JP6895051B2 - Adhesive tape for airtightness and waterproofing - Google Patents

Description

The present invention relates to an airtight waterproof adhesive tape, and more particularly to an airtight waterproof adhesive tape having excellent temporal stability as an adhesive tape even in a high temperature and high humidity environment, and further excellent adhesiveness and moisture heat resistance. Is.

Conventionally, adhesive tapes using acrylic resins have been, for example, kraft tapes, OPP (Oriented Poly Propylene) tapes, packaging tapes such as cloth adhesive tapes, cellophane adhesive tapes for light packaging, temporary fixing tapes, foaming for automobiles. Tape, anti-vibration sheet, flame-retardant adhesive tape, re-peelable double-sided tape, residential curing tape, soundproof seal, double-sided tape for fixing carpet, temporary fixing tape, vinyl tape for electrical insulation, outdoor anticorrosion tape, indoor display tape, Anti-slip tape, various masking tapes, various surface protection tapes, airtight and waterproof adhesive tapes, adhesive base materials for medical emergency adhesive plasters, surgical tapes, adhesive bandages, tapes for electrical and electronic equipment, double-sided optical tapes, surface protection It is used in a wide range of applications such as films, dicing tapes for semiconductors, heat conductive tapes, heat resistant tapes, and conductive tapes. Above all, the use of airtight and waterproof adhesive tapes is becoming popular from the viewpoint of ease of handling.

Examples of the airtight and waterproof adhesive tape are those disclosed in Patent Documents 1 and 2 below. As the pressure-sensitive adhesive composition used for these, a pressure-sensitive adhesive composition using an acrylic resin is described.

Japanese Unexamined Patent Publication No. 2006-83235 Japanese Unexamined Patent Publication No. 2001-294830

However, in the disclosure technique of Patent Document 1, a waterproof adhesive tape in which an acrylic pressure-sensitive adhesive layer is provided on at least one side of a synthetic resin film base material satisfying a specific condition has been proposed. Has not been investigated, and such adhesives are not satisfactory in terms of adhesiveness and moisture heat resistance.

In the technique disclosed in Patent Document 2, an acrylic type having a Lami adhesive strength of 1,000 g / 15 mm or more on a thermoplastic resin flat yarn base material containing a hindered phenol-based antioxidant and a phosphite-based antioxidant. Adhesive tapes for airtight waterproofing of buildings made of adhesives have been proposed, but similar to the above, such adhesives are not satisfactory in terms of adhesiveness and moisture and heat resistance.

As mentioned above, the acrylic pressure-sensitive adhesive composition is also useful as an airtight and airtight adhesive tape, and enforces the law concerning promotion of the quality of waterproof and airtight houses (houses with excellent waterproof and airtightness). , In response to energy saving due to high airtightness and high heat insulation of the house, the joints between the structure and members of the house, gaps between the members, etc. (mainly around the sash opening and the overlapping part of the moisture permeable waterproof sheet, etc. An airtight waterproof adhesive tape is used for at least one of airtightness and waterproofing. Such an airtight waterproof adhesive tape is required to adhere firmly to the adherend, to have excellent stability over time as an adhesive tape even in a high temperature and high humidity environment, and to have excellent adhesiveness and moisture heat resistance. Has been done.

Therefore, the present invention provides an airtight and waterproof adhesive tape that is excellent in stability over time as an adhesive tape even in a high temperature and high humidity environment, and is also excellent in adhesiveness and moisture heat resistance. It is the purpose.

However, as a result of diligent research in view of such circumstances, the present inventors have obtained a specific terminal carboxyl group-containing monomer as a copolymerization component constituting the acrylic resin in the airtight waterproof adhesive tape using the acrylic resin. When it is contained, by using an isocyanate-based cross-linking agent as an essential cross-linking agent, it is excellent in stability over time as an adhesive tape even in a high temperature and high humidity environment, and further excellent in adhesiveness and moisture heat resistance. The present invention has been completed by finding that it becomes a thing.

That is, the gist of the present invention is at least one (a1) selected from a (meth) acrylate having an alkyl group having 1 to 24 carbon atoms, a cyclic structure-containing monomer, and a vinyl ester-based monomer having 1 to 5 carbon atoms, the following general. An acrylic resin (A) obtained by copolymerizing a terminal carboxyl group-containing monomer (a2) represented by the formula (1) and a copolymerization component (a) containing (meth) acrylic acid (a3), and an isocyanate-based crosslink. The present invention relates to an airtight and waterproof pressure-sensitive adhesive tape, which comprises a pressure-sensitive adhesive obtained by cross-linking a pressure-sensitive adhesive composition containing the agent (B).

〔formula〕
^{_{CH 2 = CR 1 -CO-O-}} (R 2 -COO-) n H ··· (1)
(Here, R ¹ is a hydrogen or methyl group, R ² is an ethylene chain , and n is a positive number of 1 or more.)

In the present invention, as the adhesive tape for airtight waterproofing, the terminal carboxyl group-containing monomer (a2) represented by the above general formula (1) is used as a copolymerization component of the acrylic resin in order to further improve the adhesiveness. However, when the terminal carboxyl group-containing monomer (a2) is contained, isocyanate is generally used as a cross-linking agent because of its excellent adhesiveness to rough surfaces and low-polarity adherends. An epoxy-based cross-linking agent is used instead of a system-based cross-linking agent. This is because when the terminal carboxyl group-containing monomer (a2) is contained, if an isocyanate-based cross-linking agent is used, the amount of the cross-linking agent added increases in order to have holding power, and so on. This is because there is a concern that the property and the adhesiveness to the low-polarity adherend may decrease, and therefore it is difficult to achieve both the adhesiveness to the rough surface and the low-polarity adherend and the holding power. .. However, in an epoxy-based cross-linking agent, in a high-temperature and high-humidity environment, the cross-linked structure in the adhesive collapses due to the influence of moisture and the like, the gel fraction decreases with time, and the stability with time as an adhesive tape is impaired. There were problems such as cross-linking and a decrease in holding power. In the present invention, even when the terminal carboxyl group-containing monomer (a2) is used as a copolymerization component, by intentionally selecting an isocyanate-based cross-linking agent as the cross-linking agent, it can be used as an adhesive tape even in a high temperature and high humidity environment. It has been found that the adhesive tape for airtightness and waterproofing has excellent stability over time, and also has excellent adhesiveness and moisture and heat resistance.

The airtight and waterproof adhesive tape of the present invention is applied to various adherends such as high-polarity adherends such as metal and wood, low-polarity adherends, and adherends having a rough surface, including plastic materials. It has good adhesiveness, is excellent in stability over time as an adhesive tape even in a high temperature and high humidity environment, and has an effect of excellent adhesiveness and moisture heat resistance.

Further, the content ratio of the copolymerization component (a) is 1 to 98% by weight of the (meth) acrylate (a1) having an alkyl group having 1 to 24 carbon atoms, and the terminal carboxyl group represented by the general formula (1). When the content of the monomer (a2) is 1 to 20% by weight and the content of the (meth) acrylic acid (a3) is 0.1 to 5% by weight, the adhesiveness and holding power are improved.

Further, when the hydroxyl group-containing monomer (a4) is further contained as the copolymerization component (a), the adhesiveness and holding power are further improved.

When the content of the isocyanate-based cross-linking agent (B) is 0.1 to 5 parts by weight with respect to 100 parts by weight of the acrylic resin (A), the moisture resistance becomes more excellent.

Hereinafter, the present invention will be described in detail.
In the present invention, (meth) acrylic means acrylic or methacryl, (meth) acryloyl means acryloyl or methacryloyl, and (meth) acrylate means acrylate or methacrylate. The acrylic resin is a resin obtained by polymerizing a polymerization component containing at least one (meth) acrylate-based monomer.

The pressure-sensitive adhesive composition of the present invention contains an acrylic resin (A) obtained by copolymerizing a copolymerization component (a) containing a specific monomer component, and an isocyanate-based cross-linking agent (B).

<Acrylic resin (A)>
The acrylic resin (A) used in the present invention is at least one selected from (meth) acrylates having an alkyl group having 1 to 24 carbon atoms, cyclic structure-containing monomers, and vinyl ester-based monomers having 1 to 5 carbon atoms (1). It is obtained by copolymerizing a1), a terminal carboxyl group-containing monomer (a2) represented by the following general formula (1), and a copolymerization component (a) containing (meth) acrylic acid (a3).
Further, as the copolymerization component (a), a hydroxyl group-containing monomer (a4) and other polymerizable monomers (a5) are contained, if necessary. Hereinafter, each copolymerization component (a) will be described in order.

<(A1) component>
The component (a1) is at least one selected from a (meth) acrylate having an alkyl group having 1 to 24 carbon atoms, a cyclic structure-containing monomer, and a vinyl ester-based monomer having 1 to 5 carbon atoms. Of these, a (meth) acrylate having an alkyl group having 1 to 24 carbon atoms is preferable. The content ratio of (a1) is usually 1 to 98% by weight, particularly preferably 50 to 98% by weight, and more preferably 70 to 98% by weight of the entire copolymerization component (a). If the content of the component (a1) is too small, the adhesiveness tends to decrease, and if it is too large, the holding power tends to decrease.

The (meth) acrylate having an alkyl group having 1 to 24 carbon atoms in the component (a1) includes a (meth) acrylate having an alkyl group having 1 to 3 carbon atoms (a1-1) and a carbon number of carbons. It preferably contains at least one selected from (meth) acrylates (a1-2) having an alkyl group having 4 to 24, preferably 4 to 12 carbon atoms, and more preferably has an excellent balance between holding power and adhesive power. From the point of view, it contains both (meth) acrylate (a1-1) and (meth) acrylate (a1-2).

The content ratio of the (meth) acrylate (a1-1) having an alkyl group having 1 to 3 carbon atoms is 1 to 20% by weight, particularly 1 to 18% by weight, more, the total amount of the copolymerization component (a). It is preferably 2 to 15% by weight. If the content of the component (a1-1) is too small, the holding power tends to decrease, and if it is too large, the adhesiveness to a low-polarity adherend tends to decrease.

The content ratio of the (meth) acrylate (a1-2) having an alkyl group having 4 to 24 carbon atoms, preferably 4 to 12 carbon atoms is 55 to 97% by weight, particularly 70 to 97% by weight of the total copolymerization component (a). It is preferably 95% by weight, more preferably 80 to 90% by weight. If the content of (a1-2) is too small, the adhesiveness to a low-polarity adherend tends to decrease, and if it is too large, the adhesiveness tends to decrease and the holding power tends to decrease.

The (meth) acrylate (a1-2) having an alkyl group having 4 to 24 carbon atoms, preferably 4 to 12 carbon atoms is the (meth) acrylate having an alkyl group having 4 to 7 carbon atoms (a1-2-1). ), And at least one selected from (meth) acrylate (a1-2-2) having an alkyl group having 8 to 24 carbon atoms, preferably 8 to 12 carbon atoms, and preferably having high holding power and high holding power. Those containing both (meth) acrylate (a1-2-1) and (meth) acrylate (a1-2-2) from the viewpoint of excellent balance of adhesion to polar adherends and low-polarity adherends. Is.
The content ratio of the above (a1-2-1) component to the above (a1-2-2) component is (a1-2-1) / (a1-2-2) = 1/99 to 85 / by weight. 15, particularly preferably 5/95 to 80/20, more preferably 10/90 to 70/30, particularly preferably 15/85 to 40/60. If the content ratio of the above component (a1-2-1) is too small, the holding power tends to decrease, and if it is too large, the adhesiveness to a low-polarity adherend tends to decrease.

Examples of the (meth) acrylate (a1-1) having an alkyl group having 1 to 3 carbon atoms include methyl (meth) acrylate, ethyl (meth) acrylate, and propyl (meth) acrylate. Of these, methyl (meth) acrylate and ethyl (meth) acrylate are preferably used.

Examples of the (meth) acrylate (a1-2-1) having an alkyl group having 4 to 7 carbon atoms include n-butyl (meth) acrylate, iso-butyl (meth) acrylate, and tert-butyl (meth) acrylate. , N-Hexyl (meth) acrylate and the like, and among them, n-butyl (meth) acrylate is preferable because it is easily available and is excellent in economy.

Examples of the (meth) acrylate (a1-2-2) having an alkyl group having 8 to 24 carbon atoms include 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, and isononyl. (Meta) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, isotridecyl (meth) acrylate, myristyl (meth) acrylate, isomyristyl (meth) acrylate, cetyl (meth) acrylate, stearyl ( Examples thereof include meta) acrylate, isostearyl (meth) acrylate, and behenyl (meth) acrylate. Among them, (meth) acrylate having an alkyl group having 8 to 12 carbon atoms is preferable because of its low polarity and low glass transition temperature. In particular, 2-ethylhexyl (meth) acrylate is preferable.

Next, the cyclic structure-containing monomer in the component (a1) is usually an acrylic monomer substituted with a substituent having a cyclic structure, for example, N- (meth) acryloylmorpholin, N-vinylpyrrolidone, and the like. A heterocyclic-containing (meth) acrylate having a morpholine ring such as N-vinylcaprolactam, vinylpyrrolidone, N- (meth) acryloylpiperidin, N- (meth) acryloylpyrrolidine, a piperidin ring, a pyrrolidine ring, a piperazin ring, etc. , Phenyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenyldiethylene glycol (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, benzyl (meth) acrylate, dicyclo Pentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, dicyclopentanyl (meth) acrylate, nonylphenol polyethylene glycol (meth) acrylate, nonylphenoxypolyethylene glycol (meth) acrylate, isobonyl (meth) acrylate, biphenyloxy Ethyl (meth) acrylate and the like can be mentioned, and styrene, α-methylstyrene and the like can also be mentioned. Among them, a heterocyclic (meth) acrylate having a morpholine ring is preferable because it has a good balance of various physical properties, and N- (meth) acryloyl morpholine is particularly preferable from the viewpoint of easy availability and safety.

Examples of the vinyl ester-based monomer having 1 to 5 carbon atoms in the component (a1) include vinyl formate, vinyl acetate, vinyl propionate, vinyl valerate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate and the like. can give. Of these, vinyl acetate is preferably used because it is easily available.

<(A2) component>
The component (a2) is a terminal carboxyl group-containing monomer represented by the following general formula (1).

〔formula〕
^{_{CH 2 = CR 1 -CO-O-}} (R 2 -COO-) n H ··· (1)
(Here, R ¹ is a hydrogen or methyl group, R ² is an ethylene chain , and n is a positive number of 1 or more.)

The content ratio of the component (a2) is usually 1 to 20% by weight, particularly preferably 1.5 to 15% by weight, and more preferably 2 to 8.5% by weight of the entire copolymerization component (a). .. If the content ratio is too small, the adhesiveness to various adherends tends to decrease, and if the content ratio is too large, the adhesiveness to low-polarity adherends tends to decrease.

<(A3) component>
The content of the (meth) acrylic acid (a3) is usually 0.1 to 5% by weight, particularly 0.5 to 4.5% by weight, and further 1 to 4% by weight of the entire copolymerization component (a). Is preferable. If the content ratio is too small, the adhesiveness to various adherends tends to decrease, and if the content ratio is too large, the adhesiveness to low-polarity adherends tends to decrease.

The content ratio of the component (a2) and the component (a3) is a weight ratio, and the component (a3) is usually 10 to 400 parts by weight, particularly 20 to 200 parts by weight, with respect to 100 parts by weight of the component (a2). Further, it is preferably 25 to 100 parts by weight, particularly preferably 30 to 75 parts by weight. If the amount of the component (a3) is too small, the holding power tends to decrease, and if it is too large, the adhesiveness to a low-polarity adherend tends to decrease.

<(A4) component>
In the present invention, the acrylic resin (A) obtained by copolymerizing the above components (a1) to (a3) is used, but it is desirable to further copolymerize the hydroxyl group-containing monomer (a4). Examples of the hydroxyl group-containing monomer (a4) include 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 5-hydroxypentyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, and 8-hydroxyhexyl (meth) acrylate. (Meta) acrylic acid hydroxyalkyl ester such as hydroxyoctyl (meth) acrylate, caprolactone-modified monomer such as caprolactone-modified 2-hydroxyethyl (meth) acrylate, oxyalkylene-modified such as diethylene glycol (meth) acrylate and polyethylene glycol (meth) acrylate. Monomer, primary hydroxyl group-containing monomer such as 2-acryloyloxyethyl-2-hydroxyethylphthalic acid; 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-chloro2-hydroxypropyl (meth) ) Secondary hydroxyl group-containing monomer such as acrylate; A tertiary hydroxyl group-containing monomer such as 2,2-dimethyl2-hydroxyethyl (meth) acrylate can be mentioned.
Among these, a primary hydroxyl group-containing monomer is preferable in terms of excellent reactivity with a cross-linking agent, and 2-hydroxyethyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate are particularly preferable.

The hydroxyl group-containing monomer (a4) is useful because it serves as a cross-linking point when a cross-linking agent is blended, and is particularly effective in the present invention in which an isocyanate-based cross-linking agent is used as the cross-linking agent. In such a case, it is usually 0.01 to 5% by weight, particularly preferably 0.05 to 3% by weight, and more preferably 0.05 to 2% by weight of the entire copolymerization component (a). If the amount of the component (a4) is too small, the holding power tends to decrease, and if it is too large, the adhesiveness to various adherends tends to decrease.

<Other polymerizable monomers (a5)>
In the present invention, another polymerizable monomer (a5) may be used if necessary, and examples of the other polymerizable monomer (a5) include an acetoacetyl group-containing monomer, an isocyanate group-containing monomer, and a glycidyl group-containing monomer. Examples thereof include an amino group-containing monomer, a functional group-containing monomer of an amide group-containing monomer, and other copolymerizable monomers.

Examples of the acetoacetyl group-containing monomer include 2- (acetoacetoxy) ethyl (meth) acrylate and allyl acetoacetate.

Examples of the isocyanate group-containing monomer include 2-acryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, and alkylene oxide adducts thereof.

Examples of the glycidyl group-containing monomer include glycidyl (meth) acrylate and allyl glycidyl (meth) acrylate.

Examples of the amino group-containing monomer include monomers having an ethylenically unsaturated double bond and an amino group (unsubstituted or substituted amino group), and examples thereof include aminomethyl (meth) acrylate and aminoethyl (meth) acrylate. Aminoalkyl (meth) acrylates such as aminopropyl (meth) acrylate and aminoisopropyl (meth) acrylate and (meth) of N-alkylaminoalkyl such as N- (t-butyl) aminoethyl (meth) acrylate. ) Monosubstituted amino group-containing (meth) acrylic acid ester such as acrylic acid ester; (meth) acrylic acid N, N-dimethylaminoethyl, (meth) acrylic acid N, N-diethylaminoethyl, (meth) acrylic acid N, Disubstituted amino group-containing (meth) acrylic acid ester such as (meth) acrylic acid ester of N, N-dialkylaminoalkyl such as N-dimethylaminopropyl; dialkylamino such as N, N-dimethylaminopropyl (meth) acrylamide. Alkyl (meth) acrylamide, quaternized salts of these amino group-containing monomers, etc .; Amino group-containing styrenes such as p-aminostyrene; Dialkylamino groups such as 3- (dimethylamino) styrene, dimethylaminomethylstyrene, etc. Stylines having; dialkylaminoalkylvinyl ethers such as N, N-dimethylaminoethyl vinyl ether, N, N-diethylaminoethyl vinyl ether; allylamine, 4-diisopropylamino-1-butene, trans-2-butene-1,4-diamine , 2-Vinyl-4,6-diamino-1,3,5-triazine and the like.

Examples of the amide group-containing monomer include a monomer having an ethylenically unsaturated double bond and an amide group (a group having an amide bond), and examples thereof include (meth) acrylamide; N-methyl (meth) acrylamide and N-ethyl. (Meta) acrylamide, N-propyl (meth) acrylamide, N-isopropyl (meth) acrylamide, Nn-butyl (meth) acrylamide, N-isobutyl (meth) acrylamide, N-s-butyl (meth) acrylamide, N -T-Butyl (meth) acrylamide, N-hexyl (meth) acrylamide, diacetone (meth) acrylamide, N, N'-methylenebis (meth) acrylamide, N- (1,1-dimethyl-3-oxobutyl) (meth) ) N-alkyl (meth) acrylamide such as acrylamide; N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N, N-dipropyl (meth) acrylamide, N, N-diisopropyl (meth) Amide, N, N-di (n-butyl) (meth) acrylamide, N, N-diisobutyl (meth) acrylamide, N, N-di (s-butyl) (meth) acrylamide, N, N-di (t-) Butyl) (meth) acrylamide, N, N-dipentyl (meth) acrylamide, N, N-dihexyl (meth) acrylamide, N, N-diheptyl (meth) acrylamide, N, N-dioctyl (meth) acrylamide, N, N N, N-dialkyl (meth) acrylamide such as −diallyl (meth) acrylamide, N, N-ethylmethylacrylamide; dialkylaminoalkyl (meth) acrylamide such as N, N-dimethylaminopropyl (meth) acrylamide; N-vinyl Substituted amide group-containing monomers such as acetoamide, N-vinylformamide, (meth) acrylamide ethylethylene urea, (meth) acrylamide t-butyl sulfonic acid; N-methylol (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, N -Hydroxyl group-containing (meth) acrylamide such as methylolpropane (meth) acrylamide; alkoxy group-containing (meth) acrylamide such as N-methoxymethyl (meth) acrylamide and N- (n-butoxymethyl) (meth) acrylamide; these amides Examples thereof include quaternized salts of group-containing monomers.

Examples of the other copolymerizable monomer include 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, methoxydiethylene glycol (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, and methoxypolyethylene glycol (meth). Monomers containing alkoxy or oxyalkylene groups such as acrylates and polypropylene glycol-mono (meth) acrylates; acrylonitrile, methacrylonitrile, vinyl stearate, vinyl chloride, vinylidene chloride, alkyl vinyl ether, vinyl toluene, dialkyl ester of itaconic acid, Examples thereof include fumaric acid dialkyl ester, allyl alcohol, acrylic chloride, methyl vinyl ketone, allyl trimethyl ammonium chloride, and dimethyl allyl vinyl ketone.

The other polymerizable monomer (a5) is contained to the extent that the effect of the present invention is not impaired in order to adjust the physical properties according to the application.

Thus, the acrylic resin (A) is produced by polymerizing the above-mentioned components (a1) to (a3), and if necessary, the components (a4) and (a5) as copolymerization components. Each component (a1) to (a5) of (a1) to (a5) can be used alone or in combination of two or more.
In such polymerization, it is preferable to produce by solution polymerization because the acrylic resin (A) can be safely and stably produced with an arbitrary monomer composition.

In such solution polymerization, for example, the copolymerization component (a) such as (a1) to (a3) and the polymerization initiator are mixed or dropped in an organic solvent according to a conventional method, and the solution is in a reflux state or 50. It may be polymerized at ~ 98 ° C. for 0.1 to 20 hours.

Examples of such a polymerization initiator include azo-based polymerization initiators such as azobisisobutyronitrile and azobisdimethylvaleronitrile, which are ordinary radical polymerization initiators, benzoyl peroxide, lauroyl peroxide, and di-t-butyl peroxide. , Peroxide-based polymerization initiators such as cumene hydroperoxide and the like can be given as specific examples. These may be used alone or in combination of two or more.

The weight average molecular weight of the acrylic resin (A) thus obtained is usually 100,000 to 5,000,000, preferably 300,000 to 1,500,000, and particularly preferably 500,000 to 900,000. If the weight average molecular weight is too small, the durability performance tends to decrease, and if it is too large, the production tends to be difficult.

The dispersity (weight average molecular weight / number average molecular weight) of the acrylic resin (A) is preferably 20 or less, particularly preferably 15 or less, further preferably 10 or less, and particularly preferably 7 or less. preferable. If the degree of dispersion is too high, the durability performance of the pressure-sensitive adhesive layer is lowered, and foaming or the like tends to occur easily. The lower limit of the dispersity is usually 1.1 from the point of view of the manufacturing limit.

Further, the glass transition temperature (Tg) of the acrylic resin (A) is preferably −80 to 10 ° C., particularly −70 to −10 ° C., more preferably −65 to −20 ° C., and the glass transition temperature is high. If it is too high, the tack tends to be insufficient, and if it is too low, the heat resistance tends to decrease.

The weight average molecular weight of the acrylic resin (A) is the weight average molecular weight converted to the standard polystyrene molecular weight, and is high performance liquid chromatography (manufactured by Nippon Waters Co., Ltd., "Waters 2695 (main body)" and "Waters 2414 (detector)". ) ”), Column: Shodex GPC KF-806L (exclusion limit molecular weight: 2 × 10 ⁷ , separation range: 100 to 2 × 10 ⁷ , theoretical number of stages: 10,000 stages / piece, filler material: styrene-divinylbenzene) It is measured by using three series of copolymer and filler particle size (10 μm), and the same method can be used for the number average molecular weight.

The degree of dispersion of the acrylic resin (A) is determined from the weight average molecular weight and the number average molecular weight.

The glass transition temperature of the acrylic resin (A) is calculated using the Fox formula, and the glass transition temperature when the monomer constituting the acrylic resin (A) is homopolymerized is usually measured by DSC. The values described in the literature and the values described in the catalog were used.
The glass transition temperature is calculated by the following Fox formula.

Tg: Copolymer glass transition temperature (K)
Tga: Monomer A homopolymer glass transition temperature (K) Wa: Monomer A weight fraction Tgb: Monomer B homopolymer glass transition temperature (K) Wb: Monomer B weight fraction Tgn: Monomer N homo Polymer glass transition temperature (K) Wn: Weight fraction of monomer N (Wa + Wb + ... + Wn = 1)

The viscosity of the acrylic resin (A) is adjusted with a solvent or the like, and the acrylic resin (A) is subjected to coating as a solution of the acrylic resin (A). The viscosity of the acrylic resin (A) solution is preferably 500 to 20000 mPa · s, particularly preferably 1000 to 18000 mPa · s, and further preferably 2000 to 15000 mPa · s from the viewpoint of ease of handling. If the viscosity is too high, the fluidity tends to decrease and it tends to be difficult to handle, and if it is too low, the pressure-sensitive adhesive tends to be difficult to apply.

The viscosity of the acrylic resin (A) solution was measured according to the 4.5.3 rotational viscometer method of JIS K5400 (1990).

<Isocyanate-based cross-linking agent (B)>
The pressure-sensitive adhesive composition of the present invention contains an isocyanate-based cross-linking agent (B) in addition to the above-mentioned acrylic resin (A). The isocyanate-based cross-linking agent (B) reacts with the functional groups in the acrylic resin (A) to form a cross-linked structure.

The isocyanate-based cross-linking agent (B) contains at least a polyisocyanate compound. Examples of the polyisocyanate compound include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanates, and alicyclic polyisocyanates such as hydrogenated diphenylmethane diisocyanate. , And their biurets, isocyanurates, and adducts, which are reactants with low molecular weight active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil.

The isocyanate-based cross-linking agent (B) may be used alone or in combination of two or more.
Further, other cross-linking agents such as epoxy-based cross-linking agents, aziridine-based cross-linking agents, melamine-based cross-linking agents, aldehyde-based cross-linking agents, amine-based cross-linking agents, metal chelate-based cross-linking agents, etc., as long as the effects of the present invention are not impaired. May be used in combination with.

The content of the isocyanate-based cross-linking agent (B) is usually 0.1 to 5 parts by weight, particularly 0.1 to 1 part by weight, and further 0.3 by weight with respect to 100 parts by weight of the acrylic resin (A). It is preferably ~ 0.9 parts by weight. If the content is too small, the holding power tends to decrease, and if it is too large, the adhesiveness to a low-polarity adherend tends to decrease.

<Adhesive imparting agent (C)>
The tackifier (C) is used for adjusting the physical properties of the acrylic resin (A), and is preferably contained in the pressure-sensitive adhesive composition of the present invention. Examples of the tackifier (C) include rosin-based resin, terpene-based resin, xylene-based resin, phenol-based resin, kumaron-based resin, petroleum resin-based resin, and the like.
When used as an airtight and waterproof adhesive tape, a rosin-based resin, a terpene-based resin, and a xylene-based resin are preferable, and a rosin-based resin is more preferable because it has an excellent balance of physical properties.

The content of the tackifier (C) is usually 1 to 50 parts by weight, particularly 5 to 30 parts by weight, and further 5 to 20 parts by weight with respect to 100 parts by weight of the acrylic resin (A). Preferably, an appropriate amount is blended according to the required physical properties.

Further, the pressure-sensitive adhesive composition of the present invention contains resin components other than the acrylic resin (A), an acrylic monomer, a polymerization inhibitor, an antioxidant, and corrosion as other components as long as the effects of the present invention are not impaired. Various additives such as inhibitors, cross-linking accelerators, radical generators, peroxides and radical trapping agents, metal and resin particles and the like can be blended. In addition to the above, a small amount of impurities and the like contained in the raw materials for producing the constituent components of the pressure-sensitive adhesive composition may be contained.

The content of the other components is preferably 5 parts by weight or less, particularly preferably 1 part by weight or less, and further preferably 0.5 parts by weight or less with respect to 100 parts by weight of the acrylic resin (A). If the content is too large, the compatibility with the acrylic resin (A) tends to decrease, and the durability tends to decrease.

As described above, the pressure-sensitive adhesive composition of the present invention comprises an acrylic resin (A) and an isocyanate-based cross-linking agent (B), as well as a pressure-sensitive adhesive (C), an ultraviolet absorber, and an oxidation, if necessary. It may contain an inhibitor, a plasticizer, a pigment, a stabilizer, a filler and the like.
By mixing the above components, the pressure-sensitive adhesive composition of the present invention can be obtained. Further, the pressure-sensitive adhesive of the present invention can be obtained by cross-linking this pressure-sensitive adhesive composition. It is also useful to use this pressure-sensitive adhesive as a pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape of the present invention.
Specifically, the above-mentioned pressure-sensitive adhesive composition is dissolved in a solvent such as ethyl acetate, and a pressure-sensitive adhesive composition solution for coating is prepared so that the solid content concentration becomes 10 to 70%, and this solution is prepared. Can be applied to a base material and dried to form an adhesive layer of an adhesive tape.

<Adhesive tape>
The pressure-sensitive adhesive tape of the present invention contains a pressure-sensitive adhesive obtained by curing the pressure-sensitive adhesive composition as a pressure-sensitive adhesive layer.

The thickness of the pressure-sensitive adhesive layer is preferably 5 to 200 μm, particularly preferably 10 to 150 μm, and even more preferably 15 to 130 μm.
If the thickness is too thick, it tends to be difficult to apply the adhesive, and if it is too thin, sufficient adhesive strength tends not to be obtained.

The gel fraction of the pressure-sensitive adhesive layer is preferably 90% by weight or less, particularly preferably 1 to 90% by weight.
If the gel fraction is too high than the preferable range, the adhesive strength tends to decrease, and if it is too lower than the preferable range, the cohesive force tends to decrease and it tends to be difficult to obtain the desired adhesive strength.

The gel fraction is a measure of the degree of cross-linking (degree of curing), and is calculated by, for example, the following method. That is, an adhesive tape (without a separator) having an adhesive layer formed on a polymer film (for example, a polyethylene terephthalate film) as a base material is wrapped with a 200 mesh SUS wire mesh and placed in toluene at 23 ° C. The gel fraction is defined as the weight percentage of the insoluble adhesive component remaining in the wire mesh after immersion for 48 hours. However, the weight of the base material is deducted.

The adhesive strength of the pressure-sensitive adhesive layer is usually 1 to 100 N / 25 mm with respect to the adherend to be used, but among them, when a test plate of SUS304 steel plate is used as the adherend having relatively high polarity. Is a 180 ° peel strength according to JIS Z0237, preferably 25 N or more / 25 mm, particularly preferably 30 N or more / 25 mm, and further preferably 35 N or more / 25 mm. The upper limit is usually about 100 N / 25 mm.
When a polyethylene test plate is used as the adherend having a relatively low polarity, the peel strength is 180 ° according to JIS Z0237, preferably 3N or more / 25mm, and particularly preferably 5N or more / 25mm. More preferably, it is 10 N or more / 25 mm. The upper limit is usually about 100 N / 25 mm. When an OSB plate test plate is used as the adherend having a rough surface, the peel strength is 90 ° according to JIS Z0237, preferably 3N or more / 25mm, and particularly preferably 5N or more / 25mm. More preferably, it is 6 N or more / 25 mm. The upper limit is usually about 50 N / 25 mm.

The adhesive strength is not limited to the above adhesive strength range because it changes depending on the composition (material), surface condition (surface roughness), treatment (cleaning) conditions, etc. of the adherend.

The measurement of such adhesive strength is a value measured according to JIS Z0237. Specifically, it can be measured by the method described in Examples described later.

When the test piece is a double-sided adhesive tape, the adhesive surface not to be tested can be measured by covering it with a polyethylene terephthalate film having a nominal thickness of 25 (manufactured by Toray Industries, Inc., Lumirror S10) specified in JIS C2318. ..

Further, the holding force of the pressure-sensitive adhesive layer is 3.0 mm or less even if the test piece is displaced from the test plate after 24 hours, or the test piece is measured by the method described in Examples described later. Even if it falls within 24 hours, its holding time is preferably 150 min or more.

The moist heat resistance of the pressure-sensitive adhesive layer was measured by the method described in Examples below, that is, after being stored in a constant temperature and humidity chamber at 60 ° C. and 90% RH for 14 days, in a gel fraction test. , The difference from the initial gel fraction is preferably less than 10%. On the other hand, in the holding force test, the difference from the displacement width of the initial test piece is preferably less than 1 mm.

The adhesive tape of the present invention is a single-sided adhesive tape or a double-sided adhesive tape.

Further, the pressure-sensitive adhesive layers of the double-sided pressure-sensitive adhesive tape may be the same pressure-sensitive adhesive layer or may be pressure-sensitive adhesive layers having different compositions.

In the pressure-sensitive adhesive tape of the present invention, it is preferable to provide the pressure-sensitive adhesive layer on the base material from the viewpoint of handling and the like. The base material is not particularly limited as long as it is a conventionally known base material, but for example, rayon cloth, cotton cloth, polyester cloth, cloth made of a blended yarn of rayon and polyester, non-woven fabric, flat yarn cloth, and flat yarn. Examples thereof include a laminated film in which a plastic film is laminated on the cloth, and among these, those containing flat yarn cloth are preferable because of their high tensile strength in the longitudinal direction.

Flat yarn cloth is a woven fabric made by weaving a flat yarn called flat yarn, which is made by cutting a polyethylene or polypropylene film into strips and stretching it to give it strength. The intersections of the flat yarns that intersect laterally are fixed by heat fusion to prevent misalignment.

As a method for producing such an adhesive tape, a known general method for producing an adhesive tape may be used. For example, an adhesive is applied and dried on one surface of a base material, and a release liner is applied to the surface of the formed adhesive layer. It can be produced by a method of laminating the adhesive, or a method of applying and drying an adhesive on one surface of the release liner and laminating a base material, preferably a base material having hand-cutting property, on the surface of the formed pressure-sensitive adhesive layer. ..

In providing the pressure-sensitive adhesive layer on the base material, the surface of the base material having hand-cutting property is known and commonly used, for example, physical treatment such as corona discharge treatment and plasma treatment, and chemical treatment such as undercoating treatment. Surface treatment may be appropriately applied.

Examples of the release liner include a plastic film made of a polyolefin resin such as polyethylene, a polyester resin such as polyethylene terephthalate, a vinyl acetate resin, a polyimide resin, a fluorine resin, and a plastic such as cellophane; kraft paper, Japanese paper, etc. Paper; rubber sheet made of natural rubber, butyl rubber, etc .; foam sheet made by foaming polyurethane, polychloroprene rubber, etc .; metal foil such as aluminum foil, copper foil; composites thereof and the like. Further, these may be subjected to surface treatment such as corona treatment on one side or both sides thereof.

Further, as the release liner, for example, glassin paper, kraft paper, clay coated paper laminated with a film such as polyethylene, paper coated with a resin such as polyvinyl alcohol or acrylic acid ester copolymer, polyester, polypropylene and the like. Examples thereof include a synthetic resin film coated with a release agent such as a fluorine-based resin or a silicone-based resin.

Among these, a paper release liner is preferable because it is easily torn by hand, and a paper release liner having a base paper basis weight of 40 to 120 g / m ² , preferably 50 to 80 g / m ² is particularly preferable. .. Further, the thickness of the release liner is preferably 40 to 180 μm, particularly preferably 60 to 140 μm, and further preferably 80 to 120 μm. If the thickness is too thin, it tends to be difficult to manufacture, such as wrinkles during winding, and if it is too thick, the hand-cutting property tends to decrease.

When laminating the release liner on the adhesive layer of the double-sided adhesive tape, select each release liner so that the release liners laminated on both sides have different peeling forces in order to improve workability. Is preferable. For example, if the release liner on the surface side to be attached at the beginning of the double-sided adhesive tape has a lighter peeling force than the release liner on the surface side to be attached next, the workability is improved.

As the coating device used when applying the composition forming the pressure-sensitive adhesive to various sheet-like substrates, a commonly used coating device may be used, for example, a roll knife coater, a die coater, a roll coater, and a bar coater. , Gravure roll coater, reverse roll coater, dipping, blade coater, etc.

Further, under the drying conditions, the solvent and residual monomers in the pressure-sensitive adhesive are dried and removed during drying, and when a cross-linking agent is used, the functional group of the base resin reacts with the cross-linking agent to form a cross-linked structure. Any condition can be used. The drying conditions are preferably, for example, 60 to 120 ° C. for about 1 to 5 minutes. After drying, it can be aged with the pressure-sensitive adhesive layer sandwiched between sheet-like substrates, and the cross-linking reaction can be further promoted.

The adhesive tape of the present invention may be in the form of a roll, may be in a single-wafer state, or may be further processed into various shapes.
When the adhesive tape is a double-sided adhesive tape, it is preferable that release liners are provided on both surfaces of the two adhesive layers in the single-wafer state, and in the roll state, the two adhesive layers are provided. It is preferable that the release liner is provided only on one surface.

Further, the adhesive tape of the present invention preferably has a high tensile strength, and when it is attached to an aluminum sash or a wall material, it is required to have the strength required for pulling it so as not to distort it or peeling it off for position correction. The tensile strength of the adhesive tape is preferably 20 N or more / 25 mm, more preferably 30 N or more / 25 mm, and further preferably 50 N or more / 25 mm. The upper limit of the tensile strength is usually 250 N / 25 mm. To make a double-sided adhesive tape with high tensile strength, use a film whose tensile strength of the easy-to-cut film of the base film is equal to or higher than the tensile strength of the target adhesive tape. Can be achieved.

Thus, the adhesive tape of the present invention can be obtained, but the adhesive tape of the present invention does not deteriorate the adhesive performance with respect to the adherend or the base material which deteriorates the adhesive performance, and also under moist heat conditions. It has good adhesive performance. Further, when a base material having a hand-cutting property is used as the base film, it can be easily cut by hand at an arbitrary position without using a tape cutter or the like in the width direction of the tape. It will be particularly useful as an adhesive tape.

The adhesive tape of the present invention includes, for example, kraft tapes, OPP tapes, cloth adhesive tapes and other wrapping tapes, light wrapping cellophane adhesive tapes, automobile foam tapes, vibration damping sheets, flame-retardant adhesive tapes, and residential curing tapes. Soundproof seal, double-sided tape for fixing carpet, vinyl tape for electrical insulation, outdoor anticorrosion tape, tape for indoor display, anti-slip tape, adhesive tape for airtight waterproofing, adhesive base material for medical emergency adhesive plaster, surgical tape, adhesive bandage, etc. It can be used in a wide range of applications such as tapes for electrical and electronic equipment, double-sided tapes for optics, dicing tapes for semiconductors, heat conductive tapes, heat-resistant tapes, conductive tapes, etc. is there.

The adherend using the adhesive tape of the present invention is not particularly limited, but a suitable adherend when used as an airtight and waterproof adhesive tape is, for example, a housing structure or the like. Examples include members and gaps between members. Among them, an adherend having a relatively high polarity such as an aluminum sash, an adherend having a relatively low polarity such as a moisture-permeable waterproof sheet, an adherend having a rough surface such as an OSB plate, and the like can be mentioned. .. As a specific method of using the airtight waterproof adhesive tape, for example, the airtight waterproof adhesive tape is attached to an opening such as a window to attach a sash frame, or the outer peripheral edge of the sash frame is attached. It is possible to improve the airtightness and heat insulation of houses.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples as long as the gist of the present invention is not exceeded. In the example, "part" and "%" mean the weight standard.

First, various acrylic resins (A) were prepared as follows.
The weight average molecular weight, dispersity, glass transition temperature, and viscosity of the acrylic resin (A) were measured according to the above-mentioned method.

<Acrylic resin (A)>
Prior to the production of the acrylic resin (A), the following copolymer components (a) used in the production were prepared.
(A1) As an ingredient
・ MA: Methyl acrylate ・ EA: Ethyl acrylate ・ BA: Butyl acrylate ・ 2EHA: 2-Ethylhexyl acrylate ・ Vac: Vinyl acetate ・ ACMO: Acryloylmorpholin (a2) As a component
-Terminal containing a terminal carboxyl group represented by the following general formula (1) CH ₂ = CR ^1- CO-O- (R ^2- COO-) _n H ... (1)
In the above general formula (1), R ¹ is hydrogen, R ² is an ethylene chain, and n is a compound (a3) component of 1 to 5.
-As an acrylic acid (a4) component
HEMA: 2-Hydroxyethyl methacrylate

As the component (a2), "Sypomer H" manufactured by Solvay Nikka Co., Ltd. was used.
^{In the cypomer H, R 1} of the general formula (1) is hydrogen, R ² is an ethylene chain, and contains n = 0, that is, 25% of acrylic acid (a3) and 75% of the compound (a2) of n = 1-5. Is a mixture of

[Manufacturing of acrylic resin (A-1)]
In a reactor equipped with a thermometer, a stirrer and a reflux cooler, 6 parts of methyl acrylate (a1), 25.8 parts of butyl acrylate (a1), 63.1 parts of 2-ethylhexyl acrylate (a1), Cypomer H 5 [3.75 parts of terminal carboxyl group-containing monomer (a2) represented by the general formula (1), 1.25 parts of acrylic acid (a3)], 0.1 part of 2-hydroxyethyl methacrylate (a4), 55 parts of ethyl acetate Parts and 0.15 part of azobisisobutyronitrile as a polymerization initiator were charged, the temperature was raised with stirring, polymerization was carried out at the ethyl acetate reflux temperature for 7 hours, and then diluted with ethyl acetate to form an acrylic resin ( A 50% solution of A-1) was obtained.
The weight average molecular weight (Mw) of the obtained acrylic resin (A-1) is 580,000, the dispersity is 5.2, the glass transition temperature is -59 ° C, and the viscosity of the resin solution is 4,200 mPa · s / 25 ° C. there were.

[Manufacturing of acrylic resins (A-2) to (A-5)]
In the production of the acrylic resin (A-1), the same procedure was carried out except that the blending amount was changed to that shown in Table 1 below, to obtain solutions of the acrylic resins (A-2) to (A-5).

<Crosslinking agent>
The following were prepared as cross-linking agents.
-Isocyanate-based cross-linking agent (B): Coronate L-55E (solid content 55%) manufactured by Nippon Polyurethane Industry Co., Ltd.
-Epoxy-based cross-linking agent: 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane (manufactured by Mitsubishi Gas Chemical Company, Tetrad C)

<Adhesive imparting agent>
The following was prepared as the tackifier (C).
・ Disproportionated rosin ester (manufactured by Arakawa Chemical Industry Co., Ltd., Super Ester A-100)

<Examples 1 to 7>
With respect to the acrylic resins (A-1) to (A-5) prepared and prepared as described above, the isocyanate-based cross-linking agent (B) was converted into a solid content as a cross-linking agent with respect to 100 parts of the solid content. The amount shown in Table 2 below and 15 parts of the tackifier (C) are mixed, the solution is adjusted with ethyl acetate so that the solid content concentration becomes 48%, and the mixture is stirred until uniform, and the pressure-sensitive adhesive is used. A composition solution was obtained.
With respect to the obtained pressure-sensitive adhesive composition, a pressure-sensitive adhesive tape was prepared as follows, and the following evaluation was performed. The evaluation results are shown in Table 2 below.

<Comparative example 1>
In Example 1, the same procedure was carried out except that the epoxy-based cross-linking agent was changed to 0.033 parts with respect to 100 parts of the solid content of the acrylic resin (A-1) as the cross-linking agent to obtain a pressure-sensitive adhesive composition solution. It was.
With respect to the obtained pressure-sensitive adhesive composition, a pressure-sensitive adhesive tape was prepared in the same manner as in Example 1, and the same evaluation was performed. The evaluation results are shown in Table 2 below.

[Making an airtight waterproof adhesive tape]
The pressure-sensitive adhesive composition solution prepared as described above is applied to a flat yarn (manufactured by Diatex, thickness 130 μm) using an applicator so that the thickness after drying is 100 μm, and the pressure is 90 ° C. for 3 minutes. After drying, the peeled surface of a paper release liner (manufactured by Sun A. Kaken Co., Ltd., K-80HS (F)) was bonded. Then, a heat aging treatment was carried out in a dryer at 40 ° C. for 7 days to prepare an adhesive tape.

<Adhesiveness evaluation (1): 180 ° peel strength>
The adhesive tape was cut into a width of 25 mm and a length of 150 mm to prepare a test piece. Next, a SUS304 steel plate and a test plate of a Tyvek house wrap sheet were used as an adherend, and the test piece was crimped to this test plate by reciprocating a roller weighing 2 kg once at a crimping speed of 5 mm / s. .. After crimping, leave it for 5 minutes, fold back the play part of the test piece by 180 °, peel it off by 30 mm, fix the test plate to the lower chuck and the end of the test piece to the upper chuck, and peel it off at an angle of 180 °. The adhesive tape was peeled off from the adherend at a speed of 300 mm / min, and the adhesive strength was measured.
For the SUS304 steel sheet, a JIS standard compliant product manufactured by Engineering Test Service Co., Ltd. was used, and for the Tyvek house wrap sheet, a commercially available Tyvek (R) house wrap was used.

<Adhesiveness evaluation (2): 90 ° peel strength>
The adhesive tape was cut into a width of 25 mm and a length of 150 mm to prepare a test piece. Next, a commercially available test plate of SUS304 steel plate, aluminum plate, polyethylene plate, and OSB plate was used as an adherend, and the test piece was pressed against the surface of the test plate with a roller weighing 2 kg and a pressure of 10 mm / s. It was crimped by reciprocating twice. After crimping, leave it for 24 hours, fold back the play part of the test piece by 180 °, peel it off by 30 mm, fix the test plate to the jig, fix the end of the test piece to the chuck of the testing machine, and peel it off at an angle of 90 °. The adhesive tape was peeled off from the adherend at a speed of 300 mm / min, and the adhesive strength was measured.
For the aluminum plate, model number A1050P obtained from Japan Test Panel Co., Ltd. was used, and for the polyethylene plate, a standard test plate obtained from Japan Test Panel Co., Ltd. was used. Further, as the OSB board (Oriented Strand Board: a wood board in which thin pieces of wood were oriented and laminated and compressed at high temperature with an adhesive), a wood board manufactured by Ainsworth of Canada was used.

<Holding power>
The adhesive tape was cut into a width of 25 mm and a length of 150 mm to prepare a test piece. Next, a SUS304 steel plate test plate is used as an adherend, and a roller weighing 2 kg is crimped onto the test plate so that the contact area between the test piece and the test plate is 25 mm in width × 25 mm in length. It was crimped by reciprocating twice at a speed of 10 mm / s. The part of the test piece where the adhesive was exposed was folded back. After crimping, the mixture was left in an environment of 23 ° C. and 50% RH for 30 minutes, transferred to an environment of 40 ° C., and allowed to stand for 20 minutes. A 1 kg weight was attached so that the test plate and the test piece hang vertically, and then the time for the test piece to fall in an environment of 40 ° C. or the distance at which the test piece was displaced from the test plate was measured 24 hours later.

<Gel fraction>
The gel fraction is a measure of the degree of cross-linking (degree of curing) and was calculated by the following method.
That is, an adhesive sheet (without a separator) in which an adhesive layer is formed on a polymer sheet (polyethylene terephthalate film) as a base material is wrapped with a 200 mesh SUS wire mesh, and is contained in toluene at 23 ° C. × 24. The gel fraction was defined as the weight percentage of the insoluble adhesive component remaining in the wire mesh after immersion for a long time. However, the weight of the base material is deducted.

<Moisture and heat resistance by tape storage test>
The adhesive tape was stored in a constant temperature and humidity chamber kept at 60 ° C. and 90% RH, and the gel fraction, holding power, and appearance were evaluated every predetermined number of days.
<Gel fraction>
The gel fraction was measured by the method described above 7 days and 14 days after the start of storage.
<Holding power>
The holding power was measured 7 days and 14 days after the start of storage. The distance at which the test pieces of the above method were displaced was measured by the same method except that the distance was changed after 24 hours to 1 hour.
<appearance>
Visually, it was confirmed whether the adhesive was dripping from the side of the tape.
○ ・ ・ ・ Adhesive was not dripping × ・ ・ ・ Adhesive was dripping

From the results in Table 2 above, all of the examples of the present invention are excellent in the results of the moisture resistance test, excellent in stability over time as an adhesive tape even in a high temperature and high humidity environment, and further adhesiveness and moisture resistance. It turned out to be excellent.
On the other hand, as a result of the moisture and heat resistance test, it was found that the product of Comparative Example 1 had a remarkable decrease in gel fraction and holding power, and was clearly in a state where the adhesive was dripping, and was weak in moisture and heat resistance. ..

The airtight waterproof adhesive tape of the present invention is excellent in stability over time as an adhesive tape even in a high temperature and high humidity environment, and is also excellent in adhesiveness and moisture heat resistance, and is highly expected.

Claims (6)

At least one selected from (meth) acrylates having an alkyl group having 1 to 24 carbon atoms, a cyclic structure-containing monomer, and a vinyl ester-based monomer having 1 to 5 carbon atoms,
The terminal carboxyl group-containing monomer (a2) represented by the following general formula (1),
And (meth) acrylic acid (a3),
It is characterized by comprising an acrylic resin (A) obtained by copolymerizing a copolymerization component (a) containing the above, and a pressure-sensitive adhesive obtained by cross-linking a pressure-sensitive adhesive composition containing an isocyanate-based cross-linking agent (B). Adhesive tape for airtight and waterproof.
〔formula〕
^{_{CH 2 = CR 1 -CO-O-}} (R 2 -COO-) n H ··· (1)
(Here, R ¹ is a hydrogen or methyl group, R ² is an ethylene chain , and n is a positive number of 1 or more.) The content ratio of the copolymerization component (a) is 1 to 98% by weight of the (meth) acrylate (a1) having an alkyl group having 1 to 24 carbon atoms, and the terminal carboxyl group-containing monomer represented by the general formula (1). The airtight waterproof adhesive tape according to claim 1, wherein (a2) is 1 to 20% by weight, and the above (meth) acrylic acid (a3) is 0.1 to 5% by weight. The airtight waterproof adhesive tape according to claim 1 or 2, further containing a hydroxyl group-containing monomer (a4) as the copolymerization component (a). Any one of claims 1 to 3, wherein the content of the isocyanate-based cross-linking agent (B) is 0.1 to 5 parts by weight with respect to 100 parts by weight of the acrylic resin (A). Adhesive tape for airtightness and waterproofing described in. Any of claims 1 to 4, wherein the pressure-sensitive adhesive composition further contains 1 to 50 parts by weight of the pressure-sensitive adhesive (C) with respect to 100 parts by weight of the acrylic resin (A). Adhesive tape for airtightness and waterproofing described in item 1. The airtightness according to any one of claims 1 to 5, wherein the copolymerization component (a) contains a (meth) acrylate (a1-1) having an alkyl group having 1 to 3 carbon atoms. Adhesive tape for waterproofing.