JPH082619B2 - Release sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [A] Field of Industrial Application The present invention provides a layer on a sheet-like substrate such as paper, laminated paper, synthetic paper, and plastic film, which has excellent blocking resistance and excellent internal peeling prevention property. The present invention relates to a peeling sheet provided with.

[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 forming a cured coating by heating at 1.

[C] Problems to be Solved by the Invention It is needless to say that heat resistance of a paper base is required when such a high-temperature heat treatment is applied to a release sheet using a paper base, and in addition, evaporation of water inside the paper base Therefore, there are drawbacks that wrinkles and curls are easily generated, and pinholes are easily generated in the release layer due to water evaporation. 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 surface of the laminate substrate, which hinders peeling performance, and pinholes are generated due to the generation of bubbles due to water evaporation in the paper. It had the drawback of being easy. As one means for overcoming such drawbacks, a solventless silicone resin, particularly a silicone resin having a functional group capable of being polymerized by irradiation with ultraviolet (UV) and electron beam (EB), is used for UV or EB curing. A low-temperature curing type release paper manufacturing technology has been developed. 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, a silicone film prepared by a low temperature curing type method of performing UV or EB curing has a problem that it has poor adhesion to a film substrate.

[D] Means for Solving Problems The inventors of the present invention have found the following methods as a result of earnest research on means for solving the above problems.
That is, an electron beam polymerizable composition layer having good adhesiveness to the substrate is coated on at least one surface of a paper or film substrate, and a composition layer that is electron beam polymerizable and has releasability after curing is further applied thereon. It has been found that a release sheet that solves the above problems can be obtained by providing a layer in which both layers are simultaneously cured by electron beam irradiation after application, and completed the present invention. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. In the present invention, an electron beam curable resin layer having good adhesiveness to a substrate and an electron beam curable resin layer having good adhesiveness and releasability are sequentially provided on a substrate for electronic irradiation. The release sheet prepared by the above is provided. The electron beam polymerizable composition having good adhesion to the substrate (hereinafter simply referred to as electron beam polymerizable composition) is a compound having an acroyl group or a methacryloyl group.

As the electron beam polymerizable composition used in the present invention, unsaturated polyester having a reactive group at a molecular end or in a molecular side chain, modified unsaturated polyester, an acrylic polymer and a monomer having an unsaturated bond are simple substances. Although it can be used together with other solvents, it is selected in consideration of the affinity between the substrate and the electron beam polymerizable composition, and the affinity between the electron beam polymerizable composition and the electron beam polymerizable silicone composition. Hereinafter, typical compounds among the compounds constituting the electron beam 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,
Viscoat 540 (Osaka Organic Chemical Industry Co., Ltd. product name), Photomer 3016, Photomer 3082 (or San Nopco Ltd. product name) (c) Urethane acrylate, ureta 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, etc. Ethylene oxide modified phenoxyphosphoric acid acrylate Ethylene oxide modified butoxylated phosphoric acid acrylate, etc. The product name of Aronix M-101, Aronit Scan M-102, Aronix M-11
1, Aronix M-113, Aronix M-114, Aronix M-117, Aronix M-152, Aronix M-154 and the like.

(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.

The composition having releasability after curing is an organic polysiloxane having an electron beam polymerizable functional group at a molecular end or a side chain (hereinafter, simply referred to as an electron beam polymerizable silicone composition). The electron beam polymerizable silicone composition used in the present invention is a silicone resin having a functional group selected from an acryloyl group, a methacryloyl group and a vinyl group at a molecular end or a side chain. Specifically, the patent application publication 51-42961, 54-1652, 57-57096, 58-
The compounds are disclosed in, for example, Japanese Patent No. 53656.

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 This refers to a laminated product of foil or metal foil and paper or synthetic resin film.

The basis weight of the paper substrate is 40 to 250 g / m ² , more preferably 5
It is 0 to 200 g / m ² , and its surface is preferably smooth, but it may be a rough surface for the control of peeling performance.

Before applying the electron beam polymerizable composition onto the substrate, the substrate surface may be subjected to surface treatment such as corona discharge.

 The peeling sheet according to the present invention will be described with reference to the drawings.

FIG. 1 is a schematic side view showing an example of a peeling sheet manufactured by the method of the present invention.

The electron beam polymerizable composition 2 serves as a sealing layer on the base sheet 1 to prevent the electron beam polymerizable silicone composition 3 from seeping into the base sheet 1.

FIG. 2 is a schematic side view showing an example of a peeling sheet manufacturing apparatus used for carrying out the present invention.

The substrate sheet 1 is unrolled from the supply roll 4, the electron beam polymerizable composition 2 is applied by the coater 5, the electron beam polymerizable silicone composition 3 is applied by the coater 6, and then the electron beam is irradiated by the electron beam irradiation device 7. The electron beam polymerizable composition 2 and the electron beam polymerizable silicone composition 3 are cured. The peeling sheet 8 manufactured in this manner is wound up by the winding roll 9. The base sheet 1
The surface of may be subjected to corona treatment by the corona generating device 10.

According to the method of the present invention, the silicone resin is always coated on the electron beam polymerizable composition and not directly on the paper substrate during the release paper manufacturing process, so that the silicone resin is not soaked into the paper substrate. Absent. Therefore, the amount of expensive silicone resin can be reduced. It also has the advantage that a low concentration of silicone resin can be used.

As shown in the present invention, when the electron beam polymerizable composition and the electron beam polymerizable silicone composition are overlapped and simultaneously cured by electron beam irradiation, copolymerization occurs at the interface, resulting in the electron beam polymerizable silicone composition layer and the electron beam. The adhesion with the polymerizable composition layer becomes very strong. Since the adhesion between the paper substrate and the electron beam polymerizable composition such as various acrylates is generally very strong, as a result, the release sheet free from silicone release can be obtained by using the method of the present invention.

Examples of the method for applying the electron beam polymerizable composition and the electron beam polymerizable silicone composition on the substrate include blade coating, air doctor coating, squeeze coating, air knife coating, reverse roll coating, gravure roll and transfer roll coating. , E-bar coat, etc. are used.

The amount of the electron beam polymerizable composition applied on the substrate varies depending on the type of the substrate, but 0.1 to 10 g / m ² , more preferably 0.2 to 5 g / m ² .
² and the amount of electron beam polymerizable silicone composition is 0.1 g / m ² ~
5 g / m ^2, more preferably from 0.5 to 5 g / m ^2. If the amount of the silicone composition is extremely small as 0.1 g / m ² or less, it is difficult to apply it uniformly on the electron beam polymerizable composition, and peeling is deteriorated, and the amount of silicone is 5 g / m ² or more. Even if the amount is increased, the property does not change, and only the cost is improved. Further, if the amount is extremely increased, the silicone is likely to fall off due to abrasion after curing.

When the surface of the release paper is further mirror-finished, the surface to be treated can be brought into contact with a mirror-finish roll and irradiated with an electron beam from the back side of the roll for curing to effect mirror-finish. Although it is significantly less economical than the method of completely curing with one-time irradiation, preliminary electron beam irradiation is performed in advance to partially cure the surface, contact with a mirror surface roll, peeling, and secondary irradiation to complete And a method of curing the electron beam polymerizable composition on the substrate, and after the first electron beam irradiation to cure the electron beam polymerizable composition, the electron beam polymerizable silicone composition is applied. There is also a method of forming a release layer by performing secondary irradiation.

When applying a mold, a desired mold surface such as a finely roughened surface can be obtained by using a mold roll instead of the mirror surface roll.

As the electron beam characteristics, the accelerating voltage is 50 to 750 Kv in terms of penetrating power and curing power, more preferably using an electron beam accelerator of 100 to 300 Kv, and the absorbed dose in one pass can be set to 0.1 to 20 Mrad. preferable.

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 irradiating with an electron beam, if the oxygen concentration is high, the curing of the electron beam polymerizable composition is hindered, so nitrogen, helium, substitution with an inert gas such as carbon dioxide is performed, and the oxygen concentration is 600 ppm or less, preferably 400 ppm. The irradiation is preferably performed in an atmosphere controlled as follows.

[E] Action In the present invention, in the production of a release sheet, an electron beam polymerizable silicone composition having good adhesion to a substrate is applied onto a release substrate, and then an electron beam polymerizable silicone composition is applied to the electron beam polymerizable silicone composition. It is cured by irradiation to produce a release sheet,
Since the substrate is sealed with the electron beam polymerizable composition, the silicone resin does not penetrate into the substrate. Further, by using an electron beam polymerizable composition having good adhesiveness to the substrate between the substrate and the electron beam polymerizable silicone resin layer, polymerization between the electron beam polymerizable composition and the electron beam polymerizable silicone composition is achieved. Done. Therefore, the adhesion between the silicone resin layer and the substrate is remarkably 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, etc. in the silicone resin layer, which are caused by 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 performed on one surface of a high-quality paper having a basis weight of 90 g / m ² using an alkyl ketene dimer as a sizing agent for a substrate, and isocyanuric acid diacrylate was used as an electron beam polymerizable composition using a gravure coater (Toagosei Co., Ltd.). Chemical Industry Co., Ltd. product, trade name Aronix M-215, was applied at a coating amount of ² g / m ² and then electron beam curable silicone resin (Shin-Etsu Chemical Co., Ltd. trade name, X-) using a gravure coater. 62-716
8) was applied at a coating amount of 0.6 g / m ² . The thus obtained sheet is introduced into an electron beam irradiation device (made by 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 substitution. The electron beam irradiation was performed so that the absorbed dose was 4 Mrad under the conditions of an electron beam acceleration voltage of 175 Kv and an irradiation current of 20 mA. Table 1 shows the results of the peeling resistance value with respect to the adhesive, the residual adhesion ratio, the rub-off, the curl, the wrinkles, and the presence of pinholes of the obtained release sheet.

Example-2 In the same manner as in Example-1, only the electron beam polymerizable composition was treated with 2-hydroxylethyl acrylic phosphate (Kyoeisha Oil and Fat Chemical Co., Ltd., trade name Light Ester PA).
Was changed to a coating amount of 1.5 g / m ² and the other conditions were the same to produce a release sheet.

Table 1 shows the results of the peeling resistance value with respect to the adhesive, the residual adhesion ratio, the rub-off, the curl, the wrinkles, and the presence of pinholes of the obtained release sheet.

Example-3 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), corona treatment was applied to one side, and 2 g / m ^{2 of} electron beam polymerizable composition as shown below was obtained using a gravure coater.
Was applied at the application amount.

Epoxy-modified acrylate TO-458 30 parts, acrylate monomer M-5700 70 parts (both are products of Toa Gosei Kagaku Kogyo Co., Ltd.) Next, an electron beam curable silicone resin similar to that of Example-1 was prepared using a gravure coater. After coating with a coating amount of 0.6 g / m ² , electron beam irradiation was performed under the same conditions as in Example-1 to cure, and a release sheet was obtained.

Table 1 shows the results of the peeling resistance value with respect to the adhesive, the residual adhesion ratio, the rub-off, the curl, the wrinkles, and the presence of pinholes of the obtained release sheet.

Comparative Example-1 The same high-quality paper as in Example-1 was subjected to corona treatment, and the same electron beam-polymerizable silicone composition as in Example-1 was directly applied without applying the electron beam-polymerizable composition. Example-
Curing was performed by the same electron beam irradiation as in 1. 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 with respect to the pressure-sensitive adhesive, the residual adhesion ratio, the rub-off, the curl, the wrinkle, and the presence or absence of pinholes for this release sheet.

Comparative Example-2 The same polyethylene terephthalate film as in Example-3 was used, and after corona treatment was applied to one side, the same electron as in Example-1 was obtained using a gravure coater without applying the electron beam polymerizable composition. A ray-polymerizable silicone composition was applied and cured by the same electron beam irradiation as in Example-1. Table 1 shows the results of the peeling resistance value with respect to the adhesive, the residual adhesion ratio, the rub-off, the curl, the wrinkles, and the presence of pinholes of the obtained release sheet.

Comparative Example-3 The same high-quality paper as in Example-1 was subjected to corona treatment, and 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 drier at 140 ° 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 with respect to the pressure-sensitive adhesive, the residual adhesion ratio, the rub-off, the curl, the wrinkle, and the presence or absence of pinholes for this release sheet.

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 and 3 have a small peel strength and a high residual adhesion rate.
Curling, wrinkling, and
It has excellent characteristics without pinholes. On the other hand, even if the same electron beam-polymerizable silicone composition was used, as in Comparative Example 1, in the case where the electron beam-polymerizable composition was not used as the undercoat layer, the silicone resin soaked into the paper substrate, resulting in increased peel strength. There are very many pinholes because the film forming property of the silicone resin is poor. The peeling sheet obtained in Comparative Example 3 has almost the same drawbacks as the peeling sheet in Comparative Example 2, and the curls and wrinkles due to the high-temperature heat treatment are remarkable. The peeling sheet obtained in Comparative Example 2 had a drawback that the adhesion between the silicone resin and the polyethylene terephthalate film was poor and the silicone resin caused a so-called "lab-off" phenomenon of peeling due to friction.

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 side view showing an example of the peeling sheet of the present invention. FIG. 2 is a schematic side view showing an example of the release sheet manufacturing apparatus of the present invention. 1: base sheet, 2: electron beam polymerizable composition, 3: electron beam polymerizable silicone composition, 4: supply roll, 5: coater, 6: coater, 7: electron beam irradiation device, 8: release sheet, 9: Take-up roll, 10: Corona generator.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B32B 27/16 8413-4F

Claims (2)

[Claims] 1. An electron beam polymerizable composition layer having an acryloyl group or a methacryloyl group and containing no organic polysiloxane is coated on at least one surface of a paper or film substrate, and further electron beam polymerizable, A peeling sheet, which is produced by applying a composition layer having releasability after curing and then simultaneously curing both layers by electron beam irradiation. 2. A composition which is polymerizable by electron beam and has releasability after curing has an organic group having a functional group selected from an acryloyl group, a methacryloyl group and a vinyl group at a molecular end or a side chain. The release sheet according to claim 1, which is made of polysiloxane.