JPH111670A - Pressure-sensitive adhesive article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a pressure-sensitive adhesive article provided with a pressure-sensitive adhesive layer having such transparency as to be adaptable to a transparent base material, and excellent in the balance between the cohesive power and the tack and in punchability. SOLUTION: This article has a (meth)acrylic pressure-sensitive adhesive layer at least on one side of a supporting base, wherein the pressure-sensitive adhesive layer has a haze value (%) of at most 30, with the haze value (%) when immersed in methanol at room temperature for 1 hr being greater than the original haze value by at least 3, and/or a islands-in-sea constitution can be recognized when the pressure-sensitive adhesive layer is observed with a transmission electron microscope.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-sensitive adhesive product, and more particularly, to a pressure-sensitive adhesive layer having excellent balance between cohesive force and pressure-sensitive adhesiveness, excellent punching, and having transparency that can be applied to a transparent substrate. The present invention relates to an adhesive product provided with:

[0002]

2. Description of the Related Art Acrylic pressure-sensitive adhesives have excellent adhesive properties such as tackiness, adhesive strength, and cohesive strength, and excellent heat resistance, weather resistance, water resistance, and oil resistance. Widely used for adhesive products. Among them, the adhesive strength and the cohesive strength are mutually contradictory physical properties. For example, when the cohesive strength is improved by, for example, increasing the crosslink density, the adhesive strength is reduced, and the adhesive strength is increased. It was very difficult to balance the cohesive and cohesive forces so that if the molecular design was designed to lower the glass transition temperature of the main polymer, cohesive failure would occur without being able to withstand deformation. . In the case of sticky products such as labels, when punching a label from an adhesive label stock, in order to cleanly punch the adhesive layer and reduce dirt on the punching blade, increase the crosslink density of the adhesive layer, It was necessary to increase the glass transition temperature of the polymer in the agent layer. However, such adhesives generally have low adhesive strength, and often do not exhibit sufficient adhesiveness, especially at low temperatures.

[0003] As such an improvement method, there have been many studies in recent years which have been studied from the viewpoint of polymer alloys using methods such as graft polymers and block polymers.
In the study on the graft copolymer, for example,
JP-A-324438, JP-A-8-143847,
JP-A-8-2090999 proposes a resin composition for an adhesive obtained by a radical copolymerization method using a macromonomer. In the study on the block copolymer, JP-A-2-103277 and JP-A-3-103277
JP-A-2500833 and JP-A-5-43857 propose a resin composition for an adhesive. JP-A-8-165462 and JP-A-9-77837 disclose, as a method for obtaining a graft polymer or a block polymer used for a resin composition for an adhesive, a simple method containing an alkyl (meth) acrylate. A method has been proposed in which a monomer mixture is polymerized in the presence of another polymer that is incompatible with the polymer of the monomer mixture.

However, the above graft polymer,
The block polymer is a segment of each polymer chain,
For example, in the graft polymer, the composition, glass transition temperature and molecular weight of the polymer main chain and the graft chain are described. In the block polymer, the refractive index is not mentioned at all. In order to maintain a high balance between cohesive strength and adhesive strength of such a graft polymer or block polymer, the adhesive polymer part is usually made to have a high molecular weight, and the polymer part that improves cohesive strength is made of glass. It is common practice to provide a glass transition temperature difference using a polymer having a high transition temperature. As a result, both polymers have a problem of reduced compatibility and become opaque, and are not suitable for transparent substrates such as polyethylene terephthalate (PET) and polyvinyl chloride (PVC). Further, even when the adhesive is used for an opaque base material, when the adhesive is attached to a transparent body such as glass, the adhesive is visible from the back side, and if the adhesive is opaque, the appearance is inferior.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has excellent balance between cohesive force and adhesive force, excellent punching, and transparency which can be applied to a transparent substrate. It is an object to provide an adhesive product provided with an adhesive layer.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, completed the present invention described below. (1) A pressure-sensitive adhesive product having a (meth) acrylic pressure-sensitive adhesive layer on at least one surface of a support substrate, wherein the pressure-sensitive adhesive layer has a haze value (%) of 30 or less and is dissolved in methanol at room temperature. A pressure-sensitive adhesive product wherein the haze value (%) when impregnated for 1 hour is 3 or more larger than the original haze value (%).

(2) At least one surface of the supporting substrate is (meta)
A pressure-sensitive adhesive product having an acrylic pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive layer has a haze value (%) of 30 or less, and a sea-island structure can be confirmed when the pressure-sensitive adhesive layer is observed with a transmission electron microscope. An adhesive product characterized by being a product. (3) The pressure-sensitive adhesive layer contains two or more polymer portions having different glass transition temperatures, and at least one glass transition temperature of another polymer portion is lower than the glass transition temperature of the polymer portion (B) having the lowest glass transition temperature. The pressure-sensitive adhesive product according to (1) or (2), wherein the temperature is higher by 15 ° C. or more and the difference in refractive index between the polymer portion (B) and all other polymer portions is ± 0.05 or less.

(4) The adhesive product according to (3), wherein the polymer part (B) having the lowest glass transition temperature has a weight average molecular weight of 10 × 10 ⁴ or more. (5) The pressure-sensitive adhesive layer contains two or more polymer parts having different glass transition temperatures, and at least one polymer part is polymerized from a monomer unit in the presence of at least one other polymer part. (1) The adhesive product according to any one of (1) to (4).

According to the present invention, it is possible to obtain a pressure-sensitive adhesive product having a transparent pressure-sensitive adhesive layer which is excellent in balance between cohesive force and adhesive force and excellent in punching, and can be applied to a transparent substrate.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The haze value (H) in the present invention indicates the ratio of diffuse light (D) to total light transmittance (T) when visible light is applied to an adhesive layer. =
It is represented by D / T. For details, see Japanese Industrial Standards (JIS
K 7105). Generally, it can be easily measured with a commercially available turbidimeter. For example, a turbidity meter (Model NDH-300A) manufactured by Nippon Denshoku Industries Co., Ltd. may be used.

In the measurement of the haze value, first, when the substrate or the support which has not been subjected to the adhesive treatment is a transparent substrate, only the substrate or the support is measured and used as a control, that is, a zero point correction. Then, the pressure-sensitive adhesive product having the pressure-sensitive adhesive layer to be measured is measured as it is. This value is used as an initial haze value. Next, the haze value after the solvent treatment may be measured as follows. Only the non-adhesive substrate or support in methanol contained in a quartz glass cell is immersed parallel to the transparent surface of the cell to which the measuring light beam strikes, and zero-corrected. Next, the adhesive product is put in this quartz glass cell, immersed at room temperature for 1 hour, and the haze value is measured in the same manner. This value is defined as the haze value after the solvent treatment.

On the other hand, when the substrate or support of the pressure-sensitive adhesive product is not transparent, the haze value of the pressure-sensitive adhesive layer may be measured as follows. First, zero point correction is performed using the transparent substrate to be transferred (good because the PET film is solvent-resistant) as a control. Next, the pressure-sensitive adhesive product is immersed in methanol to swell the pressure-sensitive adhesive layer, and is easily peeled off from the substrate or the support, and is transferred to a transparent substrate. After the transfer, the haze value is measured after evaporating the solvent. This is the initial haze value.

Next, the haze value of the adhesive product transferred to the transparent substrate is measured in a solvent in the same manner as the adhesive product of the transparent substrate. At this time, the adhesive layer may be sandwiched using two transparent substrates so that the adhesive layer does not peel off from the transparent substrate. However, it is necessary to perform zero point correction by superposing two substrates to be transferred. The observation with a transmission electron microscope in the present invention means that an adhesive polymer at room temperature is solidified with an epoxy resin, and cooled with liquid nitrogen,
A very thin slice obtained by a microtome is placed on a metal mesh for observation with a transmission electron microscope, and observation is performed after appropriate processing. Even if the polymer has a sea-island structure, the contrast may not be clear if the refractive index of the polymer in the sea part is close to that of the polymer in the island part, but the difference from the uniform polymer is usually observable. It is. If necessary, the functional groups can be dyed and observed.

The refractive index in the present invention indicates a calculated value obtained by an ordinary method. Calculated values can be calculated using the following equation _{nD AB = C A nD A +} C B nD B. In the formula, nD _AB indicates a refractive index of a copolymer obtained by copolymerizing the A monomer and the B monomer, C _A and C _B indicate weight fractions in the monomer composition, and n _{D A} and n _{D B} are The refractive index of the homopolymer of the corresponding monomer is shown. Specific examples of the refractive index of the homopolymer include polyacrylic acid (1.527),
Polymethyl acrylate (1.472), polyethyl acrylate (1.4885), n-butyl polyacrylate (1.466), polymethyl methacrylate (1.49)
0), polyethyl methacrylate (1.485), polyisobutyl methacrylate (1.477), poly (N-vinyl-2-pyrrolidone) (1.530), and polystyrene (1.590). See "POLYMER
HANDBOOK, second Edition, J. Brandrup and EH Im
mergut, Ed., JOHN WILEY & SONS, NEW YORK 1975.

Glass transition temperature (Tg) in the present invention
Indicates a calculated value or an actually measured value obtained by an ordinary method. Calculated values, the following equation (1 / Tg) = (W 1 / Tg 1) + (W 2 / Tg 2) + ··
- + can be calculated using the (W _n / Tg _n). In the formula, Tg indicates a glass transition temperature (K), W ₁ , W ₂ ,..., W _n indicates a weight fraction in the monomer composition, and Tg ₁ , Tg ₂ ,.
·, Tg _n represents a glass transition temperature of the homopolymer of the corresponding monomers (K). The glass transition temperature of the homopolymer may be a value described in a publication such as a copybook or a handbook. Specific examples of the glass transition temperature of the homopolymer include polyacrylic acid (3
79K), polymethyl acrylate (281K), polyethyl acrylate (251K), poly-n-butyl acrylate (219K), 2-ethylhexyl polyacrylate (203K), polymethacrylic acid (501K), polymethacrylic acid Methyl (378K), polyethyl methacrylate (338K), poly-n-butyl methacrylate (293
K), polyvinyl acetate (305K), polystyrene (3
73K), polyacrylonitrile (398K) and poly (N-vinyl-2-pyrrolidone) (448K).

The adhesive product of the present invention will be described in detail. The pressure-sensitive adhesive layer of the pressure-sensitive adhesive product of the present invention has a so-called sea-island structure (microdomain structure). The sea-island structure may be confirmed by observing with a transmission electron microscope, and the haze value (%) when the pressure-sensitive adhesive layer is immersed in methanol at room temperature is 3 or more larger than the original haze value (%). May be confirmed. The refractive index of methanol (20 ° C.) is 1.326, and the refractive index of (meth) acrylic polymer (for example, polymethyl acrylate (1.472), polyethyl acrylate (1.4684), polyacrylic acid) significantly lower than n-butyl (1.466)). Further, the solubility parameter of methanol (δ: (MPa) ^1/2 )
Is 29.7, and the solubility parameter of the (meth) acrylic polymer (for example, polymethyl acrylate (1
9.8), polyethyl acrylate (19.2), n-butyl polyacrylate (18.0), isobutyl polyacrylate (18.4), polymethyl methacrylate (18.
6), much higher than polyethyl methacrylate (18.3), polybutyl methacrylate (17.8), polybutyl methacrylate (16.8), etc., because methanol is an alkyl (meth) acrylate This indicates that the polymer is difficult to dissolve. That is, the (meth) acrylic acid alkyl ester-based polymer swells a little even when immersed in methanol. Even if the pressure-sensitive adhesive layer (polymer) is transparent in the dry state, if the polymer has a sea-island structure, immersion in methanol results in a different swelling rate of methanol for the sea-island structure of the sea and the island. It is considered that the amount of methanol slightly present in the portion changes, the difference in refractive index between the sea and the island increases, and the cloudiness increases, that is, the haze value increases. Solvents other than methanol that can be used to confirm the sea-island structure include alcohols other than methanol (such as isopropanol), aliphatic hydrocarbons (such as n-hexane), and alicyclic hydrocarbons (such as cyclohexane). The measurement of the haze value when a solvent other than methanol is used can be performed in the same manner as when methanol is used. In the case of isopropanol, the haze value (%) is 3 or more, and in the case of cyclohexane, the haze value (%) is 1 or more than the original haze value, whereby the sea-island structure can be confirmed.

The smaller the size of the islands in the sea-island structure is, the more preferable it is, specifically, it is preferably 1 μm or less.
More preferably, it is 5 μm or less. In order for the pressure-sensitive adhesive layer to have a sea-island structure, a polymer containing two or more kinds of incompatible polymers as a blend or a polymer containing two or more kinds of polymer chains that are incompatible with each other (graft polymer or block polymer) Should be included. Usually, a polymer or a polymer chain having the lowest glass transition temperature (hereinafter, collectively referred to as a “polymer portion”) becomes a sea and exhibits adhesive force, and the remaining polymer portion becomes an island and exhibits cohesive force. Therefore, in order to improve the balance between adhesive strength and cohesive strength, the adhesive layer contains two or more types of polymer portions having different glass transition temperatures, and the polymer portion having the lowest glass transition temperature (the polymer portion constituting the sea)
Than other polymer parts (polymer parts that make up islands)
It is preferable that at least one glass transition temperature is higher by 15 ° C. or more. It is more preferably at least 30 ° C., even more preferably at least 60 ° C.

In order for the island to work effectively as a physical cross-linking agent for the sea, the polymer constituting the pressure-sensitive adhesive layer should contain a graft polymer or a block polymer, rather than a mere blend. Is preferred. This is because a chemical bond can be formed between the sea and the island by including the graft polymer or the block polymer. The pressure-sensitive adhesive layer of the pressure-sensitive adhesive product of the present invention is a so-called transparent layer having a haze value (%) of 30 or less. The haze value (%) is preferably 20 or less, more preferably 10 or less. In order to form a transparent pressure-sensitive adhesive layer, the difference in the refractive index between the sea and the island may be reduced so that light does not bend at the interface between the sea and the island. Specifically, the difference in the refractive index between the polymer portion having the lowest glass transition temperature (polymer portion forming the sea) and all other polymer portions (polymer portion forming the islands) is ± 0.05 or less. Preferably, ±
It is more preferably at most 0.04, more preferably at most ± 0.03.

The pressure-sensitive adhesive layer of the pressure-sensitive adhesive product of the present invention is a (meth) acrylic pressure-sensitive adhesive layer. The (meth) acrylic pressure-sensitive adhesive layer means that 5% by weight or more of a monomer component constituting a polymer contained in the pressure-sensitive adhesive layer is a (meth) acrylate monomer. As described below, the polymer portion (B) having the lower glass transition temperature usually contains a large amount of a (meth) acrylic acid alkyl ester-based monomer.

The polymer portion (B) having the lower glass transition temperature is obtained by polymerizing the monomer composition (b). The monomer composition (b) preferably contains a (meth) acrylic acid alkyl ester-based monomer. The alkyl (meth) acrylate-based monomer contained in the monomer composition (b) has an alkyl group having 1 to 12 carbon atoms.
For example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, cyclohexyl (meth) acrylate, 2- (meth) acrylate Ethylhexyl, n-octyl (meth) acrylate, (meth)
Examples include alkyl (meth) acrylates such as isooctyl acrylate, dodecyl (meth) acrylate, and stearyl (meth) acrylate. One or more of these can be used. Based on the balance between tack and adhesive strength, the glass transition temperature after polymerization is
It is preferable to use one or more of those having a temperature of 80 ° C to 50 ° C in combination. Even if the glass transition temperature is high and there is no tack at room temperature, by using a far-infrared lamp or the like, tack is developed due to a rise in the temperature of the surface of the pressure-sensitive adhesive, and bonding becomes possible. Monomer composition (b)
The content of the (meth) acrylic acid alkyl ester monomer therein is preferably 70 to 99.9% by weight.
When the content of the (meth) acrylic acid alkyl ester-based monomer in the monomer composition (b) is less than 70% by weight, desired tackiness cannot be obtained, and when the content exceeds 99.9% by weight, aggregation occurs. It is not preferable because the power is insufficient.

The monomer composition (b) may optionally contain a monomer selected from unsaturated monomers having a functional group. The unsaturated monomer having the above functional group is not particularly limited. For example, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic anhydride, and maleic acid, (meth) acrylamide, N -Unsaturated amides such as methylol acrylamide and 2-hydroxyethyl (meth) acrylate,
2-hydroxypropyl (meth) acrylate, (meth)
Hydroxy group-containing polymerizable monomers such as polycaprolactone modified product of 2-hydroxyethyl acrylate (trade name: Praxel F series (manufactured by Daicel Chemical Industries, Ltd.)). One or more of these can be used. The amount of the polymerizable monomer having a functional group in the monomer composition (b) is 0.1 to 10% by weight. If the amount is less than 0.1% by weight, the crosslinking point becomes insufficient, so that the crosslinking density is not sufficient and the cohesive force is insufficient.
If the amount is more than 10% by weight, the crosslink density becomes too high or the cohesive force becomes too high, so that the adhesive strength and the resilience resistance decrease.

The monomer composition (b) may contain other polymerizable monomers which can be copolymerized, and such polymerizable monomers are not particularly limited. For example, styrene, α -Aromatic unsaturated monomers such as methylstyrene; vinyl esters such as vinyl acetate and vinyl propionate; N-containing unsaturated monomers such as N-vinylpyrrolidone and acryloylmorpholine; unsaturated nitriles such as (meth) acrylonitrile; ) Unsaturated amides such as acrylamide and N-methylolacrylamide, etc., are not particularly limited. These other monomers may be used alone,
Two or more types may be conveniently mixed.

The weight average molecular weight (G) of the polymer part (B)
(PC measurement value: standard polystyrene equivalent) is preferably 10 × 10 ⁴ or more, more preferably 20 × 10 ⁴ or more. If the weight average molecular weight is less than 10 × 10 ⁴ , the cohesive strength will be insufficient. As the polymer portion (A) having a higher glass transition temperature, those having a glass transition temperature of 0 ° C or higher are preferable, and those having a glass transition temperature of 30 ° C or higher are more preferable. When the glass transition temperature is less than 0 ° C., the pressure-sensitive adhesive layer does not have a sufficient cohesive force, and when the pressure-sensitive adhesive product is applied to soft PVC, the cohesive force is greatly reduced when the plasticizer is transferred from the soft PVC.

As the polymer portion (A), (meth) acrylic acid alkyl ester, (meth) acrylic acid, and other copolymerizable monomers (containing a functional group) may be used. For example, styrene, vinyl acetate, Acrylonitrile, methacrylonitrile, methyl methacrylate and the like can be mentioned. It can be easily obtained by radically polymerizing at least one unsaturated monomer selected from these groups by a bulk polymerization method, a solution polymerization method, or a suspension polymerization method. In addition, a commercially available thermoplastic resin that dissolves in an organic solvent used in the production of an ordinary (meth) acrylic polymer, for example, ethyl acetate, toluene, or the like can also be used. As the commercially available thermoplastic resin, for example, polystyrene, poly (acrylonitrile-styrene), polymethyl methacrylate, polyvinyl acetate and the like can be used.

The weight average molecular weight (M) of the polymer part (A)
w) is preferably 2 × 10 ⁴ or more, more preferably 5 × 10 ⁴ or more. If the weight average molecular weight is less than 2 × 10 ⁴ , when the adhesive product is used for soft PVC, the cohesive force due to the plasticizer and metal stabilizer contained in the soft PVC may be greatly reduced, which is not preferable. . In order to produce the pressure-sensitive adhesive product of the present invention, as described above, there is a difference in glass transition temperature as a condition for improving the balance between adhesion and cohesion, as being incompatible as a condition for forming a sea-island structure. The composition of the polymer portions (A) and (B) or the combination of both may be determined in consideration of the fact that the difference in the refractive index is small as a condition for being transparent, and other necessary characteristics. .

Polymer part (A) and polymer part (B)
(A) / (B) is 45/55 to 1/9
9 (parts by weight) is preferable, and more preferably 30 / parts by weight.
70 to 5/95 (parts by weight). 55 polymer parts
When the amount is less than the weight part, the adhesive properties are reduced. Also, 9
If the amount is more than 9 parts by weight, the punching workability is reduced. The method for producing the pressure-sensitive adhesive composition for producing the pressure-sensitive adhesive layer of the pressure-sensitive adhesive product of the present invention is not particularly limited, and may be a method such as a graft polymerization method using a macromer. The method of polymerizing the monomer composition (b) in the presence of the polymer (A) as described in JP-A-9-77837 and JP-A-9-77837 is preferable. According to this method, the desired pressure-sensitive adhesive layer containing the graft polymer or the block polymer and having the desired sea-island structure can be easily obtained at low cost.

As a method for polymerizing the monomer composition (b) in the presence of the polymer (A), various conventionally known methods can be employed, and are not particularly limited. For example, a solution polymerization method or a bulk polymerization method can be used. Among them, the solution polymerization method is industrially preferable. By using the solution polymerization method, it is easy to remove the heat of polymerization during the polymerization, and the workability is improved.

Specific examples of the solvent used in the solution polymerization include aromatic hydrocarbons such as toluene and xylene; aliphatic esters such as ethyl acetate and butyl acetate;
Examples thereof include alicyclic hydrocarbons such as cyclohexane; and aliphatic hydrocarbons such as hexane and pentane, but are not particularly limited as long as the polymerization reaction is not inhibited. These solvents may be used alone,
Two or more types may be conveniently mixed and used. The amount of the solvent used is not particularly limited.

The reaction conditions such as the reaction temperature and the reaction time are, for example, the composition of the monomer composition (b), the polymerization method,
What is necessary is just to set conveniently according to the physical property desired for the obtained polymer (B), the use of an adhesive composition, etc., and it is not specifically limited. Also, the reaction pressure is not particularly limited, and may be any of normal pressure (atmospheric pressure), reduced pressure, and increased pressure. Note that the polymerization reaction is desirably performed in an atmosphere of an inert gas such as a nitrogen gas.

Examples of the radical polymerization initiator include organic peroxide-based and azo-based polymerization initiators. In particular, since the organic peroxide-based polymerization initiator generates a larger amount of radicals that cause a hydrogen abstraction reaction of the polymer main chain than the azo-based polymerization initiator, the radical is derived from the monomer component from the polymer (A). In order to grow the (meth) acrylic polymer portion, it is preferable to use an organic peroxide-based polymerization initiator. As a result, the ratio of the graft polymer or the block polymer can be increased. Examples of such an organic peroxide-based polymerization initiator include benzoyl peroxide, di-tert-butyl peroxide, cumene hydroperoxide,
tert-butyl peroxide benzoate and the like.

When the polymerization of the polymer (B) is carried out under ordinary conditions, almost no block polymer is formed and a large amount of graft polymer is formed. When it is desired to produce a large number of block polymers, the polymerization of the polymer (A) is carried out in the presence of a polyvalent mercaptan such as pentaerythritol tetrakisthioglycolate, and then the monomer composition ( The polymerization of b) may be performed.

The weight average molecular weight of the graft polymer and block polymer obtained by this method is 15 × 10 ⁴
It is preferably at least 20 × 10 ⁴ . If the weight average molecular weight is too small, not only the cohesive strength after the transfer of the plasticizer is significantly reduced, but also the initial adhesive strength may be small. The pressure-sensitive adhesive composition reacts with a functional group contained in the polymer (A) and / or the component (B), that is, a functional group introduced into the molecule by another monomer having the functional group, if necessary. The resulting crosslinking agent may further be included. By using a crosslinking agent, the adhesive strength and cohesive strength of the pressure-sensitive adhesive composition can be further improved. Examples of the cross-linking agent include a polyfunctional epoxy compound, a polyfunctional melamine compound, a polyfunctional isocyanate compound, a metal cross-linking agent, an aziridine compound, and the like. The reaction of the polymer (A) and / or (B) component The compound is not particularly limited as long as it is a compound having two or more functional groups per molecule capable of reacting with the acidic functional group.

The polyfunctional epoxy compound is not particularly limited as long as it has two or more epoxy groups per molecule. Specifically, for example, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether , 1,6-hexanediol diglycidyl ether, bisphenol A / epichlorohydrin type epoxy resin, N, N, N ', N'-tetraglycidyl-m-xylenediamine, 1,3-bis (N, N-diglycidylamino Methyl) cyclohexane, N, N-diglycidylaniline, N, N-diglycidyltoluidine and the like.

The polyfunctional melamine compound is not particularly limited as long as it is a compound having two or more functional groups of one of a methylol group, an alkoxymethyl group and an imino group per molecule. For example, hexamethoxymethylmelamine, hexaethoxymethylmelamine, hexapropoxymethylmelamine, hexabutoxymethylmelamine, hexapentyloxymethylmelamine and the like can be mentioned.

As the polyfunctional isocyanate compound, 1
The compound is not particularly limited as long as it is a compound having two or more isocyanate groups per molecule. Specifically, for example, tolylene diisocyanate (TDI), 4,4'-
Isocyanate compounds such as diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate, xylylene diisocyanate, meta-xylylene diisocyanate, 1,5-naphthalene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylylene diisocyanate, and isophorone diisocyanate; Bullet polyisocyanate compounds such as Sumidur N (manufactured by Sumitomo Bayer Urethane Co.); having an isocyanurate ring such as Desmodur IL, HL (manufactured by Bayer AG) and Coronate EH (manufactured by Nippon Polyurethane Industry Co., Ltd.) Polyisocyanate compound; adduct polyisocyanate compound such as Sumidur L (manufactured by Sumitomo Bayer Urethane Co., Ltd.), coronate It can be mentioned (Nippon Polyurethane Co., Ltd.) such as adduct polyisocyanate compounds such as. These can be used alone or in combination of two or more. Also, blocked isocyanates in which the isocyanate groups of these polyvalent isocyanate compounds have been inactivated by reacting with a masking agent having active hydrogen can be used.

The metal crosslinking agent is not particularly limited, but specific examples thereof include aluminum, zinc, cadmium, nickel, cobalt, copper, calcium, barium, titanium, manganese, iron, lead, and zirconium. Metal chelate compounds in which acetylacetone, methyl acetoacetate, ethyl acetoacetate, ethyl lactate, methyl salicylate, and the like are coordinated with metals such as chromium, tin, and the like.

The aziridine compound includes N, N'-hexamethylene-1,6-bis (1-aziridinecarboxamide), trimethylolpropane-tri-β-aziridinylpropionate, bisisophthaloyl-1 -(2-methylaziridine), tri-1-aziridinyl phosphoxide, N, N'-diphenylethane-4,4'-bis (1-
Aziridine carboxamide) and the like.

The amount of the cross-linking agent used depends on the amount of the polymer (A) and / or
Or 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, per 100 parts by weight of component (B). If the amount of the crosslinking agent is less than 0.1 part by weight, the crosslinking point becomes insufficient, so that the crosslinking density is not sufficient and the cohesive force is insufficient.
If the amount exceeds 0 parts by weight, the crosslinking density becomes too high, and the adhesive strength decreases. The polymer (A) and / or (B)
The method for adding the crosslinking agent to the components is not particularly limited.

The pressure-sensitive adhesive composition may optionally contain a tackifier commonly used in pressure-sensitive adhesives. Examples of the tackifier include (polymerized) rosin type, (polymerized) rosin ester type, terpene type, terpene phenol type, cumarone type, coumarone indene type, styrene resin type, xylene resin type, phenol resin type, petroleum resin type, etc. Is mentioned.
These can be used alone or in combination of two or more.
The amount of these tackifiers to be added to the total of the above-mentioned polymers (A) and (B) is not particularly limited, but the total amount of the polymers (A) and (B) is preferably 100%.
For example, the range of 5 parts by weight to 100 parts by weight is preferable, and the range of 10 parts by weight to 50 parts by weight is more preferable. If the amount of the tackifier is less than 5 parts by weight based on the total of the above components (A) and (B), the adhesion to the adherend may not be improved. On the other hand, if the addition amount of the tackifier is more than 100 parts by weight, the tackiness may decrease and the adhesive strength may decrease, which is not preferable.

In the pressure-sensitive adhesive composition, in addition to the tackifier, conventionally known fillers, pigments, diluents, antioxidants, ultraviolet absorbers, ultraviolet stabilizers and the like which are usually used for the pressure-sensitive adhesive may be used. Can be blended. These additives may be used alone or in a combination of two or more. Further, the amounts of these additives to be added are not particularly limited and may be set conveniently so as to obtain desired physical properties.

The pressure-sensitive adhesive product of the present invention can be manufactured by forming a pressure-sensitive adhesive layer having a thickness of about 5 to 3000 μm on a substrate using the pressure-sensitive adhesive composition having the above-described structure. The adhesive product includes all known adhesive products, and examples thereof include various adhesive products such as an adhesive sheet, an adhesive label, an adhesive tape, and a double-sided tape. As the base material of the adhesive product, conventionally known papers such as high-quality paper, kraft paper, crepe paper, and glassine paper; plastics such as polyethylene, polypropylene, polyester, polystyrene, polyethylene terephthalate, polyvinyl chloride, and cellophane; Cloth, non-woven fabric, etc. can be used. The shape of the substrate includes, for example, a film shape, a sheet shape, a tape shape, and a plate shape, but is not particularly limited. An adhesive product such as an adhesive sheet, tape, or label can be obtained by applying the adhesive composition to one surface of the substrate, or a single-layer structure by applying the adhesive composition to release paper or the like, or A double-sided tape can be manufactured by applying a pressure-sensitive adhesive composition to both surfaces of the base material.

A method of applying the pressure-sensitive adhesive composition to a substrate,
That is, the method for producing the pressure-sensitive adhesive product is not particularly limited, and various known methods can be employed. For example, a method in which the pressure-sensitive adhesive composition is directly applied to a substrate; a method in which the pressure-sensitive adhesive composition is applied to release paper, and then the coated material is transferred to the substrate; The pressure-sensitive adhesive composition can be easily applied to a substrate. The application equipment used when applying the pressure-sensitive adhesive composition to the substrate is not particularly limited. Then, after applying the pressure-sensitive adhesive composition to one or both surfaces of the substrate, the substrate and the pressure-sensitive adhesive composition are integrated by drying, and a pressure-sensitive adhesive layer (hereinafter referred to as a pressure-sensitive adhesive surface) is formed on the substrate surface. ) Is formed. The drying temperature is not particularly limited. At the time of drying, for example, the functional group of the (meth) acrylic polymer reacts with the functional group of the crosslinking agent to form a crosslinked structure. In some applications, the pressure-sensitive adhesive composition may be directly applied to an adherend. Further, after the pressure-sensitive adhesive composition is applied to release paper, the coated product is peeled from the release paper, whereby the pressure-sensitive adhesive composition itself is formed into a film, sheet, tape, or plate shape. Can be manufactured.

On the pressure-sensitive adhesive surface formed on the base material surface, for example, a release sheet (release paper) formed by applying a known release agent
Should be stuck. Thereby, this adhesive surface can be suitably protected and preserved. The release sheet is peeled off from the adhesive surface when using the adhesive product. When a pressure-sensitive adhesive surface is formed on one surface of a base material such as a sheet or a tape, a known release agent is applied to the back surface of the base material (that is, the back surface of the pressure-sensitive adhesive surface). A release agent layer (hereinafter, referred to as a release agent surface) may be formed. In this case, the adhesive surface and the release agent surface are adhered by winding the base material into a roll with the adhesive surface inside, and the adhesive surface is protected and preserved.

The adhesive product of the present invention may be used as an adhesive label tape for frozen foods, an adhesive label tape having a thick adhesive layer applied to a rough surface (for floor display), an adhesive product for graphic arts (for bottles). Adhesive labels, price labels, measurement labels, nameplate labels, barcode labels,
Labels for electrical wiring, labels for copy paper, adhesive labels for home delivery, adhesive labels for business forms, adhesive films for show windows, adhesive films for signboards, mark / stripe tapes for two and four wheels, marking films, adhesives for signs Sheets, printed laminate films, surface protection, tampering prevention labels, coupon labels, wet tissue labels, linerless labels, tire display labels / stickers (windows, vehicles, storefronts)
Etc.).

Further, as a use for each base material, transparent film base materials include soft polyvinyl chloride, hard polyvinyl chloride, polypropylene, polyethylene, cellophane acetate, polyester, nylon, vinylon, etc.
Other base materials include synthetic paper.

[0046]

EXAMPLES Specific examples of the present invention will be described below together with comparative examples, but the present invention is not limited to the following examples. Unless otherwise specified, “parts” and “%” in the following Examples and Comparative Examples represent “parts by weight” and “% by weight”, respectively. Moreover, the adhesive strength test of the adhesive composition was performed according to the following method according to JISZ0237. [Method of preparing test piece] Polyethylene terephthalate as a substrate (manufactured by Toray Industries, Inc., thickness 50 μm;
T film), the pressure-sensitive adhesive composition was applied to a thickness after drying of 25 μm, and then the pressure-sensitive adhesive composition was applied to 10
By drying at 0 ° C. for 3 minutes, an adhesive surface was formed. Next, a release paper (trade name: K-80HS, manufactured by Kaken Kogyo Co., Ltd.) is adhered to the surface of the pressure-sensitive adhesive to protect the PET film, and then the PET film is kept at 23 ° C. and 65% relative humidity for 7 days. By curing, an adhesive film (adhesive product) was obtained. Then, a test piece was prepared by cutting the adhesive film into a predetermined size. The release paper was peeled off from the adhesive surface when performing various measurements.
The test piece of the PET film was used for haze value measurement, retention force measurement, and adhesion measurement.

Further, a soft polyvinyl chloride base material (hereinafter referred to as PV)
C) is applied to the release paper so that the thickness of the pressure-sensitive adhesive composition after drying is 25 μm,
After drying similarly, a PVC substrate (Mitsubishi Kasei Vinyl Co., Ltd .: # 380, thickness 0.1 mm) was transferred. Thereafter, curing was performed in the same manner as with the PET substrate. The PVC film substrate was used for measuring adhesive strength. [Measurement method of holding force] In an atmosphere of a temperature of 23 ° C and a relative humidity of 65%, a stainless steel plate (SUS304: hereafter SUS)
Adhesive board having an area of 25 mm x 25 mm, and 80 ° C 25 minutes after the application.
, And the time required to fall after applying a load of 1 kg after 20 minutes or the displacement after 24 hours was measured. [Measurement Method of Adhesive Strength] (Initial adhesive strength: PET film, PVC film) Under an atmosphere of a temperature of 23 ° C. and a relative humidity of 65%, S as an adherend was
A 2 mm tape-shaped test piece with a width of 25 mm was placed on a US plate.
A rubber roller was reciprocated three times on the test piece to attach the test piece. Twenty-five minutes after the application, the strength of the test piece when one end was peeled off at a speed of 300 mm / min in the direction of 180 ° was measured, and this was defined as the initial adhesive strength. (After heat treatment: PVC film) A PVC film test piece was heat-treated at 70 ° C for 7 days, and then left for 1 hour in an atmosphere at a temperature of 23 ° C and a relative humidity of 65%. Next, a tape-shaped test piece having a width of 25 mm was weighed 2 on a SUS plate as an adherend.
A rubber roller of kg was applied by reciprocating three times on the test piece. Twenty-five minutes after the application, the strength of the test piece when one end was peeled off at a speed of 300 mm / min in the direction of 180 ° was measured, and this was defined as the adhesive strength after the heat treatment. [Method of measuring punching workability] Temperature 23 ° C, relative humidity 6
A test piece (adhesive film) prepared in a 5% atmosphere was cut into a square having a side of 25 mm, and ten pieces were superimposed and then attached to the center of a glass plate having a side of 50 mm, and another glass plate was placed from above. I put it. Next, 5
It was left for 1 day with a load of kg. The load was removed, and the extent of protrusion of the pressure-sensitive adhesive layer was observed with a microscope. The symbols in the table indicate the following results.

○: no protruding of the pressure-sensitive adhesive layer △: slight protruding of the pressure-sensitive adhesive layer ×: protruding of the pressure-sensitive adhesive layer [Method of measuring haze value] Turbidity manufactured by Nippon Denshoku Industries Co., Ltd. according to JIS K7105. Degree meter (Model NDH-300
It measured using A). [Production of Composition for Adhesive]-Example 1-225 parts of methyl methacrylate, 2-hydroxymethacrylate in a four-necked flask equipped with a thermometer, a stirrer, an inert gas inlet tube, a reflux condenser, and a dropping funnel. 75 parts of 250 parts of a polymerizable unsaturated monomer composed of 25 parts of ethyl and 50 parts of ethyl acetate were added, and the temperature was raised to 80 ° C., and when the temperature reached 80 ° C., an azo-based initiator (trade name: ABN-V: Nippon Hydrazine Industry ( (Manufactured by Co., Ltd.) was added to initiate polymerization. Fifteen minutes after the start of the polymerization, 175 parts of the remaining polymerizable monomer, 0.438 part of ABN-V, and 120 parts of ethyl acetate were added over 1 hour, and the mixture was reacted for 4 hours. 85 parts and 4 parts of ethyl acetate were added, and the reaction was further continued for 4 hours. At the end of the polymerization, 413 parts of ethyl acetate were added. As a result, solid content 2
7.1%, viscosity 190 mPa · s (25 ° C., B-type viscometer, the same applies hereinafter), weight average molecular weight 8.9 × 10 ⁴ (GP
A methacrylic copolymer solution (C measurement: standard polystyrene conversion) was obtained. This (meth) acrylic copolymer solution is designated as A1. The refractive index (calculated value) of this (meth) acrylic copolymer is 1.4922.

Next, the above (meth) acrylic polymer solution A1 was placed in a four-necked flask equipped with a thermometer, a stirrer, an inert gas inlet tube, a reflux condenser, and a dropping funnel.
After adding 2 parts by weight, 400 parts of a polymerizable unsaturated monomer composed of 399.2 parts of n-butyl acrylate and 0.8 part of 2-hydroxyethyl acrylate, and 139.1 parts of ethyl acetate, the temperature was raised to 80 ° C. When it became, a peroxide-based initiator (trade name: BMT-K40: manufactured by NOF Corporation) was added to 0.1 wt.
The polymerization was started by adding 96 parts. After 4 hours from the start of the polymerization, 153.3 parts of ethyl acetate was further added, and after further 2 hours of reaction, the azo polymerization initiator (trade name: ABN-E: manufactured by Nippon Hydrazine Industry Co., Ltd.) was added at 0%. .4 parts and ethyl acetate 2 parts were added, and the reaction was further continued for 4 hours. At the end of the polymerization, add 302.8 ethyl acetate.
Parts were added. As a result, the solid content was 34.3% and the viscosity was 659.
An acrylic copolymer solution having a pressure of 0 mPa · s (25 ° C., B-type viscometer, the same applies hereinafter) and a weight average molecular weight of 51.3 × 10 ⁴ (GPC measurement: standard polystyrene conversion) was obtained. This (meth) acrylic copolymer solution is designated as B1.

Next, with respect to 100 parts by weight of the (meth) acrylic copolymer solution (B1), 0.35% of coronate L55E (polyisocyanate compound manufactured by Nippon Polyurethane Co., Ltd .: 55% solids) was used as a crosslinking agent. The resulting mixture was partially mixed to prepare a pressure-sensitive adhesive composition. The pressure-sensitive adhesive strength test of the obtained pressure-sensitive adhesive composition was performed according to the method described above. Table 2 shows the results. -Examples 2 to 5-A (meth) acrylic polymer was obtained by performing the reaction and operation according to Example 1 except that the reaction raw materials and / or reaction conditions were changed as shown in Table 1. Physical properties were measured using the same method as in 1. Table 2 summarizes the main reaction conditions / production conditions and results.

[0051]

[Table 1]

[0052]

[Table 2]

Example 6 The (meth) acrylic polymer solution A2 obtained in Example 2 was placed in a four-necked flask equipped with a thermometer, a stirrer, an inert gas inlet tube, a reflux condenser, and a dropping funnel. A flask was charged with 353.4 parts by weight, 2.6 parts by weight of ethyl acetate, 20 parts of n-butyl acrylate, and 25 parts of a first-stage polymerizable unsaturated monomer comprising 5 parts of acrylic acid. The mixture was stirred under a nitrogen stream and kept at 80 ° C., and Niper BMT- was used as a polymerization initiator.
Polymerization was started by adding 0.23 parts of K40 (organic peroxide manufactured by NOF Corporation).

Two hours after the reaction, the second-stage polymerizable unsaturated monomer consists of 329.2 parts of n-butyl acrylate, 0.8 parts of 2-hydroxyethyl acrylate, and 45 parts of N-vinylpyrrolidone. 375 parts of polymerizable unsaturated monomer, 156 parts of ethyl acetate and Niper BMT-K40 1.1
3 parts were continuously added dropwise over 1.5 hours, and 173 parts of ethyl acetate was added after completion of the addition. After reacting for another 2 hours,
Add 1.5 parts of ABN-E and 50 parts of ethyl acetate, and add 85 parts.
C. for 5 hours. After the reaction was completed, 110 parts of toluene was added, and the solid content was 39.5% and the viscosity was 22960 mPa · s.
s, an acrylic copolymer solution having a weight average molecular weight of 64.2 × 10 ⁴ (GPC measurement: standard polystyrene conversion) was obtained. This (meth) acrylic copolymer solution is referred to as B6.

Next, with respect to 100 parts by weight of the above (meth) acrylic copolymer solution (B6), 0.35 of coronate L55E (a polyisocyanate compound manufactured by Nippon Polyurethane Co., solid content: 55%) was used as a crosslinking agent. The resulting mixture was partially mixed to prepare a pressure-sensitive adhesive composition. The pressure-sensitive adhesive strength test of the obtained pressure-sensitive adhesive composition was performed according to the method described above. Table 4 shows the results. -Examples 7 to 8-An acrylic polymer was obtained by performing the reaction and operation according to Example 6 except that the reaction raw materials and / or the reaction conditions were changed as shown in Table 3, and the same as in Example 1. The physical properties were measured using the methods described above. Table 4 summarizes the main reaction conditions / production conditions and results. -Example 9-100 parts of polymethyl methacrylate (SUMIPEX MM: manufactured by Sumitomo Chemical Co., Ltd.) in a four-necked flask equipped with a thermometer, a stirrer, an inert gas inlet tube, a reflux condenser and a dropping funnel, ethyl acetate 266 parts were charged, and polymethyl methacrylate was dissolved in ethyl acetate. Next, 25 parts of a first-stage polymerizable unsaturated monomer consisting of 20 parts of n-butyl acrylate and 5 parts of acrylic acid was charged into the flask. The mixture was stirred under a nitrogen stream and kept at 80 ° C., and 0.23 parts of Niper BMT-K40 (organic peroxide manufactured by NOF Corporation) was added as a polymerization initiator to start polymerization.

Two hours after the reaction, the second-stage polymerizable unsaturated monomer comprises 329.2 parts of n-butyl acrylate, 0.8 parts of 2-hydroxyethyl acrylate, and 45 parts of N-vinylpyrrolidone. 375 parts of polymerizable unsaturated monomer, 156 parts of ethyl acetate and Niper BMT-K40 1.1
3 parts were continuously added dropwise over 1.5 hours, and 173 parts of ethyl acetate was added after completion of the addition. After reacting for another 2 hours,
Add 1.5 parts of ABN-E and 50 parts of ethyl acetate, and add 85 parts.
C. for 5 hours, and after the reaction was completed, 217 parts of toluene was added, and the solid content was 36.3% and the viscosity was 27760 mPa · s.
s, an acrylic copolymer solution having a weight average molecular weight of 61.3 × 10 ⁴ (GPC measurement: standard polystyrene conversion) was obtained. This (meth) acrylic copolymer solution is designated as B9.

Next, with respect to 100 parts by weight of the above (meth) acrylic copolymer solution (B9), 0.50 of coronate L55E (polyisocyanate compound manufactured by Nippon Polyurethane Co., Ltd., solid content: 55%) was used as a crosslinking agent. The resulting mixture was partially mixed to prepare a pressure-sensitive adhesive composition. The pressure-sensitive adhesive strength test of the obtained pressure-sensitive adhesive composition was performed according to the method described above. Table 4 shows the results. -Example 10-An acrylic polymer was obtained by performing a reaction and operation according to Example 9 except that the reaction raw materials and / or reaction conditions were changed as shown in Table 3, and a method similar to that in Example 1 was used. Was used to measure the physical properties. Table 4 summarizes the main reaction conditions / production conditions and results.

[0058]

[Table 3]

[0059]

[Table 4]

-Comparative Examples 1 to 3-An acrylic polymer was obtained by carrying out the reaction and operation according to Example 9 except that the reaction raw materials and / or reaction conditions were changed as shown in Table 5. Physical properties were measured using the same method as in 1. Table 6 summarizes the main reaction conditions / production conditions and results.

[0061]

[Table 5]

[0062]

[Table 6]

Each of the pressure-sensitive adhesive products of the examples has an excellent balance between the pressure-sensitive adhesive force and the cohesive force, excellent punching workability, and sufficient transparency. 1 and 2 show transmission electron micrographs of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive product of Example 10. The bar scale in FIG. 1 is 1 μm, and the bar scale in FIG.
0 nm. As shown in FIGS. 1 and 2, since the difference in refractive index between the polymer portion of the island portion and the polymer portion of the sea portion is small, the sea-island structure can be confirmed although the contrast is low.

Since the pressure-sensitive adhesive layers of the pressure-sensitive adhesive products of Comparative Examples 1 and 2 have a large difference in refractive index between the sea and the island, they are opaque with a considerably high initial haze value. 3 and 4 show transmission electron micrographs of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive product of Comparative Example 2. The bar scale in FIG. 3 is 1 μm, and the bar scale in FIG.
0 nm. As shown in FIGS. 3 and 4, since the refractive index difference between the polymer portion of the island portion and the polymer portion of the sea portion is large, the contrast is clear and the sea-island structure can be clearly confirmed.

Since the pressure-sensitive adhesive layer of the pressure-sensitive adhesive product of Comparative Example 3 has a uniform structure, it is inferior in cohesive strength and punching workability. When the pressure-sensitive adhesive layer of the pressure-sensitive adhesive product of Comparative Example 3 was observed with a transmission electron microscope, nothing was observed because of the uniform structure.

[0066]

The pressure-sensitive adhesive layer of the pressure-sensitive adhesive product of the present invention is excellent in balance between cohesive force and pressure-sensitive adhesiveness, punching workability, and has sufficient transparency. Therefore, the present invention is applicable even when the base material of the adhesive product is a transparent base material, and is excellent in aesthetics when viewed from the back side even when the base material is an opaque base material.

[Brief description of the drawings]

FIG. 1 is a transmission electron micrograph (1 μm bar scale) of an adhesive layer of an adhesive product of Example 10.

FIG. 2 is a transmission electron micrograph (bar scale: 200 nm) of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive product of Example 10.

FIG. 3 is a transmission electron micrograph (bar scale: 1 μm) of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive product of Comparative Example 2.

FIG. 4 is a transmission electron micrograph (bar scale: 200 nm) of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive product of Comparative Example 2.

Claims (5)

[Claims] 1. A pressure-sensitive adhesive product having a (meth) acrylic pressure-sensitive adhesive layer on at least one surface of a support substrate, wherein the pressure-sensitive adhesive layer has a haze value (%) of 30 or less and methanol at room temperature. Value (%) when impregnated for 1 hour
Is 3 or more larger than the original haze value (%). 2. A pressure-sensitive adhesive product having a (meth) acrylic pressure-sensitive adhesive layer on at least one surface of a support substrate, wherein the pressure-sensitive adhesive layer has a haze value (%) of 30 or less, and a pressure-sensitive adhesive layer. Adhesive product characterized in that the sea-island structure can be confirmed when observed with a transmission electron microscope. 3. The pressure-sensitive adhesive layer contains two or more kinds of polymer parts having different glass transition temperatures, and at least one kind of glass transition of other polymer parts than the glass transition temperature of the polymer part (B) having the lowest glass transition temperature. The pressure-sensitive adhesive product according to claim 1, wherein the temperature is higher by 15 ° C. or more, and the difference in refractive index between the polymer part (B) and all other polymer parts is ± 0.05 or less. 4. The pressure-sensitive adhesive product according to claim 3, wherein the polymer part (B) having the lowest glass transition temperature has a weight average molecular weight of 10 × 10 ⁴ or more. 5. The pressure-sensitive adhesive layer contains two or more polymer portions having different glass transition temperatures, and at least one polymer portion is polymerized from a monomer unit in the presence of at least one other polymer portion. Claims 1-4
The adhesive product according to any one of the above.