JP4523780B2 - Release sheet - Google Patents

Description

  The present invention relates to a release sheet. More specifically, the present invention is non-silicone, has good peelability from the pressure-sensitive adhesive layer, has excellent adhesion between the release agent layer and the substrate, and is suitable for applications related to precision electronic equipment. The present invention relates to a release sheet used.

  In recent years, pressure-sensitive adhesive sheets have been used in various stages and types of manufacturing processes for precision electronic devices such as ceramic capacitors, hard disk drives, and semiconductor devices.

In such a pressure sensitive adhesive sheet used in the manufacturing process of precision electronic equipment, the silicone pressure sensitive adhesive may cause trouble with electronic components due to the low molecular weight silicone compound contained in the pressure sensitive adhesive. For example, an acrylic adhesive, a polyester adhesive, a urethane adhesive, or the like is used.
In order to protect the pressure-sensitive adhesive layer until use, this pressure-sensitive adhesive sheet is laminated with a release sheet provided with a release agent layer on a substrate.

In the release sheet of the release sheet, a silicone release agent is often used for general purposes. When a silicone release agent is used for the above use, a low molecular weight silicone compound contained in the release agent is used. Migrates and remains in the pressure-sensitive adhesive layer, and there is a possibility that the electronic component may cause trouble in the same manner as the silicone-based pressure-sensitive adhesive.
Therefore, in the release agent layer of the release sheet used for the above-mentioned application, an alkyd resin known as a non-silicone release agent (for example, see Patent Document 1) or a long chain alkyl resin (for example, Patent Document 1) 2) has been attempted.

  However, when these resins are used for the release agent layer, there is a problem that the release force from the adhesive layer is high and the adhesive layer and the release agent layer may not be released.

Japanese Unexamined Patent Publication No. 57-49585 JP 2002-249757 A

  Under such circumstances, the present invention provides a release sheet that is non-silicone and has a release agent layer that is excellent in peelability from a pressure-sensitive adhesive layer, stability over time, and adhesion to a substrate. It is intended.

As a result of intensive research in order to achieve the above object, the present inventors applied a release agent solution containing 1,4-polybutadiene and an antioxidant on a substrate, and then cured by irradiating with ultraviolet rays. It was found that the purpose can be achieved by providing a release agent layer.
The present invention has been completed based on such findings.
That is, the present invention
(1) A release sheet comprising a release agent layer formed by coating a release agent solution containing 1,4-polybutadiene and an antioxidant on a substrate, and curing by applying ultraviolet rays;
(2) The release sheet of (1) above, wherein the irradiation amount of ultraviolet rays is 1 to 50 mJ / cm ² .
(3) The content of the antioxidant is 0.1 to 15 parts by weight based on 1,4-polybutadiene 100 parts by weight, the peeling sheet for the above (1) or (2),
(4) The release sheet according to any one of (1) to (3) above, wherein the coating amount of the release agent solution is 0.01 to 1.5 g / m ² as the weight of the solid content, and
(5) Any one of (1) to (4), wherein the base material is one selected from a paper base material, a laminated paper obtained by laminating a thermoplastic resin on a paper base material, a plastic film, and a laminated sheet containing these. Release sheet according to crab,
Is to provide.

  The peeling force between the release agent layer and the pressure-sensitive adhesive layer of the release sheet of the present invention is low, and the release stability over time and the adhesion to the substrate are also excellent.

  There is no restriction | limiting in particular as a base material in the peeling sheet of this invention, It can select suitably from well-known base materials conventionally known as a base material of a peeling sheet. Examples of such base materials include paper base materials such as glassine paper, coated paper, cast coated paper, and dust-free paper, laminated paper obtained by laminating a thermoplastic resin such as polyethylene on these paper base materials, polyethylene terephthalate, Examples thereof include polyester films such as butylene terephthalate and polyethylene naphthalate, polyolefin films such as polypropylene and polymethylpentene, plastic films such as polycarbonate films and cellulose acetate films, and laminated sheets containing these. Although there is no restriction | limiting in particular as thickness of this base material, Usually, 10-150 micrometers is desirable.

  When a plastic film is used as the substrate, for the purpose of improving the adhesion between the plastic film and the release agent layer, an oxidation method or A physical or chemical surface treatment such as an uneven method can be performed. Examples of the oxidation method include corona discharge treatment, chromic acid treatment, flame treatment, hot air treatment, ozone / ultraviolet irradiation treatment and the like, and examples of the concavo-convex method include a sand blast method and a solvent treatment method. . These surface treatment methods are appropriately selected according to the type of the substrate, but in general, the corona discharge treatment method is preferably used from the viewpoints of effects and operability. Moreover, primer treatment can also be performed.

The 1,4-polybutadiene used in the release agent solution for forming the release layer in the release sheet of the present invention is only from 1,4-bonds other than 1,2-bonds that are inevitably generated during polymerization. It is a polybutadiene composed.
Further, 1,4-polybutadiene may have either a cis structure or a trans structure, and those having an arbitrary cis content can be used.

In the present invention, the release agent solution contains an antioxidant.
The antioxidant is not particularly limited, and any of known phosphite antioxidants, organic sulfur antioxidants, hindered phenol antioxidants, and the like can be used.

  As phosphite antioxidants, those containing phosphite in the chemical structural formula, specifically, for example, Irgafos 38, Irgafos P-EPQ, Irgafos 126 (all of which are manufactured by Ciba Specialty Chemicals Co., Ltd.), Sumilizer TNP , Sumilyzer TPP-P, Sumilyzer P-16 (all manufactured by Sumitomo Chemical Co., Ltd.), ADK STAB PEP-4C, ADK STAB PEP-8, ADK STAB 11C, ADK STAB PEP-36, ADK STAB HP-11, ADK STAB 260, ADK STAB 522A, Examples include ADK STAB 329K, ADK STAB 1500, ADK STAB C, ADK STAB 135A, and ADK STAB 3010 (all manufactured by Asahi Denka Kogyo Co., Ltd.).

  Organic sulfur-based antioxidants containing thioethers in the chemical structural formula, specifically, for example, Irganox PS800FL, Irganox PS802FL (all of which are manufactured by Ciba Specialty Chemicals), Sumilyzer TP-M, Sumilyzer TP-D, Sumilizer TL, Sumilizer MB (all of which are manufactured by Sumitomo Chemical Co., Ltd.), ADK STAB AO-23 (manufactured by Asahi Denka Kogyo Co., Ltd.) and the like are listed. -Laurylthiopropionate) is preferred.

  As the hindered phenol-based antioxidant, those having a 2,6-alkylphenol in the chemical structural formula, specifically, for example, Irganox 245, Irganox 259, Irganox 565, Irganox 1010, Irganox 1035, Irga Knox 1076, Irganox 1098, Irganox 1222, Irganox 1330, Irganox 1425, Irganox 3114, Irganox 1520, Irganox 1135, Irganox 1141, Irganox HP2251 (all manufactured by Ciba Specialty Chemicals) , Sumilyzer BHT, Sumilyzer MDP-S, Sumilyzer GA-80, Sumilyzer BBM-S, Sumilyzer WX-R, Sumilyzer GM, Sumilyzer G (Above all manufactured by Sumitomo Chemical Co., Ltd.), ADEKA STAB AO-30 (Asahi Denka Co., Ltd.).

These antioxidants may be used individually by 1 type, and may be used in combination of 2 or more type.
Further, the amount used is preferably 0.1 parts by weight or more with respect to 100 parts by weight of 1,4-polybutadiene, from the viewpoint of suppressing heavy release due to deterioration of 1,4-polybutadiene. From the viewpoint of sufficiently maintaining the adhesion to the sheet substrate, the amount is preferably 15 parts by weight or less with respect to 100 parts by weight of 1,4-polybutadiene. That is, the amount of the antioxidant used is preferably in the range of 0.1 to 15 parts by weight with respect to 100 parts by weight of 1,4-polybutadiene.

The release agent liquid of the present invention is obtained by dissolving 1,4-polybutadiene, an antioxidant, and other components to be blended as necessary in an organic solvent.
The organic solvent used at this time can be appropriately selected from known solvents having good solubility in the blending components.
Examples of such a solvent include toluene, xylene, methanol, ethanol, isobutanol, n-butanol, acetone, methyl ethyl ketone, and tetrahydrofuran. These may be used individually by 1 type, and may be used in combination of 2 or more types.

For the convenience of coating, the release agent solution is preferably prepared using these organic solvents so that the solid content concentration is in the range of 0.5 to 15% by weight.
Coating of the release agent liquid on the substrate is conventionally known, for example, bar coating method, reverse roll coating method, knife coating method, roll knife coating method, gravure coating method, air doctor coating method, doctor blade coating method, etc. The coating method can be used.
The coating amount of the release agent solution is preferably 0.01 g / m ² or more as the weight of the solid content in order to obtain the required peeling force (light peeling), and in order not to cause blocking, The weight is preferably 1.5 g / m ² or less. That is, the coating amount of the release agent solution is preferably in the range of 0.01 to 1.5 g / m ² , particularly preferably in the range of 0.02 to 0.2 g / m ² as the weight of the solid content.

The release agent solution is applied onto the substrate, heated at a temperature of about 40 to 160 ° C. for 30 seconds to 1 minute, dried, then irradiated with ultraviolet rays to crosslink and cure the polybutadiene, and then peeled off. An agent layer is formed.
Conventionally known high-pressure mercury lamps, metal halide lamps, high-power metal halide lamps, electrodeless lamps, and the like can be used as the ultraviolet lamps used for ultraviolet irradiation, but electrodeless lamps are most suitable in terms of curability of polybutadiene.

The amount of UV irradiation is preferably 1 mJ / cm ² or more from the viewpoint of obtaining high adhesion between the release sheet substrate and the release agent, and 50 mJ / cm ² from the viewpoint of obtaining light release from the silicone release agent. The following is preferred. That is, the amount of ultraviolet irradiation is preferably in the range of 1~50mJ / cm ^2, in particular in the range of 2~45mJ / cm ² is preferred.

Crosslinking by ultraviolet irradiation can be performed more efficiently when a photosensitizer is added to the release agent solution.
As specific examples of the photosensitizer, aromatic ketones such as benzophenone, P, P′-dimethoxybenzophenone, P, P′-dichlorobenzophenone P, P′-dimethylbenzophenone, acetophenone, and acetonaphthone give good results. In addition, aromatic aldehydes such as terephthalaldehyde, and quinone aromatic compounds such as methylanthraquinone can also be used.

  There is no restriction | limiting in particular as an adhesive applied to the peeling sheet of this invention, For example, selecting suitably from conventionally well-known adhesives, such as an acrylic adhesive, a polyester-type adhesive, a urethane type adhesive, for example, for example. Can do.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
In Examples and Comparative Examples, peel strength and adhesion to a substrate were measured and evaluated by the following methods.

(1) Peel strength
a) Normal peel force Release agent surface of release sheet to be tested and acrylic adhesive tape [base material: polyethylene terephthalate (PET) film with a thickness of 38 μm [trade name: Lumirror E20 # 50 white], adhesive agent : Acrylic adhesive [Product name: PL Thin, manufactured by Lintec Co., Ltd.] Adhesive coating amount (weight of solid content): 24 g / m < ² >] is put in contact and overlapped, and reciprocated once with a 2 kg roller. Each of the peel strengths was measured after standing for 1 day or 7 days under conditions of a temperature of 23 ° C. and a humidity of 50%. The measurement is performed using a universal tensile testing machine (Orientec Co., Ltd., model number: TENSILON UTM-4-100) at a temperature of 23 ° C and a humidity of 50%. This was done by peeling at a rate of minutes.
b) Peeling force after accelerated aging After leaving the release sheet to be tested for 1 day at a temperature of 23 ° C and a humidity of 50%, or for 1 day or 7 days at a temperature of 70 ° C, Acrylic adhesive tape [Base material: Polyethylene terephthalate (PET) film with a thickness of 38 μm [trade name: Lumirror E20 # 50 white], adhesive: Acrylic adhesive [Product made by Lintec, trade name: PL Shin ], Pressure-sensitive adhesive coating weight (weight of solid content: 24 g / m ² ) Each of the peel strengths was measured after standing for 1 day.
The measurement was performed by the same method as a) above.

(2) Adhesiveness with substrate The rub-off method, that is, the release agent layer surface of the release sheet to be tested is rubbed with a finger, the release agent layer is taken from the substrate, and the presence or absence of a desorption phenomenon is visually observed. Evaluation was made according to the following criteria.
○: Good without dropping from the base material △: Slightly dropped from the base material, but no problem in practical use ×: Poor because it falls off from the base material

(3) Measurement of silicone amount The silicone amount of the release agent layer of the release sheet to be tested was measured under the following conditions by X-ray photoelectron spectroscopy (XPS).
Measuring device: ESCA 5600 manufactured by PerkinElmer
X-ray source: Mg standard (15 KV, 400 W)
Extraction angle: 45 degrees Measurement time: 3 minutes Measurement elements: silicon (Si) and carbon (C)
The amount of Si was expressed as “%” by multiplying the value of Si / (Si + C) by 100.

Example 1
100 parts by weight of cis 1,4-polybutadiene (manufactured by JSR, trade name: JSRBR-10, containing 95% of cis 1,4 bond) and an antioxidant (trade name: Irganox HP2251 by Ciba Specialty Chemicals ) One part by weight was diluted with toluene to obtain a release agent solution having a solid content concentration of 1.0% by weight.
The release agent solution, a polyethylene terephthalate having a thickness of 38 [mu] m (PET) film (Mitsubishi Chemical Polyester Film Co., trade name: T100-38) on the surface of the coating at Meyer bar # 4 [coating amount (solid content Weight): 0.10 g / m @ 2] and then dried by heating at 100 DEG C. for 30 seconds.
Next, the coating layer was irradiated with ultraviolet rays under a condition of a conveyor speed of 40 m / min (ultraviolet ray irradiation amount: 22 mJ / cm @ 2) by a belt conveyor type ultraviolet ray irradiation device with a fusion H bulb 240 W / cm1 lamp, and cured. A sheet having a release agent layer was prepared.
The adhesion of the obtained release sheet to the substrate, the peel strength and the amount of the silicone compound were measured, and the results are shown in Table 1.

Example 2
A release sheet was prepared in the same manner as in Example 1 except that the amount of the antioxidant was 10 parts by weight with respect to 100 parts by weight of 1,4-polybutadiene.
The adhesion of the obtained release sheet to the substrate, the peel strength and the amount of the silicone compound were measured, and the results are shown in Table 1.

Example 3
A release sheet was prepared in the same manner as in Example 1 except that the antioxidant was changed to Sumilizer GS (trade name, manufactured by Sumitomo Chemical Co., Ltd.).
The adhesion of the obtained release sheet to the substrate, the peel strength and the amount of the silicone compound were measured, and the results are shown in Table 1.

Example 4
In the same manner as in Example 1 except that the antioxidant was changed to Sumilizer GS (trade name, manufactured by Sumitomo Chemical Co., Ltd.) and the blending amount was 10 parts by weight with respect to 100 parts by weight of 1,4-polybutadiene. A release sheet was prepared.
The adhesion of the obtained release sheet to the substrate, the peel strength and the amount of the silicone compound were measured, and the results are shown in Table 1.

Comparative Example 1
A release sheet was prepared in the same manner as in Example 1 except that the antioxidant was not blended.
The adhesion of the obtained release sheet to the substrate, the peel strength and the amount of the silicone compound were measured, and the results are shown in Table 1.

Comparative Example 2
A release sheet was prepared in the same manner as in Example 1 except that no antioxidant was added and no ultraviolet irradiation was performed.
The adhesion of the obtained release sheet to the substrate, the peel strength and the amount of the silicone compound were measured, and the results are shown in Table 1.

Comparative Example 3
A release sheet was prepared in the same manner as in Example 1 except that ultraviolet irradiation was not performed.
The adhesion of the obtained release sheet to the substrate, the peel strength and the amount of the silicone compound were measured, and the results are shown in Table 1.

Example 5
The UV irradiation after the coating and drying of the release agent solution is repeated twice with UV irradiation at a conveyor speed of 40 m / min by a belt conveyor type UV irradiation device with a fusion H bulb 240 W / cm 1 lamp (UV irradiation amount: 44 mJ / cm ² ), a release sheet was prepared in the same manner as in Example 1.
The adhesion of the obtained release sheet to the substrate, the peel strength and the amount of the silicone compound were measured, and the results are shown in Table 1.

Example 6
UV irradiation after the coating and drying of the release agent solution was performed under the condition of a conveyor speed of 40 m / min (ultraviolet irradiation amount: 11 mJ / cm ² ) using a belt conveyor type ultraviolet irradiation device with a fusion H bulb 120 W / cm 1 lamp. Except for this, a release sheet was prepared in the same manner as in Example 1.
The adhesion of the obtained release sheet to the substrate, the peel strength and the amount of the silicone compound were measured, and the results are shown in Table 1.

Example 7
The UV irradiation after the coating and drying of the release agent solution is performed under the condition of a conveyor speed of 40 m / min (ultraviolet irradiation amount: 5.5 mJ / cm ² ) using a belt conveyor type UV irradiation device with a fusion H bulb 60 W / cm 1 lamp. A release sheet was prepared in the same manner as in Example 1 except that this was done.
The adhesion of the obtained release sheet to the substrate, the peel strength and the amount of the silicone compound were measured, and the results are shown in Table 1.

Example 8
The UV irradiation after the coating and drying of the release agent solution is performed under the condition of a conveyor speed of 40 m / min (UV irradiation amount: 2.8 mJ / cm ² ) using a belt conveyor type UV irradiation device with one fusion H bulb 30 W / cm. A release sheet was prepared in the same manner as in Example 1 except that this was done.
The adhesion of the obtained release sheet to the substrate, the peel strength and the amount of the silicone compound were measured, and the results are shown in Table 1.

Example 9
By setting the solid content concentration of the release agent solution to 10.0% by weight, the coating amount (weight after drying) is set to 1.0 g / m ² , and the ultraviolet irradiation after the application and drying of the release agent solution is performed. Was carried out in the same manner as in Example 1 except that it was carried out at a conveyor speed of 40 m / min (ultraviolet irradiation amount: 11 mJ / cm ² ) using a belt conveyor type ultraviolet irradiation device with a fusion H bulb 120 W / cm 1 lamp. Created a sheet.
The adhesion of the obtained release sheet to the substrate, the peel strength and the amount of the silicone compound were measured, and the results are shown in Table 1.

Comparative Example 4
Cis 1,4-polybutadiene (JSRBR-10) 1,2- polybutadiene (JSR Corp., trade name: JSR BR- 810) was replaced with, the same procedure as in Example 1 to prepare a release sheet. The adhesion of the obtained release sheet to the substrate, the peel strength and the amount of the silicone compound were measured, and the results are shown in Table 1.

Comparative Example 5
100 parts by weight of a silicone release agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KS-847H) and 1 part by weight of a curing catalyst (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: CAT-PL-50T) are diluted with toluene, A release agent solution having a solid concentration of 1.1% by weight was obtained.
The release agent solution, a polyethylene terephthalate having a thickness of 38 [mu] m (PET) film (Mitsubishi Chemical Polyester Film Co., trade name: T100-38) on the surface of the coating at Meyer bar # 4 [coating amount (solid content Weight): 0.11 g / m @ 2] and then cured by heating at 130 DEG C. for 1 minute.
The adhesion of the obtained release sheet to the substrate, the peel strength and the amount of the silicone compound were measured, and the results are shown in Table 1.

  The release sheet of the present invention is a release sheet that does not adversely affect the electronic component when used in the field of mounting electronic components and has good peelability from the pressure-sensitive adhesive layer. It is possible to provide an adhesive laminate that is suitably used for applications related to precision electronic equipment such as assembly of a magnetic recording device (HDD).

Claims (5)

  A release sheet, wherein a release agent layer formed by applying a release agent solution containing 1,4-polybutadiene and an antioxidant on a substrate and curing by applying ultraviolet rays is provided. The release sheet according to claim 1, wherein the irradiation amount of ultraviolet rays is 1 to 50 mJ / cm ² .   The release sheet according to claim 1 or 2, wherein the content of the antioxidant is 0.1 to 15 parts by weight with respect to 100 parts by weight of 1,4-polybutadiene. The release sheet according to any one of claims 1 to 3, wherein a coating amount of the release agent liquid is 0.01 to 1.5 g / m ² as a weight of a solid content. The peeling according to any one of claims 1 to 4, wherein the base material is one selected from a paper base material, a laminated paper obtained by laminating a thermoplastic resin to a paper base material, a plastic film, and a laminated sheet including these. Sheet.