JPH09164637A - Thermal printing self-adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermal printing self-adhesive sheet well keeping initial sharpness even when a thermally developed color patterns are continuously formed through thermal printing to show excellent continuous printability, capable of being easily unwound to be used even when directly bonded to a thermal printing sheet through its self-adhesive layer without using a separator to be formed into a wound object, capable of dispensing with a separate separator covering the self-adhesive layer and keeping thermally developed color patterns when the wound object formed after preliminarily imparting thermally developed color patterns is unwound. SOLUTION: This sheet is constituted by providing a thermal color forming layer 2 on the single surface of a heat insulating sheet 3 and providing a release coating layer 1 composed of a curing film of a silicone polymer containing two or more acryloyl groups or methacryloyl groups in its molecule on the upper surface thereof and providing a self-adhesive layer 4 to the other surface of the heat insulating sheet. By this constitution, the release coating layer can be provided while keeping the thermal color properties of a thermal printing sheet.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to the formation of a label, which can form a clear thermosensitive coloring pattern through thermal printing with good continuity and which can be put to practical use as a roll or the like without a separator for protecting an adhesive layer. The present invention relates to a heat-printable pressure-sensitive adhesive sheet suitable for.

[0002]

BACKGROUND OF THE INVENTION Conventionally, there has been known a thermal printing adhesive sheet in which an adhesive layer is provided on one surface of a thermal paper and the adhesive surface is protected by a separator. This heat-printing pressure-sensitive adhesive sheet is provided with a pattern through a heat transfer printer or the like to form a label issued on site, which can be peeled off the separator to be adhered to an adherend. As the separator, a paper or polymer film coated with a silicone-based cured film has been proposed (Japanese Patent Laid-Open No. 64-8052).
No. 5, JP-A-3-68670, JP-A 4-8
No. 5027 publication)

However, there is a problem that it is necessary to temporarily protect the adhesive layer with a separator for practical use. That is, when a wound body is formed by a method of adhering to the back surface of the thermal paper without a separator, the thermal paper is ruptured during the rewinding so that the rewinding is substantially impossible, and therefore the adhesive layer is separately provided. It was necessary to cover it with the separator and put it into practical use. However, the separator is to be peeled and removed from the adhesive layer when it is practically used as a label, and the peeling and removing work is required when it is adhered to an adherend.
Since unnecessary products such as dust may be generated, it is required to eliminate them. Further, when a thermosensitive coloring pattern is continuously formed through thermal printing using a thermal transfer printer or the like, the sharpness of the thermosensitive coloring pattern formed from the time when the thermal printing has progressed to a certain degree is deteriorated, and the problem of poor continuous printability is a problem. was there.

[0004]

DISCLOSURE OF THE INVENTION The present invention has excellent continuous printability by maintaining good initial sharpness even when a thermosensitive coloring pattern is continuously formed through thermal printing, and it has an adhesive layer. It can be easily rewound when used as a wound body by directly adhering to the back surface of the thermal printing sheet without a separator, and therefore a separate separator that covers the adhesive layer can be eliminated and a thermosensitive coloring pattern. An object of the present invention is to obtain a heat-printed pressure-sensitive adhesive sheet which is preliminarily applied to form a wound body and maintains a heat-sensitive color development pattern in a good state when it is rewound.

[0005]

According to the present invention, a release coat comprising a heat-sensitive coloring layer on one side of a heat insulating sheet and a cured film of a silicone-based polymer containing at least two acryloyl groups or methacryloyl groups in the molecule on its upper surface. There is provided a thermal printing pressure-sensitive adhesive sheet having a layer and having an adhesive layer on the other surface of the heat insulating sheet.

[0006]

EFFECTS OF THE INVENTION The above silicone-based polymer can form a cured film by low-temperature treatment by irradiation with ionizing radiation, and can protect the thermosensitive color developability of a thermal printing sheet. As a result, a wound body with good adhesion can be formed by directly adhering to the release coating layer made of the cured film on the back side of the thermal printing sheet via the adhesive layer on the back side, and the wound body can be rewound to obtain commercially available thermal transfer. The heat-sensitive color-developing pattern can be thermally printed through a printer or the like, and a label or the like having a pattern with excellent sharpness can be issued on site. Therefore, a separate separator that covers the adhesive layer can be eliminated.

Furthermore, a method of continuously applying a thermosensitive coloring pattern in advance through a thermal transfer printer or the like makes it possible to continuously form a large number of patterns in which the initial sharpness is maintained well, and after that, the pattern is rewound as a wound body. Can be easily rewound in a state in which the heat-sensitive coloring pattern is maintained well, and the peeling force has a small dependence on the rewinding speed and exhibits a stable rewinding property.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The heat-printing pressure-sensitive adhesive sheet of the present invention has a heat-sensitive coloring layer on one side of a heat insulating sheet and has an acryloyl group or a methacryloyl group in the molecule on the upper surface thereof.
It has a release coat layer composed of a cured film of a silicone-based polymer containing one or more of them, and an adhesive layer on the other surface of the heat insulating sheet. Examples thereof are shown in FIGS. 1 and 2.
1 is a release coat layer, 2 is a thermosensitive coloring layer, 3 is a heat insulating sheet,
4 is an adhesive layer. Further, 5 is an ultraviolet shielding layer provided as necessary.

The purpose of the heat insulating sheet is to make it possible to continuously form a large amount of a heat-sensitive coloring pattern by thermal printing in a clear state. That is, in a conventional thermal printing sheet such as thermal paper, when a thermal coloring pattern is continuously formed by thermal printing, there is a temperature rise due to heat accumulation in a thermal printing device such as a thermal transfer printer. However, there is a problem in that the color difference between the color-developed portion and the color-developed portion due to thermal printing is reduced and the sharpness of the heat-sensitive color-developed pattern is reduced, and the use of a heat insulating sheet aims to prevent such a problem from occurring.

The heat insulating sheet may be made of a suitable material such as paper or polymer and is not particularly limited. Preferably, the thermal conductivity is 3.5 × 1/10 ⁴ cal /
cmS ° C or less, especially 3.3 × 1/10 ⁴ cal / cmS ° C or less,
Particularly, it is 3.0 × 1/10 ⁴ cal / cm S ° C. or less.

A thin heat insulating sheet is advantageous over obtaining a thin printed sheet, and a foamed sheet is preferably used because of its advantage. The foamed sheet may be formed by an appropriate method, for example, a thermoplastic polymer containing a foaming agent and subjected to a foaming treatment, or a molded sheet of a thermoplastic polymer obtained by supplying air or the like to an extruder. A product obtained by injecting air etc. and foaming at the same time, a product obtained by mixing bubbles into an emulsion of a thermoplastic polymer by mechanical forced agitation and expanding it into a sheet and solidifying it, or a melt of the thermoplastic polymer. Examples thereof include those sprayed with gas by a suitable method such as a slot spray method, a curtain spray method, and a melt blow method, deposited in a sheet form, and cooled and solidified.

The thermoplastic polymer forming the foamed sheet is not particularly limited, and any suitable one can be used. By the way, for example, polyethylene or polypropylene,
Olefin polymers such as ethylene / propylene polymers and chlorinated polyethylene, polyamides and polyesters, polyvinyl acetate and ethylene / vinyl acetate copolymers,
Acrylic polymers such as urethane polymers and poly (meth) acrylic acid alkyl esters, polyvinyl chloride and styrene polymers, silicone polymers and natural rubber, polyisobutylene and polyisoprene, chloroprene rubber, isoprene / isobutylene rubber, nitrile butyl rubber and Styrene / butadiene rubber, styrene / butadiene / styrene rubber, styrene / isoprene / styrene rubber, styrene / ethylene / butadiene rubber or styrene /
Examples include plastic-based and rubber-based polymers such as ethylene / butylene / styrene rubber, styrene / isoprene / propylene / styrene rubber and ethylene / propylene terpolymer, and blends thereof.

In the present invention, since the release coating layer can be formed at a low temperature, a heat insulating sheet made of, for example, polyethylene having a crystal melting temperature of 120 ° C. or less can be used. The heat insulating sheet may be a composite sheet using a reinforcing base material such as fiber, cloth, non-woven fabric or metal foil, or two or more kinds such as a foam sheet, paper or polymer film depending on the purpose of use of the thermal printing adhesive sheet. It may be formed as a used laminate or the like.

The thickness of the heat insulating sheet may be appropriately determined depending on the purpose of use of the thermal printing adhesive sheet. Generally,
The thickness is 1 mm or less, preferably 500 μm or less, particularly 20 to 200 μm. In terms of winding property and curved surface adhesion,
A heat insulating sheet having excellent flexibility can be preferably used. Further, the heat insulating sheet can be colored in an appropriate color such as white by incorporating an appropriate colorant such as a pigment such as silica, titania, alumina, zinc white, zirconia, calcium oxide, mica.

The heat-printable sheet can be formed by providing a heat-sensitive coloring layer on one side of the heat insulating sheet. The thermosensitive coloring layer can be appropriately formed, for example, as a layer obtained by imparting thermosensitive coloring property with a leuco dye and a color developer, or can be formed as an adhesive attachment layer of commercially available thermosensitive paper. The thickness of the thermosensitive coloring layer is 500μ
It is generally m or less, especially 200 μm or less, and particularly 5 to 100 μm, but is not limited to this.

The release coating layer provided on the upper surface of the thermosensitive coloring layer is formed of a silicone polymer containing two or more acryloyl groups or methacryloyl groups in the molecule. As a result, unlike a thermosetting silicone polymer such as a condensation reaction type or an addition reaction type, a cured film can be formed by irradiation treatment with ionizing radiation, and thus a cured film can be formed at a low temperature treatment, resulting in a heat-sensitive coloring layer. Colorability can be maintained. In the case of a thermosetting type, color is developed during the heat treatment to make the pattern formation impossible.

The above-mentioned silicone-based polymer contains, for example, an organosiloxane having a suitable organic group such as an alkyl group having 1 to 20 carbon atoms such as a methyl group, a cycloalkyl group, an aryl group or an aralkyl group, and a polymer thereof. However, as the functional group imparting curability by ionizing radiation, those having only an acryloyl group and / or a methacryloyl group are preferable.

The steadiness of the peeling force independent of the peeling speed,
Silicone-based polymers that can be particularly preferably used in terms of adhesion to the adhesive surface are silicone-based polymers having a number average molecular weight of 2,000 to 30,000 containing 2 to 20 functional groups consisting of acryloyl groups or methacryloyl groups in the molecule. Oligomer 95
˜50 parts by weight, especially 80 to 60 parts by weight, and 5 to 50 parts by weight of a silicone-based oligomer containing 3 to 20 functional groups in the molecule and having a number average molecular weight of 500 to 5,000, especially 20 to
It is a mixture with 40 parts by weight.

The release coating layer is formed by coating the silicone polymer on the thermosensitive color developing layer with an appropriate device such as a squeeze coater and irradiating the coating layer with ionizing radiation to cure the coating. And the like. In that case, the coating amount of the silicone-based polymer, 0.05-5 g / m ^2, preferably especially 0.1 to 3 g / m ^2. If the coating amount is less than 0.05 g / m ² , the peeling force may be large due to insufficient film thickness, and the peeling force may not be stable. A coating amount of more than 5 g / m ² is not very useful, because it takes a lot of time for irradiation treatment.

When coating the silicone-based polymer, an appropriate photodegradable active material can be added if necessary. Examples thereof include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin compounds such as anizoin methyl ether, benzyl compounds such as benzyl and benzyl dimethyl ketal, 4- (2-hydroxyethoxy) phenyl. (2-hydroxy-2-propyl)
Ketone, α-hydroxy-α, α′-dimethylacetophenone, methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 1-hydroxycyclohexylphenylketone, 2-methyl-1- [ Acetophenone compounds such as 4- (methylthio) -phenyl] -2-morpholinopropane-1 can be mentioned.

Further, α-ketol compounds such as 2-methyl-2-hydroxypropiophenone, aromatic sulfonyl chloride compounds such as 2-naphthalenesulfonyl chloride, 1-phenone-1,1-propanedione-2.
Photoactive oxime compounds such as-(ο-ethoxycarbonyl) oxime, benzophenone and benzoylbenzoic acid, benzophenone compounds such as 3,3'-dimethyl-4-methoxybenzophenone, thioxanthone and 2-chlorothioxanthone, 2- Methylthioxanthone or 2,
Thioxanthone compounds such as 4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone and 2,4-diisopropylthioxanthone, camphorquinone and halogen Ketones, acyl phosphinoxides and acyl phosphonates are also examples of photodegradable active materials.

The silicone-based polymer can be coated by a solventless coating method which is advantageous in the work environment, but it does not exclude the diluted coating by using an organic solvent which does not impair the thermosensitive coloring property of the thermosensitive coloring layer. Absent. As the ionizing radiation for irradiation treatment, any appropriate one can be used, but among them, the wavelength is 400
Ionizing radiation having a wavelength of nm or less, for example, ultraviolet rays from a medium or high pressure mercury lamp, an electron beam, a gamma ray or the like can be preferably used.

In forming the release coat layer in the present invention, an ultraviolet light shielding layer 5 may be optionally interposed as shown in FIG. The ultraviolet shielding layer is provided between the release coat layer 1 and the thermosensitive coloring layer 2 for the purpose of improving durability. Therefore, when the ultraviolet shielding layer is provided, the release coating layer is formed after the ultraviolet shielding layer is provided on the thermosensitive coloring layer.

The ultraviolet shielding layer is, for example, a coating layer of an ultraviolet absorber such as a salicylate compound, a benzophenol compound, a benzotriazole compound, a cyanoacrylate compound, a nickel complex salt compound, or a transparent resin containing an ultraviolet absorber. It can be formed as an appropriate layer having an ultraviolet absorbing ability, such as a layer.

An appropriate adhesive substance can be used to form the adhesive layer provided on the back surface of the heat insulating sheet. Generally, for example, rubber-based adhesives, acrylic-based adhesives, silicone-based adhesives, vinyl alkyl ether-based adhesives, polyvinyl alcohol-based adhesives, polyvinylpyrrolidone-based adhesives, polyacrylamide-based adhesives and cellulose-based adhesives, etc. An organic type is used.

The type of the pressure-sensitive adhesive is not particularly limited, and the release coating layer according to the present invention shows good adhesion to a pressure-sensitive adhesive layer made of a water-based emulsion type or a solution type pressure-sensitive adhesive made of an organic solvent, so that foaming or Such a liquid type pressure-sensitive adhesive that can easily form a pressure-sensitive adhesive layer having an excellent adhesive force on a smooth surface without floating can be preferably used.

The pressure-sensitive adhesive layer is formed by applying a pressure-sensitive adhesive layer provided on the separator on a predetermined surface of the heat insulating sheet by an appropriate method such as a rolling method such as a calendar roll method or a sheet forming method such as a doctor blade method or a gravure roll coater method. It can be performed by an appropriate method such as a method of transferring to. The thickness of the adhesive layer can be appropriately determined according to the purpose of use, etc.
It is set to 500 μm.

The preferred method for forming the adhesive layer is a method in which the adhesive layer is directly applied to a predetermined surface of the heat insulating sheet. According to this, a separator can be made unnecessary in all steps of manufacturing the thermal printing adhesive sheet. Such a direct coating method can be achieved by directly attaching an adhesive layer to the exposed back surface of the heat insulating sheet, for example, in the case of coating an adhesive, if the solvent or the like does not interfere with the thermosensitive coloring property of the thermosensitive coloring layer. it can.

On the other hand, when it is difficult to directly attach the adhesive layer to the back surface of the heat insulating sheet, for example, an adhesive is applied on the release coat layer to form the adhesive layer, and the adhesive layer is formed. This can be achieved by a method of adhering the adhesive layer to the back surface of the heat insulating sheet by an appropriate method such as a winding method of adhering to the back surface of the heat insulating sheet, or a method of laminating with a separate heat insulating sheet.

The thermal printing pressure-sensitive adhesive sheet of the present invention comprises a printing pattern or a pattern pattern, which is formed by partially heating the thermosensitive coloring layer by a suitable thermal printing method using a thermal transfer printer or the like to develop the thermosensitive coloring.
Any pattern such as a bar code pattern can be formed. Therefore, it can be used to form an appropriate pattern sheet such as an identification label. In that case, in addition to being used for forming a label or the like in a form with a separator as in the conventional case, while forming a thermosensitive coloring pattern by a continuous printing method or the like in the thermal printing adhesive sheet of the present invention, it is applied to It can also be put into practical use by forming it into a wound body via an adhesive layer.

Before forming the heat-sensitive color-developing pattern, it is formed into a wound body through an adhesive layer on its own back surface, and the heat-sensitive color-developing pattern is added to the wound body by an appropriate method such as a heating pen or a heating stamp. Labels and the like can also be formed. The formed label or the like can be adhered to the adherend through the adhesive layer on the back surface by cutting the wound body to a predetermined size while appropriately rewinding the wound body.

[0032]

【Example】

Example 1 A heat-sensitive paper (Everthermax KPT58-3H, manufactured by Shin-Oji Paper Co., Ltd.) was applied to a heat insulating sheet having a thickness of 60 μm and made of expanded polyethylene having a thermal conductivity of 2.9 × 1/10 ⁴ cal / cm S ° C.
Having a number average molecular weight of 5 containing 2 to 20 acryloyl groups and / or methacryloyl groups in the molecule.
000 silicone-based oligomers (Shin-Etsu Chemical Co., Ltd.,
The same applies hereinafter) 70 parts (parts by weight, the same below) and a mixture of 30 parts by weight of a silicone-based oligomer having a number average molecular weight of 1400 and containing 3 to 20 acryloyl groups and / or methacryloyl groups in a squeeze coater. 2.0 g
Coating at a ratio of / m ² and applying it to a low-voltage electron beam accelerator (E
A CB-150 manufactured by SI Co., Ltd.) was used to irradiate an absorbed dose of 30 kGry at an accelerating voltage of 165 kv to form a cured film, and then a thickness 2 provided on the separator on the other surface of the heat insulating sheet.
A rubber-based pressure-sensitive adhesive layer having a thickness of 0 μm was transferred to obtain a heat-printing pressure-sensitive adhesive sheet.

Example 2 Thermal paper (Everthermax KPT-300-9J, manufactured by Shin Oji Paper Co., Ltd.) was adhered to a heat insulating sheet made of expanded polyethylene having a thermal conductivity of 2.54 × 1/10 ⁴ cal / cm S ° C. And a number average molecular weight of 1200 containing 2 to 20 acryloyl groups and / or methacryloyl groups in the molecule.
80 parts of 0-based silicone oligomer and 3 to 20 acryloyl groups and / or methacryloyl groups in the molecule and having a number average molecular weight of 1200 Silicone oligomer 2
1.5 g / m ² obtained by adding 1 part of a photoinitiator (manufactured by Ciba-Geigy, Irgacure 184) to a mixture with 0 part by weight.
A thermal printing pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the coating was carried out at the ratio of.

Comparative Example Instead of the heat insulating sheet, the thermal conductivity was 3.63 × 1/10 ⁴ c.
A thermal printing pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that a polyethylene sheet of al / cmS ° C was used.

Evaluation Test The following characteristics of the thermal printing pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples were examined. Continuous printability Using a commercially available thermal transfer printer, pattern units for 3000 labels are continuously printed on the thermosensitive coloring side of the thermoprinting adhesive sheet, and the thermosensitive coloring pattern of the formed 2500 to 3000 labels is visually observed. The case where the pattern was clear as in the initial state was evaluated as ◯, and the case where the pattern other than the part to which the pattern was applied was colored and the pattern was unclear was evaluated as x.

Decolorizing property (rewinding property) A commercially available thermal transfer printer is used to continuously print on the heat-sensitive color developing side of a heat-printing pressure-sensitive adhesive sheet, and at the same time, it is adhered to the back side of the roll via a pressure-sensitive adhesive layer to form a roll at room temperature. After leaving it for 24 hours, it was rewound and visually examined for decoloration by comparison with the initial printed state. When no change from the initial printed state was observed, it was evaluated as ◯, and in other cases, it was evaluated as x.

The above results are shown in the following table.

[Brief description of the drawings]

FIG. 1 is a sectional view of an embodiment.

FIG. 2 is a sectional view of another embodiment.

[Explanation of Codes] 1: Release coat layer 2: Thermosensitive coloring layer 3: Thermal insulation sheet 4: Adhesive layer 5: Ultraviolet shielding layer

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location B32B 7/10 B32B 7/10 27/18 27/18 A C09J 7/02 JJA C09J 7/02 JJA JJH JJH JKV JKV G09F 3/02 G09F 3/02 F (72) Inventor Naofumi Mihara 1-2 1-2 Shimohozumi, Ibaraki-shi, Osaka Prefecture Nitto Denko Corporation (72) Inventor Isao Okazaki 1-chome, Shimohozumi, Ibaraki-shi, Osaka Prefecture 1-2, Nitto Denko Corporation (72) Inventor, Kihachi Suzuki 1-2-1, Shimohozumi, Ibaraki City, Osaka Prefecture Nitto Denko Corporation

Claims (4)

[Claims] 1. A heat-sensitive coloring layer is provided on one side of a heat insulating sheet, and a release coating layer made of a cured film of a silicone-based polymer containing two or more acryloyl groups or methacryloyl groups in the molecule is provided on the upper surface thereof. A thermal printing adhesive sheet having an adhesive layer on the other surface of the heat insulating sheet. 2. The thermal printing pressure-sensitive adhesive sheet according to claim 1, which has an ultraviolet shielding layer between the thermosensitive coloring layer and the release coating layer. 3. The silicone-based oligomer 95 to 50 according to claim 1 or 2, wherein the release coating layer contains 2 to 20 functional groups consisting of an acryloyl group or a methacryloyl group in the molecule and has a number average molecular weight of 2,000 to 30,000. Weight part and number average molecular weight of 5 to 100 containing 3 to 20 functional groups in the molecule
A thermal printing pressure-sensitive adhesive sheet comprising a cured film obtained by treating 5 to 50 parts by weight of 5,000 silicone oligomers with ionizing radiation. 4. The thermal printing pressure-sensitive adhesive sheet according to claim 1, wherein the heat insulating sheet is a foam sheet having a thermal conductivity of 3.5 × 1/10 ⁴ cal / cmS ° C. or less.