JP2009107171A - Optical laminate sheet, and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminate sheet of excellent transparency. <P>SOLUTION: A support body 11 comprising a polyester is biaxially stretched. An easily adhesive layer 12 is formed on at least one face of the biaxial-stretched support body 11. The easily adhesive layer 12 contains two kinds of binders of a polyurethane resin and an acrylic resin having 30°C or higher in a glass transition point, and a carbodiimide crosslinker. A weight ratio of the polyurethane resin to the acrylic resin is 95:5 to 50:50. The film thickness of the easily adhesive layer 12 is 30 nm or larger to 200 nm or smaller. The easily adhesive layer 12 is formed by applying an aqueous application liquid and by drying it. The maximum temperature at a drying time is within a range of 120°C or higher to 170°C or lower. The easily adhesive layer 12 contains an organic or inorganic fine particle, and a sliding agent. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical laminated sheet and a method for producing the same, and in particular, an optical laminated sheet used as a constituent member for liquid crystal displays, plasma displays, organic EL displays, surface electrolytic displays (SED), CRT displays, and the like, and a method for producing the same. About.

  A polyester film, particularly a biaxially oriented polyester film, has a support made of polyester (hereinafter referred to as “polyester support”), and exhibits excellent transparency, dimensional stability, chemical resistance, and low moisture absorption. It is widely used as various optical films. For example, it is used as a base film for prism sheets, antireflection sheets, light diffusion sheets, absorption sheets, electromagnetic wave shielding sheets, toning sheets, antireflection sheets, antiglare sheets, hard coat sheets and the like used in liquid crystal displays.

  The base film used for such an optical film is required to have excellent transparency, and excellent adhesion to an optical functional layer (hereinafter referred to as “upper layer”) including a prism layer laminated thereon. Property (adhesiveness) is required. However, it is difficult to directly bond the polyester support and the upper layer with sufficient strength.

  Therefore, generally, a method of providing a coating layer called an easy-adhesion layer on a polyester support is used. For example, it is provided by applying a water-soluble coating solution containing a urethane resin on a polyester support. A base film having a layer (see Patent Document 1) and a base film having an easy-adhesion layer obtained by blending polyester and urethane on a polyester support have been proposed (see Patent Document 2).

Moreover, in patent document 2, sufficient adhesiveness is provided with respect to both the polyester support body and the upper layer by using an easily bonding layer as the lamination sheet comprised from the application layer of multiple structures. Further, there has been proposed an optical laminated sheet in which fine particles are contained in an easy-adhesion layer composed of a binder and carbodiimide to prevent the fine particles from peeling off while achieving both transparency and slipperiness (see Patent Document 3). Further, there has been proposed an optical liquid adhesive film in which an easy-adhesion layer is formed from polyester and polyurethane resin, thereby improving scratch resistance in a subsequent process such as a prism lens processing process (see Patent Document 4).
JP 2007-190817 A JP 2004-195775 A JP 2007-152886 A JP 2000-229395 A

  As described above, the laminated sheet used for the optical film is required to have excellent transparency in addition to adhesiveness. Therefore, a clear film with less haze is required. However, depending on the environmental conditions on which the laminated sheet is placed, the polyester oligomer generated by the drying treatment at the time of forming the easy-adhesion layer is deposited on the surface of the easy-adhesion layer from the interface with the support or within the easy-adhesion layer. Precipitation of this polyester oligomer causes haze to increase or haze to increase uniformly, resulting in white turbidity unevenness (hereinafter referred to as “whitening unevenness”) and a loss of transparency.

  The present invention proposes an optical laminated sheet having a good coated surface shape, less haze increase and whitening unevenness due to the influence of storage environment conditions, and excellent adhesion to a polyester support and an upper layer, and a method for producing the same. For the purpose.

  As a result of intensive studies on the above problems, the present inventor has found that the occurrence of whitening unevenness is remarkable when the laminated sheet is stored under high temperature and high humidity of 35 ° C. and 80% RH or higher. Based on this finding, the present invention has been accomplished.

  The optical laminated sheet of the present invention has a support made of polyester and an easy-adhesion layer formed on at least one surface of the support, and has a glass transition point of 30 ° C. or higher polyurethane resin and glass transition point The easy-adhesion layer contains two types of binders of acrylic resin having a temperature of 30 ° C. or higher and a carbodiimide-based crosslinking agent.

  The easy adhesion layer is preferably provided after biaxially stretching the support. The weight ratio of the polyurethane resin to the acrylic resin is preferably 95: 5 to 50:50. The film thickness of the easy adhesion layer is preferably 30 nm or more and 200 nm or less. The easy-adhesion layer is formed by applying an aqueous coating solution and drying, and the maximum temperature during drying is preferably in the range of 120 ° C. or more and 170 ° C. or less. The easy adhesion layer preferably contains organic or inorganic fine particles and a slip agent.

  In the method for producing an optical laminated sheet of the present invention, a biaxial stretching step of biaxially stretching a support made of polyester, an aqueous coating liquid is applied to at least one surface of the stretched support, and dried. An easy-adhesive layer forming step for forming an adhesive layer, and the aqueous coating solution includes two types of binders, a polyurethane resin having a glass transition point of 30 ° C. or higher and an acrylic resin having a glass transition point of 30 ° C. or higher, and a carbodiimide. And a cross-linking agent. It is preferable that the weight ratio of the polyurethane resin to the acrylic resin is 95: 5 to 50:50, and the maximum temperature during drying in the easy-adhesion layer forming step is in a range of 120 ° C. or more and 170 ° C. or less.

  According to the present invention, two types of polyurethane resin having a glass transition point of 30 ° C. or higher and an acrylic resin having a glass transition point of 30 ° C. or higher are provided. By including the binder and the carbodiimide-based crosslinking agent in the easy-adhesion layer, it is possible to suppress the increase in haze and the occurrence of whitening unevenness due to the influence of the storage environment conditions. Moreover, an application surface shape can be made favorable by the weight ratio of a polyurethane resin and an acrylic resin being 95: 5-50: 50. In addition, an aqueous coating solution is applied and dried to form an easy-adhesion layer, and the maximum temperature during drying is in the range of 120 ° C. or higher and 170 ° C. or lower to improve the adhesion between the support and the upper layer. Can do.

  As shown in FIG. 1, the laminated sheet 10 of this invention is comprised from the support body 11 which consists of polyester, and the easily bonding layer 12 formed in at least one surface of this support body 11. As shown in FIG.

[Polyester support]
The support 11 of the present invention is a polyester base film made of polyester. As the polyester, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polybutylene naphthalate, or the like can be used. Among these, polyethylene terephthalate is particularly preferable from the viewpoint of cost and mechanical strength. However, the polyester that can be used in the present invention is not particularly limited.

  The polyester of the present invention is preferably stretched in order to improve mechanical strength, and particularly preferably biaxially stretched. Although there is no restriction | limiting in particular in a draw ratio, 1.5-7 times are preferable, More preferably, it is about 2-5 times. In particular, biaxially stretched products that are stretched about 2 to 5 times in the vertical and horizontal directions are preferable. If the draw ratio is less than 1.5 times, sufficient mechanical strength cannot be obtained. Conversely, if it exceeds 7 times, it becomes difficult to obtain a uniform thickness.

  The thickness of the support is preferably from 30 μm to 500 μm, and more preferably from 100 μm to 300 μm. When the thickness is less than 30 μm, it is not preferable because it becomes stiff and difficult to handle. On the other hand, when the thickness exceeds 500 μm, it is difficult to reduce the size and weight of the display device, and it is disadvantageous in terms of cost.

  The easy adhesion layer 12 is a layer directly laminated on the support 11. The easy-adhesion layer 12 must contain a binder, but it is preferable to further contain a compound having a plurality of carbodiimide structures in the molecule. The easy adhesion layer 12 may contain fine particles, a surfactant, and an antistatic agent as necessary.

  The easy adhesion layer 12 uses a polymer such as a polyurethane resin having a glass transition point of 30 ° C. or higher and an acrylic resin having a glass transition point of 30 ° C. or higher as a binder. The easy-adhesion layer 12 has good compatibility with the support 11 made of polyester, and uses an acrylic resin having a glass transition point of 30 ° C. or higher and a polyurethane resin having a glass transition point of 30 ° C. or higher as a binder. Increase in haze and occurrence of uneven whitening can be remarkably suppressed. In the easy-adhesion layer 12, it is preferable to employ a polyurethane resin as the main binder. Thereby, the easily bonding layer 12 can make compatible both adhesion | attachment of the support body 11 and the upper layer which is an optical function layer.

    The polyurethane resin is a general term for polymers having a urethane bond in the main chain, and is usually obtained by reaction of polyisocyanate and polyol. Examples of the polyisocyanate include TDI, MDI, NDI, TODI, HDI, and IPDI. Examples of the polyol include ethylene glycol, propylene glycol, glycerin, and hexanetriol. As the isocyanate of the present invention, a polymer obtained by subjecting a polyurethane polymer obtained by the reaction of polyisocyanate and polyol to chain extension treatment to increase the molecular weight can also be used. The polyisocyanate, polyol and chain extension treatment described above are described in, for example, “Polyurethane Resin Handbook” (edited by Keiji Iwata, Nikkan Kogyo Shimbun, published in 1987).

  An acrylic resin is a polymer containing acrylic acid, methacrylic acid and derivatives thereof as components. Specific examples include acrylic acid, methacrylic acid, methyl methacrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, acrylamide, acrylonitrile, hydroxyl acrylate, and the like as main components, and monomers copolymerizable therewith (for example, styrene, And polymers obtained by copolymerization of divinylbenzene and the like.

  As the binder, the above polymer may be dissolved in an organic solvent, or an aqueous dispersion may be used. However, since the environmental load is small, it is preferable to perform aqueous coating using an aqueous dispersion. A commercially available polymer may be used as the aqueous dispersion. For example, Superflex 830, 460, 870, 420, 420NS (trade name: polyurethane manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Bondic 1370NS, 1320NS (trade name: Large) Polyurethane manufactured by Nippon Ink Chemical Co., Ltd.), Jurimer ET325, ET410, SEK301 (trade name: Nippon Pure Chemicals Co., Ltd. acrylic), Boncoat AN117, AN226 (trade name: Dainippon Ink Chemical Co., Ltd. acrylic) , Luck Star DS616, DS807 (trade name: Dainippon Ink and Chemicals Co., Ltd. styrene-butadiene rubber), Nippon LX110, LX206, LX426, LX433 (trade name: Nippon Zeon Co., Ltd. styrene-butadiene rubber), Nippon LX513, LX1551, L 550, LX1571 (trade name: Acrylonitrile-butadiene rubber manufactured by Nippon Zeon Co., Ltd.), Finetex Es650, Es2200 (trade name: polyester manufactured by Dainippon Ink & Chemicals, Inc.), Vironal MD1400, MD1480 (trade name: Toyobo ( Polyester)) and the like.

  The weight ratio of the polyurethane resin to the acrylic resin is 95: 5 to 50:50, preferably 90:10 to 70:30. By setting such a weight ratio, a good coated surface shape can be obtained. The molecular weight of the polymer used as the binder is not particularly limited, but it is usually preferable to use a polymer having a weight average molecular weight of about 3000 to 1000000. However, when the polymer having a weight average molecular weight of less than 3000 is used, the strength of the easy adhesion layer 12 may be insufficient. On the other hand, when the polymer having a weight average molecular weight of more than 1000000 is used, the surface of the easy adhesion layer 12 is poor. There is.

  As the “compound having a plurality of carbodiimide structures in the molecule” (hereinafter referred to as a carbodiimide compound as appropriate) used in the present invention, any compound having a plurality of carbodiimide groups in the molecule can be used without particular limitation. be able to. Polycarbodiimide is usually synthesized by condensation reaction of organic diisocyanate, but the organic group of the organic diisocyanate used in this synthesis is not particularly limited, either aromatic or aliphatic, or a mixture thereof It can be used. However, aliphatic systems are particularly preferred from the viewpoint of reactivity. As the synthetic raw material, organic isocyanate, organic diisocyanate, organic triisocyanate and the like are used.

  As examples of organic isocyanates, aromatic isocyanates, aliphatic isocyanates, and mixtures thereof can be used. Specifically, 4,4'-diphenylmethane diisocyanate, 4,4-diphenyldimethylmethane diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, hexamethylene diisocyanate, cyclohexane Diisocyanate, xylylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 1,3-phenylene diisocyanate, etc. are used, and organic monoisocyanates include isophorone isocyanate, phenyl isocyanate. Cyclohexyl isocyanate, butyl isocyanate, naphthyl isocyanate and the like are used. Moreover, the carbodiimide type compound which can be used for this invention is also available as commercial items, such as carbodilite V-02-L2 (brand name: Nisshinbo Co., Ltd. product).

  It is preferable to add the carbodiimide type compound of this invention in the range of 1-200 mass% with respect to a binder, More preferably, it is adding in the range of 5-100 mass%. When the addition amount is less than 1% by mass, when the easy-adhesion layer 12 contains fine particles, the prevention of fine particle peeling may be insufficient. On the other hand, when the addition amount exceeds 200% by mass, the surface state of the easy-adhesion layer may be deteriorated.

  Moreover, you may use various additives, such as microparticles | fine-particles and surfactant other than the above, for the easily bonding layer 12 according to a use. As the fine particles that can be used in the easy-adhesion layer 12 of the present invention, either organic or inorganic fine particles can be used. For example, polymer fine particles such as polystyrene, polymethyl methacrylate, silicone resin, and benzoguanamine resin, and inorganic fine particles such as silica, calcium carbonate, magnesium oxide, and magnesium carbonate can be used. Among these, polystyrene, polymethyl methacrylate, and silica are preferable from the viewpoint of the effect of improving the slipperiness and cost.

The average particle size of the fine particles used in the present invention is preferably from 0.3 μm to 12 μm, more preferably from 0.5 μm to 9 μm. If the average particle size of the fine particles is less than 0.3 μm, the effect of improving the slipping property is insufficient. On the other hand, if the average particle size exceeds 12 μm, the display quality of the display device may be deteriorated. Further, the amount of the fine particles of the present invention varies depending on the average particle diameter, but is preferably 0.1 mg / m ² or more and 30 mg / m ² or less, more preferably 0.5 mg / m ² or more and 20 mg / m. ² or less. If the addition amount of the fine particles is less than 0.1 mg / m ² , the effect of improving the slip property may be insufficient. On the other hand, if the addition amount exceeds 30 mg / m ² , the transparency is lowered and the display of the display device is reduced. There is a risk of degrading quality. The average particle size of the fine particles referred to in the present invention is the particle size obtained for any 50 fine particles when the diameter of a circle having the same area as the fine particles when the fine particles were photographed with a scanning electron microscope was used as the particle size. Mean diameter.

Examples of the surfactant that can be used for the easy-adhesion layer 12 include known anionic, nonionic, and cationic surfactants. The surfactant is described in, for example, “Surfactant Handbook” (Nishi Ichiro, Imai Junichiro, Sho Kasai edited by Sangyo Kasho Co., Ltd., 1960). Further, the addition amount of the surfactant is preferably 0.1 mg / m ² or more and 30 mg / m ² or less, more preferably 0.2 mg / m ² or more and 10 mg / m ² or less. If the addition amount of the surfactant is less than 0.1 mg / m ² , repelling may occur. On the other hand, if it exceeds 30 mg / m ² , the surface state of the easy adhesion layer 12 may be deteriorated.

An antistatic agent can also be used for the easy-adhesion layer 12. The type of the antistatic agent is not particularly limited. For example, an electron transmission polymer such as polyaniline or polypyrrole, an ion transmission polymer having a carboxyl group or a sulfonic acid group in the molecular chain, conductive fine particles, etc. Is mentioned. Among these, the conductive tin oxide fine particles described in JP-A-61-20033 can be preferably used from the viewpoints of conductivity and transparency. The addition amount of the antistatic agent is preferably added so that the surface resistivity of the easy-adhesion layer 12 measured in an atmosphere of 25 ° C. and 30% RH is 1 × 10 ⁵ Ω or more and 1 × 10 ¹³ Ω or less. If the surface resistivity is less than 1 × 10 ⁵ Ω, the addition amount of the antistatic agent increases, so that the transparency of the laminated sheet may be lowered. If the surface resistivity exceeds 1 × 10 ¹³ Ω, the antistatic effect becomes insufficient. On the other hand, there is a risk of inconvenience such as dust adhering.

Scratch resistance is imparted to the easy-adhesion layer 12 by adding a slipping agent to the easy-adhesion layer 12 in addition to the organic or inorganic fine particles. Thereby, the easily bonding layer 12 can also serve as a protective film. The type of the slipping agent is not particularly limited, but as a slipping agent that can be suitably used, for example, a synthetic or natural wax, a silicone compound, R—O—SO ₃ M (where R is substituted or non-substituted) substituted alkyl group _{(C n H 2n + 1 -} ; n is an integer of 3 to 20), M is a compound represented by a monovalent metal atom) and the like.

In addition, specific examples of the slipping agent include cellosol 524, 428, 428, 732-B, 920, B-495, hydrin P-7, D-757, Z-7-30, E-366, F- 115, D-336, D-337, Polylon A, 393, H-481, Hymicron G-110F, 930, G-270 (trade name: manufactured by Chukyo Yushi Co., Ltd.), Chemipearl W100, W200, W300, Wax type such as W400, W500, W950 (trade name: manufactured by Mitsui Chemicals), KF-412, 413, 414, 393, 859, 8002, 6001, 6002, 857, 410, 910, 851, X- 22-162A, X-22-161A, X-22-162C, X-22-160AS, X-22-164B, X-22-164C, X-22-170B X-22-800, X-22-819, X-22-820, X-22-821 ( trade name: manufactured by Shin-Etsu Chemical Co., Ltd.) silicone and the _{like, C 16 H 33 -O-SO} 3 _{Na, C 18 H 37 -O-} SO 3 represented by the general formula Na, and the like compounds. The addition amount of these slip agent is preferably to 0.1 mg / ^{m 2} or more 50 mg / ^{m 2} or less, more preferably 1 mg / ^{m 2} or more 20 mg / ^{m 2} or less. However, if the addition amount is less than 0.1 mg / m ² , the easy-adhesion layer 12 may have insufficient sliding properties, while if it exceeds 50 mg / m ² , the surface shape of the easy-adhesion layer 12 may be insufficient. May get worse.

  The coating thickness of the easy adhesion layer is 30 nm to 200 nm, preferably 40 nm to 100 nm. By setting it as such a coating film thickness, it becomes a coating surface shape with a favorable interference fringe. If the coating film thickness is less than 30 nm, the adhesion to the support 11 becomes insufficient, while if the coating film thickness exceeds 200 nm, the surface state may deteriorate.

  The method for forming the easy-adhesion layer 12 is not particularly limited, and known methods such as bar coater coating and slide coater coating can be used. Moreover, after application | coating, it dries and the maximum temperature at the time of this drying is 120 to 170 degreeC, Preferably it is 130 to 150 degreeC. By setting it as such maximum temperature, generation | occurrence | production of the oligomer under the easily bonding layer 12 or in the easily bonding layer 12 is suppressed, and favorable adhesiveness with the support body 11 is obtained.

  When coating, a solvent (coating solvent) can be used. As the coating solvent, water, toluene, methyl alcohol, isopropyl alcohol, methyl ethyl ketone, and the like, and aqueous and organic solvent based coating solvents such as a mixed system thereof can be used. Among these, the method using water as a coating solvent is preferable in view of cost and ease of production.

  Moreover, application | coating may be performed after extending | stretching to a uniaxial direction, and may be performed after extending biaxially. However, in order to enable recovery of the base ear after lateral stretching, it is preferable to apply after biaxial stretching. In addition, it is preferable to form the easily bonding layer 12 with respect to the support body 11 not only on one side but on the other side.

    The laminated sheet of the present invention can be used as an optical film for use in liquid crystal displays, plasma displays, organic EL displays, and CRT displays. About these display devices, for example, “Display Advanced Technology” (published by Chizuka Tani, Kyoritsu Publishing Co., Ltd. 1998), “EL, PDP, LCD Display” (Toray Research Center Co., Ltd. issued in 2001), It is described in detail in “Color LCD” (Shunsuke Kobayashi, Sangyo Tosho Publishing Co., Ltd., published in 1990).

  In addition, an optical sheet having a laminated sheet obtained by the present invention and at least one of a prism layer, an antireflection layer, a light diffusion layer, an antiglare layer, and a hard coat layer exhibits excellent optical properties. Specific examples of these include prism sheets, antireflection sheets, light diffusion sheets, hard coat sheets, plasma display IR absorption sheets, electromagnetic wave shield sheets, toning sheets and the like used in liquid crystal displays. For example, In addition to the literature, it is described on page 74 of the August 2002 issue of Electric Journal.

[Example 1]
Hereinafter, the laminated sheet of the present invention and the production method thereof will be described with reference to Examples 1 to 7 and Comparative Examples 1 to 4. In addition, in the following Examples etc., when the manufacturing method etc. of the lamination sheet 10 are the same, it shall explain in detail in Example 1, and abbreviate | omits description in others.

  A laminated sheet support was formed by the following procedure. First, a polyethylene terephthalate (hereinafter referred to as PET) resin having an intrinsic viscosity of 0.66, polycondensed using Ge as a catalyst, is dried to a moisture content of 50 ppm or less, the heater temperature is set to 280 to 300 ° C., and melted in an extruder. It was. The melted PET resin was discharged from a die part onto a chill roll electrostatically applied to obtain an amorphous base. The obtained amorphous base was stretched 3.3 times in the base traveling direction, and then stretched 3.8 times in the width direction to obtain a support having a thickness of 188 μm.

The support having a thickness of 188 μm formed as described above was transported at a transport speed of 80 m / min and subjected to corona discharge treatment under conditions of 730 J / m ^{2 on} both surfaces, and then the coating amount on both surfaces was 4.4 cm ^3. / M ² , an easy-adhesion layer coating solution was applied by a bar coating method. And this was dried at 160 degreeC for 1 minute, and the laminated sheet with which the easily bonding layer was apply | coated to both surfaces of the support body was obtained by forming an easily bonding layer. In addition, the film thickness of the easily bonding layer was measured by observing a lamination sheet by the magnification 200,000 times using the transmission electron microscope (JEM2010 (Nippon Denka Co., Ltd. product)).

[Prescription of coating solution for easy adhesion layer]
A coating solution for an easy adhesion layer having the following formulation was used.
30.7 parts by mass of urethane resin binder (manufactured by Mitsui Chemicals, Olester UD350, solid content 38%, glass transition temperature 33 ° C.)
4.2 parts by mass of acrylic resin binder (manufactured by Daicel Finechem Co., Ltd., AS563, solid content 27.5%, glass transition temperature 47 ° C.)
5.8 parts by mass of a crosslinking agent (Nisshinbo Co., Ltd., Carbodilite V-02-L2, solid content 40%)
Additive (filler) 1.9 parts by mass (Nippon Aerosil Co., Ltd., Aerosil OX-50, solid content 10%)
Additive (filler) 0.8 parts by mass (manufactured by Nissan Chemical Co., Ltd., Snowtex XL, solid content 40%)
Additive (sliding agent) 1.9 parts by mass (manufactured by Chukyo Yushi Co., Ltd., cellosol 524, solid content 30%)
Surfactant 1 15.5 parts by mass (manufactured by NOF Corporation, Rapisol B-90, anionic 1%)
Surfactant 2 19.4 parts by mass (manufactured by Sanyo Chemical Industries, NAROACTY-CL-95, 1% nonionic property)
Distilled water added to total 1000 parts by mass

[Adhesion between support and easy-adhesion layer]
A laminated sheet obtained by applying an easy-adhesion layer to the support used in the Examples was immersed in distilled water at 60 ° C. for 16 hours, and water droplets adhering to the sample surface were then removed from paper (Kimwipe S-200, Crecia). Immediately after lightly wiping with a scratch strength tester (HEIDEN-18, manufactured by Shinto Kagaku Co., Ltd.), the surface of the sample was rubbed with a 0.1R diamond needle, and the rubbed portion was observed with a microscope. The degree of peeling of the easy-adhesion layer when observed at a magnification of 100 was visually determined according to the following criteria, and the adhesion between the support and the easy-adhesion layer was evaluated. The load applied to the diamond needle was 200 g.
Rank A: When there is no peeling Rank B: When the peeled area is less than 30% with respect to the area of the portion rubbed with the diamond needle Rank C: With respect to the area of the portion rubbed with the diamond needle 30% or more and less than 70% D rank: When the peeled area is 70% or more and 100% or less of the area rubbed with the diamond needle E rank: In addition to the portion rubbed with the diamond needle, its peripheral part When peeling occurs to the coating layer

[Adhesion between upper layer and easy-adhesion layer]
・ Condition A
The prepared laminated sheet was conditioned for 24 hours in an atmosphere of 25 ° C. and 60% RH, and then the coating amount after drying using a bar coater was 20 g / m on the sample surface of the obtained laminated sheet. ^{The following} coating solution was applied so as to be ^2, and dried at 140 ° C. for 2 minutes. Using a single-blade razor on the surface of this coating layer, six vertical and horizontal scratches were made to form 25 squares. Next, a cellophane tape (No. 405 manufactured by Nichiban Co., Ltd., 24 mm width) is applied on this, and then completely adhered by rubbing with poppy rubber from above, and then peeled off in the direction of 90 ° to peel off the peeled-off mesh By determining the number, the following ranking was performed to evaluate the adhesion between the upper layer and the easy adhesion layer. The width of the scratch was 3 mm both vertically and horizontally.
Rank A: No peeling B rank: When the number of peeled squares is less than 1 Rank C: When the number of peeled squares is 1 or more and less than 3 D Rank: When the number of peeled squares is 3 or more and less than 20, Rank E : When the number of peeled cells is 20 or more / Condition B
After the upper layer coated product prepared in Condition A is placed in warm water at 80 ° C. for 3 hours, water droplets adhering to the sample surface are wiped off with paper (Kimwipe S-200) and gauze, and the surface is dry. As with A, a peel test was performed with a cellophane tape using a single-blade razor. Ranking was the same as in Condition A.

[Coating liquid formulation for upper layer]
235 parts by mass of acrylic resin (Acridic A811BE, manufactured by Dainippon Ink & Chemicals, Inc., solid content 50%)
30 parts by mass of isocyanate compound (Takenate D110N, manufactured by Mitsui Takeda Chemical Co., Ltd.)
Methyl ethyl ketone added to total 1000 parts by mass

[Interference unevenness]
The prepared laminated sheet was irradiated on a coated layer with diffused light from a fluorescent lamp through a milky white acrylic plate from a desk on which a black doskin cloth was laminated, and the reflected light generated was visually observed. And the rainbow-shaped interference nonuniformity observed at this time was judged by the following reference | standard, and this was evaluated as a coating surface shape. Moreover, in visual judgment, the blackening process was performed with respect to the sample as forced condition evaluation, and it adjusted so that the transmittance | permeability of 500 nm light might be set to 1% or less. As blackening treatment, magic ink (artline oil-based marker supplement ink KR-20 black, manufactured by shachihata Co., Ltd.) was applied to the surface of the sample opposite to the surface to be observed, and then dried. .
Rank A: Irregular interference unevenness is not visually confirmed in both the blackened sample and the untreated sample.
Rank B: Irregular interference unevenness is visually confirmed in the sample after the blackening treatment, but is not confirmed in the untreated sample.
Rank C: Rainbow-like interference unevenness is visually confirmed in both the blackened sample and the untreated sample.

[Haze measurement]
Using a haze meter (NDH-1001P, Nippon Denshoku Industries Co., Ltd.), the haze of the completed laminated sheet was measured based on the method described in the haze value of JIS-K-6714-1977. Measure the haze of both the sample after conditioning the prepared laminate sheet at 40 ° C and 90% RH for one day and the sample before conditioning, and subtract the haze before conditioning from the humidity after conditioning The value was taken as Δhaze.

[Whitening unevenness]
The prepared easy-adhesion sheet was conditioned for 1 day under conditions of 40 ° C. and 90% RH, then irradiated with a light from a tungsten light source on a desk on which a black doskin cloth was laminated, and the reflected light generated was visually observed. The cloudy unevenness observed at this time was judged according to the following criteria, and this was evaluated as whitening unevenness.
Rank A: No whitening unevenness is visually confirmed.
Rank B: Unevenness of whitening is confirmed when the reflected light from the sample is viewed from the viewpoint of 20 degrees or less with respect to the desk on which the sample is placed.
Rank C: Whitening unevenness is confirmed when the reflected light from the sample is viewed at a 45-degree line or more with respect to the desk on which the sample is placed.

〔Glass-transition temperature〕
The glass transition temperature of the dried binder for an easy-adhesion layer was measured using DSC (TA Instrument Co., Ltd. Q-1000) under the condition of a heating rate of 5 ° C./min.

[Example 2]
A laminated sheet was prepared in the same manner as in Example 1 except that the binder ratio of the coating solution formulation for the easy adhesion layer was changed. Specifically, the ratio of the resin binder in the coating solution formulation for the easy-adhesion layer was changed as follows, and all other additives were the same as in Example 1.
23.9 parts by mass of urethane resin binder (manufactured by Mitsui Chemicals, Olester UD350, solid content 38%, glass transition temperature 33 ° C.)
Acrylic resin binder 12.6 parts by mass (AS563, solid content 27.5%, glass transition temperature 47 ° C., manufactured by Daicel Finechem Co., Ltd.)

[Example 3]
A laminated sheet was prepared in the same manner as Example 1 except that the coating solution formulation for the easy adhesion layer was changed.
15.4 parts by mass of urethane resin binder (manufactured by Mitsui Chemicals, Olester UD350, solid content 38%, glass transition temperature 33 ° C.)
2.1 parts by mass of acrylic resin binder (AS563 manufactured by Daicel Finechem Co., Ltd., 27.5% solid content, glass transition temperature 47 ° C.)
2.9 parts by mass of cross-linking agent (Nisshinbo Co., Ltd., Carbodilite V-02-L2, solid content 40%)
Additive (filler) 0.95 parts by mass (Nippon Aerosil Co., Ltd., Aerosil OX-50, solid content 10%)
Additive (filler) 0.4 parts by mass (manufactured by Nissan Chemical Co., Ltd., Snowtex XL, solid content 40%)
0.95 parts by mass of additive (slip agent) (manufactured by Chukyo Yushi Co., Ltd., cellosol 524, solid content 30%)
Surfactant 1 7.8 parts by mass (Nippon Yushi Co., Ltd., Rapisol B-90, anionic 1%)
Surfactant 2 9.7 parts by mass (Sanyo Chemical Industry Co., Ltd., NAROACTY-CL-95, Nonionicity 1%)
Distilled water added to total 1000 parts by weight

[Example 4]
A laminated sheet was prepared in the same manner as in Example 1 except that the coating amount of the easy-adhesion layer coating solution was changed to 8.8 cm ³ / m ² .

[Example 5]
A laminated sheet was prepared in the same manner as in Example 1 except that the condition for applying and drying the easy-adhesion layer coating solution was changed to drying at 130 ° C. for 1 minute.

[Example 6]
A laminated sheet was prepared in the same manner as in Example 1 except that the coating solution formulation for the easy adhesion layer was changed to the following formulation.
[Coating liquid formulation for easy adhesion layer]
30.7 parts by mass of urethane resin binder (manufactured by Mitsui Chemicals, Olester UD350, solid content 38%, glass transition temperature 33 ° C.)
3.8 parts by mass of acrylic resin binder (Jurimer ET410, solid content 30%, glass transition temperature 35 ° C, manufactured by Nippon Pure Chemical Co., Ltd.)
5.8 parts by mass of a crosslinking agent (Nisshinbo Co., Ltd., Carbodilite V-02-L2, solid content 40%)
Additive (filler) 1.9 parts by mass (Nippon Aerosil Co., Ltd., Aerosil OX-50, solid content 10%)
Additive (filler) 0.8 parts by mass (manufactured by Nissan Chemical Co., Ltd., Snowtex XL, solid content 40%)
Additive (sliding agent) 1.9 parts by mass (manufactured by Chukyo Yushi Co., Ltd., cellosol 524, solid content 30%)
Surfactant 1 15.5 parts by mass (Nippon Yushi Co., Ltd., Rapisol B-90, anionic 1%)
Surfactant 2 19.4 parts by mass (Sanyo Chemical Industry Co., Ltd., NAROACTY-CL-95, Nonionicity 1%)
Distilled water added to total 1000 parts by weight

[Example 7]
The resin binder ratio of the easy-adhesion layer coating solution used in Example 1 was changed as follows, and the other additives were formulated in the same manner as in Example 1. A laminated sheet was prepared in the same manner as in Example 1 except for the coating liquid formulation.
13.6 parts by mass of urethane resin binder (manufactured by Mitsui Chemicals, Olester UD350, solid content 38%, glass transition temperature 33 ° C.)
Acrylic resin binder 28.3 parts by mass (AS563, solid content 27.5%, glass transition temperature 47 ° C., manufactured by Daicel Finechem Co., Ltd.)

[Comparative Example 1]
In Comparative Example 1, a coating layer was formed in the same manner as the formulation of Example 1 except that the crosslinking agent was removed from the formulation of the coating solution for the easy adhesion layer. A laminated sheet was prepared in the same manner as Example 1 except for the coating solution formulation for the easy adhesion layer.

[Comparative Example 2]
In Comparative Example 2, in the coating liquid formulation for the easy adhesion layer, the urethane resin binder was 34.1 parts by mass with respect to 30.7 parts by mass of Example 1, and the acrylic resin binder was removed, and Example 1 and A laminated sheet was prepared in the same manner.

[Comparative Example 3]
In Comparative Example 3, the urethane resin binder of the easy-adhesion layer coating solution used in Example 1 was changed as follows, and other additives were formulated in the same manner as in Example 1. A laminated sheet was prepared in the same manner as in Example 1 except for the coating liquid formulation.
35.3 parts by mass of urethane resin binder (manufactured by Enomoto Chemical Co., Ltd., Neoletz R600, solid content 33% glass transition temperature -22 ° C)

[Comparative Example 4]
In Comparative Example 4, a laminated sheet was prepared in the same manner as Example 1 except for the coating solution formulation for the easy adhesion layer.
46.7 parts by mass of polyester resin binder (manufactured by Kyoyo Chemical Industry Co., Ltd., plus coat Z687, solid content 25% glass transition temperature 110 ° C.)
4.2 parts by mass of acrylic resin binder (AS563, solid content 27.5%, glass transition temperature 47 ° C., manufactured by Daicel Finechem Co., Ltd.)
5.8 parts by mass of a crosslinking agent (Nisshinbo Co., Ltd., Carbodilite V-02-L2, solid content 40%)
Additive (filler) 1.9 parts by mass (Nippon Aerosil Co., Ltd., Aerosil OX-50, solid content 10%)
Additive (filler) 0.8 parts by mass (Nissan Chemical Co., Ltd., Snowtex XL, solid content 40%)
Additive (sliding agent) 1.9 parts by mass (manufactured by Chukyo Yushi Co., Ltd., cellosol 524, solid content 30%)
Surfactant 1 15.5 parts by mass (Nippon Yushi Co., Ltd., Rapisol B-90, anionic 1%)
Surfactant 2 19.4 parts by mass (Sanyo Chemical Industry Co., Ltd., NAROACTY-CL-95, Nonionicity 1%)
Distilled water added to total 1000 parts by weight

上記実施例及び比較例の評価結果を表１にまとめて示す。実施例１〜７のヘイズは１％以下であり、高温高湿下でのヘイズ変化（Δヘイズ）も０．３％以内であり、透明性が高く、且つ干渉ムラも良好な積層シートが得られた。また、接着性についても、支持体／易接着層及び上層／易接着層の評価でも良好な接着性が得られた。一方、比較例１については、支持体／易接着層での密着が劣り、比較例４については、上層／易接着層での接着性評価の温水条件での接着が得られなかった。比較例２及び３については、Δヘイズが大きく、白化ムラも悪かった。比較例４については、干渉ムラが劣った。

The evaluation results of the above examples and comparative examples are summarized in Table 1. The haze of Examples 1 to 7 is 1% or less, the haze change (Δhaze) under high temperature and high humidity is within 0.3%, and a laminated sheet having high transparency and good interference unevenness is obtained. It was. Also, regarding the adhesiveness, good adhesiveness was also obtained in the evaluation of the support / easy-adhesive layer and the upper layer / easy-adhesive layer. On the other hand, in Comparative Example 1, the adhesion at the support / easy-adhesive layer was inferior, and in Comparative Example 4, adhesion under hot water conditions for evaluation of adhesion at the upper layer / easy-adhesive layer was not obtained. In Comparative Examples 2 and 3, Δhaze was large and whitening unevenness was also bad. In Comparative Example 4, the interference unevenness was inferior.

It is principal part sectional drawing of the lamination sheet to which this invention is applied.

Explanation of symbols

10 Laminated sheet 11 Support 12 Easy adhesion layer

Claims (8)

A support made of polyester;
An easy-adhesion layer formed on at least one surface of the support,
The laminated sheet for optics, wherein the easy-adhesion layer contains two types of binders, a polyurethane resin having a glass transition point of 30 ° C or higher and an acrylic resin having a glass transition point of 30 ° C or higher, and a carbodiimide-based crosslinking agent.   The optically laminated sheet according to claim 1, wherein the easy adhesion layer is provided after the support is biaxially stretched.   The optical laminated sheet according to claim 1 or 2, wherein the weight ratio of the polyurethane resin to the acrylic resin is 95: 5 to 50:50.   The optical laminated sheet according to any one of claims 1 to 3, wherein the easy-adhesion layer has a thickness of 30 nm or more and 200 nm or less.   5. The easy-adhesion layer is formed by applying an aqueous coating solution and drying, and a maximum temperature during drying is in a range of 120 ° C. or higher and 170 ° C. or lower. The laminated sheet for optics as described.   The optically laminated sheet according to any one of claims 1 to 5, wherein the easily adhesive layer contains organic or inorganic fine particles and a slip agent. A biaxial stretching step of biaxially stretching a support made of polyester;
An easy-adhesive layer forming step of forming an easy-adhesive layer by applying an aqueous coating liquid to at least one surface of the support after stretching and drying,
The aqueous coating liquid contains two types of binders, a polyurethane resin having a glass transition point of 30 ° C. or higher and an acrylic resin having a glass transition point of 30 ° C. or higher, and a carbodiimide-based cross-linking agent. Sheet manufacturing method.   The weight ratio of the polyurethane resin and the acrylic resin is 95: 5 to 50:50, and the maximum temperature during drying in the easy-adhesion layer forming step is in a range of 120 ° C. or more and 170 ° C. or less. The manufacturing method of the optical laminated sheet of Claim 7.

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