JP2001246699A - Mold release film for protecting liquid crystal polarizing plate adhesive layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold release film having excellent handleability, a small oligomer precipitate amount, a good transparency and an easy optical inspection. SOLUTION: The mold release film comprises a coating layer and a mold release layer provided on one side surface of a biaxially oriented polyester film. In this case, the coating layer and/or the mold release layer comprise on amino group-containing compound (e.g. H2NC2H4NH-(CH2)3-Si-(OCH3)3). The film satisfies specific conditions of an oligomer amount (OL), a nitrogen content (N), a weight per unit area (Wf), a retardation value (Re) of the biaxially oriented polyester film and a total ray transmittance TL).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a release film, and more particularly, to a liquid crystal display (hereinafter, LC).
D) (which may be abbreviated as D).

[0002]

2. Description of the Related Art Conventionally, a release film based on a polyester film has been used for protecting an adhesive layer of a liquid crystal polarizing plate. However, oligomers deposited on the surface of the release layer at high temperatures cause various problems. Let me.

The oligomer deposited on the surface of the release layer is transferred to the surface of the pressure-sensitive adhesive layer to be bonded, and a polarizing plate with the pressure-sensitive adhesive layer to which the oligomer is adhered is bonded to a glass substrate to produce an LCD. In some cases, problems such as a decrease in the brightness of the obtained LCD may occur.

[0004] In recent years, there has been a tendency to increase the brightness of the display screen for the purpose of improving the visibility of LCDs, and the above problem has become a serious problem. Also, with the speeding up of the manufacturing process to reduce manufacturing costs,
In particular, the drying temperature in the drying step tends to be set higher, and the above-mentioned oligomers are more likely to precipitate.

On the other hand, in an inspection process involving an optical evaluation of the display capability, hue, contrast, and contamination of a liquid crystal polarizing plate, measures are taken to prevent the outflow of defective products by visual observation or by using a magnifying glass. However, due to the optical anisotropy of the polyester film constituting the release film, there is a problem that foreign matters are easily overlooked, so that the release film is once peeled off at the time of inspection, and then reattached after the inspection. Something has been done.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a liquid crystal polarizing plate which has excellent handleability when used for protecting an adhesive layer.
An object of the present invention is to provide a release film having a minimum amount of oligomer precipitation, good transparency, and easy inspection involving optical evaluation.

[0007]

Means for Solving the Problems As a result of intensive studies in view of the above situation, the present inventor has found that the above-mentioned problems can be easily solved by using a release film having a specific structure, and has completed the present invention. I came to.

That is, the gist of the present invention is that the thickness is 9 to 5 mm.
A release film in which a coating layer and a release layer having a residual adhesion rate of 80% or more are sequentially provided on one side of a biaxially stretched polyester film of 0 μm, wherein at least one of the coating layer or the release layer is an amino group. Wherein the release film for protecting the pressure-sensitive adhesive layer of the liquid crystal polarizing plate is characterized by simultaneously satisfying the following formulas (1) to (4).

OL ≦ 3.0 (1) N × Wf ≧ 0.5 (2) 30 ≦ Re ≦ 10000 (3) 80 ≦ TL (4) (OL in the above formula is 180 ° C., 10 ° C.) Amount of oligomer (mg / m ² ) extracted with dimethylformamide from the release layer surface of release film after heat treatment for one minute, N is nitrogen content detected by indophenol blue absorbance method through Kjeldahl decomposition from release film (Ppm), Wf is the weight per unit area of the release film (mg / m ² ), Re
Represents the retardation value (nm) of the biaxially stretched polyester film, and TL represents the total light transmittance (%) of the release film.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail.

In the present invention, the polyester used for the polyester film may be a homopolyester or a copolyester. When the polyester used is a homopolyester, the polyester is obtained by polycondensing an aromatic dicarboxylic acid and an aliphatic glycol. Examples of the aromatic dicarboxylic acid include terephthalic acid, 2,6-naphthalenedicarboxylic acid, and the like,
As the aliphatic glycol, ethylene glycol, diethylene glycol, 1,4-cyclohexanedimethano-
And the like. Typical polyesters include polyethylene terephthalate (PET) and polyethylene-
Examples thereof include 2,6-naphthalenedicarboxylate (PEN).

On the other hand, when the polyester used is a copolyester, a copolymer containing 30 mol% or less of the third component is preferred. As the dicarboxylic acid component of the copolymerized polyester, isophthalic acid, terephthalic acid phthalate, 2,6-naphthalenedicarboxylic acid, adipic acid sebacic acid, and one of oxycarboxylic acids (for example, P-oxybenzoic acid and the like) or Two or more types,
As the glycol component, ethylene glycol, diethylene glycol, propylene glycol, butanediol-
Or one or more of 1,4-cyclohexanedimethanol, neopentyl glycol and the like.

In any case, the polyester referred to in the present invention generally means polyethylene terephthalate having an ethylene terephthalate unit of 80 mol% or more, preferably 90 mol% or more, and polyethylene-2 or 6 having an ethylene-2,6-naphthalate unit. Refers to polyester such as 6-naphthalate.

Particles are usually blended in the polyester film layer constituting the release film of the present invention, mainly for imparting lubricity. The type of particles to be blended is not particularly limited as long as the particles can impart lubricity,
Specific examples include particles of silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, magnesium phosphate silicon oxide, kaolin, aluminum oxide, titanium oxide, and the like.

Further, heat-resistant organic particles described in JP-B-59-5216 and JP-A-59-217755 may be used. Examples of other heat-resistant organic particles include thermosetting urea resin, thermosetting phenol resin,
Thermosetting epoxy resin, benzoguanamine resin and the like can be mentioned. Further, during the polyester production process, precipitated particles in which a part of a metal compound such as a catalyst is precipitated and finely dispersed can be used.

On the other hand, the shape of the particles to be used is not particularly limited, and any of spherical, massive, rod-like, flat, etc. may be used. There is no particular limitation on the hardness, specific gravity, color and the like. These series of particles may be used in combination of two or more as necessary.

The average particle size of the particles used is usually 0.1.
It is in the range of 01 to 3 μm, preferably 0.01 to 1 μm. When the average particle size is less than 0.01 μm, the particles are likely to aggregate and dispersibility may be insufficient.
If it exceeds m, the surface roughness of the film may be too coarse, and a problem may occur when a release layer is provided in a subsequent step.

Further, the content of particles in the polyester film layer is usually 0.1 to 5% by weight, preferably 0.1 to 3% by weight.
% By weight. If the particle content is less than 0.1% by weight, the lubricity of the film may be insufficient, while if it exceeds 5% by weight, the transparency of the polyester film may be insufficient. It may be.

The method for adding particles to the polyester film layer is not particularly limited, and a conventionally known method can be employed. For example, it can be added at any stage of producing the polyester, but preferably, the polycondensation reaction may be advanced after the esterification stage or after the transesterification reaction is completed.

A method of blending a polyester raw material with a slurry of particles dispersed in ethylene glycol or water using a kneading extruder equipped with a vent, or a method of blending dried particles with a polyester raw material using a kneading extruder. The method is performed by a method.

Incidentally, in addition to the above-mentioned particles, conventionally known antioxidants, heat stabilizers, lubricants, dyes, pigments and the like can be added to the polyester film of the present invention, if necessary.

The thickness of the biaxially stretched polyester film constituting the release film in the present invention needs to be 9 to 50 μm, preferably 12 to 40 μm, from the viewpoint of film handling. 9μm film thickness
If it is less than 50 μm, the film handling property will be reduced, while if it exceeds 50 μm, the display performance of the liquid crystal polarizing plate, hue, contrast, optical contamination such as contamination, etc. A defect occurs when performing the inspection.

The biaxially stretched polyester film constituting the release film of the present invention must satisfy the above-mentioned film thickness and further have a retardation value (Re) in the range of 30 to 10,000. .
The Re value is preferably 50 to 5000 nm, more preferably 100 to 2000 nm. Re value is 30 nm
If it is less than 1, the chemical resistance of the film will be reduced. On the other hand, if it exceeds 10,000 nm, depending on the angle (θ3) of the orientation axis of the film, there will be no cross between the polarizing plate and the release film. Since it is in the Nicol state (extinction state), when performing an optical inspection, a problem such as the fact that foreign matter is easily overlooked occurs.

Next, the production example of the biaxially stretched polyester film in the present invention will be specifically described, but it is not limited to the following production example.

That is, it is preferable to use a polyester raw material as described above and cool and solidify a molten sheet extruded from a die with a cooling roll to obtain an unstretched sheet.

In this case, in order to improve the flatness of the sheet, it is preferable to increase the adhesion between the sheet and the rotary cooling drum, and the electrostatic application adhesion method and / or the liquid application adhesion method are preferably employed.

Next, the obtained unstretched sheet is stretched biaxially. First, the unstretched sheet is stretched in one direction by a roll or tenter type stretching machine. The stretching temperature is usually 130 to 170 ° C., and the stretching ratio is usually 2.5 to 7 times, preferably 3.0 to 6 times. Next, stretching is performed in a direction orthogonal to the stretching direction of the first stage. The stretching temperature is usually 130 to 170 ° C., and the stretching ratio is
It is usually 3.0 to 7 times, preferably 3.5 to 6 times. Subsequently, a heat treatment is performed at a temperature of 180 to 270 ° C. under tension or relaxation within 30% to obtain a biaxially oriented film. A so-called coating and stretching method (in-line coating) for treating the film surface during the stretching step can be applied. Although it is not limited to the following, in particular, the coating treatment can be performed before the first-stage stretching is completed and before the second-stage stretching.

In the above stretching, the stretching in one direction is performed by 2
It is also possible to use a method of performing the above steps. In that case,
It is preferable that the stretching is performed so that the stretching ratio in the two directions finally falls within the above range. It is also possible to simultaneously biaxially stretch the unstretched sheet so that the area magnification becomes 10 to 40 times. Further, if necessary, the film may be stretched in the longitudinal and / or transverse directions again before or after the heat treatment.

When a coating layer is applied on a polyester film by the above-mentioned coating and stretching method, coating can be performed simultaneously with stretching, and the thickness of the coating layer can be reduced according to the stretching ratio. A film suitable as a biaxially stretched polyester film can be produced.

The release film of the present invention has a temperature of 180.degree.
Since the amount of oligomers extracted with dimethylformamide from the surface of the release layer after heat treatment for one minute must be suppressed to 3.0 mg / m ² or less, at least one of the coating layer and the release layer contains a compound having an amino group. There is a need.

Specific examples of the compound having an amino group include N-β (aminoethyl) γ-aminotripropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltriethoxysilane, N-β (amino ethyl)
Examples include, but are not limited to, γ-aminopropylmethyldimethoxysilane, γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, and the like.

Among them, it is particularly preferable to use a silane compound represented by the following general formula (A) because the effect of preventing oligomer precipitation is further improved.

Y— (CH ₂ ) ₃ —Si— (X) ₃ (A) (In the above formula, Y is a —NH ₂ group or —NHCH ₂ CH ₂ N
H ₂ group, X is also represents a -OCH ₃ group or -OCH ₂ CH ₃ groups), the coating layer and preferably between coated on a polyester film by the above-mentioned coating stretching method (in-line coating method).

In the coating layer constituting the release film of the present invention, a binder polymer may be used in combination with the above-mentioned compound having an amino group as long as the gist of the present invention is not impaired.

Specific examples of the binder polymer used in combination include polyacrylamide, polyalkylene glycol, polyalkyleneimine, methylcellulose, hydroxycellulose, starch, polyurethane, polyester, polyacrylate, and chlorine-based polymers (polyvinyl chloride, vinyl chloride acetate). Vinyl copolymer), polyolefin and the like. Among them, when the coating layer is applied by a coating and stretching method, nonionic, cationic, amphoteric organic polymers that can be used as an aqueous solution or aqueous dispersion, and among them, polyurethane, polyester When polyacrylate is used, the adhesion to the overcoat layer becomes good. These polymers are provided with hydrophilicity and can be dispersed in water by copolymerizing nonionic, cationic or amphoteric hydrophilic components as one component of the monomers.

The coating layer may be used in combination with a crosslinking agent. Specific examples thereof include methylolated or alkylolated urea-based, melamine-based, guanamine-based, acrylamide-based, polyamide-based compounds, epoxy compounds, and aziridines. Compounds, block polyisocyanates, titanium coupling agents, zircoaluminate coupling agents, and the like. These crosslinking components may be pre-bonded to the binder polymer.

For the purpose of improving the fixability and slipperiness of the coating layer, inorganic particles may be incorporated in the coating layer. Specific examples include silica, alumina, kaolin, calcium carbonate, titanium oxide, barium salt and the like. Is mentioned. If necessary, an antifoaming agent, a coating improver, a thickener, an organic lubricant, an organic polymer particle, an antioxidant, an ultraviolet absorber, a foaming agent, a dye, and the like may be added.

In the present invention, the coating amount of the coating layer is 0.1.
01~1g / m ^2, more preferably in the range of 0.03~0.5g / m ^2. When the coating amount is less than 0.01 g / m ² , the uniformity of the coating thickness may be insufficient.
In the case of application exceeding 1 g / m ² , a problem may occur due to a decrease in slipperiness.

In the present invention, a method of providing a coating layer on a polyester film may be performed by a bar coating method, a gravure coating method, or the like, as in the case of coating a release layer described later.
A conventionally known coating method can be used.

The release layer constituting the release film of the present invention is not particularly limited as long as it contains a material having a releasing property. It is preferable to use it because the releasability is improved.
A type having a curable silicone resin as a main component or a modified silicone type obtained by graft polymerization with an organic resin such as a urethane resin, an epoxy resin, or an alkyd resin may be used.

As the type of the curable silicone resin, any of a curing reaction type such as an addition type, a condensation type, an ultraviolet curable type, an electron beam curable type, and a solventless type can be used.

Specific examples include KS-774, KS-775, KS-778, and KS-7 manufactured by Shin-Etsu Chemical Co., Ltd.
79H, KS-847H, KS-856, X-62-2
422, X-62-2461, X-62-5039, X
-62-5040, DKQ3-202, DKQ3-203, DKQ3-20 manufactured by Dow Corning Asia Ltd.
4, DKQ3-205, DKQ3-210, YSR-3022, TPR-6700, T
PR-6720, TPR-6721, Dow Corning Toray SD7220, SD7226, SD72
29 and the like. Further, a release control agent may be used in combination to adjust the release property of the release layer. Also,
As described above, a silane compound having an amino group may be added to the release layer.

In the present invention, a conventionally known coating method such as reverse roll coating, gravure coating, bar coating, or doctor blade coating can be used as a method for applying a release layer to the biaxially stretched polyester film.

The coating amount of the release layer is 0.01 from the viewpoint of coatability.
To 1 g / m ² , and more preferably 0.03 to 0.5 g / m ² . If the coating amount of the release layer is less than 0.01 g / m ² , stability may be lacked from the viewpoint of coatability, and it may be difficult to obtain a uniform coating film. On the other hand, when the thickness exceeds 1 g / m ² , the adhesiveness of the release layer itself, the curability, and the like may be reduced.

In the release film of the present invention, a coating layer such as an oligomer precipitation preventing layer, an adhesive layer, and an antistatic layer may be provided on the surface where the release layer is not provided, if necessary.
The biaxially stretched polyester film may be subjected to a surface treatment such as a corona treatment and a plasma treatment.

The release film of the present invention has a temperature of 180.degree.
The oligomer amount (OL) extracted with dimethylformamide from the surface of the release layer after heat treatment for 3.0 minutes is 3.0 mg / m 2
Must be ² or less. When OL exceeds 3.0 mg / m ² , the amount of oligomers on the surface of the release layer of the release film increases, and in the liquid crystal polarizing plate pressure-sensitive adhesive layer protective application,
Problems such as a decrease in the transparency of the partner pressure-sensitive adhesive layer to be bonded and a decrease in the adhesive force of the pressure-sensitive adhesive layer occur.

Further, the nitrogen content per unit area (N × Wf) in the release film of the present invention is 0.5 mg /
m ² or more, preferably 2.0 mg / m ²
More preferably, it is 4.0 mg / m ² or more.
When N × Wf is less than 0.5 mg / m ² , the obtained release film is poor in oligomer precipitation preventing effect.

The above N is the nitrogen content (ppm) detected from the release film through Kjeldahl decomposition by the indophenol blue absorbance method, and Wf is the weight per unit area (mg / m ² ) of the release film. ).

The total light transmittance (T) of the release film of the present invention
L) needs to be 80% or more for use. If the TL is less than 80%, the transparency becomes insufficient, and in the inspection process involving optical evaluation, a problem such as the inconvenience of foreign matter being easily overlooked occurs.

The residual adhesive ratio of the release film of the present invention is preferably 80% or more because it suppresses transfer or transfer of silicone to the surface of the pressure-sensitive adhesive layer to be bonded or to the surface of the transport roll in the manufacturing process. It is necessary, and preferably 90% or more.

When the residual adhesion ratio is less than 80%, problems such as the transfer of the silicone transfer component to the roll surface of the transport roll and the decrease in the adhesive force of the pressure-sensitive adhesive layer in contact with the release surface during the production process are caused. Will occur.

[0052]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist. In the examples and comparative examples, “parts” means “parts by weight”. The measuring method used in the present invention is as follows. (1) Measurement of Intrinsic Viscosity of Polyester 1 g of polyester from which other polymer components and pigments incompatible with polyester were removed was precisely weighed, and phenol / tetrachloroethane = 50/50 (weight ratio) mixed solvent 10
0 ml was added and dissolved, and the measurement was performed at 30 ° C. (2) Measurement of average particle size (d ₅₀ : μm) 50% of integrated (weight basis) in equivalent spherical distribution measured using a centrifugal sedimentation type particle size distribution measuring device (SA-CP3 manufactured by Shimadzu Corporation). Was taken as the average particle size. (3) Measurement of the thickness of the biaxially stretched polyester film Muimetron “4M-100PT” manufactured by Citizen Watch Co., Ltd.
The film thickness was measured using "YPE V-2". (4) Measurement of Retardation Value (Re) of Biaxially Stretched Polyester Film Using an Abbe refractometer manufactured by Atago Optical Co., Ltd., using the release layer surface side as the measurement surface, the film surface of the base film constituting the release film was measured. The maximum value nγ of the refractive index and the refractive index nβ in the direction orthogonal thereto are measured, and the difference (nγ
−nβ) was calculated. The difference (nγ−nβ) was multiplied by the thickness of the film whose refractive index was measured to obtain a retardation value. (5) Measurement of the amount of oligomer (OL) extracted with dimethylformamide from the surface of the release layer of the release film The release film after heat treatment (180 ° C., 10 minutes) was opened at the top, and the area of the bottom was 250 cm. folded so as to be ^2, to create a square box. When a coating layer is provided, the coating layer face is on the inside.

Next, in the box created by the above method,
After 10 ml of DMF (dimethylformamide) is added and left for 3 minutes, DMF is recovered. The recovered DMF is supplied to a liquid chromatography (Shimadzu LC-7A) for DM
The amount of oligomer in F was determined, and this value was divided by the area of the film in contact with DMF to obtain the amount of oligomer on the film surface (m
g / m ² ).

The amount of oligomer in DMF was determined from the peak area ratio between the peak area of the standard sample and the peak area of the measurement sample (absolute calibration curve method).

To prepare a standard sample, an oligomer (cyclic trimer) fractionated in advance was accurately weighed, and the accurately weighed DM
F. The concentration of the standard sample is 0.001 to
A range of 0.01 mg / ml is preferred. The conditions of the liquid chromatography were as follows.

Mobile phase A: acetonitrile Mobile phase B: 2% acetic acid aqueous solution Column: MCI GEL ODS manufactured by Mitsubishi Chemical Corporation
1HU Column temperature: 40 ° C. Flow rate: 1 ml / min Detection wavelength: 254 nm (6) Nitrogen content per unit area of release film (N ×
Calculation method of Wf) * Measurement method of nitrogen content (N) in release film 500 mg of a sample sample was accurately weighed, and concentrated sulfuric acid 2 g,
20 ml of copper sulfate and 5 g of potassium sulfate are added, followed by thermal decomposition (Kjeldahl decomposition). That is, the mixture is heated with a gas burner and heated for 30 minutes after the liquid becomes green and transparent. After dissolution, the mixture is allowed to cool, 300 ml of pure water is added, and NaOH is added to distill off NH ₃ generated until it becomes alkaline. Next, after dispensing the sample in a 250 ml constant volume, the nitrogen content in the sample was measured by the indophenol blue absorbance method (measuring wavelength: 640 nm).

The value obtained by subtracting the nitrogen content detected in the presence of the polyester film without the release layer and the coating layer from the average value measured five times in the above procedure is used as the value in the release film. Nitrogen content (N: ppm)
And * Method of calculating weight per unit area of release film (Wf) The weight of a release film having a size of 10 cm square was measured, and the weight per unit area (Wf: mg / m ² ) was calculated.

The (N × Wf) value was calculated using the N value and Wf value obtained by each of the above methods. (7) Measurement of total light transmittance (TL) of release film According to JIS-K-7105, the total light transmittance of the release film was measured using an integrating sphere turbidimeter “NDH-300A” manufactured by Nippon Denshoku Industries Co., Ltd. The rate (%) was measured. (8) Measurement of Residual Adhesion Rate of Release Film Residual Adhesion: Nitto Denko No. The 31B pressure-sensitive adhesive tape is pressed back and forth with a 2 kg rubber roller once, and heat-treated at 100 ° C. × 1 hour. Next, the sample film was peeled off from the crimped sample,
o. The adhesive strength of the 31B adhesive tape is measured according to the method of JIS-C-2107 (adhesive strength to stainless steel plate, 180 ° peeling method). This is defined as the residual adhesive force.

Basic adhesive strength: An adhesive tape is pressure-bonded to a stainless steel plate according to JIS-C-2107 using the same tape (No. 31B) as in the case of the residual adhesive strength, and the measurement is performed in the same manner. The value at this time is defined as the basic adhesive strength. Using these measured values, the residual adhesion rate is determined based on the following equation.

Residual adhesion rate (%) = Residual adhesive strength ÷ Basic adhesive strength × 100 The measurement is performed at 20 ± 2 ° C. and 65 ± 5% RH. (9) Measurement of release force (F) of release film A double-sided adhesive tape (Nitto Denko “N
o. 502 "), 50mm x 300
After cutting to a size of mm, the peeling force after leaving for 1 hour is measured. As the peeling force, a 180 ° peeling was performed under a tensile speed of 300 mm / min using a tensile tester (“Intesco Model 2001” manufactured by Intesco Corporation). (10) Evaluation of handleability of release film The handleability at the time of attaching the release film to a polarizing plate having an adhesive layer was evaluated according to the following criteria. << Judgment Criteria >> Good: Practical problem level Poor: Practical problem level (11) Evaluation of quenching state of release film The release film and the polarizing plate are bonded via the adhesive layer to which foreign matter is adhered. In the laminated body thus bonded, the presence or absence of an extinction state when viewed through light from the release film side was observed. (12) Evaluation of ease of inspection of release film In a laminate in which the release film and the polarizing plate are bonded via the pressure-sensitive adhesive layer to which the foreign material is adhered, foreign matter when viewed through light from the release film side is considered. The visibility was evaluated according to the following criteria. << Judgment Criteria >> Good… Inspection possible (no problem in practical use) Slightly poor… In some cases, inspection is difficult (level in which there is a problem in practical use) Defective… Not inspectable (level in which there is a problem in practical use) Used in Examples and Comparative Examples The production conditions of the polyesters were as follows. <Production of polyester> Production example 1 (polyethylene terephthalate A1) 100 parts of dimethyl terephthalate, 60 parts of ethylene glycol and 0.09 part of magnesium acetate tetrahydrate were placed in a reactor, heated and heated, and methanol was distilled off.
The transesterification reaction was performed, and the temperature was raised to 230 ° C. over 4 hours from the start of the reaction, and the transesterification reaction was substantially completed. Then 0.04 parts of ethylene glycol slurry ethyl acid phosphate, 0.03 part of antimony trioxide
Parts, 0.1 part of silica particles having an average particle size of 0.1.54 μm was added, and the temperature was increased to 280 ° C. and the pressure was increased to 15 m in 100 minutes.
mHg, and thereafter the pressure was gradually reduced to finally 0.3 mmHg. Four hours later, the inside of the system was returned to normal pressure,
Polyethylene terephthalate A1 having an intrinsic viscosity of 0.61 was obtained.

Production Example 2 (Polyethylene terephthalate A)
2) Polyethylene terephthalate was prepared in the same manner as in Production Example 1 except that 1 part of titanium oxide particles having an average particle diameter of 0.27 μm was added instead of adding 0.1 parts of silica particles having an average particle diameter of 1.54 μm. A2 was obtained. <Production of Biaxially Stretched Polyester Film> Production Example 3 (PET Film F1) The polyethylene terephthalate A1 produced in Production Example 1 was dried at 180 ° C. for 4 hours in an inert gas atmosphere and melted at 290 ° C. by a melt extruder. Then, the mixture was extruded from a die and cooled and solidified on a cooling roll having a surface temperature set to 40 ° C. using an electrostatic application contact method to obtain an unstretched sheet. The obtained sheet was stretched 3.5 times in the longitudinal direction at 85 ° C. Next, after applying a coating agent having the following composition, the film was guided to a tenter and stretched 3.7 times in the transverse direction at 100 ° C.
And heat-set at ℃, and the thickness of the coating layer after drying is 0.03
A PET film F1 coated with a 38 μm thick coating layer having a thickness of 38 μm was obtained.

Examples of the compounds constituting the coating layer are as follows. (Composition of coating layer) N-β (aminoethyl) γ-aminopropyltrimethoxysilane 90% by weight PVA resin 10% by weight The solid content of the coating solution was 2% by weight. Examples of compounds constituting the coating layer are as follows. N-β (aminoethyl) γ-aminopropyltrimethoxysilane In the preparation of the H ₂ NC ₂ H ₄ NHC ₃ H ₆ Si (OCH ₃ ) ₃ coating solution, pure water was used as a diluent for concentration adjustment. N-β (aminoethyl) γ-aminopropyltriethoxysilane In the preparation of the H ₂ NC ₂ H ₄ NHC ₃ H ₆ Si (OC ₂ H ₅ ) ₃ coating solution, pure water was used as a diluent for concentration adjustment. In adjusting the γ-aminopropyltrimethoxysilane H ₂ NC ₃ H ₆ Si (OC ₂ H ₆ ) ₃ coating solution, pure water was used as a diluent for concentration adjustment. N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane In the preparation of the H ₂ NC ₂ H ₄ NHC ₃ H ₆ Si (OCH ₃ ) ₂ CH ₃ coating solution, pure water was used as a diluent for concentration adjustment. N-phenyl-γ-aminopropyltrimethoxysilane In the preparation of the C ₆ H ₅ NHC ₃ H ₆ Si (OCH ₃ ) ₃ coating solution, pure water was used as a diluent for concentration adjustment. γ-glycidoxypropyltriethoxysilane

[0063]

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PVA resin Polyvinyl alcohol having a degree of saponification of 88 mol% and a degree of polymerization of 500 Production Example 4 (PET film F2) to Production example 8 (PET film F6) In Production example 3, the coating composition was as shown in Table 1 below. PET films F2 to F6 were obtained in the same manner as in Production Example 3 except that the coating composition was changed as shown.

The properties of these PET films are as shown in Table 1 below.

Production Example 9 (PET film F7) Production Example 3 was the same as Production Example 3 except that no coating layer was applied.
In the same manner as in the above, a PET film F7 was obtained. Table 1 shows the properties of the obtained film.

Production Example 10 (PET film F8) In the same manner as in Production Example 3, a film having a thickness of 25
A μm PET film F8 was obtained. Table 1 shows the properties of the obtained film.

Production Example 11 (PET film F9) In the same manner as in Production Example 3, a 6 μm thick
m of PET film F9 was obtained. Table 1 shows the properties of the obtained film.

Production Example 12 (PET Film F10) A PET film F10 was obtained in the same manner as in Production Example 3 except that polyethylene terephthalate A2 was used instead of polyethylene terephthalate A1.
Table 1 shows the properties of the obtained film.

Production Example 13 (PET film F11) A film having a thickness of 75
A μm PET film F11 was obtained. Table 1 shows the properties of the obtained film.

Production Example 14 (PET Film F12) The polyethylene terephthalate A1 produced in Production Example 1 was dried at 180 ° C. in an inert gas atmosphere for 4 hours, melted at 290 ° C. by a melt extruder, and extruded from a die. The unstretched sheet was obtained by cooling and solidifying on a cooling roll having a surface temperature set to 40 ° C. by using an applied contact method.

Next, a coating agent having the same composition as in Production Example 3 was applied to the obtained unstretched sheet, and the film was guided to a tenter and dried at 80 ° C., and the thickness of the dried coating layer was 0.1 mm. A PET film F12 having a thickness of 50 μm and a thickness of 03 μm was obtained. Table 1 shows the properties of the obtained film.

Production Example 15 (PET Film F13) In Production Example 3, the longitudinal stretching ratio was set to 5.0 times,
Produced in the same manner as in Production Example 3 except that the film is not stretched in the lateral direction, and the thickness of the coating layer after drying is 0.03 μm.
A PET film F13 having a thickness of 50 μm was obtained. Table 1 shows the properties of the obtained film.

Production Example 16 (PET Film F14) A 38 μm-thick PET film F14 coated with an application layer was produced in the same manner as in Production Example 3 except that the composition of the coating layer was changed to the following composition. Obtained. Table 1 shows the properties of the obtained film. (Composition of coating layer) γ-aminopropyltrimethoxysilane 45% by weight PVA resin 55% by weight The solid content of the coating solution was 2% by weight.

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[Table 1]

In Table 1 above, Re in Production Example 12 is indicated by "-", meaning that measurement is impossible.

Example 1 A release layer having the following composition was further applied on the coating layer of the PET film F1 obtained in Production Example 3 at a coating amount of 0.1 g / m 2.
² (after drying) to obtain a release film. << Release Agent Composition >> Curable Silicone Resin (KS-847H: Shin-Etsu Chemical Co., Ltd.) 100 parts Curing Agent (PL-50T: Shin-Etsu Chemical Co., Ltd.) 1 part MEK / toluene mixed solvent 1500 parts Example 2 In Example 1, PET was used. PE instead of film F1
A release film was obtained in the same manner as in Example 1 except that the T film F2 was used.

Example 3 In Example 1, PE film was replaced with PE film.
A release film was obtained in the same manner as in Example 1 except that the T film F3 was used.

Example 4 In Example 1, PE film was replaced by PE film.
A release film was obtained in the same manner as in Example 1 except that the T film F4 was used.

Example 5 In Example 1, PE film was used instead of PET film F1.
Using a T film F4, a release film was obtained in the same manner as in Example 1 except that the composition of the release agent was changed to the following release agent. << Release Agent Composition >> Curable Silicone Resin (KS-723A: Shin-Etsu Chemical) 100 parts Curable Silicone Resin (KS-723B: Shin-Etsu Chemical) 25 parts Curing Agent (PS-3: Shin-Etsu Chemical) 5 parts MEK / Toluene mixed solvent 1500 parts Example 6 In Example 1, PE film was used instead of the PET film F1.
A release film was obtained in the same manner as in Example 1 except that the T film F8 was used.

Example 7 In Example 1, PE film was replaced by PE film.
A release film was obtained in the same manner as in Example 1 except that the T film F5 was used.

Example 8 In Example 1, PE film was used instead of PET film F1.
A release film was obtained in the same manner as in Example 1 except that the T film F14 was used.

Comparative Example 1 In Example 1, PE film was used instead of the PET film F1.
Except for using the T film F6, in the same manner as in Example 1,
A release film was obtained.

Comparative Example 2 In Example 1, PE film was used instead of the PET film F1.
A release film was obtained in the same manner as in Example 1 except that the T film F13 was used.

Comparative Example 3 In Example 1, PE film was used instead of the PET film F1.
Except for using the T film F7, in the same manner as in Example 1,
A release film was obtained.

Comparative Example 4 In Example 1, PE film was used instead of PET film F1.
Except for using the T film F9, in the same manner as in Example 1,
A release film was obtained. However, the entire film was wrinkled, which was at a practically problematic level.

Comparative Example 5 In Example 1, PE film was used instead of the PET film F1.
A release film was obtained in the same manner as in Example 1 except that the T film F10 was used.

Comparative Example 6 In Example 1, PE film was used instead of the PET film F1.
A release film was obtained in the same manner as in Example 1 except that the T film F11 was used.

Comparative Example 7 In Example 1, PE film was used instead of the PET film F1.
A release film was obtained in the same manner as in Example 1 except that the T film F12 was used. The obtained release film had a poor release surface, and was at a practically problematic level.

Comparative Example 8 A release film was obtained in the same manner as in Example 1, except that the composition of the release agent was changed to the following release agent. << Release Agent Composition >> Curable Silicone Resin (FSXK-2560: manufactured by Tow Corning Asia) 35 parts Curing Agent (FSK-1638: Tow Corning Asia) 2 parts MEK / toluene mixed solvent 1400 parts Comparative Example 9 Production Example Using the PET film F7 obtained in 9 except that the composition of the release agent was changed to the following release agent, it was produced in the same manner as in Example 1 to obtain a release film. << Releasing agent composition >> Curable silicone resin (KS-847H: Shin-Etsu Chemical Co., Ltd.) 100 parts Curing agent (PL-50T: Shin-Etsu Chemical Co., Ltd.) 1 part Amino-modified silicone oil (Shin-Etsu Chemical Co., Ltd .: KF-859) 3 parts MEK / Toluene mixed solvent 1500 parts The characteristics of the release films obtained in the above Examples and Comparative Examples are shown in Tables 2 and 3 below.

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[Table 2]

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[Table 3]

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The release film of the present invention has excellent handleability when used for protecting the pressure-sensitive adhesive layer of a liquid crystal polarizing plate, has a minimum amount of precipitated oligomers, has excellent transparency, and is inspected with optical evaluation. And its industrial value is extremely high.

Continued on the front page F-term (reference) 2H091 FA08X FA08Z FC09 FD15 GA17 4F100 AH02B AH03B AH06B AK41A AK52B BA02 BA25A CA02B EH46B EJ38A GB90 JB08 JB12B JK06B JL14B JN01 YY00 YY00J35B01B08A

Claims (3)

[Claims] 1. A release film comprising a biaxially stretched polyester film having a thickness of 9 to 50 μm and a coating layer provided on one side thereof and a release layer having a residual adhesion rate of 80% or more.
At least one of the coating layer and the release layer contains a compound having an amino group, and simultaneously satisfies the following formulas (1) to (4): a release film for protecting an adhesive layer of a liquid crystal polarizing plate. OL ≦ 3.0 (1) N × Wf ≧ 0.5 (2) 30 ≦ Re ≦ 10000 (3) 80 ≦ TL (4) (in the above formula, OL is at 180 ° C. for 10 minutes after heat treatment. The amount of oligomers (mg / m ² ) extracted from the release layer surface of the release film by dimethylformamide, and N is the nitrogen content (ppm) detected from the release film by Kjeldahl decomposition and indophenol blue absorbance method , Wf are the weight per unit area of the release film (mg / m ² ), Re
Represents the retardation value (nm) of the biaxially stretched polyester film, and TL represents the total light transmittance (%) of the release film.) 2. The release film for protecting a pressure-sensitive adhesive layer of a liquid crystal polarizing plate according to claim 1, wherein the compound having an amino group is represented by the following general formula (A). Y— (CH ₂ ) ₃ —Si— (X) ₃ (A) (where Y is an NH ₂ group or —NHCH ₂ CH ₂ NH ₂
Group, X represents a -OCH ₃ group or -OCH ₂ CH ₃ groups) 3. The release film for protecting an adhesive layer of a liquid crystal polarizing plate according to claim 1, wherein the release layer contains a curable silicone resin.