JPH0753929A - Pressure-sensitive adhesive tape - Google Patents

Abstract

PURPOSE:To obtain a pressure-sensitive adhesive tape which is excellent in the balance between the adhesive strength under peeling and the one under shear and also in impact resistance. CONSTITUTION:A pressure-sensitive adhesive tape is obtd. by forming a pressure- sensitive adhesive layer on both sides of a substrate made by laminating a low-modulus foam layer having a foaming ratio of 1.05-3 and an apparent 100% modulus at 23 deg.C of 0.3-5kg/cm<2> to a high-modulus foam layer having a foaming ratio of 2-10 and an apparent 100 % modulus at 23 deg.C of 7-50kg/cm<2>.

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 tape having a laminated foam as a support and pressure-sensitive adhesive layers provided on both sides of the support.

[0002]

2. Description of the Related Art Butyl rubber, chloroprene rubber,
A pressure-sensitive adhesive tape comprising a support made of a foamed material of acrylic rubber, polyethylene, etc., and pressure-sensitive adhesive layers provided on both sides of the support is, for example, a wall, a ceiling, a surface of a mechanical device, or the like. It is widely used for fixing mirrors, hooks, nameplates, etc.

The pressure-sensitive adhesive tape used for such purposes has an external force applied to a fixed member such as a mirror, a hook, and a name plate dispersed and relaxed by the foam structure of the support, The adhesive fixing force is retained.

[0004]

However, the conventionally known pressure-sensitive adhesive tape using a foam as a support is suitable for an adherend having a rough surface, an uneven surface, particularly an uneven surface having a step, a curved surface, or the like. On the other hand, it is difficult to balance the peel adhesive strength and the shear adhesive strength, and the impact resistance is poor, especially at low temperatures.
There was a problem that the fixed member often fell off.

In view of the above-mentioned conventional circumstances, the present invention has an excellent balance property of peeling adhesive force and shearing adhesive force, and also has excellent impact resistance, so that the adhesive fixing force of members can be stably exhibited. It is intended to provide pressure-bonded tape.

[0006]

Means for Solving the Problems The inventors of the present invention have made extensive studies in order to achieve the above-mentioned object. As a result, the support made of foam has a specific laminated structure, whereby peeling adhesive force and shear adhesion are improved. Knowing that a pressure-sensitive adhesive tape with excellent balance properties with force and improved impact resistance can be obtained,
The present invention has been completed.

That is, according to the present invention, the expansion ratio is 1.05.
~ 3 times the apparent 100% module at 23 ° C is 0.
A laminated foam comprising a low-modulus foam layer of 3 to 5 kg / cm ² and a high-modulus foam layer having an expansion ratio of 2 to 10 and an apparent 100% module at 23 ° C. of 7 to 50 kg / cm ^2. The present invention relates to a pressure-sensitive adhesive tape comprising a support and pressure-sensitive adhesive layers provided on both sides of the support.

[0008]

The support used in the present invention comprises a laminated foam comprising a low-modulus foam layer and a high-modulus foam layer, which has a two-layer structure in which only one of the above layers is laminated. There is a three-layer structure in which a low-modulus foam layer is laminated on both sides of a high-modulus foam layer, that is, a San-Gerci structure, and in some cases, a multi-layer structure in which the above two layers are alternately laminated in four or more layers. Be done.

The low modulus foam layer has a foaming ratio of 1.0.
It is necessary that the apparent 100% modulus at 5 to 3 times and 23 ° C is 0.3 to 5 kg / cm ² , and more preferably the expansion ratio is 1.1 to 2 times and the apparent 100 at 23 ° C.
The% module is preferably 0.4 to 3 kg / cm ² . If the expansion ratio is lower than 1.05 times, the peeling adhesive strength will decrease,
When it is higher than 3 times, the shear adhesive strength is lowered. Further, the above Mojiyurasu is 0.3 Kg / cm ² less than Te - inferior in workability at the time of up cutting, larger than 5Kg / cm ^2, rough surface adhesiveness is particularly deteriorated.

The high modulus foam layer has a foaming ratio of 2-1.
0 to 100% apparent module at 23 ° C is 7-5
It is necessary that the amount is 0 kg / cm ² , more preferably the expansion ratio is 3 to 8 times, and the apparent 100% module at 23 ° C. is 8 to 40 kg / cm ² . If the expansion ratio is lower than 2 times, the impact resistance is lowered, especially the adhesiveness to uneven surfaces having steps is deteriorated, and if it is higher than 10 times, the peel adhesion strength is lowered. If the module is less than 7 kg / cm ² , the workability during tape bonding will be poor and 50 kg / cm ^2.
If it is larger than cm ² , the peel adhesion strength will decrease.

In the present invention, the above specific expansion ratio and 1
When a low-modulus foam layer having a 00% modulus and a high-modulus foam layer are laminated, excellent balance characteristics of peel adhesive strength and shear adhesive strength, particularly high peel adhesive strength, and improved impact resistance are obtained. For the first time, we have found that sex is obtained.

Such a low-modulus foam layer and a high-modulus foam layer are prepared by appropriately adding a compounding agent such as a foaming agent, a vulcanizing agent, a vulcanization accelerator, a softening agent, a filler and a pigment to a base polymer. It can be formed by vulcanizing and foaming. By adjusting the selection of the base polymer and the addition amount of the foaming agent, the vulcanizing agent, etc., the expansion ratio and the apparent 10
0% module can be set in the above range.

The base polymer is not particularly limited, and natural rubber, isoprene rubber, butadiene rubber, butyl rubber, chloroprene rubber, EPM (ethylene-propylene polymer), EPDM (ethylene-propylene-diene-terpolymer), Chlorinated polyethylene, ethylene-
Various polymers such as vinyl acetate copolymer, nitrile rubber, urethane rubber, acrylic rubber, epichlorohydrin rubber, silicone rubber and fluorine rubber are used.

The thickness of the low-modulus foam layer and the high-modulus foam layer depends on the balance characteristics of the peel adhesive force and the shear adhesive force,
It is preferable to set it in a predetermined range in order to obtain good results in improving the impact resistance and the rough surface adhesion. Generally, the low modulus foam layer has a thickness of 0.05 to 1 mm, preferably 0.1 to
0.5 mm, the thickness of the high modulus foam layer is 0.1-2 mm,
Preferably, it is 0.2 to 1 mm, and the value of (thickness of low modulus foam layer / thickness of high modulus foam layer) is 0.05 to 2,
It is preferably 0.1 to 1.5.

In order to laminate the low modulus foam layer and the high modulus foam layer, for example, both layers may be pressure laminated under heating or non-heating, or may be adhesively laminated using an adhesive. In the adhesive lamination, the same adhesive as the pressure-sensitive adhesive layer provided on both sides of the support may be used. The total thickness of the laminated foam produced in this manner can be appropriately set depending on the purpose of use, but it is generally 0.3 to 3 mm.

In the present invention, the pressure-sensitive adhesive layers provided on both sides of the support are known pressure-sensitive adhesives applied to general adhesive tapes such as rubber type, silicone type, vinyl acetate type and acrylic type. The adhesive can be widely used. The pressure-sensitive adhesive is layered on both sides of the support so that the pressure-sensitive adhesive usually has a thickness of 20 to 200 μm on one side.

In the acrylic pressure-sensitive adhesive, an acrylic polymer, that is, a homopolymer or copolymer of (meth) acrylic acid alkyl ester whose alkyl group generally has 1 to 14 carbon atoms, or the above-mentioned (meth) ) A copolymer of an alkyl acrylate and a monomer such as (meth) acrylic acid, (meth) acrylonitrile, vinyl acetate, N-vinyl-2-pyrrolidone or styrene is used.

As the silicone-based pressure-sensitive adhesive, silicone rubber such as methyl vinyl silicone rubber, phenyl silicone rubber, fluorosilicone rubber, and polyurethane silicone rubber is used. As the rubber pressure-sensitive adhesive, various rubbers such as natural rubber, styrene-butadiene rubber, polyisobutylene rubber, polyisoprene rubber, and chloroprene rubber are used.

These pressure-sensitive adhesives include, in addition to the above-mentioned acrylic polymer and base polymer such as silicone rubber, conventionally known additives such as tackifiers, anti-aging agents,
Various additives such as colorants and fillers may be blended. Also, use cross-linking monomers such as polyfunctional vinyl compounds, add external cross-linking agents such as polyisocyanate compounds, polyepoxy compounds, peroxides, irradiate radiation such as ultraviolet rays and electron beams. Then, appropriate crosslinking treatment may be performed.

[0020]

As described above, the pressure-sensitive adhesive tape of the present invention has an excellent balance between the peel adhesive force and the shear adhesive force and also has excellent impact resistance. It is possible to easily follow and deform an adherend such as a surface, in particular, an uneven surface having a step or a curved surface, to secure an adhesive area, and to stably exert an adhesive fixing force of a member for a long period of time.

[0021]

EXAMPLES Next, examples of the present invention will be described to more specifically describe. In the following, "parts" means "parts by weight".

Example 1 The thickness produced by the following method was 0.23 mm, the expansion ratio was 1.15 times, and the 100% module at 23 ° C. was 2.4 Kg.
/ Cm ² acrylic rubber foam (low modulus foam layer)
And the thickness is 0.8mm, the expansion ratio is 8 times, 10 at 23 ℃
A commercially available polyethylene foam (high modulus foam layer) having a 0% module of 17 kg / cm ² was laminated under pressure without heating to obtain a laminated foam.

<Preparation of Acrylic Rubber Foam> Acrylic rubber ["Toa Akron PS22 manufactured by Toa Paint Co., Ltd.
0 "] 100 parts was dissolved in 600 parts of toluene, and 1 part of a foaming agent [" Matsumoto Microsphere F50D "manufactured by Matsumoto Yushi-Seiyaku Co., Ltd.], trimethylolpropane-tolylene diisocyanate adduct 3 The parts were mixed and dissolved to obtain an acrylic rubber solution. This solution was applied on a separator so that the thickness after drying was 200 μm, and then 80
Dry at ℃ for 3 minutes, then heat at 130 ℃ for 3 minutes,
By foaming, an acrylic rubber-based foam was produced.

Next, using the above laminated foam as a support,
A sheet-shaped pressure-sensitive adhesive layer formed by the following method was attached to both surfaces of the sheet to prepare a pressure-sensitive adhesive tape.

<Formation of sheet-like pressure-sensitive adhesive layer> 75 parts of 2-ethylhexyl acrylate and N-vinyl-2- were placed in a reaction vessel equipped with a cooling pipe, a nitrogen introducing pipe, a thermometer and a stirrer. Pyrrolidone 19 parts, methacrylic acid 6 parts, 2,2
0.1 parts of ′ -azobisisobutyronitrile and 100 parts of ethyl acetate were added and reacted at 60 ° C. for 12 hours to obtain a polymer solution. To 100 parts of the solid content of this polymer solution, tetraglycidyl meta-xylenediamine 0.0
5 parts were added and mixed, and the thickness after drying was 7 on a separator.
It was applied so as to have a thickness of 0 μm and dried at 100 ° C. for 3 minutes to form a sheet-like pressure-sensitive adhesive layer.

Example 2 The acrylic rubber foam (low modulus foam layer) prepared in Example 1 was placed on both sides of the commercially available polyethylene foam (high modulus foam layer) used in Example 1 without heating. Then, it was pressure-laminated to obtain a laminated foam having a Saint-Gerchi structure. This laminated foam was used as a support, and the sheet-shaped pressure-sensitive adhesive layer formed in Example 1 was attached to both surfaces of the support to prepare a pressure-sensitive adhesive tape.

Example 3 The thickness produced by the following method was 1 mm and the expansion ratio was 2.5.
2 times, the epichlorohydrin rubber type foam (low modulus foam layer) having a 100% modulus at 2.8 kg / cm ² and the commercially available polyethylene foam (high modulus foam layer) used in Example 1 were used. The sheet formed in Example 1
The laminated foamed body was obtained by pasting together via a pressure-sensitive adhesive layer having a tongue shape. This laminated foam was used as a support, and the sheet-shaped pressure-sensitive adhesive layer formed in Example 1 was attached to both surfaces of the support to prepare a pressure-sensitive adhesive tape.

<Preparation of Epichlorohydrin Rubber Foam> 100 parts of epichlorohydrin rubber [“Epichroma CG” manufactured by Daiso Corp.], 20 parts of carbon black,
50 parts calcium carbonate, DOP (dioctyl phthalate)
20 parts, 2 parts ethylene thiourea, blowing agent (N, N
-Dinitropentamethylenetetramine) 1.5 parts, a urea foaming aid 1 part, a polymer of 2,2,4-trimethyl-1,2-dihydroquinoline 3 parts and stearic acid 1 part. It was vulcanized and foamed to prepare an epichlorohydrin rubber-based foam.

Comparative Example 1 The commercially available polyethylene foam (high modulus foam layer) used in Example 1 alone was used as a support, and both sides of Example 1 were used.
The sheet-shaped pressure-sensitive adhesive layer formed in step 1 was bonded to produce a pressure-sensitive adhesive tape.

Comparative Example 2 The thickness produced by the following method was 0.8 mm and the expansion ratio was 4
Double, an acrylic rubber foam having a 100% module at 23 ° C. of 0.8 kg / cm ² (low module foam layer) and the commercially available polyethylene foam used in Example 1 (high module foam layer). Then, they were laminated under pressure without heating to obtain a laminated foam. This laminated foam was used as a support, and the sheet-shaped pressure-sensitive adhesive layer formed in Example 1 was attached to both surfaces of the support to prepare a pressure-sensitive adhesive tape.

<Preparation of Acrylic Rubber Foam> Example 1
In producing the acrylic rubber-based foamed product, a foaming agent ["Matsumoto Microsphere F50 manufactured by Matsumoto Yushi-Seiyaku Co., Ltd.
D ”] was changed to 30 parts to prepare an acrylic rubber-based foam in the same manner as in Example 1.

Comparative Example 3 The acrylic rubber foam (low modulus foam layer) prepared in Example 1 alone was used as a support, and the sheet-like pressure-sensitive adhesive layer formed in Example 1 was adhered to both surfaces thereof. Together, a pressure sensitive adhesive tape was produced.

The pressure-sensitive adhesive tapes of Examples 1 to 3 and Comparative Examples 1 to 3 were examined for peel adhesive strength, shear adhesive strength and impact resistance in the following manner. The results are shown in Table 1 below.

<Peeling Adhesion> A 25 μm-thick polyester film is attached to a pressure-sensitive adhesive tape having a size of 20 mm × 100 mm, which is then sandpaper (# 280).
2 kg of roller was pressed back and forth to the stainless steel plate sanded in 1st, left for 20 minutes, and the force required for peeling (180 degree peeling) was applied at a pulling speed of 300 mm /
Min, 23 ° C., 65% RH.

<Shearing adhesive strength> A pressure-sensitive adhesive tape having a size of 10 mm × 10 mm is bonded between aluminum plates having a size of 20 mm × 100 mm and a thickness of 0.5 mm, and a roller of 2 kg is attached. After pressure-bonding by one reciprocating method and leaving it for 20 minutes, its shear adhesive strength is 50 mm / min in tensile speed, 23 ° C., 65% RH
It was measured under the conditions of.

<Impact resistance> A pressure-sensitive adhesive tape having a size of 10 mm × 10 mm, a size of 60 mm × 60 mm, and a thickness of 2 mm
Bakelite plate and 50mm x 50mm SUS304 with 0.5mm thickness and 0.5mm thickness are pasted together and crimped by a method of reciprocating a 2Kg roller once and left at 23 ° C for 24 hours. Then, the mixture was allowed to stand at 0 ° C. for 24 hours, dropped from a height of 80 cm onto concrete, and the number of times until destruction was measured.

[0037]

[Table 1]

As is clear from the results shown in Table 1, the pressure-sensitive adhesive tapes of Examples 1 to 3 of the present invention have a peeling adhesive strength as compared with the pressure-sensitive adhesive tapes of Comparative Examples 1 to 3. It can be seen that it has an excellent balance property between the adhesive strength and the shear adhesive strength, and that a particularly high peel adhesive strength is obtained and the impact resistance is also excellent.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshinao Kitamura 1-2-1, Shimohozumi, Ibaraki City, Osaka Prefecture Nitto Denko Corporation

Claims (2)

[Claims] 1. A low modular foam layer having a foaming ratio of 1.05 to 3 times and an apparent 100% module at 23 ° C. of 0.3 to 5 kg / cm ² , and a foaming ratio of 2 to 10 times, 23.
The apparent 100% module at 7 ℃ is 7 to 50 kg / cm ^2.
A pressure-sensitive adhesive tape comprising a laminated foam having a high modulus foam layer as a support, and pressure-sensitive adhesive layers provided on both sides of the support. 2. The low modulus foam layer has a thickness of 0.05 to.
1mm, the thickness of high modulus foam layer is 0.1-2mm,
The pressure-sensitive adhesive tape according to claim 1, wherein the value of (thickness of low-modulus foam layer / thickness of high-modulus foam layer) is 0.05 to 2.