JP5493285B2 - Optical film - Google Patents

Description

  The present invention relates to an optical film containing an ultraviolet absorber. Specifically, the present invention relates to an optical film which is formed using an acrylic resin and a cellulose ester resin as main components and contains a specific ultraviolet absorber.

  The optical film used for the protective film for polarizing plates uses an ultraviolet absorber for the purpose of protecting the polarizer and liquid crystal from ultraviolet rays. In particular, it is essential for the protective film on the viewing side of the liquid crystal panel and the protective film on the backlight side.

  This UV absorber may have poor compatibility with the resin used for the film, and the UV absorber may bleed out when the film is left in high temperature and high humidity.

  The compatibility between the resin and the UV absorber is determined by the combination, but there are UV absorbers that are compatible only with cellulose esters and UV absorbers that are compatible only with acrylic resins, and there are cases where the selection range of UV absorbers is narrow. (For example, see Patent Documents 1 to 4).

On the other hand, the acrylic resin film has excellent transparency and is suitable as an optical film. However, if the film is simply thinned to meet the demand for high performance and thin film, it can sufficiently cut ultraviolet rays. First, the amount of the UV absorber must be increased by the amount of the thin film. However, since the compatibility of the UV absorber is insufficient, the UV absorber adheres to the peeling roll and the transport roll in the optical film manufacturing process, causing a failure and greatly reducing productivity. was there. Further, when the amount of the ultraviolet absorber is increased, the haze is increased, and the optical film has a problem that the performance such as transmittance, adhesion, bleed out resistance and the like deteriorates.
JP-A-6-130226 Japanese Unexamined Patent Publication No. 7-11056 JP-A-6-148430 JP 2002-47357 A

  The present invention has been made in view of the above-mentioned problems, and the problem to be solved is an optical film containing an ultraviolet absorber, which has improved performance such as haze, transmittance, adhesion, bleed-out resistance and the like. It is to provide an optical film.

  The above-mentioned problem according to the present invention is solved by the following means.

  1. The acrylic resin and the cellulose ester resin are contained in a compatible state at a mass ratio of 95: 5 to 30:70, the weight average molecular weight (Mw) of the acrylic resin is 80000 or more, and the acyl group of the cellulose ester resin The total substitution degree is 2.0 to 3.0, the substitution degree of the acyl group having 3 to 7 carbon atoms is 1.2 to 3.0, and the weight average molecular weight Mw of the cellulose ester resin is 75000 or more. An optical film characterized by comprising an ultraviolet absorber.

  2. 2. The optical film as described in 1 above, which contains an ultraviolet absorbing polymer as the ultraviolet absorber.

  3. 3. The optical film as described in 1 or 2 above, which contains at least one compound selected from the compounds represented by the following general formulas (UVA1) to (UVA3) as the ultraviolet absorber.

(In the general formulas (UVA1) to (UVA3), R ₁ and R ₂ each represent a substituent, and X represents —COO—, —OCO—, —NR ₁₁ CO—, —CONR ₁₁ —, —O—. , —NR ₁₂ R ₁₃ —, —SO ₂ NR ₁₄ —, —NR ₁₄ SO ₂ —, —S—, or —SO ₂ —, wherein L ₁ is a divalent linking group, and L ₂ is a trivalent linking group. Group, L ₃ represents a tetravalent linking group, R ₁₁ , R ₁₂ , R ₁₃ and R ₁₄ each represents a hydrogen atom, an alkyl group or an aryl group, p is an integer of 0 to 3, q is Represents an integer of 0 to 4)
4). 4. The optical film according to any one of 1 to 3, wherein the cellulose ester resin has a total substitution degree of acyl groups other than 3 to 7 carbon atoms of 1.3 or less.

  5. 5. The optical film according to any one of 1 to 4, wherein the cellulose ester resin has a total substitution degree of acyl groups having 3 to 7 carbon atoms of 2.00 or more.

  6). 6. The optical film as described in any one of 1 to 5 above, wherein the total degree of substitution of acyl groups of the cellulose ester resin is 2.5 to 3.0.

  7). The optical film according to any one of 1 to 6, wherein the acrylic resin is an acrylic resin having 50 to 99% by mass of a methyl methacrylate unit in the molecule.

  8). The optical film according to any one of 1 to 7, wherein a mass ratio of the acrylic resin to the cellulose ester resin is in a range of 95: 5 to 50:50.

  9. The weight average molecular weight (Mw) of the said acrylic resin exists in the range of 80000-1 million, The optical film as described in any one of Claims 1-8 characterized by the above-mentioned.

  10. 10. The optical film as described in any one of 1 to 9 above, wherein the cellulose ester resin has a weight average molecular weight (Mw) in the range of 75,000 to 300,000.

  11. The said optical film contains 0.5-30 mass% acrylic particle with respect to the gross mass of resin which comprises the said optical film, The optical as described in any one of said 1-10 characterized by the above-mentioned. the film.

  12 The optical film according to any one of 1 to 10, which has a thickness of 20 to 200 μm and is used as a polarizing plate protective film.

  By the means of the present invention, an optical film containing an ultraviolet absorber and having improved performance such as haze, transmittance, adhesion, bleed-out resistance and the like can be provided.

  That is, by mixing the acrylic resin and the cellulose ester resin in a compatible state, it is possible to use an ultraviolet absorber compatible with either of them.

  Furthermore, bleeding out can be significantly reduced by using a resin having a specific molecular weight and substitution degree. Moreover, the ultraviolet absorber adheres to the peeling roll and the transport roll in the manufacturing process of the optical film, which can cause a failure and greatly reduce productivity.

  Furthermore, the adhesion of the hard coat layer can be improved by adding an ultraviolet absorber.

  In general, since an ultraviolet (UV) curable resin is used for the hard coat layer, UV light is irradiated when the hard coat layer is cured. When this ultraviolet ray is absorbed by the ultraviolet absorbent in the optical film, heat is generated on the surface of the optical film, and the temperature at the interface with the hard coat layer increases. It is considered that the adhesiveness improves as the curing reaction of the hard coat layer further proceeds due to this temperature rise.

  The optical film of the present invention contains an acrylic resin and a cellulose ester resin in a compatible state at a mass ratio of 95: 5 to 30:70, and the acrylic resin has a weight average molecular weight (Mw) of 80000 or more, The total substitution degree of the acyl group of the cellulose ester resin is 2.0 to 3.0, the substitution degree of the acyl group having 3 to 7 carbon atoms is 1.2 to 3.0, and the weight of the cellulose ester resin The average molecular weight Mw is 75000 or more and contains an ultraviolet absorber. This feature is a technical feature common to the inventions according to claims 1 to 12.

  An embodiment of the present invention is preferably an embodiment containing an ultraviolet absorbing polymer as the ultraviolet absorber. Moreover, it is also preferable to contain at least one compound selected from compounds represented by the general formulas (UVA1) to (UVA3) as the ultraviolet absorber.

  In this invention, it is preferable that it is an aspect whose sum total of the substitution degree of acyl groups other than C3-C7 of the said cellulose ester resin is 1.3 or less. Moreover, it is preferable that the sum total of the substitution degree of a C3-C7 acyl group of the said cellulose ester resin is 2.00 or more. Furthermore, it is preferable that the total substitution degree of the acyl group of the said cellulose ester resin is 2.5-3.0.

  Moreover, in this invention, it is preferable that the said acrylic resin is an aspect which is an acrylic resin which has 50-99 mass% of methyl methacrylate units in a molecule | numerator.

  Furthermore, the mass ratio of the acrylic resin and the cellulose ester resin is more preferably in the range of 95: 5 to 50:50. Especially preferably, it exists in the range of 90: 10-60: 40.

  The weight average molecular weight (Mw) of the acrylic resin is more preferably in the range of 80,000 to 1,000,000, and particularly preferably in the range of 150,000 to 400,000.

  On the other hand, the weight average molecular weight (Mw) of the cellulose ester resin is preferably in the range of 75,000 to 300,000, particularly preferably in the range of 100,000 to 240,000.

  In this invention, it is preferable that it is an aspect containing 0.5-30 mass% acrylic particle with respect to the gross mass of resin which comprises the said optical film. Moreover, it is preferable that a film thickness is 20-200 micrometers and it is used as a polarizing plate protective film.

  Hereinafter, the present invention, its components, and the best mode and mode for carrying out the present invention will be described in detail.

<acrylic resin>
The acrylic resin used in the present invention includes a methacrylic resin. Although it does not restrict | limit especially as resin, What consists of 50-99 mass% of methyl methacrylate units and 1-50 mass% of other monomer units copolymerizable with this is preferable.

  Other monomers that can be copolymerized include alkyl methacrylates having 2 to 18 carbon atoms, alkyl acrylates having 1 to 18 carbon atoms, acrylic acid, methacrylic acid, and the like. Saturated acids, maleic acids, fumaric acids, unsaturated divalent carboxylic acids such as itaconic acid, aromatic vinyl compounds such as styrene, α-methylstyrene, and nucleus-substituted styrene, α, β- such as acrylonitrile, methacrylonitrile, etc. Examples thereof include unsaturated nitrile, maleic anhydride, maleimide, N-substituted maleimide, glutaric anhydride, and the like. These may be used alone or in combination of two or more.

  Among these, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, s-butyl acrylate, 2-ethylhexyl acrylate, and the like are preferable from the viewpoint of thermal decomposition resistance and fluidity of the copolymer. n-Butyl acrylate is particularly preferably used.

  The acrylic resin used in the optical film of the present invention preferably has a weight average molecular weight (Mw) of 80,000 to 1,000,000 from the viewpoint of mechanical strength as a film and fluidity when producing the film.

  The weight average molecular weight of the acrylic resin of the present invention can be measured by gel permeation chromatography. The measurement conditions are as follows.

Solvent: Methylene chloride Column: Shodex K806, K805, K803G (Used by connecting three Showa Denko Co., Ltd.)
Column temperature: 25 ° C
Sample concentration: 0.1% by mass
Detector: RI Model 504 (manufactured by GL Sciences)
Pump: L6000 (manufactured by Hitachi, Ltd.)
Flow rate: 1.0ml / min
Calibration curve: Standard polystyrene STK standard polystyrene (manufactured by Tosoh Corp.) Mw = 2,800,000-500 calibration curves with 13 samples were used. The 13 samples are preferably used at approximately equal intervals.

  There is no restriction | limiting in particular as a manufacturing method of the acrylic resin in this invention, You may use any well-known methods, such as suspension polymerization, emulsion polymerization, block polymerization, or solution polymerization. Here, as a polymerization initiator, a normal peroxide type and an azo type can be used, and a redox type can also be used. Regarding the polymerization temperature, suspension or emulsion polymerization may be performed at 30 to 100 ° C, and bulk or solution polymerization may be performed at 80 to 160 ° C. Furthermore, in order to control the reduced viscosity of the produced copolymer, polymerization can be carried out using alkyl mercaptan or the like as a chain transfer agent.

  With this molecular weight, both heat resistance and brittleness can be achieved.

  A commercially available thing can also be used as an acrylic resin of this invention. For example, Delpet 60N, 80N (Asahi Kasei Chemicals Co., Ltd.), Dialal BR52, BR80, BR83, BR85, BR88 (Mitsubishi Rayon Co., Ltd.), KT75 (Electric Chemical Co., Ltd.), etc. are mentioned. .

<Cellulose ester resin>
The cellulose ester resin according to the present invention has an acyl group total substitution degree (T) of 2.00 to 3.00 and a carbon number of 3, particularly from the viewpoint of improvement in brittleness and transparency when mixed with an acrylic resin. The substitution degree of the acyl group of ˜7 is preferably 1.2 to 3.0. That is, the cellulose ester resin is a cellulose ester resin substituted with an acyl group having 3 to 7 carbon atoms. Specifically, propionyl, butyryl and the like are preferably used, and a propionyl group is particularly preferably used.

  When the total substitution degree of the acyl group of the cellulose ester resin is less than 2.0, that is, when the residual degree of the hydroxyl groups at the 2, 3, and 6 positions of the cellulose ester molecule is more than 1.0, the acrylic resin (A ) And the haze is a problem. Moreover, even if the total substitution degree of the acyl group is 2.0 or more, if the substitution degree of the acyl group having 3 to 7 carbon atoms is less than 1.2, still sufficient compatibility cannot be obtained, Brittleness will decrease. For example, even when the total substitution degree of the acyl group is 2.0 or more, the substitution degree of the acyl group having 2 carbon atoms, that is, the acetyl group is high, and the substitution degree of the acyl group having 3 to 7 carbon atoms is 1. When it is less than 2, the compatibility is lowered and the haze is increased. Even when the total substitution degree of the acyl group is 2.0 or more, the substitution degree of the acyl group having 8 or more carbon atoms is high, and the substitution degree of the acyl group having 3 to 7 carbon atoms is less than 1.2. In such a case, the brittleness is lowered and desired characteristics cannot be obtained.

The acyl substitution degree of the cellulose ester resin of the present invention is that the total substitution degree (T) is 2.0 to 3.0, and the substitution degree of the acyl group having 3 to 7 carbon atoms is 1.2 to 3.0. If there is no problem,
It is preferable that the total substitution degree of acyl groups having 3 to 7 carbon atoms, that is, acetyl groups or acyl groups having 8 or more carbon atoms is 1.3 or less.

  In the present application, the “acyl group” is meant to include those further having a substituent. However, the carbon number of the acyl group includes a substituent of the acyl group.

  When the said cellulose ester resin has an aromatic acyl group as a substituent, it is preferable that the number of the substituents X substituted to an aromatic ring is 0-5. Also in this case, it is necessary to pay attention so that the substitution degree of the acyl group having 3 to 7 carbon atoms including the substituent is 1.2 to 3.0. For example, since the benzyl group has 7 carbon atoms, when it has a substituent containing carbon, the benzyl group has 8 or more carbon atoms and is not included in the acyl group having 3 to 7 carbon atoms. Become.

  Further, when the number of substituents substituted on the aromatic ring is 2 or more, they may be the same or different from each other, but they may be linked together to form a condensed polycyclic compound (for example, naphthalene, indene, indane, phenanthrene, quinoline). , Isoquinoline, chromene, chroman, phthalazine, acridine, indole, indoline, etc.).

  In the said cellulose ester resin, having a structure which has at least 1 sort (s) of a substituted or unsubstituted C3-C7 aliphatic acyl group is used as a structure used for the cellulose resin of this invention.

  The substitution degree of the cellulose ester resin of the present invention is such that the total substitution degree (T) of the acyl group is 2.00 to 3.00, and the substitution degree of the acyl group having 3 to 7 carbon atoms is 1.2 to 3.0. is there.

  Moreover, it is a preferable structure that the sum total of the substitution degree of other than an acyl group having 3 to 7 carbon atoms, that is, an acetyl group and an acyl group having 8 or more carbon atoms is 1.3 or less.

  The cellulose ester resin according to the present invention is preferably at least one selected from cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate benzoate, cellulose propionate, and cellulose butyrate, particularly cellulose acetate propionate. Nate and cellulose propionate are more preferable.

  Among these, particularly preferable cellulose ester resins are cellulose acetate propionate and cellulose acetate butyrate, and those having an acyl group having 3 or 4 carbon atoms as a substituent are preferable.

  The portion not substituted with an acyl group usually exists as a hydroxyl group. These can be synthesized by known methods.

  In addition, the substitution degree of an acetyl group and the substitution degree of other acyl groups are obtained by a method prescribed in ASTM-D817-96.

  The weight average molecular weight (Mw) of the cellulose ester resin of the present invention is 75000 or more, particularly from the viewpoint of improvement in compatibility with acrylic resin and brittleness, preferably in the range of 75,000 to 300,000, and in the range of 100,000 to 240,000. It is more preferable that it is within the range of 160000 to 240000.

  In the optical film of the present invention, the acrylic resin and the cellulose ester resin are contained in a compatible state at a mass ratio of 95: 5 to 30:70, preferably 95: 5 to 50:50, more preferably. 90: 10-60: 40.

  In the optical film of the present invention, the acrylic resin and the cellulose ester resin need to be contained in a compatible state. The physical properties and quality required for an optical film are achieved by supplementing each other by dissolving different resins.

  Whether the acrylic resin and the cellulose ester resin are in a compatible state can be determined, for example, based on the glass transition temperature Tg.

  For example, when the glass transition temperatures of the two resins are different, when the two resins are mixed, there are two or more glass transition temperatures of the mixture because there is a glass transition temperature of each resin. When the resins are compatible, the glass transition temperature specific to each resin disappears, and the glass transition temperature of the compatible resin is obtained by becoming one glass transition temperature.

  The glass transition temperature referred to here is an intermediate value determined according to JIS K7121 (1987) using a differential scanning calorimeter (DSC-7 model manufactured by Perkin Elmer) at a temperature rising rate of 20 ° C./min. The point glass transition temperature (Tmg).

  The acrylic resin and the cellulose ester resin are each preferably an amorphous resin, and either one may be a crystalline polymer or a partially crystalline polymer. It is preferable that the non-crystalline resin is formed by the compatibility between the cellulose ester resin and the cellulose ester resin.

  After the weight average molecular weight (Mw) of the acrylic resin, the weight average molecular weight (Mw) of the cellulose ester resin, and the degree of substitution in the optical film of the present invention are separated using the difference in solubility in the solvent of both resins. , Obtained by measuring each. When fractionating the resin, it is possible to extract and separate the soluble resin by adding a compatible resin in a solvent that is soluble only in either one. At this time, heating operation or reflux is performed. May be. A combination of these solvents may be combined in two or more steps to separate the resin. The dissolved resin and the resin remaining as an insoluble matter are filtered off, and the solution containing the extract can be separated by an operation of evaporating the solvent and drying. These fractionated resins can be identified by general structural analysis of polymers. When the optical film of the present invention contains a resin other than an acrylic resin or a cellulose ester resin, it can be separated by the same method.

  If the weight average molecular weights (Mw) of the compatible resins are different, the high molecular weight substances are eluted earlier by gel permeation chromatography (GPC), and the lower molecular weight substances are eluted after a longer time. Therefore, it can be easily fractionated and the molecular weight can be measured.

  In addition, the molecular weight of the compatible resin is measured by GPC, and at the same time, the resin solution eluted every time is separated, the solvent is distilled off, and the structure analysis of the dried resin is quantitatively performed. By detecting the resin composition for each fraction, each compatible resin can be specified. By measuring the molecular weight distribution of each of the resins separated in advance based on the difference in solubility in a solvent by GPC, it is possible to detect each of the compatible resins.

  In the present invention, it is necessary that the acrylic resin and the cellulose ester resin are mixed with each other within the scope of the present invention.

  For example, the process of obtaining a mixed resin by polymerizing a precursor of an acrylic resin such as a monomer, dimer or oligomer with a cellulose ester resin is complicated, and the resin produced by this method is The control of the reaction is difficult. In addition, when a resin is synthesized by such a method, graft polymerization, cross-linking reaction or cyclization reaction often occurs, and the resin is not dissolved in a solvent or often cannot be melted by heating, so that the optical film can be stabilized. It is difficult to use as a resin to be manufactured. Therefore, the resin obtained by such a method does not correspond to a resin containing the acrylic resin and the cellulose ester resin of the present invention in a compatible state.

  Unless the function as an optical film is impaired, the optical film of this invention may contain resin and additives other than an acrylic resin and a cellulose-ester resin, and may be comprised.

  When the resin other than the acrylic resin and the cellulose ester resin is contained, the resin to be added may be mixed without being dissolved even if it is in a compatible state.

  The total mass of the acrylic resin and the cellulose ester resin in the optical film of the present invention is preferably 55% by mass or more of the optical film, more preferably 60% by mass or more, and particularly preferably 70% by mass or more. .

  When using a resin or additive other than the acrylic resin and the cellulose ester resin, it is preferable to adjust the addition amount within a range that does not impair the function of the optical film of the present invention.

(UV absorber)
The optical film of the present invention is characterized by containing an ultraviolet absorber. In the present invention, various conventionally known ultraviolet absorbers can be used, but it is preferable to contain an ultraviolet absorbing polymer as the ultraviolet absorber. Moreover, it is preferable to contain at least 1 type of compound selected from the compound represented by the said general formula (UVA1)-(UVA3) as a ultraviolet absorber.

  Hereinafter, specific examples of preferable ultraviolet absorbers will be described.

<Ultraviolet absorbing polymer>
Examples of the ultraviolet absorbing polymer that can be suitably used as the ultraviolet absorber include the following examples.

  Ultraviolet-absorbing polymer containing a repeating unit represented by the following general formula (1):

(Wherein J ₁ represents —O—, —NR ₁ —, —S—, —SO—, —SO ₂ —, —POO—, —CO—, —COO—, —NR ₂ CO—, —NR) _{3 COO -, - NR 4 CONR} 5 -, - OCO -, - OCONR 6 -, - CONR 7 -, - NR 8 SO -, - NR 9 SO 2 -, - SONR 10 -, - SO 2 NR 11 - the represents, R ₁ to R ₁₁ represents a hydrogen atom, an alkyl group, .Sp ₁ representing the aryl group represents a divalent linking group, a halogen atom, which may have a substituent. However, ultraviolet absorbent to Sp ₁ The group is bonded directly or through a spacer, or a part or all of the ultraviolet absorbing group forms part of the polymer main chain.)
Ultraviolet absorbing polymer containing a repeating unit represented by the following general formula (2):

(In the formula, J ₂ and J ₃ have the same meaning as J ₁ in the general formula (1), and J ₂ and J ₃ may be the same or different. Sp ₂ and Sp ₃ are the general formulas. (1) It has the same meaning as Sp ₁ and Sp ₂ and Sp ₃ may be the same or different from each other, but at least one of Sp ₂ and Sp ₃ has an ultraviolet absorbing group directly or a spacer. Or at least one of Sp ₂ and Sp ₃ , part or all of the ultraviolet absorbing group forms part of the polymer main chain.)
Ultraviolet absorbing polymer containing a repeating unit having an ultraviolet absorbing group represented by the following general formula (3):

(In the formula, R _{12 to} R ₂₅ each represent a hydrogen atom, a halogen atom, or a substituent. In R _{12 to} R ₂₅ , adjacent ones may be bonded to each other to form a ring. The UV-absorbing group represented by the general formula (3) is bonded to the polymer main chain directly or via a spacer at any site, or a part or all of the UV-absorbing group is a polymer main chain. It forms part of the chain.)
An ultraviolet absorbing polymer containing a repeating unit having an ultraviolet absorbing group represented by the following general formula (4):

(Wherein R ₂₆ and R ₂₇ each represent an alkyl group having 1 to 10 carbon atoms, R ₂₈ , R ₂₉ and R ₃₀ each represents an alkyl group, an alkoxy group, an alkylthio group and an amino group, and X and Y are Each represents an electron-withdrawing group, provided that R _{26 to} R ₃₀ and X and Y may have a halogen atom or a substituent, and these are connected to each other to form a 5- or 6-membered ring; However, the UV-absorbing group represented by the general formula (4) is bonded to the polymer main chain directly or via a spacer at any site, or a part of the UV-absorbing group or All form part of the polymer backbone.)
Ultraviolet absorbing polymer containing a repeating unit having an ultraviolet absorbing group represented by the following general formula (5):

(In the formula, R _{66 to} R ₇₁ each represent a hydrogen atom, a halogen atom, or a substituent. X and Y have the same meanings as X and Y in formula (4), provided that in formula (5) The UV-absorbing group represented is bonded to the polymer main chain directly or via a spacer at any position, or part or all of the UV-absorbing group forms part of the polymer main chain. doing.)
Ultraviolet-absorbing polymer containing a repeating unit represented by the following general formula (6):

(In the formula, R ₃₁ and R ₃₂ represent a hydrogen atom, a halogen atom, and a substituent, l represents 0, 1, 2, 3 and m represents 0, 1, 2, 3, 4; Or R ₃₁ may be the same as or different from each other when 3, and R ₃₂ may be the same or different from each other when m is 2, 3 or 4. J ₄ is * —O—, * -NR _1- , * -S-, * -SO-, * -SO _2- , * -POO-, * -CO-, * -COO-, * -NR ₂ CO-, * -NR ₃ COO- _{, * - NR 4 CONR 5 -} , * - OCO -, * - OCONR 6 -, * - CONR 7 -, * - NR 8 SO -, * - NR 9 SO 2 -, * - SONR 10 -, * - SO ₂ NR ₁₁ -. represents the proviso asterisk has the same meaning as .R ₁ ~R ₁₁ R ₁ ~R ₁₁ of the general formula (1) indicating that it is connected to the UV absorbing group in *. Sp ₄ is one (It is synonymous with Sp _{1 in the} general formula (1).)
Ultraviolet-absorbing polymer containing a repeating unit represented by the following general formula (7):

(In the formula, R ₃₃ and R ₃₄ represent a hydrogen atom, a halogen atom, and a substituent, s represents 0, 1, 2, 3, 4, o represents 0, 1, 2, 3, and s represents 2) when 3 or 4, each other R ₃₃ may be the same as or different from each other, when o is 2 or 3, each other R ₃₄ is optionally the same as or different from each other .J ₅ is, * - o-, * -NR _1- , * -S-, * -SO-, * -SO _2- , * -POO-, * -CO-, * -COO-, * -NR ₂ CO-, * -NR ₃ COO- _{, * - NR 4 CONR 5 -} , * - OCO -, * - OCONR 6 -, * - CONR 7 -, * - NR 8 SO -, * - NR 9 SO 2 -, * - SONR 10 -, * - SO ₂ NR ₁₁ -. represents the proviso asterisk has the same meaning as .R ₁ ~R ₁₁ R ₁ ~R ₁₁ of the general formula (1) indicating that it is connected to the UV absorbing group in *. Sp ₅ is one (It is synonymous with Sp _{1 in the} general formula (1).)
Ultraviolet absorbing polymer which is a copolymer derived from compounds represented by the following general formulas (8) and (9):

(In the formula, R _{35 to} R ₃₉ each represent a hydrogen atom, a halogen atom, or a substituent, and Sp ₆ has the same meaning as Sp _{1 in} formula (1). Q is 0, 1, 2, 3, 4, r represents 0, 1, 2, 3. When q is 2, 3 or 4, R ₃₅ may be the same or different from each other, and when r is 2 or 3, R ₃₆ are They may be the same or different.)
In the general formula (1), J ₁ represents —O—, —NR ₁ —, —S—, —SO—, —SO ₂ —, —POO—, —CO—, —COO—, —NR ₂ CO—, _{-NR 3 COO -, - NR 4} CONR 5 -, - OCO -, - OCONR 6 -, - CONR 7 -, - NR 8 SO -, - NR 9 SO 2 -, - SONR 10 -, - SO 2 NR 11 — Represents —O—, —S—, —COO—, —OCO—, —NR ₂ CO—, and —CONR ₇ —. R _{1 to} R ₁₁ are each a hydrogen atom, an alkyl group (for example, a methyl group, an ethyl group, an isopropyl group, a hydroxyethyl group, a methoxymethyl group, a trifluoromethyl group, a t-butyl group), an aryl group (for example, a phenyl group). Group, naphthyl group, p-tolyl group, p-chlorophenyl group and the like). The alkyl group and aryl group may be substituted or unsubstituted.

Sp ₁ represents a divalent linking group and is not particularly limited, but preferably includes a divalent linking group containing an alkylene group or an arylene group, more preferably an alkylene group having 1 to 10 carbon atoms, or a carbon number. 4 to 10 arylene groups. These divalent linking groups may have a halogen atom or a substituent. Examples of the substituent include an alkyl group (for example, methyl group, ethyl group, isopropyl group, hydroxyethyl group, methoxymethyl group, trifluoromethyl group, t-butyl group), aryl group (for example, phenyl group, naphthyl group, p -Tolyl group, p-chlorophenyl group etc.), acyl group (eg acetyl group, propanoyl group, butyroyl group etc.), sulfonyl group (eg methanesulfonyl group, butanesulfonyl group, phenylsulfonyl group etc.), alkoxy group (eg methoxy group) Ethoxy group, isopropoxy group, n-butoxy group, etc.), aryloxy group (eg, phenoxy group, etc.), alkylthio group (eg, methylthio group, ethylthio group, n-butylthio group, etc.), arylthio group (eg, phenylthio group, etc.) , Amino group, alkylamino group (for example, methylamino group) , Ethylamino group, dimethylamino group etc.), arylamino group (eg phenylamino group etc.), acylamino group (eg acetylamino group, propionylamino group etc.), hydroxyl group, cyano group, carbamoyl group (eg methylcarbamoyl group, Ethylcarbamoyl group, dimethylcarbamoyl group, etc.), sulfamoyl group (eg, ethylsulfamoyl group, dimethylsulfamoyl group, etc.), sulfonamide group, acyloxy group, oxycarbonyl group, sulfonylamino group (eg, methanesulfonylamino group, benzene) Sulfonylamino groups, etc.), ureido groups (eg, 3-methylureido group, 3,3-dimethylureido group, 1,3-dimethylureido group, etc.), sulfamoylamino groups (dimethylsulfamoylamino group, etc.), alkoxy Carbo Group (eg methoxycarbonyl group, ethoxycarbonyl group etc.), aryloxycarbonyl group (eg phenoxycarbonyl group etc.), nitro group, imide group (eg phthalimide group etc.), heterocyclic group (eg pyridyl group, benzimidazolyl group etc.) , A benzthiazolyl group, a benzoxazolyl group, etc.), preferably a hydrogen atom, a halogen atom, an alkyl group, an acylamino group, a carbamoyl group, an acyloxy group, or an oxycarbonyl group.

However, an ultraviolet-absorbing group is bonded to Sp ₁ directly or via a spacer, or a part or all of the ultraviolet-absorbing group forms part of the polymer main chain.

The spacer here may be any divalent linking group, but is preferably a divalent linking group containing a substituted or unsubstituted alkylene group, a substituted or unsubstituted arylene group, or -O. —, —NR ₄ O—, —S—, —SO—, —SO ₂ —, —POO—, —CO—, —COO—, —NR ₄₁ CO—, —NR ₄₂ COO—, —NR ₄₃ CONR ₄₄ Examples thereof include a divalent linking group composed of a combination of any one of —, —OCO—, —OCONR ₄₅ —, and —CONR ₄₆ — and a substituted or unsubstituted alkylene group, or a substituted or unsubstituted arylene group.

Here, R _{41 to} R ₄₆ each represent a hydrogen atom, a hydroxyl group, an alkyl group, or an aryl group. Each of the alkyl group and the aryl group may have a plurality of substituents, and examples of the substituent include those exemplified as examples of the substituent that Sp ₁ in the general formula (1) can take.

  The UV-absorbing group in the present invention is a group that has extremely large spectral absorption at 380 nm and hardly absorbs visible light of 420 nm or more, and any group having such properties may be used. Can include ultraviolet absorbing groups obtained by removing one or more hydrogen atoms from the compounds represented by the following general formulas (10) to (18).

Each of the ultraviolet absorbing groups of the present invention may be substituted with one or more halogen atoms and substituents. Examples of the substituent, those mentioned as examples of the substituent Sp ₁ in the general formula (1), and the like. Of course, the repeating units represented by the general formulas (1) and (2), the UV-absorbing groups represented by the general formulas (3) to (5), and the repeating units represented by the general formulas (6) and (7). You may have an ultraviolet absorptive group in a unit.

In the general formulas (10) to (18), R _{55 to} R ₆₅ represent a hydrogen atom, a halogen atom, or a substituent. Examples of the substituent include those of the Sp ₁ in general formula (1). In general formula (12), R ₅₅ and R ₅₆ are preferably a hydrogen atom and an alkyl group. In general formula (15), R ₅₇ , R ₅₈ and R ₅₉ are a hydrogen atom and an alkyl group. In the group, aryl group, and general formula (17), examples of R ₆₀ and R ₆₁ include an alkyl group.

Further, R _{62 to} R ₆₅ in the general formulas (17) and (18) are preferably an alkyl group, an aryl group, an alkoxy group, an alkylthio group, and an amino group. In the general formula (15), X represents a methylene or chalcogen atom, preferably a sulfur atom.

In the general formulas (17) and (18), EWG _{1 to} EWG ₄ represent an electron-withdrawing group, and examples of the electron-withdrawing group include an acylamino group (for example, an acetylamino group, a propionylamino group, etc.), a sulfonylamino group. (Eg methanesulfonylamino group, benzenesulfonylamino group etc.), sulfamoylamino group (eg dimethylsulfamoylamino group etc.), carbamoyl group (eg methylcarbamoyl group, ethylcarbamoyl group, dimethylcarbamoyl group etc.), sulfamoyl group (Eg ethylsulfamoyl group, dimethylsulfamoyl group etc.), alkoxycarbonyl group (eg methoxycarbonyl group, ethoxycarbonyl group etc.), aryloxycarbonyl group (eg phenoxycarbonyl group etc.), sulfonyl group (eg methanesulfonyl group etc.) Butanesulfonyl group, phenylsulfonyl group, etc.), acyl groups (for example, acetyl group, propanoyl group, butyroyl group, etc.), nitro groups, substituents such as cyano groups, and halogen atoms, preferably cyano groups, acyl groups , A sulfonyl group, an alkoxycarbonyl group, and a carbamoyl group.

However, EWG ₁ and EWG ₂ in the general formula (17) and EWG ₃ and EWG _{4 in} the general formula (18) need not be both electron-withdrawing groups, and if either one is an electron-withdrawing group, good. Further, in the general formula (17), R _{60 to} R ₆₄ , EWG ₁ , EWG ₂ , and in the general formula (18), EWG ₃ , EWG ₄ and R ₆₅ may be connected to each other to form a 5- or 6-membered ring. .

In the general formula (2), J ₂ and J ₃ have the same meaning as J ₁ in the general formula (1), and J ₂ and J ₃ may be the same as or different from each other. Sp ₂ and Sp ₃ are synonymous with Sp ₁ in the general formula (1), and Sp ₂ and Sp ₃ may be the same as or different from each other. A UV-absorbing group is bonded to at least one of Sp ₂ and Sp ₃ directly or via a spacer, or at least one of Sp ₂ and Sp is a part or all of the UV-absorbing group of the polymer main chain. Forming part. Specific examples of the linking group and substituent of Sp ₂ and Sp ₃ are the same as Sp ₁ in the general formula (1).

  Examples of the UV-absorbing group include the same groups as those listed as the UV-absorbing group in the general formula (1). Similarly, examples of the spacer include those listed as the spacer in the general formula (1).

In the general formula (3), R _{12 to} R ₂₅ each have a hydrogen atom, a halogen atom, and a substituent. Examples of the substituent include those of the Sp ₁ in general formula (1). And the like. R _{12 to} R ₂₅ may be the same or different. Further, in R _{12 to} R ₂₅ , adjacent ones may be bonded to each other to form a ring. The UV-absorbing group represented by the general formula (3) is bonded to the polymer main chain directly or via a spacer at any site, or a part or all of the UV-absorbing group is a polymer main chain. It forms part of the chain. Examples of the spacer include those listed as the spacer in the general formula (1).

In the general formula (4), R ₂₆ and R ₂₇ each represents an alkyl group having 1 to 10 carbon atoms, R ₂₈ , R ₂₉ and R ₃₀ each represents an alkyl group, an alkoxy group, an alkylthio group, and an amino group, and X , Y each represents an electron-withdrawing group. Examples of the electron-withdrawing group include those exemplified as examples of EWG _{1 to} EWG ₄ in the general formulas (17) and (18). However, R _{26 to} R ₃₀ and X and Y may have a halogen atom and a substituent, and examples of the substituent are listed as examples of the substituent that Sp ₁ can take in the general formula (1). And the like. R _{26 to} R ₃₀ may be the same or different from each other. The alkyl group, alkoxy group, alkylthio group, and amino group may have a substituent or may be unsubstituted.

However, R _{26 to} R ₃₀ , X, and Y may be connected to each other to form a 5- or 6-membered ring. However, the ultraviolet absorbing group represented by the general formula (4) is bonded to the polymer main chain directly or via a spacer at any site, or a part or all of the ultraviolet absorbing group is overlapped. It forms part of the combined main chain. Examples of the UV-absorbing group include the same groups as those listed as the UV-absorbing group in the general formula (1). Similarly, examples of the spacer include those listed as the spacer in the general formula (1).

In the general formula (5), R _{66 to} R ₇₁ each represent a hydrogen atom, a halogen atom, or a substituent. Preferably, R _{66 to} R ₇₀ are a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an amino group, an alkyl group. An amino group is mentioned, and _R71 is a hydrogen atom, a halogen atom, or an alkyl group. However, R _{66 to} R ₇₀ may be connected to each other to form a 5- or 6-membered ring. X and Y are synonymous with X and Y in the general formula (4). In R _{66 to} R ₇₀ , adjacent ones may be bonded to each other to form a ring. In the ultraviolet absorbing group represented by the general formula (5), X and Y are not bonded to each other to form a ring. However, the ultraviolet absorbing group represented by the general formula (5) is bonded to the polymer main chain directly or via a spacer at any site, or a part or all of the ultraviolet absorbing group is overlapped. It forms part of the combined main chain. Examples of the UV-absorbing group include the same groups as those listed as the UV-absorbing group in the general formula (1). Similarly, examples of the spacer include those listed as the spacer in the general formula (1).

  The UV-absorbing polymer having either the repeating unit represented by the general formula (6) or the repeating unit represented by the general formula (7) is a copolymer with an ethylenically unsaturated monomer. preferable.

In the general formulas (6) and (7), R _{31 to} R ₃₄ each represent a halogen atom or a substituent. Examples of the substituent are listed as examples of the substituent of Sp _{1 in} the general formula (1). And the like. l represents 0, 1, 2, 3, m represents 0, 1, 2, 3, 4, s represents 0, 1, 2, 3, 4, o represents 0, 1, 2, 3, J ₄ represents * —O—, * —NR ₁ —, * —S—, * —SO—, * —SO ₂ —, * —POO—, * —CO—, * —COO—, * —NR _{2. CO -, * - NR 3 COO} -, * - NR 4 CONR 5 -, * - OCO -, * - OCONR 6 -, * - CONR 7 -, * - NR 8 SO -, * - NR 9 SO 2 -, * -SONR ₁₀ -and * -SO ₂ NR ₁₁ -are represented (note that * indicates that the group is connected to an ultraviolet absorbing group by *), preferably * -O-, * -NR _1-. , * - S -, * - SO -, * - SO 2 -, * - NR 3 COO -, * - NR 4 CONR 5 - a. J ₅ is * -O-, * -NR _1- , * -S-, * -SO-, * -SO _2- , * -POO-, * -CO-, * -COO-, * -NR _{2. CO -, * - NR 3 COO} -, * - NR 4 CONR 5 -, * - OCO -, * - OCONR 6 -, * - CONR 7 -, * - NR 8 SO -, * - NR 9 SO 2 -, * -SONR ₁₀ -and * -SO ₂ NR ₁₁ -are represented (note that the * mark indicates that it is connected to an ultraviolet absorbing group (on the side opposite to Sp ₄ ) with *), preferably *- O—, * —NR ₁ —, * —S—, * —SO—, * —SO ₂ —, * —NR ₃ COO—, * —NR ₄ CONR ₅ —. R ₁ to R ₁₁ has the same meaning as R ₁ to R ₁₁ in the general formula (1). Sp ₄ and Sp ₅ represent a divalent linking group and may have a halogen atom or a substituent. Specific examples of the linking group and the substituent are based on Sp ₁ in the general formula (1). When l is 2 or 3, R ₃₁ may be the same or different from each other. When m is any one of 2, 3, and 4, R ₃₂ may be the same as or different from each other. When o is 2 or 3, R ₃₄ may be the same as or different from each other. When s is any of 2, 3, and 4, R ₃₃ may be the same as or different from each other.

  In the general formulas (6) and (7), it is preferable that s and o or l and m are not 0.

In the general formulas (8) and (9), R ₃₅ and R ₃₆ each represent a halogen atom and a substituent. Examples of the substituent include those Sp ₁ in the general formula (1) is exemplified as substituents which may be taken. R ₃₅ and R ₃₆ may be the same or different from each other. q represents 0, 1, 2, 3, 4; r represents 0, 1, 2, 3; When r is 2 or 3, R ₃₆ may be the same as or different from each other. When q is 2, 3, or 4, R ₃₅ may be the same as or different from each other. R _{37 to} R ₃₉ each represent a hydrogen atom, a halogen atom, or a substituent. Sp ₆ represents a divalent linking group and may have a halogen atom or a substituent. In Sp ₆ , specific examples of the linking group and the substituent are based on Sp ₁ of the general formula (1).

  The ultraviolet absorbing polymer according to the present invention includes a polymer containing a repeating unit represented by the general formulas (1), (2), (6), and (7), and the general formulas (3) and (4). A polymer containing a repeating unit having an ultraviolet-absorbing group represented by (5), or a copolymer derived from a compound represented by formulas (8) and (9). As long as it contains a repeating unit or a copolymer derived from a compound, it may be a homopolymer or a copolymer with a plurality of other continuous units.

  Other continuous units include, for example, acrylamide derivative-containing monomers, acrylic ester derivative-containing monomers, methacrylic ester derivative-containing monomers, vinyl ether derivative-containing monomers, ethylene oxide derivative-containing monomers, vinyl ester derivative-containing monomers, dicarboxylic acid derivative-containing monomers, Examples thereof include continuous units obtained from diol derivative-containing monomers and diamine derivative-containing monomers.

  When the ultraviolet absorbing polymer according to the present invention is used as a copolymer, it is preferably a copolymer with an ethylenically unsaturated monomer. More preferably, the ethylenically unsaturated monomer is a methacrylic acid ester having a hydroxyl group or an ether bond, or an acrylic acid ester having a hydroxyl group.

  Preferred examples are given below. Methacrylic acid and its ester derivatives (methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, octyl methacrylate, cyclohexyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, tetrahydrofurfuryl methacrylate, benzyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, etc.) or acrylic acid and its ester derivatives (methyl acrylate, ethyl acrylate, propyl acrylate, Butyl acrylate, i-butyl acrylate, t-butyl acrylate, octyl acrylate, cyclohexyl acrylate, 2-hydroxyethyl acrylate, 2-acrylate Droxypropyl, tetrahydrofurfuryl acrylate, benzyl acrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, etc.), alkyl vinyl ether (methyl vinyl ether, ethyl vinyl ether, butyl vinyl ether, etc.), alkyl vinyl ester (vinyl formate, vinyl acetate) , Vinyl butyrate, vinyl caproate, vinyl stearate, etc.), acrylonitrile, vinyl chloride, styrene and the like can be mentioned as preferred examples.

  Among these ethylenically unsaturated monomers, acrylic acid ester having a hydroxyl group or ether bond, or methacrylic acid ester (for example, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, tetrahydrofurfuryl acrylate, acrylic acid) 2-Ethoxyethyl, diethylene glycol ethoxylate acrylate, 3-methoxybutyl acrylate) are preferred. These may be used alone or in combination of two or more, and copolymerized with the ultraviolet absorbing monomer.

  Moreover, it is preferable that content of an ultraviolet absorptive monomer in an ultraviolet absorptive polymer is 1-70 mass% or more. More preferably, it is 20-70 mass%, Furthermore, it is preferable that it is 30-60 mass%. In particular, when the ultraviolet absorbing polymer is a copolymer of a repeating unit represented by the general formula (6) and an ethylenically unsaturated monomer, it is represented by the general formula (6) in the ultraviolet absorbing polymer. The content of the repeating unit is preferably 1 to 45% by mass, more preferably 10 to 45% by mass, and still more preferably 20 to 40% by mass. In particular, it is preferable that the content of the repeating unit represented by the general formula (7) in the ultraviolet absorbing polymer is 1 to 55% by mass. More preferably, it is 10-55 mass%, More preferably, it is 20-50 mass%.

  The polymer used in the present invention is preferably mixed in a proportion of 0.01 to 40% by mass, more preferably in a proportion of 0.01 to 30% by mass, with respect to the composition comprising an acrylic resin and a cellulose ester resin. It is preferable to mix with. In addition, when the film thickness of an optical film is 65 micrometers or less, 1-10 mass% is preferable. Moreover, when the film thickness of an optical film is 70 micrometers or more, 0.5-5 mass% is preferable, More preferably, it is 0.5-2.5 mass%. If the haze at the time of forming the optical film at this time is 0 to 0.5, the haze is not particularly limited, but the haze is preferably 0.2 or less. More preferably, the haze when the optical film is formed is 0 to 0.2, and the transmittance at 380 nm is 0 to 10%.

  Further, the ultraviolet absorbing polymer of the present invention can be used together with other low molecular compounds, high molecular compounds, inorganic compounds, or the like when mixed with a composition comprising an acrylic resin and a cellulose ester resin. For example, it is also a kind of preferable aspect to mix the ultraviolet-absorbing polymer of the present invention and another low-molecular-weight ultraviolet absorber into the composition at the same time.

  The UV-absorbing polymer can be used without particular limitation as long as it is not a monomer, but the weight average molecular weight of the preferred polymer is 500 to 1,000,000, particularly preferably 1,000 to 100,000. More preferably, it is 2000-20000, Furthermore, it is 7000-15000.

  The polymerization method of the polymer of the present invention is not particularly limited, and examples thereof include radical polymerization, anionic polymerization, and cationic polymerization. Examples of the initiator for the radical polymerization method include azo compounds and peroxides, and examples thereof include azobisisobutyronitrile (AIBN), azobisisobutyric acid diester derivatives, and benzoyl peroxide.

  The polymerization solvent is not particularly limited. For example, aromatic hydrocarbon solvents such as toluene and chlorobenzene, halogenated hydrocarbon solvents such as dichloroethane and chloroform, ether solvents such as tetrahydrofuran and dioxane, and amide solvents such as dimethylformamide. And alcohol solvents such as methanol, ester solvents such as ethyl acetate, ketone solvents such as acetone, water solvents and the like. Depending on the selection of the solvent, solution polymerization that polymerizes in a homogeneous system, precipitation polymerization that precipitates the produced polymer, and emulsion polymerization that polymerizes in a micelle state can also be performed.

  Since the UV-absorbing polymer of the present invention has good compatibility with acrylic resins and cellulose ester resins and has a high molecular weight as compared with conventionally known low-molecular UV absorbers, etc., the production of optical films No bleeding phenomenon or crystal precipitation, which has been a problem during saponification in the process and with the alkali treatment solution, does not occur. Furthermore, the generation of haze is extremely small, the polymer itself is sufficiently stable against ultraviolet rays, heat and humidity, and there is almost no deterioration in ultraviolet absorption properties even when exposed to high temperatures and high humidity, and resistance to moisture and heat. An excellent optical film can be obtained.

<< Compounds Represented by General Formulas (UVA1) to (UVA3) >>
In the present invention, it is also a preferable aspect to use at least one compound selected from the compounds represented by the general formulas (UVA1) to (UVA3) as the ultraviolet absorber. In addition, it is preferable that the compounds represented by the general formulas (UVA1) to (UVA3) are compounds represented by the following general formulas (UVA4) to (UVA6), respectively.

(In the general formulas (UVA4) to (UVA6), R ₁ and R ₂ represent substituents, and X represents —COO—, —OCO—, —NR ₁₁ CO—, —CONR ₁₁ —, —O—, —NR) ₁₂ R ₁₃ —, —SO ₂ NR ₁₄ —, —NR ₁₄ SO ₂ —, —S—, —SO ₂ —, wherein L ₁ is a divalent linking group, L ₂ is a trivalent linking group, L ₃ Represents a tetravalent linking group, R ₁₁ , R ₁₂ , R ₁₃ and R ₁₄ represent a hydrogen atom, an alkyl group or an aryl group, p represents an integer of 0 to 3, and q represents an integer of 0 to 4. )
In the general formulas (UVA1) to (UVA6), R ₁ and R ₂ represent a substituent, and examples of the substituent include a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), an alkyl group (for example, Methyl group, ethyl group, isopropyl group, hydroxyethyl group, methoxymethyl group, trifluoromethyl group, t-butyl group, etc.), alkenyl group (for example, vinyl group, allyl group, 3-buten-1-yl group, etc.) An aryl group (for example, phenyl group, naphthyl group, p-tolyl group, p-chlorophenyl group, etc.), an alkoxy group (for example, methoxy group, ethoxy group, isopropoxy group, n-butoxy group, etc.), aryloxy group ( For example, phenoxy group etc.), acyloxy group (eg acetoxy group, pivaloyloxy group, benzoyloxy group etc.), acyl group (eg Acetyl group, propanoyl group, butyroyl group, etc.), alkoxycarbonyl group (eg, methoxycarbonyl group, ethoxycarbonyl group, etc.), aryloxycarbonyl group (eg, phenoxycarbonyl group, etc.), carbamoyl group (eg, methylcarbamoyl group, ethyl) Carbamoyl group, dimethylcarbamoyl group, etc.), amino group, alkylamino group (eg, methylamino group, ethylamino group, diethylamino group, etc.), anilino group (eg, anilino group, N-methylanilino group, etc.), acylamino group (eg, Acetylamino group, propionylamino group, etc.), hydroxyl group, cyano group, nitro group, sulfonamide group (eg methanesulfonamide group, benzenesulfonamide group etc.), sulfamoylamino group (eg dimethylsulfa group) Moylamino group etc.), sulfonyl group (eg methanesulfonyl group, butanesulfonyl group, phenylsulfonyl group etc.), sulfamoyl group (eg ethylsulfamoyl group, dimethylsulfamoyl group etc.), sulfonylamino group (eg methane Sulfonylamino group, benzenesulfonylamino group, etc.), ureido group (eg, 3-methylureido group, 3,3-dimethylureido group, 1,3-dimethylureido group, etc.), imide group (eg, phthalimide group, etc.), Silyl groups (for example, trimethylsilyl group, triethylsilyl group, t-butyldimethylsilyl group, etc.), alkylthio groups (for example, methylthio group, ethylthio group, n-butylthio group, etc.), arylthio groups (for example, phenylthio group, etc.), etc. Preferably, an alkyl group, ant A Le group.

L ₁ represents a divalent linking group, for example, an alkylene group (for example, methylene, ethylene, 2,2-dimethylpropylene, propylene, 1,4-cyclohexylene, dodecylene, hexadecylene, 2-ethylhexylene, 2-hexyl). decalene, etc.), an arylene group (e.g., phenylene, naphthylene), - O -, - S -, - NR 21 R 22 , or combinations thereof and the like. R ₂₁ and R ₂₂ represent a hydrogen atom, an alkyl group or an aryl group.

L ₂ represents a trivalent linking group, and examples thereof include the following structures. In the formula, * is a point connected to X.

In the formula, L ₃ represents a tetravalent linking group, and examples thereof include the following structures. In the formula, * is a point connected to X.

Of L ₁ , L ₂ and L ₃ , L ₁ , that is, the general formula (UVA1), particularly the general formula (UVA4) is preferable in the present invention. For L ₁ , L ₂ and L ₃ as the linking group, a linking group containing an ether bond is particularly preferred.

  Hereinafter, although the compound represented by general formula (UVA1)-(UVA6) is illustrated, it is not limited to these.

(Synthesis example)
Hereinafter, although the synthesis method of the compound concerning this invention is demonstrated concretely, this invention is not limited by these.

Synthesis example 1
<Synthesis of Exemplified Compound 2>
2 g of Compound A was suspended in 10 ml of toluene, 0.1 ml of DMF and 1.14 g of thionyl chloride were added, and the mixture was heated to 60 ° C. and stirred for 30 minutes. As the reaction progressed, it began to dissolve and became a homogeneous solution after the reaction was completed. The solvent of the reaction mixture was removed under reduced pressure.

  80 ml of acetonitrile was added to the residue and suspended. In a separate container, 0.34 g of diethylene glycol and 0.76 g of pyridine were dissolved in acetonitrile, heated to 75 ° C. and stirred.

  The previous acetonitrile suspension was quickly added to it and stirred for 2 hours while maintaining 75 ° C. After completion of the reaction, the reaction mixture was cooled and then acetonitrile was removed under reduced pressure, followed by extraction with ethyl acetate and water.

  The organic layer was removed under reduced pressure, the residue was purified by silica gel column chromatography, and recrystallized from ethyl acetate to obtain 0.4 g (yield 18%) of Exemplary Compound 2. The structure was confirmed by NMR and Mass spectrum.

  1H-NMR (d-DMSO): σ 1.28 (s, 18H); 3.92 (m, 4H); 4.51 (m, 4H); 7.09 (d, J = 8.8 Hz, 2H) 7.49 (dd, J = 2.4 Hz, 8.5 Hz, 2H); 7.71 (d, J = 2.4 Hz, 2H); 7.93 (d, J = 8.8 Hz, 2H); 7.9 (d, J = 8.8 Hz, 2H); 8.60 (s, 2H); 10.2 (s, 2H)

Synthesis example 2
<Synthesis of Exemplary Compound 3>
2 g of Compound A was suspended in 10 ml of toluene, 0.1 ml of DMF and 1.14 g of thionyl chloride were added, and the mixture was heated to 60 ° C. and stirred for 30 minutes. As the reaction progressed, it began to dissolve and became a homogeneous solution after the reaction was completed. The solvent of the reaction mixture was removed under reduced pressure.

  80 ml of acetonitrile was added to the residue and suspended. In a separate container, 0.32 g of 2,2-dimethylpropanediol and 0.76 g of pyridine were dissolved with acetonitrile, and the mixture was heated to 75 ° C. and stirred.

  The previous acetonitrile suspension was quickly added to it and stirred for 2 hours while maintaining 75 ° C. After completion of the reaction, the reaction mixture was cooled and then acetonitrile was removed under reduced pressure, followed by extraction with ethyl acetate and water.

  The organic layer was removed under reduced pressure, the residue was purified by silica gel column chromatography, and recrystallized from ethyl acetate to obtain 0.4 g (yield 18%) of Exemplary Compound 3. The structure was confirmed by NMR and Mass spectrum.

  1H-NMR (d-DMSO): σ 0.97 (s, 6H); 1.31 (s, 18H); 4.34 (s, 4H); 7.12 (d, d = 8.8 Hz, 2H) 7.51 (dd, J = 2.4 Hz, 8.8 Hz, 2H); 7.74 (d, J = 2.4 Hz, 2H); 8.04 (dd, J = 1.4 Hz, 9.0 Hz); , 2H); 8.18 (d, J = 9.0 Hz, 4H); 8.71 (s, 2H); 10.3 (s, 2H)

  Other exemplified compounds can be synthesized in the same manner.

  When the compounds represented by the general formulas (UVA1) to (UVA6) are mixed with other transparent polymers, a low molecular compound, a high molecular compound, an inorganic compound, or the like can be used together as necessary.

  For example, it is also one of the preferable embodiments that the compound represented by the general formulas (UVA1) to (UVA6) (ultraviolet absorber) and another ultraviolet absorber or ultraviolet absorbent polymer are simultaneously mixed with another transparent polymer. is there. Similarly, it is also one of the preferable embodiments that additives such as an antioxidant, a plasticizer, and a flame retardant are mixed at the same time.

  The method for adding the ultraviolet absorbent according to the present invention to the optical film may be contained in the optical film or may be applied onto the optical film. When contained in an optical film, it may be added directly.

  The amount of the compound represented by the general formulas (UVA1) to (UVA6) is not uniform depending on the type of compound, use conditions, etc., but when used as an ultraviolet absorber, it consists of an acrylic resin and a cellulose ester resin. It is preferable to mix at a ratio of 0.01 to 40% by mass with respect to the composition, and it is more preferable to mix at a ratio of 0.01 to 30% by mass. In addition, when the film thickness of an optical film is 65 micrometers or less, 1-5 mass% is preferable. Moreover, when the film thickness of an optical film is 70 micrometers or more, 0.5-2.5 mass% is preferable.

  Furthermore, from the viewpoint of preventing liquid crystal deterioration, those having excellent ultraviolet absorption performance at a wavelength of 380 nm or less and less visible light absorption of 400 nm or more are preferable from the viewpoint of good liquid crystal display properties. If the haze at the time of forming the optical film at this time is 0 to 0.5, the haze is not particularly limited, but the haze is preferably 0.2 or less. More preferably, the haze when the optical film is formed is 0 to 0.2, and the transmittance at 380 nm is 0 to 10%.

《Other UV absorbers》
Moreover, in this invention, a conventionally well-known ultraviolet absorber can also be used individually or in combination.

  Although it does not specifically limit as a conventionally well-known ultraviolet absorber, For example, a salicylic acid type ultraviolet absorber (phenyl salicylate, p-tert-butyl salicylate, etc.) or a benzophenone type ultraviolet absorber (2,4-dihydroxybenzophenone, 2, 2) '-Dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, etc.), benzotriazole UV absorption Agents (2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) ) -5-chlorobenzotriazole, 2- (2 -Hydroxy-3 ', 5'-di-tert-amyl-phenyl) benzotriazole, 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2- (3,5-di-t-butyl-2-hydroxyphenyl) benzotriazole, etc.), cyanoacrylate ultraviolet absorber (2′-ethylhexyl-2- Cyano-3,3-diphenyl acrylate, ethyl-2-cyano-3- (3 ', 4'-methylenedioxyphenyl) -acrylate, etc.), triazine ultraviolet absorbers, or JP-A-58-185777, the same Examples thereof include compounds described in 59-149350, nickel complex compounds, inorganic powders, and the like.

  Here, among ultraviolet absorbers, ultraviolet absorbers having a molecular weight of 400 or more are less likely to volatilize at a high boiling point and are difficult to disperse even during high-temperature molding, so that the weather resistance is effectively improved with a relatively small amount of addition. be able to. In addition, since the transition from the thin coating layer to the substrate layer is particularly small and hardly precipitates on the surface of the laminate, the amount of contained UV absorber is maintained for a long time, and the durability of the weather resistance improvement effect is excellent. From the point of view, it is preferable.

  Examples of the ultraviolet absorber having a molecular weight of 400 or more include 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2-benzotriazole, 2,2-methylenebis [4- (1, 1,3,3-tetrabutyl) -6- (2H-benzotriazol-2-yl) phenol], bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis ( Hindered amines such as 1,2,2,6,6-pentamethyl-4-piperidyl) sebacate and 2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butylmalonic acid Bis (1,2,2,6,6-pentamethyl-4-piperidyl), 1- [2- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy] ethyl L] -4- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy] -2,2,6,6-tetramethylpiperidine and the like, hindered phenol and hindered amine A hybrid system having both structures can be mentioned, and these can be used alone or in combination of two or more. Among these, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2-benzotriazole and 2,2-methylenebis [4- (1,1,3,3- Tetrabutyl) -6- (2H-benzotriazol-2-yl) phenol] is particularly preferred.

  Conventionally known ultraviolet absorbers used together with the ultraviolet absorber according to the present invention include benzotriazole ultraviolet absorbers and benzophenone ultraviolet absorbers that are highly transparent and excellent in preventing deterioration of polarizing plates and liquid crystal elements. A benzotriazole-based ultraviolet absorber with less unnecessary coloring is particularly preferable.

  In the present invention, a conventionally known ultraviolet absorbing polymer can also be used. Although it does not specifically limit as a conventionally well-known ultraviolet absorptive polymer, For example, the polymer which homopolymerized RUVA-93 (made by Otsuka Chemical), the polymer which copolymerized RUVA-93, and another monomer, etc. are mentioned. .

  Specific examples include PUVA-30M obtained by copolymerization of RUVA-93 and methyl methacrylate at a ratio (mass ratio) of 3: 7, and PUVA-50M obtained by copolymerization at a ratio of 5: 5 (mass ratio). It is done.

<Acrylic particles>
In the present invention, the optical film may contain acrylic particles.

  The acrylic particles according to the present invention are characterized by being present in the state of particles in the acrylic resin and cellulose ester resin and the optical film (also referred to as incompatible state).

  The acrylic particles may be obtained by, for example, collecting a predetermined amount of the produced optical film, dissolving it in a solvent, stirring, and sufficiently dissolving and dispersing the PTFE membrane filter having a pore diameter less than the average particle diameter of the acrylic particles. It is preferable that the weight of the insoluble matter filtered and collected is 90% by mass or more of the acrylic particles added to the optical film.

  The acrylic particles used in the present invention are not particularly limited, but are preferably acrylic particles having a layer structure of two or more layers, and particularly preferably the following multilayer structure acrylic granular composite.

  The multilayer structure acrylic granular composite is formed by laminating an innermost hard layer polymer, a cross-linked soft layer polymer exhibiting rubber elasticity, and an outermost hard layer polymer from the center to the outer periphery. This refers to a particulate acrylic polymer having a structure.

  Preferred embodiments of the multilayer structure acrylic granular composite used in the acrylic resin composition of the present invention include the following. (A) Monomer composed of 80 to 98.9% by mass of methyl methacrylate, 1 to 20% by mass of alkyl acrylate having 1 to 8 carbon atoms in the alkyl group, and 0.01 to 0.3% by mass of polyfunctional grafting agent An innermost hard layer polymer obtained by polymerizing the body mixture, (b) in the presence of the innermost hard layer polymer, 75 to 98.5% by mass of an alkyl acrylate having an alkyl group with 4 to 8 carbon atoms, A crosslinked soft layer polymer obtained by polymerizing a monomer mixture comprising a multifunctional crosslinking agent of 0.01 to 5% by mass and a multifunctional grafting agent of 0.5 to 5% by mass; (c) the innermost hard In the presence of a polymer comprising a layer and a crosslinked soft layer, a monomer mixture comprising 80 to 99% by mass of methyl methacrylate and 1 to 20% by mass of alkyl acrylate having 1 to 8 carbon atoms in the alkyl group is polymerized. Outermost hard layer weight And the obtained three-layer structure polymer is an innermost hard layer polymer (a) 5 to 40% by mass, a soft layer polymer (b) 30 to 60% by mass, and The outermost hard layer polymer (c) is composed of 20 to 50% by mass, has an insoluble part when fractionated with acetone, and an acrylic granular composite having a methyl ethyl ketone swelling degree of 1.5 to 4.0 at the insoluble part. .

  As disclosed in Japanese Patent Publication No. 60-17406 or Japanese Patent Publication No. 3-39095, not only the composition and particle size of each layer of the multilayer structure acrylic granular composite are defined, but also the multilayer structure acrylic granular composite. By setting the tensile modulus of the body and the degree of swelling of methyl ethyl ketone in the acetone-insoluble part within a specific range, it is possible to realize a further sufficient balance between impact resistance and stress whitening resistance.

  Here, the innermost hard layer polymer (a) constituting the multi-layer structure acrylic granular composite is 80 to 98.9% by mass of methyl methacrylate and 1 to 20% of alkyl acrylate having 1 to 8 carbon atoms in the alkyl group. % And a polyfunctional grafting agent obtained by polymerizing a monomer mixture consisting of 0.01 to 0.3% by mass.

  Here, examples of the alkyl acrylate having 1 to 8 carbon atoms in the alkyl group include methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, s-butyl acrylate, 2-ethylhexyl acrylate, and the like. And n-butyl acrylate are preferably used.

  The proportion of the alkyl acrylate unit in the innermost hard layer polymer (a) is 1 to 20% by mass. When the unit is less than 1% by mass, the thermal decomposability of the polymer is increased, while the unit is 20% by mass. If it exceeds 50%, the glass transition temperature of the innermost hard layer polymer (c) is lowered, and the impact resistance imparting effect of the three-layer structure acrylic granular composite is lowered.

  Examples of the polyfunctional grafting agent include polyfunctional monomers having different polymerizable functional groups, such as allyl esters of acrylic acid, methacrylic acid, maleic acid, and fumaric acid, and allyl methacrylate is preferably used. . The polyfunctional grafting agent is used to chemically bond the innermost hard layer polymer and the soft layer polymer, and the ratio used during the innermost hard layer polymerization is 0.01 to 0.3% by mass. .

  The crosslinked soft layer polymer (b) constituting the acrylic granular composite is an alkyl acrylate 75-98.5 having 1 to 8 carbon atoms in the presence of the innermost hard layer polymer (a). What is obtained by polymerizing a monomer mixture consisting of mass%, polyfunctional crosslinking agent 0.01 to 5 mass% and polyfunctional grafting agent 0.5 to 5 mass% is preferable.

  Here, as the alkyl acrylate having 4 to 8 carbon atoms in the alkyl group, n-butyl acrylate or 2-ethylhexyl acrylate is preferably used.

  In addition to these polymerizable monomers, it is possible to copolymerize 25% by mass or less of other monofunctional monomers capable of copolymerization.

  Other monofunctional monomers that can be copolymerized include styrene and substituted styrene derivatives. As the ratio of the alkyl acrylate having 4 to 8 carbon atoms in the alkyl group and styrene increases, the glass transition temperature of the produced polymer (b) decreases as the former increases, that is, it can be softened.

  On the other hand, from the viewpoint of the transparency of the resin assembly, the refractive index of the soft layer polymer (b) at room temperature is set to the innermost hard layer polymer (a), the outermost hard layer polymer (c), and the hard heat. It is more advantageous to make it closer to the plastic acrylic resin, and the ratio between them is selected in consideration of these.

  For example, in applications where the coating layer thickness is small, it is not always necessary to copolymerize styrene.

  As the polyfunctional grafting agent, those mentioned in the item of the innermost layer hard polymer (a) can be used. The polyfunctional grafting agent used here is used to chemically bond the soft layer polymer (b) and the outermost hard layer polymer (c), and the proportion used during the innermost hard layer polymerization is impact resistance. 0.5-5 mass% is preferable from a viewpoint of the property provision effect.

  As the polyfunctional crosslinking agent, generally known crosslinking agents such as divinyl compounds, diallyl compounds, diacrylic compounds, and dimethacrylic compounds can be used, and polyethylene glycol diacrylate (molecular weight 200 to 600) is preferably used.

  The polyfunctional cross-linking agent used here is used to generate a cross-linked structure at the time of polymerization of the soft layer (b) and develop an effect of imparting impact resistance. However, if the above-mentioned polyfunctional grafting agent is used during the polymerization of the soft layer, the polyfunctional crosslinking agent is not an essential component because the crosslinked structure of the soft layer (b) is generated to some extent. Is preferably 0.01 to 5% by mass from the viewpoint of imparting impact resistance.

  In the presence of the innermost hard layer polymer (a) and the soft layer polymer (b), the outermost hard layer polymer (c) constituting the multilayer structure acrylic granular composite is 80 to 99 masses of methyl methacrylate. % And a monomer mixture obtained by polymerizing a monomer mixture consisting of 1 to 20% by mass of an alkyl acrylate having 1 to 8 carbon atoms in the alkyl group is preferable.

  Here, as the acrylic alkylate, those described above are used, and methyl acrylate and ethyl acrylate are preferably used. The ratio of the alkyl acrylate unit in the outermost hard layer (c) is preferably 1 to 20% by mass.

  Further, for the purpose of improving the compatibility with the acrylic resin during the polymerization of the outermost hard layer (c), an alkyl mercaptan or the like can be used as a chain transfer agent to adjust the molecular weight.

  In particular, it is preferable to provide the outermost hard layer with a gradient such that the molecular weight gradually decreases from the inside toward the outside in order to improve the balance between elongation and impact resistance. As a specific method, the monomer mixture for forming the outermost hard layer is divided into two or more, and the molecular weight is increased from the inside by a method of sequentially increasing the amount of chain transfer agent added each time. It is possible to make it smaller toward the outside.

  The molecular weight formed at this time can also be examined by polymerizing the monomer mixture used each time under the same conditions and measuring the molecular weight of the obtained polymer.

  The particle diameter of the acrylic granular composite which is a multilayer structure polymer preferably used in the present invention is not particularly limited, but is preferably 10 nm or more and 1000 nm or less, and more preferably 20 nm or more and 500 nm or less. More preferably, it is most preferably 50 nm or more and 400 nm or less.

  In the acrylic granular composite that is a multilayer structure polymer preferably used in the present invention, the mass ratio of the core and the shell is not particularly limited, but when the entire multilayer structure polymer is 100 parts by mass, The core layer is preferably 50 parts by mass or more and 90 parts by mass or less, and more preferably 60 parts by mass or more and 80 parts by mass or less.

  Examples of such commercially available multilayered acrylic granular composites include, for example, “Metablene” manufactured by Mitsubishi Rayon Co., “Kane Ace” manufactured by Kaneka Chemical Co., Ltd., “Paralloid” manufactured by Kureha Chemical Co., Ltd., Rohm and Haas “Acryloid” manufactured by KK, “Staffyroid” manufactured by Ganz Kasei Kogyo Co., Ltd., “Parapet SA” manufactured by Kuraray Co., Ltd., and the like can be used alone or in combination.

  In addition, specific examples of the acrylic particles that are graft copolymers that are preferably used as the acrylic particles preferably used in the present invention include unsaturated carboxylic acid ester monomers, unsaturated monomers in the presence of a rubbery polymer. A graft copolymer obtained by copolymerizing a monomer mixture comprising a saturated carboxylic acid monomer, an aromatic vinyl monomer, and, if necessary, other vinyl monomers copolymerizable therewith. Can be mentioned.

  There is no particular limitation on the rubbery polymer used for the acrylic particles as the graft copolymer, but diene rubber, acrylic rubber, ethylene rubber, and the like can be used. Specific examples include polybutadiene, styrene-butadiene copolymer, block copolymer of styrene-butadiene, acrylonitrile-butadiene copolymer, butyl acrylate-butadiene copolymer, polyisoprene, butadiene-methyl methacrylate copolymer. , Butyl acrylate-methyl methacrylate copolymer, butadiene-ethyl acrylate copolymer, ethylene-propylene copolymer, ethylene-propylene-diene copolymer, ethylene-isoprene copolymer, and ethylene-acrylic acid Examples thereof include a methyl copolymer. These rubbery polymers can be used alone or in a mixture of two or more.

  Moreover, since the transparency of the optical film of this invention can be obtained when each refractive index of an acrylic resin and an acrylic particle is approximated, it is preferable. Specifically, the refractive index difference between the acrylic particles and the acrylic resin is preferably 0.05 or less, more preferably 0.02 or less, and particularly preferably 0.01 or less.

  In order to satisfy such a refractive index condition, a method of adjusting the monomer unit composition ratio of the acrylic resin and / or a composition ratio of the rubbery polymer or monomer used in the acrylic particles is prepared. Depending on the method, the refractive index difference can be reduced, and an optical film excellent in transparency can be obtained.

  The difference in refractive index referred to here means that the optical film of the present invention is sufficiently dissolved under a suitable condition in a solvent in which an acrylic resin is soluble to form a cloudy solution, which is then dissolved in a solvent by an operation such as centrifugation. After separating into a part and an insoluble part and purifying the soluble part (acrylic resin) and the insoluble part (acrylic particles), the difference in the measured refractive index (23 ° C., measurement wavelength: 550 nm) is shown.

  In the present invention, the method of blending the acrylic particles with the acrylic resin is not particularly limited, and after blending the acrylic resin and other optional components in advance, usually at 200 to 350 ° C. while adding the acrylic particles, uniaxial or biaxial A method of uniformly melt-kneading with a shaft extruder is preferably used.

  In addition, a method in which a solution in which acrylic particles are dispersed in advance is added to and mixed with a solution (dope solution) in which an acrylic resin and a cellulose ester resin are dissolved, and a solution in which acrylic particles and other optional additives are dissolved and mixed. A method such as in-line addition can be used.

  A commercially available thing can also be used as an acrylic particle of this invention. For example, metabrene W-341 (C2) (manufactured by Mitsubishi Rayon Co., Ltd.), Chemisnow MR-2G (C3), MS-300X (C4) (manufactured by Soken Chemical Co., Ltd.) and the like can be mentioned.

  The optical film of the present invention preferably contains 0.5 to 45% by mass of acrylic particles with respect to the total mass of the resin constituting the film.

(Phase difference control agent)
In the present application, as the retardation control agent, compounds described in JP-A No. 2002-296421 and various ester plasticizers can be used. Hereinafter, preferred ester compounds will be described in detail.

  In the present invention, among various compounds described below, a compound having a structure in which aromatic rings are arranged in a plane when added and stretched as an additive is preferable. For this reason, a compound in which an aromatic ring is contained as a block in the main chain or at the terminal is preferable.

<Polyester polyol of glycol and dibasic acid>
The polyester polyol that can be used in the present invention includes a dehydration condensation reaction between a glycol having an average carbon number of 2 to 3.5 and a dibasic acid having an average carbon number of 4 to 5.5, or the glycol. It is preferable to be produced by a conventional method by addition of a dibasic anhydride having an average carbon number of 4 to 5.5 and a dehydration condensation reaction.

《Glycol》
Examples of the glycol used in the polyester polyol include ethylene glycol, diethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 2-methyl-1,3-propanediol, 1,4-butylene glycol, and neopentyl. Glycol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, and the like. These may be used alone or in combination of two or more. For example, ethylene glycol or a mixture of ethylene glycol and diethylene glycol Is particularly preferably used.

  Regarding the above-mentioned glycol, it is preferable that the average number of carbon atoms of the glycol is in the range of 2 to 3.5 from the viewpoint of production of polyester polyol, compatibility with cellulose, transparency and the like.

  When a mixture of ethylene glycol and diethylene glycol is used as the glycol, the molar ratio of ethylene glycol / diethylene glycol is preferably 25 to 100/75 to 0, and for cellulose esters having excellent compatibility with cellulose esters. A modifier can be obtained. Furthermore, it is more preferably 25-40 / 75-60, and 60-95 / 40-5, and by adjusting to such a range, the crystallinity and melting point of the polyester polyol are close to those of conventional ones. Productivity is also improved.

《Dibasic acid》
Next, examples of the dibasic acid constituting the polyester polyol used in the present invention include succinic acid, glutaric acid, adipic acid, and sebacic acid. These can be used alone or in combination of two or more. For example, succinic acid or a mixture of succinic acid and terephthalic acid is particularly preferably used.

  Moreover, regarding the above-mentioned dibasic acid, it is preferable that the average number of carbon atoms of the dibasic acid is in the range of 4 to 5.5 from the viewpoint of production of polyester polyol, compatibility with cellulose, transparency, and the like. .

  When a mixture of succinic acid and terephthalic acid is used as the dibasic acid, the molar ratio of succinic acid / terephthalic acid is preferably 25-100 / 75-0 and has excellent compatibility with the cellulose ester. A cellulose ester modifier can be obtained. Furthermore, it is more preferably 25-40 / 75-60, and 60-95 / 40-5, and by adjusting to such a range, the crystallinity and melting point of the polyester polyol are close to those of conventional ones. Productivity is also improved.

  The glycol and dibasic acid constituting the polyester polyol used in the present invention include combinations other than the above, but the total of the average number of carbon atoms of the glycol and the average number of carbon atoms of the dibasic acid is 6-7. A combination of .5 is preferred.

  The polyester polyol obtained from the glycol and the dibasic acid may have a number average molecular weight in the range of 1,000 to 200,000, more preferably 1000 to 5000, basically a hydroxyl-terminated polyester, and a number average molecular weight of 1200. Those having ˜4000 are particularly preferably used. By using a polyester polyol having a number average molecular weight in such a range, a retardation control agent (cellulose ester modifier) excellent in compatibility with the cellulose ester can be obtained by solid phase reaction.

  In obtaining the effect of the present invention, the polyester polyol having a number average molecular weight of 1000 or more is preferably contained in the film in an amount of 2 to 30% by mass from the viewpoint of retardation development, compatibility, moisture permeability, and the like. More preferably, it is 10-20 mass%. Actually, the content of the polymer in the film depends on the type of polymer and the weight average molecular weight, and the performance such as dimensional stability, retentivity, and transmittance is within the range in which dope, web, and phase separation do not occur after film formation. It is decided accordingly.

  On the other hand, the content of the carboxyl group terminal in the polyester polyol used in the present invention is preferably 1/20 or less of the number of moles of the hydroxyl terminal from the viewpoint of the effect of the present invention. It is more preferable to stop at 40 or less.

  In producing the polyester polyol described above, conventionally known esterification catalysts such as metal organic acid salts or metal chelate compounds such as titanium, zinc, lead and zirconium, or antimony oxide can be used. As the esterification catalyst, for example, tetraisopropyl titanate, tetrabutyl titanate and the like are preferably used, and 0.0005 to 0.02 mass relative to 100 mass parts in total of glycol (a) and dibasic acid (b) used. Are preferably used.

  Polycondensation of the polyester polyol is performed by a conventional method. For example, a direct reaction between the dibasic acid and glycol, the dibasic acid or an alkyl ester thereof, for example, a polyesterification reaction or transesterification reaction between a dibasic acid methyl ester and a glycol, or a hot melt condensation method, Alternatively, it can be easily synthesized by any method of dehydrohalogenation reaction between acid chlorides of these acids and glycols, but polyester polyols whose number average molecular weight is not so large are preferably by direct reaction. The polyester polyol having a high distribution on the low molecular weight side has very good compatibility with the cellulose ester, and after forming the film, a water vapor permeability is small, and a cellulose ester film rich in transparency can be obtained. A conventional method can be used as a method for adjusting the molecular weight without particular limitation. For example, although depending on the polymerization conditions, the amount of these monovalent compounds can be controlled by a method of blocking the molecular ends with a monovalent acid or monovalent alcohol. In this case, a monovalent acid is preferable from the viewpoint of polymer stability. For example, acetic acid, propionic acid, butyric acid, pivalic acid, benzoic acid and the like can be mentioned, but during the polycondensation reaction, such monovalent acid is not removed from the system but stopped and removed from the reaction system. Those which are easy to be distilled off when being removed from the system are selected, but these may be mixed and used. In the case of direct reaction, the number average molecular weight can also be adjusted by measuring the timing at which the reaction is stopped by the amount of water distilled off during the reaction. In addition, it can be adjusted by biasing the number of moles of glycol or dibasic acid to be charged or by controlling the reaction temperature.

<Ester of aromatic dicarboxylic acid and alkylene glycol>
As the phase difference controlling agent according to the present invention, an aromatic terminal ester plasticizer represented by the following general formula (I) can be used.

General formula (I) B- (GA) n-GB
(In the formula, B is a benzene monocarboxylic acid residue, G is an alkylene glycol residue having 2 to 12 carbon atoms, an aryl glycol residue having 6 to 12 carbon atoms, or an oxyalkylene glycol residue having 4 to 12 carbon atoms, A represents an alkylene dicarboxylic acid residue having 4 to 12 carbon atoms or an aryl dicarboxylic acid residue having 6 to 12 carbon atoms, and n represents an integer of 1 or more.)
In the general formula (I), a benzene monocarboxylic acid residue represented by B and an alkylene glycol residue, oxyalkylene glycol residue or aryl glycol residue represented by G, an alkylene dicarboxylic acid residue or aryl dicarboxylic group represented by A It is composed of an acid residue and can be obtained by a reaction similar to that of a normal polyester plasticizer.

  Examples of the benzene monocarboxylic acid component of the aromatic terminal ester plasticizer according to the present invention include, for example, benzoic acid, para-tert-butylbenzoic acid, orthotoluic acid, metatoluic acid, p-toluic acid, dimethylbenzoic acid, ethylbenzoic acid, normal There are propylbenzoic acid, aminobenzoic acid, acetoxybenzoic acid and the like, and these can be used as one kind or a mixture of two or more kinds, respectively.

  Examples of the alkylene glycol component having 2 to 12 carbon atoms of the aromatic terminal ester plasticizer include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, and 1,3-butanediol. 2-methyl 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2,2-diethyl-1 , 3-propanediol (3,3-dimethylolpentane), 2-n-butyl-2-ethyl-1,3-propanediol (3,3-dimethylolheptane), 3-methyl-1,5-pentanediol 1,6-hexanediol, 2,2,4-trimethyl 1,3-pentanediol, 2-ethyl 1,3-hexanediol There are 2-methyl 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-octadecanediol, etc., and these glycols are used as one kind or a mixture of two or more kinds. The

  Examples of the oxyalkylene glycol component having 4 to 12 carbon atoms of the aromatic terminal ester include diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, and tripropylene glycol. Or it can be used as a mixture of two or more.

  In addition, examples of the aryl glycol component having 6 to 12 carbon atoms of the aromatic terminal ester include hydroquinone, resorcin, bisphenol A, bisphenol F, bisphenol and the like, and these glycols are used as one kind or a mixture of two or more kinds. Can be used.

  Examples of the alkylene dicarboxylic acid component having 4 to 12 carbon atoms of the aromatic terminal ester of the present invention include succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, and dodecanedicarboxylic acid. These are each used as one or a mixture of two or more. Examples of the aryl dicarboxylic acid component having 6 to 12 carbon atoms include phthalic acid, terephthalic acid, 1,5 naphthalene dicarboxylic acid, and 1,4 naphthalene dicarboxylic acid.

  The aromatic terminal ester plasticizer has a number average molecular weight of preferably 300 to 2000, more preferably 500 to 1500. The acid value is preferably 0.5 mgKOH / g or less, the hydroxyl value is 25 mgKOH / g or less, more preferably the acid value is 0.3 mgKOH / g or less, and the hydroxyl value is 15 mgKOH / g or less.

<< Acid value and hydroxyl value of aromatic terminal ester >>
“Acid value” refers to the number of milligrams of potassium hydroxide necessary to neutralize the acid (carboxyl group present at the molecular terminal) contained in 1 g of a sample. The acid value and the hydroxyl value are measured according to JIS K0070.

  Hereinafter, the synthesis example of the aromatic terminal ester plasticizer which concerns on this invention is shown.

<Sample No. 1 (Aromatic terminal ester sample)>
Into a reaction vessel, 820 parts (5 moles) of phthalic acid, 608 parts (8 moles) of 1,2-propylene glycol, 610 parts (5 moles) of benzoic acid and 0.30 parts of tetraisopropyl titanate as a catalyst are charged all at once. While stirring in an air stream, a reflux condenser was attached to reflux excess monohydric alcohol, and heating was continued at 130 to 250 ° C. until the acid value became 2 or less, and water produced was continuously removed. Next, the distillate is removed under reduced pressure of 6.65 × 10 ³ Pa to 4 × 10 ² Pa or less at 200 to 230 ° C., followed by filtration to obtain an aromatic terminal ester having the following properties. It was.

Viscosity (25 ° C., mPa · s); 19815
Acid value: 0.4
<Sample No. 2 (Aromatic terminal ester sample)>
A sample was used except that 500 parts (3.5 moles) of adipic acid, 305 parts (2.5 moles) of benzoic acid, 583 parts (5.5 moles) of diethylene glycol and 0.45 parts of tetraisopropyl titanate as a catalyst were used in the reaction vessel. No. In the same manner as in No. 1, an aromatic terminal ester having the following properties was obtained.

Viscosity (25 ° C., mPa · s); 90
Acid value: 0.05
<Sample No. 3 (Aromatic terminal ester sample)>
Except for using 570 parts (3.5 mol) of isophthalic acid, 305 parts (2.5 mol) of benzoic acid, 737 parts (5.5 mol) of dipropylene glycol and 0.40 part of tetraisopropyl titanate as a catalyst in the reaction vessel. Sample No. In the same manner as in No. 1, an aromatic terminal ester having the following properties was obtained.

Viscosity (25 ° C., mPa · s); 33400
Acid value: 0.2
Although the specific compound of the aromatic terminal ester plasticizer which concerns on this invention below is shown, this invention is not limited to this.

  The content of the aromatic terminal ester plasticizer according to the present invention is preferably 1 to 20% by mass, and particularly preferably 3 to 11% by mass in the cellulose ester film.

<Polyhydric alcohol ester>
In the present invention, a polyhydric alcohol ester plasticizer can be further used as the retardation control agent.

  The polyhydric alcohol ester used in the present invention is composed of an ester of a dihydric or higher aliphatic polyhydric alcohol and a monocarboxylic acid, and preferably has an aromatic ring or a cycloalkyl ring in the molecule.

  The polyhydric alcohol used in the present invention is represented by the following general formula (1).

Formula (1) R1- (OH) _n
In the formula, R1 represents an n-valent organic group, n represents a positive integer of 2 or more, and the OH group represents an alcoholic or phenolic hydroxyl group.

  Examples of preferred polyhydric alcohols include the following, but the present invention is not limited to these. Adonitol, arabitol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1,2-butanediol, 1,3- Butanediol, 1,4-butanediol, dibutylene glycol, 1,2,4-butanetriol, 1,5-pentanediol, 1,6-hexanediol, hexanetriol, galactitol, mannitol, 3-methylpentane- Examples include 1,3,5-triol, pinacol, sorbitol, trimethylolpropane, trimethylolethane, and xylitol. Of these, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, sorbitol, trimethylolpropane, and xylitol are preferable.

  There is no restriction | limiting in particular as monocarboxylic acid used for the polyhydric alcohol ester of this invention, Well-known aliphatic monocarboxylic acid, alicyclic monocarboxylic acid, aromatic monocarboxylic acid, etc. can be used. Use of an alicyclic monocarboxylic acid or aromatic monocarboxylic acid is preferable in terms of improving moisture permeability and retention. Examples of preferred monocarboxylic acids include the following, but the present invention is not limited thereto.

  As the aliphatic monocarboxylic acid, a fatty acid having a straight chain or a side chain having 1 to 32 carbon atoms can be preferably used. It is more preferable that it is C1-C20, and it is especially preferable that it is C1-C10. The use of acetic acid is preferred because the compatibility with the cellulose ester is increased, and it is also preferred to use a mixture of acetic acid and another monocarboxylic acid.

  Preferred aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, 2-ethyl-hexanecarboxylic acid, undecylic acid, lauric acid, tridecylic acid , Saturated fatty acids such as myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, heptacosanoic acid, montanic acid, melicic acid, laccelic acid, undecylenic acid, Examples thereof include unsaturated fatty acids such as oleic acid, sorbic acid, linoleic acid, linolenic acid and arachidonic acid. Examples of preferable alicyclic monocarboxylic acids include cyclopentanecarboxylic acid, cyclohexanecarboxylic acid, cyclooctanecarboxylic acid, and derivatives thereof. Examples of preferred aromatic monocarboxylic acids include those in which an alkyl group is introduced into the benzene ring of benzoic acid such as benzoic acid and toluic acid, and two or more benzene rings such as biphenyl carboxylic acid, naphthalene carboxylic acid, and tetralin carboxylic acid. Aromatic monocarboxylic acids possessed by them, or derivatives thereof. In particular, benzoic acid is preferred.

  The molecular weight of the polyhydric alcohol ester is not particularly limited, but is preferably in the range of 300 to 1500, and more preferably in the range of 350 to 750. A higher molecular weight is preferred because it is less likely to volatilize, and a smaller one is preferred in terms of moisture permeability and compatibility with cellulose ester. The carboxylic acid used for the polyhydric alcohol ester may be one kind or a mixture of two or more kinds. Moreover, all the OH groups in the polyhydric alcohol may be esterified, or a part of the OH groups may be left as they are. The specific compound of a polyhydric alcohol ester is shown below.

<Sugar benzoate>
As the retardation control agent according to the present invention, an esterified compound obtained by esterifying all or part of the OH group in the (meth) acrylic polymer and the compound (A) having one furanose structure or one pyranose structure, Alternatively, it is also preferable to use an esterified compound obtained by esterifying all or part of the OH groups in the compound (B) in which 2 or more and 12 or less of at least one of a furanose structure or a pyranose structure are bonded. In the present application, the esterified compound of the compound (A) and the esterified compound of the compound (B) according to the present invention are collectively referred to as a sugar ester compound.

The ester compound is a monosaccharide (α-glucose, β-fructose) benzoate or a monosaccharide represented by the following general formula (A): —OR ₁₂ , —OR ₁₅ , —OR ₂₂ , —OR It is preferable that the benzoic acid ester of the polysaccharide of m + n = 2-12 produced | generated by dehydration condensation of ₂₅ or more arbitrary places.

  The benzoic acid in the above general formula may further have a substituent, for example, an alkyl group, an alkenyl group, an alkoxyl group, and a phenyl group, and these alkyl group, alkenyl group, and phenyl group have a substituent. You may have.

  Examples of the preferred compound (A) and compound (B) include the following, but the present invention is not limited to these.

  Examples of the compound (A) include glucose, galactose, mannose, fructose, xylose, or arabinose.

  Examples of the compound (B) include lactose, sucrose, nystose, 1F-fructosyl nystose, stachyose, maltitol, lactitol, lactulose, cellobiose, maltose, cellotriose, maltotriose, raffinose or kestose. In addition, gentiobiose, gentiotriose, gentiotetraose, xylotriose, galactosyl sucrose, and the like are also included. Of these compounds (A) and (B), compounds having both a furanose structure and a pyranose structure are particularly preferable. Examples include sucrose, kestose, nystose, 1F-fructosyl nystose, stachyose, and more preferably sucrose. In addition, in the compound (B), a compound in which at least one of a furanose structure or a pyranose structure is bonded in an amount of 2 or more and 3 or less is also a preferred embodiment.

  The monocarboxylic acid used for esterifying all or part of the OH groups in the compound (A) and the compound (B) according to the present invention is not particularly limited, and known aliphatic monocarboxylic acids and fats A cyclic monocarboxylic acid, an aromatic monocarboxylic acid, or the like can be used. The carboxylic acid used may be one type or a mixture of two or more types.

  Preferred aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, 2-ethyl-hexanecarboxylic acid, undecylic acid, lauric acid , Saturated fatty acids such as tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, heptacosanoic acid, montanic acid, melicic acid, and laccelic acid, Examples include unsaturated fatty acids such as undecylenic acid, oleic acid, sorbic acid, linoleic acid, linolenic acid, arachidonic acid and octenoic acid.

  Examples of preferred alicyclic monocarboxylic acids include cyclopentane carboxylic acid, cyclohexane carboxylic acid, cyclooctane carboxylic acid, or derivatives thereof.

  Examples of preferred aromatic monocarboxylic acids include aromatic monocarboxylic acids having an alkyl group or alkoxy group introduced into the benzene ring of benzoic acid such as benzoic acid and toluic acid, cinnamic acid, benzylic acid, biphenylcarboxylic acid, and naphthalene. Examples thereof include aromatic monocarboxylic acids having two or more benzene rings such as carboxylic acid and tetralin carboxylic acid, or derivatives thereof. More specifically, xylyl acid, hemelic acid, mesitylene acid, prenylic acid, γ-isoduric acid, jurylic acid, mesitic acid, α-isoduric acid, cumic acid, α-toluic acid, hydroatropic acid, atropic acid, hydrocinnamic acid, salicylic acid, o-anisic acid, m-anisic acid, p-anisic acid , Creosote acid, o-homosalicylic acid, m-homosalicylic acid, p-homosalicylic acid, o-pyroca Succinic acid, β-resorcylic acid, vanillic acid, isovanillic acid, veratromic acid, o-veratrumic acid, gallic acid, asaronic acid, mandelic acid, homoanisic acid, homovanillic acid, homoveratrumic acid, o-homoveratrumic acid, phthalonic acid, p- Although coumaric acid can be mentioned, benzoic acid is particularly preferable.

  Among the esterified compounds obtained by esterifying the compound (A) and the compound (B), an acetylated compound having an acetyl group introduced by esterification is preferable.

  A method for producing these acetylated compounds is described, for example, in JP-A-8-245678.

  In addition to the esterified compounds of the compounds (A) and (B), the oligosaccharide esterified compound can be applied as a compound in which 3 to 12 of the furanose structure or the pyranose structure according to the present invention are bonded. .

  Oligosaccharides are produced by allowing an enzyme such as amylase to act on starch, sucrose, etc. Examples of oligosaccharides that can be applied to the present invention include maltooligosaccharides, isomaltoligosaccharides, fructooligosaccharides, galactooligosaccharides, xylooligos. Sugar.

  Oligosaccharides can also be acetylated in the same manner as the above compounds (A) and (B).

  Next, an example of a production example of an esterified compound will be described.

  Acetic anhydride (200 ml) was added dropwise to a solution obtained by adding pyridine (100 ml) to glucose (29.8 g, 166 mmol), and allowed to react for 24 hours. Thereafter, the solution was concentrated by evaporation and poured into ice water. After standing for 1 hour, the mixture was filtered through a glass filter to separate the solid and water. The solid on the glass filter was dissolved in chloroform and separated with cold water until it became neutral. The organic layer was separated and dried over anhydrous sodium sulfate. After removing anhydrous sodium sulfate by filtration, chloroform was removed by evaporation, and further dried under reduced pressure to obtain glycolose pentaacetate (58.8 g, 150 mmol, 90.9%). In addition, the above-mentioned monocarboxylic acid can be used instead of the acetic anhydride.

  Specific examples of the esterified compound according to the present invention are listed below, but the present invention is not limited thereto.

  The optical compensation film of the present invention contains a furanose structure or a pyranose in a compound (A) having one furanose structure or a pyranose structure in order to stabilize the display quality by suppressing the fluctuation of the retardation value. It is preferable to contain 1 to 30% by mass of an esterified compound obtained by esterifying all or part of the OH group in the compound (B) in which 2 to 12 of at least one of the structures are bonded, and in particular, 5 to 30% by mass. % Is preferable. Within this range, it is preferable that the excellent effects of the present invention are exhibited and there is no bleeding out.

  Further, in a compound (A) having a (meth) acrylic polymer and one furanose structure or one pyranose structure, or in a compound (B) in which 2 to 12 at least one kind of furanose structure or pyranose structure is bonded. An esterified compound obtained by esterifying all or a part of the OH group may be used in combination with another plasticizer.

<Other phase difference control agents>
As the phase difference controlling agent according to the present invention, those containing bisphenol A in the molecule are also preferred. A compound in which ethylene oxide or propylene oxide is added to both ends of bisphenol A can be used.

  For example, BP series such as New Pole BP-2P, BP-3P, BP-23P, BP-5P, BPE-20 (F), BPE-20NK, BPE-20T, BPE-40, BPE-60, BPE-100, There are BPE series (manufactured by Sanyo Chemical Co., Ltd.) such as BPE-180, and BPX series (manufactured by Adeka Co., Ltd.) such as Adeka polyether BPX-11, BPX-33, BPX-55.

  Diallyl bisphenol A, dimethallyl bisphenol A, tetrabromobisphenol A with bisphenol A substituted with bromine, oligomers and polymers obtained by polymerizing this, bisphenol A bis (diphenyl phosphate) substituted with diphenyl phosphate, etc. Can be used.

  Polycarbonate obtained by polymerizing bisphenol A, polyarylate obtained by polymerizing bisphenol A with a dibasic acid such as terephthalic acid, and an epoxy oligomer or polymer polymerized with an epoxy-containing monomer can also be used.

  Modiper CL130D or L440-G obtained by graft polymerization of bisphenol A and styrene, styrene acrylic, or the like can also be used.

  The optical film according to the present invention can also contain two or more retardation control agents. In this case, by optimizing the combination, elution of the phase difference controlling agent can be reduced. The reason is not clear, but it seems that elution is suppressed by the ability to reduce the amount added per type and the interaction between the two phase difference control agents and the acrylic resin-containing composition.

<Other additives>
In the optical film of the present invention, a plasticizer can be used in combination in order to improve the fluidity and flexibility of the composition. Examples of the plasticizer include phthalate ester, fatty acid ester, trimellitic ester, phosphate ester, polyester, and epoxy.

  For phosphate plasticizers, triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenylbiphenyl phosphate, trioctyl phosphate, tributyl phosphate, etc. For phthalate ester plasticizers, diethyl phthalate, dimethoxy Ethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate and the like can be used.

  Of these, polyester and phthalate plasticizers are preferably used. Polyester plasticizers are superior in non-migration and extraction resistance compared to phthalate ester plasticizers such as dioctyl phthalate, but are slightly inferior in plasticizing effect and compatibility.

  Therefore, it can be applied to a wide range of uses by selecting or using these plasticizers according to the use.

  The polyester plasticizer is a reaction product of a monovalent or tetravalent carboxylic acid and a monovalent or hexavalent alcohol, and is mainly obtained by reacting a divalent carboxylic acid with a glycol. . Representative divalent carboxylic acids include glutaric acid, itaconic acid, adipic acid, phthalic acid, azelaic acid, sebacic acid and the like.

  In particular, when adipic acid, phthalic acid or the like is used, those having excellent plasticizing properties can be obtained. Examples of the glycol include glycols such as ethylene, propylene, 1,3-butylene, 1,4-butylene, 1,6-hexamethylene, neopentylene, diethylene, triethylene, and dipropylene. These divalent carboxylic acids and glycols may be used alone or in combination.

  The ester plasticizer may be any of ester, oligoester and polyester types, and the molecular weight is preferably in the range of 100 to 10000, but preferably in the range of 600 to 3000, the plasticizing effect is large.

  The viscosity of the plasticizer has a correlation with the molecular structure and molecular weight. In the case of an adipic acid plasticizer, the viscosity is preferably in the range of 200 to 5000 mPa · s (25 ° C.) in view of compatibility and plasticization efficiency. Furthermore, some polyester plasticizers may be used in combination.

    The plasticizer is preferably added in an amount of 0.5 to 30 parts by mass with respect to 100 parts by mass of the composition containing an acrylic resin. If the added amount of the plasticizer exceeds 30 parts by mass, the surface becomes sticky, which is not preferable for practical use. These plasticizers may be used alone or in combination of two or more.

  Furthermore, various antioxidants can be added to the acrylic resin used in the optical film of the present invention in order to improve the thermal decomposability and thermal colorability during molding. It is also possible to add an antistatic agent to give the optical film antistatic performance.

  As the acrylic resin composition of the present invention, a flame retardant acrylic resin composition containing a phosphorus flame retardant may be used.

  Phosphorus flame retardants used here include red phosphorus, triaryl phosphate ester, diaryl phosphate ester, monoaryl phosphate ester, aryl phosphonate compound, aryl phosphine oxide compound, condensed aryl phosphate ester, halogenated alkyl phosphorus. Examples thereof include one or a mixture of two or more selected from acid esters, halogen-containing condensed phosphates, halogen-containing condensed phosphonates, halogen-containing phosphites, and the like.

  Specific examples include triphenyl phosphate, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, phenylphosphonic acid, tris (β-chloroethyl) phosphate, tris (dichloropropyl). Examples thereof include phosphate and tris (tribromoneopentyl) phosphate.

<Optical film formation>
An example of a method for producing an optical film will be described, but the present invention is not limited to this.

  As a method for forming the optical film of the present invention, production methods such as an inflation method, a T-die method, a calendar method, a cutting method, a casting method, an emulsion method, and a hot press method can be used. From the standpoint of suppressing optical defects such as die lines and optical defects such as die lines, solution casting by casting is preferred.

(Organic solvent)
The organic solvent useful for forming the dope when the optical film of the present invention is produced by the solution casting method is not limited as long as it dissolves acrylic resin, cellulose ester resin, and other additives at the same time. I can do it.

  For example, as the chlorinated organic solvent, methylene chloride, as the non-chlorinated organic solvent, methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, ethyl formate, 2,2,2-trifluoroethanol, 2,2,3,3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1,1,1,3,3,3-hexafluoro- Examples include 2-methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro-1-propanol, and nitroethane. Methylene chloride, methyl acetate, ethyl acetate and acetone can be preferably used.

  In addition to the organic solvent, the dope preferably contains 1 to 40% by mass of a linear or branched aliphatic alcohol having 1 to 4 carbon atoms. When the proportion of alcohol in the dope increases, the web gels and peeling from the metal support becomes easy, and when the proportion of alcohol is small, the acrylic resin and cellulose ester resin dissolve in a non-chlorine organic solvent system. There is also a role to promote.

  In particular, in a solvent containing methylene chloride and a linear or branched aliphatic alcohol having 1 to 4 carbon atoms, at least 15 to 45 mass in total of at least three kinds of acrylic resin, cellulose ester resin, and acrylic particles are used. It is preferable that the dope composition is dissolved in%.

  Examples of the linear or branched aliphatic alcohol having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, and tert-butanol. Ethanol is preferred because of the stability of these dopes, the relatively low boiling point, and good drying properties.

  Hereinafter, the preferable film forming method of the optical film of the present invention will be described.

1) Dissolution process In an organic solution mainly composed of a good solvent for acrylic resin and cellulose ester resin, the acrylic resin, cellulose ester resin, and in some cases acrylic particles, and other additives are dissolved in a dissolution vessel while stirring. The step of forming, or the step of forming a dope which is a main solution by mixing the acrylic resin or cellulose ester resin solution with an acrylic particle solution or other additive solution as the case may be.

  For dissolution of acrylic resin and cellulose ester resin, a method performed at normal pressure, a method performed below the boiling point of the main solvent, a method performed under pressure above the boiling point of the main solvent, JP-A-9-95544, JP-A-9- Various dissolution methods can be used such as a method performed by a cooling dissolution method as described in JP-A-95557 or JP-A-9-95538, a method performed at high pressure as described in JP-A No. 11-21379, In particular, a method of pressurizing at a temperature equal to or higher than the boiling point of the main solvent is preferable.

  The total amount of the acrylic resin and the cellulose ester resin in the dope is preferably 15 to 45% by mass. An additive is added to the dope during or after dissolution to dissolve and disperse, then filtered through a filter medium, defoamed, and sent to the next step with a liquid feed pump.

  Filtration is preferably performed using a filter medium having a collected particle size of 0.5 to 5 μm and a drainage time of 10 to 25 sec / 100 ml.

  In this method, the aggregate remaining at the time of particle dispersion and the aggregate generated when the main dope is added are only aggregated by using a filter medium having a collected particle diameter of 0.5 to 5 μm and a drainage time of 10 to 25 sec / 100 ml. Can be removed. In the main dope, the concentration of particles is sufficiently thinner than that of the additive solution, so that aggregates do not stick together at the time of filtration and the filtration pressure does not increase suddenly.

  FIG. 1 is a diagram schematically showing a dope preparation step, a casting step, and a drying step of a solution casting film forming method preferable for the present invention.

  If necessary, large agglomerates are removed from the acrylic particle charging kettle 41 by the filter 44 and fed to the stock kettle 42. Thereafter, the acrylic particle additive solution is added from the stock kettle 42 to the main dope dissolving kettle 1.

  Thereafter, the main dope solution is filtered by the main filter 3, and an ultraviolet absorbent additive solution is added in-line from 16 to this.

  In many cases, the main dope may contain about 10 to 50% by mass of the recycled material. The return material may contain acrylic particles. In that case, it is preferable to control the addition amount of the acrylic particle addition liquid in accordance with the addition amount of the return material.

  The additive solution containing acrylic particles preferably contains 0.5 to 10% by mass of acrylic particles, more preferably 1 to 10% by mass, and 1 to 5% by mass. Most preferably.

  The above range is preferable because the smaller the acrylic particle content, the lower the viscosity and the easier the handling, and the higher the acrylic particle content, the smaller the addition amount and the easier the addition to the main dope.

  The return material is a product obtained by finely pulverizing the optical film, which is generated when the optical film is formed, and is obtained by cutting off both sides of the film, or by using an optical film original that has been speculated out due to scratches, etc. .

  In addition, an acrylic resin, a cellulose ester resin, and, in some cases, acrylic particles kneaded into pellets can be preferably used.

2) Casting process An endless metal belt 31, such as a stainless steel belt or a rotating metal drum, which feeds the dope through a liquid feed pump (for example, a pressurized metering gear pump) to the pressure die 30 and transfers it infinitely. This is a step of casting the dope from the pressure die slit to the casting position on the support.

  A pressure die that can adjust the slit shape of the die base and facilitates uniform film thickness is preferred. The pressure die includes a coat hanger die and a T die, and any of them is preferably used. The surface of the metal support is a mirror surface. In order to increase the film forming speed, two or more pressure dies may be provided on the metal support, and the dope amount may be divided and stacked. Or it is also preferable to obtain the film of a laminated structure by the co-casting method which casts several dope simultaneously.

3) Solvent evaporation step In this step, the web (the dope is cast on the casting support and the formed dope film is called a web) is heated on the casting support to evaporate the solvent.

  To evaporate the solvent, there are a method of blowing air from the web side and / or a method of transferring heat from the back side of the support by a liquid, a method of transferring heat from the front and back by radiant heat, and the like. High efficiency and preferable. A method of combining them is also preferably used. The web on the support after casting is preferably dried on the support in an atmosphere of 40 to 100 ° C. In order to maintain the atmosphere at 40 to 100 ° C., it is preferable to apply hot air at this temperature to the upper surface of the web or to heat by means such as infrared rays.

  From the viewpoint of surface quality, moisture permeability, and peelability, it is preferable to peel the web from the support within 30 to 120 seconds.

4) Peeling process It is the process of peeling the web which the solvent evaporated on the metal support body in a peeling position. The peeled web is sent to the next process.

  The temperature at the peeling position on the metal support is preferably 10 to 40 ° C, more preferably 11 to 30 ° C.

  The residual solvent amount at the time of peeling of the web on the metal support at the time of peeling is preferably peeled in the range of 50 to 120% by mass depending on the strength of drying conditions, the length of the metal support, and the like. When peeling off at a time when the amount of residual solvent is larger, if the web is too soft, the flatness at the time of peeling will be impaired, and slippage and vertical stripes are likely to occur due to peeling tension, so the balance between economic speed and quality The amount of residual solvent is determined.

  The residual solvent amount of the web is defined by the following formula.

Residual solvent amount (%) = (mass before web heat treatment−mass after web heat treatment) / (mass after web heat treatment) × 100
Note that the heat treatment for measuring the residual solvent amount represents performing heat treatment at 115 ° C. for 1 hour.

  The peeling tension at the time of peeling the metal support and the film is usually 196 to 245 N / m. However, when wrinkles easily occur at the time of peeling, it is preferable to peel with a tension of 190 N / m or less. It is preferable to peel at a minimum tension that can be peeled to 166.6 N / m, and then peel at a minimum tension to 137.2 N / m, and particularly preferably peel at a minimum tension to 100 N / m.

  In the present invention, the temperature at the peeling position on the metal support is preferably -50 to 40 ° C, more preferably 10 to 40 ° C, and most preferably 15 to 30 ° C.

5) Drying and stretching step After peeling, a drying device 35 that alternately conveys the web through a plurality of rolls arranged in the drying device and / or a tenter stretching device 34 that clips and conveys both ends of the web with a clip are used. And dry the web.

  Generally, the drying means blows hot air on both sides of the web, but there is also a means for heating by applying microwaves instead of the wind. Too rapid drying tends to impair the flatness of the finished film. Drying at a high temperature is preferably performed from about 8% by mass or less of the residual solvent. Throughout the drying is generally carried out at 40-250 ° C. It is particularly preferable to dry at 40 to 160 ° C.

  When a tenter stretching apparatus is used, it is preferable to use an apparatus that can independently control the film gripping length (distance from the start of gripping to the end of gripping) by the left and right gripping means of the tenter. In the tenter process, it is also preferable to intentionally create sections having different temperatures in order to improve planarity.

  It is also preferable to provide a neutral zone between different temperature zones so that the zones do not interfere with each other.

  The stretching operation may be performed in multiple stages, and it is also preferable to perform biaxial stretching in the casting direction and the width direction. When biaxial stretching is performed, simultaneous biaxial stretching may be performed or may be performed stepwise.

  In this case, stepwise means that, for example, stretching in different stretching directions can be sequentially performed, stretching in the same direction is divided into multiple stages, and stretching in different directions is added to any one of the stages. Is also possible. That is, for example, the following stretching steps are possible.

-Stretch in the casting direction-Stretch in the width direction-Stretch in the casting direction-Stretch in the casting direction-Stretch in the width direction-Stretch in the width direction-Stretch in the casting direction-Stretch in the casting direction Simultaneous biaxial stretching includes stretching in one direction and contracting the other while relaxing the tension. The preferable draw ratio of simultaneous biaxial stretching can be taken in the range of x1.01 to x1.5 times in both the width direction and the longitudinal direction.

  When the tenter is used, the residual solvent amount of the web is preferably 20 to 100% by mass at the start of the tenter, and it is preferable to perform drying while applying the tenter until the residual solvent amount of the web becomes 10% by mass or less. More preferably, it is 5% by mass or less.

  30-150 degreeC is preferable, as for the drying temperature in the case of performing a tenter, 50-120 degreeC is more preferable, and 70-100 degreeC is the most preferable.

  In the tenter process, it is preferable that the temperature distribution in the width direction of the atmosphere is small from the viewpoint of improving the uniformity of the film. The temperature distribution in the width direction in the tenter process is preferably within ± 5 ° C, and within ± 2 ° C. Is more preferable, and within ± 1 ° C is most preferable.

6) Winding step This is a step of winding the optical film by the winder 37 after the residual solvent amount in the web is 2% by mass or less, and the dimensional stability is achieved by setting the residual solvent amount to 0.4% by mass or less. A film with good properties can be obtained.

  As a winding method, a generally used method may be used. There are a constant torque method, a constant tension method, a taper tension method, a program tension control method with a constant internal stress, and the like.

  The optical film of the present invention is preferably a long film. Specifically, the optical film has a thickness of about 100 m to 5000 m and is usually provided in a roll shape. Moreover, it is preferable that the width | variety of a film is 1.3-4m, and it is more preferable that it is 1.4-2m.

  Although there is no restriction | limiting in particular in the film thickness of the optical film of this invention, When using for the polarizing plate protective film mentioned later, it is preferable that it is 20-200 micrometers, it is more preferable that it is 25-100 micrometers, and it is 30-80 micrometers. It is particularly preferred.

(Physical properties of optical films)
Hereinafter, the characteristics of the optical film according to the present invention will be described.

<Photoelastic coefficient>
The optical film of the present invention is preferably adjusted so that the photoelastic coefficient is −5 × 10 ^{−12 to} 5 × 10 ⁻¹² / Pa.

  In the present invention, the photoelastic coefficient is adjusted within the above range by adjusting the ratio of the acrylic resin and the cellulose ester resin within the mass ratio of 51:49 to 95: 5. According to the ratio, the combination of the retardation control agent and the amount to be added are adjusted to optimize the composition of the optical film.

  Even if stress is applied to the retardation film when the liquid crystal display device is turned on for a long time by adjusting the photoelastic coefficient to such a range and the panel becomes high temperature or the surrounding atmosphere becomes high temperature and high humidity. The phase difference is less likely to occur and image unevenness can be reduced. Furthermore, image unevenness that occurs when used for a long time can also be reduced.

<Others>
The optical film according to the present invention has a tension softening point of 105 ° C. when considering use in a high-temperature environment such as a projector having a high haze and a high temperature such as a projector or a vehicle-mounted display device. It is preferable to set it to -145 degreeC, and it is more preferable to control to 110 to 130 degreeC.

  As a specific method for measuring the tension softening point temperature of the optical film, for example, a Tensilon tester (ORIENTEC, RTC-1225A) is used, and the optical film is cut into 120 mm (length) × 10 mm (width) and 10 N The temperature can be increased at a rate of temperature increase of 30 ° C./min while pulling with a tension of 30 ° C., and the temperature at 9 N is measured three times, and the average value can be obtained.

  The optical film of the present invention preferably has a glass transition temperature (Tg) of 110 ° C. or higher. More preferably, it is 120 ° C. or higher. Especially preferably, it is 150 degreeC or more.

  The glass transition temperature referred to here is an intermediate value determined according to JIS K7121 (1987) using a differential scanning calorimeter (DSC-7 model manufactured by Perkin Elmer) at a temperature rising rate of 20 ° C./min. Point glass transition temperature (Tmg).

  In the optical film of the present invention, the number of defects within a film plane of 5 μm or more is 1/10 cm square or less. More preferably, it is 0.5 piece / 10 cm square or less, more preferably 0.1 piece / 10 cm square or less.

  Here, the diameter of the defect indicates the diameter when the defect is circular, and when the defect is not circular, the range of the defect is determined by observing with a microscope by the following method, and the maximum diameter (diameter of circumscribed circle) is determined.

  The range of the defect is the size of the shadow when the defect is observed with the transmitted light of the differential interference microscope when the defect is a bubble or a foreign object. When the defect is a change in the surface shape, such as transfer of a roll flaw or an abrasion, the size is confirmed by observing the defect with the reflected light of a differential interference microscope.

  In addition, when observing with reflected light, if the size of the defect is unclear, aluminum or platinum is deposited on the surface for observation.

  In order to obtain a film having excellent quality expressed by such a defect frequency with high productivity, it is necessary to filter the polymer solution with high precision immediately before casting, to increase the cleanliness around the casting machine, It is effective to set drying conditions after rolling stepwise and to dry efficiently while suppressing foaming.

  If the number of defects is greater than 1/10 cm square, for example, when the film is tensioned during processing in a later step, the film may break with the defects as a starting point, and productivity may be significantly reduced. Moreover, when the diameter of a defect becomes 5 micrometers or more, it can confirm visually by polarizing plate observation etc., and when used as an optical member, a bright spot may arise.

  Moreover, even when it cannot be visually confirmed, when a hard coat layer or the like is formed on the film, the coating agent may not be formed uniformly, resulting in a defect (missing coating). Here, the defect is a void in the film (foaming defect) generated due to the rapid evaporation of the solvent in the drying process of the solution casting, a foreign matter in the film forming stock solution, or a foreign matter mixed in the film forming. This refers to the foreign matter (foreign matter defect) in the film.

  In the measurement according to JIS-K7127-1999, the optical film of the present invention preferably has a breaking elongation in at least one direction of 10% or more, more preferably 20% or more.

  The upper limit of the elongation at break is not particularly limited, but is practically about 250%. In order to increase the elongation at break, it is effective to suppress defects in the film caused by foreign matter and foaming.

  The thickness of the optical film of the present invention is preferably 20 μm or more. More preferably, it is 30 μm or more.

  The upper limit of the thickness is not particularly limited, but in the case of forming a film by a solution casting method, the upper limit is about 250 μm from the viewpoint of applicability, foaming, solvent drying, and the like. The thickness of the film can be appropriately selected depending on the application.

  The optical film of the present invention preferably has a total light transmittance of 90% or more, more preferably 93% or more. Moreover, as a realistic upper limit, it is about 99%. In order to achieve excellent transparency expressed by such total light transmittance, it is necessary not to introduce additives and copolymerization components that absorb visible light, or to remove foreign substances in the polymer by high-precision filtration. It is effective to reduce the diffusion and absorption of light inside the film.

  Also, reduce the surface roughness of the film surface by reducing the surface roughness of the film contact part (cooling roll, calender roll, drum, belt, coating substrate in solution casting, transport roll, etc.) during film formation. It is also effective to reduce the diffusion and reflection of light on the film surface by reducing the refractive index of the acrylic resin.

  The optical film of the present invention is characterized in that the haze value (turbidity), which is one of the indexes indicating transparency, is 1.0% or less. However, the luminance and contrast when incorporated in a liquid crystal display device are characteristic. From the point, it is preferably 0.5% or less.

  In order to achieve such a haze value, it is effective to remove foreign substances in the polymer by high-precision filtration to reduce the diffusion of light inside the film.

  In the case of using acrylic particles, it is also effective to reduce the difference in refractive index between the acrylic resin and the acrylic particles.

  In addition, since the surface roughness also affects the haze value as surface haze, it is also effective to suppress the particle diameter and addition amount of acrylic particles within the above range, or to reduce the surface roughness of the film contact portion during film formation It is.

  In addition, the total light transmittance and haze value of the above optical film are values measured according to JIS-K7361-1-1997 and JIS-K7136-2000.

  The optical film of the present invention can be preferably used as an optical film as long as the above physical properties are satisfied, but a film excellent in workability and heat resistance can be obtained by using the following composition. be able to.

  That is, from the viewpoint of achieving both workability and heat resistance, the optical film contains an acrylic resin and a cellulose ester resin in a mass ratio of 95: 5 to 30:70, and the total substitution degree of acyl groups of the cellulose ester resin. (T) is 2.00 to 2.99, acetyl group substitution degree (ac) is 0.10 to 1.89, carbon number of acyl group other than acetyl group is 3 to 7, and weight average molecular weight (Mw) The optical film characterized in that is 75000 to 250,000, the excellent effect of the present invention can be obtained.

  In the optical film of the present invention, the acrylic resin and the cellulose ester resin are contained in a mass ratio of 95: 5 to 30:70, and the acrylic resin is preferably 50% by mass or more.

  The optical film of the present invention may contain a resin other than acrylic resin and cellulose ester resin.

  The total mass of the acrylic resin and the cellulose ester resin is 55 to 100% by mass of the optical film, and preferably 60 to 99% by mass.

(Polarizer)
The polarizing plate according to the present invention can be produced by a general method. It is preferable that an adhesive layer is provided on the back side of the optical film of the present invention, and is bonded to at least one surface of a polarizer produced by immersion and stretching in an iodine solution.

  The film may be used on the other surface, or another polarizing plate protective film may be used. For example, commercially available cellulose ester films (for example, Konica Minoltack KC8UX, KC4UX, KC5UX, KC8UY, KC4UY, KC12UR, KC8UCR-3, KC8UCR-4, KC8UCR-5, KV8UY-HA, KV8UX-RHA, OP Etc.) are preferably used.

  A polarizer, which is a main component of a polarizing plate, is an element that transmits only light having a plane of polarization in a certain direction. A typical polarizing film known at present is a polyvinyl alcohol polarizing film, which is a polyvinyl alcohol. There are one in which iodine is dyed on a system film and one in which dichroic dye is dyed.

  For the polarizer, a polyvinyl alcohol aqueous solution is formed into a film and dyed by uniaxial stretching or dyed or uniaxially stretched and then preferably subjected to a durability treatment with a boron compound.

As the pressure-sensitive adhesive used for the pressure-sensitive adhesive layer, a pressure-sensitive adhesive having a storage elastic modulus at 25 ° C. in the range of 1.0 × 10 ⁴ Pa to 1.0 × 10 ⁹ Pa in at least a part of the pressure-sensitive adhesive layer is used. It is preferable to use a curable pressure-sensitive adhesive that forms a high molecular weight body or a crosslinked structure by various chemical reactions after the pressure-sensitive adhesive is applied and bonded.

  Specific examples include, for example, urethane adhesives, epoxy adhesives, aqueous polymer-isocyanate adhesives, curable adhesives such as thermosetting acrylic adhesives, moisture-curing urethane adhesives, polyether methacrylate types, Examples include anaerobic pressure-sensitive adhesives such as ester-based methacrylate type and oxidized polyether methacrylate, cyanoacrylate-based instantaneous pressure-sensitive adhesives, and acrylate-peroxide-based two-component instantaneous pressure-sensitive adhesives.

  The pressure-sensitive adhesive may be a one-component type or a type that is used by mixing two or more components before use.

  The pressure-sensitive adhesive may be a solvent system using an organic solvent as a medium, or an aqueous system such as an emulsion type, a colloidal dispersion type, or an aqueous solution type that is a medium containing water as a main component. It may be a solvent type. The density | concentration of the said adhesive liquid should just be suitably determined with the film thickness after adhesion, the coating method, the coating conditions, etc., and is 0.1-50 mass% normally.

(Liquid crystal display device)
By incorporating the polarizing plate bonded with the optical film of the present invention into a liquid crystal display device using at least one surface of the liquid crystal cell, liquid crystal display devices having various durability can be produced. The polarizing plate according to the present invention is bonded to a liquid crystal cell via the adhesive layer or the like.

  The polarizing plate according to the present invention is a reflective type, transmissive type, transflective type LCD or TN type, STN type, OCB type, HAN type, VA type (PVA type, MVA type), IPS type, etc. Preferably used.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

<Example 1>
(Acrylic resin (A))
The following commercially available products were used.
Dianar BR50 (Mitsubishi Rayon Co., Ltd.) Mw100,000
Dianar BR52 (Mitsubishi Rayon Co., Ltd.) Mw85000
Dianar BR80 (Mitsubishi Rayon Co., Ltd.) Mw95000
Dianar BR83 (Mitsubishi Rayon Co., Ltd.) Mw40000
Dianar BR85 (Mitsubishi Rayon Co., Ltd.) Mw280000
Dianar BR88 (manufactured by Mitsubishi Rayon Co., Ltd.) Mw 480000
80N (Asahi Kasei Chemicals Corporation) Mw100,000
The proportion of MMA units in the molecule in the above-mentioned commercially available acrylic resin was about 30% by mass for Dialal BR50, about 70% by mass for Dialal BR52, and 90% to 99% by mass for all of Dialal BR80 to 80N. It was.

<Preparation of acrylic particles (C1)>
A reactor with a reflux condenser with an internal volume of 60 liters was charged with 38.2 liters of ion-exchanged water and 111.6 g of sodium dioctylsulfosuccinate, and the temperature was raised to 75 ° C. under a nitrogen atmosphere while stirring at a rotational speed of 250 rpm. The effect of oxygen was virtually eliminated. 0.36 g of APS was added, and after stirring for 5 minutes, a monomer mixture consisting of 1657 g of MMA, 21.6 g of BA, and 1.68 g of ALMA was added all at once. Completed.

  Next, 3.48 g of APS was added, and after stirring for 5 minutes, a monomer mixture consisting of BA 8105 g, PEGDA (200) 31.9 g, and ALMA 264.0 g was continuously added over 120 minutes. Hold for a minute to complete the soft layer polymerization.

  Next, 1.32 g of APS was added, and after stirring for 5 minutes, a monomer mixture consisting of 2106 g of MMA and 201.6 g of BA was continuously added over 20 minutes. The polymerization of was completed.

  Next, 1.32 g of APS was added, and after 5 minutes, a monomer mixture consisting of 3148 g of MMA, 201.6 g of BA, and 10.1 g of n-OM was continuously added over 20 minutes. Next, the temperature was raised to 95 ° C. and held for 60 minutes to complete the polymerization of the outermost hard layer 2.

  A small amount of the polymer latex thus obtained was collected, and the average particle size was determined by the absorbance method. As a result, it was 0.10 μm and 100 nm. The remaining latex was put into a 3% by mass sodium sulfate warm aqueous solution, salted out and coagulated, and then dried after repeated dehydration and washing to obtain acrylic particles (C1) having a three-layer structure.

  The above abbreviations are the following materials.

MMA; methyl methacrylate MA; methyl acrylate BA; n-butyl acrylate ALMA; allyl methacrylate PEGDA; polyethylene glycol diacrylate (molecular weight 200)
n-OM; n-octyl mercaptan APS; ammonium persulfate (UV absorber (D))
(Synthesis of Exemplified Compound 2)
2 g of Compound A was suspended in 10 ml of toluene, 0.1 ml of DMF and 1.14 g of thionyl chloride were added, and the mixture was heated to 60 ° C. and stirred for 30 minutes. As the reaction progressed, it began to dissolve and became a homogeneous solution after the reaction was completed. The solvent of the reaction mixture was removed under reduced pressure.

  80 ml of acetonitrile was added to the residue and suspended. In a separate container, 0.34 g of diethylene glycol and 0.76 g of pyridine were dissolved in acetonitrile, heated to 75 ° C. and stirred.

  The previous acetonitrile suspension was quickly added to it and stirred for 2 hours while maintaining 75 ° C. After completion of the reaction, the reaction mixture was cooled and then acetonitrile was removed under reduced pressure, followed by extraction with ethyl acetate and water.

  The organic layer was removed under reduced pressure, the residue was purified by silica gel column chromatography, and recrystallized from ethyl acetate to obtain 0.4 g (yield 18%) of Exemplary Compound 2. The structure was confirmed by NMR and Mass spectrum.

  1H-NMR (d-DMSO): σ 1.28 (s, 18H); 3.92 (m, 4H); 4.51 (m, 4H); 7.09 (d, J = 8.8 Hz, 2H) 7.49 (dd, J = 2.4 Hz, 8.5 Hz, 2H); 7.71 (d, J = 2.4 Hz, 2H); 7.93 (d, J = 8.8 Hz, 2H); 7.9 (d, J = 8.8 Hz, 2H); 8.60 (s, 2H); 10.2 (s, 2H)

(Synthesis of UV-absorbing polymer A)
Add 0.02 g of antimony oxide to 11.83 g (20 mmol) of dihydroxybenzotriazole (a) and 2.92 g (20 mmol) of adipic acid (b), and place in a polymerization tube equipped with a vacuum stirrer. A nitrogen gas introduction tube was connected to the polymerization tube, and this polymerization tube was put in an oil bath and slowly passed with nitrogen gas while being heated to 180 ° C. While stirring, the temperature was gradually raised to 270 ° C., and at the same time the degree of vacuum was increased to 102 Pa. After heating for 3 hours as it was, it was allowed to cool and polymer A was obtained quantitatively. As a result of measuring the molecular weight of the polymer A by GPC, the number average molecular weight was 12,500. The structure of the polymer was confirmed by 1H-NMR.

<Preparation of optical film 1>
(Dope solution composition 1)
Acrylic resin (A)
Dianar BR85 (Mitsubishi Rayon Co., Ltd.) 70 parts by weight Cellulose ester resin (B)
Cellulose acetate propionate Total acyl group substitution degree 2.75, acetyl group substitution degree 0.19, propionyl group substitution degree 2.56, Mw = 200000
30 parts by mass Acrylic particles Acrylic particles (C1) 5 parts by mass Ultraviolet absorber (D): Exemplified compound 2 2 parts by mass Methylene chloride 300 parts by mass Ethanol 40 parts by mass The above composition is sufficiently dissolved while heating, and a dope solution Was made.

(Formation of acrylic resin film 1)
The produced dope solution was uniformly cast on a stainless steel band support at a temperature of 22 ° C. and a width of 2 m using a belt casting apparatus. With the stainless steel band support, the solvent was evaporated until the amount of residual solvent reached 100%, and peeling was performed from the stainless steel band support with a peeling tension of 162 N / m.

  The peeled acrylic resin web was evaporated at 35 ° C., slit to 1.6 m width, and then dried at a drying temperature of 135 ° C. while being stretched 1.1 times in the width direction by a tenter. At this time, the residual solvent amount when starting stretching with a tenter was 10%.

  After stretching with a tenter and relaxing at 130 ° C for 5 minutes, drying was completed while transporting the drying zone at 120 ° C and 140 ° C with a number of rolls, slitting to a width of 1.5 m, and 10 mm wide at both ends of the film. A knurling process having a thickness of 5 μm was performed, and the film was wound around a core having an inner diameter of 6 inches with an initial tension of 220 N / m and a final tension of 110 N / m.

  The draw ratio in the MD direction calculated from the rotational speed of the stainless steel band support and the operating speed of the tenter was 1.1 times.

  The residual solvent amount of the optical film 1 described in Tables 1 to 4 was 0.1%, the film thickness was 60 μm, and the winding length was 4000 m.

  Hereinafter, except having changed the kind and composition ratio of an acrylic resin (A), a cellulose-ester resin (B), and an ultraviolet absorber (D) as described in Tables 1 to 4, the same as the optical film 1, Optical films 2 to 71 were produced.

  In the acyl group of the cellulose ester resin, pr represents a propionyl group and bu represents a butyryl group.

In Tables 1 to 4, the UV absorber (D) Tinuvin 109 and Tinuvin 171 are
Tinuvin 109 (Ciba Japan Co., Ltd.) 1.5 parts by mass Tinuvin 171 (Ciba Japan Co., Ltd.) 0.5 parts by mass was mixed and used.

(Adjustment of hard coat layer coating solution)
The following materials were stirred and mixed to obtain a hard coat layer coating solution.

Acrylic monomer; KAYARAD DPHA (dipentaerythritol hexaacrylate) (manufactured by Nippon Kayaku) 323 parts by mass Initiator; Irgacure 184 (manufactured by Ciba Japan Co., Ltd.) 36 parts by mass Leveling agent; Glycol monomethyl ether solution 7 parts by mass Propylene glycol monomethyl ether 317 parts by mass Ethyl acetate 317 parts by mass (Lamination of hard coat layer)
The said hard-coat layer coating liquid was apply | coated on the optical films 1-71 with the wire bar, and it dried for 30 second at 80 degreeC.

After drying, UV irradiation was performed (the output of the UV lamp was adjusted so as to be 120 mJ / cm ² ), and a hard coat layer having a thickness of 10 μm after curing was obtained.

"Evaluation method"
UV absorption performance Using Spectrophotometer U-3200 (manufactured by Hitachi, Ltd.), the spectral absorption spectrum of the film sample was measured, the transmittances at 400 nm and 380 nm were determined, and ranking was performed as follows. In each rank, the higher the transmittance at 400 nm, the better, and the lower the transmittance at 380 nm, the better.

<400 nm transmittance>
A: Transmittance 80% or more B: Transmittance 70% or more and less than 80% C: Transmittance 60% or more and less than 70% D: Transmittance less than 60% <380 nm transmittance>
A: Transmittance less than 5% B: Transmittance 5% or more and less than 8% C: Transmittance 8% or more and less than 10% D: Transmittance 10% or more Bleed-out After leaving in an atmosphere for 1000 hours, the presence or absence of bleed-out (crystal precipitation) on the surface of the film sample was visually observed and evaluated according to the criteria described below.

◎: No bleed-out is observed on the surface. ○: Partial bleed-out is slightly observed on the surface. △: Slight bleed-out is observed on the entire surface. A clear bleed-out is observed. Adhesion of the hard coat layer Using the cutter on the side where the resin layer of the above sample is provided, 11 scratches each having a width of 1 mm are prepared to make 100 squares of 1 mm square (cross cut). ) A tape (Cellophane tape No. 29 made by Nitto Denko) is applied on it, and after 10 rubbing with a spatula, the tape is peeled off vigorously. This operation was repeated three times to see the degree of film peeling.

◎: No film peeling ○: There is a very small amount of peeling △: There is a small amount of peeling ×: There is a large amount of peeling Haze For each of the film samples prepared above, humidity was adjusted in an air-conditioned room at 23 ° C. and 55% RH for 24 hours. After that, under the same conditions, one film sample was measured according to JIS K-7136 using a haze meter (NDH2000 type, manufactured by Nippon Denshoku Industries Co., Ltd.).

  The results of the above evaluation are shown in Tables 5 and 6.

  As described above, the optical film of the present invention is transparent and excellent in visible light transmission, has a high ultraviolet shielding effect, has no bleed out even when left under high temperature and high humidity, and has excellent durability. Indicated.

  Moreover, when the hard-coat layer is provided in the optical film of this invention, it is excellent also in adhesiveness.

Schematic diagram showing the dope preparation process, casting process and drying process of the solution casting film forming method

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Melting pot 3, 6, 12, 15 Filter 4, 13 Stock tank 5, 14 Liquid feed pump 8, 16 Conduit 10 Ultraviolet absorber charging pot 20 Merge pipe 21 Mixer 30 Die 31 Metal support 32 Web 33 Peeling position 34 Tenter device 35 Roll dryer 41 Particle charging vessel 42 Stock tank 43 Pump 44 Filter

Claims (12)

An acrylic resin and a cellulose ester resin are contained in a compatible state at a mass ratio of 70:30 to 30:70, the weight average molecular weight (Mw) of the acrylic resin is 80000 or more, and the acyl group of the cellulose ester resin The total substitution degree is 2.0 to 3.0, the substitution degree of the acyl group having 3 to 7 carbon atoms is 1.2 to 3.0, and the weight average molecular weight Mw of the cellulose ester resin is 75000 or more. An optical film characterized by comprising an ultraviolet absorber.   The optical film according to claim 1, further comprising an ultraviolet absorbing polymer as the ultraviolet absorber. The optical film according to claim 1, comprising at least one compound selected from compounds represented by the following general formulas (UVA1) to (UVA3) as the ultraviolet absorber.

(In General Formulas (UVA1) to (UVA3), R ₁ and R ₂ each represent a substituent, and X represents —COO—, —OCO—, —NR ₁₁ CO—, —CONR ₁₁ —, —O—. _{, -NR 12 R 13 -, -} SO 2 NR 14 -, - NR 14 SO 2 -, - S-, or -SO ₂ - represents, _{L 1} is a divalent linking group, _{L 2} is connected trivalent Group L ₃ represents a tetravalent linking group, R ₁₁ , R ₁₂ , R ₁₃ and R ₁₄ each represents a hydrogen atom, an alkyl group or an aryl group, p is an integer of 0 to 3, q is Represents an integer of 0 to 4)   4. The optical film according to claim 1, wherein the cellulose ester resin has a total substitution degree of acyl groups other than those having 3 to 7 carbon atoms of 1.3 or less.   5. The optical film according to claim 1, wherein the cellulose ester resin has a total substitution degree of acyl groups having 3 to 7 carbon atoms of 2.00 or more.   The total substitution degree of the acyl group of the said cellulose ester resin is 2.5-3.0, The optical film as described in any one of Claims 1-5 characterized by the above-mentioned.   The optical film according to any one of claims 1 to 6, wherein the acrylic resin is an acrylic resin having 50 to 99 mass% of methyl methacrylate units in the molecule. The optical film according to any one of claims 1 to 7, wherein a mass ratio of the acrylic resin and the cellulose ester resin is within a range of 70:30 to 50:50.   The weight average molecular weight (Mw) of the said acrylic resin exists in the range of 80000-1 million, The optical film as described in any one of Claims 1-8 characterized by the above-mentioned.   The weight average molecular weight (Mw) of the said cellulose ester resin exists in the range of 75000-300000, The optical film as described in any one of Claims 1-9 characterized by the above-mentioned.   The said optical film contains 0.5-30 mass% acrylic particle with respect to the gross mass of resin which comprises the said optical film, It is any one of Claims 1-10 characterized by the above-mentioned. Optical film.   11. The optical film according to claim 1, wherein the optical film has a thickness of 20 to 200 μm and is used as a polarizing plate protective film.

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