JPH10278204A - Mold release film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold release film excellent in releasability, cushioning properties and antistatic properties. SOLUTION: This film is constituted by providing a release layer to at least the single surface of a laminated polyester film obtained by laminating a polyester B layer not substantially containing fine air bubbles on at least the single surface of a polyester A layer containing fine air bubbles and simultaneously satisfies 0.40<=D<=1.30, 5<=F<=1500, R<=10<13> , 0.3<=OD and 1<=TA/TB<=500 [wherein D is apparent density (g/cm<3> ) of the mold release film, F is the peeling strength (gf/50 mm width) of the mold release film, R is the surface intrinsic resistance (Ω) of either one of surfaces of the mold release film, OD is the concealing degree of the mold release film, TA/TB is a ratio of the thickness TA (μm) of the polyester A layer and the total thickness (μm) of the polyester B layer].

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 film having a release layer on at least one side of a laminated polyester film obtained by laminating a polyester B layer containing substantially no microbubbles on at least one side of a polyester A layer containing microbubbles, wherein the following formula (1) ~
(5) A release film characterized by simultaneously satisfying (5).

[0005]

0.40 ≦ D ≦ 1.30 (1) 5 ≦ F ≦ 1500 (2) R ≦ 10 ¹³ (3) 0.3 ≦ OD (4) 1 ≦ TA / TB ≦ 500 ... (5) (where D is the apparent density of the release film (g / c)
m ³ ), F is the peeling force of the release film (gf / 50 mm)
Width), R is the surface resistivity (Ω) of any one side of the release film, OD is the degree of concealment of the release film, and TA / TB is the thickness TA (μm) of the polyester A layer and the polyester B
(Represents the ratio to the total thickness TB (μm) of the layer)

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. In the laminated polyester film constituting the release film of the present invention, a polyester B layer containing substantially no fine bubbles is laminated on at least one surface of a polyester A layer containing fine bubbles. The laminated polyester film is characterized in that it has a layer configuration of B / A or B / A / B. Further, it is preferable that all the polyester layers are laminated by a so-called co-extrusion method in which they are melt-extruded together from an extrusion die.

The polyester to be used is a polyester obtained by polycondensing an aromatic dicarboxylic acid and an aliphatic glycol. Examples of the aromatic dicarboxylic acid include terephthalic acid and 2,6-naphthalenedicarboxylic acid. Examples of the aliphatic glycol include ethylene glycol, diethylene glycol, and 1,4-cyclohexanedimethanol. Representative polyesters include polyethylene terephthalate (PET),
Examples thereof include polyethylene-2,6-naphthalenedicarboxylate (PEN). The polyester may be a copolymer containing a third component. When the copolymerized polyester is used, the dicarboxylic acid component includes isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid and oxycarboxylic acid (for example, P-oxybenzoic acid). And the glycol component includes one or more of ethylene glycol, diethylene glycol, propylene glycol, butanediol, 1,4-cyclohexanedimethanol, neopentyl glycol, and the like.

The fine bubbles contained in the laminated polyester film of the present invention are formed by various means, but are preferably formed of a thermoplastic resin substantially incompatible with polyester. Cushioning properties can be obtained in the laminated polyester film by the fine bubbles. 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.

As the above polypropylene, a crystalline polypropylene homopolymer having usually 95 mol% or more, preferably 98 mol% or more of propylene units is preferable.
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 melt flow index (MFI) of the polypropylene is 0.5 to 30 g / min, preferably 1.0 to 15 g / min.
A range of minutes is preferred. When the MFI is less than 0.5 g / min, the generated bubbles may be too large. On the other hand, when the MFI exceeds 30 g / min, it may be difficult to control the density.

In the present invention, the content of the thermoplastic resin substantially incompatible with the polyester contained in the polyester A layer is usually 5 to 45% by weight, preferably 10 to 45% by weight.
The range is 35% by weight, more preferably 15 to 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 blended in the polyester A layer, the surface activity is controlled for the purpose of controlling the size of bubbles formed in the polyester film and the like. It is preferable to use an agent 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 A layer is not particularly limited.
The range is preferably 001 to 1.0% by weight, more preferably 0.01 to 0.5% by weight. When the content of the surfactant is less than 0.001% by weight, the foam-regulating effect may be insufficient.
If it exceeds 1.0% by weight, during the film manufacturing process,
In particular, problems may occur in the extrusion process.

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.

Further, using a kneading extruder with a vent,
Slurry of particles dispersed in glycol or water
Method of blending with polyester material or kneading
Using an extruder, dry the particles and the polyester raw material
It is performed by a blending method or the like. Further above
In addition to the particles, a fluorescent whitening agent is used
You may. Fluorescent whitening in polyester layer in the present invention
The agent content is preferably in the range of 0 to 0.30% by weight. Departure
The apparent density (D) of the light release film is 0.40 to 0.40.
1.30 g / cm ^ThreeRange. Look of release film
If the density of the mold is less than 0.40,
Insufficient mechanical strength, while exceeding 1.30
In this case, the cushioning property of the release film is impaired.

The release force (F) of the release film of the present invention is:
It is in the range of 5 to 1500 gf / 50 mm width. When the peeling force of the release film is less than 5 gf / 50 mm width, the peeling force is too light to cause problems such as peeling during handling. On the other hand, when the peeling force exceeds 1500 gf / 50 mm width, the peeling force is too large. In addition, problems such as difficulty in peeling off occur. The surface specific resistance (R) of any one surface 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.

Incidentally, in addition to the above-mentioned particles and fluorescent whitening agent, 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 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. The ratio (TA / TB) of the thickness of each polyester layer of the laminated polyester film constituting the release film in the present invention is from 1 to 1.
Must be in the range of 500. When TA / TB is less than 1, the flexibility of the release film is insufficient. On the other hand, when it exceeds 500, the polyester A layer containing microbubbles contaminates the production equipment during production. Failure occurs.

Incidentally, in addition to the above-mentioned particles and fluorescent brightener, conventionally known antioxidants, heat stabilizers, lubricants, dyes, pigments and the like may be added to the laminated polyester film of the present invention, if necessary. Can be. Next, a production example of the laminated polyester film in the present invention will be specifically described, but is not limited to the following production example.
That is, using the polyester raw material described above, using a plurality of extruders, a multi-layer multi-manifold die or a feed block, laminating each polyester and extruding a multi-layer molten sheet from a die, a cooling roll It is preferable to obtain a non-stretched sheet by cooling and solidifying the sheet. In this case, it is preferable to increase the adhesion between the sheet and the rotary cooling drum in order to improve the flatness of the sheet,
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 11 ° C.
0 ° 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 70 to 13
0 ° C., preferably 80 to 120 ° C .;
It is usually 3.0 to 7 times, preferably 3.5 to 6 times. After stretching, heat treatment is performed at a temperature of 170 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, 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-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).

[0023]

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.

[0025] 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 formula (C) and a compound having a polymerizable carbon-carbon unsaturated bond as a copolymerization component. Further, the molecular weight of the polymer is 500 to 1,000,000, preferably 1000 to 50
The range of ten thousand is good. When the range is less than 500, although there is an antistatic effect, problems such as weak coating strength and easy blocking may occur.
If it is higher than 10,000, the viscosity of the coating solution may be so high that the coating properties may be reduced.

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 a nonionic, cationic or amphoteric hydrophilic component as one component of the monomer, 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 crosslinking 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 a bar coat, a reverse roll coat, a gravure coat, an air doctor coat, and a doctor blade coat can be used. The thickness of the release layer is preferably 0.01 to 5 μm from the viewpoint of coatability. When the thickness of the release layer is less than 0.01 μm, stability may be lacked from the viewpoint of coatability, and it may be difficult to obtain a uniform coating film. On the other hand, if the thickness exceeds 5 μm,
In some cases, the adhesion of the coating film, the curability, and the like of the release layer itself may decrease. An intermediate layer such as an antistatic layer and an adhesive layer may be provided between the polyester film and the release layer. The polyester film may be subjected to a surface treatment such as a corona treatment and a plasma treatment.

[0033]

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 (d ₅₀ : μm) 50% integrated (weight basis) in equivalent spherical distribution measured using a centrifugal sedimentation type particle size distribution analyzer (SA-CP3 manufactured by Shimadzu Corporation) As the average particle size.

(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. After that, 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 / m.
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 so as to prevent air bubbles from entering, and a constant load was applied with a 3 kg manual load roll. 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. (9) Measurement of the thickness of each polyester layer of the release film A small piece of the sample sample cut in the lateral direction is embedded in a resin in which a curing agent and an accelerator are mixed with an epoxy resin, and cut with an ultramicrotome. Observed dissolved samples were used. The cross section was taken with a transmission electron microscope H-90 manufactured by Hitachi, Ltd.
Photographs were taken using a No. 00, and the thickness of each layer was measured. However,
The imaging conditions were set at an acceleration voltage of 300 kV, and the magnification was set in the range of 1,000 to 100,000 times according to the outermost layer thickness. The thickness was measured at 50 points, and 10 points were measured from the thicker one and 1 from the thinner.
Zero points were deleted and the total value of 30 points was averaged to obtain a measured value.

(10) Evaluation of the degree of contamination of the production apparatus (cast roll) The degree of contamination of the cast roll during the formation of the laminated polyester film was evaluated according to the following criteria. << Judgment Criteria >> ・: almost no contamination of the cast roll ×: × contamination of the cast roll is confirmed ○ is a practically acceptable level.

<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. After 4 hours, the inside of the system was returned to normal pressure to obtain polyester A1. 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) In Production Example 2, the addition amount of titanium oxide was 0.05% by weight.
Polyester A4 was obtained in the same manner as in Production Example 2 except that

Production Example 5 (Polyester A5) Polyester A5 was obtained in the same manner as in Production Example 2 except that the mixing ratio of polyester A1 and crystalline polypropylene chips was changed to 5: 3. Production Example 6 (Polyester B) Polyester B 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 of Laminated Polyester Film> Production Example 7 (Laminated Polyester Film F1) Polyesters A2 and B were each dried at 180 ° C. for 4 hours in an inert gas atmosphere, and dried by a separate melt extruder.
The polymer was melt-extruded at 0 ° C., these polymers were joined together in a feed block, laminated, and cooled and solidified on a cooling roll having a surface temperature set to 40 ° C. using an electrostatic 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 agent having the following composition to the polyester A2 layer side, the film was guided to a tenter and stretched 3.3 times in the transverse direction at 100 ° C.
And heat-fixed, and the thickness (DRY) of the coating layer is 0.15.
A 125 μm-thick laminated polyester film F1 provided with a μm coating layer was obtained. The layer configuration is B / A2 / B = 5 /
115/5 (μm).

<< 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

Embedded image

Production Example 8 (Laminated polyester film F
2) In Production Example 7, polyester A2 was replaced with polyester A5
Except that the layer structure was changed to B / A5 / B = 5.
/ 115/5 (μm) laminated polyester film F2
I got Production Example 9 (Laminated Polyester Film F3) A laminated polyester film F3 having a thickness of 125 (μm) was obtained in the same manner as in Production Example 7, except that polyester B was changed to polyester A2. Production Example 10 (Laminated Polyester Film F4) In Production Example 7, the layer configuration was B / A2 / B = 60/5/6.
A laminated polyester film F4 was obtained in the same manner as in Production Example 7 except that the thickness was changed to 0 (μm).

Production Example 11 (Laminated polyester film F
5) In Production Example 7, polyester A2 was replaced with polyester A3
And a layer structure was obtained in the same manner as in Production Example 7 except that the layer structure was changed to B / A3 / B = 1/123/1 (μm). Production Example 12 (Laminated Polyester Film F6) In Production Example 7, polyester A2 was replaced with polyester A4
In the same manner as in Production Example 7 except that the layer configuration was changed to obtain a laminated polyester film F6 having a layer configuration of B / A4 / B = 1/123/1 (μm).

Production Example 13 (Laminated polyester film F
7) A laminated polyester film F7 having a thickness of 125 (μm) was obtained in the same manner as in Production Example 7, except that the polyester A2 was changed to the polyester B. Production Example 14 (Laminated Polyester Film F8) In Production Example 7, the layer configuration was changed to B / A2 / B = 1/123 /
A laminated polyester film F8 was obtained in the same manner as in Production Example 7, except that the thickness was changed to 1 (μm). Production Example 15 (Laminated Polyester Film F9) A laminated polyester film F9 was obtained in the same manner as in Production Example 7, except that the mixing ratio of the coating agent was changed to the following ratio.

<< Composition of Coating Agent >> 20% 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.) 80% by weight Production Example 16 ( Laminated Polyester Film F10) A laminated polyester film F10 was obtained in the same manner as in Production Example 7, except that the composition of the coating agent was changed to the following coating composition.

<< Composition of Coating Agent >> 70% by weight of polymer B containing ionized nitrogen element in the main chain Binder (nonionic aqueous dispersion of terpolymer of methyl methacrylate / ethyl acrylate / methylol acrylamide: monomer ratio: 47.5 / 47.5 / 5 mol%) 30% by weight

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Production Example 17 (Laminated polyester film F
11) In Production Example 7, a laminated polyester film F11 was obtained in the same manner as in Production Example 7, except that the composition of the coating agent was changed to the following coating agent 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 %

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Production Example 18 (Laminated polyester film F
12) In Production Example 7, a laminated polyester film F12 was obtained in the same manner as in Production Example 7, except that the composition of the coating agent was changed to the following coating agent 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

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Production Example 19 (Laminated polyester film F
13) In Production Example 7, a laminated polyester film F13 was obtained in the same manner as in Production Example 7, except that the composition of the coating agent was changed to the following coating agent 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

Production Example 20 (Laminated polyester film F
14) In Production Example 7, a laminated polyester film F14 was obtained in the same manner as in Production Example 7, except that the composition of the coating agent was changed to the following coating agent composition. << Composition of Coating Agent >> 20% by weight of a polymer containing a pyrrolidium ring in the main chain (PAS-88 manufactured by Nitto Bo) 60% by weight of a binder (acrylic resin) 20% by weight of a crosslinking agent (methoxymelamine)

Production Example 21 (Laminated polyester film F
15) A laminated polyester film F15 was obtained in the same manner as in Production Example 7, except that the mixing ratio of the coating agent was changed to the following ratio. << 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) 90% by weight Crosslinking agent Methoxymethylmelamine 5% by weight %

Production Example 22 (Laminated polyester film F
16) In Production Example 7, a laminated polyester film F16 was obtained in the same manner as in Production Example 7, except that the composition of the coating agent was changed to the following coating agent composition. << Coating composition >> Polyacrylate-based antistatic agent containing quaternary ammonium salt in side chain (ST-1000, manufactured by Mitsubishi Chemical Corporation) 40% by weight Crosslinking agent (methoxymethylmelamine) 60% by weight

Production Example 23 (Laminated polyester film F
17) In Production Example 7, a laminated polyester film F17 was obtained in the same manner as in Production Example 7, except that the composition of the coating agent was changed to the following coating agent composition. << Coating composition >> Polymer containing a pyrrolidium ring in the main chain (manufactured by Daiichi Kogyo Seiyaku Co., Ltd .: Sharol DC-902P) 5% by weight Binder (acrylic resin) 75% by weight Crosslinking agent (methoxymelamine) 20% by weight

Example 1 A coating thickness after drying was 0.1 (g) on the surface of the laminated polyester film F1 obtained in Production Example 7 opposite to the surface on which the release layer having the following composition was coated. / M ² ) to obtain a release film. << Composition of release agent >> 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 In Example 1, the laminated polyester film F1 was replaced with F9
A release film was obtained in the same manner as in Example 1 except for changing to. Example 3 In Example 1, the laminated polyester film F1 was replaced with F1.
A release film was obtained in the same manner as in Example 1 except that the value was changed to 0. Example 4 In Example 1, the laminated polyester film F1 was replaced with F1.
Except for changing to 1, a release film was obtained in the same manner as in Example 1.

Example 5 In Example 1, the laminated polyester film F1 was replaced with F1.
Except for changing to 2, a release film was obtained in the same manner as in Example 1. Example 6 In Example 1, the laminated polyester film F1 was replaced with F1.
Except for changing to 3, a release film was obtained in the same manner as in Example 1. Example 7 In Example 1, the laminated polyester film F1 was replaced with F1.
Except having changed to 4, it carried out similarly to Example 1, and obtained the release film.

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 composition of the release agent. << Releasing agent composition >> Curable silicone resin (KS-723A: Shin-Etsu Chemical) 100 parts (KS-723B: Shin-Etsu Chemical) 5 parts Curing agent (PS-3: Shin-Etsu Chemical) 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. << Release Agent Composition >> Curable Silicone Resin (KS-881: Shin-Etsu Chemical) 100 parts Curing Agent (PS-80: Shin-Etsu Chemical) 2.5 parts MEK / toluene mixed solvent 1500 parts Example 10 In Example 1, Laminated polyester film F1 to F2
A release film was obtained in the same manner as in Example 1 except for changing to.

Example 11 In Example 1, the laminated polyester film F1 was replaced with F8
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 applied. Comparative Example 2 In Example 1, the laminated polyester film F1 was replaced with F7.
A release film was obtained in the same manner as in Example 1 except for changing to.

Comparative Example 3 In Example 1, the laminated polyester film F1 was replaced with F5
A release film was obtained in the same manner as in Example 1 except for changing to. Comparative Example 4 In Example 1, the laminated polyester film F1 was replaced with F1.
Except having changed to 5, it carried out similarly to Example 1, and obtained the release film. Comparative Example 5 The laminated polyester film F1 of Example 1 was replaced with F6.
A release film was obtained in the same manner as in Example 1 except for changing to.

Comparative Example 6 In Example 1, the laminated polyester film F1 was replaced with F1.
Except for changing to 6, a release film was obtained in the same manner as in Example 1. Comparative Example 7 A release film was obtained in the same manner as in Example 1 except that the coating layer was not provided. Comparative Example 8 In Example 1, the laminated polyester film F1 was replaced with F1.
Except for changing to 7, a release film was obtained in the same manner as in Example 1.

Comparative Example 9 In Example 1, the laminated polyester film F1 was replaced with F3
A release film was obtained in the same manner except for changing to. Comparative Example 10 In Example 1, the laminated polyester film F1 was replaced with F4
A release film was obtained in the same manner except for changing to. The results obtained above are summarized in Tables 1 and 2 below.

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[Table 1]

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[Table 2]

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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 film having a release layer on at least one side of a laminated polyester film obtained by laminating a polyester B layer containing substantially no fine bubbles on at least one side of a polyester A layer containing fine bubbles,
A release film characterized by simultaneously satisfying the following formulas (1) to (5). 0.40 ≦ D ≦ 1.30 (1) 5 ≦ F ≦ 1500 (2) R ≦ 10 ¹³ (3) 0.3 ≦ OD (4) 1 ≦ TA / TB ≦ 500 ... (5) (where D is the apparent density of the release film (g / c)
m ³ ), F is the peeling force of the release film (gf / 50 mm)
Width), R is the surface resistivity (Ω) of any one side of the release film, OD is the degree of concealment of the release film, and TA / TB is the thickness TA (μm) of the polyester A layer and the polyester B
(Represents the ratio to the total thickness TB (μm) of the layer) 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 method according to claim 2, wherein the coating layer is applied by a coating stretching method (in-line coating method).
6. The release film according to any one of items 1 to 5. 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. Polyester A layer or polyester B
9. The layer according to claim 1, wherein the layer contains white particles.
The release film according to any one of the above. 10. The white particles are titanium oxide particles and / or barium sulfate particles.
The release film according to 1.