JP2007119565A - Resin film, its manufacturing method and display member using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin film having transparency, high heat resistance, and a small phase difference in the plane and in the thickness direction, and a method for manufacturing the above resin film. <P>SOLUTION: The resin film contains a ring structure, has a glass transition temperature of not lower than 110°C, and meets -0.001<R (550)/d<0.001 and -0.007<Rth (590)/d<0.007. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a highly heat-resistant and optically isotropic resin film, a production method, and uses thereof.

  More specifically, the resin film of the present invention relates to a resin film excellent in transparency, optical isotropy, and heat resistance used for a display material such as a liquid crystal display, for example, as a polarizer protective film.

  Conventionally, a polarizing plate having a three-layer structure in which polyvinyl alcohol (PVA) doped with iodine is used as a polarizer and a polarizer protective film is laminated on both sides thereof is generally used.

The properties required for a polarizer protective film are moderate moisture absorption, high light transmittance, low haze, heat resistance, etc., and satisfying these, inexpensive triacetyl cellulose (TAC) is widely used as a polarizer protective film. Has been used. (Patent Document 1)
However, as the use of polarizing plates has expanded from small displays to large liquid crystal televisions, it has become clear that retardation in the TAC film plane and retardation in the film thickness direction have an adverse effect on the viewing angle of display devices. .

  On the other hand, cyclic polyolefin is known as an optically isotropic film (Patent Document 2).

  Cyclic polyolefin has a very low moisture absorption of 0.1% or less, which is a great merit for many applications. However, in the polarizer protective film, since PVA holds water, an appropriate moisture absorption rate is required, and the low moisture absorption rate of the cyclic polyolefin becomes a drawback.

  Another optical isotropic film is polymethyl methacrylate (PMMA). However, PMMA suffers from deformation due to its low heat resistance, and also has a problem of being easily broken during processing due to its low toughness.

  For the purpose of improving heat resistance, films having glutaric anhydride units or lactone ring units are disclosed (Patent Documents 3 and 4).

  However, if the heat resistance is simply improved by adjusting the composition of the resin film, the flexibility is insufficient and the resin film is easily cracked by bending stress, and sufficient toughness required during processing cannot be obtained.

  For the purpose of simultaneously improving the heat resistance and toughness of a resin film, a film is disclosed in which a crosslinked elastic body is contained in a resin into which a glutaric anhydride unit is introduced (Patent Document 5).

  However, in Patent Document 5, since styrene is copolymerized, retardation in the film plane and in the thickness direction is developed, and development to a polarizer protective film or the like that requires optical isotropy is difficult. there were.

Furthermore, although there is a disclosure of improving the toughness by stretching a film obtained by melt film formation, a phase difference of 5 to 10 nm appears in the in-plane direction. Conventionally, a phase difference of 10 nm or less has not been a problem. However, as liquid crystal displays have become more detailed, even a phase difference of 10 nm or less has become a problem. Furthermore, when the film obtained by melt film formation is stretched, there is a problem that a retardation in the thickness direction is developed (Patent Document 6).
Japanese Patent Publication No.59-51911 Japanese Patent Publication No. 2-9619 JP 2004-2711 A Japanese Patent Laid-Open No. 2002-60424 JP 2000-178399 A JP 2005-162835 A

The present invention has been achieved as a result of studying the solution of the problems in the prior art described above as an issue. That is, an object of the present invention is to provide a resin film having an appropriate moisture absorption rate, transparent, high heat resistance, and small in-plane and thickness direction retardation. Furthermore, the other object of this invention is to provide the manufacturing method of the said resin film.

The present invention for achieving the above object has the following configurations [1] to [10].
That is,
[1] A resin film containing a ring structure represented by the following structural formula (1) and satisfying the following (i) to (v).

(I) When the film thickness is d (μm) and the phase difference in the film plane with respect to light having a wavelength of 550 nm is R (550) (nm), the following formula (a) is satisfied: −0.001 <R ( 550) / d <0.001 (A)
(Ii) When the film thickness is d (μm) and the retardation in the film surface with respect to light having a wavelength of 590 nm is Rth (590) (nm), the following equation (ii) is satisfied: −0.007 <Rth ( 590) / d <0.007 (i)
(Iii) Film thickness d (μm) is 1 to 100 μm
(Iv) Glass transition temperature is 110 ° C. or higher (v) Film thickness unevenness is 5% or less

R ¹ : Hydrogen or a hydrocarbon group having 1 to 10 carbon atoms R ² : Hydrogen or a hydrocarbon group having 1 to 10 carbon atoms R ³ : Hydrogen or a hydrocarbon group having 1 to 10 carbon atoms [2] The following formula (U) And the resin film as described in [1] which satisfies (e).

R (450) / R (650) ≧ 1.00 (U)
R (650) / R (753) ≦ 1.00 (E)
[3] The resin film according to [1] or [2], wherein a photoelastic coefficient with respect to light having a wavelength of 550 nm is −2 × 10 ⁻¹² / Pa or more and 2 × 10 ⁻¹² / Pa or less.

  [4] The resin film according to any one of [1] to [3], which has an elongation at break of 5% or more.

  [5] The material according to any one of [1] to [4], wherein a main material is a mixture of 100 parts by mass of the resin (A) containing a ring structure and 0.1 to 50 parts by mass of the elastic particles (B). Resin film.

  [6] A production method comprising producing the resin film according to any one of [1] to [5] using a solution casting method.

  [7] A member for display material having the resin film according to any one of [1] to [5].

  [8] A polarizing plate protective film having the resin film according to any one of [1] to [5].

  [9] A film with retardation having R (550) / d of 0.001 or more using the resin film according to any one of [1] to [5] as an intermediate.

  [10] A prism sheet, lens and / or screen in which at least one surface of the resin film according to any one of [1] to [5] has an arbitrary shape.

  According to the present invention, a resin film having an appropriate moisture absorption rate, transparent, high heat resistance and small in-plane and thickness direction retardation is obtained.

  Hereinafter, preferred embodiments of the present invention will be described.

  The resin film of the present invention needs to have a ring structure represented by the following structural formula (1).

  In conventional acrylic films, it has been difficult to achieve both a glass transition temperature (Tg) exceeding 100 ° C. and elongation exceeding 5% and optical isotropy.

  On the other hand, in the present invention, by containing the lactone ring structure represented by the structural formula (1), Tg can be made 110 ° C. or higher without impairing other properties. Regarding the Tg, the Tg of the resin film is determined by the degree of freedom of the resin structure, and those having a small degree of freedom, for example, aromatic polyimide, have a Tg exceeding 400 ° C. On the other hand, Tg of polymethyl methacrylate (PMMA), which is a flexible aliphatic polymer having a high degree of freedom, is less than 100 ° C. The resin film of this invention can improve heat resistance by containing the ring structure represented by Structural formula (1). In addition, a small phase difference is required for optical isotropic applications. Here, when an aromatic ring having many π electrons is introduced, the heat resistance is improved more than the introduction of an alicyclic structure, but at the same time, there is a problem that birefringence increases and a phase difference is easily developed. For this reason, it is most preferable to contain a lactone ring structure in order to improve heat resistance while maintaining the optical isotropy.

  Furthermore, the resin film of the present invention is required to satisfy the following (i) to (v).

(I) When the thickness is d (μm) and the retardation in the film surface for light having a wavelength of 550 nm is R (550) (nm), the following formula (a) is satisfied: −0.001 <R (550 ) / D <0.001 (A)
When the absolute value of R (550) / d is 0.001 or more, problems such as deterioration of the viewing angle may occur when it is used as a polarizer protective film. The absolute value of R (550) / d is more preferably 0.0005 or less, and still more preferably 0.0003 or less.
In an optical isotropic film such as a polarizer protective film, R (550) / d is preferably as small as possible, and 0 is ideal. The polarizer protective film preferably transmits the incident light without giving any phase difference, and this characteristic is obtained when the absolute value of R (550) / d is in the above-described range. In addition, the phase difference with respect to the light beam with a wavelength of 550 nm of the present invention is determined by using an automatic birefringence meter (KOBRA-21ADH) manufactured by Oji Scientific Co., Ltd. The phase difference with respect to the light beam with a wavelength of 548.3 nm, the phase difference with respect to the light beam with a wavelength of 628.2 nm, the phase difference with respect to the light beam with a wavelength of 752.7 nm are measured, and the wavelength of Cauchy is calculated from the phase difference (R) and the measurement wavelength (λ) at each wavelength. The coefficients a to d of the dispersion formula (R (λ) = a + b / λ2 + c / λ4 + d / λ6) are obtained, and the value obtained by substituting the wavelength 550 nm (λ = 550) into the Cauchy wavelength dispersion formula. R (λ) at a wavelength λnm other than the wavelength of 550 nm is a value obtained in the same manner. In order to obtain such an optically isotropic resin film, it is effective not to introduce an additive or a copolymer component that develops a phase difference, or to reduce the draw ratio during film formation. is there.

  (Ii) In the present invention, when the thickness is d (μm), the refractive index in the orthogonal axis direction in the resin film plane with respect to the light beam with a wavelength of 590 nm is nx and ny (however, nx ≧ ny), and the resin film with respect to the light beam with a wavelength of 590 nm When the refractive index in the thickness direction is nz and the thickness of the resin film is d (nm), the thickness direction retardation Rth (590) (nm) defined by the following formula satisfies the following formula (ii). is required. In an optical isotropic film such as a polarizer protective film, Rth (590) / d is preferably as small as possible, and 0 is ideal. In practice, the problem is the absolute value of Rth (590), but this value is proportional to the thickness. Therefore, in the present invention, it is defined by birefringence represented by Rth (590) / d.

Thickness direction retardation Rth (nm) = d × {(nx + ny) / 2−nz}
−0.007 <Rth (590) / d <0.007 (i)
When the absolute value of Rth (590) / d is 0.007 or more, problems such as deterioration of the viewing angle may occur when it is used as a polarizer protective film. The absolute value of Rth (590) / d is more preferably 0.003 or less, still more preferably 0.001 or less. The polarizer protective film preferably transmits the incident light without giving any phase difference, and this characteristic is obtained when the absolute value of Rth (590) / d is in the above-described range.

In applications that require optical isotropy in the thickness direction, the thickness direction retardation Rth / d is preferably smaller. In order to obtain such a resin film having a small thickness direction retardation Rth / d, it is necessary not to introduce an additive or a copolymer component that develops a thickness direction retardation, or in the film plane or in the thickness direction. It is effective to lower the draw ratio during film formation.
(Iii) In the present invention, the thickness needs to be 1 to 500 μm. When used as an optical film, if the thickness is less than 1 μm, elongation or distortion may occur with respect to external stress. On the other hand, if it exceeds 500 μm, the light transmittance may be lowered or haze may be increased. Needless to say, the thickness is determined by the application, but is preferably 10 to 200 μm, more preferably 20 to 80 μm.

  (Iv) In the present invention, the glass transition temperature needs to be 110 ° C. or higher. More preferably, it is 120 degreeC or more, More preferably, it is 125 degreeC or more. When the temperature is less than 110 ° C., a dimensional change may occur in the process of manufacturing the polarizing plate and the use environment.

  (V) In the present invention, the thickness unevenness of the film needs to be 5% or less. Conventionally, the polymer itself containing the ring structure represented by Structural Formula (1) has been known. However, there is a problem that a phase difference of 5 to 10 nm is caused because the film is formed by the melt film forming method. Further, in melt film formation, there is a problem that the base stripes are easily attached to the film and the film thickness unevenness is large. When stretching is performed for the purpose of improving this, there is a problem that the in-plane phase difference is further increased, and at the same time, there is a problem that a difference (Rth) between the in-plane and thickness directions is increased. That is, in the prior art, a film containing the structure represented by the structural formula (1) and satisfying (i) to (v) has not been known. In particular, in order to satisfy (v), either a method for obtaining an unstretched film with small thickness unevenness using a solution casting method, or a method for reducing the expression of retardation by adding elastic particles is used. It is essential.

  For example, in the present invention, by forming a polymer having the structural formula (2) unit: methyl methacrylate = 20: 80 parts by mass by a solution casting method, the thickness is 102 μm, the thickness unevenness is 4%, the retardation is 0.3 nm, An Rth-0.8 nm film can be obtained. At this time, R (550) / d is 0.000029 and Rth (590) / d is -0.000078.

    Further, in the resin film of the present invention, the retardation R (450), R (650), and R (753) in the film surface with respect to light having wavelengths of 450, 650, and 753 nm satisfy the following formulas (U) and (E). Is a preferred embodiment.

R (450) / R (650) ≧ 1.00 (U)
R (650) / R (753) ≦ 1.00 (E)
Films with chromatic dispersion satisfying the formula (U) are known, but chromatic dispersion curves are monotonically increasing or monotonically decreasing, and films that satisfy the equations (U) and (E) at the same time are known. Absent. The phase difference increases from blue (wavelength 450 nm) to red (wavelength 650 nm), and the phase difference decreases in the region of wavelength 650 nm or more, thereby reducing redness deviation. In addition, it defined at 753 nm as a representative value of the long wavelength. In the phase difference measuring device, the actually measured wavelength differs depending on the device. Since the apparatus we used measures a phase difference of 753 nm, this value is used as an index. In the case of an apparatus that does not actually measure 753 nm, the value of R (753) is obtained by the equation shown in the example.

The retardation of a general polymer film is “forward dispersion” that decreases or “reverse dispersion” that increases with respect to the wavelength, and there is a limit to optical compensation. In the resin film of the present invention, the phase difference decreases in the low wavelength region and the specific dispersion increases in the long wavelength region, so that the degree of freedom of optical compensation increases. In the present invention, an unstretched film obtained by forming a polymer having the structural formula (2) unit: methyl methacrylate = 20: 80 parts by mass using a solution casting method is stretched 200% at 120 ° C. and has a thickness of 63 μm. The film has R (450) = 98.0
R (650) = 95.3
R (753) = 95.7
And
R (450) / R (650) = 1.028
R (650) / R (753) = 0.996
This gives a unique chromatic dispersion. By using this retardation film, the blue and red shifts of the liquid crystal display, which has been a problem in the past, can be greatly reduced.

In the present invention, it is also preferred that the photoelastic coefficient for light having a wavelength of 550 nm is −2 × 10 ⁻¹² / Pa or more and 2 × 10 ⁻¹² / Pa or less.

A polarizing plate receives stress in the manufacturing process and use environment. Here, when the absolute value of the photoelastic coefficient is 2 × 10 ⁻¹² / Pa or more, a phase difference may occur due to stress. Preferably it is 1.5 * 10 < ^-12 > / Pa or less, More preferably, it is 1 * 10 < ^-12 > / Pa or less.
By photoelastic coefficient of ^{-2 × 10 -12 / Pa~2 × 10} -12 / Pa, when used in a liquid crystal television having a large screen, the thermal expansion of the other members bonded to the resin film, or residual It is preferable because the change in retardation is small even when the resin film is stressed due to stress or the like. More photoelastic coefficient is small, preferably for the phase difference change is small with respect to stress, and more preferably from ^{-1 × 10 -12 / Pa~1 × 10} -12 / Pa. Although the photoelastic coefficient of a resin film is generally small, if styrene or maleimide is copolymerized or an aromatic substituent is introduced to improve heat resistance, the photoelastic coefficient is also increased. The resin film of the present invention can achieve both improved heat resistance and a low photoelastic coefficient due to the 6-membered ring structure. For example, in the present invention, a photoelastic coefficient of 1.3 × 10 ⁻¹² / Pa is obtained by forming a polymer having the structural formula (2) unit: methyl methacrylate = 20: 80 parts by mass by a solution casting method. .

It is also preferable that the elongation at break is 5% or more. The film of the present invention can achieve 5% or more by adding elastic particles. In the present invention, the elongation at break in at least one direction is more preferably 10% or more, and more preferably 15% or more. Further, the elongation at break in the orthogonal direction is more preferably 10% or more. It is preferable that the elongation at break of the resin film is 10% or more because the resin film has appropriate flexibility, film breakage during film formation and processing is reduced, and workability such as slit property is improved. The elongation at break of such a resin film is measured by a method based on JIS-C2318. The upper limit of the elongation at break of the resin film is not particularly limited, but it is considered that it is practically about 50%. In order to obtain a resin film having such elongation at break, the molecular weight of the resin, the content of cyclic units, the composition of the elastic particles, the particle diameter, the added amount, the dispersion state in the resin film, etc. may be adjusted as appropriate. .
For example, in the present invention, a product obtained by kneading AC203420 parts by mass of Gantz Kasei Co., Ltd. with 80 parts by mass of a polymer having the structural formula (2) unit: methyl methacrylate = 20: 80 parts by mass is produced by a solution casting method. By forming a film, the elongation at break is 10%.

  The structure other than the lactone ring structure of the resin film of the present invention will be described. As a structure other than the ring structure, an acrylic resin and a methacrylic acid resin are preferable in order to satisfy the characteristics of moisture absorption, total light transmittance, haze, and retardation. As the acrylic resin and methacrylic acid resin, methyl methacrylate is preferable because it satisfies the above characteristics. Preferred specific examples of unsaturated carboxylic acid alkyl ester monomers other than methyl methacrylate include ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, and (meth) acrylic. T-butyl acid, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, chloromethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, (meth ) 3-hydroxypropyl acrylate, 2,3,4,5,6-pentahydroxyhexyl (meth) acrylate and 2,3,4,5-tetrahydroxypentyl (meth) acrylate.

  Furthermore, the resin film of the present invention may have a ring structure other than the lactone ring. Other alicyclic structures include a glutaric anhydride structure, a norbornene structure, a cyclopentane structure, and the like. As for optical isotropy and heat resistance, the same effect can be obtained by using any structure. However, for the introduction of norbornene structure, cyclopentane structure, etc., expensive materials having these structures are used, or these structures are used. It is industrially disadvantageous because an expensive raw material to be a precursor is used and a target structure needs to be obtained through several steps of reaction. On the other hand, a glutaric anhydride structure is very industrially advantageous because it is obtained from an acrylic raw material by a one-step dehydration and / or dealcoholization reaction.

  As for the polymerization method of the resin, a known polymerization method such as bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization or the like, which is basically radical polymerization, can be used. Polymerization and suspension polymerization are particularly preferred.

  Hereinafter, the terms resin (A) and elastic particles (B) are used to describe the composition ratio in detail. Resin (A) indicates a resin containing a ring structure represented by the formula (1) and other copolymer components. The elastic particles (B) indicate elastic particles added to the resin (A). As for the elastic particles (B), the multilayered polymer is further referred to as (B-1), and the graft copolymer is referred to as (B-2).

  The content of the ring structural unit represented by the general formula (1) in the resin (A) of the present invention is preferably 10 to 50 parts by mass, more preferably 100 parts by mass of the resin (A) containing the ring structure. Is 15 to 45 parts by mass, most preferably 20 to 25 parts by mass. When the ring structural unit is less than 10 parts by mass, the effect of improving heat resistance may be reduced. Further, when the ring structural unit exceeds 50 parts by mass, the elongation at break may be deteriorated. The improvement in heat resistance and the improvement in toughness are in a trade-off relationship and can be adjusted by the content of the ring structural unit. For this reason, the content of the ring structural unit should adopt an arbitrary value in 10 to 50 parts by mass depending on the use. For example, although Tg of 120 ° C. or higher is required for the polarizing plate protective film, the content of the ring structural unit is most preferably 20 to 25 parts by mass in consideration of Tg reduction due to addition of elastic particles. If the content of the ring structural unit is 20 to 25 parts by mass, it has a Tg of 120 to 130 ° C. after addition of the elastic particles and has sufficient toughness.

  In the present invention, by dispersing the elastic particles (B) in the above resin (A), excellent impact resistance can be imparted without greatly impairing the excellent properties of the resin (A). The elastic particles (B) are composed of a layer containing one or more rubber-like polymers and one or more layers made of different polymers, and these layers are adjacent to each other. A so-called core-shell type polymer (B-1) or a graft copolymer (B-1) obtained by copolymerizing a monomer mixture comprising a vinyl monomer in the presence of a rubbery polymer. -2) etc. can be preferably used.

  As the core-shell type multilayer structure polymer (B-1) used in the present invention, the number of layers constituting the core-shell type polymer (B-1) is not particularly limited, and may be two or more layers. Although it may be four or more layers, it needs to be a multilayer structure polymer having at least one rubber layer inside.

  In the multilayer structure polymer (B-1) of the present invention, the type of the rubber layer is not particularly limited as long as it is composed of a polymer component having rubber elasticity. For example, a rubber composed of a polymer obtained by polymerizing an acrylic component, a silicone component, a styrene component, a nitrile component, a conjugated diene component, a urethane component or an ethylene component, a propylene component, an isobutene component, and the like can be given. Preferred rubbers include, for example, acrylic components such as ethyl acrylate units and butyl acrylate units, silicone components such as dimethylsiloxane units and phenylmethylsiloxane units, styrene components such as styrene units and α-methylstyrene units, acrylonitrile units, A rubber composed of a nitrile component such as a methacrylonitrile unit and a conjugated diene component such as a butanediene unit or an isoprene unit. A rubber composed of a combination of two or more of these components is also preferable. For example, (1) acrylic components such as ethyl acrylate units and butyl acrylate units and silicones such as dimethylsiloxane units and phenylmethylsiloxane units. Rubber composed of components, (2) rubber composed of acrylic components such as ethyl acrylate units and butyl acrylate units, and styrene components such as styrene units and α-methylstyrene units, (3) ethyl acrylate units and Rubber composed of acrylic components such as butyl acrylate units and conjugated diene components such as butanediene units and isoprene units, and (4) acrylic components such as ethyl acrylate units and butyl acrylate units, dimethylsiloxane units and phenylmethylsiloxanes Unit etc. Rubber composed of styrene component such as silicone component and styrene units and α- methyl styrene units and the like. In addition to these components, a rubber obtained by crosslinking a copolymer composed of a crosslinking component such as a divinylbenzene unit, an allyl acrylate unit, and a butylene glycol diacrylate unit is also preferable.

  In the multilayer structure polymer (B-1) of the present invention, the type of layer other than the rubber layer is not particularly limited as long as it is composed of a polymer component having thermoplasticity, but from the rubber layer. Is preferably a polymer component having a high glass transition temperature. Polymers having thermoplastic properties include unsaturated carboxylic acid alkyl ester units, unsaturated carboxylic acid units, unsaturated glycidyl group-containing units, unsaturated dicarboxylic acid anhydride units, aliphatic vinyl units, and aromatic vinyls. Examples include polymers containing at least one unit selected from system units, vinyl cyanide units, maleimide units, unsaturated dicarboxylic acid units and other vinyl units. Among them, unsaturated carboxylic acids A polymer containing at least one unit selected from an alkyl ester unit, an unsaturated glycidyl group-containing unit, and an unsaturated dicarboxylic acid anhydride unit is preferable, and further, an unsaturated glycidyl group-containing unit and an unsaturated dicarboxylic acid A polymer containing at least one unit selected from anhydride-based units is more preferable.

  Although it does not specifically limit as a monomer used as the raw material of the said unsaturated carboxylic-acid alkylester type | system | group unit, (meth) acrylic-acid alkylester is used preferably. Specifically, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, t-butyl (meth) acrylate, (meth) acrylic N-hexyl acid, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, stearyl (meth) acrylate, octadecyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, ( Chloromethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2,3,4,5,6 (meth) acrylic acid -Pentahydroxyhexyl, 2,3,4,5-tetrahydroxypentyl (meth) acrylate, amino acid acrylate Examples include ethyl, propylaminoethyl acrylate, dimethylaminoethyl methacrylate, ethylaminopropyl methacrylate, phenylaminoethyl methacrylate, and cyclohexylaminoethyl methacrylate, and from the viewpoint that the effect of improving impact resistance is large ( Methyl methacrylate is preferably used. These units can be used alone or in combination of two or more.

  The unsaturated carboxylic acid monomer is not particularly limited, and examples thereof include acrylic acid, methacrylic acid, maleic acid, and further a hydrolyzate of maleic anhydride. Acrylic acid is particularly excellent in terms of thermal stability. Methacrylic acid is preferable, and methacrylic acid is more preferable. These can be used alone or in combination.

  The monomer used as the raw material for the unsaturated glycidyl group-containing unit is not particularly limited, and is glycidyl (meth) acrylate, glycidyl itaconate, diglycidyl itaconate, allyl glycidyl ether, styrene-4-glycidyl ether. And 4-glycidylstyrene, and glycidyl (meth) acrylate is preferably used from the viewpoint that the effect of improving impact resistance is great. These units can be used alone or in combination of two or more.

  Examples of the monomer used as a raw material for the unsaturated dicarboxylic acid anhydride unit include maleic anhydride, itaconic anhydride, glutaconic anhydride, citraconic anhydride, and aconitic anhydride, and the effect of improving impact resistance. From the standpoint of large, maleic anhydride is preferably used. These units can be used alone or in combination of two or more.

  Examples of the monomer that is a raw material for the aliphatic vinyl-based unit include ethylene, propylene, and butadiene. Examples of the monomer that is a raw material for the aromatic vinyl-based unit are styrene, α-methylstyrene, 1 -Vinyl naphthalene, 4-methyl styrene, 4-propyl styrene, 4-cyclohexyl styrene, 4-dodecyl styrene, 2-ethyl-4-benzyl styrene, 4- (phenylbutyl) styrene, halogenated styrene, etc. Acrylonitrile, methacrylonitrile, ethacrylonitrile, etc. are used as the raw material for the vinyl-based unit, and maleimide, N-methylmaleimide, N-ethylmaleimide are used as the monomer for the maleimide-based unit. N-propylmaleimide, N-isopropylmaleimide, Examples of monomers that can be used as raw materials for the unsaturated dicarboxylic acid units include maleic acid and maleic acid such as -cyclohexylmaleimide, N-phenylmaleimide, N- (p-bromophenyl) maleimide, and N- (chlorophenyl) maleimide. Monoethyl ester, itaconic acid, phthalic acid, and the like, which are monomers used as raw materials for the other vinyl units, include acrylamide, methacrylamide, N-methylacrylamide, butoxymethylacrylamide, N-propylmethacrylamide, N- Vinyldiethylamine, N-acetylvinylamine, allylamine, methallylamine, N-methylallylamine, p-aminostyrene, 2-isopropenyl-oxazoline, 2-vinyl-oxazoline, 2-acryloyl-oxazoline, and 2-styrene Examples include ril-oxazoline, and these monomers can be used alone or in combination of two or more.

  In the multilayer structure polymer (B-1) containing the rubbery polymer of the present invention, the kind of the outermost layer is not particularly limited, and is an unsaturated carboxylic acid alkyl ester unit or an unsaturated carboxylic acid unit. Unsaturated glycidyl group-containing units, aliphatic vinyl units, aromatic vinyl units, vinyl cyanide units, maleimide units, unsaturated dicarboxylic acid units, unsaturated dicarboxylic anhydride units, and other vinyl types And at least one selected from polymers containing units and the like. Among them, unsaturated carboxylic acid alkyl ester units, unsaturated carboxylic acid units, unsaturated glycidyl group-containing units, and unsaturated dicarboxylic anhydrides At least one selected from polymers containing system units is preferred, and further unsaturated carboxylic acid alkyl ester system units, unsaturated Polymers containing carboxylic acid units is more preferable.

  Furthermore, in the present invention, when the outermost layer in the multilayer polymer (B-1) is a polymer containing an unsaturated carboxylic acid alkyl ester unit and an unsaturated carboxylic acid unit, by heating, In the same manner as in the production of the thermoplastic copolymer (A) of the present invention described above, the intramolecular cyclization reaction proceeds, and the glutaric anhydride unit represented by the general formula (1) is generated. It was. Therefore, a multilayer structure polymer (B-1) having a polymer containing an unsaturated carboxylic acid alkyl ester unit and an unsaturated carboxylic acid unit in the outermost layer is blended with the thermoplastic copolymer (A), In the thermoplastic copolymer (A) which becomes a continuous phase (matrix phase) by heating and kneading under such conditions, the glutaric acid represented by the above general formula (1) is substantially formed in the outermost layer. By dispersing the multilayer structure polymer (B-1) having a polymer containing an anhydride unit, a good dispersion state is possible without agglomeration, and with improved mechanical properties such as impact resistance, It is considered that extremely high transparency can be expressed.

  The monomer used as the raw material for the unsaturated carboxylic acid alkyl ester unit herein is not particularly limited, but (meth) acrylic acid alkyl ester is preferred, and methyl (meth) acrylate is more preferred. Preferably used.

  Further, the monomer used as a raw material for the unsaturated carboxylic acid unit is not particularly limited, but (meth) acrylic acid is preferable, and methacrylic acid is more preferably used.

  As a preferable example of the multilayer structure polymer (B-1) of the present invention, the core layer is butyl acrylate / styrene polymer, the outermost layer is methyl methacrylate / glutaric acid anhydride represented by the above general formula (1). A copolymer consisting of a physical unit, or a methyl methacrylate / glutaric anhydride unit represented by the above general formula (1) / methacrylic acid polymer, and the core layer is a dimethylsiloxane / butyl acrylate polymer. The outer layer is a methyl methacrylate polymer, the core layer is a butanediene / styrene polymer and the outermost layer is a methyl methacrylate polymer, and the core layer is a butyl acrylate polymer and the outermost layer is a methyl methacrylate polymer ("/" Indicates copolymerization). Furthermore, a preferable example is one in which either one or both of the rubber layer and the outermost layer is a polymer containing a glycidyl methacrylate unit. Among them, the core layer is butyl acrylate / styrene polymer, and the outermost layer is methyl methacrylate / a copolymer of glutaric anhydride units represented by the above general formula (1), or methyl methacrylate / the above general formula. The glutaric anhydride unit / methacrylic acid polymer represented by (1) approximates the refractive index with the resin (A) which is a continuous phase (matrix phase), and in the resin composition It becomes possible to obtain a good dispersion state, and since transparency that can satisfy the demand for more advanced in recent years appears, it can be preferably used.

  As a weight average particle diameter of the multilayer structure polymer (B-1) of this invention, it is preferable to set it as 50-400 nm, More preferably, it is 100-200 nm. When the weight average particle size is less than 50 nm, the toughness may not be sufficiently improved, and when it exceeds 400 nm, the Tg may decrease.

  In the multilayer structure polymer (B-1) of the present invention, the weight ratio of the core and the shell is not particularly limited, but the core layer is 50 parts by mass or more with respect to 100 parts by mass of the entire multilayer structure polymer. 90 parts by mass or less, and more preferably 60 parts by mass or more and 80 parts by mass or less.

  As the multilayer structure polymer of the present invention, a commercially available product that satisfies the above-described conditions may be used, or it may be prepared by a known method.

  Commercially available products of multilayer structure polymers include, for example, “Metablene” manufactured by Mitsubishi Rayon Co., Ltd. “Kane Ace” manufactured by Kaneka Chemical Industry Co., Ltd., “Paraloid” manufactured by Kureha Chemical Industry Co., Ltd. “Staffyroid” manufactured by Kogyo Co., Ltd., “Parapet SA” manufactured by Kuraray Co., Ltd. and the like can be mentioned, and these can be used alone or in combination of two or more.

  The weight average particle diameter of the elastic particles (B) is the sodium alginate method described in “Rubber Age, Vol. 88, p. 484-490 (1960), by E. Schmidt, P. H. Biddison”. Using the fact that the diameter of the polybutadiene particles to be creamed differs depending on the concentration of sodium alginate, measure the particle size of 50% cumulative weight fraction from the creamed weight fraction and the cumulative weight fraction of sodium alginate concentration. Can do.

  Here, as a method of blending the elastic particles and other additives into the resin, for example, after pre-blending the resin or the resin and other additive components, usually at 200 to 350 ° C. by a single or twin screw extruder. A method of uniformly melting and kneading can be used.

  In addition, the substantial composition of the resin (A) and the elastic particles (B) can be analyzed individually by separating the soluble component and the insoluble component with the solvent.

  In this invention, it contains 0.01 mass part or more and 5 mass parts or less of ultraviolet absorbers according to a use with respect to a total of 100 mass parts of resin (A) and an elastic body particle (B), It is characterized by the above-mentioned. Things are also preferable. Any ultraviolet absorber can be used, and examples thereof include benzotriazole, salicylic ester, benzophenone, oxybenzophenone, cyanoacrylate, polymer, and inorganic. Examples of commercially available ultraviolet absorbers include Adeka Stub from Asahi Denka Kogyo Co., Ltd., TINUVIN registered trademark, Uvinul from BASF Corporation, and UV absorber from Johoku Chemical Industry Co., Ltd.

  Aromatic polymers absorb ultraviolet rays due to aromatics in the main chain, so the main chain is cleaved by ultraviolet rays and there is a problem of deterioration, but the resin film of the present invention deteriorates because the main chain portion does not absorb ultraviolet rays. In addition, it is preferable because a desired ultraviolet ray cutting function can be imparted depending on the kind and amount of the ultraviolet absorber to be added. Furthermore, even if the ultraviolet absorber to add is an aromatic compound, since it exists at random, since a phase difference is hard to express, it is preferable.

  The addition amount of the ultraviolet absorber is preferably 0.1 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass in total of the resin (A) and the elastic particles (B). If it is less than 0.1 parts by mass, the desired effect may not be obtained. When the amount exceeds 5 parts by mass, problems such as non-uniform dispersion, a decrease in total light transmittance, and an increase in haze may occur.

  A well-known method can be used for the manufacturing method of the resin film of this invention. That is, manufacturing methods such as a melt film forming method, a solution film forming method, and a hot press method can be used, but a solution film forming method and a melt film forming method can be preferably used. More preferably, when priority is given to the quality of the obtained film, the solution casting method is most preferable. In the case where production speed and cost are prioritized, the melt film forming method is most preferable.

  When forming into a film by the solution casting method, it is preferable that the residual volatile matter in 100 mass parts of resin films containing a residual volatile matter shall be 3 mass parts or less. If the residual volatile content exceeds 3 parts by mass, the apparent Tg will decrease, the winding property of the film will deteriorate due to blocking, the organic solvent will bleed out over time, and the adhesiveness with other members will decrease. This problem is likely to occur.

  In the present invention, the residual volatile content of the resin film is defined as determined by the following evaluation method. Using a thermal mass measuring device, the thermal loss of the resin film is measured in a nitrogen atmosphere under the temperature rising rate of 10 ° C./min, and the residual volatilization is calculated from the mass at 35 ° C. and the mass at 200 ° C. using the following equation Ask for minutes.

  Residual volatile content (parts by mass) of resin film = ((mass at 35 ° C.−mass at 200 ° C.) / Mass at 35 ° C.) × 100.

  The residual volatile content is more preferably 2 parts by mass or less, further preferably 1 part by mass or less, and most preferably 0.5 parts by mass or less. And The lower the residual volatile content in the resin film is, the better, but it is considered to be about 100 ppm in practice.

  Next, the solution film forming method which is a preferable film forming method of the present invention will be described. The solvent for dissolving the resin is not particularly limited, and halogenated hydrocarbon organic solvents such as methylene chloride, ethylene chloride and chloroform, ketone organic solvents such as acetone and methyl ethyl ketone, tetrahydrofuran, dimethylformamide, dimethyl sulfoxide, and N-methyl. Examples include solvents such as -2-pyrrolidone. These solvents may be used alone or in combination of two or more. Among these, a halogen-based solvent is preferred because the drying speed is fast and the residual volatile matter can be reduced. Particularly preferred is methylene chloride.

  When the resin is prepared by solution polymerization, the polymerization solution may be used as it is as an acrylic solution for film formation, or the resin once isolated may be dissolved in the organic solvent to form a resin solution for film formation. .

  As the solvent, in addition to the above solvents, hydrocarbon organic solvents such as cyclohexane, benzene, toluene, xylene, styrene, cyclopentane, and alcoholic organic solvents such as methanol, ethanol, isopropyl alcohol, n-butanol, and tert-butyl alcohol. Solvents, ether organic solvents such as dimethyl ether, diethyl ether, butyl ether, ester organic solvents such as methyl acetate, ethyl acetate, and n-butyl acetate, polyhydric alcohol organic solvents such as ethyl cellosolve, cellosolve acetate, tert-butyl cellosolve, etc. You may use 1 type selected from these, or 2 or more types mixed. By mixing these organic solvents, the viscoelasticity and surface tension of the resin solution may change, and the surface properties and drying characteristics of the resin film, and the peelability from the support may be improved. However, care should be taken because if a large amount of an organic solvent having poor solubility of the resin is mixed, the stability of the resin solution deteriorates and the resin may precipitate.

  Although the density | concentration of a resin solution is suitably adjusted according to the kind of solvent and the target application | coating thickness of resin, the sum total of resin (A) and elastic body particle (B) with respect to 100 mass parts of resin solutions. Is preferably in the range of 5 to 40 parts by mass, and more preferably in the range of 10 to 30 parts by mass. In the present invention, the concentration of the resin solution is the concentration of the resin with respect to the entire resin solution. If the concentration of the resin solution is less than 5 parts by mass, the viscosity is low, and the flatness of the resin film is deteriorated due to the convection of the organic solvent in the initial drying stage of the resin coating, and it takes a long time to dry the organic solvent. This is not preferable because the properties are lowered. On the other hand, if the concentration of the resin solution exceeds 40 parts by mass, the viscosity is high, handling properties are deteriorated, and it is difficult to perform high-precision filtration.

  In order to make the resin solution have good film defects and haze values, it is preferable to remove foreign substances by filtration. Examples of the filter used for such filtration include a filter made of a polymer such as a wire mesh, sintered metal, porous ceramic, glass, polypropylene resin or polyethylene resin, or a filter combining two or more of the above materials.

  The filtration accuracy of this resin solution is preferably 10 μm or less, more preferably 5 μm or less, and even more preferably 1 μm or less. The smaller the filtration accuracy of the resin solution, the better. However, if the filtration accuracy is too small, the frequency of filter replacement due to clogging increases, and the productivity decreases, which is not preferable. The lower limit of the filtration accuracy of the resin solution is considered to be about 0.1 μm.

  The method of applying the resin solution to the support is appropriately selected depending on the viscoelasticity of the resin solution, the coating thickness of the resin film, the type of support, the organic solvent used, and the like, but a forward rotation roll coater, a reverse roll coater, Examples of the coating method include gravure coaters, knife coaters, blade coaters, rod coaters, air doctor coaters, curtain coaters, fountain coaters, kiss coaters, screen coaters, comma coaters, and slit die coaters.

  As the support on which the resin solution is applied, any of a polymer film, a drum, an endless belt, and the like may be used. However, the polymer film is used as the support because the resin film after drying and the support have good peelability. It is preferable. The support of such a polymer film is not particularly limited as long as it is resistant to the organic solvent used in the resin solution. For example, polyethylene terephthalate film, polyethylene naphthalate film, polypropylene film, polyethylene film, polyphenylene sulfide film And aramid film, polyimide film, and the like. Among these, a polyethylene terephthalate film excellent in balance of rigidity, thickness unevenness, defect-free property, cost and the like is preferable. Further, the surface treatment of the polyethylene terephthalate film is not particularly limited, but a surface-coated product is preferable because the peeling force can be easily controlled. Examples of the surface-coated polyester include “Lumirror” manufactured by Toray Industries, Inc., “Therapel” manufactured by Toray Film Processing Co., Ltd., and “Film Binner” manufactured by Fujimori Industry Co.

  The resin solution is applied on a support, dried, and peeled from the support to obtain a resin film. When a polymer film is used as the support, the film thickness is preferably 50 to 200 μm, more preferably 75 to 150 μm. When the film thickness of the support is less than 50 μm, the rigidity of the film is low, and wrinkles are likely to occur at the coating or drying stage, so that problems such as deterioration of the flatness of the resin film are likely to occur. Moreover, when the film thickness of a support body exceeds 200 micrometers, it is not economical and it is unpreferable since problems, such as it being difficult to transmit a heat | fever to a resin film, arise.

  The resin film of the present invention preferably comprises at least three stages of initial drying, intermediate drying, and final drying in the drying process of the resin film coated on the support.

  The drying conditions of the resin film applied to the support should be set appropriately depending on the drying method, the organic solvent used, the viscoelasticity of the resin solution, the glass transition temperature of the resin, etc. If the boiling point of the organic solvent to be used is exceeded, defects of the resin film due to foaming are likely to occur, so that the boiling point is preferably not more than the boiling point of the solvent. If it is too low, it takes a long time to dry the resin film and the productivity is poor, so the lower limit is considered to be about 0 ° C.

  A drying process may further increase the drying process which consists of the above-mentioned three stages of initial drying, intermediate drying, and final drying. In this case, the drying temperature is preferably raised stepwise or continuously from the viewpoint of suppressing foaming. The drying time in each drying stage is preferably about 0.1 to 120 minutes.

  The drying method of the resin film should be selected according to the organic solvent used, the viscoelasticity of the resin solution, the glass transition temperature of the resin, the thickness of the resin film, etc., but hot air jet, drum type, infrared, Examples of the drying method include microwave (induction heating), electromagnetic induction heating, ultraviolet rays, and electron beams.

  The resin film may be dried until final drying on the support, or the support and the resin film may be peeled off during drying and dried again. When drying after peeling, it is preferable to hold or reinforce the film edge for the purpose of preventing deterioration of flatness due to drying shrinkage.

  The resin film of the present invention may be a single layer film or a laminated film. In the case of making a laminated film, for example, a method of once forming one layer and forming another layer thereon, A method of laminating with a composite tube may be used.

In the case of the production method by the melt film forming method, an extruder type melt extrusion apparatus equipped with a single screw or a twin screw extrusion screw can be used. Preferably, a twin screw kneading extruder with L / D = 25 or more and 120 or less is preferable in order to prevent coloring. The melt extrusion temperature for producing the film of the present invention is preferably 150 to 350 ° C, more preferably 200 to 300 ° C. Melt shear rate is preferably 1000 S ^-1 or 5000S ^-1 or less. Moreover, when melt-kneading using a melt-extrusion apparatus, it is preferable to perform the melt-kneading under reduced pressure or the melt-kneading under nitrogen stream from a viewpoint of coloring suppression. Casting method is to measure the melted resin with a gear pump and then discharge it from a T-die die. On the cooled drum, electrostatic application method, air chamber method, air knife method, press roll method, which are known adhesion means per se. It is preferable to obtain an unstretched film by tightly cooling and solidifying it with a cooling medium such as a drum by rapid cooling to room temperature.

  The film thus obtained makes use of its excellent transparency, heat resistance, light resistance, and toughness to make housings for electrical / electronic parts, display material members, automobile parts, mechanical mechanism parts, OA equipment, home appliances, etc. It can be used for various applications such as parts and general miscellaneous goods.

  Here, the display material member is a member for a display device, and particularly indicates a member used for a flat panel display such as a liquid crystal display, a plasma display, a field emission display, and an electroluminescence display. For example, plastic substrate, lens, polarizing plate, polarizing plate protective film, ultraviolet absorbing film, infrared absorbing film, electromagnetic wave shielding film, prism sheet, prism sheet substrate, Fresnel lens, optical disk substrate, optical disk substrate protective film, light guide plate, Examples thereof include a retardation film, a light diffusion film, a viewing angle widening film, a reflection film, an antireflection film, an antiglare film, a brightness enhancement film, a prism sheet, and a conductive film for a touch panel.

  Specific applications of the molded product include, for example, various covers, various terminal boards, printed wiring boards, speakers, microscopes, binoculars, cameras, optical instruments represented by watches, and excellent transparency and heat resistance. From the point of view, finder such as camera, VTR, projection TV, filter, prism, Fresnel lens, etc. as video equipment related parts, various optical disc (VD, CD, DVD, MD, LD, etc.) substrates as optical recording / optical communication related parts Information equipment related parts such as protective films, optical switches, optical connectors, etc., liquid crystal displays, flat panel displays, plasma display light guide plates, Fresnel lenses, polarizing plates, polarizing plate protective films, retardation films, light diffusion films, viewing angles Magnifying film, reflective film, antireflection film, antiglare film Brightness enhancement film, a prism sheet, conductive films for touch panels, covers, etc., are very useful for these various applications, it is particularly useful as a polarizing plate protective film.

  The resin film of the present invention is characterized in that the phase difference is small in the case of unstretched and isotropic biaxial stretching, but this is used as an intermediate product by performing uniaxial stretching or unobtrusive biaxial stretching. It is possible to give a phase difference to obtain a phase difference film. In this case, it is preferable that R (550) / d is 0.001 or more.

  Furthermore, the resin film of the present invention is heated and pressed, or formed into a film using a support provided with an arbitrary shape in solution film formation, and the surface shape of the support is transferred, whereby a prism sheet, a lens or It can be preferably used as a screen.

[Measurement method of physical properties]
Hereinafter, the configuration and effects of the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples. Prior to the description of each example, various physical property measurement methods employed in the example will be described.

(1) Composition of each component The resin film was dissolved in acetone, and this solution was centrifuged at 9000 rpm for 30 minutes to separate into an acetone soluble component and an acetone insoluble component. The acetone-soluble component was dried under reduced pressure at 60 ° C. for 5 hours, and each component unit was quantified to identify each component composition of the resin.

Quantification of each component unit was performed by a proton nuclear magnetic resonance ( ¹ H-NMR) method. ^{In the 1} H-NMR method, for example, in the case of a copolymer consisting of a glutaric anhydride unit, methacrylic acid, and methyl methacrylate, the spectral assignment in a dimethyl sulfoxide heavy solvent is 0.5 to 1.5 ppm peak. Is hydrogen of α-methyl group of methacrylic acid, methyl methacrylate and glutaric anhydride ring compound, peak of 1.6 to 2.1 ppm is hydrogen of methylene group of polymer main chain, peak of 3.5 ppm is methyl methacrylate The carboxylic acid ester (—COOCH ₃ ) of hydrogen, the peak at 12.4 ppm can determine the copolymer composition from the carboxylic acid hydrogen of methacrylic acid and the integral ratio of the spectrum. In addition to the above, in the case of a copolymer containing styrene as another copolymer component, hydrogen of the aromatic ring of styrene is seen at 6.5 to 7.5 ppm, and the copolymer composition is similarly determined from the spectral ratio. Can be determined.

In addition to the ¹ H-NMR method, each component unit can be quantified by infrared spectroscopy. In this method, glutaric anhydride units are characterized by absorption at 1800 cm ⁻¹ and 1760 cm ⁻¹ , and can be distinguished from units derived from vinyl carboxylic acids and units derived from vinyl carboxylic acid alkyl esters.

  The weight average particle diameter of the rubbery polymer is the sodium alginate method described in “Rubber Age, Vol. 88, p. 484-490 (1960), by E. Schmidt, PH B. Biddison”, that is, the concentration of sodium alginate. By using the fact that the diameter of the polybutadiene particles to be creamed differs depending on the particle size, it can be measured by a method of determining the particle size of 50% cumulative weight fraction from the weight proportion of cream and the cumulative weight fraction of sodium alginate concentration.

(2) Haze value and total light transmittance Using a direct reading haze meter manufactured by Toyo Seiki Co., Ltd., a haze value (%) and a total light transmittance (%) at 23 ° C. were measured. The measurement was performed 3 times and the average value was taken.
The total light transmittance and haze are values measured in accordance with JIS-K7361 and JIS-K7136.

(3) Elongation at break The measurement was performed under the following conditions using an automatic tensile strength measuring device “Tensilon AMF / RTA-100” manufactured by Orientec Co., Ltd.
Sample size: width 10mm, length 150mm
Chuck distance 50mm
Tensile speed: 300 mm / min Measurement environment: 23 ° C., 65% RH, tensile Young's modulus was determined from the tangent of the rising portion of the load-elongation curve obtained under atmospheric pressure. Also, the elongation at break was obtained by multiplying the length obtained by subtracting the distance between chucks from the length at the time of film break by the distance between chucks and multiplying by 100. The measurement was performed 5 times and the average value was taken.

(4) Phase difference at wavelength of 550 nm Using an automatic birefringence meter (KOBRA-21ADH) manufactured by Oji Co., Ltd., in the chromatic dispersion measurement mode, the phase difference with respect to the light of wavelength 480.4 nm, the wavelength of 548.3 nm The phase difference with respect to the light beam, the phase difference with respect to the light beam with a wavelength of 628.2 nm, and the phase difference with respect to the light beam with a wavelength of 752.7 nm are measured, and the Cauchy wavelength dispersion formula (R The coefficients a to d of (λ) = a + b / λ2 + c / λ4 + d / λ6) were obtained, and the wavelength 550 nm (λ = 550) was substituted into the Cauchy wavelength dispersion formula. The measurement was performed once.

(5) Thickness direction retardation Rth
Using an automatic birefringence meter (KOBRA-21ADH) manufactured by Oji Scientific Co., Ltd., the refractive index in the direction of the orthogonal axis in the resin film plane with respect to the light with a wavelength of 590 nm, nx, ny (however, nx ≧ ny), with a wavelength of 590 nm The refractive index nz in the thickness direction of the resin film with respect to the light beam was measured, and the thickness was determined from the following formula when the thickness of the resin film was d (nm). The measurement was performed once.
Thickness direction retardation Rth (nm) = d × {(nx + ny) / 2−nz}.

(6) Thickness variation With respect to the direction (TD) orthogonal to the film transport direction (MD), the portion excluding the edge portion of 50 mm was measured at 10 mm intervals using a Mitutoyo digital micrometer. It was calculated from the value and the minimum value.

a = (maximum value−total arithmetic average) / total arithmetic average × 100
b = (total arithmetic average−minimum value) / total arithmetic average × 100
Uneven thickness (%) = a + b.

(7) Photoelastic coefficient Photoelastic coefficient (10 ⁻¹² / Pa)
A sample having a short side of 1 cm and a long side of 7 cm was cut out. Using this sample, TRANSDUCER U3C1-5K manufactured by Shimadzu Corporation, a 1 cm / mm ² (9.81 × 10 ⁶ Pa) tension (F) was applied in the long side direction with 1 cm between the top and bottom. In this state, Re (nm) was measured using a polarizing microscope 5892 manufactured by Nikon Corporation. Sodium D line (589 nm) was used as a light source. These numerical values were applied to photoelastic coefficient = Re / (d × F) to calculate the photoelastic coefficient. The measurement was performed once.

(8) Residual Volatile Content Measurement is performed using a thermomass measuring device (TGA-50H) manufactured by Shimadzu Corporation and an analyzer thermal analyzer (TA-50) combined with a personal computer for data processing. It was. A resin film peeled from the support or about 7 mg of the resin film was set in a furnace, and the furnace was placed in a nitrogen atmosphere and heated from room temperature to 220 ° C. at a temperature rising rate of 10 ° C./min. From the obtained thermal mass curve, the residual volatile content of the resin film and the resin film was determined by the following formula. The measurement was performed twice per sample, and the average value was used as the remaining volatile matter. The measurement was performed once.
Residual volatile matter (parts by mass) = ((mass at 35 ° C.−mass at 200 ° C.) / Mass at 35 ° C.) × 100.

(9) Refractive Index, Refractive Index Difference Acetone is added to the resin film of the present invention and refluxed for 4 hours. This solution is centrifuged at 9,000 rpm for 30 minutes to dissolve acetone-soluble components (component (A)) and insoluble components. (Component (B)). These were dried under reduced pressure at 60 ° C. for 5 hours. Each of the obtained solids was press-molded at 250 ° C. to form a film having a thickness of 0.1 mm, and then the refractive index at 23 ° C. and 550 nm wavelength was measured with an Abbe refractometer (manufactured by Atago Co., Ltd., DR-M2). It was measured. In addition, the absolute value was used about the refractive index difference of (A) component and (B) component. The measurement was performed once.

(10) Weight average molecular weight (absolute molecular weight)
The obtained thermoplastic polymer was gel permeation chromatograph (pump: 515 type, manufactured by Waters, Inc.) equipped with a DAWN-DSP type multi-angle light scattering photometer (manufactured by Wyatt Technology) using dimethylformamide as a solvent. The weight average molecular weight (absolute molecular weight) was measured using TSK-gel-GMHXL (manufactured by Tosoh Corporation).

(11) Glass transition temperature Glass transition temperature (Tg)
Using a differential scanning calorimeter (DSC-7 manufactured by Perkin Elmer), the measurement was performed at a temperature increase rate of 20 ° C./min in a nitrogen atmosphere. The measurement was performed once. In addition, as a glass transition temperature (Tg), the midpoint glass transition temperature (Tmg) of JIS K7121-1987 is employ | adopted.

(12) Moisture absorption About 0.5 g of the film was sampled and heated for 3 hours at 120 ° C. for dehumidification, then the temperature was lowered to 25 ° C. so as not to absorb moisture, and the weight after the temperature reduction was 0.1 mg. Weigh accurately to unit (weight at this time is W0). Subsequently, it was left to stand in an atmosphere of 75 RH% at 25 ° C. for 48 hours, and then the weight was measured. This was defined as W1, and the moisture absorption rate was determined using the following equation.

  Moisture absorption rate (%) = ((W1-W0) / W0) × 100.

Example 1
In a stainless steel autoclave with a capacity of 5 liters and equipped with a baffle and a foudra-type stirring blade, a methyl methacrylate copolymer suspension (adjusted by the following method: 80 parts by mass of methyl methacrylate, manufactured by Nippon Shokubai Co., Ltd.) 20 parts by mass of ethyl α- (hydroxymethyl) acrylate (CAS No.10029-04-6, trade name: RHMA-E), 0.3 part by mass of potassium persulfate, and 1500 parts by mass of ion-exchanged water are charged into the reactor. The reactor is purged with nitrogen gas and maintained at 70 ° C. The reaction is continued until the monomer is completely converted to a polymer, and is obtained as an aqueous solution of methyl acrylate and acrylamide copolymer. A solution in which 0.05 part (used as a suspending agent) was dissolved in 165 parts of ion-exchanged water was supplied, stirred at 400 rpm, and the system was replaced with nitrogen gas. Next, the following mixed substances were added while stirring the reaction system, and the temperature was raised to 70 ° C. The time when the internal temperature reached 70 ° C. was set as the start of polymerization, and kept for 180 minutes to complete the polymerization. Thereafter, the reaction system was cooled, the polymer was separated, washed and dried according to the usual method to obtain a bead-shaped copolymer. The polymerization rate of this copolymer was 98%, and the weight average molecular weight was 130,000.

An additive (NaOCH ₃ ) was added thereto, and using a twin screw extruder (TEX30 (manufactured by Nippon Steel Co., Ltd., L / D = 44.5), while purging nitrogen at an amount of 10 L / min from the hopper part. Intramolecular cyclization reaction was performed at a screw rotation speed of 100 rpm, a raw material supply rate of 5 kg / h, and a cylinder temperature of 290 ° C. to obtain a pellet-shaped acrylic resin (A1), a lactone in 100 parts by mass of the acrylic resin (A1) The composition ratio of the ring unit was 20 parts by mass.
The obtained acrylic resin (A1) was dissolved in methylene chloride and taken on a glass plate on which a polyethylene terephthalate film (thickness: 100 μm) was fixed, and a uniform film was formed using a bar coater. This was heated at 50 ° C. for 10 minutes to obtain a self-supporting film. The obtained film is peeled off from the polyethylene terephthalate film and fixed to a metal frame, and further heated at 100 ° C. for 10 minutes, 120 ° C. for 20 minutes, 140 ° C. for 20 minutes, and 170 ° C. for 40 minutes to give a resin having a thickness of 102 μm A film was obtained.

Example 2
The unstretched film obtained in Example 1 was stretched 200% at 120 ° C. A retardation film having a thickness of 63 μm was obtained.

Example 3
Using the polymer (80% by mass) obtained in Example 1 and elastic particle AC2034 (20% by mass) manufactured by Gantz Kasei Co., Ltd. using a twin screw extruder (TEX30 (manufactured by Nippon Steel Co., Ltd., L / D = 44.5)). The mixture was kneaded at a screw speed of 150 rpm and a cylinder temperature of 280 ° C. to obtain a pellet-shaped resin, and the obtained resin was dissolved in methylene chloride and an unstretched film was obtained using a solution casting method.
Example 4 A suspension prepared by dissolving 0.1 g of ZONYL® UR (manufactured by DuPont) in 100 g of 2-butanone was applied to a stainless microlens mold (lens height 15 μm, period 50 μm) at 120 ° C. Dry for 5 minutes. Washed with dryness and acetone to remove excess ZONYL (R) UR. The polymer solution obtained in Example 1 was coated with a bar coater to a coating thickness of 200 μm, 50 ° C. for 10 minutes, 100 ° C. for 10 minutes, 120 ° C. for 20 minutes, 140 ° C. for 20 minutes, and 170 ° C. for 20 minutes. It heated and dried and the micro lens array with a film thickness of 51 micrometers was obtained. The obtained molded article had a lens height of 14.5 μm and a period of 50 μm.

Comparative Example 1
Polymethyl methacrylate [weight average molecular weight 120,000] 30 parts by mass, butyl acrylate-methyl methacrylate copolymer [butyl acrylate unit 20 parts by mass and methyl methacrylate unit 80 parts by mass, weight average molecular weight 300,000] 50 parts by mass 3 parts acrylic polymer (B2) containing 80 parts by mass of resin (A3) and spherical rubber elastic layer [innermost layer: copolymer of methyl methacrylate, intermediate layer: butyl acrylate as main component A soft rubber elastic body, outermost layer: polymethyl methacrylate, average particle diameter 300 nm] 20 parts by mass was melt-kneaded to obtain an acrylic resin composition, which was pelletized with a twin screw extruder. This resin pellet was extruded through a T-die (set temperature: 250 ° C.) using a 65 mmφ single screw extruder and cooled so that both surfaces were completely adhered to a polishing roll to obtain a resin film. This resin film was stretched in the width direction using a uniaxial tenter at a stretching temperature of 100 ° C., a stretching ratio of 3 times, and a stretching speed of 8.6 m / min to obtain a resin film.

  The resin film thus obtained had a small number of folding resistances, and cracks occurred during die cutting. In addition, the thermal deformation temperature is low and the thermal dimensional stability is also poor. Furthermore, haze is also bad and it is not suitable as an optical filter. The characteristics of the film are as follows.

Thermal deformation temperature (° C.): 85
Elongation at break (%): 25
Glass transition temperature (Tg): 90
Total light transmittance (%): 90
Haze (%): 5

  The resin film of this invention can be utilized suitably for display material uses, such as a polarizer protective film and retardation film.

Claims (10)

A resin film containing a ring structure represented by the following structural formula (1) and satisfying the following (i) to (v).
(I) When the film thickness is d (μm) and the retardation in the film surface with respect to light having a wavelength of 550 nm is R (550) (nm), the following formula (a) is satisfied: −0.001 <R ( 550) / d <0.001 (A)
(Ii) When the film thickness is d (μm) and the phase difference in the film plane with respect to light having a wavelength of 590 nm is Rth (590) (nm), the following expression (2) is satisfied: −0.007 <Rth ( 590) / d <0.007 (i)
(Iii) Film thickness d (μm) is 1 to 100 μm
(Iv) Glass transition temperature is 110 ° C. or higher (v) Film thickness unevenness is 5% or less

R ^{1 to} R ³ : hydrogen or a hydrocarbon group having 1 to 10 carbon atoms 2. The resin film according to claim 1, wherein retardations R (450), R (650), and R (753) in the film plane with respect to light having wavelengths of 450, 650, and 753 nm satisfy the following formulas (U) and (E). .
R (450) / R (650) ≧ 1.00 (U)
R (650) / R (753) ≦ 1.00 (E) 3. The resin film according to claim 1, wherein the photoelastic coefficient for light having a wavelength of 550 nm is −2 × 10 ⁻¹² / Pa or more and 2 × 10 ⁻¹² / Pa or less. The resin film according to any one of claims 1 to 4, which has an elongation at break of 5% or more. The resin film according to any one of claims 1 to 4, wherein the main material is a mixture of 100 parts by mass of a resin (A) containing a ring structure and 0.1 to 50 parts by mass of elastic particles (B). The manufacturing method characterized by manufacturing the resin film in any one of Claims 1-5 using a solution casting method. The member for display materials which has the resin film in any one of Claims 1-5. A polarizing plate protective film comprising the resin film according to claim 1. A film having R (550) / d of 0.001 or more using the resin film according to any one of claims 1 to 5 as an intermediate. A prism sheet, a lens and / or a screen, wherein at least one surface of the resin film according to claim 1 has an arbitrary shape.