JPWO2019066060A1 - Adhesive composition and adhesive tape - Google Patents

Abstract

The pressure-sensitive adhesive composition of the present invention has 100 parts by mass of an acrylic polymer (X) having a weight average molecular weight of 550,000 to 1,000,000 and 3 to 9 parts by mass of a tackifier resin (Y) having a softening point of 140 to 160 ° C. A pressure-sensitive adhesive composition containing a part and a cross-linking agent (Z). The acrylic polymer (X) contains 60% by mass or more of the (meth) acrylic acid alkyl ester monomer (a) having 4 or less carbon atoms in the alkyl group, and 100 parts by mass of the (meth) acrylic acid alkyl ester monomer (A). It is a polymer of a monomer component containing 5 to 18 parts by mass of a carboxyl group-containing monomer (B). According to the present invention, an adhesive composition having high adhesive strength to a difficult-to-adhere object such as polypropylene resin and suppressing a decrease in adhesive strength with time to a soft polyvinyl chloride resin, and the adhesive An adhesive tape using the agent composition can be provided.

Description

The present invention relates to a pressure-sensitive adhesive composition and a pressure-sensitive adhesive tape using the pressure-sensitive adhesive composition. More specifically, for example, a pressure-sensitive adhesive composition in which a soft polyvinyl chloride resin is to be adhered and a base material containing a plasticizer is used as a base material for an adhesive tape, and the pressure-sensitive adhesive composition are used. Regarding the adhesive tape that was there.

Adhesive tapes are widely used for curing, packing, repairing, etc. because of their excellent workability. For example, an adhesive tape having an acrylic adhesive layer is excellent in various physical properties such as weather resistance, durability, heat resistance, and transparency, so that a member can be fixed inside a vehicle, a house, an electronic device, or the like. Widely used.
As the adhesive tape, a base material and a tape having an adhesive layer provided on at least one surface of the base material are often used, and the material constituting the pressure-sensitive adhesive layer affects the adhesive force to the adherend. Therefore, it is necessary to design according to the material type of the adherend. Patent Document 1 solves a problem of a decrease in adhesive strength over time due to migration of a plasticizer when an adhesive tape having an acrylic pressure-sensitive adhesive layer is used for a soft polyvinyl chloride resin. A technique for using a pressure-sensitive adhesive composition in which a specific acrylic copolymer and a metal chelate cross-linking agent are blended is disclosed.

Japanese Unexamined Patent Publication No. 2006-199843

By the way, in recent years, members, sheets and the like made of soft polyvinyl chloride resin as raw materials are often used as interior materials of vehicles, and an adhesive tape for such interior materials is required. Therefore, it is required to more highly prevent the problem of decrease in adhesive strength due to the migration of the plasticizer in the above-mentioned soft polyvinyl chloride resin.
In addition, adhesive tapes generally have low adhesive strength to adherends such as polypropylene resin having low polarity, which are widely used as vehicle members, and have high adhesive strength even to such difficult-adhesive bodies. It is required. As a method for improving the adhesive strength to such a difficult-to-adhere body, a technique is known in which a certain amount of the tackifier resin is contained in the pressure-sensitive adhesive layer. However, when the tackifier resin is contained, the tackifier resin is contained. However, the above-mentioned migration of the plasticizer is promoted, which causes a problem of a decrease in adhesive strength with time to the soft polyvinyl chloride resin. Therefore, there is a demand for an adhesive tape having an adhesive layer having an improved adhesiveness to a poorly adherent body such as polypropylene resin while suppressing a decrease in adhesive strength with time to a soft polyvinyl chloride resin.
In some cases, a porous body containing a thermoplastic resin and a plasticizer is used as a base material, and an adhesive tape capable of suppressing a decrease in adhesive strength due to the transfer of the plasticizer to such a base material is available. It has been demanded.

The present invention has been made in view of the above-mentioned conventional problems, and is a pressure-sensitive adhesive composition containing a certain amount of a tackifier resin, which suppresses a decrease in adhesive strength with time, and a pressure-sensitive adhesive composition thereof. The purpose is to develop an adhesive tape using.

The present inventors have conducted intensive studies to achieve the above object. As a result, a pressure-sensitive adhesive composition containing an acrylic polymer which is a polymer of a specific (meth) acrylic acid alkyl ester monomer and a specific amount of a carboxyl group-containing monomer, a specific pressure-imparting resin, and a cross-linking agent. , And an adhesive tape using the pressure-sensitive adhesive composition can solve the above-mentioned problems, and completed the present invention.
That is, the present invention relates to the following [1] to [18].
[1] 100 parts by mass of the acrylic polymer (X) having a weight average molecular weight of 550,000 to 1,000,000, 3 to 9 parts by mass of the tackifier resin (Y) having a softening point of 140 to 160 ° C., and a cross-linking agent ( A pressure-sensitive adhesive composition containing Z).
The acrylic polymer (X) contains 60% by mass or more of the (meth) acrylic acid alkyl ester monomer (a) having 4 or less carbon atoms in the alkyl group, and 100 parts by mass of the (meth) acrylic acid alkyl ester monomer (A). A pressure-sensitive adhesive composition, which is a polymer of a monomer component containing 5 to 18 parts by mass of a carboxyl group-containing monomer (B).
[2] The pressure-sensitive adhesive composition according to the above [1], wherein the (meth) acrylic acid alkyl ester monomer (a) having 4 or less carbon atoms in the alkyl group contains n-butyl (meth) acrylate.
[3] The pressure-sensitive adhesive composition according to the above [1] or [2], wherein the carboxyl group-containing monomer (B) is acrylic acid.
[4] The pressure-sensitive adhesive composition according to any one of [1] to [3] above, wherein the pressure-sensitive adhesive resin (Y) is a rosin-based pressure-sensitive adhesive resin.
[5] The pressure-sensitive adhesive composition according to any one of [1] to [4] above, wherein the pressure-sensitive adhesive resin (Y) contains 13% by mass or less of a component having a molecular weight of 600 or less.
[6] The pressure-sensitive adhesive composition according to any one of [1] to [5] above, wherein the cross-linking agent (Z) is at least one selected from the group consisting of a metal chelate-based cross-linking agent and an isocyanate-based cross-linking agent. object.
[7] An adhesive tape having an adhesive layer composed of the adhesive composition according to any one of the above [1] to [6].
[8] An adhesive tape in which an adhesive layer composed of the adhesive composition according to any one of [1] to [6] above is laminated on at least one surface of a base material.
[9] The adhesive tape according to the above [8], wherein the base material is a pulp fiber nonwoven fabric containing 0.1 to 60% by mass of a rayon component.
[10] The adhesive tape according to the above [8], wherein the base material contains a thermoplastic resin and a plasticizer.
[11] The adhesive tape according to the above [10], wherein the thermoplastic resin is polyvinyl acetal.
[12] The adhesive tape according to the above [10] or [11], wherein the substrate is either a non-woven fabric made of a fiber containing the thermoplastic resin and a plasticizer, or a porous body having a large number of bubbles. ..
[13] The base material is a porous body containing a thermoplastic resin and a plasticizer and having a large number of bubbles.
The porous body has a loss coefficient of the first-order antiresonance frequency of 0.2 or more in the range of 0 to 50 ° C. measured by mechanical impedance measurement (MIM) according to ISO 16940, and 2 in the range of 0 to 30 ° C. The adhesive tape according to any one of the above [10] to [12], wherein the next antiresonance frequency is 800 Hz or less.
[14] The base material is a porous body containing polyvinyl acetal and a plasticizer and having a large number of bubbles.
The adhesive tape according to any one of [10] to [12] above, wherein the porous body has an elongation strain of 300% or more and a 50% compressive stress of 70 kPa or less.
[15] The base material is a non-woven fabric made of fibers containing polyvinyl acetal and a plasticizer.
The non-woven fabric has a coefficient of 100 to 800 g / m ² , and a non-woven fabric sample having a length of 10 cm, a width of 10 cm, and a thickness of 4 mm is placed on an iron plate having a length of 10 cm or more, a width of 10 cm or more, and a thickness of 1 cm, and has a constant falling ball height. The rebound coefficient (rebound height / falling ball height) when measuring the rebound height when a 1/2 inch SUS ball conforming to JIS B 1501 is dropped from the non-woven fabric sample toward the center is 0.1 or less. The adhesive tape according to any one of the above [10] to [12].
[16] The adhesive tape according to any one of [7] to [15] above, wherein the gel content of the adhesive layer is 30 to 50% by mass.
[17] The adhesive tape according to any one of the above [7] to [16], which uses a soft polyvinyl chloride resin as an adherend.
[18] The adhesive tape according to any one of the above [7] to [17], which is used for vehicle interiors.

According to the present invention, an adhesive composition having high adhesive strength to a difficult-to-adhere object such as polypropylene resin and suppressing a decrease in adhesive strength with time to a soft polyvinyl chloride resin, and the adhesive An adhesive tape using the agent composition can be provided.
Further, the present invention provides an adhesive composition capable of suppressing a decrease in adhesive strength with time even if a plasticizer is contained in the base material of the adhesive tape, and an adhesive tape using the adhesive composition. Can be done.

It is a schematic diagram of the evaluation method of the repulsion holding force.

[Adhesive composition]
The pressure-sensitive adhesive composition of the present invention has 100 parts by mass of an acrylic polymer (X) having a weight average molecular weight of 550,000 to 1,000,000 and 3 to 9 parts by mass of a tackifier resin (Y) having a softening point of 140 to 160 ° C. A pressure-sensitive adhesive composition containing a part and a cross-linking agent (Z), and the acrylic polymer (X) uses a polymer having a specific monomer component. In the present invention, the acrylic polymer (X) contains 60% by mass or more of the (meth) acrylic acid alkyl ester monomer (a) having an alkyl group having 4 or less carbon atoms (meth) acrylic acid alkyl ester monomer (A). It is a polymer of a monomer component containing 5 to 18 parts by mass of the carboxyl group-containing monomer (B) with respect to 100 parts by mass.
By using the pressure-sensitive adhesive composition of the present invention, the adhesive strength to an adherend such as a soft polyvinyl chloride resin is increased, and the adhesive strength is less likely to decrease with time. The reason is not clear, but it is estimated as follows. Usually, when the pressure-sensitive adhesive composition is attached to the surface of a sheet formed of a soft polyvinyl chloride resin and used, the plasticizer contained in the soft polyvinyl chloride sheet is a pressure-sensitive adhesive from the surface of the soft polyvinyl chloride sheet. It is considered that the adhesive layer formed by the composition is easily transferred to the adhesive layer, which reduces the adhesive strength.
On the other hand, the pressure-sensitive adhesive layer formed by the pressure-sensitive adhesive composition of the present invention contains an acrylic polymer containing a relatively large amount of carboxyl group-containing monomers. Therefore, the acrylic polymer is in a state of high acid value having a relatively high polarity, and easily inhibits the migration of a plasticizer having a relatively low polarity, and as a result, the decrease in the adhesive strength of the pressure-sensitive adhesive layer is suppressed. It is presumed that it will be done. Furthermore, the high molecular weight of the acrylic copolymer and, in some cases, the high crosslink density are added, and it is expected that the effect of suppressing the decrease in adhesive strength due to the inhibition of plasticizer migration will be enhanced.
Further, as will be described later, when the base material of the adhesive tape contains a plasticizer, the transfer of the plasticizer from the base material to the pressure-sensitive adhesive layer is also inhibited, thereby reducing the adhesive strength of the pressure-sensitive adhesive layer. Is presumed to be suppressed.
Hereinafter, each component constituting the pressure-sensitive adhesive composition of the present invention will be described.

<Acrylic polymer (X)>
The acrylic polymer (X) contained in the pressure-sensitive adhesive composition of the present invention contains (meth) acrylic acid containing 60% by mass or more of the (meth) acrylic acid alkyl ester monomer (a) having an alkyl group having 4 or less carbon atoms. It is a polymer of a monomer component containing 5 to 18 parts by mass of a carboxyl group-containing monomer (B) with respect to 100 parts by mass of the alkyl ester monomer (A).
In the present specification, (meth) acrylic acid indicates acrylic acid or methacrylic acid, and (meth) acrylate indicates acrylate or methacrylate.

((Meta) Acrylic Acid Alkyl Ester Monomer (A))
The (meth) acrylic acid alkyl ester monomer (A) contains 60% by mass or more of the (meth) acrylic acid alkyl ester monomer (a) having an alkyl group having 4 or less carbon atoms. When the content of the (meth) acrylic acid alkyl ester monomer (a) having 4 or less carbon atoms in the alkyl group is less than 60% by mass, the soft polyvinyl chloride of the pressure-sensitive adhesive layer formed by the pressure-sensitive adhesive composition may be used. Adhesive strength to the adherend tends to decrease. The content of the (meth) acrylic acid alkyl ester monomer (a) having 4 or less carbon atoms in the alkyl group in the (meth) acrylic acid alkyl ester monomer (A) is a viewpoint of suppressing a decrease in adhesive strength to soft polyvinyl chloride. Therefore, it is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 100% by mass.
Examples of the (meth) acrylic acid alkyl ester monomer (a) having an alkyl group having 4 or less carbon atoms include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, and n. -Butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate can be mentioned. These (meth) acrylic acid alkyl ester monomers can be used alone or in combination of two or more. Further, among the above, it is preferable to use n-butyl (meth) acrylate, and it is more preferable to use n-butyl (meth) acrylate alone. The content of n-butyl (meth) acrylate is preferably 60% by mass or more, preferably 80% by mass or more, based on the total amount of the (meth) acrylic acid alkyl ester monomer (a) having 4 or less carbon atoms in the alkyl group. It is more preferable, and 100% by mass is particularly preferable.

The (meth) acrylic acid alkyl ester monomer (A) may contain a (meth) acrylic acid alkyl ester monomer (b) having an alkyl group having 5 or more carbon atoms. Examples of the (meth) acrylic acid alkyl ester monomer (b) include 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, and lauryl (meth) acrylate. The content of the (meth) acrylic acid alkyl ester monomer (b) having 5 or more carbon atoms in the alkyl group in the (meth) acrylic acid alkyl ester monomer (A) is preferably 20% by mass or less, more preferably 10. Quality% or less.

(Carboxylic group-containing monomer (B))
The carboxyl group-containing monomer (B) is a monomer containing a carboxyl group in the molecule and polymerizable, and is preferably a vinyl-based monomer containing a carboxyl group. Examples of the carboxyl group-containing monomer (B) include (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, and crotonic acid, with (meth) acrylic acid being preferred, and acrylic acid being more preferred. Only one type of carboxyl group-containing monomer (B) may be used, or two or more types may be used in combination.

The monomer component for obtaining the acrylic polymer (X) contains 5 to 18 parts by mass of the carboxyl group-containing monomer (B) with respect to 100 parts by mass of the (meth) acrylic acid alkyl ester monomer (A). When the amount of the carboxyl group-containing monomer (B) is less than 5 parts by mass, the reactivity with the cross-linking agent described later is lowered, and the adhesive force of the pressure-sensitive adhesive composition to an adherend such as soft polyvinyl chloride is likely to be lowered. .. The reason for this is that when the amount of the carboxyl group-containing monomer (B) is small, the polarity of the acrylic polymer (X) is lowered, and the plasticizer soft polyvinyl chloride, which is a compound having a relatively low polarity, or the base material of the adhesive tape. It is considered that the transition from the adhesive composition to the pressure-sensitive adhesive composition is likely to occur.
On the other hand, when the carboxyl group-containing monomer (B) exceeds 18 parts by mass, the pressure-sensitive adhesive layer itself formed from the pressure-sensitive adhesive composition tends to become hard as the cross-linking progresses, and is covered with soft polyvinyl chloride or the like. Adhesive strength to the body tends to decrease. Further, when the carboxyl group-containing monomer (B) exceeds 18 parts by mass, the adhesiveness to a low-energy surface such as polypropylene resin tends to decrease.
The amount of the carboxyl group-containing monomer (B) is preferably 5 to 17 parts by mass, more preferably 6 to 15 parts by mass, based on 100 parts by mass of the (meth) acrylic acid alkyl ester monomer (A). It is more preferably 10 to 15 parts by mass.
The monomer component may contain other monomers other than the (meth) acrylic acid alkyl ester monomer (A) and the carboxyl group-containing monomer (B).
Examples of other monomers include monomers containing polar groups other than carboxyl groups, styrene-based monomers such as styrene, α-methylstyrene, o-methylstyrene, and p-methylstyrene.

(Weight average molecular weight of acrylic polymer (X))
The weight average molecular weight of the acrylic polymer (X) used in the pressure-sensitive adhesive composition of the present invention is 550,000 to 1,000,000. When the weight average molecular weight is less than 550,000, the adhesive force to an adherend such as soft polyvinyl chloride tends to decrease with time. On the other hand, when the weight average molecular weight exceeds 1 million, the adhesive layer tends to be hard, so that the adhesive force to an adherend having a complicated shape tends to decrease, and adhesion to a low energy surface such as polypropylene resin is likely to occur. The sex tends to decrease. The weight average molecular weight of the acrylic polymer (X) is preferably 600,000 to 800,000, more preferably 65 to 750,000.

<Manufacturing method of acrylic polymer (X)>
The method for producing the acrylic polymer (X) is not particularly limited, and examples thereof include a method in which the monomer component is radically polymerized in the presence of a polymerization initiator. As the polymerization method, a known method can be adopted, and examples thereof include solution polymerization, emulsion polymerization, suspension polymerization, and bulk polymerization.
The polymerization initiator is not particularly limited, and examples thereof include an organic peroxide-based polymerization initiator and an azo-based polymerization initiator.

Examples of the organic peroxide-based polymerization initiator include cumene hydroperoxide, benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, stearoyl peroxide, o-chlorobenzoyl peroxide, acetyl peroxide, and t-butyl hydroperoxide. , T-Butylperoxyacetate, t-Butylperoxyisobutyrate, 3,5,5-trimethylhexanoyl peroxide, t-butylperoxy-2-ethylhexanoate or di-t-butyl peroxide, etc. Can be mentioned.

The azo-based polymerization initiator is not particularly limited, and for example, 2,2'-azobisisobutyronitrile, 2,2'-azobis (2,4-dimethylvaleronitrile), 4,4'-azobis (4). -Cyanopentanoic acid), 2,2'-azobis (2-methylbutyronitrile) and the like.
Among the above-mentioned polymerization initiators, lauroyl peroxide, octanoyl peroxide, stearoyl peroxide, and 3,5,5-trimethylhexanoyl peroxide should be used from the viewpoint of reducing the odor of the acrylic polymer (X). Is preferable. In addition, one type of polymerization initiator may be used alone, or two or more types may be used in combination.
The amount of the polymerization initiator is not particularly limited, but is preferably 0.01 to 10 parts by mass, and more preferably 0.05 to 2 parts by mass with respect to 100 parts by mass of the monomer component.

<Adhesive-imparting resin (Y)>
The softening point of the tackifier resin (Y) contained in the pressure-sensitive adhesive composition of the present invention is 140 to 160 ° C. When the softening point is out of the above range, the adhesive force of the pressure-sensitive adhesive layer formed by the pressure-sensitive adhesive composition tends to decrease with time to an adherend such as soft polyvinyl chloride. The softening point of the tackifier resin (Y) is preferably 140 to 150 ° C. from the viewpoint of increasing the adhesive force of the pressure-sensitive adhesive layer to the adherend such as soft polyvinyl chloride and suppressing the decrease in the adhesive force with time. The softening point can be measured according to JIS K2207.
Examples of the type of tackifier resin (Y) include rosin-based resins such as petroleum resin-based tackifier resins, hydrogenated petroleum resin-based tackifier resins, rosindiol-based tackifier resins, and rosin ester-based tackifier resins, and terpene resins. , Phenolic resin, xylene resin, kumaron resin, ketone resin, and modified resins thereof. Among these, a rosin-based tackifier resin is preferable, and a rosin ester-based tackifier resin is more preferable, from the viewpoint of increasing the adhesive force to an adherend such as soft polyvinyl chloride and suppressing the adhesive force over time.
Examples of the rosin ester-based tackifier resin include disproportionated rosin ester, polymerized rosin ester, hydrogenated rosin ester, and rosin phenol-based resin.

The blending amount of the tackifier resin (Y) in the pressure-sensitive adhesive composition is 3 to 9 parts by mass with respect to 100 parts by mass of the acrylic polymer (X). If the blending amount of the tackifier resin is less than 3 parts by mass, the adhesive strength to a difficult-to-adhere object such as polypropylene tends to decrease, and it becomes difficult to hold the adhesive layer when the adherend is deformed. .. When the blending amount of the tackifier resin is more than 9 parts by mass, the movement of the plasticizer from the soft polyvinyl chloride or the base material to the pressure-sensitive adhesive layer is promoted in the state where the pressure-sensitive adhesive layer is laminated on the soft polyvinyl chloride or the base material. It is easy to do so, and the adhesive strength tends to decrease over time. Amount of tackifier resin (Y) blended in the pressure-sensitive adhesive composition from the viewpoint of increasing the adhesive strength to a difficult-to-attached body such as polypropylene resin and maintaining the adhesive strength to soft polyvinyl chloride or other adherends. Is preferably 3 to 8 parts by mass, and more preferably 4 to 7 parts by mass with respect to 100 parts by mass of the acrylic polymer (X).

The tackifier resin (Y) preferably contains 13% by mass or less of components having a molecular weight of 600 or less. By using such a tackifier resin, it is possible to suppress the volatile components generated from the tackifier resin to a lower level while maintaining the tackiness. Further, since the amount of low molecular weight components is small, the viscosity of the pressure-sensitive adhesive layer can be relatively increased, and the pressure-sensitive adhesive layer is formed from the soft polyvinyl chloride or the base material in a state where the pressure-sensitive adhesive layer is laminated on the soft polyvinyl chloride or the base material. The movement of the plasticizer to the plasticizer is likely to be hindered, and the adhesive strength is less likely to decrease over time. The molecular weight of the tackifier resin and its content can be measured by gel permeation chromatography (GPC) and calculated from polystyrene conversion values and area ratios.
Examples of the method for removing the component having a molecular weight of 600 or less from the tackifier resin include a method of heating and melting the tackifier resin above the softening point, a method of blowing steam, and the like.

<Crosslinking agent (Z)>
The pressure-sensitive adhesive composition of the present invention contains a cross-linking agent. By using the cross-linking agent, the cohesive force of the formed pressure-sensitive adhesive layer is enhanced, and the physical properties of the pressure-sensitive adhesive tape are improved. The cross-linking agent is not particularly limited, and examples thereof include isocyanate-based cross-linking agents, epoxy-based cross-linking agents, aziridine-based cross-linking agents, and metal chelate-based cross-linking agents. Among these, isocyanate-based cross-linking agents and metal chelate-based cross-linking agents are used. Agents are preferred.
Examples of the isocyanate-based cross-linking agent include tolylene diisocyanate, naphthylene-1,5-diisocyanate, and diphenylmethane diisocyanate, and examples of commercially available products include coronate L manufactured by Nippon Polyurethane Industry Co., Ltd. Examples of the metal chelate-based cross-linking agent include chelate compounds in which the metal atom is aluminum, zirconium, titanium, zinc, iron, tin and the like, and an aluminum chelate in which the central metal is aluminum is preferable. Examples of commercially available products include aluminum chelate A and aluminum chelate M manufactured by Kawaken Fine Chemicals Co., Ltd.
The content of the cross-linking agent in the pressure-sensitive adhesive composition is not particularly limited, but is preferably 0.005 to 5 parts by mass, and more preferably 0.01 to 5 parts by mass with respect to 100 parts by mass of the acrylic polymer (X). It is 1 part by mass, more preferably 0.02 to 0.1 part by mass.

<Other ingredients>
In addition to the acrylic polymer (X), tackifier resin (Y), and cross-linking agent (Z), the pressure-sensitive adhesive composition of the present invention contains solvents such as ethyl acetate, dimethyl sulfoxide, ethanol, acetone, and diethyl ether. Of the solvent, ethyl acetate is preferable from the viewpoint of suppressing the volatile components to a low level. The pressure-sensitive adhesive composition of the present invention may contain additives such as fillers, pigments, dyes and antioxidants.

<Gel fraction>
As will be described later, the pressure-sensitive adhesive composition of the present invention can be applied onto a substrate or the like and dried to form a pressure-sensitive adhesive layer. The gel fraction of the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition of the present invention inhibits the movement of the plasticizer from the soft polyvinyl chloride or the base material to the pressure-sensitive adhesive layer, and suppresses the decrease in adhesive strength over time. From the viewpoint of the above, 30 to 50% by mass is preferable, and 35 to 45% by mass is more preferable. The gel fraction can be measured by the method described in Examples.

[Adhesive tape]
The adhesive tape of the present invention contains an adhesive layer composed of the above-mentioned adhesive composition. The adhesive tape may be a non-support type having only an adhesive layer, or may have an adhesive layer made of an adhesive composition laminated on at least one surface of a base material. Among these, a double-sided adhesive tape in which an adhesive layer is laminated on both surfaces of the base material is preferable.
The method for producing the adhesive tape is not particularly limited, but for example, the acrylic polymer (X), the pressure-sensitive adhesive resin (Y), the cross-linking agent (Z), the solvent, and the like described above are added to the base material or the like as necessary. The pressure-sensitive adhesive composition containing the above-mentioned material can be applied and dried to form a pressure-sensitive adhesive layer on the substrate for production. Examples of the drying method include a method of drying in a drying oven such as an IR heater or an oven.

The base material is not particularly limited, and for example, Japanese paper, non-woven fabric, polyethylene, polyethylene terephthalate, polypropylene, polyurethane and other plastic films, metal foil, porous materials and the like can be used. Among these base materials, a non-woven fabric is preferably used as a base material from the viewpoint of workability and followability to an adherend such as soft polyvinyl chloride, and among the non-woven fabrics, from the viewpoint of environmental protection and retention performance against an adhesive layer. Pulp fiber non-woven fabric is more preferably used.

The texture of the pulp fiber non-woven fabric is not particularly limited, but is preferably 8 to 25 g / m ² , and more preferably 10 to 18 g / m ² . By setting the texture in such a range, the permeability and coatability of the pressure-sensitive adhesive composition can be improved. The thickness of the pulp fiber nonwoven fabric is not particularly limited, but is preferably 5 to 50 μm, more preferably 10 to 40 μm.
When a pulp fiber non-woven fabric is used as a base material, it is preferable to use a pulp fiber non-woven fabric containing a rayon component. The amount of the rayon component in the pulp fiber non-woven fabric containing the rayon component is preferably 0.1 to 60% by mass, more preferably 1 to 50% by mass, and the amount of the pulp fiber component is preferably 40 to 99% by mass. It is 9% by mass, more preferably 50 to 99% by mass. In addition to the rayon component, the pulp fiber non-woven fabric may contain other fibers such as Manila hemp, nylon, polyester, acrylonitrile, polypropylene, and polyvinyl alcohol, if necessary, but the content of the other fibers is preferable. It is 20% by mass or less, more preferably 5% by mass or less.
When a pulp fiber non-woven fabric containing a rayon component is used, in addition to being excellent from the viewpoint of workability and environmental protection, when the pressure-sensitive adhesive composition of the present invention is applied to the pulp fiber non-woven fabric to form a pressure-sensitive adhesive layer. , The pressure-sensitive adhesive layer is hard to be separated from the pulp fiber non-woven fabric, and the performance as a pressure-sensitive adhesive tape is improved.

It is also preferable to use a porous body as the base material. The porous body has a large number of bubbles and is made of a resin foam.

Further, in the present invention, the base material may contain a thermoplastic resin and a plasticizer. Further, even if a base material containing a plasticizer is used in this way, the use of the pressure-sensitive adhesive composition prevents the plasticizer from migrating from the base material to the pressure-sensitive adhesive layer, and the pressure-sensitive adhesive is used over time. The decrease in the adhesive strength of the layer is suppressed.
Examples of the thermoplastic resin include polyvinylidene fluoride, polytetrafluoroethylene, vinylidene fluoride-propylene hexafluoride copolymer, polyethylene trifluoride, acrylonitrile-butadiene-styrene copolymer, polyester, polyether, and the like. Examples thereof include polyamide, polycarbonate, polyacrylate, polymethacrylate, polyvinyl chloride, polyethylene, polypropylene, polystyrene, polyvinyl acetal, and ethylene-vinyl acetate copolymer. Of these, polyvinyl acetal or ethylene-vinyl acetate copolymer is preferable, and polyvinyl acetal is more preferable.

When the base material contains a thermoplastic resin and a plasticizer, the base material is preferably a non-woven fabric or a porous body. That is, the base material is preferably a polyvinyl acetal non-woven fabric made of fibers containing polyvinyl acetal and a plasticizer, or a porous body containing polyvinyl acetal and a plasticizer, and among these, the porous body is preferable. More preferred.
By making the base material a porous body, as will be described later, it becomes easy to improve at least one of the shock absorption property, vibration damping property, shape property, and sound insulation performance of the base material. Therefore, the porous body is preferably used in applications where the base material requires any of these performances.

The polyvinyl acetal is not particularly limited as long as it is a polyvinyl acetal obtained by acetalizing polyvinyl alcohol with an aldehyde, but polyvinyl butyral is preferable. Further, two or more kinds of polyvinyl acetals may be used in combination as needed.

The preferable lower limit of the acetalization degree of the polyvinyl acetal is 40 mol%, the preferable upper limit is 85 mol%, the more preferable lower limit is 60 mol%, and the more preferable upper limit is 75 mol%.
In the polyvinyl acetal, the preferable lower limit of the amount of hydroxyl groups is 15 mol%, and the preferable upper limit is 40 mol%. When the amount of hydroxyl groups is within this range, the compatibility with the plasticizer becomes high.
The degree of acetalization and the amount of hydroxyl groups can be measured according to, for example, JIS K 6728 “Polyvinyl butyral test method”.

The polyvinyl acetal can be prepared by acetalizing polyvinyl alcohol with an aldehyde.
The polyvinyl alcohol is usually obtained by saponifying polyvinyl acetate, and polyvinyl alcohol having a saponification degree of 70 to 99.8 mol% is generally used. The degree of saponification of the polyvinyl alcohol is preferably 80 to 99.8 mol%.
The preferable lower limit of the degree of polymerization of the polyvinyl alcohol is 500, and the preferable upper limit is 4000. When the degree of polymerization of the polyvinyl alcohol is 500 or more, the handleability of the obtained porous body becomes excellent. When the degree of polymerization of the polyvinyl alcohol is 4000 or less, molding of a porous body becomes easy. The more preferable lower limit of the degree of polymerization of the polyvinyl alcohol is 1000, and the more preferable upper limit is 3600.

The aldehyde is not particularly limited, but in general, an aldehyde having 1 to 10 carbon atoms is preferably used. The aldehyde having 1 to 10 carbon atoms is not particularly limited, and for example, n-butyraldehyde, isobutylaldehyde, n-barrelaldehyde, 2-ethylbutyraldehyde, n-hexylaldehyde, n-octylaldehyde, and n-nonylaldehyde are not particularly limited. , N-decylaldehyde, formaldehyde, acetaldehyde, benzaldehyde and the like. Of these, n-butyraldehyde, n-hexylaldehyde, and n-bareraldehyde are preferable, and n-butyraldehyde is more preferable. These aldehydes may be used alone or in combination of two or more.

The plasticizer is not particularly limited, and for example, an organic ester plasticizer such as a monobasic organic acid ester or a polybasic organic acid ester, a phosphoric acid plasticizer such as an organic phosphoric acid plasticizer, or an organic phosphite plasticizer, etc. Can be mentioned. Of these, organic ester plasticizers are preferred. The plasticizer is preferably a liquid plasticizer. The liquid plasticizer is a plasticizer that becomes liquid at normal temperature (23 ° C.) and normal pressure (1 atm).

The monobasic organic acid ester is not particularly limited, but for example, glycols such as triethylene glycol, tetraethylene glycol, and tripropylene glycol, and butyric acid, isobutyric acid, caproic acid, 2-ethylbutyric acid, heptyl acid, and n-octyl are used. Examples thereof include glycol esters obtained by reaction with monobasic organic acids such as acids, 2-ethylhexanoic acid, pelargonic acid (n-nonyl acid) and decyl acid. Of these, triethylene glycol dicaproic acid ester, triethylene glycol di-2-ethylbutyrate ester, triethylene glycol di-n-octyl acid ester, triethylene glycol di-2-ethylhexanoic acid ester and the like are preferable.

The above-mentioned multibasic organic acid ester is not particularly limited, and is, for example, an ester compound of a multibasic organic acid such as adipic acid, sebacic acid, and azelaic acid and an alcohol having a linear or branched structure having 4 to 8 carbon atoms. Can be mentioned. Of these, dibutyl sebacic acid ester, dioctyl azelaic acid ester, dibutyl carbitol adipate and the like are preferable.

The organic ester plasticizer is not particularly limited, and triethylene glycol di-2-ethylbutyrate, triethylene glycol di-2-ethylhexanoate, triethylene glycol dicaprylate, triethylene glycol di-n-octanoate, Triethylene Glycol Di-n-Heptanoate, Tetraethylene Glycol Di-n-Heptanoate, Tetraethylene Glycol Di-2-ethylhexanoate, Dibutyl Sevacate, Dioctyl Azelate, Dibutyl Carbitol Adipate, Ethylene Glycol Di-2-ethyl Butyrate, 1,3-propylene glycol di-2-ethylbutyrate, 1,4-butylene glycol di-2-ethylbutyrate, diethylene glycol di-2-ethylbutyrate, diethylene glycol di-2-ethylhexanoate, Dipropylene glycol di-2-ethylbutyrate, triethylene glycol di-2-ethylpentanoate, tetraethylene glycol di-2-ethylbutyrate, diethylene glycol dicapriate, dihexyl adipate, dioctyl adipate, hexyl adipate Cyclohexyl, diisononyl adipate, heptylnonyl adipate, dibutyl sebacate, oil-modified alkyd sebacate, adipate mixture of phosphate ester and adipate ester, adipate ester, alkyl alcohol with 4-9 carbon atoms and 4-9 carbon atoms Examples thereof include mixed adipate prepared from cyclic alcohol, adipate having 6 to 8 carbon atoms such as hexyl adipate, and the like.
The organic phosphoric acid plasticizer is not particularly limited, and examples thereof include tributoxyethyl phosphate, isodecylphenyl phosphate, and triisopropyl phosphate.

Further, as the plasticizer, triethylene glycol di-2-ethylhexanoate (3GO), triethylene glycol di-2-ethylbutyrate (3GH), tetraethylene glycol di-2-ethylhexanoate (4GO) , Dihexyl adipate (DHA) is preferably contained, and tetraethylene glycol di-2-ethylhexanoate (4GO) and triethylene glycol di-2-ethylhexanoate (3GO) are more preferable. In particular, it is more preferable to contain triethylene glycol di-2-ethylhexanoate (3GO).

The content of the plasticizer is not particularly limited, but the preferable lower limit is 5 parts by mass and the preferable upper limit is 60 parts by mass with respect to 100 parts by mass of the thermoplastic resin. When the content of the plasticizer is within this range, it becomes easy to increase at least one of sound insulation, shock absorption, vibration damping, and excipient. In addition, the plasticizer does not bleed out from the porous body. The more preferable lower limit of the content of the plasticizer is 20 parts by mass, and the more preferable upper limit is 55 parts by mass.
In many laminated glass interlayer films, the content of the plasticizer is about 20 to 55 parts by mass with respect to 100 parts by mass of a thermoplastic resin such as polyvinyl acetal. Therefore, for example, a discarded laminated glass interlayer film can be used. As it is, it can be used as a raw material for the base material of the present invention.
The thermoplastic resin and the plasticizer are preferably the main components in the base material, and the total amount of the thermoplastic resin and the plasticizer is usually 70% by mass or more, preferably 80% by mass based on the total amount of the base material. Above, more preferably 90% by mass or more.

In addition to the above-mentioned thermoplastic resin and plasticizer, the base material may contain additives such as an adhesive force modifier, a heat ray absorber, an ultraviolet shielding agent, an antioxidant, a light stabilizer, and an antistatic agent. Good. Further, in order to adjust the appearance of the obtained base material, a pigment such as carbon black, a dye or the like may be contained.

The open cell ratio of the porous body is, for example, 10% or more, preferably 14% or more, more preferably 20% or more, further preferably 30% or more, and more preferably 40% or more. It is more preferably present, and particularly preferably 50% or more. The upper limit of the open cell ratio is not particularly limited, but about 98% is a substantial upper limit.
By increasing the open cell ratio in this way, it becomes easy to improve at least one of the impact absorption, vibration damping, shape-forming, and sound insulation performance of the base material. In addition, it becomes easy to obtain the porous body of the first and second embodiments described later.
In the present specification, the open cell means that the cells forming the porous body are connected to each other.
The open cell ratio is defined as the volume ratio of the bubbles connected to the outside of the porous body with respect to the apparent volume of the porous body obtained by dimensional measurement, and can be measured by the pycnometer method described in JIS K7138. it can.

In the porous body, the preferable lower limit of the average cell diameter is 100 μm, and the preferable upper limit is 1000 μm. The more preferable lower limit of the average cell diameter is 120 μm, the more preferable upper limit is 500 μm, and the further preferable lower limit is 200 μm. By setting the average cell diameter within this range, it becomes easier to further improve at least one of the impact absorption, vibration damping, shape-forming, and sound insulation performance of the base material. In addition, it becomes easy to obtain the porous body of the first to second embodiments described later.

The porous body preferably has an average aspect ratio of bubbles of 2 or less. When the average aspect ratio of the bubbles is 2 or less, it becomes easier to further improve at least one of the impact absorption, vibration damping, shape-forming, and sound insulation performance of the base material. In addition, it becomes easy to obtain the porous body of the first to second embodiments described later. The average aspect ratio of the bubbles is more preferably 1.5 or less.

The average cell diameter can be measured by a method of observing the bubble wall portion and the void portion from a cross-sectional observation photograph of the bubble and measuring the size of the void portion.
Specifically, first, the porous body sample for measurement may be cut into a length of 50 mm and a width of 50 mm, immersed in liquid nitrogen for 1 minute, and then cut along a plane parallel to the thickness direction with a razor blade. After that, a 200-fold magnified photograph is taken using a digital microscope (manufactured by KEYENCE, product name VHX-900), and the bubble diameter is measured for all the bubbles existing on the cut surface having a length of 2 mm in the thickness direction. .. When the thickness of the porous body is less than 2 mm, it is advisable to prepare a plurality of samples.
The above operation is repeated 5 times at different measurement points, and the average value of all observed bubble diameters is taken as the average cell diameter. The diameter of each bubble is the diameter of the inscribed circle that maximizes the diameter when the inscribed circle inscribed in the observed bubble is drawn.

Further, the average aspect ratio of the bubbles can be measured by a method of measuring the major axis and the minor axis of the void portion from the cross-sectional observation photograph of the bubbles and calculating the ratio.
Specifically, when measuring the average cell diameter, the major axis and minor axis when an ellipse inscribed in each observed bubble is drawn are measured, and the major axis length is divided by the minor axis length. To find the aspect ratio. Then, the aspect ratio can be obtained for all the observed bubbles, and the average aspect ratio can be obtained by obtaining the average value of the obtained aspect ratios.

The porous body preferably has an apparent density of 500 kg / m ³ or less. By setting the apparent density to 500 kg / m ³ or less, excellent shapeability can be exhibited, and for example, it becomes easy to obtain the porous body of the second embodiment described later. The apparent density is preferably 300 kg / m ³ or less. When the apparent density is 300 kg / m ³ or less, it becomes easy to improve the shock absorption, vibration damping, shapeability, low fluidity, etc. of the base material. Then, it becomes easy to obtain the porous body of the first to second embodiments described later. The apparent density is more preferably 260 kg / m ³ or less, and further preferably 200 kg / m ³ or less.
The lower limit of the apparent density is not particularly limited, but the apparent density is preferably 50 kg / m ³ or more. When the apparent density is 50 kg / m ³ or more, the elongation strain can be easily adjusted within a predetermined range shown in the second embodiment described later, and the formability becomes good, and the second embodiment described later It becomes easy to obtain a porous body. From the viewpoint of improving the shapeability and making the elongation strain described later a better value, the apparent density is more preferably 60 kg / m ³ or more, and further preferably 80 kg / m ³ or more. It is preferably 100 kg / m ³ or more, and particularly preferably 100 kg / m ³ .
The apparent density can be measured by a method calculated from the measured weight and the apparent volume obtained by the dimensional measurement.

Further, the porous body preferably has a specific gravity of 0.3 or less. When the specific gravity is 0.3 or less, higher shock absorption can be exhibited. The specific gravity is more preferably 0.2 or less. The lower limit of the specific gravity is not particularly limited, but about 0.05 is a substantial lower limit. By setting the specific gravity of the porous body within such a range, the shock absorption of the obtained porous body is improved.
The specific gravity of the porous body does not mean the density of the porous body with respect to the density of water. For example, in the case of a foam, the ratio of the density after foaming to the ratio of the density before foaming, that is, "foaming". It means "after density / density before foaming". Specifically, from the measured weight and the apparent volume obtained by dimensional measurement, "density after foaming = measured weight after foaming / apparent volume after foaming", "density before foaming = measured weight before foaming / foaming". By calculating as "previous apparent volume", "specific weight = density after foaming / density before foaming" can be obtained. If the measured weight before foaming and the apparent volume before foaming are unknown, it can be calculated as specific gravity = 1 / foaming ratio.

The thickness of the porous body used in the present invention is preferably 10 mm or less. When the upper limit of the thickness of the porous body is within the above range, the obtained porous body is less likely to undergo shear fracture. The thickness of the porous body used in the present invention is preferably 50 μm or more. When the lower limit of the thickness of the porous body is within the above-mentioned preferable range, it becomes easier to further improve at least one of the impact absorption, vibration damping property, shape-forming property, and sound insulation performance of the obtained porous body. Further, when the thickness of the porous body is within the above range, the porous body can be suitably used as a base material of the adhesive tape.

The porous body may be crosslinked with a crosslinking agent. As the cross-linking agent, for example, when polyvinyl acetal is used as the thermoplastic resin, a compound capable of reacting with a hydroxyl group, an acetyl group, an acetal group or the like contained in the side chain of the polyvinyl acetal to cross-link between the polyvinyl acetals is used. It is possible to do. Specific examples thereof include epoxy compounds, isocyanate compounds and boric acid compounds. Further, for example, a polyfunctional (meth) acrylate compound such as trimethylolpropane triacrylate (TMPTA) can also be used as a cross-linking agent.
When a polyfunctional (meth) acrylate compound is used as the cross-linking agent in the porous body, it is preferable to use a photopolymerization initiator in combination. By using the photopolymerization initiator in combination, the porous body can be uniformly and reliably crosslinked. As the photopolymerization initiator, a conventionally known compound such as benzophenone can be used.

The base material used for the adhesive tape of the present invention is preferably a porous body as described above, but the porous body is one of the porous bodies of the first to second embodiments below. Is more preferable.

(First Embodiment)
The porous body of the first embodiment of the present invention has a loss coefficient of the first-order antiresonance frequency in the range of 0 to 50 ° C. measured by mechanical impedance measurement (MIM) according to ISO 16940 (hereinafter, simply “loss coefficient”). (Also referred to as) is 0.2 or more, and the secondary antiresonance frequency in the range of 0 to 30 ° C. is 800 Hz or less.
When the loss coefficient is 0.2 or more, the porous body exhibits high vibration absorption, loses sound energy, and can exhibit high sound insulation performance. The loss coefficient is preferably 0.3 or more. When the secondary antiresonance frequency is 800 Hz or less, the sound generated from the adherend can be made difficult for the human ear to perceive as noise.
Therefore, the porous body of the first embodiment can exhibit high sound insulation performance, and the adhesive tape using the porous body of the first embodiment as a base material uses the base material as a sound insulating material or a sound insulating material. It is suitable for the intended use.
The loss coefficient of the primary antiresonance frequency and the secondary antiresonance frequency can be measured by the central excitation method, and the maximum value of the loss coefficient in the range of 0 to 50 ° C. and 2 in the range of 0 to 30 ° C. Obtained as the maximum value of the next antiresonance frequency. At that time, as a sample, a laminated sample in which a porous body is fixed with double-sided tape (manufactured by Sekisui Chemical Co., Ltd., # 5782) between two glass plates having a width of 25 mm, a length of 305 mm, and a thickness of 2 mm is used. .. Before applying the double-sided tape for measurement, the double-sided tape is attached to the porous body in advance, or if the porous body has an adhesive layer, the surface on which the double-sided tape is not attached or the adhesive Double-sided tape (manufactured by Sekisui Chemical Industry Co., Ltd., # 5782) is attached only to the surface that does not have the agent layer.

The loss factor and the second-order antiresonance frequency can be achieved, for example, by adjusting the foaming state of the porous body. Specifically, it is preferable that the open cell ratio of the porous body is 20% or more, and by further increasing the open cell ratio, high sound insulation is exhibited, and the loss coefficient and the second-order antiresonance are exhibited. It becomes easy to adjust the frequency to a suitable value.
Further, in the present embodiment, it is preferable to use polyvinyl acetal as the thermoplastic resin as described above, but by using polyvinyl acetal, the loss coefficient of the primary antiresonance frequency and the secondary antiresonance frequency described above can be obtained. It becomes easy to adjust within a predetermined range. Further, it is better to adjust the average cell diameter, the average aspect ratio of the cells, the apparent density and the like within a desired range as described above.

(Second Embodiment)
The porous body of the second embodiment of the present invention is a porous body containing polyvinyl acetal and a plasticizer and having a large number of bubbles, and has an elongation strain of 300% or more and a compressive stress of 50%. It is 70 kPa or less. The porous body in the second embodiment is flexible and has excellent shapeability. Therefore, it becomes easy to shape the adhesive tape into various shapes by embossing or the like.

In the present specification, the elongation strain means a value indicating the degree of deformation applied to the porous body when the sheet-like porous body is subjected to elongational deformation in the uniaxial direction. When the elongation strain is 300% or more, the porous body can exhibit excellent impact resistance while being flexible. The elongation strain is preferably 400% or more, and more preferably 500% or more. The upper limit of the elongation strain is not particularly limited, but is substantially 800%.
In the present specification, the 50% compressive stress means a value indicating the stress applied to the porous body when 50% compressed in the thickness direction of the sheet-shaped porous body. When the 50% compressive stress is 70 kPa or less, the porous body of the present embodiment becomes flexible and can exhibit excellent shapeability. The 50% compressive stress is preferably 30 kPa or less, and more preferably 20 kPa or less. The lower limit of the 50% compressive stress is not particularly limited, but is substantially about 5 kPa.
The elongation strain and the 50% compressive stress can be measured by a method according to JIS K 6767.
Specifically, it is advisable to measure the elongation strain by a method of pulling at a tensile speed of 500 mm / min with a universal testing machine using a sample punched into a dumbbell-shaped No. 1 shape specified in JIS K 6251. Further, it is advisable to measure 50% compressive stress by a method of compressing a laminated sample obtained by laminating a sample cut into a square shape having a side of 50 mm until the laminated thickness becomes 25 mm or more at a compression rate of 10 mm / min with a universal tester. ..

The elongation strain and 50% compressive stress can be achieved by adjusting the foaming state of the porous body. Specifically, it is preferable that the open cell ratio of the porous body is 20% or more. By setting the open cell ratio to 20% or more, the 50% compressive stress of the obtained porous body can be adjusted within a predetermined range, and extremely high flexibility can be exhibited. From this point of view, the open cell ratio should be high as described above.
Further, by adjusting the apparent density or the like within a desired range as described above, it becomes easy to adjust the elongation strain or the like of the porous body within a predetermined range, and flexibility and shapeability can be imparted. Further, also in the present embodiment, it is better to adjust the average cell diameter, the average aspect ratio of the cells, and the like within the desired ranges as described above.

In the present invention, the method for producing the porous body is not particularly limited, and for example, a resin composition is prepared by blending a pyrolytic foaming agent with the above-mentioned thermoplastic resin, plasticizer and additives added as needed. Then, a method of heating the resin composition to a foaming temperature to decompose the pyrolytic foaming agent is preferable. When cross-linking the porous body, it is preferable to add a cross-linking agent to the above resin composition. Further, the cross-linking is preferably performed before foaming. For example, when the cross-linking of the porous body is performed by irradiating light such as ultraviolet rays, it is preferable to perform light irradiation before heating for foaming.

Here, in order to set the open cell ratio and the like in the above range and obtain, for example, the porous body of the first and second embodiments, in addition to selecting the thermoplastic resin and the plasticizer, thermal decomposition at the time of production It is important to set the type and blending amount of the mold foaming agent and the foaming temperature. Above all, setting the foaming temperature is important for achieving a high open cell ratio.
Specifically, the foaming temperature is preferably 180 ° C. or higher. At a temperature of 180 ° C. or higher, it is considered that the resin composition is sufficiently softened during foaming and the bubbles easily communicate with each other, so that open cells are likely to be generated. In particular, since such an increase in the open cell ratio is observed by using a resin composition containing polyvinyl acetal and a plasticizer, the porous body is continuous by containing polyvinyl acetal and a plasticizer. It becomes easy to increase the bubble ratio.

The thermal decomposition type foaming agent is not particularly limited as long as it has a decomposition temperature of about 120 to 240 ° C., and conventionally known ones can be used. Since the open cell ratio can be made higher, it is preferable to select the pyrolysis type foaming agent so that the foaming temperature is 180 ° C. or higher and the foaming temperature is higher than the decomposition temperature of the pyrolysis type foaming agent. .. More specifically, the foaming temperature is preferably 20 ° C. or higher, more preferably 50 ° C. or higher, and even more preferably 80 ° C. or higher with respect to the decomposition temperature of the thermally decomposable foaming agent.

Specific examples of the pyrolytic foaming agent include azodicarbonamide, N, N'-dinitrosopentamethylenetetramine, 4,4'-oxybis (benzenesulfonyl hydrazide), urea, sodium hydrogencarbonate, and the like. Examples thereof include a mixture thereof.
Among the above-mentioned pyrolyzable foaming agents, commercially available ones include, for example, Cellmic series (manufactured by Sankyo Kasei Co., Ltd.), Vinihole series, Cellular series, Neocerbon series (manufactured by Eiwa Kasei Kogyo Co., Ltd.) and the like. Be done.

The amount of the thermally decomposable foaming agent to be blended in the resin composition is not particularly limited, but the preferable lower limit is 2 parts by mass and the preferable upper limit is 20 parts by mass with respect to 100 parts by mass of the thermoplastic resin. When the blending amount of the pyrolysis type foaming agent is within this range, it becomes easy to produce a foam having an open cell ratio of 10% or more. Further, from the viewpoint of making it easier to increase the open cell ratio (for example, 20% or more), the more preferable lower limit of the blending amount of the pyrolysis foaming agent is 4 parts by mass, the more preferable lower limit is 5 parts by mass, and the more preferable upper limit is. It is 15 parts by mass.

Further, in the present invention, when the base material is composed of a material containing a thermoplastic resin and a plasticizer and is a non-woven fabric, it is preferably the non-woven fabric of the following third embodiment.

(Third Embodiment)
The nonwoven fabric of the third embodiment uses polyvinyl acetal as the thermoplastic resin, and is a polyvinyl acetal nonwoven fabric composed of fibers containing polyvinyl acetal and a plasticizer. The nonwoven fabric of the third embodiment has a basis weight of 100 to 800 g / m ² and a rebound coefficient (rebound height / falling ball height) of 0.1 or less.
By setting the basis weight and the rebound coefficient within the above ranges, the non-woven fabric of the present embodiment has high shock absorption, and is suitable for use in an adhesive tape that requires shock absorption, and is more specific. Is preferable when the base material is used as a sound insulating material, a shock absorbing material, or a vibration absorbing material.
The bounce coefficient is defined as a non-woven fabric sample having a length of 10 cm, a width of 10 cm, and a thickness of 4 mm placed on an iron plate having a length of 10 cm or more, a width of 10 cm or more, and a thickness of 1 cm, and from a constant falling ball height toward the center of the non-woven fabric sample. It is obtained by measuring the bounce height when a 1/2 inch SUS ball conforming to JIS B 1501 is dropped.

When the thickness of the non-woven fabric to be measured is less than 4 mm, the above-mentioned non-woven fabric sample is prepared by stacking the non-woven fabrics in the thickness direction until the thickness exceeds 4 mm and then shaving to a thickness of 4 mm. Good. When the thickness of the non-woven fabric to be measured exceeds 4 mm, it is advisable to cut it so that the thickness becomes 4 mm to prepare a non-woven fabric sample. If it is difficult to cut to a thickness of 4 mm accurately, an average thickness of 4 mm ± 0.1 mm is acceptable. The thickness of the nonwoven fabric sample may be adjusted by an appropriate mechanical device.
The environment at the time of measuring the bounce coefficient is a temperature of 23 ° C. and a humidity of 50% Rh.
Further, the constant falling ball height is, for example, 10 cm, 20 cm, or 30 cm. In the present invention, the bounce coefficient may be in a predetermined range in any one case, but in all cases, a predetermined range. It is better to become.

As the polyvinyl acetal, plasticizer, additive and the like used for the non-woven fabric of the present embodiment, the same ones as those described above can be used.
As described above, the non-woven fabric uses polyvinyl acetal as the thermoplastic resin, contains polyvinyl acetal and a plasticizer, and appropriately adjusts the texture, average diameter, etc. of the non-woven fabric to reduce the bounce coefficient to 0.1 or less. It is possible.

A preferred lower limit of the basis weight of the nonwoven fabric of the present embodiment is 150 g / ^{m 2,} a preferred upper limit is 660 g / ^{m 2,} and more preferable lower limit is 200 g / ^{m 2,} and more preferable upper limit is 500 g / ^{m 2.}
Further, the preferable lower limit of the average diameter (average fiber diameter) of the fibers constituting the nonwoven fabric of the present embodiment is 50 μm, and the preferable upper limit is 2 mm. When the average fiber diameter (average fiber diameter) is within this range, higher shock absorption can be exhibited. The more preferable lower limit of the average fiber diameter (average fiber diameter) is 100 μm, and the more preferable upper limit is 1 mm.

In the present embodiment, the average diameter (average fiber diameter) of the fibers constituting the non-woven fabric is preferably 1/2 or less, more preferably 1/3 or less, and 1/4 of the thickness of the non-woven fabric. The following is more preferable. The average fiber diameter (average fiber diameter) of the fibers constituting the non-woven fabric is preferably 1/100 or more, more preferably 1/50 or more, and 1/10 or more with respect to the thickness of the non-woven fabric. Is even more preferable.
When the ratio of the average diameter of the fibers constituting the non-woven fabric to the thickness of the non-woven fabric is not more than the above-mentioned preferable value, higher impact absorption can be exhibited.

From the viewpoint of improving the handleability of the adhesive tape, the preferable upper limit of the thickness of the nonwoven fabric used as the base material is 10 mm, the more preferable upper limit is 4 mm, the particularly preferable upper limit is 0.5 mm, and the most preferable upper limit is It is 0.3 mm. The preferable lower limit of the thickness is 20 μm. When the thickness is 20 μm or more, the shock absorption of the non-woven fabric is further improved. The more preferable lower limit of the thickness of the nonwoven fabric of the present embodiment is 50 μm, the more preferable lower limit is 100 μm, the particularly preferable lower limit is 150 μm, and the most preferable lower limit is 500 μm.

In the nonwoven fabric of the third embodiment, for example, a resin composition containing polyvinyl acetal, a plasticizer, an additive, etc. was extruded into a strand shape by an extruder, and then a strand-shaped body cut to an appropriate length was laminated. The laminate can be produced by thermocompression bonding using a press machine. At this time, the basis weight of the obtained non-woven fabric can be adjusted by adjusting the diameter and length of the strand-shaped body and the heat compression conditions.

The use of the adhesive tape of the present invention is not particularly limited, but is used for vehicle parts such as automobiles, aircrafts, and ships, building parts, electronic parts, living parts such as carpet linings, household and commercial electric appliances, and the like. It can be used for all purposes. Among them, it is preferably used in vehicles, houses, electronic devices, etc., more preferably used for vehicle members, and further preferably used for vehicle interiors.

Further, in the present invention, it is also preferable to use a soft polyvinyl chloride resin as an adherend. The soft polyvinyl chloride resin means polyvinyl chloride containing a plasticizer, and the content of the plasticizer is usually 5% by mass or more of the total amount of the soft polyvinyl chloride resin, preferably 10 to 80% by mass. %, More preferably 10 to 50% by mass.
The type of plasticizer contained in the soft polyvinyl chloride resin is not particularly limited, and for example, dimethylphthalate (DMP), diethylphthalate (DEP), dibutylphthalate (DBP), di-2-ethylhexylphthalate (DOP), di Phthalate-based plasticizers such as n-octylphthalate (N-DOP), diheptylphthalate (DHP), diisodecylphthalate (DIDP), butylbenzylphthalate (BBP), diisononylphthalate (DINP), di-2-ethylhexyl adipate What is contained in ordinary soft polyvinyl chloride resins such as fatty acid ester-based plasticizers such as (DOA), diisobutyl adipate (DIBA), dibutyl adipate (DBA), diisodecyl adipate (DIDA), and butyl oleate (BO). Can be used.
Further, since the adhesive tape of the present invention has good adhesive strength to polyolefin resins such as polyethylene resin and polypropylene resin, it is a double-sided adhesive tape, and the adherend on one side is a polyolefin resin such as polyethylene resin and polypropylene resin. It is also possible to use a soft polypropylene resin as the adherend on the other side.

The present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

(Example 1)
<Manufacturing of acrylic polymer>
100 parts by mass of n-butyl acrylate and 11 parts by mass of acrylic acid were introduced into the reaction vessel to obtain a monomer component. The monomer component is dissolved in ethyl acetate, 0.1 part by mass of lauroyl peroxide as a polymerization initiator is added at the reflux point, and the mixture is refluxed at 70 ° C. for 5 hours to obtain an acrylic weight having a weight average molecular weight of 720,000. A coalesced solution was obtained.
<Manufacturing of adhesive composition and adhesive tape>
A polymerized rosin ester-based adhesive in which the content of a component having a molecular weight of 600 or less is 13% by mass with respect to 100 parts by mass of the acrylic polymer which is a non-volatile component of the acrylic polymer solution in the obtained acrylic polymer solution. The imparting resin (softening point 140) was added to 6.3 parts by mass, and aluminum chelate, which is a metal chelate-based cross-linking agent, was added to 0.054 parts by mass as a cross-linking agent. Then, it was mixed uniformly to obtain a pressure-sensitive adhesive composition.
Next, the pressure-sensitive adhesive composition was applied to both sides of a polyethylene terephthalate film having a thickness of 50 μm, dried at 120 ° C. for 5 minutes, and a double-sided pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer having a thickness of 60 μm laminated on both sides of the polyethylene terephthalate film. Got
Weight average molecular weight of acrylic polymer, gel fraction of pressure-sensitive adhesive layer, adhesive strength retention rate (%) to adherend (soft polyvinyl chloride sheet) containing phthalate ester for the double-sided adhesive tape, repulsion retention The strength and the adhesive strength to the polypropylene resin were evaluated as follows. The results are shown in Table 1.

(Examples 2 to 8 and Comparative Examples 1 to 9)
An acrylic polymer was obtained in the same manner as in Example 1 except that the composition of the monomer was changed as shown in Table 1 or 2. Next, a double-sided adhesive tape was obtained in the same manner as in Example 1 except that the type and blending amount of the tackifier resin and the type and blending amount of the cross-linking agent were changed as shown in Table 1 or 2.
The adhesive tape had an adhesive strength retention rate (%), a repulsive holding strength, and an adhesive strength to a polypropylene resin for an adherend (soft polyvinyl chloride sheet) containing a phthalate ester by the following methods. The results are shown in Tables 1 and 2.
The types of pressure-sensitive adhesive-imparting resin and cross-linking agent used in Tables 1 and 2 are as follows.
<Adhesive-imparting resin>
Polymerized rosin ester-based tackifier resin (rosin-based (low molecular weight cut)): The content of components having a softening point of 140 ° C. and a molecular weight of 600 or less is 13% by mass.
Polymerized rosin ester-based tackifier resin (rosin-based (normal product)): The content of components with a softening point of 160 ° C and a molecular weight of 600 or less is 33% by mass.
Terpene phenolic adhesive resin ・ ・ ・ Softening point 150 ℃
<Crosslinking agent>
Metal chelate cross-linking agent ... Aluminum chelate, "M-A5DT" manufactured by Soken Chemical Co., Ltd.
Isocyanate-based cross-linking agent ... "Coronate L" manufactured by Nippon Polyurethane Industry Co., Ltd.
Epoxy cross-linking agent ... "E-AX" manufactured by Soken Chemical Co., Ltd.

[Measurement method, evaluation method]
<Molecular weight of (meth) acrylic polymer>
The weight average molecular weight of the (meth) acrylic polymer was calculated as a polystyrene-equivalent value using gel permeation chromatography (GPC) using the (meth) acrylic polymer before cross-linking as a measurement sample. The GPC measurement was performed by a GPC device manufactured by Tosoh Corporation, HLC-8220 GPC.
<Softening point of adhesive resin>
Measured according to JIS K2207.

<Gel fraction>
W1 (g) was collected from the pressure-sensitive adhesive layer of the double-sided adhesive tape, and the insoluble matter when the collected pressure-sensitive adhesive component was immersed in ethyl acetate at 23 ° C. for 24 hours was filtered through a 200-mesh wire mesh. The residue on the wire mesh was dried by heating at 110 ° C., the weight W2 (g) of the obtained dried residue was measured, and the gel fraction (crosslinking degree) was calculated by the following formula.
Gel fraction (mass%) = 100 x W2 / W1

<Adhesive strength retention rate (%) for adherends (soft polyvinyl chloride sheets) containing phthalates>
The adhesive strength maintenance rate was calculated by the following formula.
Adhesive strength maintenance rate (%) = 100 x (adhesive strength over time / initial adhesive strength)
(1) Initial Adhesive Strength A PET film having a thickness of 23 μm was attached to one surface of the double-sided adhesive tapes of each Example and Comparative Example so as not to allow air to enter. Next, the adhesive layer side of the double-sided adhesive tape attached to the PET film, which is not attached to the PET film, is placed on the soft polyvinyl chloride having a thickness of 300 μm in an environment of room temperature (23 ° C.) and a relative humidity of 50%. It was attached to the surface of the sheet (containing 30% by mass of DINP as a plasticizer) at a speed of 30 mm / min using a 2 kg pressure-bonded rubber roller.
After being left in this environment for 30 minutes, the 180-degree peel strength at a width of 25 mm was measured at a speed of 3 mm / min according to the method of JIS Z0237, and this was defined as the initial adhesive strength (N / 25 mm).
(2) Adhesive strength over time A PET film having a thickness of 23 μm was attached to one surface of the double-sided adhesive tapes of each Example and Comparative Example so as not to allow air to enter. Next, the adhesive layer side of the double-sided adhesive tape attached to the PET film, which is not attached to the PET film, is placed on the soft polyvinyl chloride having a thickness of 300 μm in an environment of room temperature (23 ° C.) and a relative humidity of 50%. It was attached to the surface of the sheet (containing 30% by mass of DINP as a plasticizer) at a speed of 30 mm / min using a 2 kg pressure-bonded rubber roller. Then, it was left in an environment of 60 ° C. for 72 hours, then left at room temperature for 30 minutes, and then the 180 degree peel strength in a width of 25 mm was measured at a rate of 3 mm / min according to the method of JIS Z0237, and this was measured over time. Adhesive strength (N / 25 mm) was used.

<Repulsion holding power for adherends containing phthalates>
FIG. 1 shows a schematic diagram of a method for evaluating the repulsive holding force.
One side of the double-sided adhesive tape 11 of each example and comparative example was placed on the surface of a soft polyvinyl chloride sheet 12 having a thickness of 300 μm (containing 30% by mass of DINP as a plasticizer) using a 2 kg pressure-bonding rubber roller at 30 mm / min. A polyvinyl chloride sheet with a double-sided adhesive tape was prepared by pasting at the speed of. The polyvinyl chloride sheet with the double-sided adhesive tape is cut into 15 mm × 40 mm, and extends from a part of the upper surface (10 mm) of the polypropylene plate 13 having a thickness of 5 mm to a part of the lower surface (25 mm) through the side surface. It was attached at a speed of 30 mm / min using a 2 kg crimping rubber roller so as to form a character (Fig. 1). In this state, the polypropylene plate 13 was allowed to stand for 2 weeks under the conditions of 60 ° C. and 90% relative humidity, and the soft polyvinyl chloride sheet was peeled off at a part of the upper surface (10 mm) or a part of the lower surface (25 mm) of the polypropylene plate 13. The repulsive holding force of the double-sided adhesive tape was evaluated by confirming whether or not
A is the one in which the soft polyvinyl chloride sheet is not peeled off, and B is the one in which the soft polyvinyl chloride sheet is not peeled off but the sheet is partially lifted and the adhesive strength is weak. , The peeling of the polyvinyl chloride sheet was evaluated as C.

<Adhesive strength to polypropylene resin>
A PET film having a thickness of 23 μm was attached to one surface of the double-sided adhesive tapes of each Example and Comparative Example so as not to allow air to enter. Next, the adhesive layer side of the double-sided adhesive tape attached to the PET film, which is not attached to the PET film, is formed of a polypropylene resin sheet having a thickness of 300 μm in an environment of room temperature (23 ° C.) and a relative humidity of 50%. It was attached to the surface at a speed of 30 mm / min using a 2 kg crimping rubber roller.
After being left in this environment for 30 minutes, the 180-degree peel strength at a width of 25 mm was measured at a speed of 3 mm / min according to the method of JIS Z0237, and this was defined as the adhesive strength (N / 25 mm) to the polypropylene resin.

(Example 9)
An adhesive composition was obtained in the same manner as in Example 1. The pressure-sensitive adhesive composition was applied to both sides of a pulp fiber non-woven fabric (thickness 30 μm, grain size 14 g / m ² ) containing 10 ± 2% by mass of rayon component and 86 ± 3% by mass of pulp fiber, and 5 at 120 ° C. The non-woven fabric was dried for a minute to obtain a double-sided adhesive tape in which adhesive layers having a thickness of 60 μm were laminated on both sides of the non-woven fabric.
The adhesive tape was evaluated for detachment of the adhesive from the non-woven fabric.

(Example 10)
A double-sided adhesive tape was obtained in the same manner as in Example 9 except that a pulp fiber non-woven fabric containing no rayon component (thickness 30 μm, grain size 14 g / m ² ) was used.
The adhesive tape was evaluated for detachment from the non-woven fabric by the method shown below.

<Evaluation of adhesive layer detachment from non-woven fabric>
A double-sided adhesive tape of Example 6 or 7 cut into a width of 25 mm and a length of 130 mm was attached to one end of a test plate (soft polyvinyl chloride sheet) and reciprocally pressure-bonded with a 1 kg roller. After crimping, leave it at a temperature of 80 ± 2 ° C. for 1 hour, and then hang a weight with a load of 9.8 ± 0.049 N on the lower end of the test piece to see if the weight falls within 4 hours. I confirmed. When the weight falls, it means that the adhesive layer has been separated from the non-woven fabric.
The release of the pressure-sensitive adhesive layer from the non-woven fabric was evaluated based on the following evaluation criteria.
A ... The adhesive layer did not separate from the non-woven fabric.
B ... It was confirmed that the adhesive layer was separated from the non-woven fabric.

As is clear from the results of Examples 1 to 8, the adhesive tape using the pressure-sensitive adhesive composition of the present invention containing a specific type of acrylic polymer and a pressure-imparting resin in a specific amount adheres to a soft polyvinyl chloride sheet. The force retention rate and repulsion holding force were good. Furthermore, from the results of Examples 9 to 10, it was found that when a non-woven fabric containing a rayon component was used as a base material, the adhesive was less likely to be detached from the base material.
On the other hand, the adhesive tape using the pressure-sensitive adhesive composition shown in Comparative Examples 1 to 9 which does not satisfy the requirements of the present invention does not have one or both of the adhesive strength retention rate and the repulsion retention force with respect to the soft polyvinyl chloride sheet. It was enough.
Further, the adhesive tape containing a certain amount of the tackifier resin in the pressure-sensitive adhesive layer used in Examples 1 to 8 had good adhesive strength to the polypropylene resin. On the other hand, the adhesive tape containing no tackifier resin used in Comparative Examples 5 to 7 was easily peeled off from the polypropylene plate, and a good evaluation could not be obtained in the evaluation of the repulsive holding force.

<Adhesive tape having a porous body of the first embodiment>
(Example 11)
(1) Production of Porous Body 40 parts by mass of triethylene glycol di-2-ethylhexanoate (3GO) as a plasticizer and Celmic CE as a pyrolysis foaming agent with respect to 100 parts by mass of polyvinyl butyral (PVB1). (Manufactured by Sankyo Kasei Co., Ltd., decomposition temperature 208 ° C.) was added in an amount of 4 parts by mass to obtain a resin composition. The obtained resin composition was sufficiently kneaded with a mixing roll at 110 ° C. and then extruded with an extruder to obtain a sheet-like body. PVB1 has a hydroxyl group content of 34 mol%, an acetylation degree of 1.0 mol%, a butyralization degree of 65 mol%, and an average degree of polymerization of 1650. The obtained sheet-like body was decomposed by a pyrolyzable foaming agent at a foaming temperature of 220 ° C. in an oven to obtain a porous body made of a resin foam. The thickness of the obtained porous body was 4 mm.
(2) Production of Adhesive Tape An adhesive composition similar to that in Example 1 is applied to one side of a porous body (base material), dried at 120 ° C. for 5 minutes, and has a thickness of 60 μm on one side of the base material. A single-sided adhesive tape on which an adhesive layer was laminated was obtained.

(Example 12)
A porous body having a thickness of 4 mm was produced in the same manner as in Example 11 except that the blending amount of the pyrolytic foaming agent was as shown in Table 4, and the porous body was used in the same manner as in Example 11. A single-sided adhesive tape was produced by the method.

(Comparative Example 10)
The same as in Example 11 except that the pressure-sensitive adhesive composition used was changed from the same pressure-sensitive adhesive composition as in Example 1 to the same pressure-sensitive adhesive composition as in Comparative Example 4, a porous body having a thickness of 4 mm and one-sided adhesion. Manufactured the tape.

(Comparative Example 11)
The pressure-sensitive adhesive composition used was the same as in Example 12 except that the pressure-sensitive adhesive composition used in Example 1 was changed to the same pressure-sensitive adhesive composition as in Comparative Example 4. Manufactured the tape.

With respect to the porous bodies produced in Examples 11 and 12 and Comparative Examples 10 and 11, the loss coefficient of the primary antiresonance frequency and the secondary antiresonance frequency are measured by the method described in the specification, and the following evaluation criteria are used. The sound insulation performance was evaluated according to the above. The results are shown in Table 4.

(Evaluation of sound insulation performance)
The sound transmission loss was measured by the sound intensity method according to JIS A 1441. The measurement temperature was 20 ° C., and the frequency range was 100 to 10,000 Hz for each 1/3 octave band. The sample was a resin foam sample (thickness about 4 mm) sandwiched between 2 mm thick glass and fixed with double-sided tape (manufactured by Sekisui Chemical Co., Ltd., # 5782). At that time, the double-sided tape was not attached to the surface having the adhesive layer, and the double-sided tape (manufactured by Sekisui Chemical Co., Ltd., # 5782) was attached only to the surface not having the adhesive layer. The size (opening surface) was 500 mm × 500 mm. The incident power was calculated from the average sound pressure level of 5 points in the reverberation room, and the transmitted power was calculated from the acoustic intensity of 5 × 5 = 25 points in the measurement area (500 mm × 500 mm).
The sound insulation performance was evaluated according to the following criteria.
Create a frequency-transmission loss graph, and "A" when the difference in transmission loss between the first maximum value on the low frequency side and the adjacent minimum value is sufficiently small, and "A" when the difference in transmission loss is large. It was evaluated as "B".

(Plasticizer resistance evaluation)
The single-sided adhesive tapes of Examples 11 to 12 and Comparative Examples 10 to 11 were evaluated by the following evaluation methods. The evaluation results are shown in Table 4.
(Preparation of test piece)
The single-sided adhesive tape obtained in each Example and Comparative Example was cut into a width of 25 mm and a length of 150 mm, and a 2 kg rubber roller was applied to SUS304 (surface BA finish) specified in JIS G4305 at 10 mm / sec according to JIS Z0237. It was reciprocated once at a speed and crimped.
(Initial adhesive strength)
The single-sided adhesive tape obtained in the above preparation of the test piece was left at 23 ° C. and 50% RH for 20 minutes after crimping, and then a 90-degree peeling test was carried out in accordance with JIS Z0237 with the average value of 3. The initial adhesive strength (N / 25 mm) was used. The peeling speed was 300 mm / min.
(Adhesive strength over time)
The test piece obtained in the above test piece preparation was left to stand in an atmosphere of 60 ° C. for 72 hours, and then left to stand at 23 ° C. and 50% RH for 30 minutes, and then a 90 degree peeling test was performed in test number 3 according to JIS Z0237. The average value was taken as the adhesive strength over time (N / 25 mm).
(Adhesive strength maintenance rate)
Using the initial adhesive strength and the adhesive strength over time obtained above, the adhesive strength retention rate (%) was calculated by the following formula.
Adhesive strength maintenance rate (%) = 100 x (adhesive strength over time / initial adhesive strength)
The adhesive strength retention rate of the single-sided adhesive tape using the same adhesive composition as in Example 1 is significantly higher than the adhesive strength retention rate of the single-sided adhesive tape using the same adhesive composition as in Comparative Example 4. The case where it was improved was evaluated as A, and the case where there was no change was evaluated as B.

<Adhesive tape having a porous body of the second embodiment>
(Example 13)
(1) Production of porous body 40 parts by mass of triethylene glycol di-2-ethylhexanoate (3GO) as a plasticizer and vinylhole AC as a pyrolysis foaming agent with respect to 100 parts by mass of polyvinyl butyral (PVB2). A resin composition was obtained by adding 3 parts by mass of # 3 (manufactured by Eiwa Kasei Kogyo Co., Ltd., decomposition temperature 208 ° C.) and 0.8 parts by mass of carbon black (manufactured by Tokai Carbon Co., Ltd., Seest SP). The obtained resin composition was sufficiently kneaded with a mixing roll at 110 ° C. and then extruded with an extruder to obtain a sheet-like body. PVB2 has a hydroxyl group content of 31 mol%, an acetylation degree of 0.7 mol%, a butyralization degree of 68.3 mol%, and an average degree of polymerization of 1800.
The obtained sheet-like body was decomposed by a pyrolyzable foaming agent at a foaming temperature of 230 ° C. in an oven to obtain a porous body having a thickness of 4 mm made of a resin foam.
(2) Production of Adhesive Tape An adhesive composition similar to that in Example 1 is applied to one side of a porous body (base material), dried at 120 ° C. for 5 minutes, and has a thickness of 60 μm on one side of the base material. A single-sided adhesive tape on which an adhesive layer was laminated was obtained.

(Example 14)
A porous body having a thickness of 4 mm was produced in the same manner as in Example 13 except that the blending amount of the pyrolytic foaming agent was as shown in Table 5, and the porous body was used on one side as in Example 13. Adhesive tape was manufactured.

(Comparative Example 12)
The pressure-sensitive adhesive composition used was the same as in Example 13 except that the pressure-sensitive adhesive composition used in Example 1 was changed to the same pressure-sensitive adhesive composition as in Comparative Example 4. Manufactured the tape.

(Comparative Example 13)
The pressure-sensitive adhesive composition used was the same as in Example 14 except that the pressure-sensitive adhesive composition used in Example 1 was changed to the same pressure-sensitive adhesive composition as in Comparative Example 4. Manufactured the tape.

With respect to the porous bodies produced in Examples 13 and 14 and Comparative Examples 12 and 13, elongation strain and 50% compressive stress were measured by the method described in the specification. In addition, the shapeability and flexibility of the adhesive tapes obtained in Examples 13 and 14 and Comparative Examples 12 and 13 were evaluated according to the following evaluation criteria. Further, the plasticizer resistance was evaluated by the same method as in Examples 11 and 12 and Comparative Examples 10 and 11. The results are shown in Table 5.

(Evaluation of formability)
The adhesive tape was placed on a polycarbonate corrugated plate with a pitch of 32 mm and a valley depth of 9 mm so that only the peaks of the corrugated plate were in contact with each other, and the adhesive tape was stretched and attached so as to press against the valleys. .. At this time, the presence or absence of tearing and local thinning of the base material was observed, and the shapeability was evaluated according to the following criteria.
A: No tearing or thinning B: Tearing or thinning

(Evaluation of flexibility)
A 1/2 inch diameter SUS ball was allowed to stand in the valley of the adhesive tape shaped into a corrugated sheet for 1 minute. When the SUS balls were removed, it was observed whether there were any traces of the SUS balls sinking, and the flexibility was evaluated according to the following criteria.
A: Traces of sinking SUS balls were seen B: Traces could not be confirmed

<Adhesive tape having the non-woven fabric of the third embodiment>
(Example 15)
(1) Production of Nonwoven Fabric A resin composition was obtained by adding 40 parts by mass of triethylene glycol di-2-ethylhexanoate (3GO) as a plasticizer to 100 parts by mass of polyvinyl butyral (PVB1). The obtained resin composition was sufficiently kneaded with a mixing roll and then extruded into a strand shape having a diameter of 1 mm using an extruder.
The obtained strands were cut to a length of 10 cm and then randomly laminated so that the basis weight after thermocompression bonding was 400 g / m ² . The obtained laminate was thermocompression bonded using a press machine, so that the contact portions of the strands were thermocompression bonded to each other to obtain a non-woven fabric.
The average diameter of the fibers constituting the obtained non-woven fabric (average fiber diameter) was 1 mm, which was the same as the diameter of the strands. In thermocompression bonding, the distance between the press plates was 4 mm, the press temperature was 130 ° C., and the press time was 3 minutes.
(2) Production of Adhesive Tape An adhesive composition similar to that in Example 1 was applied to one side of a non-woven fabric, dried at 120 ° C. for 5 minutes, and an adhesive layer having a thickness of 60 μm was laminated on one side of the base material. A single-sided adhesive tape was obtained.

(Example 16)
A non-woven fabric was produced in the same manner as in Example 12 except that the strands were laminated so that the basis weight after thermocompression bonding was 300 g / m ^2, and the non-woven fabric was used to apply a single-sided adhesive tape in the same manner as in Example 15. Obtained.

(Comparative Example 14)
A non-woven fabric and a single-sided adhesive tape were produced in the same manner as in Example 15 except that the pressure-sensitive adhesive composition used was changed from the same pressure-sensitive adhesive composition as in Example 1 to the same pressure-sensitive adhesive composition as in Comparative Example 4.

(Comparative Example 15)
A non-woven fabric and a single-sided adhesive tape were produced in the same manner as in Example 16 except that the pressure-sensitive adhesive composition used was changed from the same pressure-sensitive adhesive composition as in Example 1 to the same pressure-sensitive adhesive composition as in Comparative Example 4.

With respect to the nonwoven fabrics produced in Examples 15 and 16 and Comparative Examples 14 and 15, various physical properties and the bounce height and the bounce coefficient when the falling ball heights were 10 cm, 20 cm and 30 cm were measured by the methods described in the specification. Moreover, the plasticizer resistance was evaluated by the same method as in Examples 11 and 12 and Comparative Examples 10 and 11. The results are shown in Table 6.

11 Double-sided adhesive tape 12 Soft polyvinyl chloride sheet 13 Polypropylene board

Claims (18)

100 parts by mass of the acrylic polymer (X) having a weight average molecular weight of 550,000 to 1,000,000, 3 to 9 parts by mass of the tackifier resin (Y) having a softening point of 140 to 160 ° C., and a cross-linking agent (Z). A pressure-sensitive adhesive composition containing
The acrylic polymer (X) contains 60% by mass or more of the (meth) acrylic acid alkyl ester monomer (a) having 4 or less carbon atoms in the alkyl group, and 100 parts by mass of the (meth) acrylic acid alkyl ester monomer (A). A pressure-sensitive adhesive composition, which is a polymer of a monomer component containing 5 to 18 parts by mass of a carboxyl group-containing monomer (B). The pressure-sensitive adhesive composition according to claim 1, wherein the (meth) acrylic acid alkyl ester monomer (a) having 4 or less carbon atoms in the alkyl group contains n-butyl (meth) acrylate. The pressure-sensitive adhesive composition according to claim 1 or 2, wherein the carboxyl group-containing monomer (B) is acrylic acid. The pressure-sensitive adhesive composition according to any one of claims 1 to 3, wherein the pressure-sensitive adhesive resin (Y) is a rosin-based pressure-sensitive adhesive resin. The pressure-sensitive adhesive composition according to any one of claims 1 to 4, wherein the pressure-sensitive adhesive resin (Y) contains 13% by mass or less of a component having a molecular weight of 600 or less. The pressure-sensitive adhesive composition according to any one of claims 1 to 5, wherein the cross-linking agent (Z) is at least one selected from the group consisting of a metal chelate-based cross-linking agent and an isocyanate-based cross-linking agent. An adhesive tape having an adhesive layer comprising the adhesive composition according to any one of claims 1 to 6. An adhesive tape in which an adhesive layer composed of the adhesive composition according to any one of claims 1 to 6 is laminated on at least one surface of a base material. The adhesive tape according to claim 8, wherein the base material is a pulp fiber non-woven fabric containing 0.1 to 60% by mass of a rayon component. The adhesive tape according to claim 8, wherein the base material contains a thermoplastic resin and a plasticizer. The adhesive tape according to claim 10, wherein the thermoplastic resin is polyvinyl acetal. The adhesive tape according to claim 10 or 11, wherein the base material is either a non-woven fabric made of fibers containing the thermoplastic resin and a plasticizer, or a porous body having a large number of bubbles. The base material is a porous body containing a thermoplastic resin and a plasticizer and having a large number of bubbles.
The porous body has a loss coefficient of the first-order antiresonance frequency of 0.2 or more in the range of 0 to 50 ° C. measured by mechanical impedance measurement (MIM) according to ISO 16940, and 2 in the range of 0 to 30 ° C. The adhesive tape according to any one of claims 10 to 12, wherein the next antiresonance frequency is 800 Hz or less. The base material is a porous body containing polyvinyl acetal and a plasticizer and having a large number of bubbles.
The adhesive tape according to any one of claims 10 to 12, wherein the porous body has an elongation strain of 300% or more and a 50% compressive stress of 70 kPa or less. The base material is a non-woven fabric made of fibers containing polyvinyl acetal and a plasticizer.
The non-woven fabric has a coefficient of 100 to 800 g / m ² , and a non-woven fabric sample having a length of 10 cm, a width of 10 cm, and a thickness of 4 mm is placed on an iron plate having a length of 10 cm or more, a width of 10 cm or more, and a thickness of 1 cm, and has a constant falling ball height. The rebound coefficient (rebound height / falling ball height) when measuring the rebound height when a 1/2 inch SUS ball conforming to JIS B 1501 is dropped from the non-woven fabric sample toward the center is 0.1 or less. The adhesive tape according to any one of claims 10 to 12. The adhesive tape according to any one of claims 7 to 15, wherein the gel content of the pressure-sensitive adhesive layer is 30 to 50% by mass. The adhesive tape according to any one of claims 7 to 16, wherein a soft polyvinyl chloride resin is used as an adherend. The adhesive tape according to any one of claims 7 to 17, which is used for vehicle interiors.

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