JPH093412A - Adhesive sheet having foamed substrate - Google Patents

Abstract

PURPOSE: To obtain an adhesive sheet capable of developing high adhesive strength, having decreased selectivity of adherend and exhibiting excellent versatility by lowering the modulus of a foamed substrate and controlling the extension to decrease the stress concentration on the bonding interface part. CONSTITUTION: This adhesive sheet is produced by forming a pressure-sensitive adhesive layer on a substrate consisting of a foamed elastomer preferably composed mainly of an epichlorohydrin rubber and having an elongation at break of 300-800% (preferably 500-700%) and a breaking strength of 1.0-15kg/cm<2> . The substrate is further compounded with a rubber reinforcing agent, a vulcanization agent, a foaming agent and an antioxidant as essential components.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet-like or tape-like adhesive sheet having a foamed base material having a pressure-sensitive adhesive layer on a foamed base material.

[0002]

2. Description of the Related Art Conventionally, adhesive sheets such as sheets and tapes in which a pressure-sensitive adhesive layer is provided on a substrate made of foam such as butyl rubber, chloroprene rubber, and synthetic resin have been available. Are known. According to these adhesive sheets with a foam substrate,
With respect to external force or vibration applied to the adhered and fixed member, by dispersing and relaxing the force with a base material made of foam,
Strong adhesive strength and strong fixability can be exhibited.

[0003]

However, the conventional adhesive sheets with a foam base material are members to be joined (adherends).
However, there is a problem in that the adhesive strength is remarkably reduced, and the member easily comes off when an external force is applied to the member. As a result, there has been a problem that the adherend to be used is restricted, that is, the adherend has selectivity.

This is because the module of the foam base material is generally much higher than the module of the adhesive, so that the external force applied to the attaching member is concentrated on the interface of the adhesive at the joint portion, and the interface of the adhesive is peeled off. It is presumed that the interface will be destroyed. Therefore, the adhesive strength of this type of adhesive sheet is largely dependent on the interfacial bonding force (affinity) between the adhesive and the adherend, resulting in adherent selectivity. .

In view of the above conventional circumstances, the present invention reduces the modulus of the foamed base material and adjusts the elongation to reduce the stress concentration at the joint interface portion and to the same level for various adherends. It is an object of the present invention to provide an adhesive sheet with a foaming base material, which has high adhesive strength, low adherence selectivity, and excellent versatility.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies in order to achieve the above object, and as a result, as a base material on which a pressure-sensitive adhesive layer is to be provided, have a low modulus and a suitable elongation. It has been found that by using a specific foamed elastomer having a tensile strength of 100 degrees, it is possible to obtain an adhesive sheet with a foamed base material, which has a small selectivity for an adherend and is excellent in versatility. It has been completed.

That is, the present invention uses as a base material a foamed elastomer having a breaking elongation of 300% or more and less than 800% and a breaking strength of 1.0 to 15 kg / cm ² in a tensile test at 23 ° C. The present invention relates to an adhesive sheet with a foamed base material, which has a pressure-sensitive adhesive layer on the base material.

In this specification, in the tensile test of the foamed elastomer at 23 ° C., a foamed elastomer sheet having a thickness of about 0.5 to 1.5 mm is punched out with a dumbbell No. 3 and a tensile tester is used. It was carried out under the conditions of a pulling speed of 500 mm / min.

[0009]

[Structure / Operation of the Invention] The foamed elastomer according to the present invention
Is kneaded with a rubber reinforcing agent, a vulcanizing agent, a foaming agent, a compounded composition that requires an anti-aging agent in an elastomer, and after molding this into a sheet shape, vulcanization and foaming are caused,
It is obtained.

Adhesive sheets with a foam base material have a wide variety of environmental conditions in which they are used, so that ozone resistance, ultraviolet resistance,
It is preferable that the durability is balanced in many items such as heat resistance, cold resistance, oil resistance, water resistance, acid resistance, and alkali resistance. From this point of view, as the elastomer, butyl rubber, chloroprene rubber, EPM (ethylene-propylene copolymer), EPDM (ethylene-propylene-dienter polymer), ethylene-acrylic ester copolymer, urethane rubber, epichlorohydrin rubber , Silicone rubber, hydrogenated nitrile rubber and the like are preferable, and epichlorohydrin type rubber is particularly preferable.

The epichlorohydrin rubber includes epichlorohydrin homopolymer, epichlorohydrin-ethylene oxide copolymer, epichlorohydrin-allyl glycidyl ether copolymer, epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer and the like. is there. From the viewpoint of ozone resistance and cold resistance, it is most preferable to use epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer.

Examples of the rubber reinforcing agent include inorganic reinforcing agents such as carbon black, white carbon (silica), basic magnesium carbonate, activated calcium carbonate, ultrafine pulverized magnesium silicate, and high styrene resin. , Cyclized rubber, coumarone indene resin, phenol
Organic reinforcing agents such as formaldehyde resin, modified melamine resin, vinyltoluene copolymer, lignin, phenol-formaldehyde resin fiber, and alicyclic petroleum resin are used.

As the vulcanizing agent, sulfur compounds such as sulfur, sulfur chloride, sulfur dichloride, morpholine disulphide, alkylphenol disulphide and the like, and inorganic vulcanizing agents such as selenium, tellurium, magnesium oxide, lisage, zinc white, etc. , P-quinonedioxime, p, p′-dibenzoylquinonedioxime, tetrachloro-p-benzoquinone,
Oximes such as poly-p-dinitrosobenzene, nitroso compounds, hexamethylenediamine, triethylenetetramine, tetraethylenepentamine, hexamethylenediaminecarbamate, N, N'-dicinnamiiden-
Polyamines such as 1,6-hexanediamine, 4,4'-methylenebis (cyclohexylamine) carbamate, 4,4'-methylenebis- (2-chloroaniline), dicumyl peroxide, t-butylcumyl peroxide, 2, 5-dimethyl-2,5-di (t-butylpar-
Oxy) hexyne-3,1,3-bis- (t-butylperoxypropyl) benzene, 1,1-bis- (t
-Butylperoxy) -3,3,5-trimethylcyclohexane, benzoylperoxide, organic peroxides such as tert-butylperoxyisopropyl carbonate, resin vulcanization such as alkylphenol sulfide resin, hexamethoxymethylmelamine resin Agents, polyfunctional (meth) acrylate monomers such as ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, etc., triallyl isocyanurate, 2, 4,
6-trimercapto-s-tridian, and the like,
From these, a suitable one may be selected according to the type of elastomer.

For the purpose of shortening the vulcanization time and lowering the vulcanization temperature, vulcanization accelerators such as guanidine series, aldehyde-amine series, aldehyde-ammonia series, dithiocarbamate series, and xanthate series are used. Among various compounds, suitable compounds may be used in combination depending on the kind of the vulcanizing agent. Further, zinc white, magnesium oxide and the like may be used together as the vulcanization accelerator together with the vulcanization accelerator.

Examples of the foaming agent include inorganic foaming agents such as sodium bicarbonate, ammonium bicarbonate and ammonium carbonate, nitroso compounds such as N, N'-dinitrosopentamethylenetetramine, benzenesulfonyl hydrazide and toluenesulfonyl hydrazide. Examples thereof include sulfonyl hydrazide compounds, and a suitable one may be selected according to the type of the vulcanizing agent. Further, for the purpose of lowering the foaming temperature, a known foaming aid suitable for the type of foaming agent may be used in combination.

As an antiaging agent, there are few blooms,
Those which do not inhibit the vulcanization reaction are preferable, and examples thereof include phenyl-naphthylamine, 4,4 ′-(α, α-dimethylbenzyl) diphenylamine, octylated diphenylamine, N-isopropyl-N′-phenyl-p-phenylenediamine, N-phenyl-N '-(3-methacryloyloxy-2-hydroxypropyl) -p-phenylenediamine, polymer of 2,2,4-trimethyl-1,2-dihydroquinoline, 2,5-di-t -Butylhydroquinone, 2,6-di-t-butyl-4-methylpheno-
4,4'-butylidene bis- (3-methyl-6-t
-Butylphenol), tris (nonylphenyl) phosphite and the like.

In addition to these essential components, anti-scorch agents, ultraviolet absorbers, mastication accelerators, processing aids, plasticizers, rubber softeners, fillers, stabilizers, which are usually compounded in rubber moldings, Various additives such as a lubricant, a flame retardant, an antistatic agent, a coloring agent and an antifungal agent may be added to the elastomer.

The kneading of the elastomer with these compounds is
The mixing may be carried out using equipment that usually kneads rubber compounds, such as a mixing grease, a Banbury mixer, a pressure kneader, a single-screw extruder, or a twin-screw extruder. The sheet forming may be performed by calender rolling or die extrusion. Vulcanization and foaming after sheet molding can be carried out by passing through an oven zone or a rotocurer.

Foamed elastomer obtained in this way
The sheet thickness is not particularly limited, but is generally preferably in the range of 0.5 to 5 mm. When it is less than 0.5 mm, the stress dispersibility is poor and the adherend selectivity is high. On the other hand, even if the thickness exceeds 5 mm, no remarkable improvement in characteristics is observed.

In the present invention, the tensile properties of such a foamed elastomer are as follows:
The breaking elongation and the apparent breaking strength are in the following ranges respectively: Breaking elongation: 300% or more and less than 800% (preferably 500)
To 700%) Breaking strength: 1.0 to 15 kg / cm ² (suitably 2.0 to 1)
It is characterized in that it is set to be 0 kg / cm ² ). That is, by having such a low modulus and a tensile physical property with a specific elongation, a foamed substrate-attached adhesive sheet using this as a substrate can express high adhesive strength to a member. .

On the other hand, in the tensile test at 23 ° C.,
If the breaking elongation is 800% or more, when used for fixing a fixing member such as a sticking suspender (hook), the load of the sheet causes the sheets to be greatly deformed, protruding from the hook and impairing the appearance. is there. On the other hand, if it is less than 300%, the amount of displacement is too small, stress concentration occurs at the adhesive interface, and peeling easily occurs. Further, if the apparent breaking strength is less than 1.0 kg / cm ² , it is too soft to be tensioned and there is a problem in the production process of the foamed sheet. On the other hand, if it exceeds 15 kg / cm ² , it is too stiff, and stress concentration also occurs at the adhesive interface, and it tends to peel off.

In order to set the tensile physical properties of the foamed elastomer within the range of the present invention described above, for example, the elastomer is
The method may be carried out by adjusting the type of the above-mentioned compound or the like, the number of compounded parts, etc., or controlling the cell size after foaming by vulcanization and foaming, etc., and these methods are not particularly limited.

The adhesive sheet with a foamed base material of the present invention has such a foamed elastomer as a base material and is provided with a layer of a pressure sensitive adhesive on one or both surfaces of the base material in a desired thickness. The shape is a sheet or tape.

The type of pressure-sensitive adhesive used here is not particularly limited, and may be rubber-based, acrylic-based, silicone-based or the like. Further, each of them may be a solution type or a non-solvent type such as an emulsion or a hot melt type. The thickness of the pressure-sensitive adhesive layer is also not particularly limited, and may be a thickness usually applied to adhesive sheets. When provided on both surfaces of the base material, the type, thickness, and various physical properties may be the same or different on the front and back.

As the method for providing the pressure-sensitive adhesive layer on the base material, a method of directly applying the pressure-sensitive adhesive on the base material, or a pressure-sensitive adhesive layer having a predetermined thickness on the separator is used. There is a method of forming and laminating it on a substrate. In these methods, the base material made of the foamed elastomer may be previously subjected to a primer treatment, a corona treatment, an electron beam treatment or the like for the purpose of improving the anchoring property of the adhesive layer.

The adhesive sheet with a foam base material of the present invention is used, for example, for fixing a mirror, a sticking suspender (hook), a nameplate, etc. to a wall or ceiling of a building, the surface of a mechanical device, etc. Alternatively, it can be widely used for fixing exterior members such as side molds and emblems to the body of an automobile, and also for various uses other than these.

[0027]

As described above, since the adhesive sheet with a foamed substrate of the present invention uses a foamed elastomer having a low modulus and a tensile property of appropriate elongation as a substrate, it is a fixing member. The external force applied to the is dispersed and relaxed by the foam layer, stress concentration on the adhesive interface is reduced, and the same level of high adhesive strength can be exhibited for various adherends.

[0028]

Next, examples of the present invention will be described in more detail with reference to reference examples. In the following,
Parts means parts by weight.

Reference Example 1 Using the epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer [Epichroma-CG manufactured by Daiso Co., Ltd.], the following compounding composition A was prepared and mixed. 0.6mm after kneading with a roll
And rolled to a sheet. Next, this sheet was heated at 160 ° C. for 10 minutes, vulcanized and foamed to obtain a foamed elastomer A having a thickness of 0.8 mm.

<Compounding Composition A> Epichroma CG 100 parts Calcium carbonate 30 parts Carbon black 30 parts Dioctyl phthalate 5 parts 2-Mercaptoimidazoline 0.7 parts Urea-based foaming aid 3 parts N, N'- Dinitrosopentamethylene tetramine 3 parts 2,2,4-trimethyl-1,2-dihydroquinoline polymer 3 parts Stearic acid 1 part

Reference Example 2 A foamed elastomer B having a thickness of 0.8 mm was obtained according to Reference Example 1 except that the following composition composition B was used in place of the composition composition A. In addition, in the following compounding composition B, the elastomer is an epichlorohydrin-ethylene oxide copolymer [Epichroma C manufactured by Daiso Co., Ltd.].
It was used.

<Composition B> Epichroma C 100 parts Calcium carbonate 30 parts Carbon black 20 parts 2-Mercaptoimidazoline 0.8 parts Urea-based foaming aid 3 parts N, N'-dinitrosopentamethylenetetramine 3 parts Polymer of 2,2,4-trimethyl-1,2-dihydroquinoline 3 parts Stearic acid 1 part

Reference Example 3 The following compounding composition C was prepared using butyl rubber 365 manufactured by Etsuso Co., Ltd.
It was rolled, further vulcanized and foamed to obtain 0.8 mm thick foamed elastomer C.

<Compounding composition C> Butyl rubber 365 100 parts Calcium carbonate 20 parts Carbon black 25 parts Paraffin oil [P-200 manufactured by Nippon Oil Co., Ltd.] 10 parts p-quinone dioxime 0.5 parts Zinc flower 5 parts N, N'-dinitrosopentamethylenetetramine 4 parts Urea-based foaming aid 4 parts 2,2,4-Trimethyl-1,2-dihydroquinoline polymer 3 parts Stearic acid 1 part

Reference Example 4 A foamed elastomer D having a thickness of 0.8 mm was obtained in the same manner as in Reference Example 1 except that the following compounding composition D was used in place of the compounding composition A.

<Compounding Composition D> Epichroma-CG 100 parts Calcium carbonate 30 parts Carbon black 30 parts Dioctyl phthalate 5 parts 2-Mercaptoimidazoline 2.5 parts Urea-based foaming aid 3 parts N, N'- Dinitrosopentamethylene tetramine 3 parts 2,2,4-trimethyl-1,2-dihydroquinoline polymer 3 parts Stearic acid 1 part

Reference Example 5 A foamed elastomer E having a thickness of 0.8 mm was obtained according to Reference Example 3 except that the following compounding composition E was used in place of the compounding composition C.

<Compounding composition E> Butyl rubber 365 100 parts Calcium carbonate 20 parts Carbon black 25 parts Paraffin oil [P-200 manufactured by Nippon Oil Co., Ltd.] 10 parts p-quinone dioxime 3 parts Zinc flower 5 parts N, N'-dinitrosopentamethylenetetramine 4 parts Urea foaming aid 4 parts 2,2,4-Trimethyl-1,2-dihydroquinoline polymer 3 parts Stearic acid 1 part

Foamed elastomer A of Reference Examples 1 to 5 above
-E is punched out with dumbbell No. 3 and 50 with a tensile tester
A tensile test was performed at 0 mm / min.
The breaking elongation (maximum elongation) and the breaking strength (strength at maximum elongation) were examined. These results were as shown in Table 1 below.

[0040]

[Table 1]

Example 1 Using the foamed elastomer A of Reference Example 1 as a base material, a sheet having a pressure-sensitive adhesive layer having a thickness of 100 μm prepared on both sides of the base material by the following method was laminated. Then, an adhesive tape with a foam substrate was prepared.

<Preparation of sheet having pressure-sensitive adhesive layer>
92 parts of 2-ethylhexyl acrylate, 8 of acrylic acid
Parts, N, N'-azobisisobutyronitrile, 0.2 part and ethyl acetate, 200 parts, were placed in a flask, purged with nitrogen, heated to 50 ° C., stirred for 20 hours, and polymerized. To the resulting polymer solution was added 1% by weight of a tolylene diisocyanate adduct of trimethylolpropane, applied to a release paper, dried at 130 ° C. for 5 minutes, and pressure-sensitively bonded to a thickness of 100 μm. A sheet having a layer of the agent was prepared.

Example 2 An adhesive tape with a foam substrate was prepared in exactly the same manner as in Example 1 except that the foam elastomer B of Reference Example 2 was used as the substrate.
Got

Example 3 An adhesive tape with a foam substrate was prepared in exactly the same manner as in Example 1 except that the foam elastomer C of Reference Example 3 was used as the substrate.
Got

Comparative Example 1 An adhesive tape with a foam substrate was prepared in the same manner as in Example 1 except that the foam elastomer D of Reference Example 4 was used as the substrate.
Got

Comparative Example 2 An adhesive tape with a foam substrate was prepared in exactly the same manner as in Example 1 except that the foam elastomer E of Reference Example 5 was used as the substrate.
Got

For each of the adhesive tapes with foamed base material of Examples 1 to 3 and Comparative Examples 1 and 2 described above, various adherends shown in Table 2 were used, and the adhesive strength was determined as follows. I took the test. The results are as shown in Table 2.

<Adhesive strength test> In an atmosphere of 23 ° C., Table 2
A 25 mm wide adhesive tape with a foam base material, one side of which is backed with a polyester film having a thickness of 50 μm, is one-way pressure-bonded with a 5 kg roller, and after 20 minutes, the adherend is subjected to 180 ° by a tensile tester. The peeling adhesive strength (peeling speed 50 mm / min) was measured. At this time, with the intermittent deformation of the foamed base material, the adhesive strength also increased and decreased intermittently. Therefore, the average value of 10 points on the maximum value side was used as the adhesive strength.

[0049]

[Table 2]

From the results of Table 2 above, Example 1 of the present invention
It is apparent that the adhesive tapes with a foamed base material of Nos. 3 to 3 cause a base material to be destroyed with respect to various adherends and exhibit extremely high adhesive strength at the same level.

Claims (2)

[Claims] 1. A tensile test at 23 ° C. has a breaking elongation of 300% or more and less than 800% and a breaking strength of 1.0 to.
An adhesive sheet with a foam base material, which comprises a base material of a foamed elastomer having a weight of 15 kg / cm ² and a layer of a pressure sensitive adhesive on the base material. 2. The adhesive sheet with a foamed base material according to claim 1, wherein the foamed elastomer contains epichlorohydrin rubber as a main component.