 60,000, and still more preferably from 30,000 to 50,000. It is. When the apparent number average molecular weight is 10,000 or more, heat resistance is improved, and when it is 100,000 or less, adhesion is improved.
Incidentally, the apparent number average molecular weight of the hard polymer component (II) is based on the fact that the monomer mixture used for producing the hard polymer component (II) of the acrylic rubber particles is the same as the crosslinked rubber polymer component (I). The same conditions as those for producing the hard polymer component (II) of the acrylic rubber particles under the condition that the inner layer is not included, and when the crosslinked rubber polymer component (I) and the polymer component (i) are not present when the inner layer is provided. And the number average molecular weight of the polymer obtained by polymerization. Such apparent number average molecular weight can be adjusted by the amount of a chain transfer agent such as thiol.

In the acrylic rubber particles, a more preferred form of the crosslinked rubber polymer component (I) preferably has a glass transition temperature of 0 ° C. or lower, and the crosslinked rubber polymer component (I) measured independently at 23 ° C. ) And the refractive index (nP23) of the hard polymer component (II) satisfy the relationship of the following formula (b), and the crosslinked rubber polymer component (I) when measured at 70 ° C. Temperature change ((nR23-nR70) / (70-23)) of the refractive index of the crosslinked rubber polymer component (I) determined from the refractive index (nR70) and nR23, and the refraction of the hard polymer component (II) It is possible that the temperature change amount ((nP23−nP70) / (70−23)) of the refractive index of the hard polymer component (II) obtained from the refractive index (nP70) and nP23 satisfies the relationship of the following formula (c). preferable.
| NR23-nP23 | <0.01 (b)
| [(NR23-nR70) / (70-23)]-[(nP23-nP70) / (70-23)] | <0.00025 (c)
By satisfying the above relationship, a difference in refractive index between the crosslinked rubber polymer component (I) and the hard polymer component (II) due to temperature can be suppressed, and as a result, haze is reduced over a wide temperature range, and transparency is improved. improves.

  From the viewpoint of impact resistance, the average particle size of the acrylic rubber particles is preferably 0.03 to 0.50 μm, more preferably 0.07 to 0.40 μm, and 0.15 to 0.30 μm. It is even more preferred.

(Polymerization initiator)
The polymerization initiator used for producing the acrylic rubber particles is not particularly limited as long as it generates a reactive radical. For example, a water-soluble inorganic initiator such as potassium persulfate and ammonium persulfate; A redox initiator obtained by using a sulfite or a thiosulfate in combination with an organic peroxide; a redox initiator obtained by using a ferrous salt or sodium sulfoxylate in combination with an organic peroxide.

(Chain transfer agent)
Examples of the chain transfer agent used for producing the acrylic rubber particles include, for example, n-octyl mercaptan, n-dodecyl mercaptan, tert-dodecyl mercaptan, 1,4-butanedithiol, 1,6-hexanedithiol, and ethylene glycol bisthiopropio. , Butanediol bisthioglycolate, butanediol bisthiopropionate, hexanediol bisthioglycolate, hexanediol bisthiopropionate, trimethylolpropane tris- (β-thiopropionate), pentaerythritol tetrakisthio And alkyl mercaptans such as propionate. Of these, monofunctional alkyl mercaptans such as n-octyl mercaptan and n-dodecyl mercaptan are preferred.

<Composition of (meth) acrylic resin composition>
The (meth) acrylic resin composition of the present invention contains (meth) acrylic resin (A) and acrylic rubber particles (B), and (meth) acrylic resin (A) with respect to acrylic rubber particles (B) The ratio [(A) / (B)] is preferably 5/95 to 95/5 from the viewpoints of moldability, mechanical properties of the molded body, and heat resistance, and is 30/70 to 90/10. Is more preferably 50/50 to 85/15, particularly preferably 60/40 to 84/16, and most preferably 77/23 to 83/17.

  From the viewpoint of moldability and mechanical properties of the molded body, the contents of the (meth) acrylic resin (A) and the acrylic rubber particles (B) in the (meth) acrylic resin composition are within the following ranges, respectively. Is preferred. That is, the content of the (meth) acrylic resin (A) is preferably from 5 to 95% by mass, more preferably from 30 to 90% by mass, even more preferably from 60 to 90% by mass, and the acrylic rubber particles The content of (B) is preferably from 95 to 5% by mass, more preferably from 70 to 10% by mass, even more preferably from 40 to 10% by mass.

  The acid value of the (meth) acrylic resin composition obtained by the present invention indicates the degree of thermal deterioration of the resin composition, and from the viewpoint of suppressing a decrease in the appearance of a molded article produced from the resin composition. 5.0 μmol / g or less, preferably 4.9 μmol / g or less, more preferably 4.8 μmol / g or less. The acid value in the present invention can be measured according to the method described in Examples.

<Additives>
The (meth) acrylic resin composition may contain various additives as needed as long as the effects of the present invention are not impaired. The type of additive is not particularly limited, and examples thereof include an ultraviolet absorber, a polymer processing aid, a light stabilizer, an antioxidant, a heat stabilizer, a lubricant, an antistatic agent, a pigment, a dye, a matting agent, and a filler. , An impact-resistant auxiliary, and a plasticizer. One type of additive may be used alone, or two or more types may be used in combination at any ratio. The additive may be an organic compound or an inorganic compound, but is preferably an organic compound from the viewpoint of dispersibility in the resin composition.

(UV absorber)
The (meth) acrylic resin composition obtained by the present invention preferably contains an ultraviolet absorber as the additive described above. An ultraviolet absorber is a compound having the ability to absorb ultraviolet light, and has a function of mainly converting light energy to heat energy. Examples of organic ultraviolet absorbers include benzophenone-based, salicylate-based, benzotriazole-based, triazine-based, benzoate-based, cyanoacrylate-based, oxalic anilide-based, malonate-based, and formamidine-based ultraviolet absorbers. Can be

Examples of the benphenone-based ultraviolet absorber include, for example, 2,4-dihydroxybenzophenone, 4-n-octyloxy-2-hydroxybenzophenone, 2,2′-dihydroxy-4,4′-dimethoxybenzophenone, 2-hydroxy-4- n-octyloxybenzophenone, bis (5-benzoyl-4-hydroxy-2-methoxyphenyl) methane, 1,4-bis (4-benzoyl-3-hydroxyphenone) -butane and the like.
Examples of the salicylate-based ultraviolet absorber include p-tert-butylphenyl salicylate. Examples of the benzoate-based ultraviolet absorber include 2,4-di-tert-butylphenyl-3 ′, 5′-di-tert-butyl-4′-hydroxybenzoate and the like.

  Examples of the benzotriazole-based ultraviolet absorber include 2,2′-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol], -(3,5-di-tert-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (2H-benzotriazol-2-yl) -p-cresol, 2- (2H-benzotriazole-2 -Yl) -4,6-bis (1-methyl-1-phenylethyl) phenol, 2-benzotriazol-2-yl-4,6-di-tert-butylphenol, 2- [5-chloro (2H)- Benzotriazol-2-yl] -4-methyl-6- (tert-butyl) phenol, 2- (2H-benzotriazol-2-yl) -4,6-di-t rt-butylphenol, 2- (2H-benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol, 2- (2H-benzotriazol-2-yl) -4-methyl -6- (3,4,5,6-tetrahydrophthalimidylmethyl) phenol, methyl 3- [3- (2H-benzotriazol-2-yl) -5-tert-butyl-4-hydroxyphenyl] propionate / Reaction product of polyethylene glycol 300, 2- (2H-benzotriazol-2-yl) -6-dodecyl-4-methylphenol, 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- [2- Hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 3- (2H-benzo Riazor 2-yl) -5- (1,1-dimethylethyl) -4-hydroxy -C7-9 alkyl esters.

Examples of the triazine-based ultraviolet absorber include 2,4-diphenyl-6- (2-hydroxy-4-methoxyphenyl) -1,3,5-triazine and 2,4-diphenyl-6- (2-hydroxy- 4-ethoxyphenyl) -1,3,5-triazine, 2,4-diphenyl- (2-hydroxy-4-propoxyphenyl) -1,3,5-triazine, 2,4-diphenyl- (2-hydroxy- 4-butoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-butoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- ( 2-hydroxy-4-hexyloxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-octyloxyphenyl) -1,3,5- Liazine, 2,4-diphenyl-6- (2-hydroxy-4-dodecyloxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-benzyloxyphenyl)- 1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-butoxyethoxy) -1,3,5-triazine, 2,4-bis (2-hydroxy-4-butoxyphenyl) -6- (2,4-dibutoxyphenyl) -1,3-5-triazine, 2,4-bis (2,4-dimethylphenyl) -6- [2-hydroxy-4- (3-octyloxy- 2-hydroxypropyloxy) -5-α-cumylphenyl] -s-triazine skeleton.
One kind of the ultraviolet absorber may be used alone, or two or more kinds may be used in combination at an arbitrary ratio. The UV absorber used in the present invention is particularly preferably a benzotriazole-based UV absorber from the viewpoint of compatibility and weather resistance. Among them, 2,2′-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol] is preferable.

  When the (meth) acrylic resin composition contains an ultraviolet absorber, the content is 0.5 to 0.5 parts by mass based on a total of 100 parts by mass of the (meth) acrylic resin (A) and the acrylic rubber particles (B). It is preferably 20 parts by mass, more preferably 1.0 to 10 parts by mass, and still more preferably 1.5 to 5 parts by mass. When the content of the ultraviolet absorber is within the above range, a molded product using the (meth) acrylic resin composition can be given sufficient ultraviolet absorption performance.

(Polymer processing aid)
As the polymer processing aid, it is usually preferable to use polymer particles which can be produced by an emulsion polymerization method and have a particle diameter of 0.05 to 0.5 μm. The polymer particles may be single-layer particles composed of a polymer having a single composition ratio and a single intrinsic viscosity, or multilayer particles composed of two or more polymers having different composition ratios or intrinsic viscosities. You may. Among these, particles having a two-layer structure having a polymer layer having a low intrinsic viscosity in the inner layer and a polymer layer having a high intrinsic viscosity of 5 dL / g or more in the outer layer are preferable.

The polymer processing aid used in the present invention preferably has an intrinsic viscosity of 3 to 6 dL / g. When the intrinsic viscosity is within the above range, the moldability of the resin composition is improved.
Commercially available polymer processing aids include, for example, Paraloid K125, K125P (all trade names, manufactured by Dow Chemical Japan Co., Ltd.), Metablen P-530A, P-550A (all trade names, manufactured by Mitsubishi Chemical Corporation) ), Kaneace PA-20, PA-30 (all are trade names, manufactured by Kaneka Corporation).

  When the (meth) acrylic resin composition contains a polymer processing aid, the content is 0.1% by mass based on a total of 100 parts by mass of the (meth) acrylic resin (A) and the acrylic rubber particles (B). The amount is preferably 1 to 15 parts by mass, more preferably 0.5 to 10 parts by mass, and still more preferably 1.0 to 5 parts by mass. When the content of the polymer processing aid is within the above range, moldability is improved.

〔Antioxidant〕
The antioxidant used in the present invention is not particularly limited, and includes, for example, a hindered phenol-based antioxidant and a phosphorus-based antioxidant, and a hindered phenol-based antioxidant is particularly preferable.

  The hindered phenolic antioxidant is not particularly limited, but specifically, pentaerythritol-tetrakis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate), thiodiethylene-bis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate), octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, N, N′-hexane -1,6-diylbis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionamide), diethyl ((3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl) Methyl) phosphate, 3,3 ′, 3 ″, 5,5 ′, 5 ″ -hexa-tert-butyl-a, a ′, a '-(Mesitylene-2,4,6-triyl) tri-p-cresol, ethylenebis (oxyethylene) bis (3- (5-tert-butyl-4-hydroxy-m-tolyl) propionate), hexamethylene- Bis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate), 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) -1,3 , 5-Triazine-2,4,6 (1H, 3H, 5H) -trione, 1,3,5-tris ((4-tert-butyl-3-hydroxy-2,6-xylyl) 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-triazine -2-b Amino) phenol, 3,9-bis (2- (3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy) -1,1-dimethylethyl) -2,4,8,10 -Tetraoxaspiro (5,5) undecane and the like. These may be used alone or in combination of two or more.

  Further, a commercially available phenolic antioxidant may be used as the hindered phenolic antioxidant, and such a commercially available phenolic antioxidant is not particularly limited, and specifically, Irganox 1010 , Irganox 1076, Irganox 1330, Irganox 3114, Irganox 3125 (all trade names, manufactured by BASF Japan KK), Sumilizer BHT, Sumilizer GA-80, Sumilizer GS (all trade names, manufactured by Sumitomo Chemical Co., Ltd.) ), Cyanox 1790 (trade name, manufactured by Cytec), vitamin E (manufactured by Eisai Co., Ltd.), and the like. Among these, it is particularly preferable to use Irganox 1010, Irganox 1076, Sumilizer GS, or the like. These may be used alone or in combination of two or more.

  The phosphorus-based antioxidant is not particularly limited, but specifically, tris (2,4-di-tert-butylphenyl) phosphite, bis (2,4-bis (1,1-dimethylethyl) ) -6-Methylphenyl) ethyl ester phosphorous acid, tetrakis (2,4-di-tert-butylphenyl) (1,1-biphenyl) -4,4′-diylbisphosphonite, bis (2,4 -Di-tert-butylphenyl) pentaerythritol diphosphite, bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, bis (2,4-dicumylphenyl) pentaerythritol- Diphosphite, tetrakis (2,4-tert-butylphenyl) (1,1-biphenyl) -4,4′-diylbisphospho , Di-tert-butyl-m-cresyl-phosphonite, tris (2-((2,4,8,10-tetra-tert-butyldibenzo [d, f] [1,3,2] dioxaphosphe Fin-6-yl) oxy) ethyl) amine and the like. These may be used alone or in combination of two or more.

  As the phosphorus-based antioxidant, a commercially available phosphorus-based antioxidant may be used, and such a commercially available phosphorus-based antioxidant is not particularly limited, but specific examples thereof include Irgafos 168, Irgafos 12, and Irgafos. ADK STAB 329K, ADK STAB PEP-36, ADK STAB PEP-8 (all trade names, manufactured by ADEKA Corporation), Sandstub P-EPQ (trade name, manufactured by Clariant Japan Co., Ltd.) ), Weston 618, Weston 619G, Ultranox 626 (all trade names, manufactured by GE), Sumilizer GP (trade name, manufactured by Sumitomo Chemical Co., Ltd.) and the like. These may be used alone or in combination of two or more.

The combination of the ultraviolet absorber and the antioxidant in the present invention is preferably a combination of a benzotriazole-based ultraviolet absorber and a hindered phenol-based antioxidant in terms of compatibility.
When the (meth) acrylic resin composition contains an antioxidant, the content thereof is 0.005 to 0.005 parts by mass based on a total of 100 parts by mass of the (meth) acrylic resin (A) and the acrylic rubber particles (B). 10 parts by mass is preferable, 0.008 to 1 part by mass is more preferable, and 0.01 to 0.2 part by mass is further preferable. When the content of the antioxidant is within the above range, a molded article comprising the (meth) acrylic resin composition can be given sufficient antioxidant performance.

<Production conditions for (meth) acrylic resin composition>
The production of the (meth) acrylic resin composition of the present invention comprises the steps of melt-kneading the (meth) acrylic resin (A) and the acrylic rubber particles (B) in a kneading section of an extruder, and A step of melt-filtration with an arranged polymer filter, wherein the temperature (Ta) of the kneading section of the extruder and the temperature (Tb) of the polymer filter are adjusted to the following conditions (1), (2) and (3). ).
<Conditions>
(1) -10 ° C ≦ Tb−Ta ≦ 30 ° C
(2) 200 ° C ≦ Ta <280 ° C
(3) 200 ° C ≦ Tb <280 ° C.

[Condition (1)]
In the present invention, the production is performed under the condition that the temperature (Ta) of the kneading section of the extruder and the temperature (Tb) of the polymer filter satisfy -10 ° C ≦ Tb−Ta ≦ 30 ° C. When (Tb-Ta) satisfies the above range, it is possible to stabilize the state of the resin and improve continuous productivity while suppressing thermal deterioration of the resin composition.
(Tb-Ta) is preferably 0 ° C <Tb-Ta ≦ 30 ° C, more preferably 0 ° C <Tb-Ta ≦ 25 ° C, and 5 ° C ≦ Tb-Ta ≦ 22 ° C. Is more preferable, and it is particularly preferable that 15 ° C. ≦ Tb−Ta ≦ 22 ° C. If each of the temperatures is out of the above range, the state of the resin in the process is not stable, making continuous production difficult, or the resin is likely to deteriorate due to overheating. In the present invention, the relationship between the temperature (Ta) of the kneading section and the temperature (Tb) of the polymer filter may satisfy the condition (1), but Tb is preferably larger than Ta.

[Condition (2)]
In the present invention, the temperature (Ta) of the kneading section of the extruder is set to 200 ° C ≦ Ta <280 ° C. When the temperature (Ta) of the kneading section of the extruder is within the above range, it becomes possible to suppress the thermal deterioration of the resin composition and the vent up of the extruder. From the above viewpoint, the temperature (Ta) of the kneading section is preferably 200 ° C ≦ Ta ≦ 270 ° C, more preferably 220 ° C ≦ Ta ≦ 260 ° C, and 225 ° C ≦ Ta ≦ 245 ° C. Is more preferred.
In the present invention, the kneading unit temperature (Ta) is the set temperature of the cylinder of the extruder, and when there are a plurality of set temperatures of the cylinder of the extruder, the lowest cylinder set temperature is Ta.

[Condition (3)]
In the present invention, the temperature (Tb) of the polymer filter is set to 200 ° C. ≦ Tb <280 ° C. When the temperature (Tb) of the polymer filter is within the above range, thermal degradation of the resin composition can be suppressed, and the pressure difference between the inlet and the outlet of the polymer filter can be adjusted. . From the above viewpoint, the temperature (Tb) of the polymer filter is preferably 200 ° C. ≦ Tb ≦ 270 ° C., more preferably 220 ° C. ≦ Tb ≦ 260 ° C., and 225 ° C. ≦ Tb ≦ 255 ° C. Is more preferred.

(Extruder)
The extruder used in the present invention is not particularly limited, and examples thereof include a single-screw extruder, a twin-screw extruder, and a multi-screw extruder. Among these, a twin-screw extruder is preferred from the viewpoint of efficiently and uniformly dispersing the acrylic rubber particles (B) in the resin composition.

  The L / D of the extruder is preferably from 10 to 100, and more preferably from 15 to 80, from the viewpoint of uniform mixing of the (meth) acrylic resin (A), acrylic rubber particles (B) and additives used. More preferably, it is more preferably 20 to 60. When L / D is 10 or more, it becomes easy to obtain a better kneading state. Further, when the L / D is 100 or less, shear heat generation during kneading can be reduced, and thermal decomposition of the resin composition and additives can be suppressed. Here, L [unit: mm] is the length of the cylinder of the extruder, and D [unit: mm] is the inner diameter of the cylinder of the extruder.

The extruder used in the present invention preferably includes one or more open vents. By using such an extruder, decomposed products and volatile components can be sucked from the open vent portion, and the quality of the obtained resin composition can be improved. In order to suck decomposed matter and the like from the open vent, for example, it is preferable that the open vent is set in a reduced pressure state.
When the pressure is reduced, the pressure is preferably from 1 to 900 hPa, more preferably from 5 to 800 hPa, further preferably from 10 to 500 hPa, and particularly preferably from 20 to 100 hPa. When the pressure at the open vent is 900 hPa or less, the residual amounts of decomposed products and volatile components can be reduced. When the pressure at the open vent is 1 hPa or more, the productivity of the resin composition can be improved.

  A known die can be connected to the extruder according to the shape of the obtained resin composition. For example, by connecting a strand die and cutting the extruded resin composition to a desired length, a granular or columnar resin composition can be obtained.

The method of supplying the raw material of the acrylic resin composition to the extruder is not particularly limited, and all of the raw materials may be supplied to the raw material supply hopper from the weight feeder, or two or more raw materials may be combined. The above-mentioned weight feeder may be used to supply the raw material to the hopper.
When a part or all of the raw materials are mixed to produce a premix, the production method is not particularly limited, and for example, mixing can be performed using a known mixer such as a tumbler or a Henschel mixer.

As an example of the screw configuration of the extruder, a conveying section having a full flight screw segment for conveying the raw material and kneaded material of the resin composition, and a kneading disk for kneading the raw material of the resin composition (such as forward feed, neutral, reverse feed, etc. ) And a kneading section provided with a screw segment having a reverse feeding direction of the molten resin (a screw segment having a reverse spiral winding direction, a reverse flight).
From the viewpoint of uniformly dispersing the acrylic rubber particles (B), it is preferable to have one or more kneading units.
In addition, it is preferable that the transport unit is provided behind the kneading unit that transports the kneaded product of the resin composition to a die unit or the like in order to avoid an increase in resin pressure at the head of the twin-screw extruder.

The cylinder set temperature of the transport unit on the raw material supply side of the kneading unit is preferably lower than the temperature (Ta) of the kneading unit from the viewpoint of preventing thermal deterioration and improving the raw material transportability. When there are two or more kneading units, the lowest temperature among the set temperatures of the kneading units is Ta. The temperature difference between the kneading units in the case of having two or more kneading units is preferably from 0 to 30 ° C, more preferably from 0 to 20 ° C, from the viewpoint of suppressing thermal deterioration and increasing the resin pressure and improving continuous productivity. , 0 to 10 ° C is more preferable.
On the other hand, the cylinder set temperature of the transport section corresponding to the location for transporting the kneaded material of the resin composition to the die section or the like between the kneading sections or behind the kneading section is continuous while suppressing thermal deterioration and increase in resin pressure. From the viewpoint of improving productivity, a temperature higher by 0 to 30 ° C than the kneading part temperature (Ta) is preferable, a temperature higher by 0 to 20 ° C is more preferable, and a temperature higher by 0 to 10 ° C is further preferable.

  In the present invention, from the viewpoint of preventing deterioration of the (meth) acrylic resin composition, it is preferable to perform melt-kneading while passing an inert gas into the extruder, and it is more preferable to perform melt-kneading while passing nitrogen.

<Polymer filter>
In the present invention, a polymer filter is provided behind the extruder to remove foreign substances. Examples of the polymer filter include a candle type polymer filter and a leaf disk type polymer filter. In the present invention, the extruder and the polymer filter may be directly connected, or another device may be connected between the extruder and the polymer filter. It is preferable to connect. Here, the case where there is a single pipe for connection between them is also referred to as direct connection.

[Candle type polymer filter]
The type of the candle type polymer filter is not particularly limited, and a known type such as a corrugated type or a pleated type can be used. The pleats in the pleat type may extend in the radial direction of the filter element, or may be so-called spiral pleats extending obliquely to the radial direction and having a curved or arched cross-sectional shape.

  One or more candle-type polymer filters are installed in the flow path, that is, in the housing. There is no particular limitation on the number of polymer filters, but by increasing the number, the filtration area increases and the life of the polymer filter can be extended. In the present invention, a channel provided with four polymer filters in a housing, that is, a housing can be suitably used.

  The length of the candle-type polymer filter is preferably from 300 to 3,000 mm, more preferably from 300 to 2,000 mm, and still more preferably from 300 to 1,000 mm, from the viewpoint of the filtration area and the drift in the polymer filter.

[Leaf disk type polymer filter]
The shape of the leaf disk type polymer filter is not limited.For example, an internal flow type having a plurality of resin circulation ports and having a resin flow path in the center pole, or an external flow type having a resin flow path on the outer surface of the center pole. It can be any of the types.
One or two or more leaf disk type polymer filters are installed in a flow path, that is, a housing. The length of the polymer resin from the first sheet to the last sheet in the direction of flow of the molten resin is preferably from 300 to 3,000 mm, and more preferably from 300 to 2,000 mm, from the viewpoint of the filtration area and the drift in the polymer filter. More preferably, it is still more preferably from 300 to 1,000 mm.

(Filter material for polymer filter)
The material of the filter medium of the polymer filter is not particularly limited, but stainless steel is preferable from the viewpoint of rust resistance, corrosion resistance, strength, and the like, SUS304 and SUS316L are more preferable, and SUS316L is further preferable from the viewpoint of corrosion resistance.
Examples of the form of the filter medium of the polymer filter include a powder sintered body and a fiber sintered body. These may be used in combination.

(Filtration accuracy)
The filtration accuracy of the polymer filter is preferably from 0.5 to 30 μm, more preferably from 3 to 20 μm, and still more preferably from 5 to 15 μm, from the viewpoint of the balance between productivity and foreign matter size. By setting the filtration accuracy to 30 μm or less, it is possible to effectively remove foreign substances. On the other hand, by setting the filtration accuracy to 0.5 μm or more, it is possible to suppress shear heat generation when passing the (meth) acrylic resin composition in a molten state and to suppress thermal deterioration.

(Filtration area)
The filtration area with respect to the amount of resin processed per unit time in the polymer filter is not particularly limited, and can be appropriately set according to the amount of resin composition processed. The filtration area is preferably 0.001~0.15m is ² / (kg / hour), more preferably 0.002~0.05m ² / (kg / hour), 0.003 More preferably, it is 0.01 m ² / (kg / hour).

  The pressure difference between the inflow port and the outflow port of the polymer filter is preferably 1 to 10 MPa, more preferably 2 to 9 MPa, and even more preferably 4 to 8 MPa. When the differential pressure is less than 1 MPa, the flow of the resin composition in the polymer filter becomes uneven, and there is a concern that the resin composition may deteriorate and foreign matter may be generated. When the differential pressure exceeds 10 MPa, there is a concern that the filter element may be damaged, which is not preferable.

[(Meth) acrylic resin composition and molded article using the same]
The (meth) acrylic resin composition of the present invention is manufactured by the manufacturing method of the present invention and has little thermal deterioration. The (meth) acrylic resin composition of the present invention may be in the form of a pellet or the like for the purpose of improving convenience during transportation and the like. The molded article of the present invention uses the (meth) acrylic resin composition of the present invention, and can be suitably used as a film, sheet, or laminate.

  The film obtained by the present invention can be used for the following various applications. For example, automotive interior / exterior, PC interior / exterior, mobile phone interior / exterior, solar cell interior / exterior, solar cell backsheet, glasses, contact lens, endoscope lens, medical equipment field such as medical supplies requiring sterilization, road Signs, bathroom equipment, flooring, road translucent boards, double glass lenses, daylighting windows, carports, lighting covers, construction materials such as sizing for building materials, microwave cooking containers (tableware), housing for home appliances, It can be used for toys, sunglasses, stationery and the like. It can also be used as a substitute for a molded product using a transfer foil sheet.

  In particular, the film obtained by the present invention is suitable for an optical film in that it has excellent heat resistance and optical properties, and can be used for various optical members. For example, imaging fields for cameras, VTRs, photographic lenses for projectors, finders, filters, prisms, Fresnel lenses, lens covers, etc .; lens fields for optical disc pickup lenses in CD players, DVD players, MD players, etc .; Optical recording field for optical discs such as MD, MD, etc .; Front panel of liquid crystal screen of terminals such as mobile phones, smartphones, tablets, etc .; Vehicle field such as automobile headlight tail lamp lens, inner lens, instrument cover, sunroof; Liquid crystal display film such as light guide plate, diffusion plate, back sheet, reflection sheet, polarizing film transparent resin sheet, retardation film, light diffusion film, prism sheet, optical isotropic film, polarizer protection film, transparent conductive film, etc. Etc. Around a liquid crystal display device; a field of information equipment such as a surface protection film; a periphery of an organic EL device as a film for organic EL; a field of optical communication such as an optical fiber, an optical switch, an optical connector; an optical lens; Applicable to application.

  The film obtained by the present invention can be used by laminating it on metal, plastic or the like. As a method of laminating the film, lamination molding, wet lamination in which an adhesive is applied to a metal plate such as a steel plate, and then the film is placed on a metal plate and dried and bonded, dry lamination, extrusion lamination, hot melt lamination, or the like is used. No.

  As a method of laminating the film obtained by the present invention on a plastic part, the film was placed in a mold, and insert molding or laminating injection press molding in which a resin was filled by injection molding, or the film was preformed. In-mold molding or the like, which is arranged in a mold later and filled with resin by injection molding, may be mentioned.

  The laminate of the film obtained by the present invention can be used as a substitute for painting such as automobile interior materials and automobile exterior materials, building materials such as window frames, bathroom equipment, wallpaper, floor materials, daily miscellaneous goods, furniture and electric equipment. Housings, housings for OA equipment such as facsimile machines, notebook computers, copy machines, etc., front panels of liquid crystal screens of terminals such as mobile phones, smartphones, tablets, etc., illumination lenses, automobile headlights, optical lenses, optical fibers, optical disks, and liquid crystals It can be used for optical members such as light guide plates for use, parts of electric or electronic devices, medical supplies requiring to be sterilized, toys or recreational items.

  Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to these Examples.

[Measuring method]
<Content of methyl methacrylate unit>
The content of the methyl methacrylate unit was calculated as the charged amount of the methyl methacrylate monomer relative to the total charged value of the monomers.

<Weight average molecular weight (Mw)>
The weight average molecular weight (Mw) was determined by GPC (gel permeation chromatography) in terms of standard polystyrene equivalent molecular weight. The measuring device and conditions are as follows.
・ Equipment: GPC system “HLC-8320” manufactured by Tosoh Corporation
-Separation column: "TSKgel SuperMultipore HZM-M" and "Super HZ4000" manufactured by Tosoh Corporation-Detector: "RI-8020" manufactured by Tosoh Corporation
・ Eluent: tetrahydrofuran ・ Eluent flow rate: 0.35 ml / min ・ Sample concentration: 8 mg / 10 ml
・ Column temperature: 40 ℃

<Glass transition temperature (Tg)>
The glass transition temperature was measured according to JIS K7121: 2012. That is, the DSC curve was measured by differential scanning calorimetry under the condition that the sample was once heated to 200 ° C., then cooled to room temperature, and then heated from room temperature to 200 ° C. at 10 ° C./min. The midpoint glass transition temperature determined from the DSC curve measured at the time of the second temperature rise was defined as the glass transition temperature in the present invention.

<Average particle size>
The average particle size is determined by diluting the latex containing the sample particles 200 times with water and using a laser diffraction scattering type particle size distribution measuring device (manufactured by HORIBA, Ltd., device name “LA-950V2”) at 25 ° C. The diluent was analyzed and the particle size was measured. At this time, the absolute refractive indexes of the acrylic rubber particles and water were set to 1.4900 and 1.3333, respectively.

<Graft rate>
The graft ratio is determined by immersing the acrylic rubber particles in acetone, centrifuging the particles with a centrifugal separator, removing the acetone-soluble matter and drying, and measuring the mass of the acetone-insoluble matter obtained by the following formula (a). It was calculated from:
Graft ratio = {[mass of acetone-insoluble component−mass of crosslinked rubber polymer component (I)] / mass of crosslinked rubber polymer component (I)} × 100 (a)
The mass of the crosslinked rubber polymer component (I) was the sum of the masses of the monomers of the crosslinked rubber polymer component (I) in the polymerization. In the case where the acrylic rubber particles further have the inner layer inside the elastic layer, the mass of the crosslinked rubber polymer component (I) in the above formula (a) is the mass of the crosslinked rubber polymer component (I) and the polymer component. It was the total of the mass of the monomer of (i).

[Evaluation method]
<Continuous productivity [torque]>
The torque value (current output value of the screw motor) displayed on the monitor was observed for 30 seconds, and the average value was defined as the torque value (%).
In view of torque fluctuation during continuous production, it is preferable that the ratio is lower than 80%. Therefore, when the ratio is lower than 80%, continuous productivity is considered to be good.

<Acid value>
0.8 g of the sample obtained in each of Examples and Comparative Examples was dissolved in chloroform overnight, and 50 mL of the obtained solution was used as a BTB solution as an indicator. A 0.01 mol / L potassium hydroxide solution was used until the solution became pale yellow. Was added dropwise. The acid value was calculated from the drop amount (A mL) of potassium hydroxide by the following formula.
(Acid value) = A × 10 / 0.8 (μmol / g)
In the present invention, from the viewpoint of suppressing thermal deterioration of the (meth) acrylic resin composition, the acid value is preferably 5.0 μmol / g or less.

[Production method]
<Production Example 1: Production of (meth) acrylic resin (A-1)>
To 99.3 parts by mass of methyl methacrylate and 0.7 parts by mass of methyl acrylate, a polymerization initiator [2,2′-azobis (2-methylpropionitrile), hydrogen abstraction ability: 1%, 1 hour half-life temperature: 83 ° C.], 0.008 parts by mass and 0.26 parts by mass of a chain transfer agent (n-octyl mercaptan) were added and dissolved to obtain 3000 kg of a raw material liquid.
100 parts by mass of ion-exchanged water, 0.03 parts by mass of sodium sulfate, and 0.45 parts by mass of a suspending / dispersing agent were mixed to obtain a 6000 kg mixed solution. The mixed liquid and the raw material liquid (total of 9000 kg) were charged into a pressure-resistant polymerization tank, and the polymerization reaction was started at a temperature of 70 ° C. while stirring under a nitrogen atmosphere. After 3 hours from the start of the polymerization reaction, the temperature was raised to 90 ° C., and stirring was continued for 1 hour to obtain a liquid in which the bead copolymer was dispersed. The polymer slightly adhered to the wall surface of the polymerization tank or the stirring blade, but did not foam and the polymerization reaction proceeded smoothly.
The obtained copolymer dispersion liquid is washed with an appropriate amount of ion-exchanged water, the beaded copolymer is taken out by a bucket type centrifugal separator, dried with a hot air drier at 80 ° C. for 12 hours, and the beads ) An acrylic resin (A-1) was obtained.
The obtained (meth) acrylic resin (A-1) had a methyl methacrylate unit content of 99.3% by mass, a weight average molecular weight (Mw) of 92,000, and a glass transition temperature of 120 ° C. Was.

<Production Example 2: Production of acrylic rubber particles (B-1)>
(1) Synthesis of Inner Layer In a reactor equipped with a stirrer, a thermometer, a nitrogen gas inlet tube, a monomer inlet tube, and a reflux condenser, 1050 parts by mass of ion-exchanged water, sodium polyoxyethylene tridecyl ether acetate were added. 0.3 parts by mass and 0.7 parts by mass of sodium carbonate (total 2,100 kg) were charged, and the inside of the reactor was sufficiently replaced with nitrogen gas. Then, the internal temperature was set to 80 ° C. Thereto was added 0.25 parts by mass of potassium persulfate, and the mixture was stirred for 5 minutes. To this, 245 parts by mass of a monomer mixture composed of 95.4% by mass of methyl methacrylate, 4.4% by mass of methyl acrylate and 0.2% by mass of allyl methacrylate were continuously dropped over 60 minutes. After completion of the dropwise addition, a polymerization reaction was further performed for 30 minutes so that the polymerization conversion rate became 98% or more.

(2) Synthesis of Elastic Layer Next, 0.32 parts by mass of potassium persulfate was charged into the reactor and stirred for 5 minutes. Thereafter, 315 parts by mass of a monomer mixture consisting of 80.5% by mass of n-butyl acrylate, 17.5% by mass of styrene and 2% by mass of allyl methacrylate were continuously dropped over 60 minutes. After completion of the dropwise addition, a polymerization reaction was further performed for 30 minutes so that the polymerization conversion rate became 98% or more.

(3) Synthesis of Outer Layer Next, 0.14 parts by mass of potassium persulfate was charged into the reactor and stirred for 5 minutes. Thereafter, 140 parts by mass of a monomer mixture composed of 95.2% by mass of methyl methacrylate, 4.4% by mass of methyl acrylate and 0.4% by mass of n-octylmercaptan were continuously dropped over 30 minutes. After the completion of the dropwise addition, the polymerization reaction was further performed for 60 minutes so that the polymerization conversion rate became 98% or more.

  After the latex containing the acrylic rubber particles (B-1) was obtained by the above operation, the latex containing the acrylic rubber particles (B-1) was frozen and solidified. Then, it was washed with water and dried to obtain acrylic rubber particles (B-1). The average particle size of the particles was 0.23 μm, and the graft ratio was 23%.

[Examples 1-3, Comparative Examples 1-2]
The (meth) acrylic resin compositions of Examples 1 to 3 and Comparative Examples 1 and 2 were produced according to the following methods, and continuous productivity and oxidation were evaluated according to the above-described evaluation methods. Table 1 shows the results.
<Example 1>
80 parts by mass of the (meth) acrylic resin (A-1) obtained in Production Example 1, 20 parts by mass of the acrylic rubber particles (B-1) obtained in Production Example 2, and an ultraviolet absorbent (trade name: "ADK STAB LA-31RG") ", 2.2 parts by mass of ADEKA Corporation, 1.5 parts by mass of a polymer processing aid (trade name" Paraloid K125P ", manufactured by Dow Chemical Japan KK), and an antioxidant (trade name" Irganox 1010 ") , BASF Japan Co., Ltd.) and 0.1 parts by mass of a 58 mm diameter co-rotating twin-screw extruder (trade name "TEM-58SS", manufactured by Toshiba Machine Co., Ltd.) having an L / D of 41.5. The mixture was put into a hopper, melt-kneaded under the kneading conditions (Ta: 230 ° C.) shown in Table 1 while passing nitrogen through the vent part at a pressure of 50 hPa, filtered through a polymer filter (Tb: 230 ° C.), and extruded from a die. It was obtained (meth) acrylic resin composition (C-1) by Rukoto. Neither excess torque nor vent-up, which are indicators of continuous productivity, occurred. The acid value of the (meth) acrylic resin composition (C-1) was 4.7 μmol / g.
In Example 1, the production was performed using an apparatus in which an extruder and a polymer filter were directly connected.

<Example 2>
A (meth) acrylic resin composition (C-2) was obtained in the same manner as in Example 1 except that the mixture was filtered with a polymer filter (Tb: 250 ° C). Neither excess torque nor vent-up, which are indicators of continuous productivity, occurred. The acid value of the (meth) acrylic resin composition (C-2) was 4.6 μmol / g.

<Example 3>
(Meth) acrylic resin composition in the same manner as in Example 1 except that the mixture is melt-kneaded under nitrogen under kneading conditions (Ta: 250 ° C.), filtered through a polymer filter (Tb: 250 ° C.), and then extruded from a die. (C-3) was obtained. Neither excess torque nor vent-up, which are indicators of continuous productivity, occurred. The acid value of the (meth) acrylic resin composition (C-3) was 5.0 μmol / g.

<Comparative Example 1>
The (meth) acrylic resin composition was melt-kneaded under nitrogen under kneading conditions (Ta: 210 ° C.), filtered through a polymer filter (Tb: 250 ° C.), and extruded from a die in the same manner as in Example 1. (C′-1) was obtained. No vent-up, which is an indicator of continuous productivity, occurred, but the torque value was 80%. Further, the acid value of the (meth) acrylic resin composition (C′-1) was 4.6 μmol / g.

<Comparative Example 2>
A (meth) acrylic resin composition (C′-2) was obtained in the same manner as in Example 1 except that the mixture was filtered with a polymer filter (Tb: 265 ° C.). Neither the torque value excess nor vent up, which are indicators of continuous productivity, occurred, but the acid value of the (meth) acrylic resin composition (C′-2) was 5.2 μmol / g.

In Examples 1 to 3, the difference (Tb−Ta) between the set temperature Ta of the kneading section of the extruder and the set temperature Tb of the polymer filter was 30 ° C. or less, and each temperature was adjusted to a predetermined temperature range. Therefore, as compared with Comparative Examples 1 and 2, thermal deterioration of the kneaded resin could be suppressed, and continuous productivity was better.
On the other hand, in Comparative Examples 1 and 2 in which (Tb−Ta) was 30 ° C. or more, the resin composition was thermally degraded or continuous productivity was reduced.

Claims (12)

A method for producing a (meth) acrylic resin composition containing (meth) acrylic resin (A) and acrylic rubber particles (B),
A step of melt-kneading the (meth) acrylic resin (A) and the acrylic rubber particles (B) in a kneading section of an extruder;
Melt-filtering with a polymer filter disposed behind the extruder,
A method for producing a (meth) acrylic resin composition, wherein the temperature (Ta) of the kneading section of the extruder and the temperature (Tb) of the polymer filter satisfy the following conditions (1), (2) and (3).
<Conditions>
(1) -10 ° C ≦ Tb−Ta ≦ 30 ° C
(2) 200 ° C ≦ Ta <280 ° C
(3) 200 ° C ≦ Tb <280 ° C.   The method for producing a (meth) acrylic resin composition according to claim 1, wherein the condition (1) satisfies 0 ° C <Tb-Ta ≦ 30 ° C.   The method for producing a (meth) acrylic resin composition according to claim 1 or 2, wherein the acid value of the (meth) acrylic resin composition is 5.0 µmol / g or less.   The method for producing a (meth) acrylic resin composition according to any one of claims 1 to 3, wherein the (meth) acrylic resin (A) has a glass transition temperature of 80C or more.   The (meth) acrylic resin composition according to any one of claims 1 to 4, wherein the (meth) acrylic resin composition contains 5 to 95% by mass of the (meth) acrylic resin (A) and 95 to 5% by mass of the acrylic rubber particles (B). A method for producing a (meth) acrylic resin composition.   The method for producing a (meth) acrylic resin composition according to claim 1, wherein the filtration accuracy of the polymer filter is 0.5 to 30 μm.   The method for producing a (meth) acrylic resin composition according to any one of claims 1 to 6, wherein the polymer filter is a candle type polymer filter or a leaf disk type polymer filter.   The method for producing a (meth) acrylic resin composition according to claim 7, wherein the length of the candle-type polymer filter is 300 to 3,000 mm.   The method for producing a (meth) acrylic resin composition according to any one of claims 1 to 8, wherein the extruder and the polymer filter are directly connected.   A (meth) acrylic resin composition produced by the production method according to claim 1.   A molded article using the (meth) acrylic resin composition according to claim 10.   The molded article according to claim 11, wherein the molded article is a film or a sheet.