JP2010070655A - Foamed adhesive sheet and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a foamed adhesive sheet excellent in both the foaming uniformity and the tackiness, and to provide a method for efficiently manufacturing the same. <P>SOLUTION: In this method for manufacturing the foamed adhesive sheet 6, a composition which comprises 10-90 wt.% of a styrene-based thermoplastic elastomer (A), 90-10 wt.% of a tackifier (B) (the sum of component (A) and component (B) is set to 100 wt.%), and 1-5 pts.wt. of a heat-expandable microcapsule-type foaming agent (C) based on 100 pts.wt. of the sum of component (A) and component (B) is expansion-molded at 170-250°C with an extruder 1 having a T-die 2. A method for manufacturing a laminated adhesive sheet 7 includes laminating the foamed adhesive sheet 6 and a substrate 5 with a press roll 3 and a cooling roll 4. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a foamed pressure-sensitive adhesive sheet having excellent foaming uniformity and adhesiveness. More specifically, the present invention relates to a foamed pressure-sensitive adhesive sheet obtained by extrusion-molding a resin composition containing a styrenic thermoplastic elastomer and a tackifier containing a foaming agent into a sheet by a T-die extruder, and a method for producing the same.

  By making the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape and pressure-sensitive adhesive sheet into a fine foam structure, efforts have been made to lower the apparent elastic modulus, improve the pressure-sensitive adhesive properties, and reduce material costs by reducing the amount of pressure-sensitive adhesive used. ing. A laminated adhesive dustproof cleaner in which such a foamed adhesive layer is closely formed on a substrate is also known (see, for example, Patent Documents 1 and 2).

  By the way, in the production of conventional foamed adhesive tape and adhesive sheet, it is common to use a solvent such as diluting the adhesive composition with a solvent and applying it to a support. Development of production methods that are not used is underway. For example, a method is disclosed in which an existing pressure-sensitive adhesive sheet is dissolved in a pressure-sensitive adhesive layer under an inert gas atmosphere at a high pressure, and then the pressure-sensitive adhesive layer is foamed by releasing the pressure (patent) Reference 3). However, this method is disadvantageous from the viewpoint of continuous production because the process is complicated and high pressure inert gas is used. Also, there is provided a foamed pressure-sensitive adhesive sheet comprising a step of kneading a pressure-sensitive adhesive composition containing a polymer constituting a pressure-sensitive adhesive layer and a crosslinking agent for crosslinking the polymer in the pressure-sensitive adhesive composition together with a supercritical state or an inert fluid under pressure. A manufacturing method is known (see Patent Document 4). However, even in this method, it is necessary to use a crosslinking agent that crosslinks the polymer in the pressure-sensitive adhesive composition, and to use a rare gas or an inorganic gas in a supercritical state or a liquid state under pressure.

  In addition, as the polymer for forming the pressure-sensitive adhesive layer, an acrylic acid compound having an isocyanate group-reactive functional group (see Patent Document 1) and an acrylic ester copolymer (see Patent Document 4) are used. No method has been put to practical use in which a thermoplastic elastomer is used as a raw material and foaming is performed simultaneously with a T-die extruder without using a solvent and a sheet is obtained.

Japanese Patent Laid-Open No. 7-165964 JP-A-7-157588 JP 2000-169803 A JP 2006-36870 A

  Under such circumstances, an object of the present invention is to provide a foamed pressure-sensitive adhesive sheet having excellent foaming uniformity and adhesiveness. Furthermore, the present invention provides a foamed pressure-sensitive adhesive sheet obtained by foam-molding a resin composition containing a specific foaming agent, a styrenic thermoplastic elastomer and a tackifier by a T-die extruder, and an efficient production method thereof. It is.

  As a result of various studies to solve the above problems, the inventor of the present application uses a thermally expandable microcapsule type foaming agent in a state where the resin molding temperature in a T-die extruder is controlled, and a styrene-based thermoplastic elastomer. It was found that a pressure-sensitive adhesive foam sheet having excellent foaming uniformity and adhesiveness can be obtained by combining a tackifier and a tackifier, and the present invention has been completed. That is, the present invention relates to the following inventions (1) to (10).

(1) Styrenic thermoplastic elastomer (A), tackifier (B), and thermally expandable microcapsule type foaming agent (C) are included, and styrene thermoplastic elastomer (A) is 10 to 90% by weight. , 90 to 10% by weight of the tackifier (B) (provided that the total of the component (A) and the component (B) is 100% by weight), and the component (A) and the component (B) A foamed pressure-sensitive adhesive sheet obtained by foam-molding a composition having 1 to 5 parts by weight of a heat-expandable microcapsule type foaming agent (C) at 170 to 250 ° C. with respect to a total of 100 parts by weight.

(2) The thermally expandable microcapsule-type foaming agent (C) is a microsphere having an average particle diameter of 10 to 40 μm having a double structure in which a liquefied low-boiling hydrocarbon is encapsulated using a thermoplastic resin as a shell wall ( 1) The foamed pressure-sensitive adhesive sheet as described.

(3) The foamed adhesive sheet according to (1) or (2), wherein the foamed adhesive sheet has a thickness of 100 to 300 μm.

(4) Styrenic thermoplastic elastomer (A), tackifier (B), and thermally expandable microcapsule type foaming agent (C) are included, and styrene thermoplastic elastomer (A) is 10 to 90% by weight. , 90 to 10% by weight of the tackifier (B) (provided that the total of the component (A) and the component (B) is 100% by weight), and the component (A) and the component (B) A foamed adhesive resin obtained by foaming a composition having 1 to 5 parts by weight of a thermally expandable microcapsule type foaming agent (C) with a T-die extruder at 170 to 250 ° C. with respect to a total of 100 parts by weight is laminated on a base material A laminated adhesive sheet.

(5) The thermally expandable microcapsule-type foaming agent (C) is a microsphere having a double-structured average particle diameter of 10 to 40 μm and containing a liquefied low-boiling hydrocarbon with a thermoplastic resin as a shell wall ( 4) Laminated adhesive sheet.

(6) The laminated pressure-sensitive adhesive sheet according to (4) or (5), wherein the thickness of the laminated pressure-sensitive adhesive sheet is 120 to 350 μm.

(7) Styrenic thermoplastic elastomer (A), tackifier (B), and thermally expandable microcapsule type foaming agent (C) are included, and styrene thermoplastic elastomer (A) is 10 to 90% by weight. , 90 to 10% by weight of the tackifier (B) (provided that the total of the component (A) and the component (B) is 100% by weight), and the component (A) and the component (B) A method for producing a foamed pressure-sensitive adhesive sheet, comprising foam-molding a composition having 1 to 5 parts by weight of a heat-expandable microcapsule type foaming agent (C) at 170 to 250 ° C. with respect to a total of 100 parts by weight.

(8) Styrenic thermoplastic elastomer (A), tackifier (B) and thermally expandable microcapsule type foaming agent (C) are included, and styrene thermoplastic elastomer (A) is 10 to 90% by weight. , 90 to 10% by weight of the tackifier (B) (provided that the total of the component (A) and the component (B) is 100% by weight), and the component (A) and the component (B) Lamination which laminates a foaming adhesive resin foamed at 170-250 ° C. by a T-die extruder with a composition having 1-5 parts by weight of thermally expandable microcapsule type foaming agent (C) with respect to 100 parts by weight in total on a base material A method for producing an adhesive sheet.

(9) An adhesive dustproof tape comprising the foamed adhesive sheet according to any one of (1) to (3) as an adhesive layer.

(10) An adhesive dustproof tape comprising the laminated adhesive sheet according to any one of (4) to (6).

  The foamed adhesive sheet of the present invention is excellent in foaming uniformity, and has sufficient adhesiveness and chemical stability. Furthermore, the foamed pressure-sensitive adhesive sheet of the present invention can be easily formed into a foamed sheet by a T-die extruder and has very high productivity. Thus, since the foamed adhesive sheet of the present invention is excellent in adhesiveness and does not use a solvent (solvent-free), it is particularly suitably used as an adhesive dustproof tape or sheet for clean rooms.

Hereinafter, the present invention will be described in detail.
This invention contains each component of a styrene-type thermoplastic elastomer (A), a tackifier (B), and a thermally expansible microcapsule type foaming agent (C), and a styrene-type thermoplastic elastomer (A) is 10 to 90 weight. %, Pressure-sensitive adhesive imparting agent (B) is 90 to 10% by weight (provided that the total of component (A) and component (B) is 100% by weight), and component (A) and component (B) A foamed adhesive sheet obtained by foam-molding a composition having 1 to 5 parts by weight of a heat-expandable microcapsule type foaming agent (C) at 170 to 250 ° C. with respect to 100 parts by weight It is. Here, the styrenic thermoplastic elastomer (A) used in the present invention refers to a vinyl aromatic compound-conjugated diene copolymer or a hydrogenated product thereof.

  As the vinyl aromatic compound, for example, a vinyl aromatic compound having 8 to 12 carbon atoms is used, and the 1- or 2-position of the vinyl group may be substituted with an alkyl group such as a methyl group. Specifically, styrene, p-methylstyrene, α-methylstyrene and the like can be mentioned, and these are used alone or in combination of two or more.

  As the conjugated diene, for example, a conjugated diene having 4 to 8 carbon atoms is used, and butadiene, 2-methyl-1,3-butadiene (isoprene), pentadiene, 2,3-dimethyl-1,3-butadiene and the like are used. These may be used alone or in combination of two or more.

  Examples of the vinyl aromatic compound-conjugated diene copolymer include a copolymer of styrene and butadiene, a copolymer of styrene and isoprene, and the like.

  Specific examples include a styrene-butadiene copolymer, a styrene-isoprene copolymer, a styrene-butadiene-styrene copolymer, and a styrene-isoprene-styrene copolymer. In such a copolymer, each monomer of styrene, butadiene, and isoprene may have a structure in which they are copolymerized randomly, or may have a block structure in which each monomer is homopolymerized. Examples of these include styrene block-butadiene block copolymers and styrene block-styrene / butadiene block copolymers.

  Further, the hydrogenated vinyl aromatic compound-conjugated diene copolymer is a polymer obtained by hydrogenating the above-mentioned vinyl aromatic compound-conjugated diene copolymer. These are used alone or in combination of two or more.

  Specific examples of the styrenic thermoplastic elastomer (A) used in the present invention include styrene block-butadiene block styrene block copolymer (SBS), styrene block-isoprene block-styrene block copolymer (SIS), and Or partially or completely hydrogenated (generally referred to as SEBS and SEPS, respectively). Depending on the application of the pressure-sensitive adhesive sheet, a styrene block-butadiene block copolymer, a styrene block-styrene / butadiene block copolymer, or a partial or complete hydrogenated product thereof is preferably used.

  Commercially available products of the above copolymers include styrene block-butadiene block styrene block copolymer hydrogenated products and styrene block-isoprene block-styrene block copolymer hydrogenated products, such as “Clayton-G” (Clayton Polymer Japan). Co., Ltd .: trade name), “Tuftec” (Asahi Kasei Co., Ltd .: trade name), “Septon” (Kuraray Co., Ltd .: trade name), and hydrogenated styrene block-styrene / butadiene block copolymer Examples of such products include “Tuftec S.O.E” (Asahi Kasei Corporation: trade name).

  The melt flow rate (MFR) measured at 230 ° C. under a load of 21.18 N according to JIS K-7210 of a styrene-based thermoplastic elastomer is preferably 1 to 200 g / 10 minutes from the viewpoint of further improving the meltability at the time of molding. More preferably, it is 3 to 100 g / 10 minutes.

  Next, as the tackifier used in the present invention, rosin resin, terpene phenol resin, terpene resin, non-aromatic hydrocarbon modified terpene resin, petroleum resin, and the like are used. The softening point of these resins is preferably 120 ° C. or lower, more preferably 110 ° C. or lower. The tackifier is preferably used as a masterbatch pre-blended with a styrenic thermoplastic elastomer. The amount of tackifier in the masterbatch is generally 10 to 70% by weight. Moreover, it is desirable to add suitably the liquid elastomer mentioned later to a masterbatch for adhesiveness provision or a softness | flexibility provision. Examples of such a tackifier include hydrogenated petroleum resin “Alcon P-100” (Arakawa Chemical Industries, Ltd., trade name), disproportionated rosin ester “Super Ester A-100” (Arakawa Chemical Industries, Ltd., commodity) Name), terpene phenol resin “YS Polystar T-115” (Yasuhara Chemical Co., Ltd., trade name).

  In addition, it is also possible to use a styrene thermoplastic elastomer containing a tackifier in advance as the styrene thermoplastic elastomer. Proper (Sekisui Fuller Co., Ltd .: trade name) is an example of such a resin. In this case, it is more preferable to combine with other styrenic thermoplastic elastomers in order to adjust the physical properties (viscosity, elasticity, etc.) of the final product. As the styrene-based thermoplastic elastomer to be combined, the above-mentioned styrene-based thermoplastic elastomer is appropriately used. Among them, “Tuftec S.O.E”, which is a hydrogenated product of a styrene block-styrene / butadiene block copolymer, is preferable. Used for. On the other hand, in the case of a combination with a polyolefin other than the styrenic thermoplastic elastomer, a sheet with good adhesiveness cannot be obtained for unknown reasons.

  As the thermally expandable microcapsule type foaming agent (C) of the present invention, both a temperature at which the composition containing the styrenic thermoplastic elastomer of the present invention and a viscosity-imparting agent are subjected to T-die extrusion molding and a closed cell foamed sheet are obtained. Selected from the point of view. In the present invention, a thermally expandable microcapsule type foaming agent containing carbon dioxide and low-boiling hydrocarbons that can be used at 170 to 250 ° C., preferably 180 to 230 ° C., is suitably used.

  Among the thermally expandable microcapsule-type foaming agents (C), a double-structured thermally-expandable microcapsule-type foaming agent that includes a thermoplastic resin as a shell wall and encapsulates liquefied low-boiling hydrocarbons is preferably used. . The microcapsule is a thermoplastic resinous microsphere having an average particle size of 10 to 40 μm (particularly preferably 15 to 30 μm). As the thermoplastic resin as the shell wall, the above-mentioned thermoplastic resins can be used. Among them, homopolymers of ethylene and propylene and copolymers thereof can be preferably used. In particular, low density polyethylene having good flowability can be suitably used. This thermally expandable microcapsule type foaming agent is usually used as a master batch with a thermoplastic resin. Specifically, the Fine Cell Master MS series (Daiichi Seika Kogyo Co., Ltd.) can be mentioned. A foaming aid may be added to these foaming agents as appropriate in order to adjust the decomposition temperature.

  In the present invention, the composition containing each component of the styrene-based thermoplastic elastomer (A), the tackifier (B), and the thermally expandable microcapsule-type foaming agent (C) has a styrene-based thermoplastic elastomer (A) of 10 to 10%. 90% by weight, 10% to 90% by weight of the tackifier (B) (provided that the total of the component (A) and the component (B) is 100% by weight), and the component (A) and the component ( The heat-expandable microcapsule type foaming agent (C) is 1 to 5 parts by weight based on 100 parts by weight of the total of B). The ratio between the styrene-based thermoplastic elastomer (A) and the adhesive-imparting agent (B) is appropriately determined depending on the intended foamed sheet. For example, in the use of an adhesive dustproof tape or sheet, from the viewpoint of adhesiveness and uniform foaming. The ratio of the hot styrenic thermoplastic elastomer (A) and the tackifier (B) can be suitably used in the range of 20 to 40% by weight / 60 to 80% by weight.

  On the other hand, the foaming agent (C) is 1 to 5 parts by weight, preferably 2 to 4 parts by weight, based on the total of 100 parts by weight of the component (A) and the component (B) as described above. If it is less than this, uniform foaming cannot be obtained, and if it exceeds this, foaming efficiency is not improved.

To the resin composition of the present invention, a liquid elastomer such as paraffinic, naphthenic, aromatic mineral or petroleum hydrocarbons, polybutene or polyisobutylene is added to impart tackiness or flexibility. Is desirable. These usually have a weight average molecular weight of 300 to 2000, preferably 500 to 1500. For example, Diana process oil PW90 (Idemitsu Kosan Co., Ltd.) can be used as the paraffinic oil.
These addition amounts are 10 to 200 parts by weight based on the total of 100 parts by weight of component (A) and component (B).

  Further, the resin composition of the present invention may further be appropriately added with a material for preventing resin deterioration such as an antioxidant and an ultraviolet absorber, an antistatic material, and the like.

The resin composition of the present invention is foam-molded using a T-die extruder to form a sheet or a tape. In the present invention, the term “sheet” is a concept including a film of μm order.
The foaming temperature of the T-die extruder is appropriately determined depending on the composition of the resin composition to be used, but it is important to keep it at 170 to 250 ° C, preferably 170 to 230 ° C, more preferably 180 to 220 ° C. is there.
That is, in order that the sheet foam-molded from the resin composition of the present invention has independent foaming properties and can be obtained efficiently with a T-die extruder, it is necessary to control the foam molding temperature within the above range. is there. If the foaming temperature is lower than 170 ° C, uneven foaming occurs and a uniform independent foamed sheet cannot be obtained. On the other hand, if the foaming temperature is higher than 250 ° C, the product deteriorates and the foaming property becomes uneven. The problem arises.

The foamed pressure-sensitive adhesive sheet obtained by the present invention is a pressure-sensitive adhesive foamed sheet containing a styrenic thermoplastic elastomer having a closed cell property and a tackifier, and since bubbles by the foaming agent are included therein, it is lightweight and sticky. And has the characteristics of being solvent-free.
The thickness of the foamed sheet is appropriately determined depending on the use and can be molded from several tens of μm to several tens of mm. However, the thickness of the resin foamed sheet suitable as an adhesion control cleaner is 100 to 300 μm, particularly preferably 150. ˜250 μm.
Usually, the expansion ratio is 1.1 to 5 times. The sheet can also be a multilayer foam sheet by multilayer coextrusion.

  The resin foam sheet obtained by the present invention can be suitably used as a laminated pressure-sensitive adhesive sheet laminated with a substrate. Examples of the base material include metals such as aluminum and iron, thermoplastic resins, paper, synthetic paper, thin plate materials made of glass wool, nonwoven fabrics, woven fabrics, and the like. A polypropylene stretched film (sheet) is preferably used as an adhesive dustproof tape and sheet base material to be described later. The thickness of the substrate is 10 to 100 μm, preferably 20 to 50 μm. As the thickness of the laminated pressure-sensitive adhesive sheet, a thickness of 120 to 350 μm is preferably used. Lamination of the resin foam sheet to the substrate can be efficiently carried out by directly laminating the foamed adhesive resin (sheet) extruded from the T-die onto the substrate.

Next, an adhesive dustproof tape using the foamed adhesive sheet of the present invention will be described.
In general, an adhesive dustproof tape has an adhesive layer formed on one side of a base material, and a release treatment layer or a release film (sheet) is laminated on the opposite side of the base material. Moreover, you may provide an antistatic agent layer between base materials.
As the base material, a plastic film is generally used, and an oriented polypropylene film (OPP) or a nonwoven fabric is preferably used. For the release treatment layer, a release agent such as a non-silicone-based fluorine resin, a polyolefin resin, or an acrylic resin is used from the viewpoint of preventing corrosion and malfunction of the electronic component. The release treatment layer can be provided by extruding a release material from a T die and laminating it on a base material. A sheet such as a polyester film is used as the release sheet. In addition, a peeling process layer and a peeling sheet are not essential, and are installed or used as needed.

The present invention will be briefly described with reference to FIG. A composition containing a styrenic thermoplastic elastomer, a tackifier and a thermally expandable microcapsule type foaming agent is melt-kneaded in the extruder (1), and the foamed resin is extruded from the T-die (2) and supplied separately. The foamed adhesive resin (6) is laminated on the base material (OPP) (5). And a laminated adhesive sheet (7) is formed by laminating | stacking the peeling sheet (PET film) (not shown) supplied separately as needed. This laminated adhesive sheet is suitably used as an adhesive dustproof tape.
In general, the above adhesive dustproof tape is used in the form of a roll wound around the core material with the surface on the adhesive layer side facing outside. What is necessary is just to select the form suitably according to use purposes, such as a sheet-like form, without turning.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples.

[Adhesion test method]
The adhesive strength of the foamed adhesive sheet was measured in accordance with JIS Z0237, and the test piece was peeled off by 180 degrees under the following conditions.
Test conditions:
Tensile speed 300mm / min
Chuck interval 150mm
Specimen width 25mm x length 250mm
Test plate SUS 304 steel plate (mirror finish) Thickness 2mm x Width 50mm x Length 125mm
In addition, after sticking a test piece on a test plate, it left still for 5 minutes and measured.

Example 1
50% by weight of “Tuftec H1221” (SEBS: Asahi Kasei Co., Ltd.) as the styrenic thermoplastic elastomer (A), and 50% by weight of hydrogenated petroleum resin “Alcon P-100” (Arakawa Chemical Industries) as the tackifier (B) %, A fine cell master MS401 (manufactured by Dainichi Seika Kogyo Co., Ltd.) as a thermally expandable microcapsule foaming agent (C) with respect to 100 parts by weight of the total of the styrene thermoplastic elastomer (A) and the tackifier (B). T-die extruder (model number: 1432, cylinder diameter: 115 mm, screw length, manufactured by Johoku Seisakusho Co., Ltd.), in which a resin composition blended with 2 parts by weight of a maximum foaming temperature: about 175 ° C. / Diameter ratio (L / D): 29)), and the resin composition was heated and melted in an extruder to perform foaming. The foamed molten resin is extruded from the lip portion into a sheet by a T-die set at a temperature of 175 ° C., and foamed on a separately supplied 1100 mm wide and 40 μm thick expanded polypropylene (OPP) film (manufactured by Toyobo Co., Ltd.). An adhesive sheet was laminated. Then, the laminated pressure-sensitive adhesive sheet 1 was obtained by being sandwiched and brought into contact with the cooling surface of the cooling roll and cooling to 15 ° C. The thickness of the obtained laminated pressure-sensitive adhesive sheet 1 was about 200 μm (about 160 μm as a foamed pressure-sensitive adhesive sheet), and it was confirmed that the whole foamed pressure-sensitive adhesive sheet was uniformly foamed. The foamed pressure-sensitive adhesive sheet was sticky, and peeled off by 180 degrees. The adhesive strength was 500 g / mm at the center of the sheet.

Example 2
Proper 6288 (Sekisui Fuller Co., Ltd .: trade name) is used as a styrenic thermoplastic elastomer in which the tackifier (B) is previously contained in the styrenic thermoplastic elastomer (A), and for 100 parts by weight of Propel 6288, Cylinder temperature is set in advance for a resin composition blended with 2 parts by weight of Fine Cell Master MS (manufactured by Dainichi Seika Kogyo Co., Ltd., maximum foaming temperature: about 230 ° C) as a thermally expandable microcapsule foaming agent (C) The T-die extruder (Johoku Seisakusho Co., Ltd. (model number: 1432, cylinder diameter: 115 mm, screw length / diameter ratio (L / D): 29)) is put into the hopper and the resin composition is heated in the extruder. It melted and foamed. The foamed molten resin is extruded in a sheet form from the lip portion with a T-die set at a temperature of 215 ° C., and foamed on a separately supplied 1100 mm wide and 40 μm thick expanded polypropylene (OPP) film (manufactured by Toyobo Co., Ltd.). An adhesive sheet was laminated. Thereafter, the laminated pressure-sensitive adhesive sheet 2 was obtained by being sandwiched and brought into contact with the cooling surface of the cooling roll and cooling to 15 ° C. The thickness of the obtained laminated pressure-sensitive adhesive sheet 2 was about 240 μm (about 200 μm as a foamed pressure-sensitive adhesive sheet), and it was confirmed that the entire foamed pressure-sensitive adhesive sheet was uniformly foamed. It was confirmed that the foamed pressure-sensitive adhesive sheet is sticky.

Example 3
In Example 2, 65% by weight of Propel 6288 as a styrenic thermoplastic elastomer and Tuftec S.I. O. E “SS9000” (manufactured by Asahi Kasei Co., Ltd.) was used in an amount of 35% by weight, and 2 parts by weight of Fine Cell Master MS was used as the thermally expandable microcapsule type foaming agent (C). The laminated adhesive sheet 3 was obtained. The thickness of the obtained laminated adhesive sheet 3 was about 250 μm (about 210 μm as a foamed adhesive sheet), and it was confirmed that the entire foamed adhesive sheet was uniformly foamed. When the cross section of the foamed adhesive sheet was observed with a digital microscope (Keyence Corporation, model number VHX-900), many closed cells having a diameter of several tens of μm were confirmed (FIG. 2). The foamed pressure-sensitive adhesive sheet was sticky and peeled off by 180 degrees, and the adhesive strength was 453 g / mm at the center of the sheet. This adhesive strength is suitable for an adhesive dustproof tape (sheet).

Example 4
In Example 3, 75% by weight of Propel 6288 as a styrenic thermoplastic elastomer and Tuftec S.I. O. E “SS9000” (manufactured by Asahi Kasei Co., Ltd.) was used in an amount of 25% by weight, and the same procedure as in Example 3 except that 3 parts by weight of Fine Cell Master MS was used as the thermally expandable microcapsule foaming agent (C). The laminated adhesive sheet 4 was obtained. The thickness of the obtained laminated pressure-sensitive adhesive sheet 4 was about 300 μm (about 260 μm as a foamed pressure-sensitive adhesive sheet), and it was confirmed that the whole foamed pressure-sensitive adhesive sheet was uniformly foamed. It was confirmed that the foamed pressure-sensitive adhesive sheet is sticky.

Reference example 1
In Example 3, 70% by weight of Propel 6288 as a styrenic thermoplastic elastomer and Tuftec S.I. O. A laminated sheet was obtained in the same manner as in Example 3 except that 30% by weight of polypropylene (product name: PHA03A) was used instead of E “SS9000”. The foamed sheet portion of the laminated sheet was foamed but did not have adhesiveness.

Reference example 2
In Example 3, 70% by weight of Propel 6288 as a styrenic thermoplastic elastomer, O. A laminated sheet was obtained in the same manner as in Example 3 except that 30% by weight of EVA (product name; Ultrasen 633; VA content 20% by weight) was used instead of E “SS9000”. The foamed sheet portion of the laminated sheet was foamed but did not have tackiness.

Comparative Example 1
Cell foam (manufactured by Sankyo Kasei Co., Ltd., trade name: cell microphone, product number: MB-5064) was used as a foaming agent instead of Fine Cell Master MS (manufactured by Dainichi Seika Kogyo Co., Ltd., maximum foaming temperature: about 230 ° C.). Except for the above, a laminated pressure-sensitive adhesive sheet was obtained in the same manner as in Example 2. Although the foamed adhesive sheet was foamed, it was non-uniform continuous foaming, and there were almost no independent bubbles. Further, the sheet was yellowed and had no commercial value.

  The foamed pressure-sensitive adhesive sheet of the present invention is excellent in foaming uniformity and has sufficient tackiness and chemical stability. Further, the foamed pressure-sensitive adhesive sheet is solvent-free, and is particularly preferably used as an adhesive dustproof tape or sheet. Furthermore, the composition of the present invention can be easily formed into a foam sheet or a laminated sheet with a T-die extruder and has very high productivity.

It is the schematic showing the manufacture flow of the lamination adhesive sheet of this invention. It is a digital microscope image of the foaming adhesive sheet of Example 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Extruder 2 T die 3 Press roll 4 Cooling roll 5 Base material 6 Foaming adhesive resin (foaming adhesive sheet)
7 Laminated adhesive sheet

Claims (10)

  10 to 90% by weight of styrene-based thermoplastic elastomer (A), each component of styrene-based thermoplastic elastomer (A), tackifier (B) and thermally expandable microcapsule-type foaming agent (C) The imparting agent (B) is 90 to 10% by weight (provided that the total of the component (A) and the component (B) is 100% by weight), and the total of the component (A) and the component (B) is 100% by weight. A foamed pressure-sensitive adhesive sheet obtained by foam-molding a composition having 1 to 5 parts by weight of a heat-expandable microcapsule-type foaming agent (C) with a T-die extruder at 170 to 250 ° C.   The heat-expandable microcapsule-type foaming agent (C) is a microsphere having an average particle diameter of 10 to 40 μm having a double structure in which a thermoplastic resin is used as a shell wall and liquefied low-boiling hydrocarbons are included. The foamed pressure-sensitive adhesive sheet according to claim 1.   The foamed adhesive sheet according to claim 1 or 2, wherein the foamed adhesive sheet has a thickness of 100 to 300 µm.   10 to 90% by weight of styrene-based thermoplastic elastomer (A), each component of styrene-based thermoplastic elastomer (A), tackifier (B) and thermally expandable microcapsule-type foaming agent (C) The imparting agent (B) is 90 to 10% by weight (provided that the total of the component (A) and the component (B) is 100% by weight), and the total of the component (A) and the component (B) is 100% by weight. A foamed adhesive resin obtained by foaming a composition having 1 to 5 parts by weight of a heat-expandable microcapsule-type foaming agent (C) with a T-die extruder at 170 to 250 ° C. is laminated on a substrate. A laminated pressure-sensitive adhesive sheet characterized by that.   The heat-expandable microcapsule-type foaming agent (C) is a microsphere having an average particle diameter of 10 to 40 μm having a double structure in which a thermoplastic resin is used as a shell wall and liquefied low-boiling hydrocarbons are included. The laminated pressure-sensitive adhesive sheet according to claim 4.   The laminated adhesive sheet according to claim 4 or 5, wherein the thickness of the laminated adhesive sheet is 120 to 350 µm.   10 to 90% by weight of styrene-based thermoplastic elastomer (A), each component of styrene-based thermoplastic elastomer (A), tackifier (B) and thermally expandable microcapsule-type foaming agent (C) The imparting agent (B) is 90 to 10% by weight (provided that the total of the component (A) and the component (B) is 100% by weight), and the total of the component (A) and the component (B) is 100% by weight. A method for producing a foamed pressure-sensitive adhesive sheet, comprising foam-molding a composition having 1 to 5 parts by weight of a thermally expandable microcapsule-type foaming agent (C) with a T-die extruder at 170 to 250 ° C.   10 to 90% by weight of styrene-based thermoplastic elastomer (A), each component of styrene-based thermoplastic elastomer (A), tackifier (B) and thermally expandable microcapsule-type foaming agent (C) The imparting agent (B) is 90 to 10% by weight (provided that the total of the component (A) and the component (B) is 100% by weight), and the total of the component (A) and the component (B) is 100% by weight. A composition comprising 1 to 5 parts by weight of a heat-expandable microcapsule type foaming agent (C) relative to a part is laminated on a base material with a foamed adhesive resin foamed at 170 to 250 ° C. by a T-die extruder. A method for producing a laminated adhesive sheet.   An adhesive dustproof tape comprising the foamed adhesive sheet according to any one of claims 1 to 3 as an adhesive layer.   An adhesive dustproof tape comprising the laminated adhesive sheet according to any one of claims 4 to 6.