JPH08209099A - Acrylic tacky adhesive composition and tacky adhesive tape - Google Patents

Abstract

PURPOSE: To obtain an acrylic tacky adhesive composition composed of a specific acrylic copolymer and a polyfunctional isocyanate compound at a specific ratio, having sufficiently balanced initial tacky adhesive properties and excellent heat-resistance, salt-water resistance and durability and useful for a tacky adhesive tape, etc. CONSTITUTION: This acrylic tacky adhesive composition is composed of (A) 100 pts.wt. of an acrylic copolymer composed of (i) a vinyl monomer free from carboxyl group and (ii) a macromonomer containing an unsaturated double bond on one terminal of the molecule and having a number-average molecular weight of 3,000-30,000 and (B) 0.3-3 pts.wt. of a polyfunctional isocyanate compound such as tolylene diisocyanate. The composition is preferably further incorporated with an acrylic polymer having hydroxyl group. A tacky adhesive tape is produced preferably by applying an adhesive layer composed of the composition to one surface of a substrate such as a soft vinyl chloride resin film containing a plasticizer and a stabilizer.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an acrylic pressure-sensitive adhesive composition, particularly a pressure-sensitive adhesive tape laminated on one side of a synthetic resin film having a metal vapor deposition layer, and a soft vinyl chloride resin containing a plasticizer and a stabilizer. The present invention relates to a pressure-sensitive adhesive tape laminated on one side of a film, and more specifically to an acrylic pressure-sensitive adhesive composition and a pressure-sensitive adhesive tape having excellent initial pressure-sensitive adhesive properties and adhesive durability.

[0002]

2. Description of the Related Art As a pressure-sensitive adhesive used for a pressure-sensitive adhesive tape or sheet having a conventional metal vapor deposition layer, an alkyl (meth) acrylate as a main component is provided with cohesive force for balancing peel strength and shear holding force. An acrylic pressure-sensitive adhesive obtained by copolymerizing about 10% by weight of a vinyl monomer having a carboxyl group such as (meth) acrylic acid as a component has been generally known.

However, the pressure-sensitive adhesive tape having a metal vapor-deposited layer obtained by laminating the above-mentioned acrylic pressure-sensitive adhesive exhibits excellent physical properties in the initial stage of application, but has poor moisture-resistant adhesiveness, particularly poor adhesiveness under exposure to salt water, There were problems such as turning over and peeling.

This mechanism is such that the metal vapor deposition layer is corroded by moisture such as moisture, particularly moisture containing ions such as sodium chloride and potassium chloride due to seawater or sea breeze,
It is known that the metal in the vapor-deposited metal layer is ionized and eluted, and the adhesive force is lowered due to the reaction between the metal ion and the carboxyl group in the pressure-sensitive adhesive.

On the other hand, the above-mentioned acrylic pressure-sensitive adhesive is also used as a decorative pressure-sensitive adhesive tape or sheet by laminating it on a soft vinyl chloride resin sheet containing various pigments, plasticizers or stabilizers. Such a decorative adhesive tape or sheet can be cut out to a desired design by a computer-controlled cutting machine and is excellent in workability, so it is used as a "pasting paint" that replaces conventional decoration by painting every year. It is popular.

However, the decorative pressure-sensitive adhesive tape obtained by laminating the above-mentioned acrylic pressure-sensitive adhesive exhibits excellent physical properties in the initial stage of application, but has poor adhesive durability, especially when adhered to a curved surface, so that floating or the like may occur. There was a problem that peeling occurred.

[0007] This mechanism is that the oxirane oxygen-containing compound such as epoxidized soybean oil and the stabilizer such as metal soap stabilizer are transferred to the pressure-sensitive adhesive layer from the soft vinyl chloride resin layer containing the plasticizer, For example, it is known that the unreacted epoxy residue in the epoxidized soybean oil reacts with the carboxyl group in the pressure-sensitive adhesive, or the metal ion in the metal soap stabilizer reacts with the carboxyl group. ing.

From the above, in the adhesive tape having a metal vapor-deposited layer or the soft vinyl chloride resin adhesive tape containing a plasticizer and a stabilizer, the problem that the adhesive is turned over or peeled off is that the carboxyl group in the adhesive is metallic. It is considered that the cause is that the pressure sensitive adhesive is modified by reacting with ions or epoxy residues.

To solve both of the above problems, by copolymerizing a polar component such as N-vinylpyrrolidone,
An acrylic pressure-sensitive adhesive using a copolymer having substantially no carboxyl group has been disclosed (JP-A-61-28).
62).

[0010]

However, when the above acrylic pressure-sensitive adhesive is used for a pressure-sensitive adhesive tape having a metal vapor deposition layer or a soft vinyl chloride resin pressure-sensitive adhesive tape containing a plasticizer and a stabilizer, the pressure-sensitive adhesive is substantially Since it does not contain a carboxyl group, there is almost no decrease in adhesive strength over time, but there is a problem that it is difficult to obtain a sufficient balance of adhesive properties in the initial stage due to insufficient adhesive strength to metal adherends and insufficient cohesive strength. was there.

The object of the present invention is to achieve a sufficient initial balance of adhesive properties, and even when used for an adhesive tape having a metal vapor deposition layer or a soft vinyl chloride resin adhesive tape,
(EN) It is intended to provide an acrylic pressure-sensitive adhesive composition and a pressure-sensitive adhesive tape that do not cause a decrease in adhesive strength due to modification of the pressure-sensitive adhesive over time.

[0012]

First, the invention "hereinafter referred to as the present invention 1" described in claim 1 will be described in detail.
The acrylic copolymer used in the present invention 1 is composed of a vinyl monomer (A) and a macromonomer (B) having no carboxyl group, and the vinyl monomer (A) having no carboxyl group has, for example, a carbon number of 1-1
Examples thereof include alkyl (meth) acrylates having an alkyl group of 4 and vinyl monomers having a polar group other than a carboxyl group.

The above-mentioned alkyl (meth) acrylate has an alkyl group having 1 to 14 carbon atoms, and examples thereof include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate and isopropyl (meth). ) Acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-
Butyl (meth) acrylate, tert-butyl (meth) acrylate, hexyl (meth) acrylate, 2
-Ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, lauryl (meth) acrylate, myristyl (meth) acrylate and the like. These may be used alone or in combination of two or more.

When the content of the alkyl (meth) acrylate is small, the cohesive force of the resulting acrylic copolymer is high, and it becomes difficult to obtain sufficient unevenness followability.
Further, when the amount is too large, the cohesive force of the acrylic copolymer becomes low and it becomes difficult to obtain a sufficient shear holding force. Therefore, in the acrylic copolymer, preferably 60 to 99% by weight, more preferably 70 to 97% by weight. %.

Examples of the vinyl monomer having a polar group other than the carboxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate and caprolactone modified (meth). ) Acrylate,
Hydroxyl group-containing vinyl monomers such as polyethylene glycol (meth) acrylate and polypropylene glycol (meth) acrylate, (meth) acrylonitrile, N-vinylpyrrolidone, N-vinylcaprolactam, N-vinyllaurylolactam, (meth) acryloylmorpholine, (meth ) Acrylamide, dimethyl (meth) acrylamide, N-methylol (meth) acrylamide, N
-Containing nitrogen such as butoxymethyl (meth) acrylamide, dimethylaminopropyl (meth) acrylamide, dimethylaminomethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, diethylaminoethyl (meth) acrylate Examples thereof include vinyl monomers, which may be used alone or in combination of two or more kinds. Further, the hydroxyl group-containing vinyl monomer is preferably used for effectively crosslinking not only the island portion but also the sea portion in the sea-island structure when the acrylic copolymer is cross-linked with the polyfunctional isocyanate compound. .

When the content of the vinyl monomer having a polar group other than the above-mentioned carboxyl group is small, the obtained acrylic copolymer has a low cohesive force, and it is difficult to obtain a sufficient shear holding force. Of the acrylic copolymer, the peel strength is lowered and the peel strength is lowered.
Is.

In the acrylic copolymer, other vinyl monomers may be copolymerized in addition to the alkyl (meth) acrylate and the vinyl monomer having a polar group other than the carboxyl group, such as vinyl acetate, Examples thereof include vinyl pivalate, vinyl propionate, styrene, and isobornyl (meth) acrylate. These may be used alone or in combination of two or more.

When the content of the vinyl monomer increases, the cohesive force increases and the peel strength decreases. Therefore, the content of the vinyl monomer in the acrylic copolymer is preferably 30% by weight or less, more preferably 10% by weight or less.

The above-mentioned macromonomer (B) has an unsaturated double bond at one terminal in the molecule and has a number average molecular weight of 3,000 to 30,000. As the double bond, for example, an acryloyl group,
Methacryloyl groups and the like are preferably mentioned, and the non-reactive main chain portion is a homopolymer or copolymer of a monofunctional vinyl monomer, and examples of the monofunctional vinyl monomer include the alkyl (meth) acrylates described above. Other examples include styrene and the like.

The macromonomer (B) is a polymer which becomes a main chain of the macromonomer in advance (hereinafter referred to as "main chain polymer").
And a vinyl group is added to the terminal.

The above-mentioned main chain polymer can be obtained by solution polymerization, bulk polymerization, suspension polymerization or the like, but solution polymerization is preferable in that a desired main chain polymer can be easily obtained. The polymerization method by the solution polymerization, for example, a reflux condenser, a thermometer,
After adding a monofunctional vinyl monomer, a chain transfer agent containing a carboxyl group, and a solvent into a reaction vessel equipped with a stirrer, a dropping funnel, and a nitrogen gas introduction tube, sufficiently stir and mix, and purge with nitrogen gas for 30 minutes. After removing the dissolved oxygen by heating, the mixture is heated to 70 ° C. Then, at 70 ° C., under nitrogen atmosphere, a thermal decomposition type radical polymerization initiator solution is added dropwise using a dropping funnel to polymerize until the reaction is completed,
A main chain polymer is obtained. Then, further glycidyl (meta)
By adding a vinyl monomer having a carboxylic acid-reactive group such as acrylate, the carboxyl group derived from the chain transfer agent at the end of the main chain polymer reacts to add a vinyl group to obtain a macromonomer.

The above chain transfer agent containing a carboxyl group is
It is added for the purpose of controlling the molecular weight of the obtained main chain polymer and introducing a carboxyl group at its end, for example,
Examples thereof include mercaptoacetic acid and mercaptopropionic acid.

Examples of the solvent used during the solution polymerization include all the solvents generally used in the solution polymerization,
Examples thereof include ethyl acetate, benzene, toluene, methyl ethyl ketone and the like.

Examples of the thermal decomposition type radical polymerization initiator include ketone peroxides such as methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide, and cyclohexanone peroxide, isobutyryl peroxide, benzoyl peroxide, 2, and the like.
Diacyl peroxides such as 4-dichlorobenzoyl peroxide and P-chlorobenzoyl peroxide, diisopropylbenzene hydroperoxide,
Hydroperoxides such as t-butyl hydroperoxide, 2,5-dimethyl-2,5-di- (t-butylperoxy) hexane, 1,3-bis- (t-butylperoxyisopropyl) benzene, Dialkyl peroxides such as di-t-butyl peroxide, 1,
Peroxyketals such as 1-di- (t-butylperoxy) -3,3,5-trimethylcyclohexane and 1,1-di- (t-butylperoxy) cyclohexane, t
-Alkyl peresters such as -butyl peroxypivalate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxyisobutyrate, di-2-ethylhexyl peroxydicarbonate, bis- (4-
In addition to organic peroxides such as percarbonates such as t-butylcyclohexyl) peroxydicarbonate,
2'-azobis-isobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis-2,4-dimethylvaleronitrile, 1,1'-azobis-1-cyclohexanecarbo Nitrile, dimethyl-
Examples of the azobis compound include 2,2'-azobisisobutyrate, 4,4'-azobis-4-cyanovaleric acid, and 2,2'-azobis- (2-aminopropane) dihydrochloride.

When the number average molecular weight of the macromonomer is small, it is difficult to obtain sufficient cohesive force, and when it is large, the solution viscosity of the acrylic copolymer becomes high, which makes it difficult to obtain productivity. 000 to 30,000
It is 0, preferably 5,000 to 25,000.

When the content of the above-mentioned macromonomer decreases, the cohesive force of the resulting acrylic copolymer decreases,
In the above acrylic copolymer, preferably 1 to 15% by weight, because sufficient shear holding force is difficult to obtain, and when it is large, cohesive force is high and sufficient peel strength is difficult to obtain.
It is more preferably 3 to 10% by weight.

The acrylic copolymer used in the present invention 1 comprises the above-mentioned copolymerizable vinyl monomer (A) and macromonomer (B), and is used for thermal polymerization such as solution polymerization, bulk polymerization and suspension polymerization, and photopolymerization. Although it can be obtained by copolymerization by polymerization or the like, the solution polymerization is preferable in that the viscosity can be arbitrarily adjusted by diluting with a solvent, and desired additives such as a tackifying resin can be uniformly mixed.

The polymerization method by the solution polymerization is, for example,
After adding the above mixed monomer, chain transfer agent and solvent into a reaction vessel equipped with a reflux condenser, a thermometer, a stirrer, a dropping funnel, and a nitrogen gas introducing tube, sufficiently stir and mix, and purge with nitrogen gas for 30 minutes. After removing the dissolved oxygen by doing so, it is heated to 70 ° C. Thereafter, the thermal decomposition type radical polymerization initiator solution is added dropwise at 70 ° C. under a nitrogen atmosphere using a dropping funnel to polymerize until the reaction is completed, whereby the above acrylic copolymer is obtained.

The above chain transfer agent is added for the purpose of suppressing variations in polymerization reaction and appropriately controlling the molecular weight. For example, n-dodecyl mercaptan, 2-mercaptoethanol, β-mercaptopropionic acid, β-mercaptopropionic acid. Octyl, methoxybutyl β-mercaptopropionate, trimethylolpropane tris (β-thiopropionate), butyl thioglycolate, propanethiols, butanethiols, thiophosphites and other thiol compounds such as carbon tetrachloride Examples thereof include halogen compounds.

Examples of the solvent and the thermal decomposition type radical polymerization initiator include the solvent and the thermal decomposition type radical polymerization initiator used for obtaining the macromonomer (B).

The acrylic pressure-sensitive adhesive composition of the present invention 1 can be obtained by adding a specific amount of a polyfunctional isocyanate compound to the acrylic copolymer obtained above.

Examples of the polyfunctional isocyanate compound include tolylene diisocyanate (TDI), tolidine diisocyanate (TODI), naphthylene-
1,5-diisocyanate, diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HMDI), isophorone diisocyanate (IPD
I), xylene diisocyanate (XDI), trimethylolpropane modified TDI, triphenylmethane triisocyanate, methylenebis (4-phenylmethane) triisocyanate, etc., and these may be used alone or in combination of two or more kinds. You may.

When the amount of the polyfunctional isocyanate compound added is small, the cohesive force is low, and it becomes difficult to obtain sufficient shear holding force. When the amount is large, the cohesive force is high and sufficient peeling strength is difficult to obtain. The amount is 0.3 to 3 parts by weight, preferably 0.5 to 2.5 parts by weight, based on 100 parts by weight of the acrylic copolymer.

The crosslink density after drying of the acrylic pressure-sensitive adhesive composition is determined as a gel fraction, and is obtained by the weight fraction of insoluble components after the acrylic pressure-sensitive adhesive after drying is sufficiently immersed in tetrahydrofuran. For the same reason as above, the gel fraction is preferably 40 to 90% by weight, more preferably 50 to 85% by weight.

If necessary, tackifier resins, plasticizers, softeners, fillers, pigments, dyes, etc. may be added to the acrylic pressure-sensitive adhesive composition as long as they do not impair the adhesive property.

The above tackifying resin is added for the purpose of improving the peel strength. For example, a rosin resin-based compound such as a rosin resin, a disproportionated rosin resin, a polymerized rosin resin, a hydrogenated rosin resin, etc. Examples of the polyhydric alcohol include esters of alcohols.
Examples include diethylene glycol, glycerin, and pentaerythritol. In addition, C5 series (aliphatic series) and C9 series
Other tackifying resins such as terpene resins, xylene resins, styrene resins and phenol-modified compounds thereof, as well as system (aromatic) petroleum resins and coumarone / indene resins can be mentioned. The above may be used alone or in combination of two or more.

When the amount of the tackifying resin added increases, it remains as an uncrosslinked component in the acrylic pressure-sensitive adhesive composition,
Since the cohesive force becomes low and it becomes difficult to obtain sufficient shear strength, the amount is preferably 30 parts by weight or less, more preferably 20 parts by weight or less, relative to 100 parts by weight of the acrylic copolymer.

Next, the invention "Claim 2" will be described in detail. The present invention 2 is characterized in that the macromonomer has a hydroxyl group, and the other detailed description is the same as the present invention 1.

The macromonomer used in the present invention 2 is
Since it has a hydroxyl group in its molecule, when the above acrylic copolymer is crosslinked with a polyfunctional isocyanate compound, the crosslinking density of the island portion in the sea-island structure due to the macromonomer is further increased, and as a result, With the improvement of cohesive force, it is added for the purpose of obtaining sufficient shear holding power at high temperature.

The above-mentioned macromonomer has a hydroxyl group in the molecule, an unsaturated double bond at one end in the molecule, and a number average molecular weight of 3,000 to 30,000. Examples of the unsaturated double bond at the terminal include, for example,
Preferable examples thereof include an acryloyl group and a methacryloyl group, and the non-reactive main chain portion is a homopolymer or copolymer of a monofunctional vinyl monomer. ) Other than acrylate, styrene and the like can be mentioned.

The macromonomer may be a mixture of a macromonomer having a hydroxyl group and a macromonomer having no hydroxyl group.

As a specific method for producing the above-mentioned macromonomer having a hydroxyl group, for example, at the time of polymerizing the main chain polymer of the macromonomer (B) used in the present invention 1, the above-mentioned vinyl monomer having a hydroxyl group is copolymerized. The hydroxyl group-containing vinyl monomer used in this case may be any of those mentioned above.

Next, the invention "Claim 3 of the Invention" described in claim 3 will be described in detail. The present invention 3 is the acrylic pressure-sensitive adhesive composition of the present invention 1 and the invention 2, further comprising a hydroxyl group in the molecule and compatible with the island portion in the sea-island structure resulting from the macromonomer. It is characterized in that a polymer is added.

The acrylic polymer used in the present invention 3 has a hydroxyl group in its molecule and is compatible with the island portion in the sea-island structure resulting from the macromonomer, and therefore the above-mentioned acrylic copolymer is used. When crosslinked with a polyfunctional isocyanate compound, the crosslinking density of the island portion in the sea-island structure due to the macromonomer further increases,
As a result, as the cohesive force is improved, it is added for the purpose of obtaining sufficient shear holding power at high temperature.

Since the acrylic polymer is compatible with the island portion in the sea-island structure resulting from the macromonomer, a polymer similar to the main chain polymer of the macromonomer is preferable. When the chain polymer has methyl methacrylate as the main component, a copolymer of a hydroxyl group-containing vinyl monomer and methyl methacrylate and the like are suitable, and the hydroxyl group-containing vinyl monomer used in this case includes all of the above.

If the amount of the acrylic polymer added is too large, it will be difficult to obtain sufficient cohesive force if the acrylic polymer remains uncrosslinked by the polyfunctional isocyanate compound.
Based on 100 parts by weight of the acrylic copolymer, it is preferably 30 parts by weight or less, more preferably 2 parts by weight in terms of solid content.
It is 0 parts by weight or less.

Next, the invention “Claim 4 of the Invention” described in claim 4 will be described in detail. The pressure-sensitive adhesive tape of the present invention 4 is obtained by laminating a pressure-sensitive adhesive layer made of the acrylic pressure-sensitive adhesive composition obtained in the present inventions 1 to 3 on a substrate.

Examples of the substrate include paper substrates such as Japanese paper, kraft paper and crepe paper, synthetic resin substrates such as polyethylene, polypropylene, polyvinyl chloride and polyester, and cloth substrates such as rayon, vinylon and cotton. All of those generally used as the base material of the adhesive tape such as a metal sheet base material can be mentioned.

The layering on the above-mentioned substrate may be carried out by coating a polyethylene terephthalate film or the like which has been subjected to a mold release treatment, followed by drying and then laminating it, or directly coating it on the substrate. However, when applied directly to paper or cloth, the smoothness of the adhesive surface is difficult to obtain due to penetration into the base material, and when applied directly to the polyvinyl chloride resin base material, it expands during drying. Therefore, since the adhesive thickness is likely to vary,
The former laminating method is preferred.

Next, the invention "Claim 5" will be described in detail. The pressure-sensitive adhesive tape of the present invention 5 is characterized in that the base material used in the present invention 4 is made of a synthetic resin film having a metal vapor deposition layer.

Examples of the constitution of the pressure-sensitive adhesive tape of the present invention 5 include 3 such as "synthetic resin film / metal vapor deposition layer / acrylic pressure-sensitive adhesive layer" and "metal vapor deposition layer / synthetic resin film / acrylic pressure-sensitive adhesive layer". In addition to a four-layer structure such as a layer structure, "synthetic resin film / metal vapor deposition layer / protective layer / acrylic adhesive layer", "protective layer / metal vapor deposition layer / synthetic resin film / acrylic adhesive layer", etc. A multilayer structure having more primer layers between layers for the purpose of enhancing the adhesion between the layers may be used. Among the configurations described above, those having a synthetic resin film or a protective layer on the metal vapor deposition layer are preferable for the purpose of protecting the metal vapor deposition layer.

Examples of the synthetic resin film include:
Films made of polyester, polyolefin, polyvinyl chloride, cellulosic resin, acrylic resin, etc., are excellent in heat resistance because they are often used especially for reflection covers of lighting equipment etc. Is preferred. In addition, for example, when the outermost layer is not a metal vapor deposition layer but a synthetic resin film, that is, incident light passes through the synthetic resin film, is reflected at the metal vapor deposition interface, and is transmitted through the synthetic resin film again to be reflected. In this case, the light transmittance is 90% so that the reflection efficiency of the metal vapor deposition layer is high.
The synthetic resin film having the above transparency is preferable.

Examples of the metal used for the metal vapor deposition layer include, for example, all metals that can be vapor-deposited generally, such as gold, silver and aluminum, and the thickness of the metal vapor deposition layer is usually sufficient. It is preferably about 1,000 angstroms in terms of obtaining high reflection efficiency.

Next, the invention "Claim 6" will be described in detail. The pressure-sensitive adhesive tape of the present invention 6 is characterized in that the base material used in the present invention 4 is made of a soft vinyl chloride resin film containing a plasticizer and a stabilizer.

The above-mentioned soft vinyl chloride resin film can be obtained by appropriately adding a plasticizer, a stabilizer and the like to the vinyl chloride polymer. Usually, a pigment that is appropriately mixed and colored is used.

Examples of the vinyl chloride-based polymer include polyvinyl chloride alone, a copolymer of vinyl chloride and vinyl acetate, a mixture of a copolymer of vinyl chloride and ethylene, and polyvinyl chloride, and the like. Examples of the plasticizer include phthalic acid plasticizers such as dioctyl phthalate and dibutyl phthalate, phosphoric acid plasticizers such as trioctyl phosphate, polyester plasticizers such as adipic acid ester, and the like. Examples of the stabilizer include metal soap-based stabilizers such as barium / zinc-based stabilizers, epoxy-based stabilizers such as epoxidized soybean oil, and the like, and each of these constituent components may be used alone,
Also, two or more kinds may be used in combination.

If necessary, a light stabilizer such as an ultraviolet absorber may be added to the soft vinyl chloride resin film containing the above-mentioned plasticizer and stabilizer.

The soft vinyl chloride resin film containing the above-mentioned plasticizer and stabilizer is obtained by heating an organosol prepared by uniformly mixing the above-mentioned respective components in a solvent into a sheet by a calendering method or a casting method, and heating and drying. The thickness is preferably 30 to 100 μm, and 50 to 7
0 μm is more preferable.

[0059]

Since the acrylic pressure-sensitive adhesive composition of the present invention does not contain any carboxyl group in its constituents, the pressure-sensitive adhesive tape provided with the dried pressure-sensitive adhesive layer on one side of the synthetic resin film having the metal vapor deposition layer. When used as, the pressure-sensitive adhesive is unlikely to be denatured or deteriorated due to the salt formation of metal ions and carboxyl groups liberated by the corrosion of the vapor-deposited metal layer due to moisture or the like, so that it does not change with time.

When used as an adhesive tape provided on one side of a soft vinyl chloride resin film containing a plasticizer and a stabilizer, an epoxy residue derived from the epoxidized soybean oil which is the stabilizer in the soft vinyl chloride resin is used. The pressure-sensitive adhesive is less likely to be denatured or deteriorated due to the reaction between the metal ion and the carboxyl group derived from the base or the metal soap-based stabilizer, and does not change with time.

Further, since the sea-island structure is formed by copolymerizing the macromonomer with the acrylic copolymer, the cohesive force is improved due to the island portion. Further, as the macromonomer, a macromonomer having a hydroxyl group may be used. Alternatively, by adding an acrylic polymer having a compatible hydroxyl group to the island portion of the macromonomer, the island portion is more strongly crosslinked by crosslinking with the polyfunctional isocyanate compound, and as a whole, a sufficient cohesive force is obtained. It becomes an adhesive having.

As a result, the degree of cross-linking in the sea part of the sea-island structure can be lowered, so that the adhesive has high flexibility at room temperature and sufficient peel strength while maintaining sufficient cohesive force. . From the above, excellent peel strength and shear retention,
Moreover, it is considered that a pressure-sensitive adhesive having excellent adhesion durability can be obtained.

[0063]

EXAMPLES Examples of the present invention will be described below. still,
Hereinafter, "part" means "part by weight". "Macromonomer" According to the composition of Table 1, methyl methacrylate (hereinafter referred to as "MMA") and butyl methacrylate were placed in a 5-neck separable flask equipped with a reflux condenser, a thermometer, a stirrer, and a nitrogen gas inlet tube. (Hereinafter "B
MA)), 2-hydroxyethylmethacrylate (hereinafter referred to as "2HEMA"), mercaptoacetic acid and ethyl acetate are added and sufficiently stirred, and then dissolved oxygen is removed by purging with nitrogen gas for 30 minutes. A solution of 0.1 part of azobisisobutyrovalerianic acid dissolved in 1 part of ethyl acetate was added dropwise with a dropping funnel in a state where the temperature was raised to 70 ° C. while stirring under a nitrogen atmosphere, and the mixture was added for 10 hours. The reaction was performed to obtain a main chain polymer of macromonomer.

Then, triethylamine (hereinafter referred to as "TE
A)) and 1 part of glycidyl methacrylate (hereinafter referred to as “GMA”) are added, and the mixture is heated under reflux for 5 hours and then cooled, and the precipitate precipitated in isopropyl alcohol at 60 ° C. After vacuum drying for 24 hours, macromonomers M1 and M2 were obtained.

As the macromonomers M3 to M7, the following commercial products manufactured by Toagosei Co., Ltd. were used. Macromonomer M3; main chain: homopolymer of MMA, terminal reactive group: methacroyl group, number average molecular weight: 6,000
0, trade name “AA-6” macromonomer M4; main chain: homopolymer of MMA, terminal reactive group: methacroyl group, number average molecular weight: 11, 4
00, trade name “AA-10” macromonomer M5; main chain: homopolymer of MMA, terminal reactive group: methacroyl group, number average molecular weight: 22.0
00, trade name “AA-20” macromonomer M6; main chain: MMA / 2HEMA = 86
/ 14 copolymer, terminal reactive group: methacroyl group,
Number average molecular weight: 7,000, trade name "AA-714S" Macromonomer M7; Main chain: BMA / 2HEMA = 93
/ 7 copolymer, end reactive group: metacroyl group, number average molecular weight: 7,000, trade name "AA-707S"

"Acrylic polymer" According to the composition of Table 1, MMA, 2H was placed in a 5-neck separable flask equipped with a reflux condenser, a thermometer, a stirrer, and a nitrogen gas inlet tube.
After adding EMA, methacrylic acid (hereinafter referred to as “MAc”), mercaptoacetic acid and ethyl acetate and thoroughly stirring,
Dissolved oxygen is removed by purging with nitrogen gas for 30 minutes, and the temperature is raised to 70 ° C while stirring in a nitrogen atmosphere.
A solution of 0.1 part of azobisisobutyrovaleric acid dissolved in 1 part of ethyl acetate was added dropwise using a dropping funnel and reacted for 10 hours to obtain acrylic polymers AP1 and AP2. As the acrylic polymer AP3, polymethylmethacrylate (manufactured by Wako Pharmaceutical Co., Ltd.) was used.

[0067]

[Table 1]

[Preparation of Acrylic Copolymer] Tables 2 to 11
In accordance with the composition of the above, in a 5-neck separable flask equipped with a reflux condenser, a thermometer, a stirrer, and a nitrogen gas inlet tube,
n-butyl acrylate (hereinafter referred to as "BA"), 2-
Ethylhexyl acrylate (hereinafter referred to as "2EHA"), 2-hydroxyethyl methacrylate (hereinafter referred to as "2H"
EMA), acrylic acid (hereinafter “AAc”), macromonomer, n-dodecyl mercaptan (hereinafter “DDM”) and ethyl acetate are added and sufficiently stirred, and then purged with nitrogen gas for 30 minutes. Then, dissolved oxygen was removed, and the temperature was raised to 70 ° C. with stirring under a nitrogen atmosphere and 0.03 parts of benzoyl peroxide was dissolved in 1 part of ethyl acetate. The mixture was dropped and reacted for 10 hours to obtain an acrylic copolymer.

However, Examples 15 to 21, 27 and 2 below
8, 43-49, 55, 56 and Comparative Examples 11-18,
In Nos. 29 to 35, an acrylic copolymer to which the above acrylic polymer was further added was obtained.

(Examples 1-28, Comparative Examples 1-18) "Preparation of pressure-sensitive adhesive tape having metal vapor deposition layer" Trimethylolpropane was added to 100 parts of the solid content of the acrylic copolymer shown in Tables 2-6. Modified TDI (solid content 55% by weight, manufactured by Nippon Polyurethane Company, trade name "Coronate L55E",
(Hereinafter referred to as "Coronate L") and uniformly mixed, and then coated on a release-treated polyethylene terephthalate film (hereinafter referred to as "PET film").
A 25 μm pressure-sensitive adhesive film was obtained by drying in an oven at 0 ° C. for 5 minutes.

Further, the pressure-sensitive adhesive tape having the metal vapor-deposited layer of the constitution 1 was obtained by laminating the pressure-sensitive adhesive film on the silver-vapor-deposited surface of the 38 μm polyester film on which the silver vapor-deposited layer having a thickness of 1000 Å was laminated. A pressure-sensitive adhesive tape of Structure 2 was obtained by laminating the above-mentioned pressure-sensitive adhesive film on the protective layer surface of the film having the protective layer on the silver vapor deposition surface of the polyester film having the layer.

The evaluation items and evaluation methods are shown below. (Measurement of gel fraction) A predetermined amount W (g) of a film having a metal vapor deposition layer or a pressure-sensitive adhesive film before being transferred to a soft vinyl chloride resin film is replaced with tetrahydrofuran (THF).
After being left at 40 ° C. for 24 hours, the weight of dried residue Wa (g) when filtered through a 200-mesh stainless steel wire net is measured, and the gel fraction is measured by the following formula:
The results are shown in Tables 2-11. Gel fraction (wt%) = 100 x (Wa / W)

(Peeling strength test) The adhesive tape having the metal vapor deposition layer was cut into a strip having a width of 20 mm, and then JIS
In accordance with Z0237, SUS plate (width 50 mm, length 1
The peel strength was measured using a test plate of 50 mm, thickness 2 mm, and product number "SUS # 304"), and the results are shown in Tables 2 to 6. The unit is gf / 20 mm.

(Shear holding power test) After cutting the pressure-sensitive adhesive tape having the metal vapor deposition layer into a strip having a width of 20 mm, an SUS plate (width 2 mm) was prepared so that the adhesive area was 20 mm × 20 mm.
5mm, length 50mm, thickness 2mm, product number "SUS # 3
04 ″) under the condition of 23 ° C., and further using a 2 kg pressure roller to make two reciprocations at a speed of 300 mm / min for sufficient bonding, and further left for 20 minutes to obtain a test piece. In the shearing direction of the test piece, a load of 1 kg was applied to measure the deviation length after 1 hour, and the results are shown in Tables 2 to 6.
It was shown to. The unit is mm.

(Heat Resistance Test) A test after cutting the adhesive tape having a metal vapor deposition layer obtained in Examples and Comparative Examples into a strip of 75 mm width, pasted on a galvanized steel sheet and left for 2 hours. Pieces were obtained, and after the pieces were allowed to stand in an atmosphere of 90 ° C. for 4 weeks, the presence or absence and the size of foaming or peeling were observed, and the results are shown in Tables 2 to 6.

(Salt water resistance test) The maximum erosion distance of the salt water from the end of the adhesive tape having the metal deposition layer was measured after the above test piece was immersed in a 5% sodium chloride aqueous solution in a thermostat at 30 ° C. for 4 hours. The results are shown in Tables 2 to 6.
The unit is mm.

[0077]

[Table 2]

[0078]

[Table 3]

[0079]

[Table 4]

[0080]

[Table 5]

[0081]

[Table 6]

(Examples 29 to 56, Comparative Examples 19 to 35) "Preparation of Soft Vinyl Chloride Resin Sheet" Degree of Polymerization 1,500
100 parts of polyvinyl chloride resin, 25 parts of adipic ester plasticizer (manufactured by Sekisui Chemical Co., Ltd., trade name "DOA"), barium / zinc stabilizer (manufactured by Katsuta Kako Co., Ltd., trade name "BZ-"
100T "2 parts, 0.5 parts of a benzotriazole-based ultraviolet absorber and 600 parts of a hydrocarbon-based solvent are cast, and the resulting organosol is cast and dried by heating to give a soft vinyl chloride resin sheet having a thickness of 50 μm. Obtained.

[Preparation of soft vinyl chloride resin adhesive tape]
Trimethylolpropane modified TDI (solid content 55% by weight, based on 100 parts solid content of the acrylic copolymer,
Product name “Coronate L55” manufactured by Nippon Polyurethane Company
E ”, hereinafter referred to as“ Coronate L ”) and uniformly mixed, and then coated on a release-treated polyethylene terephthalate film (hereinafter referred to as“ PET film ”) and heated in an oven at 110 ° C. for 5 minutes. 2 by drying
A 5 μm adhesive film was obtained. Further, the soft vinyl chloride resin sheet was laminated on the soft vinyl chloride resin sheet to obtain a soft vinyl chloride resin adhesive tape.

Evaluation items and evaluation methods are shown below. (Initial peel strength test) The soft vinyl chloride resin adhesive tape was cut into strips having a width of 20 mm, and then JIS Z02 was used.
According to 37, SUS plate (width 50 mm, length 150 m
m, thickness 2 mm, product number "SUS # 304") was used as a test plate, and the peel strength was measured. The results are shown in Tables 7 to 11. The unit is gf / 20 mm.

(Curved Surface Adhesion Test) The soft vinyl chloride resin adhesive tape was cut into a strip having a width of 25 mm, and then a width of 23
Adhesion on a curved surface was measured by sticking the aluminum plate having a width of 19 cm in the width direction and further fitting the aluminum plate into a frame having a width of 19 cm. The state after 1 hour from application was designated as "initial curved surface adhesion", and the state after being left in a constant temperature bath at 40 ° C for 2 weeks was designated as "curved surface adhesion after aging". 7-11. Evaluation Criteria ◯: No floating and no peeling. Δ: Partially lifted or edge peeling of 1 mm or more occurred. ×: Floating in a considerable portion or peeling of the end portion of 3 mm or more occurred.

[0086]

[Table 7]

[0087]

[Table 8]

[0088]

[Table 9]

[0089]

[Table 10]

[0090]

[Table 11]

[0091]

The acrylic pressure-sensitive adhesive composition of the present invention is excellent in pressure-sensitive adhesive properties, heat resistance and salt water resistance at the initial stage of application, and is used as a pressure-sensitive adhesive tape laminated on a synthetic resin film having a metal vapor deposition layer. If it is, it becomes an adhesive tape having excellent optical properties such as light reflectivity, so that it becomes an adhesive tape having a metal vapor deposition layer that can be suitably used for a reflective cover of an illumination lamp, whether indoors or outdoors. ing. Also,
When used as an adhesive tape laminated on a soft vinyl chloride resin film, there is no decrease in adhesive strength due to the transfer of the stabilizer to the adhesive, and because it is excellent in outdoor durability, vinyl chloride tape, especially It can be suitably used for decorative purposes outdoors.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location C09J 7/02 JJZ 133/06 JDC

Claims (6)

[Claims] 1. A vinyl monomer having no (A) carboxyl group and (B) having an unsaturated double bond at one terminal in the molecule and having a number average molecular weight of 3,000 to 30,000.
Acrylic copolymer 1 consisting of 0 macromonomer
00 parts by weight and a polyfunctional isocyanate compound 0.3 to
An acrylic pressure-sensitive adhesive composition comprising 3 parts by weight. 2. The acrylic pressure-sensitive adhesive composition according to claim 1, wherein the macromonomer (B) has a hydroxyl group. 3. The acrylic pressure-sensitive adhesive composition according to claim 1, further comprising a hydroxyl group-containing acrylic polymer. 4. A pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer comprising the acrylic pressure-sensitive adhesive composition according to any one of claims 1 to 3 provided on one side of a substrate. 5. The pressure-sensitive adhesive tape according to claim 4, wherein the base material is a synthetic resin film having a metal vapor deposition layer. 6. The pressure-sensitive adhesive tape according to claim 4, wherein the base material is a soft vinyl chloride resin film containing a plasticizer and a stabilizer.