ADHESIVE TAPE, METHOD FOR FIXING ELECTRONIC DEVICE COMPONENT OR ON-BOARD DEVICE COMPONENT, AND METHOD FOR PRODUCING ELECTRONIC DEVICE OR ON-BOARD DEVICE

Abstract

The present invention aims to provide an adhesive tape that is easily peelable while capable of maintaining high adhesion at high temperature. The present invention also aims to provide a method for fixing an electronic device component or an in-vehicle device component using the adhesive tape and a method for producing an electronic device or an in-vehicle device. Provided is an adhesive tape including an adhesive layer containing: an acrylic copolymer; and 0.01 parts by weight or more and 10 parts by weight or less of a compound having a structure represented by the following formula (A) or (B) relative to 100 parts by weight of the acrylic copolymer:

##STR00001##

Claims

1. An adhesive tape comprising an adhesive layer containing: an acrylic copolymer; and 0.01 parts by weight or more and 10 parts by weight or less of a compound having a structure represented by the following formula (A) or (B) relative to 100 parts by weight of the acrylic copolymer: ##STR00004##

2. The adhesive tape according to claim 1, wherein the acrylic copolymer contains more than 50% by weight of a structural unit derived from an alkyl (meth)acrylate.

3. The adhesive tape according to claim 1, wherein the acrylic copolymer contains a structural unit derived from n-heptyl (meth)acrylate.

4. The adhesive tape according to claim 3, wherein the acrylic copolymer contains 30% by weight or more of the structural unit derived from n-heptyl (meth)acrylate.

5. The adhesive tape according to claim 4, wherein the acrylic copolymer contains more than 50% by weight of the structural unit derived from n-heptyl (meth)acrylate.

6. The adhesive tape according to claim 1, wherein in the acrylic copolymer, an amount of a structural unit derived from a (meth)acrylate containing an alkyl group having a carbon number of 8 or greater is 50% by weight or less.

7. The adhesive tape according to claim 1, wherein the acrylic copolymer further contains a structural unit derived from a monomer containing a crosslinkable functional group.

8. The adhesive tape according to claim 7, wherein the acrylic copolymer contains 0.01% by weight or more and 20% by weight or less of the structural unit derived from a monomer containing a crosslinkable functional group.

9. The adhesive tape according to claim 7, wherein the monomer containing a crosslinkable functional group comprises a monomer containing a hydroxy group, and the acrylic copolymer contains 0.01% by weight or more and 20% by weight or less of a structural unit derived from the monomer containing a hydroxy group.

10. The adhesive tape according to claim 1, wherein the acrylic copolymer has a weight average molecular weight of 200,000 or greater and 2,000,000 or less.

11. The adhesive tape according to claim 1, wherein the adhesive layer further contains a tackifier resin.

12. The adhesive tape according to claim 1, wherein the adhesive layer does not contain a surfactant.

13. The adhesive tape according to claim 1, wherein the adhesive layer has a gel fraction of 10% by weight or more and 70% by weight or less.

14. The adhesive tape according to claim 1, wherein the adhesive layer has a bio-derived carbon content of 10% by weight or more.

15. The adhesive tape according to claim 1, used for fixing an electronic device component or an in-vehicle device component.

16. A method for fixing an electronic device component or an in-vehicle device component, comprising fixing an electronic device component or an in-vehicle device component using the adhesive tape according to claim 1.

17. A method for producing an electronic device or an in-vehicle device, comprising the method for fixing an electronic device component or an in-vehicle device component according to claim 16.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0124] FIG. 1 is a schematic view illustrating a repulsion resistance test on an adhesive tape.

DESCRIPTION OF EMBODIMENTS

[0125] The embodiments of the present invention are more specifically described in the following with reference to examples. These examples are not intended to limit the present invention.

Example 1

(1) Production of Acrylic Copolymer

[0126] Ethyl acetate as a polymerization solvent was added into a reaction vessel and bubbled with nitrogen. Subsequently, with nitrogen flowing into the reaction vessel, the reaction vessel was heated to start reflux. A polymerization initiator solution obtained by diluting 0.1 parts by weight of azobisisobutyronitrile as a polymerization initiator 10-fold with ethyl acetate was added into the reaction vessel. Subsequently, 50 parts by weight of n-butyl acrylate (BA, produced by Mitsubishi Chemical Corporation), 44.9 parts by weight of 2-ethylhexyl acrylate (2-EHA, produced by Mitsubishi Chemical Corporation), 5 parts by weight of acrylic acid (AAc, produced by Nippon Shokubai Co., Ltd.), and 0.1 parts by weight of 2-hydroxyethyl acrylate (2-HEA, produced by Osaka Organic Chemical Industry Ltd.) were dripped over two hours. After dripping was complete, the polymerization initiator solution obtained by diluting 0.1 parts by weight of azobisisobutyronitrile as a polymerization initiator 10-fold with ethyl acetate was added into the reaction vessel again. Polymerization reaction was performed for four hours to give a solution containing an acrylic copolymer.

[0127] The obtained acrylic copolymer was diluted 50-fold with tetrahydrofuran (THF). The obtained dilution was filtered through a filter (material: polytetrafluoroethylene, pore size: 0.2 μm) to prepare a measurement sample. This measurement sample was fed to a gel permeation chromatograph (produced by Waters Corporation, 2690 Separations Model) and subjected to GPC measurement at a sample flow rate of 1 mL/min and a column temperature of 40° C. to measure the polystyrene equivalent molecular weight of the acrylic copolymer. Thus, the weight average molecular weight was determined.

(2) Production of Compound Having Structure Represented by Formula (A) or (B)

[0128] n-Heptyl acrylate, n-heptyl alcohol, and sulfuric acid were mixed at a ratio by mole of 2:1:0.2 and reacted at 110° C. (addition reaction). The reaction product was distilled to give a compound having a structure represented by the formula (A) or (B).

(3) Production of Adhesive Tape

[0129] An isocyanate crosslinking agent (produced by Tosoh Corporation, CoronateL-45) was added to the obtained solution containing the acrylic copolymer such that the amount of the solids of the crosslinking agent was 0.5 parts by weight relative to 100 parts by weight of the acrylic copolymer. Further, 0.5 parts by weight of the obtained compound having a structure represented by the formula (A) or (B) was added, whereby an adhesive solution was prepared. The adhesive solution was applied to the release-treated surface of a release-treated PET film having a thickness of 75 μm such that the adhesive layer after drying would have a thickness of 50 μm, and then dried at 110° C. for five minutes. This adhesive layer was placed on the release-treated surface of a release-treated PET film having a thickness of 75 μm and left to stand at 40° C. for 48 hours, whereby an adhesive tape (non-support type) was obtained.

(4) Measurement of Gel Fraction of Adhesive Layer

[0130] The release film on one surface of the obtained adhesive tape was removed. The adhesive tape was attached to a PET film having a thickness of 23 μm (produced by Futamura Chemical Co., Ltd., FE2002) and cut to a 20 mm×40 mm flat rectangular shape. The release film on the other surface of the adhesive tape was removed, whereby a specimen was prepared. The weight of the specimen was measured. The specimen was immersed in ethyl acetate at 23° C. for 24 hours, taken out of the ethyl acetate, and dried at 110° C. for 1 hour. The weight of the specimen after drying was measured, and the gel fraction was calculated by the following equation (1).

Gel fraction (% by weight)=100×(W.sub.2−W.sub.0)/(W.sub.1−W.sub.0)  (1)

(W.sub.0: the weight of the substrate (PET film), W.sub.1: the weight of the specimen before immersion, W.sub.2: the weight of the specimen after immersion and drying)

Examples 2 to 14 and Comparative Examples 1 to 4

[0131] An adhesive tape was obtained as in Example 1 except that the type and compounding amount of the acrylic monomers constituting the acrylic copolymer, the weight average molecular weight of the acrylic copolymer, the amount of the compound having a structure represented by the formula (A) or (B), and the compounding amount and type of the tackifier resins and the crosslinking agents were changed as shown in Table 1.

[0132] In Examples 3 to 14 and Comparative Examples 2 to 4, n-heptyl acrylate (C7) was used that was prepared by esterifying n-heptyl alcohol (produced by Tokyo Chemical Industry Co., Ltd.) with acrylic acid (AAc, produced by Nippon Shokubai Co., Ltd.).

[0133] In Examples 2, 4 to 7, and 9 and Comparative Examples 1 to 4, 10 parts by weight of a terpene phenolic resin A, 10 parts by weight of a polymerized rosin ester resin B, and 10 parts by weight of a hydrogenated rosin ester resin C were used as tackifier resins. The tackifier resins used were the following bio-derived tackifier resins.

[0134] Terpene phenolic resin A (produced by Yasuhara Chemical Co., Ltd., G150, softening point: 150° C., bio-derived carbon content 67% by weight)

[0135] Polymerized rosin ester resin B (hydroxy value: 46, softening point: 152° C., bio-derived carbon content 95% by weight)

[0136] Hydrogenated rosin ester resin C (produced by Arakawa Chemical Industries Ltd., KE359, hydroxy value: 40, softening point: 100° C., bio-derived carbon content 95% by weight)

Examples 15 and 16

[0137] An adhesive tape was obtained as in Example 3 except that the weight average molecular weight of the acrylic copolymer was changed as shown in Table 2.

<Evaluation>

[0138] The adhesive tapes obtained in the examples and the comparative examples were evaluated by the following methods. Tables 1 and 2 show the results.

(1) Easy Peelability (Peeling Force for SUS Plate)

[0139] The 180° peeling force of each adhesive tape for a SUS plate was measured in conformity with JIS Z 0237:2009.

[0140] Specifically, first, one surface (the side not to be measured) of the adhesive tape was backed with a polyethylene terephthalate film having a thickness of 23 μm (produced by Futamura Chemical Co., Ltd., FE2002). The adhesive tape was then cut to a size of 25 mm wide×75 mm long to prepare a specimen. This specimen was placed on a SUS plate (SUS304-2B) with the adhesive layer (the side to be measured) facing the SUS plate. A 2-kg rubber roller was then moved back and forth once on the specimen at a speed of 300 mm/min to bond the specimen to the SUS plate. The specimen was then left to stand for 20 minutes at 23° C. and a humidity of 50%. Thus, a test sample was produced. The adhesive tape and the SUS plate of the test sample were peeled apart in the 180° direction at a tensile speed of 300 mm/min under the conditions of 23° C. and a humidity of 50% in conformity with JIS Z 0237:2009, and the peeling force (N/25 mm) was measured.

[0141] The easy peelability was evaluated as “∘” (Good) when the peeling force for the SUS plate was 4 N/25 mm or greater and 20 N/25 mm or less. The easy peelability was evaluated as “×” (Poor) when the peeling force was less than 4 N/25 mm or greater than 20 N/25 mm.

(2) Adhesion at High Temperature (Repulsion Resistance Test)

[0142] FIG. 1 is a schematic view illustrating a repulsion resistance test of an adhesive tape.

[0143] As shown in FIG. 1, an adhesive tape 9 was cut to a flat rectangular shape (25 mm wide×150 mm long). The adhesive tape 9 was used to bond an aluminum plate 10 (25 mm wide×150 mm long×0.3 mm thick) and a polycarbonate resin plate 11 (25 mm wide×200 mm long×1 mm thick). The position of the adhesive tape 9 was adjusted to the central part of the polycarbonate resin plate 11 in the longitudinal direction. A 2-kg rubber roller was moved back and forth once on the polycarbonate resin plate 11 at a speed of 300 mm/min to integrate the polycarbonate resin plate 11 and the aluminum plate 10 via the adhesive tape 9. The workpiece was left to stand at 23° C. for 24 hours, whereby a test sample 12 was produced. The test sample 12 was set on a fixture 13 as shown in FIG. 1. Bending stress was applied in the vertical direction of the test sample 12 to deform the test sample 12 into an arc-like curved state such that the distance between the ends of the polycarbonate resin plate 11 in the longitudinal direction was 180 mm. The test sample 12 in this state was placed in an oven at 85° C. and left to stand for 24 hours. The test sample 12 in the arc-like curved state was taken out of the oven, and a height H (mm) of partial detachment between the aluminum plate 10 and the polycarbonate resin plate 11 was measured with a caliper.

[0144] The adhesion at high temperature was evaluated as “∘” (Good) when the height H of the partial detachment in the repulsion resistance test was 8 mm or less. The adhesion at high temperature was evaluated as “×” (Poor) when the height H of the partial detachment was greater than 8 mm.

(3) Shear Holding Power at High Temperature

[0145] The holding power of the adhesive tapes according to Examples 3, 15, and 16 was measured. Table 2 shows the results. The shear holding power of each adhesive tape at high temperature was measured in conformity with JIS Z 0237:2009.

[0146] Specifically, first, one surface (the side not to be measured) of the adhesive tape was backed with a polyethylene terephthalate film (produced by Futamura Chemical Co., Ltd., FE2002) having a thickness of 23 μm. The adhesive tape was then cut to a size of 25 mm wide×75 mm long to prepare a specimen. This specimen was placed on a SUS304-2B plate (2 mm thick, 50 mm wide, and 80 mm long) with the adhesive layer (the side to be measured) facing the SUS304-2B plate. Then, a 2-kg rubber roller was moved back and forth once on the specimen at a speed of 300 mm/min to bond the specimen to the SUS304-2B plate. The specimen was then left to stand for 20 minutes at 23° C. and a humidity of 50%. Thus, a test sample was produced. This test sample was placed in an environment at 80° C. and a humidity of 50% and left to stand for 15 minutes. A 1-kg weight was then attached to the polyethylene terephthalate film of the test sample such that a load in a shear direction was applied in conformity with JIS Z 0237:2009. One hour after the weight was attached, the amount of slippage of the adhesive layer in the shear direction from the position where it was bonded to the SUS304-2B plate was measured.

[0147] The shear holding power at high temperature was evaluated as “∘” (Good) when the amount of slippage was less than 0.5 mm. The shear holding power at high temperature was evaluated as “Δ” (Fair) when the amount of slippage was 0.5 mm or greater.

TABLE-US-00001 TABLE 1 Example 1 2 3 4 5 6 7 8 9 10 Adhesive Acrylic n-Butyl acrylate (BA) 50 50 — — — — — 64.9 64.9 44.9 layer copolymer 2-Ethylhexyl acrylate 44.9 44.9 — — — — — — — — [parts by (2-EHA) weight] n-Heptyl acrylate (C7) — — 94.9 94.9 94.9 94.9 94.7 30 30 50 Isobornyl acrylate (IBOA) — — — — — — — — — — Acrylic acid (AAc) 5 5 5 5 5 5 5 5 5 5 2-Hydroxy ethyl acrylate 0.1 0.1 0.1 0.1 0.1 0.1 0.3 0.1 0.1 0.1 (2-HEA) Compound having structure 0.5 0.5 0.5 0.01 0.5 10 0.5 0.5 0.5 0.5 represented by formula (A) or (B) [parts by weight] Tackifier resin (TF) [parts by weight] 30 — 30 30 30 30 — 30 — Crosslinking agent [parts by weight] 0.5 1.5 0.5 1.5 1.5 1.5 1.5 0.5 1.5 0.5 Weight average molecular weight of 100 100 116 116 116 116 62 119 119 120 acrylic copolymer (Mw) [× 10.sup.4] Gel fraction of adhesive layer [% by weight] 34 38 35 37 37 35 33 38 39 35 Evaluation Easy Peeling force for SUS 10.5 18.5 10.2 18.0 15.6 6.4 15.2 11.7 19.0 12.1 peelability plate (N/25 mm) Rating ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ Adhesion at Height of partial 4 3 2 0 0 7 5 3 5 3 high detatchment (mm) temperature Rating ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ (repulsion resistance test) Comparative Example 11 12 13 14 1 2 3 4 Adhesive Acrylic n-Butyl acrylate (BA) — — — — 50 — — — layer copolymer 2-Ethylhexyl acrylate — — — — 44.9 — — — [parts by (2-EHA) weight] n-Heptyl acrylate (C7) 64 85 75 58.9 — 94.9 94.9 94 Isobornyl acrylate (IBOA) 30 — — 40 — — — — Acrylic acid (AAc) 1 5 5 1 5 5 5 5 2-Hydroxy ethyl acrylate 5 10 20 0.1 0.1 0.1 0.1 1 (2-HEA) Compound having structure 0.5 0.5 0.5 0.5 — — 15 — represented by formula (A) or (B) [parts by weight] Tackifier resin (TF) [parts by weight] — — — — 30 30 30 30 Crosslinking agent [parts by weight] 0.5 0.5 0.5 0.5 1.5 1.5 1.5 1.5 Weight average molecular weight of 102 104 106 108 100 116 116 115 acrylic copolymer (Mw) [× 10.sup.4] Gel fraction of adhesive layer [% by weight] 45 51 67 31 38 37 34 75 Evaluation Easy Peeling force for SUS 13.8 9.5 8.3 15.3 21.3 20.3 3.8 8.5 peelability plate (N/25 mm) Rating ◯ ◯ ◯ ◯ X X X ◯ Adhesion at Height of partial 4 4 7 2 3 0 10 15 high temperature detatchment (mm) (repulsion Rating ◯ ◯ ◯ ◯ ◯ ◯ X X resistance test)

TABLE-US-00002 TABLE 2 Example 3 15 16 Adhesive Acrylic copolymer n-Butyl acrylate (BA) — — — layer [parts by weight] 2-Ethylhexyl — — — acrylate (2-EHA) n-Heptyl acrylate (C7) 94.9 94.9 94.9 Isobornyl acrylate (IBOA) — — — Acrylic acid (AAc) 5 5 5 2-Hydroxy ethyl 0.1 0.1 0.1 acrylate (2-HEA) Compound having structure represented 0.5 0.5 0.5 by formula (A) or (B) [parts by weight] Tackifier resin (TF) [parts by weight] — — — Crosslinking agent [parts by weight] 0.5 0.5 0.5 Weight average molecular weight of acrylic copolymer (Mw) [×10.sup.4] 116 40 50 Gel fraction of adhesive layer [% by weight] 35 22 27 Evaluation Easy peelability Peeling force for 10.2 12.2 11.8 SUS plate (N/25 mm) Rating ◯ ◯ ◯ Adhesion at high Height of partial 2 7 5 temperature (repulsion detatchment (mm) resistance test) Rating ◯ ◯ ◯ Shear holding power Amount of slippage [mm] 0.1 0.6 0.3 at high temperature Rating ◯ Δ ◯

INDUSTRIAL APPLICABILITY

[0148] The present invention can provide an adhesive tape that is easily peelable while capable of maintaining high adhesion at high temperature. The present invention can also provide a method for fixing an electronic device component or an in-vehicle device component using the adhesive tape and a method for producing an electronic device or an in-vehicle device.

REFERENCE SIGNS LIST

[0149] 9 adhesive tape [0150] 10 aluminum plate [0151] 11 polycarbonate resin plate [0152] 12 test sample [0153] 13 fixture