JP6257977B2 - Resin composition for polarizing plate and polarizing plate comprising the same - Google Patents

Description

  The present invention relates to a polarizing plate resin composition and a polarizing plate comprising the same.

A polarizing plate is usually a retardation film (reverse wavelength dispersion film) (film thickness of about 30 to 120 μm) on one or both sides of a polarizing film (film thickness of about 30 to 120 μm) made of a polyvinyl alcohol resin adsorbed and oriented with a dichroic dye. ), And a protective film (film thickness of about 30 to 120 μm) is laminated. The polarizing film is produced by a method in which a polyvinyl alcohol resin film is subjected to longitudinal uniaxial stretching and dyeing with a dichroic dye, followed by crosslinking with boric acid, followed by washing with water and drying. As the dichroic dye, iodine or a dichroic organic dye is used. A polarizing film is formed by laminating a retardation film and a protective film on one side or both sides of the polarizing film thus obtained, and is used by being incorporated in a liquid crystal display device. For the protective film, a cellulose acylate resin film typified by triacetyl cellulose is often used. In addition, an adhesive (film thickness of about 5 μm) made of an aqueous solution of polyvinyl alcohol resin is often used for laminating each film.
When the retardation film and the protective film are bonded to both sides of the polarizing film, the thickness becomes 620 μm at the maximum as the polarizing plate, and the distortion when heated is increased. For this reason, in a touch panel or the like, the front glass plate to be bonded to the polarizing plate is also formed into a thick film to prevent distortion when heated, but the entire touch panel becomes a considerably thick film.

  On the other hand, the need for thinning and lightening the touch panel is very strong. As an example of a method for producing a thin polarizing plate, after applying a solution containing a polyvinyl alcohol resin on the surface of the base film and providing a resin layer, A method is proposed in which a laminated film composed of a base film and a resin layer is stretched, then dyed, crosslinked, dried, and a polarizer layer is formed from the resin layer to obtain a polarizing laminated film having a polarizer layer. (For example, Patent Document 1). However, there is a limit to reducing the thickness of the polarizing plate, and the contribution to making the touch panel thinner and lighter is small. Further, the retardation film and the polarizing film have a low surface hardness, and a protective film is essential.

JP 2000-338329 A

  An object of the present invention is a novel resin composition for a polarizing plate, which is excellent in transparency, polarization and reverse wavelength dispersion, and further has excellent surface hardness and positive birefringence, and enables the thinning of a polarizing plate. Is to provide.

  The inventor of the present invention has arrived at the present invention as a result of intensive studies to achieve the above object. That is, in the present invention, at least one of the functional groups of at least one polysaccharide selected from the group consisting of hydroxyl group, carboxyl group and amino group is selected from the group consisting of urethane group, urea group, amide group and imide group. It is the resin composition for polarizing plates containing the modified polysaccharide (A) and polyvinyl alcohol (B) which are chemically modified by at least 1 type of functional group.

  Moreover, this invention is a polarizing plate formed from the said resin composition for polarizing plates.

The resin composition for polarizing plates of the present invention has the following effects.
(1) A polarizing plate formed from the resin composition for a polarizing plate of the present invention is excellent in transparency, polarization and reverse wavelength dispersion, and further excellent in surface hardness and positive birefringence. Is possible.

  In the polarizing plate resin composition of the present invention, at least one of the functional groups of at least one polysaccharide selected from the group consisting of a hydroxyl group, a carboxyl group, and an amino group is a urethane group, a urea group, an amide group, and an imide group. It is the resin composition for polarizing plates containing the modified polysaccharide (A) and polyvinyl alcohol (B) which are chemically modified by the at least 1 sort (s) of functional group chosen from the group which consists of.

  The resin obtained from the resin composition for polarizing plates of the present invention is excellent in transparency, polarization and reverse wavelength dispersion. Furthermore, since the surface hardness is high and the positive birefringence is excellent, if a polarizing plate is prepared by molding the polarizing plate resin composition of the present invention, it is not necessary to laminate a surface protective film or a retardation film. Therefore, the polarizing plate can be made thin.

The polysaccharide includes conventionally known polysaccharides and can be used without any particular limitation. Specifically, the following polysaccharide (a) is included.
Examples of the polysaccharide (a) include starch (including amylose and amylopectin), glycogen, cellulose, chitin, chitosan, agarose, carrageenan, heparin, hyaluronic acid, pectin, xyloglucan, xanthan gum, and functional groups having urethane groups, ureas. At least one polysaccharide selected from the group consisting of substituted polysaccharides other than groups, amide groups and imide groups is included.
As a polysaccharide, 1 type may be used independently and 2 or more types may be used together.

  The substituted polysaccharide includes known substituted polysaccharides. The substituted polysaccharide is preferably a substituted known cellulose from the viewpoints of birefringence, reverse wavelength dispersion and water resistance. As the substituted known cellulose, acylated cellulose (a1), etherified cellulose (a2) and etherified acylated cellulose (a3) are included.

Examples of the acylated cellulose (a1) include acylated cellulose substituted with an acyl group having 2 to 19 carbon atoms, which may be partially substituted with a hydroxyl group. For example, reaction between cellulose and carboxylic acid or lactone Things.
Examples of carboxylic acids include those having 2 to 19 carbon atoms, such as acetic acid, butyric acid, 2-ethylhexanoic acid, n-octylic acid, neodecanoic acid, dodecanoic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid. Benzoic acid and phthalic acid. The carboxylic acid may be an acid halide such as acid chloride {as halogen, for example, F, Cl, Br, etc.}. Moreover, these may use 1 type and may use 2 or more types.
Lactones include those having 2 to 19 carbon atoms, such as β-lactone (β-propiolactone, etc.), γ-lactone (γ-butyrolactone, etc.), δ-lactone (δ-valerolactone, etc.), ε- Examples include lactones (such as ε-caprolactone), macrocyclic lactones (such as enanthlactone, undecanolactone, dodecalactone), and aromatic lactones (3,4-dihydrocoumarin). These may use 1 type and may use 2 or more types.
Examples of the acyl group having 2 to 19 carbon atoms which may be partially substituted with a hydroxyl group include, for example, an acetyl group, a propionyl group, a butyryl group, a valeryl group, a benzoyl group, a 6-hydroxyhexanoyl group (HO—C ₅ H ₁₀ -CO-) and 3- (2-hydroxyphenyl) propionyl group.
As the acyl group, from the viewpoint of water resistance, transparency, saponification resistance, positive birefringence and reverse wavelength dispersion, an acyl group having 2 to 19 carbon atoms which may be partially substituted with a hydroxyl group is used. Preferably, more preferably an acyl group having 2 to 10 carbon atoms which may be partially substituted with a hydroxyl group, particularly preferably an acetyl group, a propionyl group, a butyryl group, a valeryl group, a benzoyl group, a 6-hydroxyhexanoyl group It is at least one selected from the group consisting of (HO—C ₅ H ₁₀ —CO—) and 3- (2-hydroxyphenyl) propionyl group.
Specific examples of (a1) include acetyl cellulose, diacetyl cellulose, triacetyl cellulose, acetyl butyryl cellulose, acetyl propionyl cellulose, and acetyl 3- (2-hydroxyphenyl) propionyl cellulose.
Among (a1), from the viewpoints of water resistance, transparency, saponification resistance, positive birefringence and reverse wavelength dispersion, an acyl group having 2 to 19 carbon atoms which may be partially substituted with a hydroxyl group And more preferably an acetyl group, a propionyl group, a butyryl group, a valeryl group, a benzoyl group, a 6-hydroxyhexanoyl group (HO—C ₅ H ₁₀ —CO—) and 3- (2 -Hydroxyphenyl) acylated cellulose having at least one functional group selected from the group consisting of propionyl groups, and more preferably at least one function selected from the group consisting of acetyl group, propionyl group and butyryl group Acylated cellulose having a group, particularly preferably diacetylcellulose, acetylpropionylcellulose and acetyl Butyryl cellulose, most preferably diacetyl cellulose.

The etherified cellulose (a2) includes etherified cellulose substituted with an alkyl ether group having 1 to 18 carbon atoms, which may be partially substituted with a hydroxyl group or a carboxyl group.
Examples of the alkyl ether group include alkyl ether groups having 1 to 18 carbon atoms which may be partially substituted with a hydroxyl group or a carboxyl group, such as a methoxy group, an ethoxy group, a propoxy group, a hydroxymethoxyl group, Those having at least one functional group selected from the group consisting of hydroxyethoxyl group, 1-phenylethoxy group, 2-phenylethoxy group and carboxymethoxyl group are included.
As the alkyl ether group, from the viewpoints of water resistance, transparency, saponification resistance, positive birefringence and reverse wavelength dispersion, the alkyl which may be partially substituted with a hydroxyl group or a carboxyl group has 1 carbon atom. Is preferably an alkyl ether group having 1 to 8 carbon atoms, which may be partially substituted with a hydroxyl group or a carboxyl group, and particularly preferably a methoxy group, an ethoxy group, or a propoxy group. And at least one functional group selected from the group consisting of a group, a hydroxymethoxyl group, a 1-phenylethoxy group, a 2-phenylethoxy group, a hydroxyethoxyl group, and a carboxymethoxy group.
Specific examples of (a2) include methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl methyl cellulose, 1-phenylethyl cellulose, 2-phenylethyl cellulose, and carboxymethyl cellulose.
Among (a2), from the viewpoints of water resistance, transparency, saponification resistance, positive birefringence and reverse wavelength dispersion, the number of carbon atoms of the alkyl which may be partially substituted with a hydroxyl group or a carboxyl group is 1 Etherified cellulose substituted with ˜18 alkyl ether groups is preferred, and more preferably, alkyl which may be partially substituted with a hydroxyl group or a carboxyl group is substituted with an alkyl ether group having 1 to 3 carbon atoms. Etherified cellulose, particularly preferably carboxymethylcellulose, methylcellulose, ethylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxyethylmethylcellulose and hydroxypropylmethylcellulose, more particularly methylcellulose, ethyl Cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxy methyl cellulose and hydroxyethyl cellulose, and most preferably cellulose and hydroxyethyl cellulose.

The etherified acylated cellulose (a3) has an alkyl ether group having 1 to 18 carbon atoms which may be partially substituted with a hydroxyl group or a carboxyl group, and a carbon number which may be partially substituted with a hydroxyl group. Examples include cellulose having 2 to 19 acyl groups, and specific examples include hydroxypropylmethylcellulose hexahydrophthalate, hydroxypropylmethylcellulose acetate phthalate, and hydroxypropylmethylcellulose acetate succinate.
The preferred ether group and acyl group are the same as those in (a1) and (a2).
Among (a3), from the viewpoints of water resistance, transparency, saponification resistance, positive birefringence and reverse wavelength dispersion, hydroxypropylmethylcellulose phthalate, hydroxypropylmethylcellulose hexahydrophthalate and hydroxypropylmethylcellulose acetate succinate are preferable.

  Among the polysaccharides, from the viewpoint of transparency, saponification resistance, positive birefringence and reverse wavelength dispersion, the polysaccharide (a) is preferred, more preferably cellulose and substituted cellulose, and still more preferably cellulose. Acylated cellulose (a1), etherified cellulose (a2), and etherified acylated cellulose (a3), particularly preferably cellulose, acylated cellulose (a1), and etherified cellulose (a2), and particularly preferably Is cellulose, acetylcellulose, methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose and hydroxyethylmethylcellulose, most preferably hydroxycellulose methylcellulose.

In the modified polysaccharide (A) in the present invention, at least one of the functional groups of at least one polysaccharide selected from the group consisting of a hydroxyl group, a carboxyl group and an amino group is a urethane group, a urea group, an amide group and an imide group. A modified polysaccharide that is chemically modified with at least one functional group selected from the group consisting of:
The modified polysaccharide (A) preferably has no (meth) acryloyl group from the viewpoint of reverse wavelength dispersion.
The modified polysaccharide (A) is a total introduction of a urethane group, a urea group, an amide group and an imide group determined by the following formula (1) from the viewpoints of transparency, polarization, positive birefringence and reverse wavelength dispersion. It is preferably a modified polysaccharide with a rate of 0.01 to 3, more preferably 0.04 to 3, then more preferably 0.06 to 3, particularly preferably 0.11 to 3. is there.
Total introduction rate of urethane group, urea group, amide group and imide group = R / T ′ (1)
R: NMR integral value (R ₁ ) of hydrogen atom of urethane group substituted with hydroxyl group, carboxyl group and amino group of monosaccharide unit constituting modified polysaccharide (A), NMR integral of hydrogen atom of urea group The total integrated value R = obtained by applying the value (R ₂ ), the NMR integrated value (R ₃ ) of the hydrogen atom of the amide group, and the NMR integrated value (R ₄ ) of the hydrogen atom of the imide group to the following formula (2) _{R 1 + R 2/2 +} R 3 + R 4
Instead an amide group {-CO-NH-R (R is other than a hydrogen atom)}, (- CO-NH 2) if it is, the R ₃ and R _3/2.
T ′: NMR integral value of a hydrogen atom directly bonded to the 4-position carbon atom of the monosaccharide unit constituting the modified polysaccharide (A) <the total introduction rate of urethane group, urea group, amide group and imide group Measuring method>
Solvent: Deuterated dimethyl sulfoxide Device: AVANCE300 (manufactured by Nippon Bruker Co., Ltd.)
Frequency: 300MHz
When the introduction ratio is larger than 0.01, the transparency and the reverse wavelength dispersion are further improved, and when the introduction ratio is 3 or less, the positive birefringence is further improved.

  As the modified polysaccharide (A) in the present invention, at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group and an amino group of the monosaccharide unit constituting the modified polysaccharide is an isocyanate compound. Those chemically modified with at least one compound selected from the group consisting of (y1), amino compound (y2), acid halogen compound (y3) and acid anhydride (y4) are included.

The isocyanate compound (y1) includes a polyisocyanate compound (y11) having two or more isocyanate groups in one compound molecule and a monoisocyanate compound (y12) having one isocyanate group in one compound molecule.
(Y11) includes organic polyisocyanates generally used for the production of urethane resins. For example, aromatic polyisocyanates, chain aliphatic polyisocyanates, alicyclic polyisocyanates, araliphatic polyisocyanates, and modified products thereof. (Urethane group, carbodiimide group, allophanate group, urea group, burette group, isocyanurate group and oxazolidone group-containing modified product). (Y11) may be used alone or in combination of two or more.

  Aromatic polyisocyanates include aromatic diisocyanates having 6 to 16 carbon atoms (excluding carbons in NCO groups; the following polyisocyanates are also the same), aromatic triisocyanates having 6 to 20 carbon atoms, and crude products of these isocyanates. Thing etc. are mentioned. Specific examples include 1,3- or 1,4-phenylene diisocyanate, 2,4- or 2,6-tolylene diisocyanate (TDI), crude TDI, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane. Examples include diisocyanate (MDI), polymethylene polyphenylene polyisocyanate (crude MDI), naphthylene-1,5-diisocyanate, and triphenylmethane-4,4 ′, 4 ″ -triisocyanate.

  Examples of the chain aliphatic polyisocyanate include chain aliphatic diisocyanates having 1 to 10 carbon atoms (1,6-hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, etc.). Can be mentioned.

  Examples of the alicyclic polyisocyanates include alicyclic diisocyanates having 6 to 16 carbon atoms (isophorone diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, norbornane diisocyanate and bis (2-isocyanatoethyl)- 4-cyclohexene-1,2-dicarboxylate and the like.

  Examples of the araliphatic polyisocyanate include araliphatic diisocyanates having 8 to 12 carbon atoms (such as xylylene diisocyanate and α, α, α ′, α′-tetramethylxylylene diisocyanate).

  Specific examples of the modified polyisocyanate include carbodiimide-modified MDI.

  Of (y11), chain aliphatic polyisocyanates are preferred from the viewpoints of saponification resistance, transparency, positive birefringence, and reverse wavelength dispersion.

When the modified polysaccharide (A) is prepared using (y11), a compound (z) having at least one active hydrogen group may be used.
(Z) includes a compound having at least one active hydrogen group having 4 to 100 carbon atoms.
Examples of the active hydrogen group include a hydroxyl group, an amino group, a carboxyl group, a thiol group, and a phosphate group.
As (z), specifically, those having a hydroxyl group {methanol, ethanol, n-propanol, n-butanol, n-octanol, phenol, etc.}, those having an amino group {ethylamine etc.}, having a carboxyl group Things {formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, lauric acid, myristic acid, stearic acid, behenic acid, etc.}, those having a thiol group {octane Thiol and the like} and those having a phosphoric acid group {reaction products of the above-mentioned hydroxyl group (such as methanol) and phosphoric anhydride} and the like.
(Z) may be used alone or in combination of two or more.
Among (z), from the viewpoint of surface hardness, resin strength, elongation at break, flexibility and positive birefringence, a compound having a hydroxyl group having 4 to 100 carbon atoms is preferable, and more preferably 4 to 10 carbon atoms. It is a compound having a hydroxyl group.

Examples of (y12) include aromatic monoisocyanates, alkyl monoisocyanates, alicyclic monoisocyanates, and reaction products having a molar ratio of 1: 1 between a diisocyanate compound and a compound having one active hydrogen group.
The aromatic monoisocyanate includes aromatic monoisocyanates having 6 to 20 carbon atoms (excluding carbon in the NCO group, the same shall apply hereinafter), specifically phenyl isocyanate, tolylene isocyanate, xylylene isocyanate, α, α, α ′, α′-tetramethylxylylene isocyanate, naphthylene isocyanate and the like can be mentioned.
Examples of the alkyl monoisocyanate include alkyl (straight or branched) monoisocyanates having 1 to 100 carbon atoms, specifically those having 1 to 18 carbon atoms {methyl isocyanate, ethyl isocyanate, n-propyl isocyanate, n -Butyl isocyanate, sec-butyl isocyanate, t-butyl isocyanate, n-hexyl isocyanate, 2-ethylhexyl isocyanate, n-octyl isocyanate, n-dodecyl isocyanate, n-stearyl isocyanate, etc.}. As the alkyl monoisocyanate, those having 1 to 18 carbon atoms are preferable from the viewpoints of transparency, saponification resistance, positive birefringence and reverse wavelength dispersion.
Examples of the alicyclic monoisocyanate include alicyclic monoisocyanates having 4 to 15 carbon atoms, and specifically include cyclobutyl isocyanate, cyclohexyl isocyanate, cyclooctyl isocyanate, cyclodecyl isocyanate, cyclododecyl isocyanate, and cyclotetradecyl. Examples include isocyanate, cyclotetradecyl isocyanate, isophorone isocyanate, dicyclohexylmethane-4-isocyanate, cyclohexyl isocyanate, methylcyclohexyl isocyanate, and norbornane isocyanate.

In the reaction product having a molar ratio of 1: 1 between the diisocyanate compound and the compound having one active hydrogen group, the diisocyanate compound includes a diisocyanate compound having two isocyanate groups in the above (y11), specifically, , Aromatic diisocyanate {1,3- or 1,4-phenylene diisocyanate, 2,4- or 2,6-tolylene diisocyanate (TDI), crude TDI, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane Diisocyanate (MDI) and naphthylene-1,5-diisocyanate, etc.}, alkyl (linear or branched) diisocyanate {1,6-hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, etc.}, alicyclic ring Formula Socynate {isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate and norbornane diisocyanate etc.} and araliphatic diisocyanates {xylylene diisocyanate and α, α, α ', α'-tetramethylxylylene diisocyanate Etc.}.
Moreover, as a compound which has one active hydrogen group, what has one active hydrogen group etc. is mentioned among the said compounds (z), Specifically, C1-C100 monoalcohol {methanol, Ethanol, n-propanol, n-butanol, n-octanol, phenol, etc., preferably from the viewpoint of surface hardness, resin strength, elongation at break, flexibility and positive birefringence} C1-C100 monoamine {ethylamine etc.], C1-C100 monovalent carboxylic acid {formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid , Lauric acid, myristic acid, stearic acid, behenic acid and the like}.

  Of (y12), from the viewpoints of saponification resistance, transparency, surface hardness, resin strength, elongation at break, flexibility and positive birefringence, alkyl monoisocyanates and alicyclic monoisocyanates are preferred, and more preferred. Are alkyl monoisocyanates having 1 to 18 carbon atoms and alicyclic monoisocyanates having 4 to 15 carbon atoms, particularly preferably methyl isocyanate, ethyl isocyanate, n-propyl isocyanate, n-butyl isocyanate, sec-butyl. Isocyanate, t-butyl isocyanate, n-hexyl isocyanate, cyclohexyl isocyanate, 2-ethylhexyl isocyanate, n-octyl isocyanate, n-dodecyl isocyanate and n-stearyl isocyanate.

(Y1) may be used alone or in combination of two or more.
Among (y1), from the viewpoint of saponification resistance, transparency, surface hardness, resin strength, elongation at break, flexibility and positive birefringence, the monoisocyanate compound (y12) is preferable, and more preferably alkylmono An isocyanate and an alicyclic monoisocyanate, and more preferably an alkyl monoisocyanate having 1 to 18 carbon atoms and an alicyclic monoisocyanate having 4 to 15 carbon atoms, particularly preferably methyl isocyanate, ethyl isocyanate, n-propyl isocyanate, n-butyl isocyanate, sec-butyl isocyanate, t-butyl isocyanate, n-hexyl isocyanate, cyclohexyl isocyanate, 2-ethylhexyl isocyanate, n-octyl isocyanate, n-dodecyl isocyanate And a n- stearyl isocyanate, most preferably methyl isocyanate, ethyl isocyanate, n- butyl isocyanate and stearyl isocyanate.

Amino compounds (y2) include ammonia, primary amines and secondary amines.
Primary amines include monoamines having 1 to 20 carbon atoms {alkyl (linear or branched) monoamines, alicyclic monoamines, araliphatic monoamines, aromatic monoamines and alkanolamines} and polyamines having 1 to 20 carbon atoms { Diamine, triamine and the like}.
Examples of monoamines include alkyl monoamines {monoalkyl (alkyl having 1 to 20 carbon atoms) amine (such as methylamine, ethylamine, n-butylamine and octylamine)}, alicyclic monoamines {such as cyclohexylamine}, Araliphatic amines {such as benzylamine}, aromatic amines {such as aniline, toluidine and naphthylamine) and alkanolamines {including monoalkanolamines (hydroxyalkyl groups having 1 to 20 carbon atoms such as ethanolamine) Etc.) etc.}.

The secondary amine includes amines having a hydrocarbon group having 1 to 20 carbon atoms and / or a hydroxyalkyl group having 1 to 20 carbon atoms.
Hydrocarbon groups include alkyl groups (straight or branched) (such as methyl, ethyl and propyl groups), alicyclic groups (such as cyclohexyl groups), and aromatic hydrocarbons (such as phenyl and naphthyl groups). Etc.
Specific examples of the secondary amine include dimethylamine, diethylamine, ethylmethylamine, and diethanolamine.

(Y2) may be used alone or in combination of two or more.
Of (y2), alkyl monoamines and alicyclic monoamines are preferable from the viewpoints of saponification resistance, transparency, surface hardness, resin strength, elongation at break, flexibility, and positive birefringence.

Examples of the acid halogen compound (y3) include halides (acyl halides) of carboxylic acids having 1 to 20 carbon atoms, and specific examples of carboxylic acids include aliphatic monocarboxylic acids (formic acid having 1 to 20 carbon atoms). , Acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, lauric acid, myristic acid and stearic acid), C7-20 aromatic monocarboxylic acid (benzoic acid) Acid, cinnamic acid, naphthoic acid, etc.), C3-C20 aliphatic polycarboxylic acid (oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, etc. ) And aromatic polycarboxylic acids having 8 to 20 carbon atoms (phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, etc.) That.
Examples of the halide include fluoride, chloride, bromide and iodide.

(Y3) may be used alone or in combination of two or more.
Among (y3), from the viewpoint of saponification resistance, transparency, surface hardness, resin strength, elongation at break, flexibility and positive birefringence, an aliphatic monocarboxylic acid halide having 1 to 20 carbon atoms is used. preferable.

Examples of the acid anhydride (y4) include C3-C20 compounds having a 1,3-dioxo-2-oxaalkylene group, and dicarboxylic acids {aliphatic dicarboxylic acids (succinic acid, adipic acid, azelaic acid, Sebacic acid and maleic acid etc.) and aromatic dicarboxylic acids (phthalic acid etc.)} acid anhydrides and the like.
(Y4) may be used alone or in combination of two or more.
Among (y4), from the viewpoints of saponification resistance, transparency, surface hardness, resin strength, elongation at break, flexibility and positive birefringence, aliphatic dicarboxylic acid acid anhydrides are preferred.

  Of the above (y1) to (y4), (y1) is preferable from the viewpoints of transparency, polarization, positive birefringence, and reverse wavelength dispersion.

The modified polysaccharide (A) is at least one compound selected from the group consisting of the polysaccharide (a), an isocyanate compound (y1), an amino compound (y2), an acid halogen compound (y3), and an acid anhydride (y4). It can manufacture by using.
When the modified polysaccharide (A) is produced using the polysaccharide (a) and the isocyanate compound (y1), a compound having at least one selected from the group consisting of a hydroxyl group, a carboxyl group and an amino group and an isocyanate compound are used. A known method for reacting can be used.
Moreover, when manufacturing a modified polysaccharide (A) using a polysaccharide (a) and an amino compound (y2), using the well-known method of making the compound which has a carboxyl group, and an amino compound react, and obtaining an amide compound. Can do.
In the case of producing the modified polysaccharide (A) using the polysaccharide (a) and the acid halogen compound (y3), a known method for obtaining an imide compound by reacting a compound having an amino group with an acid halogen compound. Can be used.
Moreover, when manufacturing modified polysaccharide (A) using polysaccharide (a) and acid anhydride (y4), the compound which has an amino group, and acid anhydride are made to react, and an amide compound and / or an imide compound are made. Any known method can be used.

  Among the modified polysaccharides (A) having a urethane group, a urea group, an amide group and an imide group, the polysaccharide is the polysaccharide (a) from the viewpoint of transparency, positive birefringence and reverse wavelength dispersion, and the modification At least one of the monosaccharide units constituting the polysaccharide has at least one structure selected from the group consisting of the following general formulas (1) to (6), and has at least one substituent represented by the following general formula (7). The modified polysaccharide (A1) containing one is preferred.

In the above formula, X ^{1 to} X ¹³ are each independently a hydrogen atom or a substituent represented by the following general formula (7); at least one of X ^{1 to} X ³ is the following general formula (7) And at least one of X ^{4 to} X ⁶ is a substituent represented by the following general formula (7); at least one of X ⁷ and X ⁸ is represented by the following general formula ( 7); at least one of X ¹⁰ and X ¹¹ is a substituent represented by the following general formula (7); at least one of X ¹² and X ¹³ is the following general formula A substituent represented by formula (7); Y is an oxygen atom or NH group, and Z is a hydroxyl group or a substituent represented by (8).

In the above formula, R ¹ represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 18 carbon atoms; * represents a substituent represented by the general formula (7) by a bond to which R ¹ is attached; In the general formulas (1) to (6), it represents binding to X and an adjacent oxygen atom or nitrogen atom.

In the above formula, R ² represents a monovalent hydrocarbon group having 1 to 18 carbon atoms or an alkylpolyoxyalkylene group; * represents a substituent represented by the general formula (8) by a bond to which R ² is attached. Represents bonding to Z in the general formula (5) and an adjacent carbon atom.

Of the structures of the general formulas (1) to (6), from the viewpoint of surface hardness and flexibility, the general formula (1) or (6) is preferable, and the general formula (1) is more preferable. . In the general formulas (7) and (8), from the viewpoint of surface hardness, adhesion, and flexibility, preferred R ¹ and R ² are hydrocarbon groups having 1 to 18 carbon atoms, and particularly preferred R ¹ and R ^2. Are each independently a methyl group, an ethyl group, an n-propyl group, an n-butyl group, a sec-butyl group, a t-butyl group, an n-hexyl group, a 2-ethylhexyl group, an n-octyl group, or an n-dodecyl group. , N-stearyl group and phenyl group.

  The molecular weight (number average molecular weight (Mn) in the case of a single product) of the modified polysaccharide (A) is preferably 3000 to 7 million, more preferably from the viewpoint of the solvent solubility of (A) and the heat resistance of the polarizing plate. Is 3500 to 6.5 million, particularly preferably 4000 to 6.5 million, and most preferably 3.5 to 6.5 million.

The number average molecular weight (Mn) in the present invention is measured under the following conditions.
Apparatus: Gel permeation chromatography Solvent: N, N'-dimethylformamide Reference substance: Polystyrene Sample concentration: 3 mg / ml
Column stationary phase: PLgel MIXED-B
Column temperature: 40 ° C

  The content of the modified polysaccharide (A) is 0.1 to 99.8% by weight from the viewpoint of transparency, positive birefringence and reverse wavelength dispersion, based on the weight of the resin composition for polarizing plate. Preferably, it is 20 to 99% by weight.

  In the present invention, the polyvinyl alcohol (B) includes polyvinyl alcohol having a number average molecular weight (hereinafter abbreviated as Mn) of 1,000,000 to 1,000,000, and has polarizability, positive birefringence and reverse wavelength dispersion. From the viewpoint, Mn is preferably 1000 to 500,000. As the polyvinyl alcohol (B), for example, Kuraray Poval PVA (manufactured by Kuraray Co., Ltd.) {the branch numbers are 102 (Mn 9,000), 103 (Mn 13,500), 105 (Mn 22,500), 110 (Mn 45, 000), 117 (Mn 76,500), 120 (Mn 90,000), 124 (Mn 108,000), 613 (Mn 65,000), 617 (Mn 90,000), 624 (Mn 120,000), 706 (Mn 32,000) ), 203 (Mn 15,000), 205 (Mn 25,000), 210 (Mn 50,000), 217 (Mn 80,000), 220 (Mn 100,000), 224 (Mn 120,000), 235 (Mn 165,000) 403 (Mn 18,000), 405 (Mn 30,000) Those such as beauty 420 (Mn130,000)} and the like. (B) may be used individually by 1 type, and may use 2 or more types together.

  The content of the polyvinyl alcohol (B) is preferably from 0.1 to 98.9% by weight based on the weight of the polarizing plate resin composition, from the viewpoints of polarization, positive birefringence and reverse wavelength dispersion. More preferably, it is 0.1 to 90% by weight, and particularly preferably 1 to 80% by weight.

  The resin composition for polarizing plates of the present invention can contain esterified cellulose (C). Since the modified polysaccharide (A) has very high reverse wavelength dispersion, the reverse wavelength dispersion can be appropriately adjusted by containing (C) having low reverse wavelength dispersion.

  As esterified cellulose (C) in this invention, well-known esterified cellulose is contained, for example, alkyl esterified cellulose (C1-C18 of alkyl) etc. are mentioned, As alkyl ester group, it is acetate group, for example , Propionate group, butyrate group and the like. (C) may be used individually by 1 type, and may use 2 or more types together.

Esterification rate of esterified cellulose (C) (average number of hydroxyl groups directly bonded to cellulose per monosaccharide unit substituted with ester groups) is transparent, positive birefringence and reverse wavelength dispersion From this viewpoint, 0.1 to 3 is preferable.
The esterification rate of esterified cellulose is determined by NMR.

  Mn of the esterified cellulose (C) is preferably from 3 to 10 million, more preferably from 5 to 8 million, from the viewpoints of transparency, positive birefringence and reverse wavelength dispersibility.

  Among these (C), from the viewpoint of reverse wavelength dispersion, an alkylesterified cellulose having 1 to 18 carbon atoms is preferable, and more preferably at least one selected from the group consisting of an acetate group, a propionate group, and a butyrate group. Esterified cellulose having an ester group, and more preferably cellulose acetate, cellulose butyrate, cellulose propionate, cellulose acetate propionate, and cellulose acetate butyrate.

In the resin composition for polarizing plates of this invention, when esterified cellulose (C) is contained, content of the modified polysaccharide (A) in the resin composition for polarizing plates is transparency, positive birefringence, and From the viewpoint of reverse wavelength dispersion, the content is preferably 1 to 99.8% by weight, more preferably 20 to 98% by weight, based on the weight of the resin composition for polarizing plates.
In the resin composition for polarizing plates of the present invention, when the esterified cellulose (C) is contained, the content of the polyvinyl alcohol (B) is 0 from the viewpoints of polarization, positive birefringence, and reverse wavelength dispersion. 0.1-98.9% by weight is preferable, and 1-79% by weight is more preferable.
When the resin composition for polarizing plates of the present invention contains esterified cellulose (C), the content of esterified cellulose (C) in the resin composition for polarizing plates is the weight of the resin composition for polarizing plates. As a reference, from the viewpoint of transparency, positive birefringence and reverse wavelength dispersion, it is preferably 0.1 to 98.9% by weight, and more preferably 1 to 79% by weight.

  An organic solvent, a leveling agent, etc. can be added to the resin composition for polarizing plates of this invention as needed.

Examples of the organic solvent include glycol ether (ethylene glycol monoalkyl ether and propylene glycol monoalkyl ether), ketone (acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), ester (ethyl acetate, butyl acetate, ethylene glycol alkyl ether acetate, Methyl lactate and propylene glycol alkyl ether acetate, etc.), aromatic hydrocarbons (toluene, xylene, mesitylene, etc.), alcohols (methanol, ethanol, normal propanol, isopropanol, butanol, geraniol, linalool, citronellol, etc.), amides (N, N -Dimethylacetamide and N, N-dimethylformamide, etc.), sulfoxide (dimethylsulfoxy) ) And ether (tetrahydrofuran, 1,3-dioxane, 1,4-dioxane, 1,3-dioxolane and 1,8-cineole and the like) and the like. These may be used alone or in combination of two or more.
The addition amount of the organic solvent is preferably 0 to 400% by weight, more preferably 3 to 350% by weight, and particularly preferably 5 to 300% by weight with respect to the weight of the resin composition for polarizing plate, from the viewpoint of viscosity. %.

  Examples of the leveling agent include fluorine-based leveling agents (perfluoroalkylethylene oxide adducts and the like) and silicone-based leveling agents (amino polyether-modified silicone, methoxy-modified silicone, polyether-modified silicone, and the like). The addition amount of the leveling agent is preferably 0 to 20% by weight, more preferably 0.05 to 10% by weight, particularly preferably 0, from the viewpoint of the effect of addition and transparency with respect to the weight of the resin composition for polarizing plate. .1 to 5% by weight.

  The resin composition for a polarizing plate of the present invention further comprises inorganic fine particles, a dispersant, an antifoaming agent, a thixotropy imparting agent, a slip agent, a flame retardant, an antistatic agent, an antioxidant, and an ultraviolet absorber according to the purpose of use. Known additives that can be added to the polarizing plate composition, such as an agent, can be added. Specific examples include those described in publicly known documents (JP 2012-088408, etc.).

  The resin composition for polarizing plates of the present invention comprises a modified polysaccharide (A) having at least one selected from the group consisting of urethane groups, urea groups, amide groups and imide groups, and, if necessary, esterified cellulose (B). In addition, the organic solvent and other components can be obtained by mixing and stirring with a disperser or the like. The mixing and stirring temperature is usually 10 ° C to 40 ° C, preferably 20 ° C to 30 ° C.

  The resin composition for polarizing plates of this invention can add the pigment conventionally used for a coating material, ink, etc. The addition amount of the pigment is preferably 0 to 300% by weight, more preferably 0 to 200% by weight, from the viewpoint of concealment, with respect to the weight of the resin composition for polarizing plate.

  Examples of the pigment include yellow lead, zinc yellow, bitumen, barium sulfate, cadmium red, titanium oxide, zinc white, bengara, alumina, calcium carbonate, ultramarine blue, carbon black, graphite, and titanium black.

When using a pigment, the resin composition for polarizing plates of this invention can add a pigment dispersant, in order to improve the dispersibility and the storage stability of the resin composition for polarizing plates.
Examples of the pigment dispersant include pigment dispersants manufactured by Big Chemie (Anti-Terra-U, Disperbyk-101, 103, 106, 110, 161, 162, 164, 166, 167, 168, 170, 174, 182, 184 and 2020). Etc.), Ajinomoto Fine Techno Co., Ltd. pigment dispersants (Ajisper PB711, PB821, PB814, PN411, PA111, etc.), Lubrizol Corporation pigment dispersants (Solspers 5000, 12000, 32000, 33000, 39000, etc.). These pigment dispersants may be used alone or in combination of two or more. The addition amount of the pigment dispersant is preferably 0 to 20% by weight, more preferably 0 to 10% by weight with respect to the weight of the resin composition for polarizing plate from the viewpoint of concealment.

As a film forming method of the resin composition for polarizing plate of the present invention, a solution film forming method {solidification method, casting method (band method, drum method)}, melt film forming method {T die method (cast method, uniaxial stretching) Known film forming methods such as a method, a sequential secondary stretching method, a simultaneous secondary stretching method), a ring die method (an inflation method, a tube method)} and a calendar method, and combinations thereof can be applied.
The film thickness after film formation is preferably from 100 to 300 μm, more preferably from 10 to 250 μm, from the viewpoints of dryness, abrasion resistance, solvent resistance, and contamination resistance.
The draw ratio is preferably 1.1 to 5 times, more preferably 1.5 to 2.5 times from the viewpoint of reverse wavelength dispersibility.

  When the resin composition for polarizing plates of this invention contains the organic solvent, it is preferable to apply the solution film-forming method. Examples of the drying method include hot air drying (such as a dryer). The drying temperature is preferably 10 to 200 ° C. from the viewpoint of drying speed, coating film smoothness and appearance, and from the viewpoint of coating film smoothness and appearance, a more preferred upper limit is 150 ° C., from the viewpoint of drying speed, and further A preferred lower limit is 30 ° C.

In the present invention, the absolute value of the reflection chromaticity b * obtained in accordance with JIS-Z8729 of the film obtained by molding the resin composition for polarizing plates into a film thickness of 80 μm is 0 to 1.0, but is transparent. In view of the above, 0 to 0.5 is preferable, 0 to 0.25 is more preferable, and 0 to 0.2 is particularly preferable.
The absolute value of the reflection chromaticity b * is lowered by reducing the amount of aromatic isocyanate (aromatic polyisocyanate and aromatic monoisocyanate) used in the production of (A), and the amount of aromatic isocyanate used is increased. Will be higher. Moreover, in aromatic polyisocyanate and aromatic monoisocyanate, it is also possible to reduce the reflection chromaticity b * by introducing a hydrocarbon group between the isocyanate group and the aromatic ring.

The film which shape | molded the resin composition for polarizing plates in the film thickness of 80 micrometers is obtained from the resin composition for polarizing plates by the following method.
First, the resin composition for polarizing plates is dissolved in 1,3-dioxolane as an organic solvent so that the solid content is about 10%. Using a applicator, a film thickness of 80 μm on a 120 μm thick PET (polyethylene terephthalate) film [for example, “Cosmo Shine” manufactured by Toyobo Co., Ltd.], which is obtained by subjecting the resin composition for polarizing plate dissolved in an organic solvent to surface treatment. Apply so that The coating is dried at 80 ° C. for 2 hours. After drying, it is peeled off from the PET film and used for measurement of reflection chromaticity b *.

The polarizing plate formed from the polarizing plate resin composition of the present invention is preferably transparent.
The haze value of the polarizing plate is preferably 3% or less from the viewpoint of transparency.
The total light transmittance of the polarizing plate is preferably 85% or more from the viewpoint of colorability and transparency.

  The polarizing plate of the present invention uses the resin composition for a polarizing plate of the present invention to form a solution film forming method {coagulation method, casting method (band method, drum method, etc.)}, melt film forming method {T-die method (Cast method, uniaxial stretching method, sequential secondary stretching method, simultaneous secondary stretching method, etc.), ring die method (inflation method, tube method, etc.)} and a film formed by a known method such as a calendar method, It can be produced by stretching after impregnation and dyeing with an iodine ion solution.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited to these. Hereinafter, unless otherwise specified, “%” means “% by weight” and “part” means “part by weight”.

Production Examples 1 to 49 and Comparative Production Examples 1 to 25
[Synthesis of Modified Polysaccharide (A)]
The polysaccharides described in Tables 1 to 6 were added to 150 parts of dimethylacetamide and stirred at 150 ° C. for 1 hour. After cooling to 100 ° C., 15 parts of lithium chloride and 0.1 part of dibutyltin laurate were added to this solution, and the mixture was stirred for 24 hours while maintaining the temperature at 100 ± 20 ° C. Then, it cooled to 0 degreeC, 100 parts of pyridines and the compound (y2) were added to the reaction solution as described in Tables 1-6, and it stirred for 2 hours, keeping temperature at 0 +/- 5 degreeC. The reaction solution is added to 2000 parts of water, and the precipitate is collected by filtration, washed with 2000 parts of water, and dried under reduced pressure at 100 ° C. for 20 hours to modify the modified polysaccharides (A-1) to Tables 1 to 6 (A-49) and modified polysaccharides for comparison (A′-1) to (A′-25) were obtained.

In Tables 1-6, (y1) used what was manufactured by the following manufacture examples 50-54.
Production Example 50
[Monoisocyanate compound (y121) which is a reaction product of hexamethylene diisocyanate and methanol]
In a reaction vessel equipped with a stirrer, a condenser and a thermometer, 32 parts of methanol [manufactured by Tokyo Chemical Industry], 168 parts of hexamethylene diisocyanate [[trade name: Duranate HDI, produced by Asahi Kasei Chemical], and bismuth tri (2- 1 part of ethylhexanoate) (2-ethylhexanoic acid 50% solution) was added and reacted at 70 ° C. for 5 hours to obtain a monoisocyanate compound (y121).

Production Example 51
[Monoisocyanate compound (y122) which is a reaction product of isophorone diisocyanate and ethanol]
In Production Example 50, a monoisocyanate compound was similarly used except that “ethanol (manufactured by Tokyo Chemical Industry) 46 parts” instead of “methanol 32 parts” and “isophorone diisocyanate 222 parts” instead of “hexamethylene diisocyanate 168 parts” were used. (Y122) was obtained.

Production Example 52
[Monoisocyanate compound (y123) which is a reaction product of dicyclohexylmethane-4,4′-diisocyanate and n-butanol]
In Production Example 50, “n-butanol (manufactured by Tokyo Chemical Industry) 74 parts” instead of “32 parts of methanol” and “dicyclohexylmethane-4,4′-diisocyanate 262 parts” instead of “168 parts of hexamethylene diisocyanate” A monoisocyanate compound (y143) was obtained in the same manner except that it was used.

Production Example 53
[Monoisocyanate compound (y124) which is a reaction product of tolylene diisocyanate and octanol]
In Production Example 50, “octanol [manufactured by Tokyo Chemical Industry] 130 parts” was used in place of “32 parts of methanol”, and “pure range isocyanate [trade name: Sumidur T-80” instead of “168 parts of hexamethylene diisocyanate”. Monoisocyanate compound (y124) was obtained in the same manner except that “174 parts” manufactured by Sumika Bayer Urethane Co., Ltd.] was used.

Production Example 54
[Monoisocyanate compound (y125) which is a reaction product of xylylene diisocyanate and phenol]
In Production Example 50, 94 parts of “phenol [manufactured by Tokyo Chemical Industry]” instead of “32 parts of methanol”, and “xylylene diisocyanate [trade name: Desmodur 15, Sumika Bayer Urethane” instead of “168 parts of hexamethylene diisocyanate” A monoisocyanate compound (y125) was obtained in the same manner except that “118 parts” manufactured by the same company was used.

In addition, the following was used for each component of Tables 1-6.
Polysaccharide cellulose: “KC Flock W-50GK” manufactured by Nippon Paper Chemicals Co., Ltd.
Diacetylcellulose-1: manufactured by Daicel Corporation, “cellulose acetate L-20”
Diacetylcellulose-2: manufactured by Daicel Corporation, “cellulose acetate L-50”
Diacetylcellulose-3: “CA-394” manufactured by Eastman Chemical Co., Ltd.
Acetylbutyrylcellulose-1: “CAB551-0.2” manufactured by Eastman Chemical Co., Ltd.
Acetylbutyrylcellulose-2: “CAB381-0.5” manufactured by Eastman Chemical Co., Ltd.
Acetylpropionylcellulose-1: manufactured by Eastman Chemical Co., Ltd., “CAP482-0.5”
Acetylpropionylcellulose-2: manufactured by Eastman Chemical Co., Ltd., “CAP482-2.0”
Carboxymethylcellulose-1: “Sunrose F1400MC” manufactured by Nippon Paper Chemicals Co., Ltd.
Carboxymethylcellulose-2: Daicel Finechem Co., Ltd. “CMC2280”
Carboxymethyl ethyl cellulose: Sanyo Chemical Industries, “CMEC”
Cellulose acetate phthalate: Wako Pure Chemical Industries, Ltd. Hydroxypropylmethylcellulose phthalate: Shin-Etsu Chemical Co., Ltd., "HPMCP HP-50"
Hydroxypropyl methylcellulose hexahydrophthalate: “HPMCHP” manufactured by Shin-Etsu Chemical Co., Ltd.
Hydroxypropyl methylcellulose acetate phthalate: “HPMCAP” manufactured by Shin-Etsu Chemical Co., Ltd.
Hydroxypropyl methylcellulose acetate succinate: “AQOAT AS-MG” manufactured by Shin-Etsu Chemical Co., Ltd.
Hydroxyethylcellulose-1: “HEC-SP900” manufactured by Daicel Corporation
Hydroxyethyl cellulose-2: “HEC AX-15” manufactured by Sumitomo Seika Co., Ltd.
Hydroxypropyl cellulose: Nippon Soda Co., Ltd., “NISOO HPC”
Low-substituted hydroxypropyl cellulose: “LH-31” manufactured by Shin-Etsu Chemical Co., Ltd.
Methylcellulose-1: “METOLOSE SM-8000” manufactured by Shin-Etsu Chemical Co., Ltd.
Methylcellulose-2: Matsumoto Yushi Seiyaku Co., Ltd., “Marporose M-4000”
Ethyl cellulose-1: “Etocel” manufactured by Dow Chemical Co., Ltd.
Ethylcellulose-2: “Ethylcellulose 45CP” manufactured by Kanto Chemical Co., Inc.
Hydroxypropyl methylcellulose-1: Shin-Etsu Chemical Co., Ltd., “METOLOSE 90SH-4000”
Hydroxypropyl methylcellulose-2: Matsumoto Yushi Seiyaku Co., Ltd., “Marporose 60MP-4000”
Hydroxyethyl methylcellulose: “METOLOSE SNB60T” manufactured by Shin-Etsu Chemical Co., Ltd.
Starch: “Corn Starch White” manufactured by Nippon Corn Starch Co., Ltd.
Amylose: “Amyrose EX-I” manufactured by Hayashibara
Amylopectin: manufactured by Wako Pure Chemical Industries, Ltd. Glycogen: manufactured by Wako Pure Chemical Industries, Ltd., "Glycogen (derived from oysters)"
Chitin: Wako Pure Chemical Industries, Ltd. Chitosan: Wako Pure Chemical Industries, Ltd., "Chitosan 1000"
Agarose: “Agarose 1600” manufactured by Wako Pure Chemical Industries, Ltd.
Carrageenan: “Irish Moss (carrageenan)” manufactured by Wako Pure Chemical Industries, Ltd.
Heparin: Wako Pure Chemical Industries, “Heparin sodium”
Hyaluronic acid: “HA-F” manufactured by Kewpie Co., Ltd.
Pectin: Wako Pure Chemical Industries, Ltd., xyloglucan: Dainippon Sumitomo Pharma Co., Ltd., "Glorid 6C"
Xanthan gum: Wako Pure Chemical Industries, Ltd.

Moreover, the total introduction rate of the urethane group, urea group, amide group, and imide group in Tables 1-6 was calculated | required by the following.
<Calculation method of total introduction rate of urethane group, urea group, amide group and imide group>
Total introduction rate of urethane group, urea group, amide group and imide group = R / T ′ (1)
R: NMR integral value (R ₁ ) of hydrogen atom of urethane group substituted with hydroxyl group, carboxyl group and amino group of monosaccharide unit constituting modified polysaccharide (A), NMR integral of hydrogen atom of urea group The total integrated value R = obtained by applying the value (R ₂ ), the NMR integrated value (R ₃ ) of the hydrogen atom of the amide group, and the NMR integrated value (R ₄ ) of the hydrogen atom of the imide group to the following formula (2) _{R 1 + R 2/2 +} R 3 + R 4 (2)
T ′: NMR integral value of a hydrogen atom directly bonded to the 4-position carbon atom of the monosaccharide unit constituting the modified polysaccharide (A) <the total introduction rate of urethane group, urea group, amide group and imide group Measuring method>
Solvent: Deuterated dimethyl sulfoxide Device: AVANCE300 (manufactured by Nippon Bruker Co., Ltd.)
Frequency: 300MHz

Mn of the modified polysaccharide (A) was measured under the following conditions.
Apparatus: Gel permeation chromatography solvent: N, N′-dimethylformamide Detector: RI detector Reference material: Polystyrene sample concentration: 3 mg / ml
Column stationary phase: PLgel MIXED-B
Column temperature: 40 ° C

Examples 1-49 and Comparative Examples 1-25
100 parts of each of (A-1) to (A-49) produced in Production Examples 1 to 49 and (A'-1) to (A'-25) produced in Comparative Production Examples 1 to 25, polyvinyl alcohol { 10 parts each of Kuraray Poval PVA-117 (manufactured by Kuraray Co., Ltd.) and 1,000 parts of 1,3-dioxolane as a solvent were mixed together, mixed and stirred uniformly with a disperser, Examples 1 to 49 and The resin composition for polarizing plates of Comparative Examples 1-25 was produced.
In addition, 110 parts of (A-1) produced in Production Example 1 and 1000 parts of 1,3-dioxolane as a solvent were mixed together, mixed and stirred uniformly with a disperser, and the polarizing plate resin of Comparative Example 26 A composition was prepared.

Examples 50-54
Each compounding component of the compounding part number of Table 7 was mix | blended collectively, and it mixed and stirred uniformly with the disperser, and produced the resin composition for polarizing plates of Examples 50-54.

In addition, the following were used for each component in Table 7.
Polyvinyl alcohol: “Kuraray Poval PVA-117” manufactured by Kuraray Co., Ltd.
Cellulose acetate propionate-1: “CAP482-0.5” manufactured by Eastman Chemical Co., Ltd.
Cellulose acetate butyrate-2: “CAB381-0.5” manufactured by Eastman Chemical Co., Ltd.
Cellulose diacetate-3: “CA-394” manufactured by Eastman Chemical Co., Ltd.
Triacetyl cellulose: “LT-55” manufactured by Daicel Chemical Industries, Ltd.

[Creation of polarizing plate: Combination of solution casting method and uniaxial stretching method]
After heating each resin composition for polarizing plates obtained in Examples 1 to 54 and Comparative Examples 1 to 26 to 35 ° C. and casting on a stainless steel support, a dope solution using an endless belt casting apparatus. Was uniformly cast on a stainless steel belt support at a temperature of 33 ° C. and a width of 1500 mm. The temperature of the stainless steel belt was controlled at 20 ° C. On the stainless steel belt support, the solvent was evaporated until the amount of residual solvent in the cast (cast) film reached 80% by weight, and then peeled off from the stainless steel belt support with a peeling tension of 150 N / m. The peeled film was immersed in a 5% by weight aqueous solution of iodine / boric acid = 1/4 (weight ratio) for 5 minutes and then doubled in the direction perpendicular to the film transport direction using a tenter while applying heat at 150 ° C. Stretched. The residual solvent at the start of stretching was 10% by weight. After stretching, the film was dried at 155 ° C. for 60 seconds to obtain a film (film thickness 80 μm) after drying.

[Performance evaluation method of polarizing plate]

(1) Transmittance and haze (transparency)
Based on JIS-K7136, the transmittance and haze were measured using a total light transmittance measuring apparatus [trade name “haze-garddual” manufactured by BYK Gardner Co., Ltd.]. The transmittance is a value excluding the transmittance of the PET film as a base material, and the unit is% in all cases.

(2) Pencil hardness (surface hardness)
The pencil hardness was measured according to JIS K-5600-5-4.

(3) Positive birefringence Measured at room temperature using a Senarmon type compensator with a polarizing microscope. The orientation function was measured by polarized infrared dichroism.
As the positive birefringence, a value at a wavelength of 550 nm was measured.

(4) Reverse wavelength dispersion Using an automatic birefringence meter (KOBRAWR, Oji Scientific Co., Ltd.), in-plane retardation retardation (Re) (447), Re (590) and light with wavelengths of 447 nm, 590 nm and 750 nm By measuring Re (750) and taking the ratio, the values of Re (447) / Re (590) and Re (750) / Re (590) were determined.
In addition, as reverse wavelength dispersion, from the viewpoint of phase difference correction ability, Re (447) / Re (590) = 0.90 ± 0.04 and Re (750) / Re (590) = 1.02 ± 0. 0.04 is preferable, and those having a large difference between Re (447) / Re (590) and Re (750) / Re (590) within the above range have better phase difference correction capability.

(5) Polarization degree The same two polarizing plates of the present invention are overlapped so that the orientation direction is perpendicular, and the light transmittance is measured by a total light transmittance measuring device [trade name “haze-garddual” BYK guardner ( Measured using a The lower the light transmittance, the better the polarization.

A reflection chromaticity b * measurement film was produced by the following production method, and the reflection chromaticity b * was measured in accordance with JIS-Z8729.
<Method for producing film for reflection chromaticity b * measurement>
The polarizing plate resin composition was applied to a 120 μm-thick PET (polyethylene terephthalate) film [“Cosmo Shine” manufactured by Toyobo Co., Ltd.] using an applicator so as to have a film thickness of 80 μm. The coated material was dried at 80 ° C. for 2 hours. After drying, the film was peeled from the PET film to obtain a reflection chromaticity b * measurement film.
<Measurement of reflection chromaticity b *>
The reflection chromaticity b * was measured under the following measurement conditions.
Standard: White standard plate device; “Multi-light source spectral colorimeter MSC-2” manufactured by Suga Test Instruments Co., Ltd.

  From the results of Tables 8 and 9, it can be seen that the resin compositions for polarizing plates of Examples 1 to 54 of the present invention simultaneously have transparency, surface hardness, positive birefringence and reverse wavelength dispersion. This shows that it is excellent as a composition for polarizing plates.

  The resin composition for polarizing plate of the present invention is useful as a resin composition for obtaining a thin film polarizing plate having excellent transparency, polarization and reverse wavelength dispersion, and excellent surface hardness and positive birefringence. It is. Moreover, since the polarizing plate of this invention is a thin film, it is useful as a polarizing plate for projection type liquid crystal display devices, such as a touch panel.

Claims (10)

At least one functional group selected from the group consisting of a urethane group, a urea group, an amide group and an imide group is at least one of the functional groups of at least one polysaccharide selected from the group consisting of a hydroxyl group, a carboxyl group and an amino group. The resin composition for polarizing plates containing modified polysaccharide (A) and polyvinyl alcohol (B) chemically modified by the group. The modified polysaccharide (A) is a modified polysaccharide obtained by chemically modifying the following polysaccharide (a), and at least one of the monosaccharide units constituting the modified polysaccharide is represented by the following general formulas (1) to (6). The resin composition for polarizing plates according to claim 1, which has at least one structure selected from the group consisting of:
Polysaccharide (a): starch, glycogen, cellulose, chitin, chitosan, agarose, carrageenan, heparin, hyaluronic acid, pectin, xyloglucan, xanthan gum and their functional groups other than urethane group, urea group, amide group and imide group At least one polysaccharide selected from the group consisting of substituted polysaccharides;

[Wherein, X ^{1 to} X ¹³ are each independently a hydrogen atom or a substituent represented by the following general formula (7); at least one of X ^{1 to} X ³ is represented by the following general formula (7): And at least one of X ^{4 to} X ⁶ is a substituent represented by the following general formula (7); at least one of X ⁷ and X ⁸ is represented by the following general formula ( 7); at least one of X ¹⁰ and X ¹¹ is a substituent represented by the following general formula (7); at least one of X ¹² and X ¹³ is the following general formula A substituent represented by formula (7); Y is an oxygen atom or NH group, and Z is a hydroxyl group or a substituent represented by (8). ]

[Wherein, R ¹ represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 18 carbon atoms; * represents a substituent represented by the general formula (7) by a bond to which R ¹ is attached; In the general formulas (1) to (6), it represents binding to an oxygen atom and / or a nitrogen atom adjacent to X. ]

[Wherein R ² represents a monovalent hydrocarbon group having 1 to 18 carbon atoms or an alkylene polyoxyalkylene group; * represents a substituent represented by the general formula (8) by a bond to which R ² is attached; Represents bonding to Z in the general formula (5) and an adjacent carbon atom. ] The resin composition for a polarizing plate according to claim 2, wherein the polysaccharide (a) is at least one selected from the group consisting of cellulose, acylated cellulose (a1), etherified cellulose (a2) and etherified acylcellulose (a3). object. R ¹ in the general formula (7) is a methyl group, an ethyl group, an n-propyl group, an n-butyl group, a sec-butyl group, a t-butyl group, an n-hexyl group, a 2-ethylhexyl group, or an n-octyl group. The resin composition for polarizing plates according to claim 2 or 3, which is at least one substituent selected from the group consisting of n-dodecyl group, n-stearyl group and phenyl group. The number average molecular weight of polyvinyl alcohol (B) is 1000-100,000, The resin composition for polarizing plates in any one of Claims 1-4. Furthermore, the resin composition for polarizing plates in any one of Claims 1-5 containing esterified cellulose (C). The resin composition for a polarizing plate according to claim 6, wherein the esterified cellulose (C) is an alkyl esterified cellulose, and the alkyl has 1 to 18 carbon atoms. The resin composition for polarizing plates according to claim 6 or 7, wherein the esterified cellulose (C) is an esterified cellulose having at least one ester group selected from the group consisting of an acetate group, a propionate group and a butyrate group. Based on the weight of the resin composition for polarizing plates, the content of the modified polysaccharide (A) is 1 to 99.8% by weight, the content of the polyvinyl alcohol (B) is 0.1 to 98.9% by weight, and an ester. The resin composition for polarizing plates according to any one of claims 6 to 8, wherein the content of the modified cellulose (C) is 0.1 to 98.9% by weight. The polarizing plate formed from the resin composition for polarizing plates in any one of Claims 1-9.