JP2007276310A - Method of manufacturing methacrylic resin laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a methacrylic resin laminate having excellent resistance to scratching and impacts, transparency and productivity. <P>SOLUTION: The manufacturing method comprises hardening a curable composition to form a hard coat film and hardening a polymerizable mixture which comprises 70-96 pts.mass of a radical-polymerizable monomer based on methyl methacrylate or a mixture of the monomer with a (co)polymer of the monomer polymerized partially and 30-4 pts.mass of a multi-stage-polymerized copolymer containing a rubber-like copolymer obtained by one- or multi-stage polymerization and having a cross-linked structure, on the surface of the hard coat film, so as to form a resin base layer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing a methacrylic resin laminate.

Methacrylic resin plates have excellent transparency and surface gloss, good weather resistance, mechanical properties, etc., so they are used in a wide range of fields such as lighting fixtures, signboards, various building materials, sound insulation plates, and various displays. Yes.
However, methacrylic resin plates are not always sufficient in terms of strength against impact (impact resistance). In addition, the methacrylic resin plate is not sufficient in terms of scratch resistance (abrasion resistance) on the surface.
Against this background, various proposals regarding methacrylic resin plates have been made.

As a method for improving the impact resistance of a methacrylic resin plate, for example, the following method is disclosed.
(1) A multi-stage polymer including an elastomer layer (including a rubbery copolymer) of about 4 to 90% by mass and a hard thermoplastic polymer such as a methacrylic resin of about 10 to 96% by mass are mixed. The manufacturing method by the casting method etc. of an impact-resistant composition is disclosed (refer patent document 1).
(2) Hard to rubbery copolymer having a crosslinked structure and an average particle size of 0.1 to 1 μm in 100 parts by mass of methyl methacrylate resin or methyl methacrylate resin containing 50% by mass or more of methyl methacrylate unit A methacrylic resin cast plate in which 2 to 30 parts by mass of a graft copolymer (multi-stage copolymer) obtained by graft polymerization of a resin component is dispersed as a rubbery copolymer is disclosed (patent) Reference 2).
(3) 5 to 50 parts by mass of a methyl methacrylate polymer having a viscosity average molecular weight of 10,000 to 200,000 is dissolved in 100 parts by mass of a monomer having methyl methacrylate as a main component. A method for producing a methacrylic resin cast plate is disclosed in which syrup in which 1 to 50 parts by mass are dispersed is injected into a cell and polymerized (see Patent Document 3).

In general, the following methods are known in order to prevent the surface of the substrate from being scratched.
(4) A method of providing a hard coat layer (a scratch-resistant film) with a crosslinked film on the surface of a substrate is disclosed (for example, see Patent Document 4).

Furthermore, as a method for improving the scratch resistance and impact resistance of the methacrylic resin plate, for example, the following methods are disclosed.
(5) An acrylic resin film is disclosed in which a scratch-resistant film obtained by curing a curable coating is formed on the surface of an acrylic resin film in which rubber particles are dispersed in a methacrylic resin. Specifically, acrylic rubber and methacrylic resin pellets are mixed, melted and kneaded with a twin screw extruder, and pelletized using a single screw extruder and brought into contact with a roll. Acrylic resin film was then created, and then the surface of the acrylic resin film was coated with a curable paint with a bar coater, dried and cured, thereby improving the scratch resistance and impact resistance. An acrylic resin film is obtained (see Patent Document 5).
Japanese Patent Publication No.55-27576 Japanese Patent No. 2648179 Japanese Patent No. 3508251 Japanese Patent Laid-Open No. 2002-6676 JP 2004-143365 A

  However, in the methods (1) to (3), there is a problem that the scratch resistance (scratch resistance) on the surface of the methacrylic resin plate is deteriorated as the elastic modulus is lowered by the blending of the rubbery copolymer.

In the method (4), although the scratch resistance can be improved, the improvement in impact resistance is not disclosed.
In the method (5), the impact resistance is not yet sufficient, and in order to further impart the impact resistance, it is necessary to add a relatively large amount of acrylic rubber.
Further, the method (5) has a problem that productivity is low because it has many steps. In addition, there may be a problem that foreign matters are mixed into the cured film during curing after application of the curable coating material, and drying unevenness may occur during drying. Furthermore, in order to obtain a viscosity suitable for moldability to an acrylic resin film, when the average molecular weight of the methacrylic resin is adjusted to be low, cracks may occur during cutting or molding of the acrylic resin film, There is a problem that the processability is inferior, such as insufficient smoothness.

  Moreover, although the casting polymerization (cast polymerization) method is also described in the above-mentioned patent document, the curability of the cured product is not sufficient because the treatment such as oxygen blocking is not performed at the time of forming the cured film. And the intended scratch resistance is difficult to obtain. In addition, when syrup or the like is injected into the cell, it has not yet been solved.

  An object of the present invention is to provide a method for producing a methacrylic resin laminate excellent in scratch resistance, impact resistance, transparency and productivity.

  In the method for producing a methacrylic resin laminate of the present invention, the curable composition (a-1) is cured to form a hard coat film (A), and methyl methacrylate is formed on the surface of the hard coat film (A). The radical polymerizable monomer (b-1) as a main component, or a (co) polymer in which a part of the radical polymerizable monomer (b-1) is polymerized and the radical polymerizable monomer (b -1) and 70 to 96 parts by mass of a multi-stage copolymer (b-2) containing 30 to 4 parts by mass of a rubbery copolymer having a crosslinked structure obtained by at least one stage of polymerization. The polymerizable mixture (P) is cured to form the resin base material layer (B).

  The method for producing a methacrylic resin laminate of the present invention comprises a coating step of interposing a curable composition (a-1) between a mold and a resin film, and a curable composition (a-1) on the mold. After irradiating active energy rays through the resin film, curing the curable composition (a-1) to form a hard coat film (A), and after peeling the resin film, Provided on the mold, the base material (S) facing the mold, and the periphery of the mold and the base material (S) so that the hard coat film (A) formed in the curing step becomes the inner surface A cell production process for producing a cell comprising a gasket, a polymerization process for injecting the polymerizable mixture (P) into the cell to perform cast polymerization, and after the cast polymerization is completed, Film (A) and resin base layer (B) And a step of taking out the laminate having a.

  In the method for producing a methacrylic resin laminate of the present invention, the curing step of forming the hard coat film (A) on the mold and the base material (S), and the hard coat film (A) are the inner surfaces. A cell production step of producing a cell comprising the mold, a base material (S) facing the mold, and a gasket provided on a peripheral portion of the mold and the base material (S), A polymerization step for injecting the polymerizable mixture (P) to perform cast polymerization, and after completion of the cast polymerization, a laminate having hard coat films (A) on both surfaces of the resin base material layer (B) from the cell. And a step of taking out.

  In the method for producing a methacrylic resin laminate of the present invention, the hard coat film (A) is formed by curing the curable composition (a-1) on one or both surfaces of the pair of endless belts facing each other. The polymerizable mixture (P) is continuously provided in a space surrounded by the endless belt on which the hard coat film (A) is formed and each gasket that runs following both end portions of the endless belt. It is preferable to carry out casting polymerization and perform casting polymerization, and continuously take out the laminate having the hard coat film (A) and the resin base material layer (B) from the endless belt.

  In the method for producing a methacrylic resin laminate of the present invention, the amount of acetone insoluble in the resin base material layer (B) is 1.3 times or more of the amount of acetone insoluble in the multistage polymerization copolymer (b-2). It is preferable that

  According to the method for producing a methacrylic resin laminate of the present invention, a methacrylic resin laminate excellent in scratch resistance, impact resistance, transparency and productivity can be produced.

In the method for producing a methacrylic resin laminate of the present invention, the curable composition (a-1) is cured to form a hard coat film (A), and methyl methacrylate is formed on the surface of the hard coat film (A). The radical polymerizable monomer (b-1) as a main component, or a (co) polymer in which a part of the radical polymerizable monomer (b-1) is polymerized and the radical polymerizable monomer (b -1) 70-96 parts by mass of the mixture and 30-4 parts by mass of a multistage polymerization copolymer (b-2) containing a rubbery copolymer having at least one cross-linked structure (b-2) In this method, the resin base material layer (B) is formed by curing P).
Hereinafter, after explaining the curable composition (a-1) and the polymerizable mixture (P), the production method of the methacrylic resin laminate of the present invention will be explained according to the production procedure.

[Curable composition (a-1)]
The curable composition (a-1) is not particularly limited as long as it is cured by irradiation with active energy rays such as ultraviolet rays or heating, and in particular, two or more acryloyl groups and methacryloyl. Preferred examples include crosslinkable curable liquids containing groups; silicone-based and melamine-based crosslinkable curable liquids, and the like.
Among these, a photocurable composition is preferable, and a polymerizable compound (a-1-1) having at least two (meth) acryloyloxy groups in the molecule (hereinafter referred to as “component (a-1-1)”). And a photopolymerization initiator (a-1-2) (hereinafter sometimes referred to as “component (a-1-2)”) are more preferable. The mixture exhibits high curability when irradiated with active energy rays such as ultraviolet rays, and has a good curing rate. Further, sufficient curability can be obtained even when the active energy ray is irradiated through the resin film or the active energy ray is irradiated without performing treatment such as oxygen blocking.

Polymerizable compound (a-1-1)
The polymerizable compound (a-1-1) is a crosslinking reactive compound having at least two (meth) acryloyloxy groups in the molecule, and the residue bonded to each (meth) acryloyloxy group is a hydrocarbon. A group or a derivative thereof.
The molecule of the polymerizable compound (a-1-1) can contain an ether bond, a thioether bond, an ester bond, an amide bond, a urethane bond and the like. In addition, (meth) acryl means “acryl” and / or “methacryl”.
Preferred examples of the polymerizable compound (a-1-1) include esterified products obtained from 1 mol of polyhydric alcohol and 2 mol or more of (meth) acrylic acid or derivatives thereof; A linear esterified product having two or more (meth) acryloyloxy groups in one molecule, obtained from a monovalent carboxylic acid or an anhydride thereof and (meth) acrylic acid or a derivative thereof; a polyester obtained by trimerization A compound obtained by reacting 3 moles or more of an acrylic monomer having active hydrogen per mole of isocyanate can be exemplified.
Specific examples of the polymerizable compound (a-1-1) are shown below.

  Di (meth) acrylates of polyethylene glycol such as diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate; 1,4-butanediol di (meth) acrylate, 1,6 -Hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, pentaglycerol tri (meth) acrylate, pentaerythritol tri (Meth) acrylate, pentaerythritol tetra (meth) acrylate, glycerin tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol Tora (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tripentaerythritol tetra (meth) acrylate, tripentaerythritol penta (meth) acrylate, tripentaerythritol hexa (meth) acrylate And esterified products obtained from 1 mol of polyhydric alcohol such as tripentaerythritol hepta (meth) acrylate and 2 mol or more of (meth) acrylic acid.

 Also, malonic acid / trimethylolethane / (meth) acrylic acid, malonic acid / trimethylolpropane / (meth) acrylic acid, malonic acid / glycerin / (meth) acrylic acid, malonic acid / pentaerythritol / (meth) acrylic acid Succinic acid / trimethylolethane / (meth) acrylic acid, succinic acid / trimethylolpropane / (meth) acrylic acid, succinic acid / glycerin / (meth) acrylic acid, succinic acid / pentaerythritol / (meth) acrylic acid, Adipic acid / trimethylolethane / (meth) acrylic acid, adipic acid / trimethylolpropane / (meth) acrylic acid, adipic acid / glycerin / (meth) acrylic acid, adipic acid / pentaerythritol / (meth) acrylic acid, glutar Acid / trimethylolethane / (meth) acrylic acid Glutaric acid / trimethylolpropane / (meth) acrylic acid, glutaric acid / glycerin / (meth) acrylic acid, glutaric acid / pentaerythritol / (meth) acrylic acid, sebacic acid / trimethylolethane / (meth) acrylic acid, sebacine Acid / trimethylolpropane / (meth) acrylic acid, sebacic acid / glycerin / (meth) acrylic acid, sebacic acid / pentaerythritol / (meth) acrylic acid, fumaric acid / trimethylolethane / (meth) acrylic acid, fumaric acid / Trimethylolpropane / (meth) acrylic acid, fumaric acid / glycerin / (meth) acrylic acid, fumaric acid / pentaerythritol / (meth) acrylic acid, itaconic acid / trimethylolethane / (meth) acrylic acid, itaconic acid / Trimethylolpropane / (meth) ac Acid, itaconic acid / glycerin / (meth) acrylic acid, itaconic acid / pentaerythritol / (meth) acrylic acid, maleic anhydride / trimethylolethane / (meth) acrylic acid, maleic anhydride / trimethylolpropane / (meta ) From polyhydric alcohols such as acrylic acid, maleic anhydride / glycerin / (meth) acrylic acid, maleic anhydride / pentaerythritol / (meth) acrylic acid and polyhydric carboxylic acids or their anhydrides and (meth) acrylic acid Examples thereof include linear esterified products having two or more (meth) acryloyloxy groups in one molecule.

Polyisocyanates obtained by trimerization (for example, trimethylolpropane toluylene diisocyanate, hexamethylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, xylene diisocyanate, 4,4'-methylenebis (cyclohexyl isocyanate), isophorone diisocyanate, trimethylhexamethylene Diisocyanate and the like) and an acrylic monomer having active hydrogen (for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxy-3-methoxypropyl (meth) acrylate), N-methylol (meta ) Acrylamide, N-hydroxy (meth) acrylamide, 1,2,3-propanetriol-1,3-di (meth) ) Acrylate, 3-acryloyloxy-2-hydroxypropyl (meth) acrylate, etc.) and urethane (meth) acrylate obtained by reacting 3 mol or more of acrylic monomer per mol of polyisocyanate; tris (2-hydroxyethyl) ) Poly [(meth) acryloyloxyethylene] isocyanurate such as di (meth) acrylate and tri (meth) acrylate of isocyanuric acid; known epoxy polyacrylate; known urethane polyacrylate.
As the polymerizable compound (a-1-1) described above, one type may be used alone, or two or more types may be used in combination.

-Photopolymerization initiator (a-1-2)
The photopolymerization initiator (a-1-2) is not particularly limited. For example, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, acetoin, butyroin, toluoin, benzophenone, p- Methoxybenzophenone, 2,2-diethoxyacetophenone, α, α-dimethoxy-α-phenylacetophenone, methylphenylglyoxylate, ethylphenylglyoxylate, 4,4′-bis (dimethylamino) benzophenone, 2-hydroxy- Carbonyl compounds such as 2-methyl-1-phenylpropan-1-one; sulfur compounds such as tetramethylthiuram monosulfide and tetramethylthiuram disulfide; 2,4,6-trimethylbenzoyldiphenyl Examples include ruphosphine oxide and benzoyldiethoxyphosphine oxide.
The photoinitiator (a-1-2) mentioned above may be used individually by 1 type, and may use 2 or more types together.
It is preferable that the addition amount of a photoinitiator (a-1-2) is 0.1-10 mass parts with respect to 100 mass parts of polymeric compounds (a-1-1). The curability of curable composition (a-1) improves that it is 0.1 mass part or more. On the other hand, when it is 10 parts by mass or less, the hard coat film (A) formed after curing tends not to be colored.

-Other components Various additives conventionally used can be added to the curable composition (a-1) according to the purpose.
Examples of the additive include a surfactant, a leveling agent, a dye, a pigment, an antioxidant, an ultraviolet absorber, a stabilizer, a flame retardant, and a plasticizer.
Although the addition amount of an additive can be suitably selected in the range by which the physical property of the hard coat film (A) of the obtained cured film is not impaired, a component (a-1-1), a component (a-1-2), and It is preferable to set it as 10 mass parts or less with respect to a total of 100 mass parts.

[Polymerizable mixture (P)]
In the present invention, in the polymerizable mixture (P), the radical polymerizable monomer (b-1) mainly composed of methyl methacrylate or a part of the radical polymerizable monomer (b-1) is polymerized. A multistage polymerization copolymer comprising 70 to 96 parts by mass of a mixture of the (co) polymer and the radical polymerizable monomer (b-1) and a rubbery copolymer having a crosslinked structure obtained by at least one stage polymerization. It is a mixture with 30-4 mass parts of a polymer (b-2).

  The polymerizable mixture (P) is prepared by, for example, adding a radical polymerizable monomer (b-1) or the radical polymerizable monomer (b-1) to a flask equipped with a stirring rod, a cooling tube, or the like. A mixture of the (co) polymer partially polymerized with the radical polymerizable monomer (b-1) and, if necessary, a chain transfer agent or the like are added, and preferably a rotational speed of 0.5 to While stirring at a stirring speed of 500 rpm, the multistage polymerization copolymer (b-2) is charged and preferably mixed for 0.5 to 24 hours. Thereby, the multistage polymerization copolymer (b-2) can be sufficiently dispersed in the polymerizable mixture (P).

・ Radically polymerizable monomer (b-1)
In the present invention, the radical polymerizable monomer (b-1) is mainly composed of methyl methacrylate.
Here, the “radical polymerizable monomer” refers to a monomer (monomer) capable of radical polymerization.
The “main component” means a monomer contained in 50% by mass or more of all monomers contained in the radical polymerizable monomer (A).

As the radical polymerizable monomer (b-1), methyl methacrylate is essential, and in addition to this, as a monomer copolymerizable therewith, ethyl methacrylate, isopropyl methacrylate, butyl methacrylate, 2-ethylhexyl Methacrylic acid esters other than methyl methacrylate such as methacrylate, phenyl methacrylate and benzyl methacrylate; Acrylic acid esters such as methyl acrylate, ethyl acrylate, butyl acrylate and 2-ethylhexyl acrylate; Non-acrylic acid, methacrylic acid, maleic acid, itaconic acid, etc. Saturated carboxylic acids; acid anhydrides such as maleic anhydride and itaconic anhydride; maleimide derivatives such as N-phenylmaleimide and N-cyclohexylmaleimide; 2-hydroxyethyl acrylate, 2 Hydroxy group-containing monomers such as hydroxyethyl methacrylate and 2-hydroxypropyl methacrylate; Vinyl esters such as vinyl acetate and vinyl benzoate; Vinyl chloride, vinylidene chloride and their derivatives; Nitrogen-containing single quantities such as methacrylamide and acrylonitrile Examples: Epoxy group-containing monomers such as glycidyl acrylate and glycidyl methacrylate; aromatic compounds having an ethylenically unsaturated bond in the molecule such as styrene and α-methylstyrene.
In addition, alkanediol di (meth) acrylate such as ethylene glycol di (meth) acrylate, 1,2-propylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, etc. (Meth) acrylate; polyoxyalkylene such as diethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, triethylene glycol (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate Glycol di (meth) acrylate; polyfunctional polymerizable compound having two or more ethylenically unsaturated bonds in a molecule such as divinylbenzene; at least one polyvalent compound containing an ethylenically unsaturated polycarboxylic acid Vinyl ester prepolymer and the like derived by acrylic modified terminal epoxy groups; unsaturated polyester prepolymer derived from a carboxylic acid of at least one diol with.
The radical polymerizable monomer (b-1) other than methyl methacrylate may be used alone or in combination of two or more.

The radical polymerizable monomer (b-1) is methyl methacrylate alone, a combination of methyl methacrylate and another monomer copolymerizable therewith, or a part of a radical polymerizable monomer containing methyl methacrylate. A mixture of the (co) polymer obtained by polymerization of the above and the radical polymerizable monomer is used.
Here, the number average molecular weight of the (co) polymer in which a part of the radical polymerizable monomer is polymerized is not particularly limited, but from the viewpoint of viscosity at the time of injection into the cell, the number average molecular weight is several. The average molecular weight is preferably 300,000 or less. The polymerization rate is preferably 50% by mass or less.
Moreover, the mixing ratio of the (co) polymer in which a part of the radical polymerizable monomer containing methyl methacrylate is polymerized and the radical polymerizable monomer is from 2:98 to 50:50 in mass ratio. Is preferred.
Radical polymerizable monomer (b-1) mainly composed of methyl methacrylate, or a (co) polymer obtained by polymerizing a part of the radical polymerizable monomer (b-1) and the radical polymerizable monomer The usage-amount of a mixture with a body (b-1) is 70-96 mass parts in polymeric mixture (P). If it is 70 parts by mass or more, the transparency of the methacrylic resin laminate is improved, and if it is 96 parts by mass or less, impact resistance is improved.

・ Multi-stage copolymer (b-2)
In the present invention, the multistage polymerization copolymer (b-2) includes a rubbery copolymer having a crosslinked structure obtained by at least one stage polymerization.
In the multistage polymerization copolymer (b-2) in the present invention, the radically polymerizable monomer (b-1) and the rubbery copolymer in the multistage polymerization copolymer (b-2) Since the radical polymerizable monomer (A) can be easily impregnated, it is presumed that the impact resistance of the methacrylic resin molded article is improved. Therefore, the usage-amount of a multistage polymerization copolymer (B) can be decreased, the increase in the viscosity of polymeric mixture (P) is suppressed, and dispersion time is shortened and productivity improves.
Preferable examples of the rubbery copolymer include generally used diene rubbers, acrylic rubbers, silicone rubbers, and silicone / acrylic composite rubbers. Of these, acrylic rubber is preferred from the viewpoint of weather resistance and transparency.

(Acrylic rubber)
Suitable acrylic rubbers include, for example, acrylate ester polymers having 4 to 10 carbon atoms in the alkyl group such as butyl acrylate and 2-ethylhexyl acrylate, and the acrylate ester polymers and the acrylate esters. Examples thereof include a copolymer of a monomer that can be copolymerized with a polymer.
Examples of the copolymerizable monomer include styrene monomers such as styrene and α-methylstyrene; methacrylic acid esters such as methyl methacrylate and ethyl methacrylate; and alkyl groups such as methyl acrylate and ethyl acrylate having 1 carbon atom. Acrylic acid ester having ˜8 and different from the acrylic acid ester having 4-10 carbon atoms in the alkyl group; vinylcyan compound such as (meth) acrylonitrile; ethylene glycol di (meth) acrylate, allyl (meth) acrylate, Examples thereof include polyfunctional polymerizable compounds having two or more ethylenically unsaturated bonds in the molecule such as divinylbenzene and 1,3-butylene di (meth) acrylate. Especially, the said polyfunctional polymerizable compound which can form a crosslinked structure is more preferable.
As the copolymerizable monomer, one kind may be used alone, or two or more kinds may be used in combination, and it is particularly preferable that at least one kind of the polyfunctional polymerizable compound is contained.
The amount of the polyfunctional polymerizable compound used is preferably 5 parts by mass or less, more preferably 0.01 to 3 parts by mass in 100 parts by mass of the rubbery copolymer. If it is 5 parts by mass or less, an appropriate crosslinking density is obtained in the rubber-like copolymer, and impact resistance is improved.

In addition, from the viewpoint of transparency of the obtained methacrylic resin laminate, the refractive index of each stage of the multistage polymerization copolymer (b-2) including a rubbery copolymer having a crosslinked structure obtained by at least one stage of polymerization. A radically polymerizable monomer (b-1) containing methyl methacrylate as a main component, or a (co) polymer obtained by polymerizing a part of the radically polymerizable monomer (b-1) and the radically polymerizable property. It is preferable to adjust so that it may become close to the refractive index of a mixture with a monomer (b-1).
For example, methyl methacrylate alone is used as the radical polymerizable monomer (b-1), and 100 parts by mass of the rubbery copolymer is used as the rubbery copolymer contained in the multistage polymerization copolymer (b-2). Among them, in the methacrylic resin laminate (thickness of about 3 mm) using 80 to 85 parts by mass of butyl acrylate and 20 to 15 parts by mass of styrene, the total light transmittance is 90% or more and the cloud value is 10 or less. Thus, a methacrylic resin laminate having good transparency can be obtained.
Thus, it is preferable to select the carbon number of the alkyl group and the copolymerizable monomer in consideration of the transparency of the methacrylic resin laminate.

  The acrylic rubber may have a multistage structure obtained by polymerization of two or more stages. Moreover, the polyalkyl (meth) acrylate type | system | group composite rubber | gum which contains 2 or more types of monomer units (copolymer) and has two or more glass transition temperatures may be sufficient.

The polymerization method and polymerization conditions for polymerizing the acrylic rubber are not particularly limited, and usual emulsion polymerization, soap-free emulsion polymerization, and the like can be used.
The polymerization initiator for polymerizing the acrylic rubber is not particularly limited, and water-soluble persulfuric acid such as potassium persulfate, sodium persulfate, ammonium persulfate; diisopropylbenzene hydroperoxide, p-menthane hydroper Redox polymerization initiators containing organic peroxides such as oxides, cumane hydroperoxides, t-butyl hydroperoxides, etc., or combinations of the above organic peroxides with one or more reducing agents, etc. Can be used.
When polymerizing acrylic rubber, the emulsifier used is not particularly limited, and alkali metal salts of higher fatty acids such as disproportionated rosin acid, oleic acid and stearic acid; sulfonic acids such as dodecylbenzene sulfonic acid One or more alkali metal salts and the like can be added.
Further, the particle diameter of the acrylic rubber particles dispersed in the rubber latex can be controlled by using a method in which the rubber latex obtained by polymerization is enlarged using an acid or a salt.

In the present invention, the multi-stage copolymer (b-2) latex is, for example, a rubber-like material composed of at least one selected from the above-mentioned diene rubbers, acrylic rubbers, silicone rubbers, silicone / acrylic composite rubbers, and the like. The copolymer latex can be obtained by adding one or more copolymerizable vinyl monomers and graft polymerization.
The vinyl monomer is not particularly limited as long as it does not contain an epoxy group, a glycidyl group, an isoboronyl group, an allyl group, and a hydroxyl group and can be copolymerized with a rubbery copolymer. Specific examples include alkyl methacrylates such as methyl methacrylate and ethyl methacrylate; alkyl esters of acrylic acid such as ethyl acrylate and n-butyl acrylate; aromatic vinyl such as styrene, α-methyl styrene and various halogen-substituted and alkyl-substituted styrenes. An unsaturated nitrile such as acrylonitrile or methacrylonitrile;
These vinyl monomers can also be used as a monomer mixture with a chain transfer agent or the like. The monomer mixture can be used for multistage graft polymerization having one or two or more polymerization steps as necessary from the viewpoint of the balance between dispersibility and impact strength.
In addition, when the vinyl monomer containing any one of an epoxy group, a glycidyl group, an isobornyl group, an allyl group and a hydroxyl group is used, the dispersibility in latex of the obtained multistage polymerization copolymer (b-2) Is unfavorable because it decreases.
The amount of the vinyl monomer used for graft polymerization of the multistage polymer (b-2) is preferably 10 to 70 parts by mass in 100 parts by mass of the multistage polymer (b-2). When it is 70 parts by mass or less, the time required for dispersion is sufficiently shortened, and when it is 10 parts by mass or more, sufficient impact resistance is obtained.

In addition, suitable antioxidant, an additive, etc. can be previously added to multistage polymerization copolymer (b-2) latex as needed.
Moreover, the collection | recovery method of a multistage polymerization copolymer (b-2) is not specifically limited, It can collect | recover by methods, such as well-known spray drying, acid coagulation, and salt coagulation.

  The usage-amount of a multistage polymerization copolymer (b-2) is 4-30 mass parts in a polymeric mixture (P). If it is 30 parts by mass or less, the transparency of the resulting methacrylic resin laminate is improved, and if it is 4 parts by mass or more, impact resistance is improved.

Chain transfer agent When preparing the polymerizable mixture (P), a chain transfer agent may be added for the purpose of adjusting the average molecular weight.
The chain transfer agent can be selected from those usually used for radical polymerization, and preferably a mercaptan chain transfer agent such as an alkyl mercaptan having 2 to 20 carbon atoms, a mercapto acid, thiophenol or a mixture thereof. It is. More preferred is a mercaptan having a short chain length of an alkyl group such as n-octyl mercaptan or n-dodecyl mercaptan.

As a method for producing a methacrylic resin laminate of the present invention, a method of forming a hard coat film (A) in advance using the curable composition (a-1) and the polymerizable mixture (P). For example, a curable composition (a-1) is applied onto a mold (hereinafter sometimes referred to as “mold or the like”) made of a mold or a substrate (S), and the curable composition (a -1) is cured to form a hard coat film (A), and the hard coat film (A) is an inner surface (herein, the inner surface refers to a cell space side surface). A cell production step of producing a cell for casting polymerization using a mold or the like on which the hard coat film (A) is formed, and casting by injecting the polymerizable mixture (P) into the cell After the polymerization process for carrying out the polymerization and after the casting polymerization, from the cell, the hard coat Production method and a step of taking out the laminate comprising film (A) and the resin substrate layer and (B) may be mentioned as a preferred example.
Hereinafter, the curing step, the cell preparation step, the polymerization step, and the step of taking out the laminate will be described.

<Curing process>
In the curing step, the curable composition (a-1) is applied onto a mold composed of a mold and a substrate (S), and the curable composition (a-1) is cured to form a hard coat film (A). Form.
The hard coat film (A) is disposed on one side or both sides in the methacrylic resin laminate manufactured by the manufacturing method of the present invention, and mainly exhibits an effect of scratch resistance.
In particular, when it is disposed on only one surface, the hard coat film (A) surface is preferably used as the front surface (surface that receives impact and friction) of the methacrylic resin laminate.

The mold comprising the mold and the substrate (S) preferably has a smooth surface. Thereby, a methacrylic resin laminate having a high surface smoothness can be produced. Specifically, a sheet-like thing, an endless belt, etc. are mentioned.
As the material of the mold, stainless steel is particularly preferable.
The material of the mold made of the base material (S) is not particularly limited, and stainless steel and glass plate are particularly preferable.
The mold made of the substrate (S) may be the same as the mold.

  Examples of the coating method of the curable composition (a-1) include a film cover method, a casting method, a roller coating method, a bar coating method, a spray coating method, and an air knife coating method. Especially, it is a method of forming a hard coat film (A) in advance, the surface of the methacrylic resin laminate to be produced has high surface smoothness, and the hard coat film (A) and the resin base material layer (B). The film cover method and the air knife coating method are preferable because of good adhesion to the film.

(Film cover method)
In the film cover method, for example, a coating film of the curable composition (a-1) is formed on the mold by a coating process in which the curable composition (a-1) is interposed between the mold and the resin film. Then, a resin film is placed on the coating film. Next, the curable composition (a-1) on the mold is irradiated with an active energy ray through the resin film, whereby the curable composition (a-1) is cured and a hard coat film ( A) is formed. Thereafter, in the next cell production step, the resin film is peeled off to produce a cell for cast polymerization.
As the resin film, a polyethylene terephthalate (PET) film, a polypropylene (PP) film, a polyethylene (PE) film, a polyvinylidene fluoride (PVDF) film, etc. can be used, but the cost and the hard coating film are hardened by PET. A film is preferred.
The thickness of the resin film is preferably 8 to 125 μm.
After the resin film is covered on the coating film, the resin film surface can be smoothed with a rubber roll having a JIS hardness of 40 °. Thereby, a coating film having a uniform film thickness can be formed, and a coating film having high smoothness and a desired film thickness can be obtained.
The active energy ray to be irradiated is preferably a fluorescent ultraviolet lamp or a high-pressure mercury lamp, and more preferably a fluorescent ultraviolet lamp from the viewpoint of the curing rate of the curable composition (a-1). As conditions for irradiation with active energy rays, it is preferable to select the type of light source, the distance between the light source and the resin film surface, and the irradiation time so as to be 300 to 1000 mW / cm ² .

In addition, by irradiating an active energy ray through the said resin film, bridge | crosslinking polymerization will fully advance, the target sclerosis | hardenability will become easy to be obtained, and scratch resistance will improve. Further, the smoothness of the surface of the hard coat film (A) (the surface on the resin film side) is increased, and further, there is no possibility that foreign matters are mixed during curing.
In addition, after the hard coat film (A) is formed, the hard coat film (A) can be further cured by irradiation with active energy rays. Thereby, sclerosis | hardenability can be improved more. In that case, the active energy ray to be irradiated is preferably a high-pressure mercury lamp. The output and irradiation conditions at that time are the same as described above.

(Air knife coating method)
Next, the air knife coating method will be described with reference to FIG.
FIG. 1 is a schematic diagram showing an example of an apparatus for air knife coating.
In the apparatus shown in FIG. 1, the sheet-like material 1 is a metal sheet on which a hard coat film (A) is formed, and preferably 0.5 to 30 m / min. Drive at the speed of
The spray nozzle pipe 2 is a supply unit that supplies the coating liquid of the curable composition (a-1) to the surface of the sheet-like material 1.
The air nozzle 3 is a slit type air nozzle having a slit clearance of 0.05 to 5 mm. By spraying on the curable composition (a-1) dropped on the surface of the sheet-like material 1, a coating film having a uniform film thickness can be formed.
The mounting position of the air nozzle 3 is parallel to the width direction of the sheet-like object 1, the height from the sheet-like object 1 is 0.5 to 100 mm, and the angle is perpendicular to the vertical downward direction of the surface of the sheet-like object 1. The sheet-like object 1 is disposed so as to be inclined by 0 to 45 ° toward the traveling direction side.

In the air knife coating method, for example, the curable composition (a-1) is dropped onto the surface of the sheet-like material 1 from the spray nozzle pipe 2, and then the air nozzle 3 under which air is blown out with a constant air volume. Can be formed at a predetermined speed to form a coating film of the curable composition (a-1) on the sheet-like material 1.
In that case, it is preferable to make the coating temperature 5-60 degreeC using the said coating liquid whose viscosity in 25 degreeC becomes like this. Preferably it is 10-1000 mPa * s.
Next, the curable composition (a-1) on the sheet-like material 1 is irradiated with active energy rays to cure the curable composition (a-1) to form a hard coat film (A). To do.
The active energy ray to be irradiated is preferably a fluorescent ultraviolet lamp or a high-pressure mercury lamp, and more preferably a high-pressure mercury lamp from the viewpoint of the curing rate of the curable composition (a-1).
As conditions for irradiation with active energy rays, it is preferable to select the type of light source, the distance between the light source and the resin film surface, and the irradiation time so as to be 300 to 1000 mW / cm ² .
In addition, the air knife coating method can reduce the cost of the resin film as compared with the film cover method, and can form a wide hard coat film (A) without being restricted by the width of the mold. .

In the curing step, the hard coating film (A) is formed by curing the curable composition (a-1) on the mold composed of the mold and the substrate (S) by the above-described various coating methods.
The thickness of the hard coat film (A) to be formed is preferably 10 to 30 μm. When it is 10 μm or more, the scratch resistance is good, and when it is 30 μm or less, cracks and the like at the time of cutting of the methacrylic resin laminate are less likely to occur, and the workability is good.

<Cell manufacturing process>
In the cell production step, a cell for cast polymerization is produced so that the hard coat film (A) obtained in the previous step becomes the inner surface.
As a method for producing the cell, for example, a mold on which the hard coat film (A) is formed is arranged so that the hard coat film (A) becomes an inner surface, and the base material (S) is opposed to the mold. And a method of producing a cell having a constant volume on the inside by providing a gasket on the peripheral portion of the mold and the base material (S) and sealing them.
Here, the substrate (S) may be the same as described above, and preferably has the same shape as the mold on which the hard coat film (A) is formed, from the viewpoint of airtightness of the cell.
Moreover, the hard-coat film (A) may be formed in the said base material (S), and it does not need to be formed. In the former case, a methacrylic resin laminate having a hard coat film (A) on both sides of the resin base layer (B) and in the latter case on one side of the resin base layer (B) is obtained.
The material of the gasket is preferably polyvinyl chloride, and more preferably soft polyvinyl chloride.

<Polymerization process>
In the polymerization step, cast polymerization is performed by injecting the polymerizable mixture (P) into the cell prepared in the previous step. In that case, in the cell, the said polymeric mixture (P) hardens | cures by a polymerization reaction, and a resin base material layer (B) is formed.
This resin base material layer (B) is transferred from the inside of the cell to the hard coat film (A), and the hard coat film (A) and the resin base material layer (B) are integrally formed. The resin base layer (B) has a hard coat film (A) disposed on one side or both sides thereof, and mainly exhibits an impact resistance effect.
In the present invention, “cast polymerization” means general polymerization performed by injecting a polymerizable compound, a polymerization initiator, or the like into a space having a certain volume, such as the cell. Preferably, casting polymerization performed using a mold is shown.
In the present invention, by using this cast polymerization, the polymerizable mixture (P) can be polymerized without any limitation in molecular weight, and the resin base layer (B) obtained by curing has high mechanical strength. Obtainable. In addition, since the adhesion between the resin base layer (B) and the hard coat film (A) is increased and can be integrally formed without unevenness, the produced methacrylic resin laminate has impact resistance and scratch resistance. And at the same time.

  The method for polymerizing and curing the polymerizable mixture (P) is not particularly limited, and among these, it is preferable to use a radical polymerization initiator.

-Radical polymerization initiator Examples of the radical polymerization initiator include 2,2'-azobisisobutyronitrile, 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2 , 4-dimethyl-4-methoxyvaleronitrile), etc .; organic peroxides such as benzoyl peroxide, lauroyl peroxide, t-hexyl peroxypivalate; etc .; by combination of the organic peroxide and amines Examples thereof include redox polymerization initiators.
These radical polymerization initiators may be used alone or in combination of two or more.
It is preferable that the usage-amount of a radical polymerization initiator shall be 0.005-5 mass parts with respect to 100 mass parts of polymeric mixtures (P).

(Cast polymerization)
In the present invention, it is preferable to cure the polymerizable mixture (P) (preferably from which dissolved air has been removed by reduced pressure or the like) by a polymerization reaction in the cell by cast polymerization.
As a method for cast polymerization, a so-called cell casting method in which the polymerizable mixture (P) is poured into a cell and heated is a preferable method.
As the heating method, for example, the cell can be heated and heated with 30 to 98 ° C. warm water to be cured.
Thereafter, in order to further improve the curability, heat treatment at 90 to 150 ° C. can be performed with a far infrared heater or the like in an air atmosphere. And it cools by ventilation etc. as needed.
The material of the gasket is the same as that of the gasket.
Two polymerizable endless belts facing each other running at the same speed in the same direction, and the polymerizable mixture continuously from upstream in a space where both end portions of the stainless steel endless belt are sealed with gaskets. A method of continuously polymerizing by pouring (P) and heating (a continuous casting method described later) and the like can also be mentioned as a suitable method.

As thickness of the resin base material layer (B) formed, it is preferable that it is 0.2-300 mm. If it is 0.2 mm or more, impact resistance is good, and if it is 300 mm or less, cracks and the like during cutting of the methacrylic resin laminate are less likely to occur, and workability is good.
Moreover, in this invention, it is preferable that the acetone insoluble amount of the resin base material layer (B) is 1.3 times or more of the acetone insoluble amount of the multistage polymerization copolymer (b-2). By setting it to 1.3 times or more, the polymerizable mixture (P) is sufficiently polymerized, and a methacrylic resin laminate having good impact resistance is obtained. As a method for setting the amount of insoluble acetone in the resin base layer (B) to 1.3 times or more of the amount of insoluble acetone in the multistage polymer (b-2), a multistage polymer (b- 2) Control of crosslinking density, that is, adjustment of the amount of crosslinking agent added.

<Step of taking out the laminate>
In the step of taking out the laminate, after completion of the casting polymerization in the polymerization step, the laminate having the hard coat film (A) and the resin base material layer (B) is peeled from the cell and taken out. -Based resin laminate is manufactured.

In addition, in this invention, manufacture of a methacrylic-type resin laminated product can also be performed continuously. As a suitable method, for example, a so-called continuous casting method can be mentioned. Productivity is particularly improved by using the continuous casting method.
An example of the continuous casting method will be specifically described with reference to FIGS.

FIG. 2 is a sectional view showing an apparatus using a pair of endless belts, and FIG. 3 is a schematic view showing a lower endless belt surface in FIG.
The endless belts 11a and 11b travel in the direction of the arrow facing each other with a predetermined interval.
Further, the gaskets 12a and 12b travel on both side ends of the endless belts 11a and 11b following the endless belts 11a and 11b. The endless belts 11a and 11b and the gaskets 12a and 12b form a space for performing casting polymerization.
The material of the endless belts 11a and 11b is the same as that of the mold, and stainless steel is particularly preferable. The endless belts 11a and 11b preferably have a thickness of about 0.5 to 5 mm.
The material of the gaskets 12a and 12b is the same as that of the gasket.

In FIG. 3, a hard coat film 21 in which the curable composition (a-1) is cured is formed in advance on the surface of the endless belt 11a.
The hard coat film 21 can be formed on one or both surfaces of the endless belts 11a and 11b on the opposite surface side by using the same method as in the curing step.
The hard coat film 21 supplies the curable composition (a-1) from the curable composition coating nozzle 22 onto the endless belts 11a and 11b while running the endless belts 11a and 11b. It forms by irradiating an active energy ray by etc. and superposing | polymerizing and hardening a curable composition (a-1). In that case, as a coating method of curable composition (a-1), the said air knife coating method etc. can be used.

Next, while running the endless belts 11a and 11b, the polymerizable mixture (P) is continuously injected from the polymerizable mixture supply nozzle 23 onto the surface of the hard coat film 21 in the space portion, and cast polymerization is performed. A resin base material layer (B) is formed.
For injecting the polymerizable mixture (P) into the space portion, a metering pump or the like can be used to continuously inject a constant amount from one end of the space portion (polymerizable mixture supply nozzle 23).
The casting polymerization can be cured by heating the endless belts 11a and 11b while heating with a hot water shower at 30 to 98 ° C. or the like.
Thereafter, in order to further improve the curability, heat treatment at 90 to 150 ° C. can be performed by a far infrared heater or the like.
And it cools to 30-120 degreeC by ventilation etc.
After cooling, the laminate having the hard coat film 21 and the resin base material layer (B) is peeled off from the endless belts 11a and 11b and continuously taken out to obtain a methacrylic resin laminate.

In addition, in the methacrylic resin laminated product to be manufactured, if necessary, antireflection between the surface of the hard coat film (A) or between the hard coat film (A) and the resin base material layer (B). It is also possible to form a film or an antistatic layer.
Furthermore, in the production method of the present invention, a release agent, a colorant, an ultraviolet absorber, a heat stabilizer, an antistatic agent, a filler and the like can be appropriately added in any convenient step.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples. Note that “parts” represents mass parts and “%” represents mass%. Each measurement method and evaluation method in this example are shown below.

(1) Measurement of particle diameter of polymer in latex The obtained latex was diluted with distilled water, and 50% number was obtained using a laser diffraction scattering type particle size distribution measuring device (LA-910, manufactured by Horiba, Ltd.). The average particle size was measured.

(2) Measurement of acetone insoluble fraction of components constituting multistage copolymer and resin base material layer (B) About 0.5 g of sample and 50 cc of acetone were added to a 200 ml eggplant type flask. It was set in a condenser and refluxed at a temperature of 65 ° C. for 4 hours. The sample solution after cooling was added to a centrifugal sedimentation tube (cell) and separated by a centrifuge to collect a sample insoluble in acetone. The setting conditions of the centrifuge were as follows: rotation speed: 14000 rpm, time: 30 minutes, and ambient temperature: 4 ° C.
Next, the sample collected in the centrifugal sedimentation tube (cell) is heated by a water bath in the centrifugal sedimentation tube (cell) to evaporate acetone contained in the sample. Was dried. Thereafter, the weight of the centrifugal sedimentation tube (cell) is measured, and the acetone insoluble amount (g) is obtained by subtracting the weight of the centrifugal sedimentation tube (cell) that has been measured in advance, from the following formula (I) The acetone insoluble fraction (gel content, mass%) was determined.
Acetone insoluble fraction (gel content, mass%) = acetone insoluble amount (g) / sample weight before dissolution (g) × 100

(3) Evaluation of transparency The transparency was evaluated by measuring the total light transmittance and the haze value using a haze meter (manufactured by Color Research Laboratory, HR-100) in an atmosphere at 23 ° C.

(4) Evaluation of scratch resistance The scratch resistance was evaluated by the change in haze (scratch haze) before and after the scratch test. In other words, a circular pad with a diameter of 25.4 mm equipped with # 000 steel wool was placed on the surface of the coating film (hard coat film) side of the sample, and under a load of 9.8 N, a 20 mm distance was scratched 100 times. Then, the difference in haze value before and after scratching was determined from the following formula (II), and scratch resistance was evaluated based on the following criteria.
[Abrasion Haze (%)] = [Haze After Abrasion (%)] − [Haze Before Abrasion (%)] (II)
○: The value of scratch haze (%) is less than 0.2 (%).
X: The value of scratch haze (%) is 0.2 (%) or more.

(5) Evaluation of impact resistance According to JIS K 7211, the impact resistance was evaluated by calculating 50% fracture energy (J) in a Dupont falling weight test and measuring the surface impact strength. In addition, it measured so that a hard-coat surface might turn into a striking surface.

(Production Example 1)
Production of multi-stage polymerization copolymer (b-2-1):
116 mass parts of pure water was put into a 5 L flask equipped with a stirring rod and a cooling tube, and heated to 80 ° C. while stirring at a rotation speed of 150 rpm in a nitrogen atmosphere. Dissolved by dissolving 0.000075 parts by mass of disodium ethylenediaminetetraacetic acid, 0.000025 parts by mass of ferrous sulfate and 0.25 parts by mass of sodium formaldehyde sulfoxylate in 1.9 parts by mass of pure water. The liquid was added. Next, 13.94 parts by mass of methyl methacrylate, 9.99 parts by mass of n-butyl acrylate, 1.06 parts by mass of styrene, 0.75 parts by mass of 1,3-butylene dimethacrylate, 0.094 parts by mass of allyl methacrylate, t- 0.044 parts by mass of butyl hydroperoxide, polyoxyethylene alkyl ether phosphate ester salt (trade name: RS-610NA, manufactured by Toho Chemical Co., Ltd., hereinafter referred to as “RS-610NA”) 0.95 parts by mass 1/10 of the mixed solution was added dropwise over 4 minutes and held for 15 minutes, and then the remaining mixed solution 9/10 was added dropwise over 108 minutes and held for 40 minutes. went.
Subsequently, a solution obtained by dissolving 0.125 parts by mass of sodium formaldehyde sulfoxylate in 1.91 parts by mass of pure water was added all at once, and after maintaining for 15 minutes, 30.939 parts by mass of n-butyl acrylate and 6.563 parts by mass of styrene. Parts, 1,3-butylene dimethacrylate 0.094 parts by mass, allyl methacrylate 0.656 parts by mass, cumene hydroperoxide 0.106 parts by mass, RS-610NA 0.6 parts by mass is dropped over 180 minutes. , Held for 105 minutes to conduct the second stage polymerization.
Subsequently, a solution obtained by dissolving 0.125 parts by mass of sodium formaldehyde sulfoxylate in 1.91 parts by mass of pure water was added all at once, and after maintaining for 15 minutes, 35.63 parts by mass of methyl methacrylate and 1.88 parts by mass of methyl acrylate , T-butyl hydroperoxide 0.064 parts by mass and n-octyl mercaptan 0.113 parts by mass is added dropwise over 120 minutes, held for 60 minutes, the third stage polymerization is performed, multistage polymerization A copolymer (b-2-1) latex was obtained. The number average particle diameter of the multistage polymerization copolymer (b-2-1) in the latex was 280 nm.
The obtained multistage polymerization copolymer (b-2-1) latex was sprayed with fine droplets using an atomizer with a rotational speed of 25000 rpm using a spray dryer, and dried at a hot air inlet temperature of 150 ° C. A multistage polymerization copolymer (b-2-1) was obtained. The acetone insoluble fraction was 90.0% by mass.

(Production Example 2)
Production of multistage polymerization copolymer (b-2-2):
In a 5 L flask equipped with a stirrer and a condenser, 100 parts by mass of pure water, 0.008 parts by mass of sodium dialkylsulfosuccinate (trade name: Perex OT-P, manufactured by Kao Corporation), 2.788 parts by mass of methyl methacrylate Part, n-butyl acrylate 2 parts by mass, styrene 0.212 parts by mass, allyl methacrylate 0.0188 parts by mass, 1,3-butylene dimethacrylate 0.15 parts by mass to perform nitrogen substitution, rotation in a nitrogen atmosphere The mixture was heated to 80 ° C. with stirring at several 150 rpm. A solution obtained by dissolving 0.05 part by mass of potassium persulfate in 5 parts by mass of pure water was added all at once, and held for 60 minutes to carry out the first stage polymerization.
Subsequently, a solution obtained by dissolving 0.1 part by mass of potassium persulfate in 5 parts by mass of pure water was added all at once, and 40 parts by mass of pure water, 47.44 parts by mass of n-butyl acrylate, 10.06 parts by mass of styrene, , 3-butylene dimethacrylate 0.144 parts by weight, allyl methacrylate 0.575 parts by weight, dialkyl sulfosuccinate 0.36 parts by weight of nitrogen-substituted mixture was added dropwise over 280 minutes, then held for 120 minutes, Second stage polymerization was carried out.
Then, 35.625 parts by mass of methyl methacrylate, 1.875 parts by mass of methyl acrylate, and 0.113 parts by mass of n-octyl mercaptan were added dropwise over 120 minutes, and then maintained for 120 minutes to maintain the third stage. Polymerization of the eyes was performed to obtain a multistage polymerization copolymer (b-2-2) latex. The number average particle diameter of the multistage polymerization copolymer (b-2-2) in the latex was 417 nm.
The obtained multistage polymerization copolymer (b-2-2) latex was sprayed with fine droplets using an atomizer with a rotational speed of 25000 rpm using a spray dryer, and dried at a hot air inlet temperature of 150 ° C. A multistage polymerization copolymer (b-2-2) was obtained. The acetone insoluble fraction was 76.2% by mass.

Example 1
-Preparation of curable composition (a-1) As polymerizable compound (a-1-1), 3 mol of 3-acryloyloxy-2-hydroxy per 1 mol of triisocyanate composed of trimer of hexamethylene diisocyanate Urethane compound obtained by reacting propyl methacrylate (trade name: NK ester U-6HA, manufactured by Shin-Nakamura Chemical Co., Ltd., hereinafter referred to as “U6HA”) 30 parts by mass, 1,6-hexanediol diacrylate (Osaka Organic Chemical Industry Co., Ltd., hereinafter referred to as “C6DA”) 60 parts by mass and pentaerythritol triacrylate (manufactured by Toagosei Co., Ltd., hereinafter referred to as “M305”) 10 parts by mass were used. .
Further, 1.5 parts by mass of benzoin ethyl ether (trade name: BEE, manufactured by Seiko Chemical Co., Ltd., hereinafter referred to as “BEE”) was used as the photopolymerization initiator (a-1-2).
And the (a-1-1) component and the (a-1-2) component were mixed and dissolved, and the curable composition (a-1) was prepared.

Partially polymerized methyl methacrylate (viscosity 1000 mPa · s, polymerization rate 20% by mass) 33.136 parts by mass, methyl methacrylate 54.064 parts by mass and n-dodecyl mercaptan 0.06 parts by mass were added and stirred at 500 rpm. While adding 12.8 parts by mass (the acetone insoluble fraction 11.52% by mass) of the multistage polymerization copolymer (b-2-1) obtained in Production Example 1 described above, the mixture was stirred for 2 hours to polymerize. A sex mixture (P1) was prepared.
Next, 0.32 parts by mass of t-hexylperoxypivalate was added to the polymerizable mixture (P1), and the mixture was stirred for 5 minutes to obtain a mixed syrup (S1) having a viscosity of 3000 mPa · s.

-Production of methacrylic resin laminate A SUS304 plate having a mirror surface was used as a mold.
The curable composition (a-1) is applied onto a mirror surface of a SUS304 plate, and a PET film having a thickness of 12 μm is placed on the coated surface, and the curable composition (a−) is interposed between the SUS304 plate and the PET film. 1) was interposed. At that time, using a rubber roll having a JIS hardness of 40 °, the PET film was pressure-bonded so as not to contain bubbles while squeezing out the excessive curable composition (a-1). The film thickness of the curable composition (a-1) at this time was 22 μm.
Next, with the PET film surface facing up, a fluorescent ultraviolet lamp (Toshiba Corp.) having an output of 40 W from a position 20 cm in height from the PET film surface through the PET film to the curable composition (a-1). Made by FL40BL), the curable composition (a-1) was cured to form a hard coat film (A1). At that time, the coating film of the curable composition (a-1) was passed under the fluorescent ultraviolet lamp at a speed of 0.3 m / min.
And PET film was peeled leaving the hard-coat film (A1) on the SUS304 board. Next, with the hard coat film (A1) side up, the hard coat film (A1) is irradiated with a high pressure mercury lamp with an output of 30 W from a position 20 cm in height from the hard coat film (A1) surface. The coating (A1) was further cured to obtain a cured film having a thickness of 20 μm. At that time, the hard coat film (A1) was passed under the high-pressure mercury lamp at a speed of 0.3 m / min to perform further curing.
Next, the SUS304 plate on which the cured film is formed and the SUS304 plate on which the cured film is not formed are opposed to each other so that the cured film becomes the inner surface, and the peripheral portion of these SUS304 plates is formed with a soft polyvinyl chloride gasket. A cell for sealing and casting polymerization was prepared.
The above-mentioned mixed syrup (S1) from which dissolved air was removed by decompression was injected into this cell, polymerized in a 78 ° C. water bath for 45 minutes, and then polymerized in a 130 ° C. air furnace for 45 minutes.
After cooling, the SUS304 plate was peeled from the cell to obtain an acrylic resin laminate having a thickness of 3 mm and having a hard coat film (A1) on one surface of the resin base material layer (B1).
The obtained acrylic resin laminate had a scratch haze of 0.07% and a 50% fracture energy of 3.0J.

(Example 2)
-Preparation of curable composition (a-2) The thing similar to the curable composition (a-1) used in Example 1 was used.

34.2 parts by weight of a partially polymerized methyl methacrylate (viscosity 1000 mPa · s, polymerization rate 20% by weight), 55.8 parts by weight of methyl methacrylate and 0.06 parts by weight of n-dodecyl mercaptan were added and stirred at 500 rpm. While adding 10 parts by mass of the multi-stage polymerization copolymer (b-2-2) obtained in Production Example 2 (acetone insoluble fraction: 7.62% by mass), the mixture was stirred for 40 minutes to obtain a polymerizable mixture. (P2) was prepared.
Next, 0.32 parts by mass of t-hexylperoxypivalate was added to the polymerizable mixture (P2), and the mixture was stirred for 5 minutes to obtain a mixed syrup (S2) having a viscosity of 3000 mPa · s.

-Manufacture of a methacrylic-type resin laminated product The cell for cast polymerization was produced like Example 1 using the said curable composition (a-2).
The above-mentioned mixed syrup (S2) from which dissolved air was removed by decompression was injected into this cell, polymerized in a 78 ° C. water bath for 45 minutes, and then polymerized in a 130 ° C. air furnace for 45 minutes.
After cooling, the SUS304 plate was peeled from the cell to obtain an acrylic resin laminate having a thickness of 3 mm and having a hard coat film (A2) on one surface of the resin base material layer (B2).
The obtained acrylic resin laminate had a scratch haze of 0.07% and a 50% fracture energy of 3.1J, which was good.

(Example 3)
-Preparation of curable composition (a-3) The thing similar to the curable composition (a-1) used in Example 1 was used.

-Manufacture of methacrylic resin laminates The traveling of a pair of SUS304 endless belts having a mirror finish of 2800 mm in width and 1 mm in thickness that run oppositely at the same speed in the same direction is temporarily stopped. A hard coat film (A3) was formed on the upper endless belt surface in the same manner as in Example 1. Thereafter, the hard coat film (A3) is irradiated with a 120 W high-pressure mercury lamp from a position 17 cm in height from the surface of the hard coat film (A3), and the hard coat film (A3) is further cured to form a cured film. Obtained. At that time, the hard coat film (A3) was passed under the high-pressure mercury lamp at a speed of 2.5 m / min, and further curing was performed. The cured state at this time was good, and the entire surface was solidified and there was no liquid product.
Next, the endless belt on which the hard coat film (A3) is formed, and each of the endless belts are respectively surrounded by a soft polyvinyl chloride gasket that travels at the same speed following the both end portions of the endless belt. The above-described mixed syrup (S1) was continuously injected at a constant flow rate using a metering pump into a mold (space part) set so that the gap between the belts was 3.8 mm in advance, and cast polymerization was performed. . At that time, along with the running of the endless belt, polymerization was carried out by heating for 45 minutes in a hot water shower at 78 ° C. and cured. Thereafter, heat treatment at 135 ° C. was further performed for 30 minutes with a far infrared heater, and then cooled to 85 ° C. over 10 minutes by air blowing.
After cooling, the laminate (acrylic resin laminate) having the hard coat film (A3) on one surface of the resin base material layer (B3) was continuously peeled from the endless belt and taken out.
The obtained acrylic resin laminate was colorless and transparent without becoming cloudy, the scratch haze was 0.09%, and the 50% fracture energy was as good as 2.9J.

Example 4
-Preparation of curable composition (a-4) As a polymeric compound (a-1-1), 30 mass parts of U6HA, 60 mass parts of C6DA, and 10 mass parts of M305 were used.
Further, as the photopolymerization initiator (a-1-2), 2-hydroxy-2-methyl-1-phenyl-propan-1-one (trade name: DAROCUR 1173, manufactured by Ciba Specialty Chemicals Co., Ltd.) 4 parts by mass and 2 parts by mass of BEE were used in combination.
And the (a-1-1) component and the (a-1-2) component were mixed and dissolved, and the curable composition (a-4) was prepared.

-Manufacture of methacrylic resin laminate product Using the apparatus shown in FIG. 1, the curable composition (a-4) is dropped onto a SUS304 plate by an air knife coating method to form a coating film having a thickness of 15 μm. did.
The setting conditions performed at that time are shown below.
The spray nozzle pipes 2 were arranged so that the height of the spray nozzle pipe 2 was 150 mm from the sheet-like object 1 and four lines were arranged in a row at 115 mm intervals in the width direction of the sheet-like object 1.
The supply of the curable composition (a-4) from the spray nozzle pipe 2 to the surface of the sheet-like material 1 was adjusted so as to have an average droplet diameter of 1 mm.
The air nozzle 3 has a length of 600 mm, a slit clearance of 0.15 mm, and an air flow rate of 1 m ³ / min. The slit type air nozzle was used.
The mounting position of the air nozzle 3 is parallel to the width direction of the sheet-like object 1 and the height from the sheet-like object 1 is 10 mm. The object 1 was arranged so as to be inclined 5 ° toward the traveling direction side.
The coating temperature was set to 25 ° C., and the viscosity of the coating solution at 25 ° C. was 60 mPa · s.

Thereafter, the coating film of the curable composition (a-4) is irradiated with the same high-pressure mercury lamp as in Example 3, and the curable composition (a-4) is cured to obtain a hard coat film (A4). It was. The cured state at this time was good, and the entire surface was solidified and there was no liquid product.
In this way, two SUS304 plates on which the hard coat film (A4) was formed were produced.
Next, the two SUS304 plates on which the hard coat coating (A4) is formed are made to face each other so that the hard coat coating (A4) becomes the inner surface, and the peripheral portions of these SUS304 plates are covered with a soft polyvinyl chloride gasket. A cell for sealing and casting polymerization was prepared.
The above-mentioned mixed syrup (S1) from which dissolved air was removed by decompression was injected into this cell, polymerized in a 78 ° C. water bath for 45 minutes, and then polymerized in a 130 ° C. air furnace for 45 minutes.
After cooling, the SUS304 plate was peeled off from the cell to obtain an acrylic resin laminate having a thickness of 3 mm and having a hard coat film (A4) on both surfaces of the resin base material layer (B4).
The obtained acrylic resin laminate had a scratch haze of 0.08% and a 50% fracture energy of 3.0J, which was good.

(Comparative Example 1)
A methacrylic resin single-layer product was obtained in the same manner as in Example 1 except that no hard coat film was formed.
The resulting methacrylic resin single-layer product had good impact resistance of 3.1 J, but had high scratch haze and poor scratch resistance.

(Comparative Example 2)
Partially polymerized methyl methacrylate (viscosity 1000 mPa · s, polymerization rate 20% by mass) 38.0 parts by mass, methyl methacrylate 62.0 parts by mass and n-dodecyl mercaptan 0.07 parts by mass were added and stirred at a rotation speed of 500 rpm. While stirring for 2 hours, a polymerizable mixture (P3) was prepared.
Next, 0.33 parts by mass of t-hexylperoxypivalate was added to the polymerizable mixture (P3), and the mixture was stirred for 5 minutes to obtain a mixed syrup (S3) having a viscosity of 3000 mPa · s.
A methacrylic resin laminate was obtained in the same manner as in Example 1 except that this mixed syrup (S3) was injected.
The scratch haze of the obtained methacrylic resin laminate was as good as 0.08%, but the 50% fracture energy was 0.7J and the strength was poor.

As shown in Table 1, it was confirmed that the methacrylic resin laminates produced in Examples 1 to 4 had good results with respect to impact resistance, scratch resistance, and transparency.
On the other hand, the methacrylic resin single layer product of Comparative Example 1 showed poor scratch resistance, and the methacrylic resin laminate product of Comparative Example 2 showed inferior impact resistance.

  Since the methacrylic resin laminate obtained by the production method of the present invention is excellent in scratch resistance, impact resistance, transparency and productivity, for example, window glass, signboard, lighting fixture cover, optical component, automobile, etc. It is useful as a resin laminate used in various applications such as related parts, portable face plates, liquid crystal covers, and sound insulation walls.

It is a schematic diagram which shows an example of the air knife coat method. It is sectional drawing which shows the apparatus using a pair of endless belt. It is a schematic diagram which shows the lower endless belt surface in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sheet-like material 2 Spray nozzle pipe 3 Air nozzle 11a Endless belt 11b Endless belt 12a Gasket 12b Gasket 21 Hard coat film | membrane 22 Nozzle for curable composition application | coating 23 Polymerizable mixture supply nozzle 31 Ultraviolet irradiation apparatus

Claims (5)

  The curable composition (a-1) is cured to form a hard coat film (A), and a radical polymerizable monomer (b-) mainly composed of methyl methacrylate is formed on the surface of the hard coat film (A). 1) or 70 to 96 parts by mass of a mixture of a (co) polymer in which a part of the radical polymerizable monomer (b-1) is polymerized and the radical polymerizable monomer (b-1) A resin base material obtained by curing a polymerizable mixture (P) with 30 to 4 parts by mass of a multistage polymerization copolymer (b-2) containing a rubbery copolymer having a crosslinked structure obtained by at least one stage polymerization The manufacturing method of the methacrylic resin laminated product which forms a layer (B). An application step of interposing the curable composition (a-1) between the mold and the resin film;
The hardenable coating (A) is formed by irradiating the curable composition (a-1) on the mold with active energy rays through the resin film and curing the curable composition (a-1). A curing process,
After peeling off the resin film, the mold, the base material (S) facing the mold, the mold and the base material so that the hard coat film (A) formed in the curing step becomes the inner surface A cell production step of producing a cell comprising a gasket provided on the peripheral portion of (S);
A polymerization step in which the polymerizable mixture (P) is injected into the cell to perform cast polymerization;
The method for producing a methacrylic resin laminate according to claim 1, further comprising a step of taking out a laminate having a hard coat film (A) and a resin base material layer (B) from the cell after completion of the casting polymerization. A curing step of forming the hard coat film (A) on the mold and the substrate (S);
A cell comprising the mold, the base material (S) facing the mold, and a gasket provided on the periphery of the mold and the base material (S) so that the hard coat film (A) is on the inner surface. A cell production process for producing
A polymerization step in which the polymerizable mixture (P) is injected into the cell to perform cast polymerization;
A process for removing a laminate having a hard coat film (A) on both surfaces of the resin base material layer (B) from the cell after completion of the casting polymerization. Production method.   The endless in which the hard coat film (A) is formed by curing the curable composition (a-1) on one surface or both surfaces on the opposite surface side of the pair of endless belts, and the hard coat film (A) is formed. The polymerizable mixture (P) is continuously injected into a space surrounded by a belt and each gasket that travels following both end portions of the endless belt to perform cast polymerization, and the endless The method for producing a methacrylic resin laminate according to claim 1, wherein a laminate having the hard coat film (A) and the resin base material layer (B) is continuously taken out from the belt. The acetone insoluble amount of the resin base material layer (B) is 1.3 times or more of the acetone insoluble amount of the multistage polymerization copolymer (b-2). A method for producing a methacrylic resin laminate.

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