JPH10278203A - Release film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide excellent releasability, cushionability and electrifiability by simultaneously satisfying specific formulae in a release film having a release layer at least on one surface of a polyester film containing fine bubble. SOLUTION: The release film comprises a release layer on at least one surface of a polyester film containing fine bubble. The bubble contained in the polyester film is formed by various means and formed of thermoplastic resin substantially non-compatible with polyester. Thus, the polyester film can obtain cushionability. The release film simultaneously satisfies formulae 1 to 4 (where D indicates an apparent density (g/cm<2> ) of the release film, F indicates release force (gf/5 mm width) of the release film, F indicates surface specific resistance (Ω) of either one surface of the release film, and OD indicates concealability of the release film).

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 card, a label, a printing, an adhesive,
It relates to various release films such as ceramic molding.

[0002]

2. Description of the Related Art Conventionally, release films based on polyester films have been used for various types of release, such as for cards, labels, printing, adhesives, and ceramic molding. When concealing properties are required for printing, printing or the like, a release film having a white polyester film as a base material is usually used. When a higher level of sharpness during printing is required, a release film having cushioning properties is required as a printing substrate. Another problem with the use of a release film based on a polyester film is that once static electricity is generated during the processing process, the release film itself continues processing while holding the static electricity. Problems such as poor peeling or uneven coating may occur, and the solution is desired. As described above, at present, there is an urgent need for a release film having adequate release properties, cushioning properties, and antistatic properties suitable for various types of release.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a release film having excellent release properties, cushioning properties and antistatic properties.

[0004]

Means for Solving the Problems In view of the above-mentioned circumstances, the present inventors have found that a release film having a specific structure is excellent in release properties, cushioning properties, and antistatic properties. It was completed. That is, the gist of the present invention is a release film having a release layer on at least one surface of a polyester film containing fine bubbles, wherein the release film satisfies the following formulas (1) to (4) simultaneously. Exist in the mold film.

[0005]

0.40 ≦ D ≦ 1.30 (1) 5 ≦ F ≦ 1500 (2) R ≦ 10 ¹³ (3) 0.3 ≦ OD (4) (In the above formula, D is Apparent density of release film (g / c
m ³ ), F is the peeling force of the release film (gf / 50 mm)
Width), R is the surface specific resistance (Ω) of any one surface of the release film, and OD represents the degree of concealment of the release film.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The polyester film constituting the release film of the present invention is characterized by containing fine bubbles. The polyester used is a polyester obtained by polycondensing an aromatic dicarboxylic acid and an aliphatic glycol, and the aromatic dicarboxylic acid includes terephthalic acid,
Examples of 2,6-naphthalenedicarboxylic acid include aliphatic glycols such as ethylene glycol, diethylene glycol, and 1,4-cyclohexanedimethanol. Representative polyesters include polyethylene terephthalate (PET), polyethylene-2,
6-naphthalenedicarboxylate (PEN) and the like are exemplified. The polyester may be a copolymer containing a third component. When the copolymerized polyester,
As the dicarboxylic acid component, isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid,
One or more of adipic acid, sebacic acid, and oxycarboxylic acid (for example, P-oxybenzoic acid and the like) are included, and the glycol component includes ethylene glycol, diethylene glycol, propylene glycol, butanediol, and 1,4-cyclohexane. Dimethanol,
One or more of neopentyl glycol and the like can be mentioned.

The fine bubbles contained in the polyester film of the present invention are formed by various means, but are preferably formed of a thermoplastic resin substantially incompatible with polyester. By containing fine bubbles, the polyester film can have cushioning properties. Specific examples of the thermoplastic resin substantially incompatible with polyester include polyolefin such as polyethylene, polypropylene, polymethylpentene, and polymethylbutene, as well as polystyrene, polycarbonate, and polyphenylene sulfide. Among them, polypropylene is preferable in terms of productivity.

The above polypropylene is preferably a crystalline polypropylene homopolymer having 95 mol% or more, preferably 98 mol% or more of propylene units.
In the case of amorphous polypropylene, polypropylene may bleed out on the surface of the unstretched polyester sheet in the film production process, and the production equipment may be soiled. In the case of polypropylene in which ethylene units other than propylene units are copolymerized, for example, in an amount exceeding 5 mol%, the formation of closed cells may be insufficient.

The polypropylene preferably has a melt flow index (MFI) of 0.5 to 30 g / min, preferably 1.0 to 15 g / min. MFI is 0.
If it is less than 5 g / min, the generated bubbles may be too large, while if it exceeds 30 g / min,
Controlling the density can be difficult. The content of the thermoplastic resin substantially incompatible with the polyester contained in the polyester layer in the present invention is usually 5 to 45% by weight,
Preferably it is 10 to 35% by weight, more preferably 15 to 35% by weight.
It is in the range of 25% by weight. If the content is less than 5% by weight, the amount of air bubbles formed in the polyester film is small, so that the cushioning property may be insufficient. It is easily broken, and film formation may be difficult.

In the present invention, when a thermoplastic resin which is substantially incompatible with the polyester is incorporated into the polyester layer, the purpose is to control the size of bubbles formed in the polyester film. It is preferable to use a surfactant in combination. Examples of the type of the surfactant include anionic, cationic, amphoteric, and nonionic surfactants. Among them, nonionic surfactants, particularly silicone surfactants, are preferred. Specific examples of the silicone-based surfactant include an organopolysiloxane-polyoxyalkylene copolymer and an alkenylsiloxane having a polyoxyalkylene side chain. The content of the surfactant in the polyester layer is not particularly limited, but may be 0.001 to 1.0.
0% by weight, and more preferably 0.01 to 0.5% by weight. When the content of the surfactant is less than 0.001% by weight, the foam-controlling effect may be insufficient. On the other hand, when the content is more than 1.0% by weight, there is a problem in the film production process, particularly in the extrusion process. May occur.

The polyester layer in the present invention preferably contains particles for the purpose of mainly providing concealing properties. The type of particles to be contained is not particularly limited as long as it is a particle capable of imparting concealing properties, but white particles are preferable, and titanium dioxide and barium sulfate are more preferable. The average particle size of the particles is 0.01 to 5 μm, and more preferably 0.1 to 5 μm.
The range of 01 to 3 μm is good. The average particle size of the particles is 0.01
If it is less than μm, the particles are likely to agglomerate and the dispersibility may be insufficient.On the other hand, if it exceeds 5 μm, the surface roughness of the film may be too coarse, and the release layer may be formed in a later step. In some cases, problems may occur when the layers are stacked.

Further, the particle content in the polyester layer is as follows:
The range is preferably 0.5 to 20% by weight, more preferably 1.0 to 20% by weight. When the particle content is less than 0.5% by weight,
In some cases, the hiding power is insufficient. On the other hand, when it is added in excess of 20% by weight, the surface roughness of the polyester film may be too coarse. The method for adding particles to the polyester 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 slurry of particles dispersed in ethylene glycol or water or the like with a polyester raw material using a kneading extruder with a vent, or a method of blending dried particles with a polyester raw material using a kneading extruder. And so on.

In addition to the above-mentioned particles, the object is to improve the concealing property.
And a fluorescent whitening agent may be used in combination. In the present invention,
The fluorescent brightener content in the ester layer is 0 to 0.30 weight
% Is preferred. Apparent release film of the present invention
The density (D) is 0.40 to 1.30 g / cm ^ThreeIn the range
is there. When the apparent density of the release film is less than 0.40
If the release film has insufficient mechanical strength,
On the other hand, if it exceeds 1.30, cushion the release film.
Performance is impaired. Release force of release film of the present invention
(F) is in the range of 5 to 1500 gf / 50 mm width.
You. Release force of release film is less than 5gf / 50mm width
If the peeling force is too light,
Failure occurs, while exceeding 1500gf / 50mm width
If the peeling force is too large,
Condition occurs.

The surface specific resistance (R) of one of the surfaces of the release film of the present invention is 10 ¹³ Ω or less. If the surface resistivity of any one side of the release film exceeds 10 ¹³ Ω, the antistatic effect is insufficient. The concealing degree (OD) of the release film of the present invention is 0.3 or more, preferably 0.5 or more. If the hiding degree is less than 0.3, the hiding properties are insufficient. In addition, known antioxidants, heat stabilizers, lubricants, dyes, pigments, and the like can be added to the polyester film of the present invention, if necessary, in addition to the particles and the fluorescent whitening agent. The thickness of the polyester film in the present invention is not particularly limited as long as it can be formed into a film, but usually 12 to 350 μm,
Preferably, the range is 38 to 250 μm.

Next, the production example of the polyester film in the present invention will be specifically described, but it is not limited to the following production example. That is, a method in which an unstretched sheet is obtained by cooling and solidifying a molten sheet extruded from a die using a cooling roll using the polyester raw material described above is preferable. 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 in one direction by a roll or a tenter type stretching machine. The stretching temperature is usually 70 to 120 ° C, preferably 80 to 110 ° C, and the stretching ratio is usually 2.5
７7 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 70 to 130 ° C, preferably 80 to 120 ° C, and the stretching ratio is usually 3.0.
7 times, preferably 3.5 times to 6 times. After stretching, 17
Heat treatment is performed at a temperature of 0 to 250 ° C. under tension or relaxation within 30% to obtain a biaxially oriented film. A so-called coating 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-mentioned stretching, 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-described coating and stretching method, the coating can be performed simultaneously with the stretching, and the thickness of the coating layer can be reduced according to the stretching ratio. Suitable films can be produced relatively inexpensively.

In the present invention, as a method for imparting antistatic properties to the release film, there are a “deposition method” in which a conductive material such as chromium vapor is deposited on a polyester film, and “kneading” in which an antistatic agent is kneaded into the polyester film. Known methods such as a method of incorporating an antistatic agent in a release layer, and a method of applying a coating layer containing an antistatic agent to a polyester film can be used, and are particularly limited. However, it is necessary that the surface specific resistance of any one side of the release film be 10 ¹³ Ω or less. Among the above methods, a method of applying a coating layer containing an antistatic agent to a polyester film is preferable, and more preferably, the method is applied on a polyester film by the above-mentioned coating and stretching method (in-line coating method). Is good.

Examples of the antistatic agent contained in the above-mentioned coating layer include quaternary ammonium salt-containing compounds such as cationic compounds, phosphoric acid ester salts, and organic metal salts of organic sulfonic acids. It is preferable to use a polymer containing either an ionized nitrogen element or a pyrrolidium ring in the main chain, because the antistatic property is further improved. As an example of a polymer containing an ionized nitrogen element in the main chain, an ionene polymer can be given. As a specific example, Japanese Patent Publication No. 53-2337
No. 7, JP-B-54-10039, JP-A-47
JP-A-34581, JP-A-56-76451,
JP-A-58-93710, JP-A-61-1875
No. 0, JP-A-63-68687 and the like.

For details, see ALAN D. WILSON an
d HAVARD J .; PROSSER (Ed.) DE
VELOMENTS IN IONIC POLYME
RS-2 ELSEVIER APPLIED SCIE
NCE PUBLISHER, 1986), IONE
NE POLYMERS :, PROPERTIES AN
It is described in DAPPLICATIONS. on the other hand,
Examples of the polymer containing a pyrrolidium ring in the main chain include polymers having the following structures (A) and (B).

[0021]

Embedded image In the above formula, R ¹ and R ² are usually an alkyl group or a phenyl group, and R ¹ and R ² may be the same group, or may be a type in which the alkyl group or the phenyl group is substituted with a functional group shown below. .

As an example of a substitutable functional group,
Hydroxy, amide, lower alkoxy, phenoxy, naphthoxy, cyano, thiophenoxy, cycloalkyl,
Triammonium lower alkyl and nitro groups can be substituted only on the alkyl group, and halogen groups can be substituted only on the phenyl group. R ¹ and R ² may be chemically bonded to each other, and include — (CH ₂ ) _n — (n is an integer of 2 to 5) and —CH
= CH-CH = CH-, -CH = CH-CH = N-,-
CH = CH-N = CH - , - (CH 2) 2 -O- (CH
_{2) 2 -, - (CH} 2) 3 -O- (CH 2) 3 - , and the like. Further, only ^one of R ¹ and R ² may be hydrogen.

[0023] X in the above formula ^- is ^{Cl -, Br -, 1/} 2
SO ₄ ²⁻ , 1 / 3PO ₄ ³⁻ inorganic acid residue, CH ₃ SO _{4
^{-, C 2 H 5 SO 4}} -, C m H 2m + 1 COO - (m is 1
(An integer of 6) organic sulfonic acid residue or carboxylic acid residue. The polymer of the above formula (A) that can be used in the present invention can be obtained, for example, by subjecting a compound of the following formula (C) to cyclopolymerization in the presence of a radical polymerization catalyst.

Embedded image The polymer of the above formula (B) can be obtained by subjecting the compound of the above formula (C) to cyclopolymerization in a system using sulfur dioxide as a solvent.

The polymer having a pyrrolidium ring in the main chain, which can be used in the present invention, may have a compound of the formula (C) and a compound having a polymerizable carbon-carbon unsaturated bond as a copolymerization component. Further, the molecular weight of the polymer is 5
The range is preferably from 100 to 1,000,000, preferably from 1,000 to 500,000. When the range is less than 500, although there is an antistatic effect, problems such as weak coating strength and easy blocking may occur.On the other hand, when it is higher than 1,000,000, the viscosity of the coating solution is high. Coatability may decrease.

When a coating layer is provided in the present invention, it is preferable that the coating layer contains a binder polymer in addition to the antistatic agent, from the viewpoint of durability of the coating layer. Examples of the binder polymer include polyvinyl alcohol, polyacrylamide, polyalkylene glycol, polyalkyleneimine, methylcellulose, hydroxycellulose, starches, polyurethane, polyester, polyacrylate, and chlorine-based polymers (polyvinyl chloride, vinyl chloride-vinyl acetate copolymer). Etc.), polyolefins and the like. When the coating layer is provided by a coating stretching method, among these, nonionic, cationic, and amphoteric organic polymers that can be used as an aqueous solution or aqueous dispersion are preferable,
Also, among them, especially when using polyurethane, polyester, polyacrylate, printing ink,
Good adhesion to UV-curable paints, PPC toners, etc.

These polymers can be made hydrophilic by imparting hydrophilicity by copolymerizing nonionic, cationic, or amphoteric hydrophilic components as one component of the monomers, and can be dispersed in water. In the present invention, the coating layer preferably contains an antistatic agent and a binder polymer, but the content of the antistatic agent is preferably in the range of 10 to 80% by weight. When the content of the antistatic agent is less than 10% by weight, the antistatic property may be insufficient, while
When the amount is more than 10% by weight, the durability of the coating film may be insufficient, and when a printing layer or the like is provided on the coating layer, the adhesiveness may be insufficient.

When a coating layer is provided in the present invention, a cross-linking agent may be used in combination as a component constituting the coating layer, and specific examples thereof include methylolated or alkylolated urea-based, melamine-based, guanamine-based, and acrylamide. System, polyamide compound, epoxy compound, aziridine compound, block polyisocyanate, silane coupling agent, titanium coupling agent, zircoaluminate coupling agent, and the like. These crosslinking components may be pre-bonded to the binder polymer. Further, inorganic particles may be contained for the purpose of improving the fixability and slipperiness of the coating layer, and specific examples include silica, alumina, kaolin, calcium carbonate, titanium oxide, and barium salt. Further, 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 contained.

In the present invention, the thickness of the coating layer is from 0.01 to
5 μm, more preferably 0.02 to 1 μm.
When the thickness of the coating layer is less than 0.01 μm, the uniformity of the coating thickness may be insufficient. On the other hand, when the coating thickness exceeds 5 μm, a problem may occur due to a decrease in slipperiness. In the present invention, a conventionally known coating method such as a bar coating method, a gravure coating method, or the like can be used in the same manner as the method of coating a polyester film with a coating layer, as in the case of forming a release layer described later. The release layer constituting the release film of the present invention is not particularly limited as long as it contains a material having a release property. Especially, it is preferable to contain a curable silicone resin. 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 and KS manufactured by Shin-Etsu Chemical Co., Ltd.
-775, KS-778, KS-779H, KS-85
6, X-62-2422, X-62-2461, Dow
Corning Asia Co., Ltd. DKQ3-202, DKQ
3-203, DKQ3-204, DKQ3-205, D
KQ3-210, YSR-30 manufactured by Toshiba Silicone Co., Ltd.
22, TPR-6700, TPR-6720, TPR-
6721, SD722 manufactured by Dow Corning Toray Co., Ltd.
0, SD7226, SD7229 and the like. Further, a release control agent may be used in combination to adjust the release property of the release layer.

In the present invention, as a method of further applying a release layer to the polyester film, a conventionally known coating method such as bar coating, reverse roll coating, gravure coating, air doctor coating, doctor blade coating, or the like may be used. it can. The thickness of the release layer is
0.01 to 5 μm is preferred. Release layer thickness of 0.01
When the thickness is less than μm, stability may be lower than that of coatability, and it may be difficult to obtain a uniform coating film. On the other hand, 5 μm
If the thickness is too large, the adhesion of the release layer itself, the curability and the like may be reduced. An intermediate layer such as an antistatic layer and an adhesive layer may be provided between the polyester film and the release layer, and the polyester film may be subjected to a surface treatment such as a corona treatment or a plasma treatment.

[0031]

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 of the present invention. In the examples and comparative examples, “parts” means “parts by weight”. The measuring method used in the present invention is as follows. (1) Intrinsic viscosity of polyester A mixed solvent of phenol / tetrachloroethane = 50/50 (weight ratio) is added to 1 g of polyester from which other polymer components and pigments incompatible with polyester are removed.
0 ml was added and dissolved, and the measurement was performed at 30 ° C. (2) Average particle size (d50: μm) The value of 50% of the integrated (weight basis) in the equivalent spherical distribution measured using a centrifugal sedimentation type particle size distribution analyzer (SA-CP3 manufactured by Shimadzu Corporation). The average particle size was used.

(3) Melt flow index (MF)
I): (g / 10 minutes) Measured according to JIS-K-6758-1981. The higher this value, the lower the melt viscosity of the polymer. (4) Evaluation 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 was measured. The peeling force was measured using a tensile tester ("Intesco Model 2001" manufactured by Intesco Corporation) under the condition of a tensile speed of 300 mm / min. (5) Evaluation of apparent density (D) of release film A square sample having a size of 10 cm x 10 cm was cut out from an arbitrary portion of the release film, the weight was measured, and the thickness at any 9 points was measured with a micrometer. The weight per unit volume was calculated from the average value and the weight. The number of measurements was n = 5, and the average was taken as the density of the release film.

(6) Evaluation of antistatic property (R) of release film: 50 m of internal electrode manufactured by Yokogawa Hewlett-Packard Company
1600 which is a concentric electrode having a diameter of 70 mm and an external electrode having a diameter of 70 mm
8A (trade name) was set at 23 ° C. under a 50% RH atmosphere, a voltage of 100 V was applied, and the surface resistivity was measured with the company's high resistance meter 4329A (trade name). Was determined. "Criterion" ○ ···· 10 ⁹ Ω or less △ exceed · · · · 10 ⁹ Omega more than 10 ¹³ Omega less × ···· 10 ¹³ Ω △ or is level with no practical problem.

(7) Evaluation of adhesion between antistatic layer and printing ink A UV curable ink having the following composition was applied on the antistatic layer to a thickness of 10 μm using a 300-mesh silk screen. Thereafter, the light was passed through a UV irradiation device “UVC-402 / 1HN: 302 / 1MH” manufactured by Ushio Inc., and the mercury lamp output was 160 w / cm, and the line speed was 5 m / cm.
The ink was cured at an interval of 100 mm between the lamp and the film, and immediately after the curing, the adhesiveness was evaluated by a cellophane tape peel test according to the following criteria. << UV curable ink composition >> UV curable ink (FDSS21 391 indigo, manufactured by Toyo Ink) 100 parts Reducer P 10 parts

<< Cellotape Peeling Test >> Cellotape (18 mm width) manufactured by Nichiban Co., Ltd. was applied to the ink surface to a length of 7 cm to prevent air bubbles from entering, and a constant load was applied with a manual load roll of 3 kg to apply the film. Fix, connect one end of cellophane tape to 500g weight, weight is 45cm
Was evaluated by a method in which a 180-degree peel test was started after the natural fall. << Judgment Criteria >> Evaluation 5: No ink is peeled off from the cellophane tape surface at all. Evaluation 4: Only less than 10% of ink is peeled off from the cellophane tape surface. Evaluation 3: ... 10-50% of the ink is cellophane. Evaluation 2 ... 50% or more of the ink peels off the cellophane tape surface Evaluation 1 ... Ink completely peels off the cellophane tape surface Evaluation 4 or higher is a level that is practically acceptable .

(8) Evaluation of Opacity (OD) of Release Film The transmission density by visual light was measured using a Macbeth densitometer TD-904. The average value of the measured values at five points was defined as the hiding degree value. The larger the value, the lower the light transmittance.

<Production of Polyester> Production Example 1 (Polyester 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, ethylene glycol slurry, 0.04 part of ethyl acid phosphate, germanium oxide 0.0
100 minutes after adding 1 part, the temperature was 280 ° C. and the pressure was 1
After the pressure reached 5 mmHg, the pressure was gradually reduced after that, and finally the pressure was 0.3 mmHg. Four hours later, the inside of the system was returned to normal pressure,
Polyester A1 was obtained. The intrinsic viscosity of the polyester A1 was 0.66.

Production Example 2 (Polyester A2) Polyester A1 obtained in Production Example 1 and MFI were 10 g / 1.
0 minute crystalline polypropylene chips were mixed in a ratio of 7: 1, and titanium oxide having an average particle size of 0.35 μm was further mixed with 2.5 minutes.
% By weight, 0.050% by weight of a fluorescent whitening agent and 0.3% by weight of a silicone-based surfactant were added to obtain a polyester A2. Production Example 3 (Polyester A3) Polyester A3 was obtained in the same manner as in Production Example 2, except that the mixing ratio of the polyester A1 and the crystalline polypropylene chips was changed to 2: 6.

Production Example 4 (Polyester A4) Polyester A4 was obtained in the same manner as in Production Example 2, except that a crystalline polypropylene chip and a silicone-based surfactant were not added. Production Example 5 (Polyester A5) In Production Example 2, the amount of titanium oxide was 0.05% by weight.
Polyester A5 was obtained in the same manner as in Production Example 2 except that Production Example 6 (Polyester A6) A polyester A6 was obtained in the same manner as in Production Example 2, except that the mixing ratio of the polyester A1 and the crystalline polypropylene chips was changed to 5: 3.

Example 1 Polyester A2 produced in Production Example 2 was dried at 180 ° C. for 4 hours in an inert gas atmosphere, and dried by a melt extruder.
It was melted at 0 ° C., 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 3.3 times in the longitudinal direction at 85 ° C. Next, after applying a coating material having the following composition, the film was guided to a tenter and stretched 3.3 times in the transverse direction at 100 ° C., and then heat-fixed at 230 ° C., and the thickness of the dried coating layer was 0.1 mm. 15μm thickness 75μ
Thus, a polyester film provided with a coating layer of m was obtained.
Further, a release layer having the following composition was coated on the surface opposite to the surface on which the coating layer was applied, and the coating thickness after drying was 0.1%.
(G / m ² ) to obtain a release film.

<< Coating Agent Composition >> 70% by weight of polymer A containing ionized nitrogen element in the main chain Binder (Polyacrylate cationic water dispersion: Nicazole FX-625, Nippon Carbide Co., Ltd.) 30% by weight

[0042]

Embedded image

<< Releasing Agent Composition >> Curable Silicone Resin (KS-847H: Shin-Etsu Chemical) 100 parts Curing Agent (PL-50T: Shin-Etsu Chemical) 1 part MEK / toluene mixed solvent 1500 parts

Example 2 A release film was obtained in the same manner as in Example 1 except that the mixing ratio of the coating agent in Example 1 was changed to the following ratio. << Coating composition >> 20% by weight of polymer A containing ionized nitrogen element in the main chain Binder (Polyacrylate cationic water dispersion: Nippon Carbide Co., Ltd., Nicazole FX-625) 80% by weight

Example 3 A release film was obtained in the same manner as in Example 1 except that the coating composition in Example 1 was changed to the following coating composition. << Coating Composition >> 70% by weight of polymer B containing ionized nitrogen element in the main chain Binder (nonionic aqueous dispersion of ternary copolymer of methyl methacrylate / ethyl acrylate / methylol acrylamide: monomer ratio: 47.5) /47.5/5 mol%) 30% by weight

[0046]

Embedded image

Example 4 A release film was obtained in the same manner as in Example 1 except that the coating composition in Example 1 was changed to the following coating composition. << Coating agent composition >> Polymer C containing ionized nitrogen element in main chain 40% by weight Binder (polyvinyl alcohol: Gohsenol G L-05, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) 30% by weight Crosslinking agent (methoxymethylmelamine) 30% by weight %

[0048]

Embedded image

Example 5 A release film was obtained in the same manner as in Example 1 except that the coating composition in Example 1 was changed to the following coating composition. << Coating Composition >> 70% by weight of polymer D containing ionized nitrogen element in the main chain Binder (nonionic aqueous dispersion of terpolymer of methyl methacrylate / ethyl acrylate / methylolacrylamide: monomer ratio: 47.5) / 4 7.5 / 5 mol%) 30% by weight

[0050]

Embedded image

Example 6 A release film was obtained in the same manner as in Example 1 except that the coating composition in Example 1 was changed to the following coating composition. << Coating agent composition >> Polymer containing a pyrrolidium ring in the main chain (manufactured by Daiichi Kogyo Seiyaku Co., Ltd .: Sharol DC-902P) 20% by weight Binder (acrylic resin) 60% by weight Crosslinking agent (methoxymelamine) 20% by weight

Example 7 A release film was obtained in the same manner as in Example 1 except that the coating composition in Example 1 was changed to the following coating composition. << Composition of Coating Agent >> 20% by weight of a polymer containing a pyrrolidium ring in the main chain (PAS-88 manufactured by Nitto Boseki) 60% by weight of a binder (acrylic resin) 20% by weight of a crosslinking agent (methoxymelamine)

Example 8 A release film was obtained in the same manner as in Example 1 except that the composition of the release agent in Example 1 was changed to the following release agent composition. << Releasing agent composition >> Curable silicone resin (KS-723A: Shin-Etsu Chemical Co., Ltd.) 100 parts (KS-723B: Shin-Etsu Chemical Co., Ltd.) 5 parts Curing agent (PS-3: Shin-Etsu Chemical Co., Ltd.) 3 parts MEK / toluene mixed solvent 1500 copies

Example 9 A release film was obtained in the same manner as in Example 1 except that the composition of the release agent in Example 1 was changed to the following composition of the release agent. << Releasing Agent Composition >> 100 parts of curable silicone resin (KS-881: manufactured by Shin-Etsu Chemical) 2.5 parts of curing agent (PS-80: manufactured by Shin-Etsu Chemical) 1500 parts of MEK / toluene mixed solvent 1500 parts Example 10 In Example 1 Polyester A2 to Polyester A6
A release film was obtained in the same manner as in Example 1 except for changing to.

Comparative Example 1 A release film was obtained in the same manner as in Example 1 except that the release layer was not provided. Comparative Example 2 Polyester A2 in Example 1 was replaced with Polyester A4
A release film was obtained in the same manner as in Example 1 except for changing to. Comparative Example 3 Polyester A2 in Example 1 was replaced with Polyester A3
An attempt was made to form a film in the same manner as in Example 1 except that the film was changed to, but the film was broken and no film was obtained.

Comparative Example 4 A release film was obtained in the same manner as in Example 1 except that the amount of each polymer constituting the coating agent was changed to the following amount. << Coating agent composition >> Polymer A containing ionized nitrogen element in the main chain 5% by weight Binder (Polyacrylate cationic water dispersion: Nippon Carbide Co., Ltd., Nicazole FX-625) 75% by weight Crosslinking agent Methoxymethylmelamine 20% by weight % Comparative Example 5 A release film was obtained in the same manner as in Example 1, except that polyester A5 was used instead of polyester A2.

Comparative Example 6 A release film was obtained in the same manner as in Example 1 except that the coating composition was changed to the following coating composition. << Coating Agent Composition >> Polyacrylate antistatic agent containing quaternary ammonium salt in side chain (manufactured by Mitsubishi Chemical Corporation, ST-1000) 40% by weight Crosslinking agent (methoxymethylmelamine) 60% by weight Comparative Example 7 Coating layer in Example 1 Was not obtained and a release film was obtained in the same manner.

Comparative Example 8 A release film was obtained in the same manner as in Example 1 except that the coating composition was changed to the following coating composition. << Coating agent composition >> 5% by weight of a polymer containing a pyrrolidium ring in the main chain (manufactured by Daiichi Kogyo Seiyaku Co., Ltd .: Sharole DC-902P) 75% by weight of a binder (acrylic resin) 20% by weight of a crosslinking agent (methoxymelamine) The properties of the release films obtained are summarized in Table 1 below.

[0059]

[Table 1]

[0060]

The release film of the present invention has excellent release properties, cushioning properties and antistatic properties and is extremely useful when used for various types of release.

Claims (10)

[Claims] 1. A release film having a release layer on at least one surface of a polyester film containing fine bubbles, wherein the release film satisfies the following formulas (1) to (4) simultaneously. 0.40 ≦ D ≦ 1.30 (1) 5 ≦ F ≦ 1500 (2) R ≦ 10 ¹³ (3) 0.3 ≦ OD (4) (In the above formula, D is Apparent density of release film (g / c
m ³ ), F is the peeling force of the release film (gf / 50 mm)
Width), R is the surface specific resistance (Ω) of any one surface of the release film, and OD represents the degree of concealment of the release film. 2. The release film according to claim 1, further comprising a coating layer containing an antistatic agent and a binder polymer on at least one surface. 3. The release film according to claim 2, wherein the antistatic agent is a polymer containing, in its main chain, either an ionized nitrogen element or a pyrrolidium ring. 4. The method according to claim 1, further comprising a thermoplastic resin substantially incompatible with the polyester.
The release film according to any one of the above. 5. The release film according to claim 4, wherein the thermoplastic resin substantially incompatible with the polyester comprises a polypropylene resin. 6. The release film according to claim 2, wherein a coating layer containing an antistatic agent and a binder polymer is applied by a coating and stretching method. 7. The antistatic agent content in the coating layer is 10 to 10.
The release film according to claim 6, which is 80% by weight. 8. The release film according to claim 1, wherein the release layer contains a curable silicone resin. 9. The release film according to claim 1, wherein the polyester film contains white particles. 10. The white particles are titanium oxide particles and / or barium sulfate particles.
The release film according to 1.