JP2002356660A - Double-coated adhesive tape and bonded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a double-coated adhesive tape which is excellent in strength against delamination from an adhered matter and adaptability to a complicated shape, and a float or a peeling-free bonded product using the double-coated adhesive tape. SOLUTION: The double-coated adhesive tape comprises an adhesive layer laminated over the both sides of a curved surface-adaptable nonwoven fabric, wherein the nonwoven fabric has a longitudinal elongation and a lateral strain of 100% or more and an stress of 3 N/cm or less at 100% strain. The bonded product can be produced by bonding a polyolefine material by the double-coated adhesive tape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-sided pressure-sensitive adhesive tape suitably used for bonding interior materials and the like, and a bonded body bonded using the double-sided tape.

[0002]

2. Description of the Related Art In recent years, as part of environmental protection, demand for environmentally friendly plastics has been rapidly increasing in the course of recycling vinyl chloride resin. Under such a social environment, olefination of resin members is rapidly progressing particularly in the fields of automobile parts, home electric appliances, packaging materials and the like. However, since an olefin resin, which is a nonpolar resin, is generally a difficult adherend, it has been considered difficult to join olefin resin-based members with a general-purpose acrylic resin-based pressure-sensitive adhesive having a relatively high polarity. Was. Therefore, as a method of joining olefin resin-based members, fitting, screwing, fusion, hot-melt adhesive, and the like have been common.

[0003] However, the above-mentioned joining method has potential problems such as a long joining time and a variation in quality. In order to solve such a problem, for example, Japanese Patent Application Laid-Open
As described in Japanese Patent No. 27440, a method using an adhesive tape provided with an adhesive layer on a nonwoven fabric substrate has been the mainstream of the conventional method in terms of simplicity.

[0004]

However, according to the study of the present inventor, the pressure-sensitive adhesive tape based on the nonwoven fabric as described above shows that when a certain stress acts on the joined body, the peeling stress is increased on the adherend. Since it is concentrated on the interface between the adhesive and the adhesive, split peeling or the like may occur, and the peel strength is not always sufficient. In addition, in general, an adhesive tape based on a nonwoven fabric is inferior in conformity to irregularities, so when used for an adherend of a complicated shape having a curved surface such as a vehicle interior material,
There was a drawback that the joint was likely to float or peel off.

In view of the above findings obtained by the present inventors, an object of the present invention is to provide a double-sided pressure-sensitive adhesive tape having excellent peel strength from an adherend and excellent conformability to a complicated shape. An object of the present invention is to provide a joined body that is less likely to be lifted or peeled off. The double-sided pressure-sensitive adhesive tape of the present invention includes a double-sided pressure-sensitive adhesive sheet.

[0006]

In order to achieve the above object, the invention according to claim 1 provides a double-sided pressure-sensitive adhesive tape comprising a nonwoven fabric having curved surface followability, and pressure-sensitive adhesive layers provided on both sides. The invention according to claim 2 provides the double-sided pressure-sensitive adhesive tape according to claim 1, wherein the nonwoven fabric has an elongation in the longitudinal and lateral directions of 100% or more, respectively, and a 100% elongation strength of 3 N / cm or less. .

[0007] The invention according to claim 3 is an acrylic system wherein the pressure-sensitive adhesive layer is copolymerized by containing an alkyl (meth) acrylate having an alkyl group having 4 to 10 carbon atoms in a proportion of 30 to 95% by weight. The double-sided pressure-sensitive adhesive tape according to claim 1, comprising an acrylic pressure-sensitive adhesive containing a copolymer as a main component. Further, the invention described in claim 4 is based on claims 1 to
3. A joined body formed by joining a polyolefin-based member using the double-sided pressure-sensitive adhesive tape according to any one of 3.

Hereinafter, the present invention will be described in more detail. The nonwoven fabric used in the present invention is not particularly limited as long as it has a curved surface following property.
A urethane resin-based nonwoven fabric having a thickness of 0 μm or less, a polyolefin resin-based nonwoven fabric, a polyester resin-based nonwoven fabric, and the like can be given. In particular, the elongation of the nonwoven fabric in the vertical and horizontal directions is 100
% Or more, and those having a 100% elongation strength of 3 N / cm or less.

When the elongation is less than 100%, when a member such as a polyethylene resin foam sheet is attached to a molded article having a complicated shape such as an interior material for a vehicle in a circular or non-linear manner, Wrinkles and the like easily enter the inside of the bent portion. Further, if the 100% elongation exceeds 3 N / cm, peeling may occur due to tensile stress at the time of sticking. The upper limit of the elongation and the lower limit of the 100% elongation are not particularly recognized. However, if the elongation is too high, the workability of the sticking work is liable to be deteriorated easily, and the 100% elongation is too low. Care must be taken because the follow-up property when sticking to curved surfaces and the like is poor.

The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer according to the present invention comprises:
There is no particular limitation, and an acrylic pressure-sensitive adhesive containing, as a main component, an acrylic copolymer obtained by copolymerizing an alkyl (meth) acrylate having an alkyl group having 4 to 10 carbon atoms in a proportion of 30 to 95% by weight. It is preferred that The content of the alkyl (meth) acrylate is 95% by weight.
If the ratio exceeds the above range, the heat resistance may be poor and the usability at low temperatures may be deteriorated.

Examples of the alkyl (meth) acrylate include n-butyl acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, n-octyl (meth) acrylate, nonyl (meth) acrylate, and decyl (meth) acrylate. ) Alkyl (meth) acrylates such as acrylate and the like, and these can be used alone or in combination.

The above-mentioned acrylic copolymer may be obtained by copolymerizing an olefin polymer having a polymerizable unsaturated double bond at a terminal in order to increase the adhesion to polyolefin. The olefin polymer having a polymerizable unsaturated double bond is not particularly limited as long as it has a polymer structure comprising a double bond copolymerizable with another vinyl monomer and an olefin skeleton. Examples of the skeleton include an ethylene-butylene random copolymer and an ethylene-propylene copolymer.

The acrylic copolymer can be produced by a conventionally known polymerization method. For example, it may be solution-polymerized in a solvent or may be bulk-polymerized. As the bulk polymerization method, a photopolymerization method that does not require drying of an organic solvent or water as a solvent in industrial production is suitable. The acrylic copolymer obtained by the photopolymerization method of irradiating ultraviolet rays has a good reproducibility of the molecular weight, and therefore, an acrylic pressure-sensitive adhesive containing this copolymer as a main component has good physical properties.

The acrylic pressure-sensitive adhesive of the present invention preferably contains the above-mentioned acrylic copolymer as a main component and is added with a conventionally known crosslinking agent in order to improve heat resistance and creep properties. As the crosslinking agent, for example, an isocyanate-based, epoxy-based, or aziridine-based crosslinking agent is frequently used. Further, it is preferable that a copolymerizable monomer having a polar group is introduced as a component into the acrylic copolymer so that the crosslinking reaction proceeds with such a crosslinking agent without fail.

Examples of such a copolymerizable monomer include styrene-based monomers such as styrene, α-methylstyrene, o-methylstyrene and p-methylstyrene; carboxylic acid vinyl esters such as vinyl acetate: acrylic acid and methacrylic acid. Vinyl group-containing carboxylic acid or carboxylic anhydride such as acid: 2-hydroxyethyl (meth) acrylate, hydroxyl group-containing vinyl monomer such as 4-hydroxybutyl acrylate: (meth) acrylonitrile, N
And nitrogen-containing monomers such as vinylpyrrolidone. Above all, acrylic acid and methacrylic acid having a carboxylic acid, 2-hydroxyethyl (meth) acrylate having a hydroxyl group, and the like are more preferable in forming a crosslinked structure derived from a reaction with an isocyanate-based crosslinking agent or an epoxy-based crosslinking agent. Used for

Further, in order to form a crosslinked structure, a monomer having two or more copolymerizable unsaturated double bonds in a molecule may be copolymerized. Examples of such a monomer include hexanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, urethane acrylate, and polyester acrylate.

The acrylic pressure-sensitive adhesive of the present invention contains the above-mentioned acrylic copolymer as a main component, and if necessary, further comprises
Tackifiers, plasticizers, softeners, inorganic and organic fillers, pigments, dyes and the like are appropriately blended and used. The tackifier is not particularly limited, and includes conventionally known rosin resins, modified rosin resins, terpene resins, terpene phenol resins, C5 and C9 petroleum resins, and hydrogenated products thereof. These can be used alone or in combination of two or more.

The thickness of the adhesive layer in the present invention is not particularly limited, but is preferably from 40 to 1000 μm, and more preferably from 70 to 600 μm. 40
When it is less than μm, it is difficult to follow irregularities on the surface of the adherend, and when it exceeds 1000 μm, the flexibility of the nonwoven fabric is impaired.

The method for producing the double-sided pressure-sensitive adhesive tape of the present invention is not particularly limited. For example, two release papers each having an adhesive layer provided on one surface are prepared, and one release paper is provided on one surface of a nonwoven fabric having a curved surface following property. Are laminated to form an adhesive layer by transfer, and the other surface is similarly formed by a method of forming an adhesive layer. The joined body of the present invention is obtained by joining polyolefin-based members, and one of the joined bodies is typically a polyolefin resin molded article and the other is a polyolefin resin foam, but one is a polyolefin resin molded article or a polyolefin resin. It may be a foam, the other of which may be metal or glass.

[0020]

Next, the joined body of the present invention will be described.
This will be described below with reference to the drawings. FIG. 1 is a schematic view showing one example of the joined body of the present invention, and shows an interior material for an automobile. The joined body of the present invention is joined using the double-sided pressure-sensitive adhesive tape according to any one of claims 1 to 3, and is a member 1
And the member 2 are joined with the double-sided adhesive tape 3 of the present invention.

The member 1 is, for example, a foamed polypropylene resin sheet used as a surface covering material of an interior material, and has a role as a cushioning material. The member 2 is a polyolefin resin molded product that has been thermoformed in advance. In order to manufacture the joined body of the present invention, for example, one of the release papers of the double-sided adhesive tape 3 is peeled off from the polyolefin resin molded article 2 and the exposed adhesive layer is attached along the corner portion, and the other adhesive layer is attached to the other adhesive layer. It is advisable to place the polypropylene resin foam sheet 1 and press it on.

(Function) In the double-sided pressure-sensitive adhesive tape of the present invention, by using a nonwoven fabric having a curved surface followability, it is easy to follow an adherend having a complicated shape, and in addition, a peeling force acts on a joint portion. In this case, since the concentration of stress at the interface between the adherend and the pressure-sensitive adhesive can be significantly reduced, the peel strength from the adherend can be greatly improved. For this reason, even if the adherend is an olefin resin-based member, it is possible to obtain a sufficient peel strength. In addition, the elongation of the nonwoven fabric is 100% or more, and the 100% elongation strength is 3%.
When the value is N / cm or less, the above-mentioned effect is further ensured. Since the joined body of the present invention is joined by using the double-sided pressure-sensitive adhesive tape having the above-described characteristics, a joined body in which floating or peeling is less likely to occur at the joining interface can be obtained.

[0023]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples. The present invention is not limited only to the following examples. Further, “parts” means “parts by weight”. (Example 1) 30 parts of butyl acrylate, 60 parts of 2-ethylhexyl acrylate and 2 parts of acrylic acid were placed in a separable flask equipped with a cooling tube, a thermometer and a stirrer.
It was dissolved in ethyl acetate so that the total amount was 55/45 by weight with respect to ethyl acetate, and 0.062 part of benzoyl peroxide was added as a polymerization initiator to the obtained solution.

This mixed solution was stirred at 80 ° C. for 8 hours under nitrogen reflux to carry out polymerization to obtain an acrylic copolymer solution.
Further, as a cross-linking agent, 2.0 parts of a modified tolylene diisocyanate trimethylolpropane (trade name "Coronate L" manufactured by Nippon Polyurethane Co., Ltd.) was added to 100 parts of the acrylic copolymer, and the mixture was mixed with an adhesive composition. Was prepared. The obtained pressure-sensitive adhesive composition is PE-coated with a knife coater.
After drying on a T film (thickness: 38 μm), the film is cast to a thickness of 75 μm, and then dried in a gear oven at 105 ° C. for 3 hours.
After drying for 2 minutes, both sides were adhered to a nonwoven fabric to obtain a double-sided adhesive tape. In addition, as the nonwoven fabric, urethane nonwoven fabric (manufactured by Kanebo Co., Ltd., trade name "Espancione UHO50",
The elongation and elongation strength described in Table 1 were used.

(Example 2) A double-sided pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 except that a stretchable polyolefin nonwoven fabric (trade name: Stratec AF70E, manufactured by Idemitsu Petrochemical Co., Ltd.) was used as the nonwoven fabric. Was.

(Example 3) 30 parts of butyl acrylate
60 parts of 2-ethylhexyl acrylate and 2 parts of acrylic acid were uniformly mixed, and 0.1 part of a photoinitiator (trade name “Ilkaguer 651” manufactured by Ciba Kaigi Co., Ltd.) was added.
After mass polymerization to a thickness of 75 μm using an ultraviolet lamp,
A double-sided adhesive tape was obtained by affixing to both sides of the nonwoven fabric. In addition, as the nonwoven fabric, a stretchable polyester nonwoven fabric (manufactured by Teijin Limited,
The trade name "R291") was used.

Example 4 As shown in FIG. 1, a member 1 and a member 2 were joined using the double-sided pressure-sensitive adhesive tape obtained in Example 1 to produce a joined body. As the member 1, a cross-linked foamed polyethylene foam having a thickness of 3 mm and a 20-fold expansion was used, and as the member 2, an olefin molded product having a thickness of 1.5 mm was used.

Example 5 A joined body was produced in the same manner as in Example 4 except that the double-sided pressure-sensitive adhesive tape obtained in Example 2 was used. (Example 6) A joined body was produced in the same manner as in Example 4 except that the double-sided pressure-sensitive adhesive tape obtained in Example 3 was used.

Comparative Example 1 A double-sided pressure-sensitive adhesive tape was obtained in the same manner as in Example 1, except that a pulp-based nonwoven fabric (trade name "SPC14", manufactured by Nippon Paper Industries) was used as the nonwoven fabric. (Comparative Example 2) A double-sided pressure-sensitive adhesive tape was obtained in the same manner as in Example 1, except that a polyester non-woven fabric (product name: Spunbond 20451 FLV, manufactured by Unitika Ltd.) was used as the non-woven fabric.

Comparative Example 3 A joined body was produced in the same manner as in Example 4 except that the double-sided pressure-sensitive adhesive tape obtained in Comparative Example 1 was used. Comparative Example 4 A joined body was produced in the same manner as in Example 4 except that the double-sided pressure-sensitive adhesive tape obtained in Comparative Example 2 was used.

The above Examples and Comparative Examples were evaluated by the following methods. (Evaluation method) 1. Elongation Measured in accordance with JIS L1096 "General textile test method". 2.100% elongation strength Measured in accordance with JISL1096 "General textile test method". 3. PP 90 degree peel adhesive strength According to JISZ0238, Examples 1 to 3 and Comparative Example 1
The double-sided pressure-sensitive adhesive tape obtained in Steps 2 to 2 was PP
(Polypropylene) affixed to the plate, tape back 25μm
After backing with a PET film, the film is pressed and reciprocated once with a 2 kg roller at a speed of 300 mm / min. Paste 2
After 4 hours, under the same environment, peeling speed 300
The adhesive strength was measured under the condition of mm / min.

4. 80 ° C. Constant Load Peeling Force A 20 mm wide and 50 mm long sample cut from the double-sided pressure-sensitive adhesive tape obtained in Examples 1 to 3 and Comparative Examples 1 and 2 was used.
2kg in PP (polypropylene) plate under 23 ℃ environment
After pressure-bonding with a roller at a speed of 300 mm / min, backing the tape back with a 25 μm PET film, leaving it for 24 hours, put it in an environment of 80 ° C., apply a load of 80 g to one end of the tape as shown in FIG. The peeling force was determined by measuring the amount of peeling after time. 5. Bonded body evaluation The bonded bodies obtained in Examples 4 to 6 and Comparative Examples 3 to 4 were 80
C. environment, left for 240 hours, then joined member 1
The state of floating and peeling at the joint surface between the member and the member 2 was visually confirmed. The measurement and evaluation results as described above were as shown in Tables 1 and 2.

[0033]

[Table 1]

[0034]

[Table 2] As is clear from Tables 1 and 2, in the examples of the present invention, while having high PP adhesive strength, having excellent peel strength even in the amount of peeling under a constant load, floating and peeling also occur in the joined body. It was found not to occur.

[0035]

As the double-sided pressure-sensitive adhesive tape of the present invention uses a nonwoven fabric having a curved surface followability, it can easily follow an adherend having a complicated shape, and can greatly improve the peel strength from the adherend. Even if the adherend is an olefin resin-based member, sufficient peel strength can be obtained. Also,
When the nonwoven fabric having a specific elongation and the elongation strength or the pressure-sensitive adhesive layer uses an acrylic pressure-sensitive adhesive containing a specific acrylic copolymer as a main component, the above effects can be more reliably exerted. Furthermore, since the joined body in the present invention is joined using the above-mentioned double-sided adhesive tape, even if a member having a complicated uneven shape or an olefin resin-based member is used, it floats or peels off at the joining interface. It becomes possible to obtain a joined body without any.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a joined body of the present invention.

FIG. 2 is a schematic diagram showing a method for measuring a constant load peeling force at 80 ° C. in an example.

[Explanation of symbols]

 1. Member 1 2. Member 2 3. Double-sided adhesive tape

Claims (4)

[Claims] 1. A double-sided pressure-sensitive adhesive tape comprising a nonwoven fabric having a curved surface followability property and pressure-sensitive adhesive layers provided on both sides. 2. The nonwoven fabric has an elongation of 10 and 10 in the longitudinal and transverse directions, respectively.
The double-sided pressure-sensitive adhesive tape according to claim 1, wherein the pressure-sensitive adhesive tape has a tensile strength of 0% or more and a 100% elongation strength of 3 N / cm or less. 3. A pressure-sensitive adhesive layer comprising, as a main component, an acrylic copolymer obtained by copolymerizing an alkyl (meth) acrylate having an alkyl group having 4 to 10 carbon atoms in a proportion of 30 to 95% by weight. 3. The double-sided pressure-sensitive adhesive tape according to claim 1, comprising an acrylic pressure-sensitive adhesive. 4. A joined body obtained by joining polyolefin-based members using the double-sided pressure-sensitive adhesive tape according to claim 1.