JPH10158619A - Self-adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a self-adhesive compsn. which, when applied to a foamed substrate, gives a self-adhesive tape or sheet excellent in adhesion not only to a flat plane but also to a curved adhered by compounding an acrylic copolymer with a xylene resin, a chlorine compd., a tackifier, and a cross-linker. SOLUTION: This compsn. comprises an acrylic copolymer (A), a xylene resin (B), a chlorine compd. (C), a tackifier (D), and a cross-linker (E). Ingredient A is prepf. a copolymer of 60-99.9wt.% alkyl (meth)acrylate, 0.01-40wt.% functional monomer such as acrylic acid, and 0-39.9wt.% other monomers and pref. has a wt. average mol.wt. of 400,000 or higher. Ingredient B is one contg. 5wt.% or higher methylol groups and is used pref. in an amt. of 2-10wt.%. Ingredient B is pref. chlorinated polypropylene and is used in an amt. of 0.3-3wt.%. Ingredient D is compounded pref. in an amt. of 5-30wt.%. Pref. 1-3wt.% polyisocyanate is used as the ingredient E.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-sensitive adhesive composition used for a pressure-sensitive adhesive tape or a pressure-sensitive adhesive sheet, and more particularly to a pressure-sensitive adhesive composition useful for processed foam products.

[0002]

2. Description of the Related Art Conventionally, acrylic resins have been frequently used as adhesives in various adhesive processed products such as adhesive tapes and sheets, and recently, resins such as polypropylene (PP), polyethylene (PE), and urethane have been used. Pressure-sensitive adhesive tapes and sheets obtained by transferring and applying a pressure-sensitive adhesive to such a base material using a foam as a base material are used for automotive applications and the like.

[0003]

However, when the above-described base material is used, unlike the base material such as paper, it is difficult to sufficiently secure the adhesive strength (adhesive strength) between the base material and the adhesive. In addition, when the pressure-sensitive adhesive tape (sheet) using such a base material is adhered to a curved surface, the base material has a strong stiffness, and therefore has poor followability (adhesion) to a curved adherend surface. It is needed.

[0004]

[Means to solve the problem] Therefore, the present inventors,
In view of such circumstances, as a result of intensive studies, an adhesive comprising an acrylic copolymer (A), a xylene resin (B), a chlorinated compound (C), a tackifier (D) and a crosslinking agent (E) The composition has excellent adhesiveness not only to flat surfaces but also to curved surfaces.
The inventors have found that they have excellent adhesiveness and the like, and have completed the present invention. Further, the pressure-sensitive adhesive composition of the present invention is of course useful for pressure-sensitive adhesive tapes (sheets) based on kraft paper, PET, polystyrene, vinyl chloride, and the like. In particular, polyurethane foams, polystyrene foams, Foam such as ABS foam, rubber foam (chloroprene rubber, EPDM, etc.) foam, vinyl chloride foam, polyethylene foam, polypropylene foam, phenol foam, urea foam, etc. It is very useful for used adhesive tapes (sheets).

[0005]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below.
The pressure-sensitive adhesive composition of the present invention comprises an acrylic copolymer (A),
The acrylic copolymer (A) is composed of a xylene resin (B), a chlorinated compound (C), a tackifier (D), and a cross-linking agent (E). It is preferable that the above-mentioned alkyl (meth) acrylate (A1), functional group-containing monomer (A2) and other monomer (A3) are used. As the alkyl acrylate (A1) having 11 or more carbon atoms, acrylic acid 2- Ethylhexyl, lauryl acrylate, benzyl acrylate,
Examples thereof include cyclohexyl acrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, benzyl methacrylate, and cyclohexyl methacrylate. Among them, 2-ethylhexyl acrylate is preferably used.

The functional group-containing monomer (A2) includes a carboxyl group, a hydroxyl group, a glycidyl group,
Monomers containing any functional group of acetoacetyl group, specifically, acrylic acid, methacrylic acid, monocarboxylic acids such as crotonic acid, maleic acid,
Polycarboxylic acids such as fumaric acid, citraconic acid, glutaconic acid and itaconic acid and carboxyl group-containing monomers such as anhydrides thereof, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-chloro Hydroxyl-containing monomers such as -2-hydroxypropyl (meth) acrylate, diethylene glycol mono (meth) acrylate and N-methylol acrylamide; glycidyl group-containing monomers such as glycidyl methacrylate and allyl glycidyl ether;
And acetoacetyl group-containing monomers obtained by reacting a functional group-containing ethylenically unsaturated monomer such as -hydroxyethyl (meth) acrylate with diketene, and use of a carboxyl group-containing monomer is particularly preferable.

Further, other monomers (A3) include:
Ethyl acrylate, n-butyl acrylate, acrylic acid
iso-butyl, methyl acrylate, methyl methacrylate,
Examples thereof include alkyl (meth) acrylates having 1 to 10 carbon atoms such as ethyl methacrylate and propyl methacrylate, vinyl acetate, acrylonitrile, methacrylonitrile, and styrene.

The amount (copolymerization ratio) of (A1) to (A3) is not particularly limited, but (A1) is 60 to 99.9% by weight, (A2) is 0.01 to 40% by weight, A3) from 0 to 3
When the content of (A1) is less than 60% by weight, the adhesive strength is reduced, and when the content is more than 99.9% by weight, crosslinking is insufficient, which is not preferable. If (A2) is less than 0.01% by weight, the crosslinking reaction does not proceed,
If the amount is more than 3% by weight, the crosslinking reaction is excessive, which is not preferable. If the amount of (A3) is more than 39.9% by weight, the adhesive strength is undesirably reduced.

[0009] The acrylic copolymer (A) is (A)
It can be easily produced by a method well known to those skilled in the art, such as radical copolymerization of 1) to (A3) in an organic solvent. Examples of the organic solvent used for such polymerization include aromatic hydrocarbons such as toluene and xylene, esters such as ethyl acetate and butyl acetate, aliphatic alcohols such as n-propyl alcohol and iso-propyl alcohol, methyl ethyl ketone, methyl Ketones such as isobutyl ketone and cyclohexanone, and the like.Examples of the polymerization catalyst used include azobisisobutyronitrile, benzoyl peroxide, di-t-butyl peroxide, and cumene hydroperoxide, which are ordinary radical polymerization catalysts. And the like are specific examples. Thus, the acrylic copolymer (A) is obtained, and the weight average molecular weight of such a polymer is preferably 400,000 or more,
Further, it is preferably 500,000 to 800,000, and the weight average molecular weight is 40
If it is less than 10,000, heat resistance is insufficient, which is not preferable.

The xylene resin (B) used in the present invention has a methylol group content of 5.0% by weight or less (more preferably 1.5 to 5% by weight).
(3.5% by weight) is preferable. If the content exceeds 5.0% by weight, the pot life becomes short, which is not preferable. Examples of a method containing such a methylol group include a method of performing an addition reaction between xylene and formaldehyde. The content of the xylene resin (B) in the pressure-sensitive adhesive composition is preferably from 0.5 to 50% by weight, more preferably from 2 to 10% by weight. When the content is less than 0.5% by weight, the adhesive strength is reduced. And conversely 50% by weight
Exceeding the heat resistance and holding power are not preferred.

The chlorinated compound (C) used in the present invention includes chlorinated polypropylene and chlorinated polyethylene, and chlorinated polypropylene is particularly preferably used. The content of the chlorinated compound (C) in the pressure-sensitive adhesive composition is preferably 0.5 to 20% by weight, more preferably 0.5 to 20% by weight.
3.0% by weight is preferable, and the content is 0.5% by weight.
When the amount is less than 20%, the adhesive strength decreases. On the contrary, when the amount exceeds 20% by weight, the holding force decreases, which is not preferable.

The tackifier (D) used in the present invention includes a temper resin, a phenol resin, a silicone resin,
Coumarone-based resins, rosin-based compounds (rosin or water-added rosin esters), petroleum resins, and the like are preferable, and rosin-based compounds (rosin or water-added rosin esters) are preferably used.

Tackifier (D) in the pressure-sensitive adhesive composition
Is preferably 1 to 50% by weight, more preferably 5 to 30% by weight.
If the content is less than 1% by weight, the adhesive strength will not increase, while if it exceeds 50% by weight, the adhesive strength will be insufficient, which is not preferable.

The crosslinking agent (E) used in the present invention includes epoxy compounds, metal salts, metal alkoxides, aldehyde compounds, non-amino resin amino compounds, urea compounds, isocyanate compounds, metal chelate compounds, melamine compounds, Crosslinking agents used for ordinary pressure-sensitive adhesives, such as aziridine-based compounds, can be mentioned. Of these, particularly preferred are isocyanate-based compounds, and more preferred are polyfunctional isocyanates, for example, trimethylolpropane adduct of tolylene diisocyanate, ethylene diisocyanate Examples thereof include 1,4-butane diisocyanate, dicyclohexylmethane diisocyanate, cyclohexane diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and isophorone diisocyanate.

The content of the crosslinking agent (E) in the pressure-sensitive adhesive composition is preferably from 0.1 to 5% by weight, more preferably from 1 to 3% by weight, and if the content is less than 0.1% by weight. The crosslinking reactivity is poor, and if it exceeds 5% by weight, the crosslinking reaction becomes excessive, which is not preferable. An acid catalyst, for example, a crosslinking accelerator such as paratoluenesulfonic acid, phosphoric acid, hydrochloric acid, or ammonium chloride can be used in combination to promote the crosslinking. 10 to 50% by weight with respect to the weight. Thus, the pressure-sensitive adhesive composition of the present invention is obtained.However, a conventionally known pressure-sensitive adhesive additive may be added to the pressure-sensitive adhesive composition as needed without departing from the purpose of the present invention. Examples of such known additives include pigments, plasticizers, stabilizers, and fillers.

In using the pressure-sensitive adhesive composition of the present invention, the pressure-sensitive adhesive composition of the present invention is used as a resin solid content of 40 to 5%.
A solution of about 0% by weight (solvent: ethyl acetate, toluene, xylene, acetone, ethanol, methanol, isopropyl alcohol, etc.) is applied on a release paper with an applicator, dried at 80 ° C. for 1 minute, and then subjected to a substrate. By performing transfer coating on the substrate, an adhesive layer can be formed on the substrate. Generally, the film thickness after drying is 50 to 75.
Adjust so as to be about μm.

Such a substrate is not particularly limited, and is of course useful for an adhesive tape (sheet) based on kraft paper, PET, polystyrene, vinyl chloride, or the like. Foam, A
BS foam, rubber (chloroprene rubber, EPDM
Etc.) Very useful for adhesive tapes (sheets) based on foams such as foams, vinyl chloride foams, polyethylene foams, polypropylene foams, phenolic foams, urea foams, etc. Polyurethane foam, polyethylene foam, rubber (chloroprene rubber, EPDM)
Etc.) Useful for foam substrates such as foams. Also, the adherend is not particularly limited, and is a metal plate of any material including a stainless steel plate, an aluminum plate, a steel plate, a copper plate, etc., a synthetic resin decorative plate such as a melamine plate, a phenol plate, a plywood, a single plate. In addition to a plate-like material such as a plate or a glass plate, it can be attached to a rod-like material, the surface of concrete or mortar, the surface of pottery or various molded products, or other plastics.

[0018]

[Production of acrylic copolymer (A)]

[Acrylic copolymer (A-I)] 66 parts of 2-ethylhexyl acrylate (A1), 0.1 part of hydroxyethyl methacrylate (A2), n-butyl acrylate (A3) 2
0 parts, acrylic acid (A3) 7.9 parts, vinyl acetate (A3) 6
Parts, 100 parts of ethyl acetate, and 0.1 part of azobisisobutyronitrile (AIBN) were charged into a flask equipped with a condenser, a stirrer, and a thermometer, heated to 90 ° C., and polymerized. After polymerizing for 7 hours while sequentially adding a polymerization catalyst solution in which 0.1 part of AIBN was dissolved, an acrylic copolymer (AI) having a weight average molecular weight of 650,000 was obtained.

[Acrylic copolymer (A-II)] 65 parts of 2-ethylhexyl acrylate (A1), 0.1 part of hydroxyethyl methacrylate (A2), 22 parts of n-butyl acrylate (A3), acrylic acid ( A3) 6.9 parts, vinyl acetate (A3) 6 parts, ethyl acetate 100 parts, azobisisobutyronitrile (AIBN) 0.1 part were charged into a flask equipped with a condenser, a stirrer and a thermometer, and heated to 90 ° C. The polymer was heated and polymerized, and AIBN was added to 10 parts of toluene during the polymerization.
While successively adding a polymerization catalyst solution in which 0.1 part was dissolved, 7
After polymerization for an hour, an acrylic copolymer (A-II) having a weight average molecular weight of 680,000 was obtained.

[Acrylic copolymer (A-III)] 63 parts of 2-ethylhexyl acrylate (A1), 0.1 part of hydroxyethyl methacrylate (A2), 1.0 part of allyl glycidyl ether (A2), n- Butyl acrylate (A
3) 25 parts, acrylic acid (A3) 2.9 parts, vinyl acetate (A
3) 6 parts, 100 parts of ethyl acetate and 0.1 part of azobisisobutyronitrile (AIBN) were charged into a flask equipped with a condenser, a stirrer and a thermometer, heated to 90 ° C. and polymerized. After polymerizing for 7 hours while sequentially adding a polymerization catalyst solution in which 0.1 part of AIBN was dissolved in 10 parts of toluene, an acrylic copolymer (A-III) having a weight average molecular weight of 620,000 was obtained.

Example 1 100 parts of the above acrylic copolymer (AI), 5 parts of xylene resin (methylol group content 2.5%) (B), 1.5 parts of chlorinated polypropylene (C), 20 parts of disproportionated rosin ester (D), isocyanate-based crosslinking agent ("Coronate L-55E", manufactured by Nippon Polyurethane Industry Co., Ltd.)
(E) 2.0 parts was mixed and stirred to obtain the pressure-sensitive adhesive composition of the present invention. [Evaluation of physical properties] Toluene was added to the obtained pressure-sensitive adhesive composition to form a solution having a solid content of 40%.
And then dried at 80 ° C for 1 minute.
0 mm thick ether type urethane foam sheet (expansion ratio 30
)) (Transferred) to obtain an adhesive sheet of a foam base material. The following evaluation was performed using such an adhesive sheet. (Adhesive force) Using SUS304 (No. 280 polished product) and polypropylene resin (PP) as a test plate (width 25 mm, length 200 mm), measurement of adhesive force according to JIS Z 0237 except that measurement is performed 20 minutes after crimping. The measurement was performed according to the method.

(Curved Surface Adhesive Strength) An adhesive sheet piece having a width of 25 mm and a length of 120 mm was stuck on a curved surface of an iron cylinder having a diameter of 75 mmφ and allowed to stand for 17 hours under normal conditions (23 ° C., 65% humidity).
It was further kept at 80 ° C. for 4 hours, and the degree of peeling was evaluated by the length in the long side direction. (Softening point) An adhesive sheet piece having a width of 25 mm and a length of 75 mm was stuck on a test plate of SUS304 (No. 280 polished product), allowed to stand in a normal state (same as above) for 15 minutes, and one end of the test plate was stopped with a stopper. So that the adhesive sheet piece hangs vertically,
Attach a 310g weight to the end of the folded part,
Hold at 8 ° C for 15 minutes, then raise the temperature at 3 ° C / 5 minutes,
Except for measuring the temperature when the adhesive sheet piece falls,
The measurement was performed according to the measurement of the retention force of IS Z 0237. (Heat 90 ° holding power) SUS304 (No. 280 polished product)
A piece of an adhesive sheet having a width of 50 mm and a length of 75 mm was stuck to a test plate having a length of 120 mm, left in a normal state (same as above) for 24 hours, kept at 80 ° C. for 1 hour, and further kept at 80 ° C. for 1 hour.
The measurement was carried out in accordance with JIS Z 0237 measuring method for holding force except that a load of 00 g was applied and the peeling length after 60 minutes was measured.

(Initial adhesive strength) Cube weight 1 cm square 1
After contacting 0 g with the adhesive surface of the test plate for 3 seconds, 200 m
It was pulled up at a speed of m / min, and the adhesive strength (tensile strength) (g / cm ² ) at that time was measured at 5 ° C. and 20 ° C. Examples 2 to 5 and Comparative Examples 1 to 2 Using the above-mentioned acrylic copolymers (A-I to III), a pressure-sensitive adhesive composition was obtained according to Example 1 with a compounding composition as shown in Table 1 according to Example 1. Evaluation was performed in the same manner as in Example 1. In Examples 3 and 4, an ester type urethane foam sheet having an expansion ratio of 30 was used as a base material. In Example 5, the expansion ratio was 30.
A double-fold foamed polyethylene sheet was used as a base material. Table 2 shows the evaluation results of the examples and the comparative examples.

[0024]

[Table 1] (A) Component (B) Component (C) Component (D) Component (E) Component Type Amount Type Amount Type Amount Type Amount Type Amount Example 1 AI 100 BI 5 CI 1.8 DI 20 EI 1.5 〃 2 A -II 100 BI 8 CI 1.0 D-II 20 EI 2.0 ３ 3 A-III 100 BI 5 C-II 1.8 DI 20 E-II 1.5 〃 4 AI 100 BI 5 CI 1.5 D-II 20 EI 1.5 〃 5 AI 100 BI 3 CI 1.0 D-II 20 EI 1.5 Comparative Example 1 Without blending AI 100 CI 1.8 DI 20 EI 1.5 〃2 Without blending AI 100 BI 5 DI 20 EI 1.5 Note) Abbreviations are as follows. BI: a xylene resin containing 2.5% of methylol groups CI: chlorinated polypropylene C-II; chlorinated polyethylene EI: isocyanate-based cross-linking agent (Nippon Polyurethane Industry Co., Ltd., “Coronate L- 55E ") E-II; Aliphatic polyamine-based crosslinking agent (5% solution in toluene) DI: Disproportionated rosin ester D-II: Polymerized rosin ester

[0025]

[Table 2] Adhesive force Curved surface adhesive force Softening point Heat resistant 90 degree holding force Initial adhesive force (g / 25 mm) (mm) (° C) (mm) (g / cm ² ) Example 1 1150/1080 0 118 30 800 / 900 〃2 1100/1000 0 110 40 810/920 ３3 1050/1070 0 120 35 780/800 〃4 1120/1070 0 110 30 800/850 〃5 1200/1050 0 115 40 880/790 Comparative example 1 950 / 850 2.0 100 Dropped in 40 minutes 400/450 〃 2 800/750 2.0 80 Dropped in 35 minutes 470/500 Note) The adhesive strength is the initial adhesive strength of (SUS board adhesive strength / PP board adhesive strength) The force represents (initial adhesion at 20 ° C./initial adhesion at 5 ° C.), respectively.

[0026]

Since the pressure-sensitive adhesive composition of the present invention essentially comprises the components (A) to (E) as described above, it has excellent adhesiveness not only to a flat surface but also to a curved surface. Is excellent in heat resistance and initial (normal temperature / low temperature) adhesion, and is useful for adhesive tapes (sheets) using general substrates such as kraft paper, cloth, PET, styrene, and vinyl chloride. In particular, polyurethane foam, polystyrene foam, A
BS foam, rubber (chloroprene rubber, EPDM
Etc.) Very useful for adhesive tapes (sheets) based on foams such as foams, vinyl chloride foams, polyethylene foams, polypropylene foams, phenolic foams, urea foams, etc. Polyurethane foam, polyethylene foam, rubber (chloroprene rubber, EPDM)
Etc.) Useful for foam substrates such as foams.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI C09J 161: 18 123: 28 193: 04)

Claims (10)

[Claims] 1. A pressure-sensitive adhesive composition comprising an acrylic copolymer (A), a xylene resin (B), a chlorinated compound (C), a tackifier (D) and a cross-linking agent (E). . 2. An acrylic copolymer (A) having 60 to 99.9% by weight of an alkyl (meth) acrylate (A1) having 11 or more carbon atoms and 0.01 to 0.01% by weight of a functional group-containing monomer (A2). 40% by weight and other monomer (A3)
The pressure-sensitive adhesive composition according to claim 1, wherein a copolymer containing up to 39.9% by weight is used. 3. The pressure-sensitive adhesive according to claim 2, wherein the functional group-containing monomer (A2) is a monomer containing any one of a carboxyl group, a hydroxyl group, a glycidyl group and an acetoacetyl group. Composition. 4. The acrylic copolymer (A) has a weight average molecular weight of 400,000 or more.
The pressure-sensitive adhesive composition according to any one of the above. 5. The xylene resin (B) contains 5.0% by weight or less of methylol groups.
4. The pressure-sensitive adhesive composition according to any one of 4. 6. The content of the xylene resin (B) is from 0.5 to 0.5.
The pressure-sensitive adhesive composition according to any one of claims 1 to 5, wherein the content is 50% by weight. 7. The adhesive composition according to claim 1, wherein the chlorinated compound (C) is chlorinated polypropylene. 8. The content of the chlorinated compound (C) is from 0.5 to 0.5.
The adhesive composition according to any one of claims 1 to 7, wherein the content is 20% by weight. 9. The pressure-sensitive adhesive composition according to claim 1, which is applied to a foam base material to produce a pressure-sensitive adhesive tape. 10. The pressure-sensitive adhesive composition according to claim 9, wherein the foam base material is any one of a urethane foam, a polyethylene foam, and a rubber foam.