JPH11140394A - Decorative adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a decorative adhesive sheet which does not become sticky at high-temps. and exhibits a high adhesiveness even at low temps. by forming an acrylic adhesive layer comprising a block copolymer having different polymer blocks (blocks A and B) on one side of a substrate film. SOLUTION: An acrylic adhesive layer comprising a block copolymer having different polymer blocks (blocks A and B) is formed on one side of a substrate film, giving the objective decorative adhesive sheet. The block copolymer is selected from among block copolymers represented by formulas: (A-B)a -A, (B-A)b -B, (A-B)c , and (A-B)d -X and a block copolymer formed by linking block copolymers represented by a formula Ae -Y-Bf with block A or B. In the formulas, a, b, and c are each 1-10; d is 3-30; e and f are each 1 or higher provided e+f is 3-30; X is a compd. capable of linking two or more block copolymers represented by (A-B) ; and Y is a compd. capable of linking block A to block B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a decorative pressure-sensitive adhesive sheet used for outdoor and indoor advertising stickers and display stickers.

[0002]

2. Description of the Related Art A decorative adhesive sheet is provided with a pressure-sensitive adhesive layer on one surface of a material to be decorated, and is used to exhibit a decorative effect by sticking, surface color, pattern, and the like. As labels and stickers, they are widely used in display fields such as advertisements and signboards, and fleet marking fields such as vehicle decoration.

[0003] As such a decorative adhesive sheet, a sheet in which an adhesive layer is formed on one surface of a base film such as a polyvinyl chloride resin film, an acrylic film, or a fluorine-based film has been used. There are various types of base films, such as colored ones containing pigments, transparent ones, and translucent ones.

However, the conventional decorative adhesive sheet uses an acrylic adhesive which is randomly copolymerized in the adhesive layer. For example, in order to suppress stickiness at high temperatures in summer, the adhesive is used. If it is designed rigidly, it will be difficult to achieve the conflicting properties such that the adhesion at low temperatures in winter will be remarkably reduced. When affixed to a material having a concave portion in the field of fleet marking, there is a problem that the sheet floats with time after the application and the initial decorativeness is significantly impaired.

Japanese Patent Application Laid-Open No. 6-234960 discloses a technique in which a fluorine-containing film having excellent flexibility is used as a base material in order to increase the adhesiveness to a curved surface.
However, a fluorine-containing film is more expensive than a general-purpose film, and also has poor printability without surface modification such as sputtering, electron beam treatment, and corona treatment, and the manufacturing process becomes complicated. There was a problem.

[0006]

SUMMARY OF THE INVENTION In view of the above, the present invention has the same manufacturing costs as conventional products, has no stickiness at high temperatures, has high adhesiveness even at low temperatures, and has a high adhesion to curved surfaces. Another object of the present invention is to provide a decorative adhesive sheet that does not impair the decorativeness.

[0007]

The decorative pressure-sensitive adhesive sheet of the present invention is a decorative pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer provided on one surface of a substrate film, wherein the pressure-sensitive adhesive layer is composed of a block A having a different composition. And an acrylic pressure-sensitive adhesive composed of a block copolymer (I) having a block B,
The block copolymer (I) includes a block copolymer represented by the general formula (AB) aA, a block copolymer represented by the general formula (BA) bB, (AB) a block copolymer represented by c, a block copolymer represented by general formula (AB) dX, and a block copolymer represented by general formula Ae-Y-Bf At least two kinds of the same or different polymers selected from the group consisting of coalescing are linked via at least one block A or block B, and the a, b, and c are the same or different. Differently, one
X is an integer of 10 to 10, and X is a plurality of copolymers (A
-B) is a compound capable of binding
Is a compound capable of binding block A and block B, d is an integer of 3 to 30, e and f are the same or different and are integers of 1 or more, and e is
The decorative adhesive sheet satisfies the relationship of + f = 3 to 30.

The base film is not particularly limited as long as it can be formed into a film. Examples of the base film include polyvinyl chloride, soft polyvinyl chloride film, and films made of synthetic resins such as polyurethane, polyolefin and polyethylene terephthalate. No. Above all,
A soft polyvinyl chloride film is preferred in terms of flexibility, weather resistance, and moldability.

Generally, the thickness of the polyvinyl chloride film is preferably from 10 to 200 μm. When the thickness is less than 10 μm, the handleability is poor, and problems such as wrinkles and breakage occur at the time of coating. More preferably,
It is 50 to 100 μm from the viewpoint of ease of use. The polyvinyl chloride film can be obtained, for example, by mixing polyvinyl chloride with a pigment, a dye, a stabilizer, a plasticizer, and the like, and subjecting the mixture to casting or calendering.

[0010] The pressure-sensitive adhesive layer is composed of blocks A having different compositions.
And an acrylic pressure-sensitive adhesive comprising a block copolymer (I) having a block B. Block A above
And the block B is an acrylic block copolymer. The composition of the block A and the block B is different from each other when, for example, the block A is 2
When the block B is a polymer composed of one kind of monomer, the block A and the block B are both copolymers composed of two or more kinds of monomers. And the case where the respective monomer components are different.

The monomer component constituting the block A is an alkyl (meth) acrylate having an alkyl group of 1 to 14 carbon atoms, which can form an acrylic pressure-sensitive adhesive having a glass transition temperature of 0 ° C. or less. The main component is preferably. The alkyl (meth) acrylate having 1 to 14 carbon atoms in the alkyl group is not particularly limited, and examples thereof include (meth) acrylic acid methyl ester, acrylic acid ethyl ester, and (meth) acrylic acid n
-Propyl ester, isopropyl (meth) acrylate, n-butyl (meth) acrylate,
(Meth) acrylic acid sec-butyl ester, (meth)
T-butyl acrylate, cyclohexyl methacrylate, n-octyl (meth) acrylate, isooctyl acrylate, 2-ethylhexyl (meth) acrylate, isononyl acrylate, lauryl (meth) acrylate Esters and the like. These may be used alone or in combination of two or more.

In order to adjust the glass transition temperature and the adhesive strength of the acrylic pressure-sensitive adhesive, another vinyl monomer may be copolymerized. Such copolymerizable vinyl monomers are not particularly limited, and include, for example, styrene monomers such as α-methylstyrene, vinyltoluene and styrene; vinyl ether monomers such as methyl vinyl ether, ethyl vinyl ether and isobutyl vinyl ether ;
Fumaric acid, monoalkyl esters of fumaric acid, dialkyl esters of fumaric acid, maleic acid, monoalkyl esters of maleic acid, dialkyl esters of maleic acid,
Itaconic acid, itaconic acid monoalkyl ester, itaconic acid dialkyl ester, (meth) acrylonitrile, butadiene, isoprene, vinyl chloride, vinylidene chloride, vinyl acetate, vinyl ketone, vinyl pyrrolidone,
Examples thereof include vinyl pyridine, (meth) acrylamide, and vinyl carbazole. These alone are 2
They may be used in combination of two or more.

The monomer component constituting the block B is mainly composed of a vinyl monomer capable of forming a vinyl copolymer having a glass transition temperature of 20 ° C. or higher. The vinyl monomer is not particularly limited, and includes, for example, the above-mentioned copolymerizable vinyl monomers. Methyl methacrylate and styrene are preferably used.

The block copolymer (I) is a block copolymer represented by the general formula (AB) aA, a block copolymer represented by the general formula (BA) bB , A block copolymer represented by the general formula (A-B) c,
-B) at least two kinds of the same or different polymers selected from the group consisting of a block copolymer represented by dX and a block copolymer represented by the general formula Ae-Y-Bf; , Via at least one block A or block B.

The above a, b, and c are the same or different, and
Is an integer of 10 to 10. If it exceeds 10, the viscosity increases,
Since the coatability to the substrate is deteriorated, the content is limited to the above range.
Preferably it is 1-8.

X is a compound capable of binding a plurality of copolymers (AB). The X is not particularly limited. For example, when the copolymer (AB) is obtained by living polymerization such as anionic polymerization, tetrachlorosilane, trichloromethylbenzene, tetrachloromethylbenzene, pentachloromethylbenzene, Examples include a polyfunctional initiator in which three or more halogen-containing groups such as hexachloromethylbenzene are contained in one molecule. The above X is added as a polymerization terminator for the copolymer (AB) to obtain (A
-B) A dX block copolymer can be obtained.

The above Y is a compound capable of binding block A and block B. The above Y is not particularly limited, and for example, a peroxide group in one molecule may be 3
2,2-bis (4,4-di-t)
-Butylperoxycyclohexyl) propane (Nippon Oil & Fat Co., Pertetra A), t-butylperoxy-allyl carbonate (Nippon Oil & Fat Co., Peromer AC), t-
A copolymer obtained by copolymerizing a vinyl group-containing peroxide such as butylperoxy-vinyl carbonate with a monomer constituting the block A or the block B may be used.

The above d is an integer of 3 to 30. E and f are the same or different and are integers of 1 or more;
+ F = 3 to 30 is satisfied.

The block copolymer represented by the general formula (AB) aA, the block copolymer represented by the general formula (BA) b-B, the block copolymer represented by the general formula (AB) A) a block copolymer represented by c, a block copolymer represented by the general formula (AB) dX, and a block copolymer represented by the general formula Ae-Y-
In any of the block copolymers represented by Bf,
The content of the block A is preferably 1 to 40% by weight. If the amount is less than 1% by weight, the cohesive force of the pressure-sensitive adhesive will be insufficient, and if it exceeds 40% by weight, the pressure-sensitive adhesive itself will be too hard, resulting in poor adhesion. More preferably, 1 to 30
% By weight.

The block copolymer represented by the above general formula (AB) aA, the block copolymer represented by the above general formula (BA) bB, the block copolymer represented by the above general formula (AB) A) a block copolymer represented by c, a block copolymer represented by the general formula (AB) dX, and a block copolymer represented by the general formula Ae-Y-
The structure of the block copolymer represented by Bf is not particularly limited, and may be, for example, a linear structure or a star structure. However, it is not preferable to use a macromonomer to obtain a comb structure. The reason for this comes from the process of manufacturing the macromonomer,
The following three points can be cited as problems.

(1) Since the dimer as a by-product is present in the macromonomer itself, the amount of the macromonomer must be reduced in order to suppress the gel generated in the polymerization step. Inevitably, the intended performance cannot be obtained. (2) If the molecular weight of the macromonomer is increased to tens of thousands or more in order to obtain a comb-shaped copolymer having high molecular weight branches, it becomes difficult to introduce a terminal functional group necessary for addition polymerization, and a large amount of Desired physical properties cannot be obtained due to the unreacted oligomers formed. (3) Since macromonomers are generally synthesized by anionic polymerization, the types of monomers that can be used are limited. In particular, since only a small amount of polar groups can be introduced, there is a disadvantage that the degree of freedom in designing is reduced.

In the case of the star-shaped structure, the structure may be such that the block A is inside and the block B is outside, and the block B is inside and the block A is outside. It may be a structure.

The block copolymer (I) preferably has a weight average molecular weight of 10,000 to 2,000,000. If the weight average molecular weight is less than 10,000, the amount of aggregation as an adhesive will be insufficient, and if it exceeds 2,000,000, the viscosity will increase and the coatability will deteriorate. More preferably, it is 100,000 to 1,000,000.

The above-mentioned block copolymer (I) preferably has a glass transition temperature of 0 ° C. or lower. Glass transition temperature is 0
When the temperature exceeds ℃, the sticking property in a low temperature environment in winter is deteriorated. The block copolymer (I) has a measurement frequency of 10
Hz, storage modulus at 100 ° C. in shear mode is 10
Those having a pressure of 10,000 Pa or more are preferable. When the pressure is less than 100,000 Pa, not only stickiness occurs in a high-temperature environment, but also when affixed to an adherend mainly having a curved surface (especially one having a concave portion in a fleet marking field such as a vehicle). Floating or peeling of the sheet occurs over time.

The general formula (AB) aA and the general formula (B)
-A) b-B, general formula (AB) c, general formula (AB)
The method for synthesizing the block copolymer (I) composed of the block copolymer represented by dX and the general formula Ae-Y-Bf is not particularly limited, and examples thereof include a living polymerization method and different reactivity. Examples thereof include a method using an initiator having a starting point, and an ultraviolet polymerization method.

In the living polymerization method, for example, one of the monomers constituting the block A and the monomers constituting the block B is polymerized by using a living polymerizable initiator, and the polymerization is completed. At this point, the monomer constituting the other block is added, and the polymerization is further continued at the terminal of the growing chain, so that the block B or the block A can be polymerized.

The above living polymerization method is not particularly limited. For example, N, N, N ', N'-tetraethyllithium disulfide, benzyl-N, N-diethyldithiocarbamate, p-xylenebis (N, N-diethyl Using an organic lanthanoid compound as an initiator; anionic polymerization using an alkyl lithium or the like as an initiator; group transfer using a silyl ketene acetal or the like as an initiator; starting with aluminum porphyrin Known methods such as a method using as an agent; a metal-free living anion method; and a living radical method can be adopted.

The method of using an initiator having a starting point having a different reactivity is not particularly limited. For example, a method of using an initiator having at least two peroxide groups having different radical generation temperatures; A method using an initiator having at least two peroxide groups can be used. In the method using an initiator having at least two peroxide groups having different radical generation temperatures, for example, the polymerization of any one of the monomer constituting the block A and the monomer constituting the block B is started from a low temperature starting point. By starting the polymerization of one of the block A and the block B, and then starting the polymerization of the monomer constituting the other block from the starting point on the high-temperature side, thereby obtaining the block B or the The polymerization of block A can be performed.

According to the method using an initiator having at least two peroxide groups having different radical generating mechanisms, for example, a monomer is used to form the block A by generating a radical using a reducing agent at one starting point. And after starting the polymerization of any one of the monomers constituting the block B, and after starting the polymerization of any one of the block A and the block B, the temperature is increased to start the other from the other starting point. The polymerization of the block B or the block A can be performed by starting the polymerization of the monomer constituting the block. Specifically, for example, first, the monomer constituting the block A and a radical polymerization initiator having two or more peroxide groups in one molecule are heated and reacted at a set temperature level of 1 to cause the block A to react. Is then polymerized, and then a monomer constituting the block B is added, and the mixture is heated and reacted at a temperature level 2 set to a temperature higher than the temperature level 1 to obtain a block represented by the general formula (AB) c. A copolymer can be synthesized.

The method of using the initiator having a reactive group and a starting point in one molecule is not particularly limited. For example, an initiator having at least one peroxide group and one vinyl group in one molecule And the like. The method using an initiator (D) having at least one peroxide group and one vinyl group in one molecule is as follows:
A photoinitiator different from the initiator (D) or an initiator having low-temperature activity is used to copolymerize either the monomer constituting the block A or the block B with the vinyl group portion of the initiator (D). Then, after polymerizing either the block A or the block B, the monomer constituting the other block is polymerized by the peroxide group of the initiator (D) to polymerize the other block. It can be performed.

In the above-mentioned ultraviolet polymerization, for example, first, either one of the monomer constituting the block B and the monomer constituting the block A is mixed with N, N-diethyldithiocarbamate, and the inside of the reaction vessel is mixed. After purging with nitrogen, an ultraviolet ray (UV) lamp is irradiated with UV to polymerize one of the monomers constituting the block B and the monomers constituting the block A,
Next, a monomer constituting the other block is added, and the other is block-polymerized by UV irradiation, whereby the block copolymer represented by the general formula (AB) a-A, or A block copolymer represented by the general formula (BA) bB can be synthesized.

As another method, for example, the above-mentioned block A having an azo group or the above-described block B having an azo group is polymerized, and another block is formed starting from the azo group. A method of polymerizing the constituting monomers; after previously polymerizing the block A and the block B by ordinary radical polymerization or the like, mixing these and irradiating ultraviolet rays, an electron beam, radiation, or the like, thereby forming the blocks A and A method of performing block connection with the block B may be employed.

In the present invention, a crosslinking agent can be added to the acrylic pressure-sensitive adhesive to improve cohesive strength. The crosslinking agent is not particularly limited, and for example, N,
N'-hexamethylene-1,6-bis (1-aziridinecarbamide), N, N'-diphenylmethane-1,6
Bifunctional or higher functional aziridine compounds such as -bis (1-aziridinecarbamide) and trimethylol-tri-β-aziridinylpropionate; isocyanate compounds such as hexamethylene diisocyanate and tolylene diisocyanate adduct of trimethylolpropane N, N,
Epoxy crosslinking agents such as N ', N'-tetraglycidyl-m-xylenediamine; alkyl etherified melamine resins, polyvalent metal salts, metal chelates and the like.

If necessary, the acrylic pressure-sensitive adhesive may contain conventionally known additives such as tackifier resins, plasticizers, softeners, fillers, antioxidants, ultraviolet absorbers, pigments, dyes, and the like. It may be added.

The thickness of the pressure-sensitive adhesive layer is preferably 5 to 100 μm. If the thickness is less than 5 μm, there is a problem that a desired adhesive strength cannot be obtained or a glue residue occurs when a sheet is reattached. If the thickness is more than 100 μm, glue overflows and is uneconomical. More preferably, 15-50μ
m.

The method for producing the decorative pressure-sensitive adhesive sheet of the present invention includes, for example, applying a predetermined compound such as an acrylic pressure-sensitive adhesive and an organic solvent onto a base film, followed by drying to evaporate the organic solvent. An adhesive layer is provided on the material film. The coating machine that can be used for applying the pressure-sensitive adhesive is not particularly limited as long as it is used for normal pressure-sensitive adhesive solution coating. For example, a knife coater that can accurately adjust the thickness and can be coated with high productivity. , A comma roll coater, a roll coater and the like. In addition, as an application method, in addition to the method of directly applying and drying the adhesive on the base film as described above, the adhesive layer is formed by once applying an adhesive solution to release paper and then drying. Then, a transfer method or the like by sticking to the above-mentioned base film can also be used.

The decorative pressure-sensitive adhesive sheet thus produced is usually stored as a laminate in which a release sheet is bonded to the surface of the pressure-sensitive adhesive layer, and the release sheet is peeled off from the surface of the pressure-sensitive adhesive layer when used. . The release sheet is not particularly limited as long as it has a supporting force and has a release layer capable of releasing the acrylic pressure-sensitive adhesive layer. Examples thereof include nonwoven fabrics, synthetic fibers, and nets. , Paper, plastic film, and various sheet-like bodies such as a laminate of a polyolefin film and paper coated with a material for forming a release layer. Specific examples include paper coated with a silicone resin, polyethylene terephthalate film, and the like.

(Function) In the decorative pressure-sensitive adhesive sheet of the present invention, by using an acrylic pressure-sensitive adhesive composition having a block structure as a pressure-sensitive adhesive layer, a conventional pressure-sensitive adhesive layer mainly composed of a random copolymer can be formed. This can solve the trade-off problem of sticky decorative sheets that have been a problem for many years, such as stickiness in summer and poor adhesion in winter. That is, since a phase-separated structure is formed in the pressure-sensitive adhesive composition system composed of the block copolymer, the properties of each component can be strongly maintained. If the glass transition point temperature and the elastic modulus can be set appropriately, it is possible to give the pressure-sensitive adhesive contradictory properties such as flexibility in a low temperature region and suppression of fluidity in a high temperature region. Therefore, the above-mentioned problems such as stickiness in summer and poor bonding in winter can be solved together.

Further, in the acrylic pressure-sensitive adhesive composition having a block structure, it is possible to maintain a high-temperature elastic modulus associated with the formation of a physical crosslinked structure in a block portion having a high glass transition temperature, thereby enhancing the toughness of the pressure-sensitive adhesive. . If the toughness of the pressure-sensitive adhesive can be improved, the resistance to stress increases, and even when the pressure-sensitive adhesive is used for an adherend mainly having a curved surface, it is possible to effectively suppress the occurrence of floating and peeling.

[0040]

EXAMPLES Hereinafter, the present invention will be clarified by giving Examples and Comparative Examples of the present invention, but the present invention is not limited to only these Examples.

Example 1 Production of pressure-sensitive adhesive (first step) In a 2 L separable flask equipped with a stirrer, a cooler, a thermometer and a nitrogen gas inlet, 300.0 g of butyl acrylate (BA) in one molecule Compound having a copolymerizable double bond and a peroxide bond: 1.35 g of t-butylperoxyallyl carbonate (Peromer AC, manufactured by NOF Corporation), 0.09 g of dodecyl mercaptan (DDM) as a chain transfer agent, and a photoinitiator 0.15 g of benzyl methyl ketal (Irgacure 651, manufactured by Ciba Geigy) and 245.45 g of ethyl acetate as a polymerization solvent. Dissolved oxygen was removed by bubbling the monomer mixed solution with nitrogen gas for 20 minutes. Subsequently, while bubbling the monomer mixed solution with nitrogen gas and stirring at a rotation speed of 100 rpm, light having a wavelength of 365 nm was emitted for 2 m using a chemical lamp.
The polymerization was started by irradiation with W intensity. The polymerization reaction was carried out for 4 hours with the time when the temperature increase was confirmed as the polymerization start point.

(Second Step) In a 2 L separable flask equipped with a stirrer, a condenser, a thermometer and a nitrogen gas inlet, 250 g of the polyBA / ethyl acetate solution obtained in the first step was weighed, and then methacrylic acid was added. Acid methyl ester (MMA)
10.75 g, acrylic acid (AAc) 4.60 g and methacrylic acid 2-hydroxyethyl ester (2HEM
A) 0.8 g was added. Ethyl acetate as a polymerization solvent was mixed with 1% so that the total solid content was 55% by weight.
3.21 g were added. Polymer / monomer mixed solution
After removing dissolved oxygen by bubbling with nitrogen gas for 20 minutes, the inside of the separable flask is replaced with nitrogen gas, and the polymer / monomer mixed solution is heated using a water bath while stirring at 60 rpm. Was. The boiling point polymerization reaction was carried out for 4 hours with the time when the reflux liquid was confirmed in the cooling tube as the starting point of the polymerization, to obtain the target acrylic copolymer. The weight average molecular weight of the obtained polymer was 503,000, and the polydispersity was 3.88.

Production of decorative adhesive sheet (base film) In order to prepare a base film, a vinyl chloride-based organosol composition having the following composition was prepared using a dissolver stirrer, and this was mixed with alkyd resin on high quality paper. 170 μm thick release sheet (DNTP-N
ML, manufactured by Dai Nippon Printing Co., Ltd.)
After preliminary drying at 20 ° C. for 1 minute, the substrate was heated at 200 ° C. for 1 minute and cured to obtain a base film having a thickness of 50 μm.

The vinyl chloride-based organosol composition comprises 100 parts by weight of a vinyl chloride resin (Zeon 121, manufactured by Zeon Corporation) and a metal stabilizer (MARK-A, manufactured by Adeka Argus Co., Ltd.).
P551) 7 parts by weight, 0.5 part by weight of a benzotriazole-based ultraviolet absorber (Ciba Geigy, Chiapin 326), polyester-based plasticizer (Adeka Argus, P-
300) 30 parts by weight, and 60 parts by weight of a hydrocarbon solvent (Solvesso # 150, manufactured by Shell Chemical Co., Ltd.).

(Pressure-sensitive adhesive layer) Ethyl acetate solution (solid content: 45% by weight) of methylolpropane tolylene diisocyanate trimer adduct as a crosslinking agent was added to the obtained pressure-sensitive adhesive solution.
(Coronate L45, manufactured by Nippon Polyurethane Co., Ltd.) was added in an amount of 2.5 parts by weight based on 100 parts by weight of the acrylic copolymer.
Coating was performed so as to have a thickness of 0 μm, followed by drying at 110 ° C. for 5 minutes to obtain a pressure-sensitive adhesive layer. The decorative adhesive sheet was obtained by laminating the adhesive layer on the base film. The following evaluation was performed about the obtained decorative adhesive sheet. The results are shown in Table 1.

Evaluation of Adhesive Performance Evaluation of Adhesive Strength An SP plate was prepared as an adherend, a sample cut in a width of 25 mm was adhered, and a 2 kg weight roller was pressed once and then pressed, and after 20 minutes, 300 mm / min. At the speed of 1
The 80 ° peel force was measured.

Evaluation of workability of curved surface (concave surface) A length 20 was added to the ends A and B of the aluminum plate processed as shown in FIG.
A decorative adhesive sheet of about 0 mm was passed, and the decorative adhesive sheet was attached to an aluminum plate so as to be pushed in while being extended.
The state of floating of the decorative adhesive sheet one week after the construction was evaluated according to the following evaluation criteria. ：: No film lifting △: Floating occurs at a very small portion ×: Floating occurs at 50% or more of the adhered area

Evaluation of Retention Force A sample was attached to an SP plate with a width of 25 mm, a 100 g weight was hung, and a shift value after 2 hours under a temperature condition of 60 ° C. was measured.

Evaluation of Workability Under a low temperature (5 ° C.) and high temperature (30 ° C.) environment, a sample having a width of 50 mm was stuck on an SP plate, and the ease of sticking during the work was evaluated according to the following valuation criteria. (Low temperature (5 ° C.)) ：: Good adhesion to the adherend and good workability. Δ: Slightly difficult to adhere and workability is somewhat difficult. ×: Poor adhesion to the adherend and easy peeling. (High temperature (30 ° C.)) ：: The glue surface is not sticky and the workability is good. Δ: The glue surface is slightly sticky and difficult to perform. X: The glue surface is very sticky, positioning is difficult, and workability is poor.

Dynamic Viscoelasticity Evaluation The dynamic viscoelasticity spectrum of the obtained acrylic copolymer was measured using DVA-320 manufactured by IT Measurement Control Co., Ltd. The main measurement conditions were as follows. Measurement temperature range: -40 to 120 ° C Frequency: 10Hz Heating rate: 3 ° C / min Data acquisition interval: 3 ° C

Comparative Example 1 2 equipped with a stirrer, a cooler, a thermometer and a nitrogen gas inlet
In an L-separable flask, 268.5 g of BA, AAc9
g, 21 g of MMA, 1.5 g of 2HEMA, and 245.45 g of ethyl acetate as a polymerization solvent. After the dissolved oxygen was removed by bubbling the monomer mixed solution with nitrogen gas for 20 minutes, the inside of the separable flask system was replaced with nitrogen gas, and the monomer mixed solution was stirred using a water bath while stirring at 100 rpm. The solution was warmed.

When the reflux liquid is confirmed in the cooling tube, 1,1-di (t-hexylperoxy) as a polymerization initiator is used.
0.03 g of -3,3,5-trimethylcyclohexane (Perhexa TMH, manufactured by NOF CORPORATION) was dissolved in about 1 g of ethyl acetate and charged to initiate boiling point polymerization. One hour later, 0.09 g of perhexa TMH was added again for about 1 hour.
g of ethyl acetate. Further, 2 hours, 3 hours, and 4 hours after the start of polymerization, di (3,5,5-trimethylhexanoyl) peroxide (perloyl 355,
0.12 g, 0.30 g and 0.90 g
Was dissolved in about 1 g of ethyl acetate and charged. The desired random polymer was obtained by conducting the boiling point polymerization for 7 hours. The weight average molecular weight of the obtained polymer was 534,000, and the polydispersity was 2.88. Using the obtained polymer, a decorative adhesive sheet was produced in the same manner as in Example 1, and the adhesive performance was evaluated. The results are shown in Table 1.

Comparative Example 2 A sample equipped with a stirrer, a cooler, a thermometer and a nitrogen gas inlet was prepared.
In an L-separable flask, 268.5 g of BA, AAc9
g, MMA macromonomer (AA-6, manufactured by Toa Gosei Chemical Industry Co., Ltd., Mw = 6000) 21 g, 2HEMA 1.5 g
And 245.45 g of ethyl acetate as a polymerization solvent. After the dissolved oxygen was removed by bubbling the monomer mixed solution with nitrogen gas for 20 minutes, the inside of the separable flask system was replaced with nitrogen gas, and the monomer mixed solution was stirred using a water bath while stirring at 100 rpm. The solution was warmed. When the reflux liquid is confirmed in the cooling tube, 0.06 g of 1,1-di (t-hexylperoxy) -3,3,5-trimethylcyclohexane (PerhexaTMH, manufactured by NOF Corporation) as a polymerization initiator Was dissolved in about 1 g of ethyl acetate and charged to initiate boiling point polymerization. After one hour, again with Perhexa TMH
0.09 g was dissolved in about 1 g of ethyl acetate and charged. However, three hours after the start of the reaction, the polymerization reaction was terminated because gelation occurred in the separable flask system, and a decorative adhesive sheet could not be produced.

Comparative Example 3 An acrylic polymer was obtained in the same manner as in Example 1 except that the amount of DDM added in the first step was 1.00 g, and that 0.1 g of DDM was also added in the second step. The weight average molecular weight of the obtained polymer was 0.830, and the polydispersity was 2.20. Using the obtained polymer, a decorative adhesive sheet was produced in the same manner as in Example 1, and the adhesive performance was evaluated. The results are shown in Table 1.

[0055]

[Table 1]

[0056]

Since the decorative adhesive sheet of the present invention has the above-mentioned structure, it solves problems such as stickiness in summer and poor sticking in winter, and always exhibits excellent adhesive performance without being affected by the working environment. However, even when attached to an adherend mainly composed of a curved surface (particularly, a concave portion in the field of fleet marking such as a vehicle), the sheet does not float or peel off.

[Brief description of the drawings]

FIG. 1 is a schematic diagram for explaining evaluation of curved (concave) workability.

Claims (5)

[Claims] 1. A decorative pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer provided on one surface of a base film, wherein the pressure-sensitive adhesive layer is made of a block copolymer (I) having blocks A and B having different compositions. Wherein the block copolymer (I) is a block copolymer represented by the general formula (AB) a-A, and the block copolymer (I) is a general formula (BA) b-B A block copolymer represented by the general formula (AB) dX, a block copolymer represented by the general formula (AB) dX, and a block copolymer represented by the general formula (Ae) At least two kinds of the same or different polymers selected from the group consisting of the block copolymers represented by -Y-Bf are bonded via at least one block A or block B; , A, b, and c are the same or different, and
X is an integer of 10 to 10, and X is a plurality of copolymers (A
-B) is a compound capable of binding
Is a compound capable of binding the block A and the block B, d is an integer of 3 to 30, e and f are the same or different and are integers of 1 or more, e
A decorative pressure-sensitive adhesive sheet which satisfies a relationship of + f = 3 to 30. 2. The monomer component constituting the block A is:
The main component is an alkyl (meth) acrylate having an alkyl group having 1 to 14 carbon atoms, which can form an acrylic pressure-sensitive adhesive having a glass transition temperature of 0 ° C. or lower. Constituent monomer components are
The decorative pressure-sensitive adhesive sheet according to claim 1, which is mainly composed of a vinyl monomer and can form a vinyl-based copolymer having a glass transition temperature of 20 ° C or higher. 3. The decorative pressure-sensitive adhesive sheet according to claim 1, wherein the weight average molecular weight of the block copolymer (I) is 10,000 to 2,000,000. 4. The block copolymer (I) has a glass transition temperature of 0 ° C. or lower and a measurement frequency of 100 H
z, storage modulus at 100 ° C. in shear mode is 10
The decorative pressure-sensitive adhesive sheet according to claim 1, wherein the pressure-sensitive adhesive sheet has a pressure of 10,000 Pa or more. 5. The decorative pressure-sensitive adhesive sheet according to claim 1, wherein the base film is a soft polyvinyl chloride film.