JP2005097470A - Regulating method of electrostatic charge caused by stripping of adhesive film and adherend - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive film which restrains the generation itself of static electricity at the time of stripping the adhesive film from an adherend such as various plastics and glass, and to provide its regulating method. <P>SOLUTION: The regulating method of the electrostatic charge generated by stripping of the adhesive film from the adherend is provided, wherein the adhesive film consists of a base material layer and an adhesive layer and uses as an adhesive (C) of the adhesive layer a mixture obtained by blending at least two kinds of adhesives, namely an adhesive (A) of the adhesive film that, when peeled, makes the adherend show positive electrostatic charge and an adhesive (B) of the adhesive film that makes the adrehend show negative electrostatic charge. In this method it is preferable that the adhesive (A) is an acrylic adhesive having a hydroxy group and a carboxy group as the functional groups and that the adhesive (B) is an acrylic adhesive having only a hydroxy group as the functional group. The method is particularly effective when the adherend is a polarizing plate or an LCD panel whose surface is mainly composed of triacetyl cellulose. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for adjusting charge generated when an adhesive film, an adhesive sheet, and an adhesive tape (hereinafter referred to as “adhesive film”) are peeled from an adherend.

Conventionally, when transporting various metal products, glass plates, plastic sheets, plastic plates, and electronic devices such as LCD panels, etc., to prevent the surface of these products from being damaged, contaminated and corroded, Adhesive film is widely applied to the surface. Such adhesive films are widely used for fixing silicon wafers and IC substrates and for the purpose of surface protection.

  As the base material of these adhesive films, plastic materials such as polyester, polyethylene, polypropylene, and polyvinyl chloride are used. An easily peelable pressure-sensitive adhesive layer such as acrylic, epoxy, urethane, polyethylene, and polyester is formed on the surface of these base materials.

  These adhesive films can be easily and integrally peeled off from the adherend after fulfilling the above-mentioned purpose. However, when the adhesive film is peeled off from the adherend, an adhesive is generated due to the generation of static electricity. In the film and the adherend, so-called peeling electrification that charges as charges having opposite polarities occurs. This peeling electrification not only causes the adherend to attract dust from the environment and becomes contaminated, but also causes various obstacles depending on the use of the adherend. For example, when the adherend is the electronic device component described above, the integrated circuit may be destroyed by a spark or the like caused by the peeling charging.

  For the purpose of solving such problems, a method of kneading carbon into the base material of the pressure-sensitive adhesive tape (for example, Patent Document 1) or a method of applying an ionic or nonionic antistatic agent to the surface of the base material (for example, Patent document 2) is known. Furthermore, a method of blending an alkali metal salt into the pressure-sensitive adhesive layer has also been proposed (Patent Document 3). In these methods, all of the static electricity of the pressure-sensitive adhesive film generated by peeling is transferred to the atmosphere through the substrate surface or the pressure-sensitive adhesive surface. It is intended to escape the heat and does not suppress the generation of static electricity due to peeling. Therefore, even if the static electricity charged on the adhesive film side can be released, there is no effect on the charging of the adherend, and it is difficult to avoid the above-mentioned obstacles.

On the other hand, by adding dimethyl sulfoxide and / or N-methylpyrrolidone to the pressure-sensitive adhesive layer, a pressure-sensitive adhesive tape is proposed that reduces the amount of static electricity generated when the pressure-sensitive adhesive tape is peeled off. (Patent Document 4). However, the present invention measures the peeling voltage when the pressure-sensitive adhesive tape itself is rewound by a winding device, and reduces the peeling charge between an arbitrary adherend and the pressure-sensitive adhesive film targeted by the present invention. That is not shown.
JP-A-63-99828 Japanese Utility Model Publication No. 63-131737 JP-A-6-128539 JP 2000-129221 A

  The present invention provides a method and an effective pressure-sensitive adhesive film that suppresses the generation of static electricity when the pressure-sensitive adhesive film is peeled off from an adherend such as various types of plastics and glass in order to reliably suppress the trouble caused by the peeling charge. The purpose is to do.

  That is, the present invention comprises a pressure-sensitive adhesive film (A) having a base layer and a pressure-sensitive adhesive layer, wherein the adherend exhibits a positive charge amount, and a pressure-sensitive adhesive film adhesive (B) having a negative charge amount. It is a method for adjusting the peel chargeability of an adhesive film and an adherend by mixing at least two kinds of adhesives to obtain an adhesive (C) for an adhesive layer. Furthermore, the adhesive (A) and the adhesive ( An adhesive film is prepared by adjusting the blending ratio of B), and the absolute value of the charge amount of the adherend when the adhesive film attached according to JIS Z 0237 is peeled off from the adherend is 10 nC or less. There is a method for adjusting the peel chargeability between the pressure-sensitive adhesive film and the adherend, characterized in that the blending ratio of the pressure-sensitive adhesive (A) and the pressure-sensitive adhesive (B) is set. Further, the pressure-sensitive adhesive (A) is an acrylic pressure-sensitive adhesive having a hydroxyl group and a carboxyl group as functional groups, and the pressure-sensitive adhesive (B) is an acrylic pressure-sensitive adhesive having only a hydroxyl group as a functional group. This is a method for adjusting the peel chargeability of the body, and further a method for adjusting the peel chargeability of the adherend film and the pressure sensitive adhesive film whose surface is a polarizing plate or LCD panel whose main component is triacetylcellulose. On the other hand, this invention is an adhesive film which used the adhesive (C) adjusted with the said method for the adhesive layer.

  By the method of the present invention, it is possible to obtain a pressure-sensitive adhesive film that suppresses the occurrence of peeling electrification when it is applied to and peeled from various plastics or glass. In particular, it is effective for obtaining a surface protective film of an electronic device component that is easily damaged by static electricity such as an LCD panel.

  The present invention suppresses static electricity itself generated when the adhesive film is peeled off from the adherend as described above, and the most important point is that the adherend exhibits a positive charge amount. (A) and the adhesive (B) of the adhesive film which shows negative charge amount are mixed, and it exists in the place used as the adhesive (C) of an adhesive layer.

  In the present invention, an adherend is first selected. Examples of the adherend include various plastic sheets, plastic plates, glass plates, and the like. Further, it may be an electronic device part such as an LCD panel made of these materials. Each of these has a unique charge train.

  On the other hand, the pressure-sensitive adhesive film used in the present invention is basically composed of a base material layer and a pressure-sensitive adhesive layer. A layer such as an antistatic layer may be provided between the pressure-sensitive adhesive layers. The base film is not particularly limited, and may be selected from films suitable for the purpose such as handling property, thickness accuracy, transparency, etc. General film such as polyester resin film and polyolefin resin film may be used. Used.

  The pressure-sensitive adhesive used in the pressure-sensitive adhesive layer in the present invention is not particularly limited as long as it satisfies the requirements such as easy peelability, and is generally such as acrylic, epoxy, urethane, polyethylene, and polyester. Among them, an acrylic pressure-sensitive adhesive is preferable because a pressure-sensitive adhesive having a wide range of peeling charge characteristics can be obtained. In addition, these pressure-sensitive adhesives may contain a cross-linking agent, a tackifier such as a terpene resin, a rosin resin, a plasticizer, an antiaging agent, a colorant, and the like as necessary. Any crosslinking agent may be used as long as it can exhibit a desired crosslinking effect depending on the resin used, and examples thereof include epoxy-based, urea resin, melamine-based, isocyanate-based, and phenol-based crosslinking agents.

  When the adhesive film is attached to and peeled off from the adherend, the present inventors have found that the charge train of the adhesive layer used in the adhesive film is greatly different from the charge train of the adherend. It has been found that peeling electrification occurs. When an adhesive film having a pressure-sensitive adhesive layer made of a specific pressure-sensitive adhesive is peeled from the adherend, the adherend exhibits a positive charge amount (adhesive (A)) and a negative charge amount. There is something (adhesive (B)). When the pressure-sensitive adhesive (C) obtained by mixing the pressure-sensitive adhesive (A) and the pressure-sensitive adhesive (B) is used as the pressure-sensitive adhesive layer, the absolute value of the charge amount of the adherend when it is applied to the adherend and peeled off is obtained. It can be suppressed to a very small value.

  The blending ratio of the pressure-sensitive adhesive (C) to the pressure-sensitive adhesive (A) and the pressure-sensitive adhesive (B) is to prepare a pressure-sensitive adhesive film using several pressure-sensitive adhesives having different ratios, and to JIS Z 0237. The blending ratio of the pressure-sensitive adhesive (C) is determined by setting the blending ratio in which the absolute value of the measured value is 10 nC or less for the charge amount of the adherend when the pressure-sensitive adhesive film is peeled off from the adherend. Can be set. If the absolute value of the peel charge amount exceeds 10 nC, the effect of suppressing the above-mentioned trouble due to static electricity may be insufficient depending on the purpose of use.

  As the pressure-sensitive adhesive used in the present invention, for example, as an acrylic pressure-sensitive adhesive, an acrylic polymer mainly composed of an alkyl acrylate ester and copolymerized with a polar monomer component is used. The acrylic acid alkyl ester is an alkyl ester of acrylic acid or methacrylic acid and is not particularly limited. For example, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, (meth) acrylic Examples include acid pentyl, isononyl (meth) acrylate, decyl (meth) acrylate, and lauryl (meth) acrylate. Examples of the polar monomer component to be copolymerized include monomers having a carboxyl group or a hydroxyl group, such as acrylic acid, maleic anhydride, and 2-hydroxyethyl (meth) acrylate. It becomes a functional group of the polymer. Depending on the type and / or copolymerization ratio, the sign (positive or negative) and the absolute value of the charge amount charged on the adherend when it is applied to the adherend and peeled off are greatly affected.

  Since this sign and absolute value vary depending on what the adherend is, specifically, it is necessary to set it experimentally for each case. For example, the surface of the adherend mainly contains triacetyl cellulose. In the case of a polarizing plate or an LCD panel as a component, if the polar monomer component of the acrylic resin of the pressure-sensitive adhesive uses only a hydroxyl group, the adherend is easily charged to the negative electrode and has both a hydroxyl group and a carboxyl group. If a material is used, the adherend is easily charged on the positive electrode. Using this knowledge as a guide, by selecting the pressure-sensitive adhesive (A) from the pressure-sensitive adhesive having only hydroxyl groups, on the other hand, selecting the pressure-sensitive adhesive (B) having both hydroxyl groups and carboxyl groups, and mixing both And set the adhesive (C). However, when the pressure-sensitive adhesives (A) and (B) are selected, it is necessary to select those that mix well with each other. Furthermore, when a curable pressure sensitive adhesive using a curing agent or the like is used, the charge amount of the adherend may not necessarily be reduced if a material having a greatly different curing reaction rate is mixed, and therefore the curing reaction rate is relatively close. It is preferable to select the pressure-sensitive adhesives (A) and (B) from those. Further, the pressure-sensitive adhesive constituting the pressure-sensitive adhesive (C) is not limited to the above-mentioned two types, and based on the same principle as long as the sign and absolute value of the peeling charge are clear. You may mix and use 3 or more types of adhesives.

  The pressure-sensitive adhesive film of the present invention is prepared by providing a pressure-sensitive adhesive layer on the surface of a base material layer film by a general method using the pressure-sensitive adhesive (C) set by the above method for a specific adherend. can get. For example, it can manufacture by apply | coating the composition which has an adhesive (C) as a main component on a base material layer film, forming an adhesive layer, and drying. The thickness of the base material layer and the pressure-sensitive adhesive layer may be appropriately selected depending on the purpose of use, and is not particularly limited. However, as the surface protective film, the base material layer is generally 10 to 200 μm, and the pressure-sensitive adhesive layer is The thing of the range of 5-50 micrometers is used.

Hereinafter, the present invention will be described more specifically with reference to examples. In the following Examples and Comparative Examples, the units representing the composition of the adhesive and the like are shown on a mass basis unless otherwise specified.
(Peeling charge measurement method)
Using a commercially available polarizing plate (30 mm × 100 mm) having a surface layer mainly composed of triacetyl cellulose as the adherend, the amount of charge to be peeled when the adhesive film is attached to and peeled from the adherend is as follows: Measured according to the conditions of
1. Measurement-related equipment Charge measurement: Nano-Coulomb meter and Faraday cage by Electro-Tech System Ionizer: SIMCO AEROSTAT PC
2. Preparation and method for measurement Using the adhesive film (excluding the peelable film) prepared in each Reference Example and Example, the adherend and the adhesive film were each removed by using the above ionizer, and then stuck together. The charge was removed again. Adhering to the adherend was performed by a method based on JIS Z 0237, and the adhering area was 25 mm × 90 mm. Grasp the edge of the adherend (the part where the adhesive film is not attached) and the adhesive film with separate ceramic tweezers, peel the adhesive film at a speed of 3,000 mm / min. The body was put into a Faraday cage and the charge amount was read. The obtained results are summarized in Table 1.

(Reference Example 1)
To 100 parts of an acrylic adhesive (manufactured by Soken Chemical Co., Ltd., SK Dyne 1495), 2.0 parts of a curing agent (manufactured by Soken Chemical Co., Ltd., curing agent L-45) was added to prepare an adhesive coating solution. The coating solution was applied to the antistatic surface of an antistatic polyester film having a thickness of 38 μm (manufactured by Mitsubishi Chemical Polyester Film Co., Ltd., T100G) using a bar coater and dried at 100 ° C. for 1 minute. The thickness of the adhesive layer after drying was about 18 μm. Further, a peelable film (MRF-25, manufactured by Mitsubishi Chemical Polyester Film Co., Ltd.) having a thickness of 25 μm was bonded to the adhesive layer side. Using this pressure-sensitive adhesive film, the peel charge amount of the adherend was measured by the above evaluation method and found to be 17.3 nC. Therefore, this pressure-sensitive adhesive was designated as pressure-sensitive adhesive (A), and in the examples described later. Using.
(Reference Example 2)
A pressure-sensitive adhesive film was prepared in the same manner as in Reference Example 1 except that an acrylic pressure-sensitive adhesive (manufactured by Soken Chemical Co., Ltd., SK Dyne 1499) was used, and the peel charge amount of the adherend was measured in the same manner. Since it was 18.8 nC, this adhesive was used as an adhesive (B) and used in the examples described later.
SK Dyne 1495
Functional group: OH / COOH, Tg: about −70 ° C., molecular weight: about 1,200,000 SK Dyne 1499
Functional group: OH, Tg: about −60 ° C., molecular weight: about 800,000

(Examples 1-3)
A pressure-sensitive adhesive (C) prepared by mixing the pressure-sensitive adhesive (A) selected in Reference Example 1 and the pressure-sensitive adhesive (B) selected in Reference Example 2 as an acrylic pressure-sensitive adhesive in the ratio shown in Table 1 An adhesive film was prepared in the same manner as in the Reference Example except that the peel charge amount of the adherend was measured in the same manner. The results are shown in Table 1.

  From the results in Table 1, the absolute value of the peel charge amount when the adhesive films of Examples 1 to 3 were applied to the adherend and peeled off was 10 nC or less, which was very good, and the generation of static electricity at the time of peeling itself The effect which suppresses was confirmed.

  By using the method of the present invention, it is possible to obtain a pressure-sensitive adhesive film having a very small peel charge amount at the time of peeling when used by being stuck to various plastic plates or glass plates. Therefore, the present invention can be applied to the design of a pressure-sensitive adhesive composition used for a surface protective film used by attaching to an electronic device component sensitive to static electricity such as an LCD panel or a cover film for a carrier tape.

Claims (5)

  At least a pressure-sensitive adhesive (A) of a pressure-sensitive adhesive film having a positive charge amount when peeled and comprising a base material layer and a pressure-sensitive adhesive layer, and a pressure-sensitive adhesive (B) of a pressure-sensitive adhesive film exhibiting a negative charge amount A method for adjusting the peel chargeability of an adhesive film and an adherend by mixing two types of adhesives to obtain an adhesive (C) for an adhesive layer.   An adhesive film is prepared by adjusting the blending ratio of the adhesive (A) and the adhesive (B), and the adherent film adhered according to JIS Z 0237 is peeled off from the adherend. 2. The adhesive film and adherend peeling charge according to claim 1, wherein the mixing ratio of the adhesive (A) and the adhesive (B) is set so that the absolute value of the charge amount is 10 nC or less. How to adjust sex.   The pressure-sensitive adhesive (A) is an acrylic pressure-sensitive adhesive having a hydroxyl group and a carboxyl group as functional groups, and the pressure-sensitive adhesive (B) is an acrylic pressure-sensitive adhesive having only a hydroxyl group as a functional group. The adjustment method of the peeling electrification property of the adhesive film and adherend as described in 1.   The method for adjusting the peeling chargeability of the pressure-sensitive adhesive film and the adherend according to any one of claims 1 to 3, wherein the adherend is a polarizing plate or an LCD panel whose surface is mainly composed of triacetylcellulose.   The adhesive film which used the adhesive (C) adjusted with the method of any one of Claims 1-4 for the adhesive layer.