JPH0824891B2 - Peeling sheet and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [A] Field of Industrial Application The present invention provides a layer having excellent blocking resistance and excellent internal peeling prevention property on a sheet-like substrate such as paper, laminated paper, synthetic paper and plastic film. And a method for manufacturing the same.

[B] Conventional Technology Silicone release sheets having a release layer made of an organic polysiloxane provided on a sheet-like substrate such as paper, laminated paper, synthetic paper, and plastic film have been used in many applications in recent years. As a method for forming the release layer, a solution of a condensation-type or addition-type silicone resin containing an organic tin compound or other heavy metal salt, and a platinum catalyst, or an emulsion is applied, and then 120 ° C to 180 ° C in a hot air oven. Generally, a method of heating to form a cured film is used.

However, when such a high-temperature heat treatment is applied to a release sheet using a paper substrate, the paper substrate needs to have heat resistance, and wrinkles and curls easily occur due to water evaporation inside the paper substrate. Further, it has a drawback that pinholes are easily generated in the peeling layer due to evaporation of water. It is a commonly used method to use a substrate laminated with polyethylene or vinylidene chloride on the paper surface for the purpose of overcoming such drawbacks and for reducing the absorption of a release layer-forming silicone resin into paper. When the silicone resin is cured, softening, melting, and shrinkage of the laminate layer occur, resulting in non-uniformity of the laminate substrate surface that hinders the peeling performance, and pinholes are generated due to bubble generation due to water evaporation in the paper. It had the drawback of being easy. Solvent-free silicone resins are one of the ways to overcome these drawbacks, especially ultraviolet rays (UV).
A low-temperature curing type release paper manufacturing technology has been developed in which radiation curing is performed using a silicone resin having a polymerizable functional group (hereinafter, UV and EB are collectively referred to as radiation) by electron beam (EB) irradiation. It was According to these methods, the occurrence of curls, wrinkles, pinholes, etc. due to high temperature treatment during the release paper manufacturing process is relatively prevented, but
In the production of release paper using a paper substrate, the problem that a high-viscosity resin must be used in order to prevent the silicone resin from seeping into the paper substrate and reduce variations in coating amount, and a film-based release sheet In the production, the silicone film formed by the low temperature curing type method of performing radiation curing has a problem that it has poor adhesion to the film substrate. As one example of means for solving such a problem, the present inventors have previously provided a radiation-polymerizable composition layer (hereinafter referred to as a primer layer) having good adhesiveness with a paper or film substrate on at least one surface thereof. Apply
Further, by coating a composition layer which is radiation-polymerizable and has releasability after curing (hereinafter referred to as a release layer) thereon, and by providing a layer in which both layers are simultaneously cured by irradiation with radiation, the above problems can be solved. Has applied for a release sheet that has solved the above problem. (Japanese Patent Application No. 62-239422) [C] Problems to be Solved by the Invention The above-mentioned method solves the above-mentioned problems, and since radiation curing is a kind of cold curing, the release layer and the primer layer are heated. Although not mixed by diffusion,
In the case of continuously producing such a release sheet, any coater such as a gravure coater, a bar coater, a roll coater, an air knife coater, a U comma coater, an AKKU coater and a smoothing coater which is used for coating a usual release layer can be used. Even after using the primer layer, it is very difficult to apply the release layer uniformly and thinly without mixing with the primer layer, resulting in variations in the release properties of the produced release sheet, The cost is high, and there is a problem that a love-off may occur in some cases. Especially when attempting high-speed processing, the mixing of the primer layer and the release layer was extremely vigorous,
In extreme cases, it was difficult to apply multiple layers to the extent that it did not function as a release sheet.

[D] Means for Solving the Problems The inventors of the present invention have conducted intensive research into means for solving the above-mentioned problems, and as a result have found the following method. That is, in a release sheet having a release layer on at least one side of a paper or film substrate, a primer layer made of a coating solution containing a radiation-polymerizable resin having good adhesiveness with the substrate as a main component is provided on the substrate, and On top of that, there is a layer of a stripping solution whose main component is a composition that is radiation-polymerizable and has releasability after curing applied by a free-fall vertical curtain, and both layers are cured by irradiation. It is an invention of a characteristic peeling sheet and a manufacturing method thereof. According to the present invention, multiple coating can be performed without mixing the primer layer and the release layer, and simultaneous curing can be performed without mixing both layers. Only in the method of the present invention, the release layer is prevented from bleeding into the substrate, the release layer and the primer layer are simultaneously cured, the adhesion between the release layer and the substrate is improved, the coating property of the release layer is improved, the overheating of the substrate is prevented, and pinholes are formed. It is possible to simultaneously control the generation of wrinkles and curls.

Hereinafter, the present invention will be described in detail. That is, the present invention provides a primer sheet having good adhesiveness to a substrate and a release layer having good adhesiveness and releasability on a substrate by a free-fall vertical curtain coating method, and a release sheet prepared by electronic irradiation, and a release sheet thereof. A manufacturing method is provided. The radiation-polymerizable composition (hereinafter, simply referred to as a radiation-polymerizable composition) that constitutes the primer layer having good adhesion to the substrate herein means a compound having an acryloyl group, a methacryloyl group, an epoxy group, vinylpyrrolidone, or the like. Is. The radiation-polymerizable composition used in the present invention includes an unsaturated polyester having a reactive group at the molecular end or at the molecular side chain,
It can be used alone or with other solvents such as modified unsaturated polyester, acrylic polymer and monomer having an unsaturated bond, but the affinity between the substrate and the radiation-polymerizable composition, and the radiation-polymerizable composition and radiation It is selected in consideration of the affinity with the polymerizable stripping solution. Hereinafter, typical compounds among the compounds constituting the radiation-polymerizable composition will be exemplified.

(A) Polyester acrylate, polyester methacrylate For example, Aronix M-5300, Aronix M-54
00, Aronix M-5500, Aronix M-5600, Aronix M-5700, Aronix M-6100, Aronix M-6200, Aronix M-6300, Aronix M
-6500, Aronix M-7100, Aronix M-803
0, Aronix M-8060, Aronix M-8100 (Trade name of Toagosei Chemical Industry Co., Ltd.), Viscort 70
0, Viscoat 3700 (Osaka Organic Chemical Industry Co., Ltd. product name), Kayarad HX-220, Kayarad HX-620 (Nippon Kayaku Co., Ltd. product name) (b) Epoxy acrylate, epoxy methacrylate For example, NK Ester, EA-800, NK ester, EPM-80
0 (above, trade name of Shin-Nakamura Chemical Co., Ltd.), Viscoat 600,
Viscort 540 (Osaka Organic Chemical Industry Co., Ltd. trade name), Photomer 3016, Photomer 3082 (San Nopco Ltd. trade name) (c) Urethane acrylate, urethane methacrylate For example, Aronix M-1100, Aronix M-12
00, Aronix M-1210, Aronix M-1250, Aronix M-1260, Aronix M-1300, Aronix M-1310 (above, trade name of Toagosei Chemical Industry Co., Ltd.), Viscoat 812, Viscoat 823, Viscoat 823.
(Above, trade name of Osaka Organic Chemical Industry Co., Ltd.), NK ester, U-108-A, NK ester, U-4HA (above, trade name of Shin Nakamura Chemical Co., Ltd.) (d) monofunctional acrylate, monofunctional Methacrylate For example, methyl acrylate, ethyl acrylate,
Butyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, tetrahydrofurfuryl acrylate, phenoxyethyl acrylate, cyclohexyl acrylate, cyclohexyl methacrylate, benzyl acrylate, glycidyl methacrylate, N, N -Dimethylaminoethyl acrylate, N, N-dimethylaminoethyl methacrylate, N, N-diethylaminoethyl methacrylate, butoxyethyl acrylate and the like. Ethylene oxide-modified phenoxyphosphoric acid acrylate Ethylene oxide-modified butoxylated phosphoric acid acrylate, or Aronix M- under the trade name of Toa Gosei Chemical Industry Co., Ltd.
101, Aronix M-102, Aronix M-111, Aronix M-113, Aronix M-114, Aronix M-117, Aronix M-152, Aronix M-15
4 and so on.

(E) Polyfunctional acrylate, polyfunctional methacrylate For example, 1,6-hexanediol diacrylate, 1,6
-Hexanediol dimethacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, polypropylene glycol diacrylate, polypropylene glycol dimethacrylate, pentaerythritol diacrylate, dipentaerythritol hexaacrylate, isocyanuric acid diester Acrylate, pentaerythritol triacrylate, isocyanuric acid triacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, ethylene oxide-modified pentaerythritol tetraacrylate, propylene oxide-modified pentaerythritol tetraacrylate, propylene oxide De-modified dipentaerythritol polyacrylate, such ethylene oxide-modified dipentaerythritol polyacrylate. The product name of Toagosei Kagaku Kogyo Co., Ltd. is Aronix M-21.
0, Aronix M-215, Aronix M-220, Aronix M-230, Aronix M-233, Aronix M-240, Aronix M-245, Aronix M-30
5, Aronix M-309, Aronix M-310, Aronix M-315, Aronix M-320, Aronix M-325, Aronix M-330, Aronix M-40
0, TO-458, TO-747, TO-755, THIC, TA2, etc.

In addition, the composition of the stripping solution having releasability after curing (hereinafter simply referred to as a radiation-polymerizable stripping solution) is an organic polysiloxane or polyalkylene oxide having a radiation-polymerizable functional group at a molecular end or a side chain. It is a mixture containing a modified acrylate as a main component and, if necessary, a photoinitiator and a sensitizer. An example of the radiation-polymerizable stripping solution used in the present invention is a silicone resin having a functional group selected from an acryloyl group, a methacryloyl group, a vinyl group and an epoxy group at a molecular end or a side chain. Application publication No. Sho 51-42961, Sho 54-6512, Sho 57-5
There are compounds such as those disclosed in 7096 and Sho 58-53656.

The photoinitiator used in the present invention, particularly when using the ultraviolet curing method, includes acetophenones such as di- and trichloroacetophenone, benzophenone, Michler's ketone, benzyl, benzoin, benzoin alkyl ether, benzyl dimethyl ketal, and tetramethyl thiuram mono. There are sulfides, thioxanthones, azo compounds, etc., and they are selected from the viewpoints of the type of polymerization reaction of the ultraviolet polymerizable resin and the ultraviolet polymerizable stripping solution, stability, and suitability with an ultraviolet irradiation device. The amount of the photoinitiator used is usually in the range of 0.1 to 5% with respect to the UV polymerizable resin or the UV polymerizable stripping solution. Further, a storage stabilizer such as hydroquinone may be used in combination with the photoinitiator.

Similarly, as the sensitizer used in the present invention, an aliphatic amine, an amine containing an aromatic group, a nitrogen heterocyclic compound, an allyl urea, O-tolylthiourea, sodium diethyldithiophosphate, a soluble salt of aromatic sulfinic acid, N,
There are N-disubstituted-P-aminobenzonitrile compounds, tri-n-butylphosphine, sodium diethylthiophosphate, Michler's ketone, N-nitrosohydroxylamine derivatives, oxazoline compounds, carbon tetrachloride, hexachloroethane, etc., and photoinitiators. Generally, it is possible to improve the curing speed by sharing with.

As the substrate used in the present invention, synthetic resin film such as glassine paper, high-quality paper, coated paper, polyethylene, polypropylene, polyethylene terephthalate, polyamide, or laminated paper in which these synthetic resins are laminated on one side or both sides, metal Examples include foil or metal foil and paper, and a laminated product of synthetic resin film.

The basis weight of the paper and film substrate is 5 to 250 g / m ² ,
It is more preferably 10 to 200 g / m ² , and the surface is preferably smooth, but a rough surface may be used for the control of peeling performance.

Before applying the radiation-polymerizable composition onto the substrate, the surface of the substrate may be subjected to surface treatment such as corona discharge.

A method for manufacturing a release sheet according to the present invention will be described with reference to the drawings.

FIG. 1 is a schematic view showing a cross section of a release sheet according to the present invention.

A release sheet 4 is formed by providing a primer layer 2 made of a radiation-polymerizable composition on a paper or film substrate 1 and further providing a release layer 3 coated by a free-fall vertical curtain on the primer layer 2.

FIG. 2 is a schematic view showing an example of a method for manufacturing the peeling sheet 4 according to the present invention.

The substrate 1 is unrolled from the supply roll 5, the primer layer 2 is coated by the coater 6, and the stripping solution 7 is coated on the substrate 1 by the coating head 8 as a free-fall vertical curtain 9.
It is cured by the radiation irradiation device 10. The primer layer 2 may be pre-cured by the radiation irradiation device 11 in advance. Further, the base 1 and the pre-cured primer layer 2 may be subjected to corona treatment by the corona generators 12 and 13. The peeling sheet 4 thus manufactured is a winding roll.
It is rolled up to 14.

FIG. 3 is a schematic view showing an example of the stripping solution coating method of the manufacturing method of the present invention.

The stripping solution 7 adjusted in advance is delivered from the stripping solution tank 15 to the coating head 8 by the delivery pump 16. It is preferable to use a non-pulsating constant flow rate pump as the liquid feed pump 16 to make the liquid feed to the coating head 8 constant and to keep the coating amount steady. The stripping liquid 7 sent to the coating head 8 stays in a chamber 17 in the coating head, and then forms a free-fall vertical curtain 9 and flows out from a slit 18 which is processed with high precision. At this time, the amount of liquid sent to the chamber 17 and the amount of liquid flowing out by forming the free-fall vertical curtain 9 are completely balanced (dynamic equilibrium state).
The liquid level of the peeling liquid 7 in 17 is kept constant. Guide rods 19 for supporting the liquid film of the free-fall vertical curtain 9 are provided at both ends of the liquid film. The opening width of the slit 18 is 0.05 mm
Suitably it is from 2.0 mm to 2.0 mm, preferably from 0.2 mm to 0.6 mm.

The free-falling vertical curtain 9 of the stripper 7 collides with the paper or film substrate 1 continuously running vertically under the curtain and is applied onto the substrate 1 (more precisely, the primer layer 2). The width of the free-fall vertical curtain 9 is sufficiently larger than the width of the substrate 1, and the stripping solution 7 that has fallen out of the width of the substrate 1 passes through the filter 21 recovered in the recovery tank 20 and then enters the stripping solution tank 15. It is sent again. As described above, by making the width of the free-fall vertical curtain 9 larger than the width of the substrate 1, thick coating of the coating liquid, which is likely to occur at both ends of the substrate 1, can be prevented and uniform coating can be performed. A windbreak plate 22 is provided on the front side of the free-fall vertical curtain 9 to prevent the liquid film of the free-fall vertical curtain 9 from being disturbed by the turbulence of the surrounding air flow. Further, the traveling direction of the substrate 1 is also changed just before the collision portion with the free-fall vertical curtain 9 so as not to cause turbulence of the air flow.

As described above, in the production method of the present invention, since the stripping solution 7 does not disturb the coated surface by the roll, the blade, or the air knife after coating, the primer layer 2 provided on the substrate 1 is not mixed. As a result, the performance as a peeling sheet is not lowered due to the reduction in peeling force. Further, the coating amount of the stripping liquid 7 is determined only by the ratio of the liquid feeding amount and the traveling speed of the substrate 1,
Since it is not necessary to scrape a certain amount or more after applying an excessive amount like a roll, a blade, or an air knife coating method,
It has excellent high-speed coating properties and thin-film forming properties.

According to the method of the present invention, the release layer is always coated on the primer layer during the process of manufacturing the release sheet and is not directly coated on the paper substrate. Absent. Therefore, the amount of expensive stripping solution can be reduced. Further, it has an advantage that a peeling liquid having a low viscosity can be used.

As shown in the present invention, when a radiation-polymerizable primer layer and a radiation-polymerizable release layer are superposed and simultaneously cured by irradiation with radiation, copolymerization occurs at the interface, and the adhesion between the primer layer and the release layer is very strong. Becomes Since the adhesion between the paper substrate and the primer layer such as various acrylates is generally very strong, as a result, a release sheet free from rub-off can be obtained by using the method of the present invention.

Examples of the method for applying the primer layer on the substrate include blade coating, air doctor coating, squeeze coating, air knife coating, reverse roll coating,
Methods such as gravure roll and transfer roll coating are used. As a matter of course, the free-fall vertical curtain method used when applying the stripper 7 may be used.

The amount of the primer layer to be applied onto the substrate are different 0.1 to 10 g / m ² depending on the type of substrate, more preferably 0.2-5 g / m ^2, the amount of release liquid (silicone composition) 0.1 g / m ² ~ 5g /
m ² , more preferably 0.5 to 5 g / m ² . The amount of stripper
If it is extremely small, 0.1 g / m ² or less, it is difficult to apply it uniformly on the primer layer, and peeling is deteriorated. Further, even if the amount of the peeling liquid is increased to 5 g / m ² or more, the property does not change and only the cost is improved. Further, if the amount is extremely large, the peeling layer is likely to fall off due to abrasion after curing.

As the electron beam irradiation conditions used in the present invention, the electron beam characteristics are the accelerating voltage of 50 to 750 KV in terms of penetrating power and curing power.
It is more preferable to use an electron beam accelerator of 100 to 300 KV so that the absorbed dose in one pass is 0.1 to 20 Mrad.

The electron beam accelerator may be, for example, an electro curtain system, a scanning type, a double scanning type, or the like.

In addition, when the electron beam is irradiated with a high oxygen concentration, the curing of the electron beam-polymerizable primer layer and the release layer is hindered, so nitrogen, helium, carbon dioxide, or another inert gas is substituted, and the oxygen concentration is 600 ppm or less. , Preferably 400p
Irradiation is preferably performed in an atmosphere suppressed to pm or less.

Examples of the ultraviolet irradiation device used in the present invention include a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, a metal halide lamp, and the like, and an ozoneless type that generates less ozone. Generally, multiple lamps with an output of 30w / cm or more are used in parallel.

The height of the free-fall vertical curtain in the present invention varies depending on the supply amount of the stripping solution (it varies depending on the coating amount and the coating speed), but is usually 40 cm or less, preferably 30 cm or less, particularly preferably 5 to 20 cm or so. Is.

It is needless to say that the present invention is not limited to the above-mentioned embodiment and various modifications can be made. For example, the coating head 8 has been described only for the extrusion coating type vertical type head, but the coating head 8 is not limited to this type, and the curtain coating type slide type and non-slide type, The present invention also includes the case of using a non-slide hopper type, a slide hopper type, and the like, of the rouge coating method. As a matter of course, when using the extrusion coating slide type, the bead (bridge length) is about 10 μm to 500 μm.

There is also a method in which preliminary radiation is applied in advance to partially cure the surface of the primer layer, and then a release liquid is applied by a free-fall vertical curtain, and secondary irradiation is performed to completely cure the primer layer to form a release layer. In this case, the economical efficiency is significantly inferior to the method of completely curing with one irradiation, but in the case of coating at a high speed of 1000 m / min or more, which is possible in the case of the curtain coating method, the uncured primer is used. It is possible to avoid the deterioration of the surface smoothness due to the vibration of the layer, and it is possible to take full advantage of forming a thin film of the stripping solution on the primer layer as a stopper for the stripping solution.

[E] Action In the present invention, in the production of a release sheet, after applying a radiation-polymerizable primer layer having good adhesiveness to a substrate on a release substrate, a radiation-polymerizable release liquid is applied by a free-fall vertical curtain, A release sheet is produced by curing by irradiation with radiation. Since the base material is sealed by the primer layer, not only the release liquid does not soak into the base material,
A stripping sheet having good strippability can be formed without the mixing of the stripping solution and the primer layer during coating and curing. Further, by using a primer layer having good adhesion to the substrate between the substrate and the electropolymerizable release layer, polymerization is performed between the primer layer and the release layer. Therefore, the adhesiveness between the release layer and the substrate is significantly improved. Further, since the high temperature treatment is not performed in the manufacturing process, it is possible to suppress the occurrence of curls, wrinkles, pinholes in the release layer and the like due to the high temperature treatment.

[F] Examples Hereinafter, the present invention will be described in detail with reference to Examples, but the contents of the present invention are not limited to the Examples.

Example-1 Corona treatment was applied to one side of a fine paper substrate having a basis weight of 90 g / m ² using an alkyl ketene dimer as a sizing agent running at 150 m / min, and trimethylolpropane was used as a primer layer using a gravure coater. Triacrylate (product of Toa Gosei Chemical Industry Co., Ltd., trade name Aronix M
-309) at a coating amount of ² g / m ^{2 and then} the width 50 shown in FIG.
mm with a free-fall vertical curtain coating device having a slit width of 0.5 mm, and coated with an electron beam polymerizable silicone resin (Shin-Etsu Chemical Co., Ltd., trade name X-62-7177) at a coating amount of 0.6 g / m ^2. did. The sheet thus obtained is introduced into an electron beam irradiation device (ESI, trade name Electro Curtain, TYPE: CB200 / 45/300) in which the oxygen concentration in the electron beam irradiation chamber has been reduced to 200 ppm or less by nitrogen gas replacement. , Electron beam acceleration voltage d00
The peeling sheet was obtained by irradiating with an electron beam so that the absorbed dose was 4 Mrad under the conditions of kV and irradiation current of 20 mA.

Example-2 In the same coating method as in Example-1, 2 g / m ² of polyethylene oxide diacrylate (product of Toagosei Kagaku Kogyo KK, trade name Aronix M-245) was coated as an electron beam polymerizable primer layer. Absorbed dose 1Mra
After irradiating with an electron beam so as to be d and performing corona treatment again, an electron beam polymerizable silicone resin (Shin-Etsu Chemical Co., Ltd., trade name X-
62-7168) with an application amount of 0.6 g / m ² and an absorbed dose of 3 Mrad
To obtain a peeling sheet.

Example-3 In the same coating method as in Example-1, 2% benzyl dimethyl ketal (product of Ciba-Geigy Co., Ltd., product name Irgacure 651) as a photopolymerization initiator for the electron beam polymerizable primer layer, and UV-polymerizable primer Isocyanuric acid diacrylate as a layer (Toagosei Chemical Industry Co., Ltd.)
The product, trade name Aronix M-215) is applied at a coating amount of ² g / m ² and then the UV-curable silicone resin (Shin-Etsu Chemical Co., Ltd.) is used by the free-fall vertical curtain coating method. , Product name KNS50002) 0.6g / m ²
And the coating amount. The sheet thus obtained is then irradiated with an ultraviolet irradiation device (80 W / cm, ozone condensing type, irradiation distance 10 c
m) and irradiated with ultraviolet rays to obtain a peeling sheet.

Example 4 A polyethylene terephthalate film having a basis weight of 100 g / m ² as a substrate (Mitsubishi Resins Co., Ltd., trade name Diafoil # 10)
(0) was applied to one side of the surface by corona treatment, and an electron beam polymerizable primer layer as shown below was applied at a coating amount of ² g / m ² using a gravure coater while running at 150 m / min. N
-Vinyl-2-pyrrolidone M-150, 30 parts, acrylate monomer M-309, 70 parts (both manufactured by Toagosei Kagaku Kogyo Co., Ltd.) Next, using the free-fall vertical curtain coating method as Example-1 A similar electron beam-polymerizable silicone resin was applied at a coating amount of 0.5 g / m ² , followed by electron beam irradiation and curing under the same conditions as in Example-1 to obtain a release sheet.

Comparative Example-1 The same high quality paper as in Example-1 was subjected to corona treatment and directly applied without applying an electron beam polymerizable primer layer.
An electron beam-polymerizable silicone composition similar to that of No. 1 was applied and cured by the same electron beam irradiation as in Example-1. The resulting release sheet was a paper in which most of the silicone resin had soaked into the paper.

Comparative Example-2 In the same manner as in Example-1, the fine paper running at 150 m / min was subjected to corona treatment, the electron beam polymerizable primer layer was applied using a gravure coater, and the same electron beam polymerization as in Example-1 was applied. The photosensitive silicone composition was applied using offset gravure, and cured by the same electron beam irradiation as in Example-1. The obtained release sheet was a product in which the silicone resin and the primer layer were mixed and the release property was lowered.

Comparative Example-3 Using a polyethylene terephthalate film traveling at 150 m / min similar to Example-3, after subjecting one side to corona treatment, a free-fall vertical curtain coating method was applied without applying an electron beam polymerizable composition. The same electron beam-polymerizable silicone composition as in Example-1 was applied using the composition and cured by the same electron beam irradiation as in Example-1 to obtain a release sheet. The obtained release sheet had insufficient adhesion between the release layer and the substrate, and was likely to cause a rub-off.

Comparative Example-4 Using a polyethylene terephthalate film traveling at 150 m / min in the same manner as in Example-3, after subjecting one side to corona treatment, and using a gravure coater, an electron beam polymerizable primer layer similar to that in Example-3 Was applied, and the same electron beam-polymerizable silicone composition as in Example-1 was applied using an air knife, and cured by the same electron beam irradiation as in Example-3. The obtained release sheet was a product in which the silicone resin and the primer layer were mixed and the release property was lowered.

Comparative Example-5 The same high-quality paper as in Example-1 was subjected to corona treatment to obtain a thermosetting silicone resin (Shin-Etsu Chemical Co., Ltd., trade name KN).
S, platinum catalyst CAT PL-8 included) was applied so that the silicone weight would be 0.6 g / m ^{2 in} the dry state. The sheet thus obtained was heated and cured in a dryer at 150 ° C. for 50 seconds. The resulting release sheet was a paper in which most of the silicone resin had soaked into the paper.

Table 1 shows the results of the peeling resistance values with respect to the pressure-sensitive adhesive, the residual adhesion ratio, rub-off, curl, wrinkles, and pinholes of the peeling sheets obtained in the above Examples and Comparative Examples.

The test method is as follows.

[Peel strength] Adhesive on high-quality paper (manufactured by Toyo Ink Co., Ltd., product name BP
S) was applied and used as a standard adhesive sheet. Obtain the release paper and release sheet (width 25 mm) at 20 ° C and humidity 65%
After being left in a constant temperature and humidity chamber for 24 hours, pressure-bonded to a standard adhesive sheet with a pressure roller of 2000 g and left in a constant temperature and humidity chamber at 20 ° C and a humidity of 65% for 2 hours, then Tensilon (Toyo Baldwin Co., Ltd.) The peel strength is defined as the load when peeled continuously under the conditions of a peel angle of 180 ° and a peel speed of 30 cm / min.

[Residual Adhesion Rate] The obtained release sheet (width 25 mm) was left in a thermo-hygrostat at 20 ° C and a humidity of 65% for 24 hours, and then pressure-bonded to a standard pressure-sensitive adhesive sheet with a pressure-bonding roller weighing 2000 g at 20 ° C. Humidity 65%, pressure
Pressure was applied for 24 hours under the condition of 0.1 kg / cm ² . After peeling the standard adhesive sheet from the release sheet, the surface is well polished to a thickness 1.
It is attached to a 5 mm stainless steel plate, pressure-bonded with a pressure roller of 2000 g, and left for 1 hour in a thermo-hygrostat at 20 ° C and a humidity of 65%. Then, it is continuously peeled off with a tensilon at a peeling angle of 180 ° and a peeling speed of 30 cm / min. The load when peeled off is obtained as the peel strength. Next, a standard pressure-sensitive adhesive sheet was attached to a stainless steel plate having a well-polished surface and a thickness of 1.5 mm, and pressure was applied for 24 hours under the conditions of 20 ° C., humidity 65%, and pressure 0.1 kg / cm ² . After returning the pressure to normal pressure, press it with a pressure roller with a weight of 2000g and press it at 20 ℃ and humidity of 65.
% After being left for 1 hour in a thermo-hygrostat, the load when continuously peeling with Tensilon at a peeling angle of 180 ° and a peeling speed of 30 cm / min is obtained as the peeling strength. Residual adhesion rate R
(%) Is calculated by the following formula. If the peel strength of the pressure-sensitive adhesive sheet after contacting the release sheet = A and the peel strength of the pressure-sensitive adhesive sheet not in contact with the release sheet = B, then R = (A /
B) × 100 [lab-off] The silicone surface of the release sheet was rubbed strongly with a finger, and the release of the silicone surface was visually determined.

[Pinhole] The silicone surface of the release sheet was wetted with toluene in which a dye was dissolved, and the penetration condition was observed from the back surface.

[Curl and wrinkle] It was judged by relative comparison under the conditions of 20 ° C and humidity of 65%.

[G] Effect of the Invention Table 1 shows the results of the peeling resistance values with respect to the pressure-sensitive adhesive, the residual adhesion ratio, the rub-off, curl, wrinkles and pinholes of the peeling sheets prepared in Examples and Comparative Examples.
As is clear from Table 1, the peeling sheets obtained in Examples-1, 2, 3, and 4 have a small peel strength and a large residual adhesion rate. Furthermore, since it is not subjected to high-temperature heat treatment, it has excellent characteristics without curling, wrinkles, and pinholes.
On the other hand, even if the same electron beam-polymerizable silicone composition is used, as in Comparative Example-1, the one having no undercoat layer of the electron beam-polymerizable composition has the silicone resin soaked into the paper substrate,
As a result, the peel strength is increased, and the number of pinholes is extremely large due to the poor film forming property of the silicone resin. Comparative Example-2
The peeling sheet obtained by the above-mentioned method has almost the same drawbacks as the peeling sheet of Comparative Example-4, and mixing at the time of coating the primer layer and the peeling layer occurs, and the peelability is lowered. Regarding the release sheet obtained in Comparative Example 3, the adhesion between the release layer and the polyethylene terephthalate film was poor,
It has a drawback that the peeling layer causes a phenomenon of so-called love-off in which the peeling layer peels off by friction. In Comparative Example-5, most of the release layer penetrated into the substrate and the release property was poor, and curling and wrinkling due to heating were also observed.

As described above, according to the method of the present invention, it is possible to produce a peeling sheet that does not cause curling, wrinkling, pinholes, etc., has excellent adhesiveness to various substrates, and does not cause a rub-off phenomenon in a small number of steps.

[Brief description of drawings]

FIG. 1 is a schematic view showing a cross section of the release sheet of the present invention. FIG. 2 is a schematic view showing an example of a method for producing a release sheet of the present invention. FIG. 3 is a schematic view showing an example of the stripping solution coating method of the manufacturing method of the present invention. 1: substrate, 2: primer layer, 3: release layer, 4: release sheet, 5: supply roll, 6: coater, 7: release liquid, 8: coating head, 9: free-fall vertical curtain, 10, 11: Radiation irradiation device, 12, 13: Corona generator, 14: Take-up roll, 15: Stripping liquid tank, 16: Liquid feeding pump, 17: Chamber, 18: Slit, 19: Guide rod, 20: Recovery tank, 21: Filter, 22: windbreak

Claims (2)

[Claims] 1. A release sheet having a release layer on at least one surface of a paper or film substrate, which has a primer layer of a coating liquid containing a radiation-polymerizable resin having good adhesiveness with the substrate on the substrate. , Further having a layer of a stripping solution mainly composed of a radiation-polymerizable composition having a releasability after curing applied by a free-fall vertical curtain, and both layers being cured by irradiation with radiation. A peeling sheet characterized by being present. 2. A method for producing a release sheet having a release layer on at least one side of a paper or film substrate, wherein a substrate treated with a coating solution containing a radiation-polymerizable resin having good adhesiveness to the substrate as a main component is treated. , Radiation-polymerizable and continuously traveling so as to cross a free-falling vertical curtain of a layer of a stripping solution mainly composed of a composition having a strippability after curing, and coating the strippable composition on the substrate, After that, both layers of the release layer and the primer layer are simultaneously cured by irradiation of radiation, which is a method for producing a release sheet.