JP2019174496A - (meth)acrylic film and use thereof - Google Patents

Abstract

To provide a (meth)acrylic film which suppresses absorption of light in the visible region and enables uniform coating of a water-based primer, and to provide uses thereof.SOLUTION: A (meth)acrylic film is provided, which is made of a thermoplastic resin composition containing a (meth)acrylic resin and an ultraviolet absorber having a molecular weight less than 700, and exhibits a contact angle of 76° or less with pure water.SELECTED DRAWING: None

Description

  More particularly, the present invention relates to a (meth) acrylic film, an optical film using the (meth) acrylic film, and a polarizer protective film using the optical film. The present invention relates to a polarizing plate provided with the polarizer protective film and an image display device provided with the polarizing plate.

  In recent years, (meth) acrylic resins have been used as raw materials for optical films. When an optical film made of a (meth) acrylic resin is exposed to light containing ultraviolet rays, it may turn yellow and the transparency may decrease. As a method for preventing this phenomenon, a method is known in which an ultraviolet absorber (UVA) is added to a (meth) acrylic resin and an optical film is produced from the composition. Examples of UVA include triazine ultraviolet absorbers (Patent Document 1) and benzotriazole compounds (Patent Document 2).

  The (meth) acrylic film obtained by using UVA as described above is coated with a water-based primer such as a hydrophilic easy-to-adhesive agent and the surface is modified, and further processed. become.

International Publication No. 2008/153143 JP 2007-108775 A specification

  However, when a water-based primer is applied to a (meth) acrylic film prepared by adding an ultraviolet absorber having a molecular weight of less than 700, uneven coating occurs at the end and center of the film. It is difficult to uniformly coat the water-based primer.

  The present invention has been made in view of the above problems, and the purpose thereof is a (meth) acrylic film in which absorption of light in the visible light region is suppressed and uniform application of a water-based primer is possible. And to provide its use.

  As a result of intensive studies to complete the present invention, the inventor has uniformly applied a water-based primer to the (meth) acrylic film surface by improving the wettability of the (meth) acrylic film surface after film formation. As a result, the inventors have found that it can be worked, and have completed the present invention.

  That is, in order to solve the above problems, a (meth) acrylic film according to one embodiment of the present invention includes a thermoplastic resin composition containing a (meth) acrylic resin and an ultraviolet absorber having a molecular weight of less than 700. It is a (meth) acrylic film made of a material, and the contact angle with pure water is 76 ° or less.

  In the (meth) acrylic film according to one embodiment of the present invention, the ultraviolet absorber is preferably a benzotriazole-based ultraviolet absorber.

  In the (meth) acrylic film according to one aspect of the present invention, the benzotriazole-based ultraviolet absorber is preferably an ultraviolet absorber represented by the following general formula (1);

_(Wherein, R 1, _{R 2} are each independently a hydrogen atom or,, .R ₃ represents an alkyl group having 1 to 20 carbon atoms (the alkyl group may have a substituent) And R ₄ each independently represents a hydrogen atom or a halogen atom, L represents an alkylene group having 1 to 4 carbon atoms).

  In the (meth) acrylic film according to one embodiment of the present invention, when the transmittance at 500 nm is 100%, the transmittance at 400 nm is preferably 85% or more and the transmittance at 380 nm is preferably 35% or less. .

  The optical film which concerns on 1 aspect of this invention uses the said (meth) acrylic-type film.

  The polarizer protective film according to one embodiment of the present invention uses the optical film.

  The polarizing plate which concerns on 1 aspect of this invention is equipped with the said polarizer protective film.

  An image display device according to an aspect of the present invention includes the polarizing plate.

  According to one embodiment of the present invention, it is possible to provide a (meth) acrylic film in which absorption of light in the visible light region is suppressed and a water-based primer can be uniformly applied.

It is a figure which shows the example of IR spectrum in the center part and edge part of the film which apply | coated the aqueous primer based on the Example of this invention.

  Hereinafter, an embodiment of the present invention will be described in detail. However, the present invention is not limited to this, and various modifications can be made within the range described, and embodiments obtained by appropriately combining technical means disclosed in different embodiments are also included in the present invention. Included in the technical scope.

  In the present specification, “(meth) acrylic acid” means “acrylic acid or methacrylic acid”, and “ppm” is a value determined by mass conversion unless otherwise specified (for example, 10,000 ppm is 1% by mass). ). Further, “weight” is treated as a synonym for “mass”, “wt%” is treated as a synonym for “mass%”, and “A to B” indicating a numerical range is “unless otherwise noted” It means “A or more and B or less”.

<1. (Meth) acrylic film>
In one embodiment of the present invention, the (meth) acrylic film is made of a thermoplastic resin composition. The thermoplastic resin composition contains a (meth) acrylic resin and an ultraviolet absorber having a molecular weight of less than 700. According to the (meth) acrylic film of the present invention, the wettability of the film surface is improved, so that a water-based (water-soluble) primer can be uniformly applied (hydrophobic UV absorbers bleed on the film surface. Since it can be suppressed from being out, the wettability of the film surface is improved). Further, it can absorb light having a wavelength in the ultraviolet region while suppressing absorption in the visible light region. Hereinafter, the components contained in the thermoplastic resin composition will be described in detail.

[(Meth) acrylic resin]
The thermoplastic resin composition in one embodiment of the present invention contains a (meth) acrylic resin. The (meth) acrylic resin is obtained by polymerizing or copolymerizing a monomer composition containing acrylic acid, methacrylic acid, a derivative of these compounds, or a hydroxyl group-containing monomer having a structure represented by the following formula: The resulting resin and its derivatives. These structures are not particularly limited as long as the effects of the present invention are not impaired. Specifically, a known (meth) acrylic resin can be used.

^{_{CH 2 = C (COOR 1)}} -CHR 2 -OH
(Wherein, R ¹ and R ² each independently represents a hydrogen atom or a linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms).

  Specific examples of the derivative of (meth) acrylic acid include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, ( T-butyl (meth) acrylate, n-hexyl (meth) acrylate, 2-chloroethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, (meth) acryl Examples include acid 2,3,4,5-tetrahydroxypentyl and 2,3,4,5,6-pentahydroxyhexyl (meth) acrylate. A plurality of these derivatives may be used in combination. Among the above specific examples, methyl (meth) acrylate is most preferable in that the obtained (meth) acrylic resin has excellent thermal stability.

  Further, in the (meth) acrylic resin, a ring structure may be introduced into a molecular chain (also referred to as a polymer main skeleton or main chain) in order to improve the heat resistance of the (meth) acrylic resin. . The (meth) acrylic resin having a ring structure in the main chain will be described later.

  It is more preferable that the (meth) acrylic resin has a structure that does not contain a nitrogen atom so that it is difficult to be colored (yellowed) when a (meth) acrylic film is formed.

  In one embodiment of the present invention, the (meth) acrylic resin contained in the thermoplastic resin composition preferably has a glass transition temperature (Tg) in the range of 108 ° C. or higher and 160 ° C. or lower. Preferably it is in the range of 110 ° C. or higher and 150 ° C. or lower. In a more preferred embodiment, the glass transition temperature range is preferably as low as possible in the order of 140 ° C. or lower, 130 ° C. or lower, and 125 ° C. or lower. Higher is preferable in the order of 115 ° C. or higher and 117 ° C. or higher. In this respect, the thermoplastic composition is different from a general (meth) acrylic resin (polymethyl methacrylate (PMMA)).

  When the glass transition temperature is less than 108 ° C., for example, when an optical film made of the (meth) acrylic resin is incorporated as a polarizing plate of an optical device, sufficient durability at a high temperature cannot be exhibited. There is a fear. When the glass transition temperature exceeds 160 ° C., it is necessary to increase the molding temperature of the (meth) acrylic resin. Therefore, there is a risk of foaming during molding or bleeding out of the ultraviolet absorber. is there.

  In addition, if the glass transition temperature of the (meth) acrylic resin is within this range, the glass transition temperature of the thermoplastic resin composition formed on the film can be reduced without difficulty in film forming or stretching. The glass transition temperature of the optical film can also be increased. An optical film having a high glass transition temperature can reduce the rate of change in retardation under a high temperature environment.

  The glass transition temperature can be measured in accordance with the provisions of JIS K7121. Details of measurement conditions and the like will be described in the example section.

  In addition, the glass transition temperature and thermal decomposition temperature of (meth) acrylic resin may differ from the glass transition temperature and thermal decomposition temperature of a thermoplastic composition. This is because components other than the (meth) acrylic resin may be added when preparing the thermoplastic composition.

  On the other hand, when the molded thermoplastic composition is an optical film, the glass transition temperature and the thermal decomposition temperature of the thermoplastic composition may be regarded as substantially the same as the glass transition temperature and the thermal decomposition temperature of the optical film. .

  In this regard, the preferred glass transition temperature and thermal decomposition temperature of the thermoplastic resin composition in one embodiment of the present invention (that is, the preferred glass transition temperature and thermal decomposition temperature of the (meth) acrylic film in one embodiment of the present invention). ), The relationship between the thermal decomposition temperature Td (° C.) and the melting temperature Tp (° C.) of the thermoplastic resin composition preferably satisfies the formula 50 ≦ Td−Tp. By satisfying this condition, foreign matter such as gel contained in the melt of the thermoplastic resin composition is also reduced. That is, the roll (touch roll and cast roll) is less likely to be contaminated.

  Further, the (meth) acrylic resin may have a structural unit obtained by polymerizing other monomers copolymerizable with (meth) acrylic acid or a derivative thereof as long as the heat resistance is not impaired. . Specific examples of other copolymerizable monomers include styrene and aromatic vinyl monomers such as α-methylstyrene, nitrile monomers such as acrylonitrile, and vinyl esters such as vinyl acetate. Is mentioned.

  The weight average molecular weight (Mw) in terms of styrene by GPC measurement method of the (meth) acrylic resin in one embodiment of the present invention is preferably 3,000 to 1,000,000. If this weight average molecular weight is 3,000 or more, strength required as a polymer can be expressed. Moreover, if it is 1,000,000 or less, it can be set as a molded object by a shaping | molding process.

  The weight average molecular weight of the (meth) acrylic resin is more preferably 4,000 to 800,000, still more preferably 5,000 to 500,000, and still more preferably 100,000 to 500,000. is there. A (meth) acrylic resin having a weight average molecular weight in the above range is preferable because of good moldability by extrusion melting.

  The molecular weight distribution (Mw / Mn) according to the GPC measurement method of the (meth) acrylic resin in one embodiment of the present invention is preferably 1-10. From the viewpoint of adjusting the resin viscosity suitable for molding processing, the molecular weight distribution (Mw / Mn) is preferably 1.1 to 7.0, more preferably 1.2 to 5.0, still more preferably 1.5 to 4.0.

[(Meth) acrylic resin having a ring structure in the main chain]
As described above, in the (meth) acrylic resin, a ring structure may be introduced into the main chain in order to improve the heat resistance of the (meth) acrylic resin.

  Examples of such a ring structure include at least selected from a lactone ring structure, a glutaric anhydride structure, a glutarimide structure, a structure derived from an N-substituted maleimide monomer, and a structure derived from a maleic anhydride monomer. One type is mentioned. More specifically, the (meth) acrylic resin may be a copolymer of, for example, (meth) acrylic acid or a derivative thereof and an N-substituted maleimide such as phenylmaleimide, cyclohexylmaleimide, and methylmaleimide. Good. The (meth) acrylic resin is preferably a structure derived from a lactone ring structure, a glutarimide structure, and an N-substituted maleimide monomer.

  The content of the ring structure in the (meth) acrylic resin is, for example, preferably in the range of 1 to 60 mol%, more preferably in the range of 1 to 40 mol%, and 2 to 30 mol%. More preferably, it is in the range.

  Moreover, the content of the ring structure in the (meth) acrylic resin is, for example, preferably in the range of 1 to 80% by mass, more preferably in the range of 1 to 50% by mass, and 2 to 40%. More preferably, it is in the range of mass%. Thereby, the (meth) acrylic-type film containing (meth) acrylic-type resin shows the outstanding mechanical strength while showing the outstanding transparency and heat resistance.

(Structure of lactone ring structure-containing polymer)
The (meth) acrylic resin is more preferably a so-called lactone ring structure-containing polymer in which a lactone ring structure is introduced into the main chain of the polymer by an intramolecular cyclization reaction. A ring structure-containing polymer is particularly preferred. In the present specification, a (meth) acrylic resin having a lactone ring structure introduced into the main chain is referred to as a lactone ring structure-containing polymer. Such a lactone ring structure-containing polymer has high transparency, heat resistance, and optical isotropy, and can sufficiently exhibit characteristics according to various optical applications.

  The lactone ring structure-containing polymer is not particularly limited, but more preferably has a lactone ring structure represented by the following general formula (2).

(Wherein R ¹¹ , R ¹² and R ¹³ are each independently a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms (the alkyl group is an arbitrary Represents an oxygen atom in the constitution)).

  The content of the lactone ring structure represented by the general formula (2) in the lactone ring structure-containing polymer is preferably 1% by mass or more and 80% by mass or less, more preferably 3% by mass or more and 60% by mass or less. More preferably, they are 5 mass% or more and 40 mass% or less, Most preferably, they are 10 mass% or more and 30 mass% or less. When the said content rate is less than 1 mass%, heat resistance, solvent resistance, and surface hardness may become inadequate. Moreover, when there are more said content rates than 90 mass%, a moldability may become scarce.

  The lactone ring structure-containing polymer may have a structure other than the lactone ring structure represented by the general formula (2). The structure other than the lactone ring structure represented by the general formula (2) is not particularly limited. For example, it is constructed by polymerizing at least one monomer selected from a (meth) acrylic acid ester, a hydroxyl group-containing monomer, an unsaturated carboxylic acid, and a monomer represented by the following general formula (3). Preferred is a polymer structural unit (repeating structural unit).

^{_{CH 2 = C (X) -R}} 14 ... (3)
(Wherein R ¹⁴ represents a hydrogen atom or a methyl group. X represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group, an —OAc group, a —CN group, a —CO—R ¹⁵ group, or C—O—R ¹⁶ group, Ac represents acetyl, R ¹⁵ and R ¹⁶ represent a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms) .

  The lactone ring structure-containing polymer has a polymer structural unit (repeating structural unit) constructed by polymerizing (meth) acrylic acid ester as a structure other than the lactone ring structure represented by the general formula (2). The content is preferably within a range of 20% by mass or more and 99% by mass or less, more preferably within a range of 40% by mass or more and 97% by mass or less, and further preferably 60% by mass or more. It is in the range of 95% by mass or less, particularly preferably in the range of 70% by mass or more and 90% by mass or less.

  Further, the lactone ring structure-containing polymer has a polymer structural unit (repeating structural unit) constructed by polymerizing a hydroxyl group-containing monomer as a structure other than the lactone ring structure represented by the general formula (2). In this case, the content ratio is preferably more than 0% by mass and in the range of 30% by mass or less, more preferably more than 0% by mass and in the range of 20% by mass or less, and further preferably 0% by mass. % And in the range of 15% by mass or less, particularly preferably in the range of more than 0% by mass and 10% by mass or less.

  The lactone ring structure-containing polymer has a polymer structural unit (repeating structural unit) constructed by polymerizing an unsaturated carboxylic acid as a structure other than the lactone ring structure represented by the general formula (2). The content is preferably more than 0% by weight and less than 30% by weight, more preferably more than 0% by weight and less than 20% by weight, and even more preferably 0% by weight. Exceeding 15% by mass, particularly preferably exceeding 0% by mass and within 10% by mass.

  In addition, the lactone ring structure-containing polymer is a polymer structural unit constructed by polymerizing the monomer represented by the general formula (3) as a structure other than the lactone ring structure represented by the general formula (2) In the case of having (repeating structural unit), the content is preferably more than 0% by mass and within 30% by mass, more preferably more than 0% by mass and 20% by mass or less. Of these, more preferably more than 0% by mass and 15% by mass or less, and particularly preferably more than 0% by mass and 10% by mass or less.

  In the lactone ring structure-containing polymer, the content of structures other than the lactone ring structure represented by the general formula (2) is preferably 10% by mass or more and 95% by mass or less, more preferably 30% by mass. % To 90% by mass, more preferably 40% to 90% by mass, particularly preferably 50% to 90% by mass.

(Structure of glutaric anhydride structure-containing polymer and glutarimide structure-containing polymer)
The (meth) acrylic resin may be a so-called glutaric anhydride structure-containing polymer or glutarimide structure-containing polymer in which a glutaric anhydride structure or a glutarimide structure is introduced into the main chain of the polymer. In this specification, a (meth) acrylic resin in which a glutaric anhydride structure is introduced into the main chain is referred to as a glutaric anhydride structure-containing polymer, and a (meth) acrylic resin in which a glutarimide structure is introduced into the main chain The resin is referred to as a glutarimide structure-containing polymer.

  The glutaric anhydride structure-containing polymer and glutarimide structure-containing polymer are not particularly limited, but more preferably have a glutaric anhydride structure or a glutarimide structure represented by the following general formula (4).

(In the formula, R ¹⁷ and R ¹⁸ each independently represent a hydrogen atom or a methyl group. X ¹ represents an oxygen atom or a nitrogen atom. When X ¹ is an oxygen atom, R ¹⁹ is present. And when X ¹ is a nitrogen atom, R ³ represents a hydrogen atom, a linear alkyl group having 1 to 6 carbon atoms, a cyclopentyl group, a cyclohexyl group or a phenyl group).

That is, when X ¹ in the general formula (4) is an oxygen atom, the ring structure represented by the general formula (4) is a glutaric anhydride structure. The glutaric anhydride structure-containing polymer can be formed, for example, by subjecting a copolymer of (meth) acrylic acid ester and (meth) acrylic acid to a dealcoholization cyclocondensation reaction in the molecule.

  Although the method of the dealcoholization cyclocondensation reaction in a molecule | numerator is not specifically limited, For example, it can carry out by heating the said copolymer. The heating temperature is not particularly limited as long as the intramolecular cyclization reaction is caused by dealcoholization, but for example, the heating temperature is preferably in the range of 180 to 350 ° C. Although what is necessary is just to change a heating time suitably according to a composition etc. of (meth) acrylic-type resin, the inside of the range for 1-2 hours is suitable, for example. In the dealcoholization cyclocondensation reaction, a catalyst (for example, an acid catalyst, a basic catalyst, a salt catalyst, etc.) may be used as necessary.

When X ¹ in the general formula (4) is a nitrogen atom, the ring structure represented by the general formula (4) is a glutarimide structure. The glutarimide structure-containing polymer can be formed, for example, by imidizing a polymer of (meth) acrylic acid ester using an imidizing agent such as methylamine. A known method can be used as the imidization method. Specifically, for example, a polymer of (meth) acrylic acid ester can be imidized using ammonia, a substituted amine, or the like.

When the (meth) acrylic resin is used as an optical film, X ¹ in the general formula (4) is preferably a nitrogen atom so that a dimensional change or a retardation change is not likely to occur in a high humidity environment.

(Structure of structure-containing polymer derived from N-substituted maleimide monomer and structure-containing polymer derived from maleic anhydride monomer)
The (meth) acrylic resin is a so-called N-substituted maleimide monomer in which a structure derived from an N-substituted maleimide monomer or a structure derived from a maleic anhydride monomer is introduced into the main chain of the polymer. It may be a structure-containing polymer derived from or a structure-containing polymer derived from a maleic anhydride monomer. In this specification, a (meth) acrylic resin in which a structure derived from an N-substituted maleimide monomer is introduced into the main chain is referred to as a structure-containing polymer derived from an N-substituted maleimide monomer. A (meth) acrylic resin in which a structure derived from a maleic anhydride monomer is introduced is referred to as a structure-containing polymer derived from a maleic anhydride monomer.

  The structure-containing polymer derived from the N-substituted maleimide monomer and the structure-containing polymer derived from the maleic anhydride monomer are not particularly limited, but N represented by the following general formula (5) -It is more preferable to have a structure derived from a substituted maleimide monomer or a structure derived from a maleic anhydride monomer.

(In the formula, R ²⁰ and R ²¹ each independently represents a hydrogen atom or a methyl group. X ² represents an oxygen atom or a nitrogen atom. When X ² is an oxygen atom, R ²² is present. without when X ² is a nitrogen atom, R ²² represents a hydrogen atom, a linear alkyl group having 1 to 6 carbon atoms, a cyclopentyl group, a cyclohexyl group, a benzyl group or a phenyl group).

That is, when X ² in the general formula (5) is an oxygen atom, the ring structure represented by the general formula (5) is derived from a maleic anhydride monomer. The structure-containing polymer derived from the maleic anhydride monomer is formed, for example, by copolymerizing maleic anhydride and (meth) acrylic acid ester (for example, by radical polymerization, preferably by solution polymerization). Can do. When X ² in the general formula (5) is a nitrogen atom, the ring structure represented by the general formula (5) is a structure derived from an N-substituted maleimide monomer. A structure-containing polymer derived from an N-substituted maleimide monomer is formed by, for example, copolymerizing (for example, by radical polymerization, preferably by solution polymerization) an N-substituted maleimide and a (meth) acrylic ester. can do.

When the (meth) acrylic resin is used as an optical film, X ² in the general formula (5) is preferably a nitrogen atom so that a dimensional change or a retardation change is not likely to occur in a high humidity environment.

  In addition, a glutaric anhydride structure-containing polymer, a glutarimide structure-containing polymer, a structure-containing polymer derived from an N-substituted maleimide monomer, and a structure-containing polymer derived from a maleic anhydride monomer, All the polymers used for forming the structure have (meth) acrylic acid ester units as constituent units. Therefore, the resin obtained by the method is included in the category of (meth) acrylic resin.

  Lactone ring structure-containing polymer, glutaric anhydride structure-containing polymer, glutarimide structure-containing polymer, structure-containing polymer derived from N-substituted maleimide monomer, and structure-containing polymer derived from maleic anhydride monomer May be used in combination of a plurality of types as required. That is, the thermoplastic resin composition in one embodiment of the present invention may be a mixture of these polymers.

[Ultraviolet absorber]
The thermoplastic resin composition in one embodiment of the present invention contains an ultraviolet absorber having a molecular weight of less than 700.

  The ultraviolet absorber is not particularly limited. For example, at least one selected from benzophenone compounds, salicinate compounds, benzoate compounds, cyanoacrylate compounds, benzotriazole compounds, and triazine compounds is used. can do. Among these ultraviolet absorbers, benzotriazole compounds are preferred because of their high ultraviolet absorption ability.

  As the benzotriazole compound, an ultraviolet absorber represented by the following general formula (1) is preferable;

_(Wherein, R 1, _{R 2} are each independently a hydrogen atom or,, .R ₃ represents an alkyl group having 1 to 20 carbon atoms (the alkyl group may have a substituent) And R ₄ each independently represents a hydrogen atom or a halogen atom, L represents an alkylene group having 1 to 4 carbon atoms).

  Among the ultraviolet absorbers represented by the general formula (1), 2,2′-methylenebis [6- (2H-benzotriazol-2-yl) 4- (1,1,3,3-tetra] represented by the following formula Methylbutyl) phenol] (Kemipro Kasei Co., Ltd .: KEMISORB (registered trademark) 279RC) is particularly preferable from the viewpoint of color tone and availability.

  The molecular weight of the ultraviolet absorber in one embodiment of the present invention is less than 700, but is preferably 400 or more and less than 700. In addition, when the molecular weight is less than 400, at the time of producing the thermoplastic resin composition or the (meth) acrylic film, there is a possibility that the amount of the ultraviolet absorbent sucked into the vent increases so that the piping and the like are blocked.

  The thermoplastic resin composition according to one embodiment of the present invention preferably contains the above-described ultraviolet absorber within a range of 0.1 to 3 parts by weight with respect to 100 parts by weight of the (meth) acrylic resin. When the amount of the UV absorber is less than 0.1 parts by weight, the contribution of improving weather resistance is small, and when it exceeds 3 parts by weight, a (meth) acrylic film capable of uniformly applying a water-based primer can be produced. It becomes difficult.

[Other additives]
The thermoplastic resin composition according to one embodiment of the present invention may contain other additives in addition to the (meth) acrylic resin and the ultraviolet absorber as long as the effects of the present invention are not impaired. Good.

  Other additives include polymers, unreacted monomers, solvents, by-products generated during the polymerization process of (meth) acrylic resins, antioxidants, stabilizers, reinforcing materials, near infrared absorbers. , Flame retardants, retardation adjusting agents, antistatic agents, fillers, resin modifiers, fillers, and the like, but are not limited thereto.

  Examples of the polymer include olefin polymers such as polyethylene, polypropylene, ethylene-propylene polymer, or poly (4-methyl-1-pentene); halogen-containing polymers such as vinyl chloride or chlorinated vinyl resins. Acrylic polymer such as polymethyl methacrylate; styrene polymer such as polystyrene, styrene-methyl methacrylate copolymer, styrene-acrylonitrile copolymer, or acrylonitrile-butadiene-styrene block copolymer; polymer polyethylene terephthalate Polyesters such as nylon, nylon 66, or nylon 610; polyacetals; polycarbonates; polyphenylene oxides; Nirensurufido; polyetheretherketone; polysulfone; polyether sulfone; polyoxyethylene Penji alkylene; polyamideimide; polybutadiene rubber, rubber-like polymer such as ABS resin or ASA resin containing an acrylic rubber; and the like.

  Antioxidants include hindered phenols, phosphoruss, and sulfurs. Examples of the stabilizer include a light-resistant stabilizer, a weather-resistant stabilizer, and a heat stabilizer. Examples of the reinforcing material include glass fiber and carbon fiber. Examples of the flame retardant include tris (dibromopropyl) phosphate, triallyl phosphate, and antimony oxide. Examples of the phase difference adjusting agent include a phase difference increasing agent, a phase difference reducing agent, and a phase difference stabilizer. Examples of the antistatic agent include those containing an anionic, cationic or nonionic surfactant.

  The content of other additives in 100% by mass of the thermoplastic resin composition in one embodiment of the present invention is preferably 0 to 5% by mass, more preferably 0 to 2% by mass, and still more preferably 0 to 1% by mass. Is within the range.

  The thermoplastic resin composition in one embodiment of the present invention may further contain a colorant. Examples of the colorant include inorganic pigments, organic pigments, and dyes. More specifically, examples include a compound having an anthraquinone skeleton and a compound having a phthalocyanine skeleton, among which a compound having an anthraquinone skeleton is preferable from the viewpoint of heat resistance.

  The content of the colorant in one embodiment of the present invention is preferably 0.01 to 5 ppm by mass, more preferably 0.05 to 3 ppm by mass with respect to 100% by mass of the thermoplastic resin composition, 1 mass ppm is more preferable.

  A well-known thing can be used suitably for a coloring agent. For example, specifically, “Macrolex (registered trademark) violet B”, “Macrolex (registered trademark) violet 3R” (manufactured by LANXESS), or “Sumiplast (registered trademark) violet B”, “Sumiplast (registered trademark)” Green G "(manufactured by Sumika Chemtex Co., Ltd.). The colorant can reduce the hue and saturation of the thermoplastic resin composition in one embodiment of the present invention.

  Here, when manufacturing the thermoplastic resin composition in one Embodiment of this invention, a metal element may mix.

  For example, a metal element derived from additives such as a polymerization initiator, a cyclization catalyst, and a deactivator may be included in the production process of the (meth) acrylic resin described later. Moreover, mixing of metal elements derived from other additives can be considered during the production of the thermoplastic resin composition.

  The content of the metal element of 100% by mass of the thermoplastic resin composition in one embodiment of the present invention is preferably 0 to 200 ppm by mass, more preferably 0 to 100 ppm by mass, still more preferably 0 to 60 ppm by mass, especially. Preferably it exists in the range of 0-10 mass ppm.

  When the content of the metal element in the thermoplastic resin composition exceeds 200 mass ppm, there is a possibility that the hue and saturation of the thermoplastic resin composition increase and the transparency is deteriorated due to the generation of foreign matters.

  Examples of metal elements that bring about such undesirable effects include alkali metals, alkaline earth metals, and heavy metals, such as zinc, copper, and iron. These metal elements may form a complex with an ultraviolet absorber that is a benzotriazole-based compound, and may increase hue and saturation.

<2. Manufacturing method of (meth) acrylic film>
The (meth) acrylic film is manufactured by forming the above-described thermoplastic resin composition. The thermoplastic resin composition can be obtained by mixing a (meth) acrylic resin and an ultraviolet absorber. Moreover, as a manufacturing method of (meth) acrylic-type resin, the method etc. which superpose | polymerize the monomer composition containing (meth) acrylic acid or its derivative (s) are mentioned.

  Hereinafter, a method for producing a (meth) acrylic resin, a method for producing a lactone ring structure-containing polymer which is a preferred form of the (meth) acrylic resin, a method for producing a thermoplastic resin composition, and a (meth) acrylic film A manufacturing method will be described.

[Method for producing (meth) acrylic resin]
The method for producing the (meth) acrylic resin is not particularly limited, and a known method can be used. Specific examples include a method of polymerizing a monomer composition containing (meth) acrylic acid or a derivative thereof.

  When a (meth) acrylic resin is used as an optical material, it is preferable to avoid contamination of minute foreign matters as much as possible. From this viewpoint, it is desirable to use bulk polymerization, cast polymerization, or solution polymerization without using a suspending agent or an emulsifier.

  As the polymerization mode, for example, either a batch polymerization method or a continuous polymerization method can be used. From the viewpoint of simple polymerization operation, the batch polymerization method is desirable, and from the viewpoint of obtaining a polymer having a more uniform composition, the continuous polymerization method is desirable.

  The polymerization temperature and the polymerization time vary depending on the type of monomer used and the use ratio (composition of the monomer composition). In general, the polymerization temperature is preferably in the range of 0 ° C. or higher and 150 ° C. or lower, and more preferably in the range of 80 ° C. or higher and 140 ° C. or lower. The polymerization time is preferably in the range of 0.5 hours to 20 hours, and more preferably in the range of 1 hour to 10 hours.

  The solvent used in the case of the polymerization form using a solvent is not particularly limited. For example, aromatic hydrocarbon solvents such as toluene, xylene, or ethylbenzene; ketone solvents such as methyl ethyl ketone or methyl isobutyl ketone; ether solvents such as tetrahydrofuran; A plurality of types of solvents may be used in combination.

  In particular, in the case of producing a (meth) acrylic resin having a lactone ring structure introduced in the main chain, if the boiling point of the solvent used is too high, the residual volatile content of the (meth) acrylic resin finally obtained Will increase. Therefore, the boiling point of the solvent is more preferably in the range of 50 ° C. or more and 200 ° C. or less.

  During the polymerization reaction of the monomer composition, a polymerization initiator may be added as necessary. The polymerization initiator is not particularly limited. For example, cumene hydroperoxide, diisopropylbenzene hydroperoxide, di-t-butyl peroxide, lauroyl peroxide, benzoyl peroxide, t-butylperoxyisopropyl carbonate, or t-amylperoxy-2-ethylhexanoate Organic peroxides such as 2,2′-azobis (isobutyronitrile), 1,1′-azobis (cyclohexanecarbonitrile), or 2,2′-azobis (2,4-dimethylvaleronitrile) Azo compounds; and the like. A plurality of polymerization initiators may be used in combination.

  What is necessary is just to set suitably the usage-amount of a polymerization initiator according to the kind of monomer to be used, its usage ratio (composition of a monomer composition), reaction conditions, etc., and it is not specifically limited.

  During the polymerization reaction of the monomer composition, it is preferable to control the concentration of the polymer in the reaction solution to 50% by mass or less in order to suppress gelation of the reaction solution. Specifically, when the concentration of the polymer in the reaction solution exceeds 50% by mass, it is preferable to add a solvent to the reaction solution as appropriate so that the concentration becomes 50% by mass or less. The concentration is more preferably 45% by mass or less, and further preferably 40% by mass or less.

  In addition, since productivity will fall when the density | concentration of a polymer is too low, it is preferable that the said density | concentration is 10 mass% or more, and it is more preferable that it is 20 mass% or more.

  The method for adding the solvent to the reaction solution during the polymerization reaction is not particularly limited. For example, the solvent may be added continuously to the reaction solution, or the solvent may be added intermittently. By controlling the concentration of the polymer in the reaction solution, gelation of the reaction solution can be suppressed.

  The solvent added to the reaction solution may be the same type (composition) as the solvent used at the start of the polymerization reaction or may be a different type (composition), but the same type (composition) as the solvent used at the start of the polymerization reaction. It is more preferable that Moreover, the solvent to add may use multiple types together.

[Method for producing lactone ring structure-containing polymer]
When the (meth) acrylic resin is a lactone ring structure-containing polymer, the method for producing the lactone ring structure-containing polymer is not particularly limited. Preferably, after obtaining a polymer having a hydroxyl group and an ester group in the molecular chain, the polymer is subjected to a cyclization condensation reaction (lactone ring condensation reaction) for introducing a lactone ring structure into the polymer by heat treatment. As a result, a lactone ring structure-containing polymer can be obtained. That is, the monomer composition becomes a lactone ring structure-containing polymer through the polymerization step and the lactone cyclization condensation step.

  By forming the lactone ring structure in the molecular chain of the polymer (in the main skeleton of the polymer), high heat resistance is imparted to the polymer. When the reaction rate of the cyclocondensation reaction for introducing the lactone ring structure into the polymer is low, the heat resistance of the polymer may not be sufficiently improved. Further, due to heat accompanying the heat treatment during molding, a condensation reaction of the polymer may occur during molding, and the resulting alcohol may appear as bubbles or silver streaks in the molded product.

  The method for heat-treating the polymer for carrying out the cyclization condensation reaction is not particularly limited, and a known method can be used. For example, you may heat-process the polymerization reaction mixture containing the polymer and solvent obtained by performing a polymerization process as it is. Moreover, you may heat-process a polymer using a cyclization catalyst as needed in presence of a solvent. Furthermore, you may heat-process using the heating furnace and reaction apparatus provided with the vacuum apparatus or devolatilization apparatus for removing a volatile component. Furthermore, the polymer can be heat-treated using a devolatilizer and an extruder.

  When carrying out the cyclization condensation reaction, other acrylic resins may coexist in addition to the polymer. In addition, when the cyclization condensation reaction is performed, an esterification catalyst such as (i) an organophosphorus compound, (ii) p-toluenesulfonic acid or the like generally used as a catalyst for the cyclization condensation reaction, if necessary, iii) A transesterification catalyst may be used. Alternatively, organic carboxylic acids such as acetic acid, propionic acid, benzoic acid, acrylic acid, and methacrylic acid may be used as a catalyst. Furthermore, basic compounds, organic carboxylates, carbonates and the like described in JP-A Nos. 61-254608 and 61-261303 may be used as a catalyst.

  As a catalyst for the cyclization condensation reaction that is a dealcoholization reaction, an organic phosphorus compound is more preferable. By using an organic phosphorus compound as a catalyst, the reaction rate of the cyclization condensation reaction can be improved, and coloring of the resulting lactone ring structure-containing polymer can be greatly reduced. Furthermore, by using an organophosphorus compound as a catalyst, it is possible to suppress a decrease in the molecular weight of the polymer, which can occur when the lactone cyclization condensation step and the devolatilization step described below are used in combination. Excellent mechanical strength can be imparted.

  Examples of the organic phosphorus compound that can be used as a catalyst in the cyclocondensation reaction include alkyl (aryl) sulfonic acids such as methyl sulfonic acid, ethyl sulfonic acid, and phenyl sulfonic acid (however, Tautomers (which may be alkyl (aryl) phosphinic acid) and monoesters or diesters thereof; dimethylphosphinic acid, diethylphosphinic acid, diphenylphosphinic acid, phenylmethylphosphinic acid, phenylethylphosphinic acid, etc. Dialkyl (aryl) phosphinic acids and their esters; alkyl (aryl) phosphonic acids such as methyl phosphonic acid, ethyl phosphonic acid, trifluoromethyl phosphonic acid, phenyl phosphonic acid and their monoesters or diesters; methyl phosphite Alkyl (aryl) phosphinic acids such as acid, ethylphosphinic acid, phenylphosphinic acid and their esters; methyl phosphite, ethyl phosphite, phenyl phosphite, dimethyl phosphite, diethyl phosphite Phosphorous acid monoester, diester or triester such as diphenyl phosphite, trimethyl phosphite, triethyl phosphite, triphenyl phosphite; methyl phosphate, ethyl phosphate, 2-ethylhexyl phosphate, phosphoric acid Octyl, isodecyl phosphate, lauryl phosphate, stearyl phosphate, isostearyl phosphate, phenyl phosphate, dimethyl phosphate, diethyl phosphate, di-2-ethylhexyl phosphate, diisodecyl phosphate, dilauryl phosphate, diphosphate Stearyl, diisostearyl phosphate, diphenyl phosphate, phosphate Phosphoric monoesters, diesters or triesters such as methyl, triethyl phosphate, triisodecyl phosphate, trilauryl phosphate, tristearyl phosphate, triisostearyl phosphate, triphenyl phosphate; methylphosphine, ethylphosphine, phenylphosphine, Mono-, di- or tri-alkyl (aryl) phosphine such as dimethylphosphine, diethylphosphine, diphenylphosphine, trimethylphosphine, triethylphosphine, triphenylphosphine; methyldichlorophosphine, ethyldichlorophosphine, phenyldichlorophosphine, dimethylchlorophosphine, Alkyl (aryl) halogen phosphines such as diethyl chlorophosphine and diphenylchlorophosphine; methyl phosphine oxide, ethyl oxide Phosphine, phenyl phosphine oxide, dimethyl phosphine oxide, diethyl phosphine oxide, diphenyl phosphine oxide, trimethyl phosphine oxide, triethyl phosphine oxide, triphenyl phosphine oxide, mono-, di- or tri-alkyl (aryl) phosphine oxides; tetramethyl chloride And halogenated tetraalkyl (aryl) phosphonium such as phosphonium, tetraethylphosphonium chloride, tetraphenylphosphonium chloride; and the like.

  Among these organophosphorus compounds, alkyl (aryl) phosphonous acid, phosphorous acid diester or monoester, phosphoric acid diester or monoester, and alkyl (aryl) phosphonic acid are preferable because of high catalytic activity and low colorability. Alkyl (aryl) phosphonous acid, phosphorous acid diester or monoester, phosphoric acid diester or monoester is more preferable, and alkyl (aryl) phosphonous acid, phosphoric acid diester or monoester is particularly preferable. A plurality of these organic phosphorus compounds may be used in combination.

  The amount of the catalyst used in the cyclization condensation reaction is not particularly limited, but is preferably in the range of 0.001 to 5% by mass, more preferably 0.01 to 5% with respect to the polymer. It is in the range of 2.5% by mass, more preferably in the range of 0.01 to 1% by mass, particularly preferably in the range of 0.05 to 0.5% by mass. If the amount of the catalyst used is less than 0.001% by mass, the reaction rate of the cyclization condensation reaction may not be improved sufficiently. On the other hand, if the amount of the catalyst used exceeds 5% by mass, the lactone ring structure-containing polymer may be colored, or it may be difficult to melt and form the polymer due to crosslinking.

  The addition timing of the catalyst is not particularly limited, and may be added at the initial stage of the cyclization condensation reaction, may be added during the reaction, or may be added in both of them.

  As a method for producing the lactone ring structure-containing polymer, it is preferable to perform the lactone cyclization condensation step in the presence of a solvent and to use the devolatilization step in combination with the lactone cyclization condensation step. As a form of such a production method, (i) a form in which a devolatilization process is used throughout the lactone cyclization condensation process, and (ii) a devolatilization process is used in part of the lactone cyclization condensation process. Form. In the method using the devolatilization step in combination, the alcohol produced as a by-product in the cyclization condensation reaction is forcibly devolatilized and removed, so that the equilibrium of the reaction is advantageous for the production side.

  The form in which the devolatilization step is used only in a part of the lactone cyclization condensation step means, for example, that after the production of the polymer, the apparatus for producing the polymer is further heated to advance the cyclization condensation reaction to some extent in advance. In this mode, a cyclization condensation reaction is subsequently performed using a devolatilization step to complete the reaction. Here, even in the stage where the apparatus for producing the polymer is further heated to cause the cyclization condensation reaction to proceed to some extent in advance, a part of the devolatilization step may be used in combination. All forms in which the lactone cyclization condensation step and the devolatilization step are used in combination, and the deaeration step is not used in combination throughout the lactone cyclization condensation step, are classified into this embodiment.

  Here, the devolatilization step refers to a step of removing a volatile component such as a solvent and a residual monomer and an alcohol by-produced by a cyclization condensation reaction leading to a lactone ring structure. The devolatilization step may be performed under reduced pressure heating conditions as necessary. If this removal treatment is insufficient, the residual volatile content in the produced lactone ring structure-containing polymer will increase, and the lactone ring structure-containing polymer will be colored by alteration during molding, such as foam and silver streak Problems such as defective molding occur.

  In the form in which the devolatilization step is used in combination throughout the lactone cyclization condensation step, the apparatus to be used is not particularly limited. In order to carry out the production method of the present invention more effectively, (i) a devolatilization apparatus comprising a heat exchanger and a devolatilization tank, (ii) an extruder with a vent, or (iii) a devolatilization apparatus and a vent It is preferable to use an apparatus in which an attached extruder is arranged in series, and it is more preferable to use (i) a devolatilizing apparatus comprising a heat exchanger and a devolatilizing tank or (ii) an extruder with a vent.

  When using the said devolatilization apparatus which consists of a heat exchanger and a devolatilization tank, the temperature at the time of a cyclization condensation reaction has the preferable inside of the range of 150-350 degreeC, and the inside of the range of 200-300 degreeC is more preferable. When the said temperature is lower than 150 degreeC, there exists a possibility that cyclization condensation reaction may become inadequate and residual volatile matter may increase. If the temperature is higher than 350 ° C, the lactone ring structure-containing polymer may be colored or decomposed.

  When using the said devolatilization apparatus which consists of a heat exchanger and a devolatilization tank, the pressure at the cyclization condensation reaction has the preferable range of 931-1.33 hPa (700-1 mmHg), and 798-66.5 hPa (600). Within the range of ˜50 mmHg) is more preferable. If the pressure is higher than 931 hPa, volatile components including alcohol may easily remain in the lactone ring structure-containing polymer. If the pressure is lower than 1.33 hPa, industrial implementation may be difficult.

  When the above extruder with a vent is used, the number of vents may be one or plural, but a plurality is more preferable.

  When using the extruder with a vent, the temperature during the cyclization condensation reaction is preferably in the range of 150 to 350 ° C, more preferably in the range of 200 to 300 ° C. When the said temperature is lower than 150 degreeC, there exists a possibility that cyclization condensation reaction may become inadequate and residual volatile matter may increase. If the temperature is higher than 350 ° C, the lactone ring structure-containing polymer may be colored or decomposed.

  When using the extruder with a vent, the pressure during the cyclization condensation reaction is preferably within a range of 931 to 1.33 hPa (700 to 1 mmHg), and more preferably within a range of 798 to 13.3 hPa (600 to 10 mmHg). . If the pressure is higher than 931 hPa, volatile components including alcohol may easily remain in the lactone ring structure-containing polymer. If the pressure is lower than 1.33 hPa, industrial implementation may be difficult.

  In addition, in the form which uses a devolatilization process throughout the lactone cyclization condensation process, there exists a possibility that the physical property of the lactone ring structure containing polymer obtained in the heat processing of severe conditions may fall as mentioned later. Therefore, preferably, the devolatilization step is performed using a vented extruder or the like under the mildest conditions using the above-mentioned catalyst for the cyclization condensation reaction. Here, “the heat treatment under severe conditions” refers to heat treatment performed under a high temperature condition of 300 ° C. or higher, for example. On the other hand, the “heat treatment under mild conditions” refers to a heat treatment performed under a temperature condition of 250 to 300 ° C., for example.

  Moreover, in the form which uses a devolatilization process throughout the lactone cyclization condensation process, Preferably, the polymer obtained at the polymerization process is introduce | transduced into a reaction apparatus with a solvent. In this case, if necessary, the polymer taken out from the reactor may be passed again through a devolatilizer or a vented extruder.

  In a form that uses a devolatilization process throughout the lactone cyclization condensation process (for example, a form in which a polymer is heated at a high temperature of nearly 250 ° C. or higher using a twin-screw extruder), the difference in thermal history There may be a phenomenon in which a part of the polymer is decomposed before the cyclization condensation reaction occurs. When such a phenomenon occurs, the physical properties of the resulting lactone ring structure-containing polymer may be deteriorated.

  Therefore, it is preferable that the lactone ring condensation step has a form in which the devolatilization step is used only in part of the lactone cyclization condensation step. For example, if the cyclization condensation reaction is allowed to proceed to some extent before the lactone cyclization condensation step combined with the devolatilization step, the latter reaction conditions can be relaxed, and the resulting lactone ring structure is contained. Since the fall of the physical property of a polymer can be suppressed, it is preferable.

  As a particularly preferred form, there is a form in which the devolatilization step is started after a lapse of time from the start of the lactone cyclization condensation step. Specifically, (i) the hydroxyl group and ester group present in the molecular chain of the polymer obtained in the polymerization step are subjected to a cyclization condensation reaction in advance to increase the reaction rate of the cyclization condensation reaction to some extent. Subsequently, (ii) a lactone cyclization condensation step using a devolatilization step is performed. More specifically, for example, (i) the cyclization condensation reaction is allowed to proceed to a certain reaction rate in the presence of a solvent using a kettle reactor, and then (ii) the devolatilization apparatus is This is a form in which the cyclocondensation reaction is completed in a reactor equipped (for example, a devolatilization apparatus including a heat exchanger and a devolatilization tank, an extruder with a vent, or the like). In this embodiment, it is particularly preferable that a catalyst for the cyclization condensation reaction is present in the reaction system.

  As described above, (i) the hydroxyl group and ester group present in the molecular chain of the polymer obtained in the polymerization step are subjected to a cyclization condensation reaction in advance to increase the reaction rate of the cyclization condensation reaction to some extent. Then, the method of performing the lactone cyclization condensation step in combination with (ii) the devolatilization step is a preferred form for obtaining a lactone ring structure-containing polymer. This form further increases the reaction rate of the cyclization condensation reaction. In addition, a lactone ring structure-containing polymer having a higher glass transition temperature and excellent heat resistance can be obtained. In this embodiment, as a measure of the reaction rate of the cyclization condensation reaction, the mass reduction rate between 150 and 300 ° C. in the dynamic TG measurement shown in the examples is preferably 2% or less. % Or less is more preferable, and 1% or less is more preferable.

  The reactor that can be employed in the cyclization condensation reaction carried out in advance before the lactone cyclization condensation step combined with the devolatilization step is not particularly limited. Preferred examples include an autoclave, a kettle reactor, a devolatilization apparatus comprising a heat exchanger and a devolatilization tank, and an extruder with a vent (among these, a vented extruder is a lactone ring combined with a devolatilization step. It can also be suitably used in the polycondensation step). More preferred are autoclaves and kettle reactors. However, even when a reactor such as an extruder with a vent is used, (i) the venting conditions are mild (eg, 931 hPa (700 mmHg) or more), (ii) no venting is performed, (iii) temperature conditions It is possible to carry out the cyclization condensation reaction in the same state as the reaction state in the autoclave or the kettle type reactor by taking measures such as adjusting the barrel condition, screw shape, screw operation condition, and the like.

  As the cyclization condensation reaction performed in advance, preferably, (i) a method in which a mixture containing a polymer obtained in the polymerization step and a solvent is heated and reacted by heating, (ii) a heat reaction without catalyst. And (iii) a method in which the above (i) or (ii) is carried out under pressure can be employed.

  The “mixture containing a polymer and a solvent” to be introduced into the cyclization condensation reaction in the lactone cyclization condensation step may be the polymerization reaction mixture obtained in the polymerization step as it is, or from the polymerization reaction mixture. You may use the mixture formed by adding another solvent suitable for cyclization condensation reaction after removing a solvent once. That is, the solvent used in the cyclization condensation reaction performed in advance before the lactone cyclization condensation process using the devolatilization process may be the solvent used in the polymerization process or another solvent.

  The other solvent used in the cyclization condensation reaction performed in advance is not particularly limited, and examples thereof include aromatic hydrocarbons such as toluene, xylene, and ethylbenzene; ketones such as methyl ethyl ketone and methyl isobutyl ketone; Chloroform, DMSO, tetrahydrofuran; and the like. However, it is more preferable to use the same type of solvent as that used in the polymerization step.

  As the catalyst to be added in the above method (i), esterification catalyst or transesterification catalyst such as p-toluenesulfonic acid generally used as a catalyst for cyclization condensation reaction, basic compound, organic carboxylate, carbonate Etc. may be used. However, in one embodiment of the present invention, it is preferable to use the aforementioned organic phosphorus compound.

  The addition timing of the catalyst is not particularly limited, and may be added at the initial stage of the cyclization condensation reaction, may be added during the reaction, or may be added in both of them. The amount of the catalyst to be added is not particularly limited, but is preferably in the range of 0.001 to 5% by mass, more preferably 0.01 to 2.5% by mass with respect to the mass of the polymer. Within the range, more preferably within the range of 0.01 to 0.1% by mass, and particularly preferably within the range of 0.05 to 0.5% by mass.

  The heating temperature and heating time in method (i) are not particularly limited, but the heating temperature is preferably room temperature or higher, more preferably 50 ° C. or higher, and the heating time is preferably 1 to 20 Within a time range, more preferably within a range of 2 to 10 hours. If the heating temperature is low or the heating time is short, the reaction rate of the cyclization condensation reaction may be reduced. Further, if the heating temperature is high or the heating time is long, the lactone ring structure-containing polymer may be colored or decomposed.

  Examples of the method (ii) include a method of heating the polymerization reaction mixture obtained in the polymerization step as it is using a pressure-resistant kettle reactor or the like. The heating temperature is preferably 100 ° C. or higher, more preferably 150 ° C. or higher. The heating time is preferably in the range of 1 to 20 hours, more preferably in the range of 2 to 10 hours. If the heating temperature is low or the heating time is short, the reaction rate of the cyclization condensation reaction may be reduced. Further, if the heating temperature is high or the heating time is long, the lactone ring structure-containing polymer may be colored or decomposed.

  Both the above methods (i) and (ii) can be performed under pressure depending on conditions (the above method (iii)). In the cyclization condensation reaction carried out in advance, there is no problem even if a part of the solvent volatilizes spontaneously during the reaction.

  At the end of the cyclization condensation reaction carried out in advance, that is, immediately before the start of the devolatilization step, the mass reduction rate between 150 and 300 ° C. in the dynamic TG measurement is preferably 2% or less. It is more preferably 5% or less, and further preferably 1% or less. If the mass reduction rate is higher than 2%, even if the lactone cyclization condensation step is used in combination with the devolatilization step, the reaction rate of the cyclization condensation reaction does not rise to a sufficiently high level, and the resulting lactone ring structure There exists a possibility that the physical property of a containing polymer may fall.

  In the lactone cyclization condensation process (including both the process using the devolatilization process and the process not using the devolatilization process), another thermoplastic resin coexists in the mixture containing the polymer and the solvent. You may let them. The other thermoplastic resin is preferably a thermoplastic resin that is thermodynamically compatible with the lactone ring structure-containing polymer. Examples of the other thermoplastic resin include a copolymer containing a vinyl cyanide monomer unit and an aromatic vinyl monomer unit. Specific examples include acrylonitrile-styrene copolymers, polyvinyl chloride resins, and polymers containing 50% by mass or more of methacrylic acid esters.

  Among these other thermoplastic resins, an acrylonitrile-styrene copolymer is most preferable because it is most compatible and a transparent molded product can be obtained without impairing heat resistance. Whether the lactone ring structure-containing polymer and other thermoplastic resins are thermodynamically compatible is confirmed by measuring the glass transition temperature of the thermoplastic resin composition obtained by mixing the two. can do. Specifically, when only one point of the glass transition temperature of the thermoplastic resin composition measured by a differential scanning calorimeter is observed, it can be said that the two are thermodynamically compatible.

  In the case of using an acrylonitrile-styrene copolymer as another thermoplastic resin, as a method for polymerizing a lactone ring structure-containing polymer and an acrylonitrile-styrene copolymer, an emulsion polymerization method, a suspension polymerization method, a solution Examples thereof include a polymerization method and a bulk polymerization method. Among these polymerization methods, a solution polymerization method and a bulk polymerization method are more preferable from the viewpoints of transparency and optical performance of the obtained optical film.

  (i) The hydroxyl group and ester group present in the molecular chain of the polymer obtained in the polymerization step are subjected to a cyclization condensation reaction, and the reaction rate of the cyclization condensation reaction is increased to some extent in advance. ii) In the form of performing the lactone cyclization condensation step combined with the devolatilization step, the polymer obtained by the cyclization condensation reaction performed in advance (a part of the hydroxyl group and ester group present in the molecular chain undergoes cyclization condensation reaction). You may start the lactone cyclization condensation process which used the devolatilization process together, without isolate | separating a polymer) and a solvent. In addition, if necessary, other treatment (polymer obtained in advance by cyclization condensation reaction (polymer obtained by cyclization condensation reaction of a part of hydroxyl groups and ester groups present in the molecular chain) and solvent After the separation, a lactone cyclization condensation process using a devolatilization process may be started after another solvent is added.

  The devolatilization process does not need to be completed at the same time as the lactone cyclization condensation process, and may be completed after a lapse of time from the completion of the lactone cyclization condensation process. That is, the devolatilization process may be completed before the lactone cyclization condensation process or may be completed after.

  As described above, in the lactone cyclization condensation step, a hydroxyl group and an ester group present in the molecular chain of the polymer undergo a cyclization condensation reaction to cause a dealcoholization reaction, which is a kind of transesterification, thereby causing heavy polymerization. A lactone ring structure is formed in the molecular chain of the polymer (in the main skeleton of the polymer).

[Method for producing thermoplastic resin composition]
The method for producing the thermoplastic resin composition is not particularly limited. By uniformly mixing the (meth) acrylic resin and the ultraviolet absorber, the thermoplastic resin composition in one embodiment of the present invention is obtained.

  The other polymer or additive may be mixed when the (meth) acrylic resin and the ultraviolet absorber are mixed, or previously mixed with the (meth) acrylic resin and / or the ultraviolet absorber. May be mixed with the other. The mixing method is not particularly limited.

[Method for forming (meth) acrylic film]
The method for forming the (meth) acrylic film is not particularly limited, and general methods (for example, touch roll film formation and open film formation) can be used, but the contact angle with pure water is reduced. And from a viewpoint of suppressing bleed-out, it is preferable to use touch roll film formation.

  Touch roll film formation is, for example, a film of a predetermined size and thickness obtained by sandwiching a melt of a thermoplastic resin composition discharged continuously from a die in a film shape between a touch roll and a cast roll. This is a method of continuously forming a film. More specifically, touch roll film formation is, for example, by discharging the melt from a die between a touch roll and a cast roll, sandwiching between the touch roll and the cast roll, forming, and then cooling and solidifying. This is a method of continuously forming a film.

  By touch roll film formation, the contact angle with pure water can be reduced, and as a result, the wettability of the (meth) acrylic film is improved. By improving the wettability, uniform application of the water-based primer becomes possible.

  In touch roll film formation, the temperature of the melt at the die outlet is preferably adjusted to satisfy “50 ≦ Td−Tp” (thermal decomposition start temperature: Td, melt temperature: Tp). Bleed out can be suppressed.

  The temperature of the melt is the highest of the temperatures measured at multiple locations by contacting the melt immediately after being discharged from a die such as a T die (within 30 mm from the die lip) with a needle-shaped or rod-shaped thermocouple. Refers to temperature.

  Although there is no restriction | limiting in particular in the upper limit of "Td-Tp", it is more preferable that it is 90 degrees C or less. Therefore, “Td−Tp” is more preferably 50 ° C. or more and 90 ° C. or less, further preferably 55 ° C. or more and 85 ° C. or less, and particularly preferably 60 ° C. or more and 80 ° C. or less. preferable. When “Td−Tp” is less than 50 ° C., the ultraviolet absorber contained in the thermoplastic resin composition is thermally decomposed. When “Td−Tp” exceeds 90 ° C., the viscosity of the melt is high and the flow in the die becomes poor. Therefore, the melt does not sufficiently flow to the end portion, and the film thickness profile may be deteriorated.

(Die)
The die is provided at the outlet of a melting apparatus that melts the thermoplastic resin composition. And it is comprised so that the melt of a thermoplastic resin composition may be made into a film form, and it may discharge continuously on a touch roll or a cast roll. The material of the die is preferably a metal, and more preferably stainless steel. The size and number of dies may be appropriately set according to the amount of melt to be discharged, and are not particularly limited.

  The temperature of the die is preferably in the same range as the temperature of the apparatus used for film formation. The relationship between the thermal decomposition temperature Td (° C.) of the ultraviolet absorber contained in the thermoplastic resin composition and the temperature Tp (° C.) of the melt at the outlet of the die is expressed by the formula “50 ≦ Td−Tp. It is more preferable to set so as to satisfy “ In addition, the said melting apparatus is comprised so that a thermoplastic resin composition can be fuse | melted so that the said formula may be satisfy | filled, and a melt more than temperature Tp (degreeC) can be prepared.

(Touch roll and cast roll)
The touch roll and the cast roll are installed in parallel to face each other. There may be a plurality of touch rolls and cast rolls. The surface of the touch roll and cast roll is particularly preferably mirror-finished.

  The touch roll is preferably formed from an elastic material. The material of the touch roll and cast roll is preferably SCM steel or stainless steel such as SUS. Furthermore, as a touch roll and a cast roll, a material obtained by plating the above steel or stainless steel with chromium, nickel, titanium or the like; TiN, TiAlN, TiCN, CrN, or DLC by PVD (Physical Vapor Deposition) method or the like It is also possible to use a material formed with a surface coating such as (diamond-like carbon); a material obtained by spraying tungsten carbide or other ceramic; and a material obtained by nitriding the surface of the steel or stainless steel. Is preferred.

  The touch pressure, which is a value obtained by dividing the pressing force of the touch roll relative to the cast roll by the contact area between the film and the touch roll, is preferably in the range of 0.1 MPa to 10 MPa, and in the range of 0.3 MPa to 8 MPa. It is more preferable that it is in a range of 0.5 MPa to 5 MPa.

  The touch roll and the cast roll have an arithmetic average height (Ra) of the surface of preferably 100 nm or less, more preferably 50 nm or less, and further preferably 25 nm or less. Thereby, the film which has moderate unevenness | corrugation on the surface can be formed. If the material of the surface of the touch roll and cast roll is metal, it is easy to make Ra of these rolls 100 nm or less.

  The thickness, length, temperature, and the like of the touch roll and cast roll may be appropriately set according to the desired size and thickness of the (meth) acrylic film, and are not particularly limited. However, in order to gradually cool (cool) the melt, it is more preferable that there are a plurality (more specifically, 2 to 6) of the cast rolls.

  And, for example, when forming a film by gradually cooling the melt using two or more cast rolls, the cast roll adjacent to the downstream side rather than the cast roll on the side closer to the die (upstream side) The temperature is preferably lower than 0 ° C. and lower than 20 ° C., more preferably 1 ° C. to 18 ° C., more preferably 2 ° C. to 15 ° C. lower than the temperature of the upstream cast roll. Is more preferable. Thereby, the physical property of both surfaces of the (meth) acrylic-type film obtained can be made more uniform, and the residual distortion in the said (meth) acrylic-type film becomes easy to be eliminated. Therefore, the dimensional stability of the (meth) acrylic film against humidity and heat can be improved. Note that the temperature of the cast roll closest to the die (the most upstream side) may be set as appropriate according to the temperature of the melt.

  The temperature of the touch roll is preferably in the range of Tg−80 ° C. to Tg + 10 ° C., based on the glass transition temperature (Tg) of the thermoplastic resin composition, and is in the range of Tg−70 ° C. to Tg + 5 ° C. It is more preferable that it is in the range of Tg-60 ° C to Tg.

  The temperature control of the touch roll and the cast roll can be performed, for example, by circulating a heat medium (liquid or gas) whose temperature is adjusted inside these rolls.

(Film forming speed)
The film forming speed of the melt may be appropriately set according to the desired size and thickness of the (meth) acrylic film, and is not particularly limited. The film forming speed is preferably in the range of 2 m / min to 50 m / min, more preferably in the range of 2 m / min to 40 m / min, and in the range of 3 m / min to 35 m / min. More preferably it is. By setting the film forming speed within the above range, the melt is pulled by the touch roll and the cast roll at the exit of the die, the expansion of the melt is suppressed, and the melt is rubbed against the exit of the die. It is suppressed. Therefore, the unevenness | corrugation of the surface of the (meth) acrylic-type film obtained can be controlled to a preferable range. Also, by setting the film forming speed within the above range, the residence time of the melt in the die can be kept short, so the number of foreign matters (gels and contaminants) contained in the melt can be reduced. . When the film forming speed exceeds 50 m / min, the melt flow at the outlet of the die is disturbed, and the uniformity of the film may be lowered.

Even when a UV absorber having a low thermal decomposition temperature is used by forming a heat-resistant (meth) acrylic resin having a glass transition temperature of 108 ° C. or more into a touch roll, the b ^* value is A (meth) acrylic film having good optical properties can be produced which is low and good, has no transfer of contaminants from the rolls (touch roll and cast roll) during film formation.

Here, ^{b *} value and is the index in ^{b *} color system defined in JIS Z 8729, ^{b *} values represent color. The b ^* value means that the closer to 0, the closer to an achromatic color.

  The relationship between the thermal decomposition temperature Td (° C.) of the ultraviolet absorber contained in the thermoplastic resin composition and the temperature Tp (° C.) of the melt at the outlet of the die is expressed by the formula “50 ≦ Td−Tp”. If the melt is discharged from the die so as to satisfy, the above-described effect can be further increased.

  In addition, you may trim the both ends of the (meth) acrylic-type film obtained by touch roll film forming as needed. The (meth) acrylic film cut off by trimming can be reused as a raw material if it is crushed.

(Winding and stretching)
The (meth) acrylic film continuously produced by touch roll film formation is peeled off from the cast roll, passed through a nip roll, etc., and then wound around a core material to form a roll-shaped (meth) acrylic film. . The winding speed of the (meth) acrylic film is not particularly limited, but is preferably in the range of 1 m / min to 100 m / min, and preferably in the range of 2 m / min to 80 m / min. Is more preferable, and it is still more preferable that it is in the range of 3 m / min to 70 m / min. The winding tension of the (meth) acrylic film is not particularly limited, but is preferably in the range of 1 N / m width to 500 N / width, and in the range of 1 N / m width to 300 N / width. More preferably, it is within.

  Before winding up the (meth) acrylic film, a protective film made of polyethylene, polypropylene, polyester, or the like may be attached to one side or both sides of the (meth) acrylic film. The thickness of the protective film is not particularly limited, but is preferably in the range of 5 μm to 100 μm, and more preferably in the range of 10 μm to 50 μm.

  The (meth) acrylic film continuously produced by touch roll film formation is preferably subjected to longitudinal stretching and / or lateral stretching (hereinafter, both longitudinal stretching is referred to as “MD stretching” and lateral stretching is referred to as “TD stretching”. write). The MD stretching and / or TD stretching may be performed in combination with the shrinkage relaxation treatment. The (meth) acrylic film according to the present invention is more preferably biaxially stretched (MD stretching and TD stretching). Note that MD is an abbreviation for Machine Direction and is synonymous with “longitudinal direction” and “vertical direction”. TD is an abbreviation for Transverse Direction and is synonymous with “width direction” and “lateral direction”.

  Although the specific method of MD extending | stretching is not specifically limited, For example, methods, such as oven longitudinal stretching and roll longitudinal stretching, are mentioned.

  Oven longitudinal stretching is a method in which an original film is stretched in the longitudinal direction by providing a peripheral speed difference between a transport roll on the entrance side of the oven and a transport roll on the exit side. The oven is configured so that the original film can be heated to a temperature at which it can be stretched. According to oven longitudinal stretching, depending on the stretching conditions, a heat treatment effect can be imparted to the stretched film.

  The stretching temperature in the oven longitudinal stretching is preferably in the range of Tg-10 ° C to Tg + 50 ° C, based on the glass transition temperature (Tg) of the original film, and in the range of Tg-5 ° C to Tg + 40 ° C. Is more preferable, and it is more preferable that it is in the range of Tg ° C. to Tg + 30 ° C. If it is stretched at a temperature lower than Tg-10 ° C, the original film may be broken. When the film is stretched at a temperature higher than Tg + 50 ° C., the sag of the original film becomes large, so that the original film and the apparatus may be rubbed or the original film may be broken.

  Roll longitudinal stretching is a method in which an original film is heated to a stretching temperature while continuously contacting many heating rolls and stretched by a nip roll provided in a stretching section. Thereafter, the stretched film is cooled by a cooling roll. An auxiliary heating device may be provided in the stretching section in order to stabilize the stretching temperature. Roll longitudinal stretching can be carried out using a roll longitudinal stretching machine.

  The temperature of the heating roll in the roll longitudinal stretching machine refers to the set temperature of the heating roll. The stretching temperature and stretching ratio of the original film can be appropriately adjusted using as an index the mechanical strength, surface property and thickness accuracy of the film obtained after longitudinal stretching. In stretching, the original film is preferably heated to a range of Tg-10 ° C. to Tg + 20 ° C. with a heating roll based on the glass transition temperature (Tg) of the film. Furthermore, it is more preferable to heat to the range of Tg ° C. to Tg + 30 ° C. by an auxiliary heating device provided in the stretching section. When the heating of the original film by the heating roll is lower than Tg-10 ° C., it tends to cause problems in processes such as tearing or cracking of the original film. When the heating of the original film by the heating roll is higher than Tg + 30 ° C., it is difficult to improve the mechanical properties such as elongation, tensile strength and flexibility of the finally obtained (meth) acrylic film. Subsequent workability may deteriorate.

  The total number of heating rolls is preferably 5 or more. When the number of heating rolls is less than 5, the heating effect is reduced, and the original film cannot be heated sufficiently. Instead of reducing the total number of heating rolls to less than 5, the method of increasing the roll diameter of the heating rolls to increase the heating effect cannot sufficiently stretch the original film that has been thermally expanded due to heating, causing wrinkles. This is not preferable because it is easy to break and wrinkles are easily generated.

  As the auxiliary heating device provided in the stretching section, a known device may be mentioned. Specifically, for example, at least one selected from an IR heater, a ceramic heater, and a hot air heater is preferable.

  The stretching speed when performing MD stretching may be appropriately set according to the desired properties of the (meth) acrylic film and is not particularly limited, but is preferably within the range of 10 to 20000% / min. More preferably within the range of 100 to 10000% / min. If the stretching speed is slower than 10% / min, it takes time to obtain a sufficient stretching ratio, and the production cost increases. If the stretching speed is faster than 20000% / min, the film may be broken.

  The draw ratio when MD stretching is performed may be appropriately set according to the desired properties of the (meth) acrylic film, and is not particularly limited, but is preferably within the range of 10 to 300%. More preferably, it is in the range of 15 to 300%, and further preferably in the range of 20 to 200%. The stretch ratio is defined by “stretch ratio (%) = 100 × {(length after stretching) − (length before stretching)} / (length before stretching)”.

  Although the stretching temperature when performing TD stretching is not particularly limited, it is preferably within the range of Tg−5 ° C. to Tg + 30 ° C. based on the glass transition temperature (Tg) of the original film. It is more preferably within the range of Tg + 30 ° C., and further preferably within the range of Tg to Tg + 20 ° C. If the stretching temperature is less than Tg-5 ° C, the film may be broken before stretching. When the stretching temperature exceeds Tg + 30 ° C., the relaxation of the molecular chain is increased and the molecules may not be easily oriented.

  The stretching speed when performing TD stretching may be appropriately set according to the desired properties of the (meth) acrylic film and is not particularly limited, but is preferably within the range of 10 to 20000% / min. More preferably within the range of 100 to 10000% / min. If the stretching speed is slower than 10% / min, it takes time to obtain a sufficient stretching ratio, and the production cost increases. If the stretching speed is faster than 20000% / min, the film may be broken.

  What is necessary is just to set suitably the draw ratio at the time of performing TD extending | stretching according to the characteristic of the desired (meth) acrylic-type film, Although it does not specifically limit, It is preferable to exist in the range of 10 to 300%. More preferably, it is in the range of 15 to 300%, and further preferably in the range of 20 to 200%.

  The (meth) acrylic film may be heat-treated before MD stretching and / or TD stretching, or may be heat-treated after MD stretching and / or TD stretching.

  Although the (meth) acrylic film according to the present invention is not particularly limited, the ratio of the draw ratio in the machine direction and the draw ratio in the transverse direction (stretch ratio of MD stretch / stretch ratio of TD stretch) is It is preferably within the range of 0.40 to 1.50, more preferably within the range of 0.45 to 1.40, and even more preferably within the range of 0.50 to 1.30.

  The manufacturing method of the (meth) acrylic film in one embodiment of the present invention may be a manufacturing method including a step of applying the above-described aqueous primer on the above-described (meth) acrylic film. A method for applying the water-based primer is not particularly limited, and a coating layer forming method usually used in the art such as bar coating, wire coating, or spin coating can be used. Moreover, the film of the aspect by which the water-system primer was apply | coated on the (meth) acrylic-type film in one Embodiment of this invention mentioned above in this invention may be included.

<3. Characteristics and applications of (meth) acrylic films>
Below, the characteristic of a (meth) acrylic-type film and the use of a (meth) acrylic-type film are described.

[Characteristics of (meth) acrylic film]
The (meth) acrylic film in one embodiment of the present invention is a (meth) acrylic film made of the above-described thermoplastic resin composition, and the contact angle with pure water is 76 ° or less. The (meth) acrylic film in one embodiment of the present invention is a (meth) acrylic film made of the above-described thermoplastic resin composition, and a contact angle with pure water is 75 ° or less, 73 ° or less, or 71 degrees or less.

  If the contact angle with pure water is 76 ° or less, the water-based primer can be uniformly applied to the (meth) acrylic film. In the present embodiment, the “contact angle” is a value measured according to JIS R3257: 1999 using a contact angle measuring instrument (“FACE contact angle meter CA-X” manufactured by Kyowa Interface Chemical Co., Ltd.). . Further, the lower limit value of the contact angle with pure water is not particularly limited, but may be 60 ° or more, 63 ° or more, 65 ° or more, or 67 ° or more.

  Various functional coating layers may be formed on the surface of the (meth) acrylic film according to the embodiment of the present invention as necessary. Functional coating layers include, for example, antistatic layers, adhesive layers, adhesive layers, easy adhesion layers, antiglare (non-glare) layers, antifouling layers such as photocatalyst layers, antireflection layers, hard coat layers, and UV shielding layers. A layer, a heat ray shielding layer, an electromagnetic wave shielding layer, or a gas barrier layer.

  In particular, when a hydrophilic coating layer is formed on the surface of a (meth) acrylic film, the wettability of the film is improved and the contact angle with pure water can be reduced. Thereby, a water-system primer can be more uniformly apply | coated to a (meth) acrylic-type film. However, the (meth) acrylic film in one embodiment of the present invention can be sufficiently improved in wettability without forming a hydrophilic coating layer. Therefore, it is preferable to omit forming a hydrophilic coating layer on the surface of the (meth) acrylic film from the viewpoint of reducing the production cost of the film by simplifying the production process of the film. .

  The thickness of the (meth) acrylic film in one embodiment of the present invention is preferably 20 μm or more and 100 μm or less, more preferably 80 μm or less, and further preferably 60 μm or less.

  The thickness of the (meth) acrylic film was measured using a Digimatic Micrometer (manufactured by Mitutoyo Corporation). The sample for measuring and evaluating the physical properties of the (meth) acrylic film including the physical properties indicating the evaluation method was obtained from the center in the width direction of the (meth) acrylic film.

  The (meth) acrylic film in one embodiment of the present invention has a 400 nm transmittance of 85% or more (for example, 87% or more, 90% or more, 92% or more, when the transmittance of 500 nm is 100%, 95% or more or 97% or more) and the transmittance at 380 nm is 35% or less (for example, 30% or less, 25% or less, 20% or less, 15% or less, 10% or less, or 5% or less). Preferably there is.

  The (meth) acrylic film in one embodiment of the present invention has a 400 nm transmittance of 85% or more (for example, 87% or more, for example) when the film thickness is 40 μm and the 500 nm transmittance is 100%. 90% or more, 92% or more, 95% or more, or 97% or more) and the transmittance of 380 nm is 35% or less (for example, 30% or less, 25% or less, 20% or less, 15% or less, 10% Or 5% or less). In this case, the film thickness is not limited to 40 μm, and may be a desired film thickness (for example, an arbitrary thickness in the range of 1 μm to 100 μm).

  When the transmittance is in the above-described range, it is possible to obtain a (meth) acrylic film that has improved weather resistance and can be applied uniformly with a water-based primer.

[Characteristics of (meth) acrylic film containing lactone ring structure-containing polymer]
When the (meth) acrylic film in one embodiment of the present invention contains a lactone ring structure-containing polymer, the weight average molecular weight of the lactone ring structure-containing polymer is preferably 1,000 or more and 2,000,000 or less, More preferably, it is 5,000 or more and 1,000,000 or less, More preferably, it is 10,000 or more and 500,000 or less, Especially preferably, it is 50,000 or more and 500,000 or less.

  The lactone ring structure-containing polymer preferably has a mass reduction rate of 150% to 300 ° C. in dynamic TG measurement of 1% or less, more preferably 0.5% or less. More preferably, it is 3% or less.

  Since the above-mentioned lactone ring structure-containing polymer has a high reaction rate of the cyclization condensation reaction, it is possible to avoid the disadvantage that bubbles and silver streaks enter the molded product after molding. Furthermore, since the reaction rate of the cyclization condensation reaction is high, the lactone ring structure-containing polymer is sufficiently introduced into the lactone ring structure-containing polymer, so that the obtained lactone ring structure-containing polymer has sufficiently high heat resistance. is doing.

  The lactone ring structure-containing polymer has a 5% mass reduction temperature in thermogravimetric analysis (TG) of preferably 280 ° C. or higher, more preferably 290 ° C. or higher, and further preferably 300 ° C. or higher. . The 5% mass reduction temperature in thermogravimetric analysis (TG) is an index of thermal stability. When the temperature is less than 280 ° C., the obtained lactone ring structure-containing polymer has sufficient thermal stability. There is a possibility that it cannot be demonstrated.

  In the lactone ring structure-containing polymer, the total amount of residual volatile components contained in the lactone ring structure-containing polymer is preferably 5,000 ppm or less, and more preferably 2,000 ppm or less. If the total amount of residual volatile components is more than 5,000 ppm, the lactone ring structure-containing polymer may be colored or foamed due to alteration during molding, or molding defects such as silver streaks may occur.

  The lactone ring structure-containing polymer has a total light transmittance of a molded product obtained by injection molding, measured by a method according to ASTM-D-1003, preferably 85% or more, more preferably 88% or more, Preferably it is 90% or more. The total light transmittance is a measure of transparency. If the transmittance is less than 85%, the transparency is lowered, and there is a possibility that it cannot be used for the intended intended use.

[Use of (meth) acrylic film]
The use of the (meth) acrylic film according to an embodiment of the present invention is not particularly limited. The (meth) acrylic film according to an embodiment of the present invention is suitable for the following uses.

  The application is, for example, an optical protective film (specifically, a protective film for substrates of various optical disks (VD, CD, DVD, MD, LD, etc.)) or a polarizing plate provided in an image display device such as an LCD. It is a polarizer protective film to be used. In addition, the present invention as an optical film such as a viewing angle compensation film, a light diffusion film, a reflection film, an antireflection film, an antiglare film, a brightness enhancement film, a conductive film for a touch panel, a retardation film, or a light conversion film. The (meth) acrylic film which concerns on one Embodiment can be used. Especially, it is suitable for use as a polarizer protective film.

  At this time, the optical characteristics can be controlled by using the (meth) acrylic film according to an embodiment of the present invention by being laminated with the same kind of optical material and / or different kind of optical material. Although it does not specifically limit as an optical material laminated | stacked in this case, For example, a polarizing plate, the extending | stretching orientation film made from a polycarbonate, the extending | stretching orientation film made from cyclic polyolefin, etc. are mentioned.

  That is, an optical film using a (meth) acrylic film according to an embodiment of the present invention, a polarizer protective film using the optical film, a polarizing plate provided with the polarizer protective film, and the polarizing plate The provided image display device is also included in the present invention.

<4. Water-based primer>
Since the (meth) acrylic film in one embodiment of the present invention has a contact angle with pure water of 76 ° or less, a water-based primer can be uniformly applied to the (meth) acrylic film. Hereinafter, the water-based primer will be described.

  The water-based primer is a primer that does not use an organic solvent mainly composed of a water-soluble resin or a water-dispersible resin or uses a small amount thereof. The water-based primer does not damage the (meth) acrylic film, has low fire hazard and environmental impact, has excellent workability, and does not require an expensive solvent as a diluent. Have.

  As the water-based primer, a hydrophilic resin can be used, and examples thereof include urethane resin, hydroxyl group-containing acrylic resin, amino resin, epoxy resin, phenol resin, polyester, alkyd resin, styrene maleic acid resin, and silicon resin. It is done. A plurality of them may be used in combination. Of these, urethane resin is most preferable.

  The urethane resin is not particularly limited, and examples thereof include acrylic urethane resin, polyester resin, polyether resin, urethane diol, and polycarbonate resin. Typically, the urethane resin is obtained by reacting a polyol and a polyisocyanate. Resin. Any polyol having two or more hydroxyl groups in the molecule can be adopted as the polyol. The polyol is, for example, a polyacryl polyol, a polyester polyol, or a polyether polyol. Two or more polyols may be combined.

  The polyacryl polyol is typically a copolymer of a (meth) acrylic acid ester monomer and a monomer having a hydroxyl group. The (meth) acrylic acid ester monomer is, for example, methyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, or cyclohexyl (meth) acrylate. Examples of the monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, (Meth) acrylic acid hydroxyalkyl esters such as (meth) acrylic acid 4-hydroxybutyl or (meth) acrylic acid 2-hydroxypentyl; (meth) acrylic acid monoesters of polyhydric alcohols such as glycerin or trimethylolpropane; N-methylol (meth) acrylamide.

  Examples of the polyisocyanate include tetramethylene diisocyanate, dodecamethylene diisocyanate, 1,4-butane diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, Aliphatic diisocyanates such as 2-methylpentane-1,5-diisocyanate or 3-methylpentane-1,5-diisocyanate; isophorone diisocyanate, hydrogenated xylylene diisocyanate, 4,4'-cyclohexylmethane diisocyanate, 1,4- Such as cyclohexane diisocyanate, methylcyclohexylene diisocyanate, or 1,3-bis (isocyanatomethyl) cyclohexane Cyclic diisocyanate; tolylene diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyl diisocyanate Aromatic diisocyanates such as 1,5-naphthylene diisocyanate, xylylene diisocyanate, 1,3-phenylene diisocyanate, or 1,4-phenylene diisocyanate; dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate or α, α, α, α An araliphatic diisocyanate such as tetramethylxylylene diisocyanate.

  Examples of the hydroxyl group-containing acrylic resin include, but are not limited to, vinyl-modified alkyd, silicon acrylic resin, styrene acrylic resin, or vinyl-modified epoxy ester resin.

  Examples of suitable monomer compositions constituting these hydroxyl group-containing acrylic resins include hydroxyl group-containing acrylic acid hydroxy esters such as 2-hydroxyethyl acrylate and 4-hydroxybutyl acrylate; 2-hydroxyethyl methacrylate, methacryl Methacrylic acid hydroxy ester containing a hydroxyl group, such as 4-hydroxybutyl acid; and, if necessary, acrylic acid; methyl acrylate, butyl acrylate, isobutyl acrylate, acrylic acid acrylic acid esters such as t-butyl, 2-ethylhexyl acrylate, lauryl acrylate, isobornyl acrylate; methacrylic acid; methyl methacrylate, butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, 2-methacrylic acid 2- It includes compositions comprising at least one of the like; ethylenically unsaturated monomer having an aromatic ring such as styrene; hexyl, lauryl methacrylate, methacrylic acid and the like isobornyl. The composition of the monomer composition may be appropriately adjusted according to various physical properties required for the hydroxyl group-containing acrylic resin.

  Examples of amino resins include, but are not limited to, urea resins and aqueous melamine resins.

  The epoxy resin is not particularly limited. For example, bisphenol type epoxy resin, bisphenol A novolac type epoxy resin, biphenyl type epoxy resin, phenol novolac type epoxy resin, alkylphenol novolac type epoxy resin, polyglycol type epoxy resin, cyclic aliphatic Epoxy resin, dicyclopentadiene type epoxy resin, biphenyl type epoxy resin, phenoxy type epoxy resin, cresol novolac type epoxy resin, glycidylamine type epoxy resin, amine type epoxy resin, flexible epoxy resin, trisphenolmethane type epoxy resin, Naphthalene-type epoxy resin, urethane-modified epoxy resin, rubber-modified epoxy resin, heterocyclic-containing epoxy resin, chelate-modified epoxy resin, epoxy-modified polysiloxane Epoxy resins such as emissions; these halogenated epoxy resins; and crystalline epoxy resin having a melting point thereof.

  Phenol resins include, but are not limited to, phenol novolac resins, cresol novolac resins, and naphthalene type phenol resins.

  The polyester includes anionic, cationic, and nonionic polyesters, any of which can be used.

  Examples of the silicon resin include, but are not limited to, silicon acrylic resin and water-based epoxy silicon.

  Examples of the alkyd resin include, but are not limited to, a polyester alkyd resin.

[Measurement methods for physical properties, etc.]
(Measurement of contact angle with pure water)
It measured based on JISR3257: 1999 using the contact angle measuring device ("FACE contact angle meter CA-X" by Kyowa Interface Chemical Co., Ltd.). The contact angle between pure water 30 seconds after the dropping and the (meth) acrylic film was measured 5 times, and the average value of the 3 measurements except for the highest value and the lowest value was taken as the contact angle.

(Light transmittance at 380 nm and 400 nm)
Based on the provisions of JIS K7361: 1997, UV-1600PC manufactured by Shimadzu Corporation was used to measure the light transmittance at 380 nm and 400 nm for the stretched film.

(Coating unevenness evaluation)
The stretched film is cut into a size of 50 mm × 100 mm, water-based urethane resin (Daiichi Kogyo Seiyaku: Superflex (registered trademark) 210) as the main agent, and oxazoline group-containing water-soluble polymer (manufactured by Nippon Shokubai Co., Ltd.) as the cross-linking agent. Epocross (registered trademark) WS-700), and an aqueous solution mixed with silica fine particles (manufactured by Nippon Shokubai Co., Ltd .: Seahoster (registered trademark) KE-W30) as an AB agent was coated on the film surface using a bar coater, It was dried and cured at 100 ° C. for 10 minutes.

  About the obtained coating film, IR spectrum was obtained on the following measurement conditions about the film edge part and film center part using iS10 by ThermoSCIENTIFIC. An example of the obtained IR spectrum is shown in FIG.

In addition, in the edge part, the measurement was performed in a total of 10 points | pieces, 5 points | pieces at a 2 mm location from the cut | disconnected film longitudinal direction both ends. In the central part, five points were measured at equal intervals from 15 mm to 20 mm from both ends in the longitudinal direction of the cut film, and the measurement was made at a total of 10 points.
Measurement conditions Measurement method: ATR method Measurement region: 650-4000 cm ⁻¹
Resolution: 4cm ^-1
Accumulation count: 32 times Ratio of peak intensity between peak (a) of about 1725 cm ⁻¹ attributed to the substrate film and peak (b) of about 730 cm ⁻¹ attributed to the primer in the obtained IR spectrum (b / About a), the location where the value of the peak intensity ratio at the end portion was larger than the minimum value of the peak strength ratio value at the central portion was determined as a location without coating unevenness. Of the 10 places where there was no coating unevenness, 9 or 10 places were evaluated as “◎”, 6 to 8 places were evaluated as “◯”, and 5 or less places were evaluated as “X”.

[Example 1]
(Manufacture of (meth) acrylic resin composition)
In a reaction vessel equipped with a stirrer, a temperature sensor, a cooling condenser and a nitrogen introducing tube, 83.5 parts of methyl methacrylate (MMA), 12 parts of methyl 2- (hydroxymethyl) acrylate (MHMA), 90.4 parts of toluene , 0.05 part of tris (2,4-jettery-butylphenyl) phosphite (manufactured by ADEKA: Adeka Stub (registered trademark) 2112) and 0.07 part of n-dodecyl mercaptan were charged with nitrogen, The temperature was raised to 105 ° C.

  When the reflux accompanying the temperature increase started, 0.09 part of t-amylperoxyisononanoate (Arkema Yoshitomi Co., Ltd .: Luperox (registered trademark) 570) was added as a polymerization initiator, and the above-mentioned t-amylper While 0.18 parts of oxyisononanoate and 4.5 parts of styrene were added dropwise over 2 hours, solution polymerization was allowed to proceed under reflux at about 105 to 110 ° C., and after completion of the addition, aging was continued for 4 hours at the same temperature. Went.

  Next, 0.075 part of stearyl phosphate (SC Organic Chemical Co., Ltd .: Phoslex A-18) is added to the obtained polymerization solution as a catalyst for the cyclization condensation reaction (cyclization catalyst), and about 90 to 110 is added. The cyclization condensation reaction for forming a lactone ring structure was allowed to proceed for 2 hours under reflux at ° C. Furthermore, the obtained polymerization solution was passed through a multitubular heat exchanger heated to 240 ° C. to complete the cyclization condensation reaction.

  Thereafter, the barrel temperature is 250 ° C., one rear vent, four fore vents (referred to as first, second, third, and fourth vents from the upstream side) and between the third vent and the fourth vent. Equipped with a side feeder, a leaf disk type polymer filter (filtration accuracy 5 μm) at the tip, and a vent type screw twin screw extruder (L / D = 52.5) with a diameter of 47 mm, 35.1 parts / hour It was introduced at a processing speed of (resin amount conversion). At that time, ion exchange water was added at a rate of 0.54 parts / hour from the front of the second vent and at a rate of 0.18 parts / hour from the front of the third and fourth vents. Further, from the side feeder, an ultraviolet absorber (Kemipro Kasei Co., Ltd .: KEMISORB (registered trademark) 279RC, weight reduction start temperature Td (° C.) is 345 ° C., molecular weight 659) is charged at a rate of 0.36 parts / hour. I put it in. At this time, the rear vent was reduced to 80.0 kPa, the first vent was reduced to 26.7 kPa, the second to fourth vents were reduced to 2.6 kPa, and devolatilization was performed at a throughput of the outlet resin of 35.5 kg / hour.

  After completion of the devolatilization, the resin composition in the hot melt state remaining in the extruder was discharged while being filtered from the tip of the extruder through a polymer filter. After the resin composition passed through a die provided in the extruder, it was filtered with a filter having a pore diameter of 1 μm (manufactured by Organo Corporation: Micropore filter 1EU). The strand is cooled by a water tank filled with cooling water kept at a temperature within the range of 30 ± 10 ° C., and introduced into a cutting machine (pelletizer), whereby (meth) acrylic resin composition (A-1) is obtained. Obtained.

(Film production)
A film was produced from the obtained (meth) acrylic resin composition (A-1) by performing touch roll film formation.

  Specifically, using a single-screw extruder with a vent having a diameter of 65 mm, a L / D = 32, barrier flight type screw with a polymer filter (filtration accuracy of 5 μm) and a T-die at the tip, treatment at 25 kg / hour Melt film formation was performed at a speed. Using the first roll (R1) (elastic touch roll), the second roll (R2) (cast roll), and the third roll (R3), which are chill-plated cooling rolls, the temperature of each cooling roll is set to R1. / R2 / R3 = 95/100/85 ° C., and the angle θ formed by the molten resin film of the (meth) acrylic resin composition extruded from the T-die outlet and the vertical plane including the gap between R1 and R2 is 5 °. Set to. And after casting the molten resin film on R1 and obtaining an unstretched film having a thickness of 128 μm, it is continuously supplied to an oven longitudinal stretching machine as it is, the oven temperature is set to 136 ° C., and a stretching ratio of 1. The film was stretched 6 times. Next, the stretched film was wound up with a winder to obtain a vertically stretched film roll having an average thickness of 80 μm.

  Next, the obtained longitudinally stretched film roll is unwound from a unwinding machine, is gripped at a position 20 mm from both ends with a 2 inch clip, and is supplied to a tenter stretching machine. The oven temperature is set to 138 ° C., and the draw ratio is 2 in the transverse direction. The transverse stretching was performed by a factor of 0.0. Next, the stretched film was wound up with a winder to obtain a roll film having an average thickness of 40 μm. The obtained film was cut into a size of 50 mm × 100 mm to produce a single-wafer (multiple) film (B-1).

[Example 2]
The same operation as in Example 1 was performed except that the input rate of the ultraviolet absorber was changed to 0.79 parts / hour. The obtained (meth) acrylic resin composition was (A-2), the film obtained in the same manner as in Example 1 was (B-2), and the same measurements and evaluations as in Example 1 were performed. .

Example 3
The same operation as in Example 1 was performed except that the input rate of the ultraviolet absorber was 1.08 parts / hour. The obtained (meth) acrylic resin composition was (A-3), the film obtained by the same method as in Example 1 was (B-3), and the same measurements and evaluations as in Example 1 were performed. .

[Comparative Example 1]
The same operation as in Example 1 was performed except that the input rate of the ultraviolet absorber was changed to 1.45 parts / hour. The obtained (meth) acrylic resin composition was set to (A-4), the film obtained by the same method as Example 1 was set to (B-4), and the same measurement and evaluation as Example 1 were performed. .

[Comparative Example 2]
A film was produced from the (meth) acrylic resin composition (A-2) obtained in Example 2 by performing open film formation.

  Specifically, using a single-screw extruder with a vent having a diameter of 65 mm, a L / D = 32, barrier flight type screw with a polymer filter (filtration accuracy of 5 μm) and a T-die at the tip, treatment at 25 kg / hour Melt film formation was performed at a speed. Using the second roll (R2) (cast roll) and the third roll (R3), which are chill-plated cooling rolls, the temperature of each cooling roll is R2 / R3 = 120 ° C./95° C. Extruded from the exit. The extruded (meth) acrylic resin composition molten resin film was cast on R2 to obtain an unstretched film having a thickness of 128 μm.

  Thereafter, the film was continuously supplied to an open longitudinal stretching machine as it was, and the stretching was performed at a stretching ratio of 1.6 times in the longitudinal direction at an open temperature of 136 ° C. Next, the stretched film was wound up with a winder to obtain a vertically stretched film roll having an average thickness of 80 μm.

  Next, the obtained longitudinally stretched film roll is unwound from a unwinding machine, is gripped at a position 20 mm from both ends with a 2 inch clip, and is supplied to a tenter stretching machine. The oven temperature is set to 138 ° C., and the draw ratio is 2 in the transverse direction. The transverse stretching was performed by a factor of 0.0. Next, the stretched film was wound up with a winder to obtain a roll film having an average thickness of 40 μm. The obtained film was cut into a size of 50 mm × 100 mm to produce a single-wafer (multiple) film (B-5). The same measurement and evaluation as in Example 1 were performed on the film (B-5).

  The present invention can be used for an optical film.

Claims (8)

A (meth) acrylic film comprising a thermoplastic resin composition containing a (meth) acrylic resin and an ultraviolet absorber having a molecular weight of less than 700;
A (meth) acrylic film having a contact angle with pure water of 76 ° or less.   The (meth) acrylic film according to claim 1, wherein the ultraviolet absorber is a benzotriazole-based ultraviolet absorber. The (meth) acrylic film according to claim 2, wherein the benzotriazole-based ultraviolet absorber is an ultraviolet absorber represented by the following general formula (1):

_(Wherein, R 1, _{R 2} are each independently a hydrogen atom or,, .R ₃ represents an alkyl group having 1 to 20 carbon atoms (the alkyl group may have a substituent) And R ₄ each independently represents a hydrogen atom or a halogen atom, L represents an alkylene group having 1 to 4 carbon atoms).   The (meth) acrylic system according to any one of claims 1 to 3, wherein the transmittance at 400 nm is 85% or more and the transmittance at 380 nm is 35% or less when the transmittance at 500 nm is 100%. the film.   The optical film using the (meth) acrylic-type film of any one of Claims 1-4.   A polarizer protective film using the optical film according to claim 5.   A polarizing plate comprising the polarizer protective film according to claim 6.   An image display device comprising the polarizing plate according to claim 7.

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