JP2007017997A - Use method of non-contact type rewrite thermal label - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a use method of a non-contact rewrite thermal label which allows repeated recording and erasing of information by a non-contact method while the label is stuck to an adherend, and which is recyclable together with the adherend. <P>SOLUTION: The use method of a non-contact rewrite thermal label uses the following non-contact rewrite thermal label for repeatedly recording and erasing information by a non-contact system while the label is stuck to an adherend. The label comprises: layers including a thermosensitive color developing layer 3 containing a dye precursor and a reversible developer, successively deposited on one surface of a substrate 1; and a pressure-sensitive adhesive layer 5 applied on the other surface of the substrate. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a non-contact type rewrite thermal label. More specifically, the present invention is capable of repeatedly recording and erasing information by a non-contact method in a state of being attached to an adherend, and can also use a substrate having poor solvent resistance, and an adherend. In addition, the present invention relates to a method of using a non-contact type rewrite thermal label that can be recycled.

Labels currently used for the management of goods, such as labels attached to plastic containers that transport food, labels used for the management of electronic parts, logistics management labels attached to cardboard, etc. The mainstream is the use of thermal paper or the like as a surface substrate. This heat-sensitive recording material is provided with a heat-sensitive recording layer mainly comprising an electron-donating usually colorless or light-colored dye precursor and an electron-accepting developer on a support. By heating with, for example, the dye precursor and the developer react instantaneously to obtain a recorded image. In general, once such an image is formed, such a heat-sensitive recording material cannot be erased and returned to the state before image formation again.
Until now, in the label used for the above-mentioned article management, such a heat-sensitive recording material has been mainly used as a surface base material, and a contact-type thermal printer or the like is used for the destination, the sender, the article name, the quantity, the lot. Information such as numbers and the barcodes were printed and affixed to the adherend. When the role as a label is completed, it takes a lot of time and labor to manually peel off the label in order to reuse the container and cardboard as the adherend. Further, the adherend from which the label has been peeled off is affixed again with another label printed by a contact-type thermal printer or the like, and is used repeatedly.
Thus, every time the adherend is repeatedly used, the label is peeled off and pasted, and the label is stuck to the adherend without being peeled off from the adherend each time. Thus, a rewrite thermal label capable of repeatedly recording and erasing information is expected.
On the other hand, in recent years, a reversible thermosensitive recording material capable of forming and erasing an image, for example, (1) a thermosensitive layer comprising a low molecular weight organic substance whose transparency reversibly changes depending on temperature and a resin is provided on a support. (2) a reversible thermosensitive recording material in which a thermosensitive coloring layer containing a dye precursor and a reversible developer is provided on a support has been developed.
When such a reversible thermosensitive recording material is applied to the rewritable thermal label, it is required to record and erase information by a non-contact method in order to record and erase information with the label attached to the adherend. Therefore, the reversible thermosensitive recording material (2) is preferable.
However, in the reversible thermosensitive recording material (2), a dye precursor, a reversible developer, and other additives used as necessary are usually used in a solvent such as tetrahydrofuran to form a thermosensitive coloring layer. A coating solution obtained by dissolving or dispersing the components is used. Accordingly, polystyrene, acrylonitrile-butadiene-styrene copolymer (ABS resin), polycarbonate films, etc., which are currently used as mainstream labels, are difficult to use because of their poor solvent resistance. Only solvent-soluble polyethylene terephthalate, polypropylene film, and the like can be used, and there is a problem that the type is unavoidable. In order to use the resin film, which is currently used in the mainstream, as a label substrate, it is necessary to take measures to improve resistance to solvents.
Further, when the non-contact method is adopted by applying the reversible thermosensitive recording material of (2) above, since laser light is usually used for information recording, the laser light is absorbed and heat exchange is efficiently performed. It is important to add functions.
Furthermore, in recent years, plastic containers that are used adherends are required to be recycled in order to build a resource recycling society. When recycling a plastic container or the like, the rewritable thermal label is preferably one that can be recycled together with the adherend while being attached to the adherend.
JP 2001-88443 A JP 2001-71543 A Japanese Patent Application Laid-Open No. 11-58963 Japanese Patent Laid-Open No. 7-172054 JP 2000-309169 A

  Under such circumstances, the present invention can repeatedly record and erase information by a non-contact method in a state of being attached to an adherend, and can use a substrate having poor solvent resistance. In addition, the present invention has been made for the purpose of providing a method of using a non-contact type rewritable thermal label that can be recycled together with an adherend.

As a result of intensive studies to develop the non-contact type rewritable thermal label having the above-mentioned excellent function, the present inventors have found that the purpose can be achieved by a label having a specific laminated structure. Based on this, the present invention has been completed.
That is, the present invention
(1) A heat-sensitive color-developing layer containing a dye precursor and a reversible developer is laminated on one surface of a substrate in order from the substrate side, and a pressure-sensitive adhesive layer is applied to the other surface of the substrate. A method of using a non-contact type rewrite thermal label, which is used for repeatedly recording and erasing information in a non-contact manner with the contact type rewrite thermal label being attached to an adherend,
(2) A thermosensitive coloring layer containing an anchor coat layer, a dye precursor and a reversible developer is laminated on one surface of the substrate in this order from the substrate side, and an adhesive layer is formed on the other surface of the substrate. A method of using a non-contact type rewrite thermal label used for repeatedly recording and erasing information in a non-contact manner with the non-contact type rewrite thermal label applied to the adherend,
(3) As a means for non-contact type recording, a method for using the non-contact type rewritable thermal label according to (1) or (2), wherein visible information is recorded or rewritten using laser light during recording,
(4) A method of using the non-contact type rewritable thermal label according to (1), (2) or (3), wherein the oscillation wavelength of the laser beam is 700 to 1500 nm,
(5) A method of using the non-contact type rewritable thermal label according to any one of (1) to (4), wherein the light absorption heat conversion agent is contained in the heat-sensitive color developing layer or laminated on the upper layer thereof, and (6) The method for using the non-contact type rewrite thermal label according to any one of (1) to (5), wherein the information is erased by a non-contact type heating method in which the erasing means when rewriting information is hot air blowing
Is to provide.
As a preferred embodiment,
(7) The method for using the non-contact type rewritable thermal label according to (1), wherein the crosslinked resin in the anchor coat layer has a degree of crosslinking of a gel fraction of 30% or more,
(8) The method for using the non-contact type rewritable thermal label according to (1) or (2), wherein the thermosensitive coloring layer contains a dye precursor and a reversible developer.
(9) The method of using the non-contact type rewritable thermal label according to any one of (1) to (3), wherein the light absorption heat exchange layer contains a light absorber composed of an organic dye and / or an organometallic pigment, And (10) The method of using the non-contact type rewritable thermal label according to any one of (1) to (4), wherein the base material is the same material as the material of the adherend.
Can be mentioned.

According to the present invention, it is possible to repeatedly record and erase information by a non-contact method in a state of being attached to an adherend, and a substrate having poor solvent resistance can be used and recycled together with the adherend. It is possible to provide a method of using a non-contact type rewritable thermal label that can be used.
The non-contact type rewritable thermal label of the present invention is suitably used as, for example, a label attached to a plastic container (return box) for transporting foods, a label used for managing electronic parts, a logistics management label attached to cardboard or the like.

There is no restriction | limiting in particular as a base material in the non-contact-type rewritable thermal label of this invention, What is excellent in solvent resistance, and a thing with poor solvent resistance etc. can be used. Specifically, plastic films such as polystyrene, ABS resin, polycarbonate, polypropylene, polyethylene, polyethylene terephthalate, synthetic paper, nonwoven fabric, paper, and the like can be given. The base material is preferably the same material as the material of the adherend because it can be recycled together with the adherend. Although there is no restriction | limiting in particular as thickness of a base material, Usually, 10-500 micrometers, Preferably it is the range of 20-200 micrometers.
If a plastic film is used as the base material, surface treatment may be applied by an oxidation method or an unevenness method, if desired, for the purpose of improving the adhesion with an anchor coat layer or an adhesive layer provided on the surface. Can do. Examples of the oxidation method include corona discharge treatment, chromic acid treatment (wet), flame treatment, hot air treatment, ozone / ultraviolet irradiation treatment and the like, and examples of the unevenness method include sand blast method and solvent treatment method. Is mentioned. These surface treatment methods are appropriately selected depending on the type of the substrate, but in general, the corona discharge treatment method is preferably used from the viewpoints of effects and operability.
It is also effective to use a foam film having a high heat insulation effect as a base material in order to effectively use the conversion heat when recording information by laser light. Further, as the base material, a plastic film is preferable, but a paper base material can be preferably used as long as the number of repeated use is small.

In the rewritable thermal label of the present invention, an anchor coat layer is provided on one surface of the substrate. This anchor coat layer is for protecting the substrate from the solvent in the coating liquid used when the heat-sensitive color developing layer in the next step is provided. By providing this anchor coat layer, the solvent resistance is poor. A substrate can also be used.
There is no restriction | limiting in particular as resin which comprises this anchor coat layer, Although various things can be used, In this invention, crosslinked resin excellent in solvent resistance is used. Examples of the cross-linked resin include cross-linked acrylic resin, polyester resin, polyurethane resin, and ethylene-vinyl acetate copolymer. When using a substrate having poor solvent resistance, it is preferable to use a coating solution that is not an organic solvent type, such as an aqueous solution type or a water dispersion type coating solution, for forming the anchor coat layer. Moreover, there is no restriction | limiting in particular as a crosslinking method, According to the kind of resin to be used, it can select suitably from conventionally well-known various methods.
Furthermore, it is also effective to use a resin that crosslinks and cures with ionizing radiation such as ultraviolet rays and electron beams as a solventless type. This ionizing radiation curable resin can easily adjust the degree of crosslinking by changing the irradiation dose, and can form a crosslinked resin having a high crosslinking density.
In the present invention, the degree of crosslinking of the crosslinked resin forming the anchor coat layer is preferably 30% or more, more preferably 40% or more, in terms of gel fraction measured by the following method. If the gel fraction is less than 30%, the solvent resistance is insufficient, and the base material cannot be sufficiently protected from the solvent in the coating liquid when forming the thermosensitive coloring layer in the next step. There is a fear.

<Method for measuring gel fraction>
On the release film, an anchor coat layer-forming coating solution is applied and crosslinked under the same conditions as in forming the anchor coat layer in the present invention, and then the crosslinked resin (50 mm × 100 mm) is peeled off from the release film. . Next, the above two cross-linked resins (total weight Ag) are wrapped on a 100 × 130 mm size 200 mesh gold steel with a wire mesh, set in a Soxhlet extractor, and extracted for 5 hours under reflux of tetrahydrofuran. . Next, after the extraction treatment, the resin remaining on the wire mesh is dried at 100 ° C. for 24 hours, and after conditioning in an atmosphere of 23 ° C. and 50% RH for 3 hours or more, the weight of the resin is measured (Bg), Gel fraction (%) = (B / A) × 100
To calculate the gel fraction.
The thickness of the anchor coat layer is usually in the range of 0.1 to 30 μm, preferably 1 to 15 μm.

In the rewritable thermal label of the present invention, a thermosensitive coloring layer is provided on the anchor coat layer thus formed. This heat-sensitive color developing layer is generally composed of a colorless or light dye precursor, a reversible developer, a binder used as necessary, a decoloring accelerator, an inorganic pigment, various additives, and the like.
There is no restriction | limiting in particular as said dye precursor, Arbitrary things can be suitably selected and used from the well-known compound used as a dye precursor in the conventional heat-sensitive recording material. For example, 3,3-bis (4-dimethylaminophenyl) -6-dimethylaminophthalide, 3- (4-dimethylaminophenyl) -3- (1,2-dimethylindol-3-yl) phthalide, 3- ( Triarylmethane compounds such as 4-diethylamino-2-ethoxyphenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide, rhodamine B anilinolactam, 3- (N-ethyl) Xanthene compounds such as -N-tolyl) amino-6-methyl-7-anilinofluorane, diphenylmethane compounds such as 4,4'-bis (dimethylaminophenyl) benzhydrylbenzyl ether, N-chlorophenylleucooramine Compounds, spiro compounds such as 3-methylspirodinaphthopyran, 3-ethylspirodinaphthopyran, benzoylleucomet Nburu, p- nitrobenzoyl leuco methylene blue, etc. may be used to select one from among such thiazine-based compounds may be used in combination to select two or more.

On the other hand, the reversible developer is not particularly limited as long as it causes a reversible color change in the dye precursor due to the difference in the cooling rate after heating. From the viewpoint of repeated durability, an electron-accepting compound composed of a phenol derivative having a long-chain alkyl group is preferable.
The phenol derivative may have an atom such as oxygen or sulfur or an amide bond in the molecule. The length and number of alkyl groups are selected in consideration of the balance between decoloring properties and color developability, but the alkyl groups are preferably those having 8 or more carbon atoms, particularly those having about 8 to 24 carbon atoms. In addition, hydrazine compounds, anilide compounds, urea compounds having a long-chain alkyl group in the side chain can also be used.
Examples of the phenol derivative having such a long-chain alkyl group include 4- (N-methyl-N-octadecylsulfonylamino) phenol, N- (4-hydroxyphenyl) -N′-n-octadecylthiourea, N- (4-hydroxyphenyl) -N′-n-octadecylurea, N- (4-hydroxyphenyl) -N′-n-octadecylthioamide, N- [3- (4-hydroxyphenyl) propiono] -N′-octa Examples include decanohydrazide, 4′-hydroxy-4-octadecylbenzanilide.
Utilizing the crystallinity of such a reversible developer, when recording information, it is rapidly cooled after heating. Recording and erasing are possible.

Examples of the binder used as necessary for the purpose of maintaining each component constituting the thermosensitive coloring layer and maintaining uniform dispersibility include polyacrylic acid, polyacrylic acid ester, polyacrylamide, and polyvinyl acetate. And polymers such as polyurethane, polyester, polyvinyl chloride, polyethylene, polyvinyl acetal, and polyvinyl alcohol, and copolymers thereof.
Further, as a decoloring accelerator used as necessary, for example, ammonium salts and the like, as inorganic pigments, for example, talc, kaolin, silica, titanium oxide, zinc oxide, magnesium carbonate, aluminum hydroxide, and the like are added. Examples of the agent include known leveling agents and dispersants.

In order to form the thermosensitive coloring layer, first, a coating liquid is prepared by dissolving or dispersing the dye precursor, the reversible developer, and various additive components used as necessary in an appropriate organic solvent. . In this case, for example, alcohols, ethers, esters, aliphatic hydrocarbons, and aromatic hydrocarbons can be used as the organic solvent. Tetrahydrofuran is particularly preferable because of its excellent dispersibility. Although there is no restriction | limiting in particular about the ratio of a dye precursor and a reversible developer, A reversible developer is 50-700 weight part normally with respect to 100 weight part of dye precursors, Preferably it is 100-500 weight part. Used in a range.
Next, the coating liquid prepared in this manner is applied onto the undercoat layer by a conventionally known means, and dried to form a thermosensitive coloring layer. Although there is no restriction | limiting in particular about drying process temperature, It is desirable to dry at low temperature so that a dye precursor may not color. The thickness of the thermosensitive coloring layer thus formed is usually in the range of 1 to 10 μm, preferably 2 to 7 μm.
In the rewritable thermal label of the present invention, a light-absorbing heat conversion layer is provided on the heat-sensitive color forming layer thus formed. This light absorption heat conversion layer is generally composed of a light absorber, a binder, an inorganic pigment used as necessary, an antistatic agent, and other additives.
The light absorber has a function of absorbing the laser light to be irradiated and converting it into heat, and is appropriately selected depending on the laser light to be used. As the laser beam, it is preferable to select a laser beam having an oscillation wavelength in the range of 700 to 1500 nm from the viewpoint of the simplicity of the apparatus and the scanning property. For example, a semiconductor laser beam and a YAG laser beam are preferable.
The light absorber preferably absorbs near-infrared laser light and generates heat, and does not absorb much light in the visible light region. Visibility and bar code readability are reduced when visible light is absorbed. Examples of light absorbers that satisfy such required performance include organic dyes and / or organometallic dyes. Specifically, at least one selected from cyanine dyes, phthalocyanine dyes, anthraquinone dyes, azulene dyes, squarylium dyes, metal complex dyes, triphenylmethane dyes, indolenine dyes, and the like. Can be mentioned. Of these, indolenine dyes are preferred because of their high photothermal exchange properties.

On the other hand, as the binder, the same materials as those exemplified as the binder in the heat-sensitive coloring layer can be used. However, since the light-absorbing heat conversion layer is the outermost layer of the label, the color development in the lower layer is visible. Transparency and surface hard coat properties (abrasion resistance) are required. Therefore, as the binder, a cross-linked resin is preferable, and an ionizing radiation curable resin such as an ultraviolet ray or an electron beam is particularly preferable.
In order to form this light-absorbing heat conversion layer, first, a coating liquid containing the light-absorbing agent, binder and various additives used as necessary is prepared. At this time, depending on the type of the binder, an appropriate organic solvent may be used as necessary. Although there is no restriction | limiting in particular about the ratio of a binder and a light absorber, A light absorber is normally used in 0.01-50 weight part with respect to 100 weight part of binder, Preferably it is 0.03-10 weight part. . However, since the light absorber may also absorb light in the visible light region, the surface may be colored when the amount of the light absorber is large. If the surface is colored, not only the appearance of the label, but also the visibility of information and the readability of barcodes, etc., will be reduced. Is preferred.

Next, the coating solution thus prepared is coated on the thermosensitive coloring layer by a conventionally known means, and after drying treatment, it is crosslinked by heating, irradiation with ionizing radiation, etc., thereby absorbing light. A heat conversion layer is formed. The thickness of the light absorption heat conversion layer thus formed is usually 0.05 to 10 μm, preferably 0.1 to 3 μm.
In the rewritable thermal label of the present invention, a pressure-sensitive adhesive layer is provided on the surface of the substrate opposite to the respective layers. The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer has a resin composition that exhibits good adhesion to an adherend made of plastic and that does not inhibit this recycling when the adherend and the label are recycled together. In particular, a pressure-sensitive adhesive containing an acrylic ester copolymer as a resin component is preferable because of its excellent recyclability. In addition, rubber-based, polyester-based, polyurethane-based adhesives, and the like can also be used. Silicone-based adhesives with excellent heat resistance can also be used, but because the compatibility with the adherend is poor in the recycling process, the recycled resin tends to be non-uniform, causing strength reduction and poor appearance. May be.
In addition, this adhesive may be any of emulsion type, solvent type, and solventless type, but the cross-linked type is superior in water resistance in the washing process applied for repeated use of the adherend, and the label. This is preferable because durability of holding is also improved. The thickness of the pressure-sensitive adhesive layer is generally 5 to 60 μm, preferably 15 to 40 μm.

In the rewritable thermal label of the present invention, a release sheet can be provided on the pressure-sensitive adhesive layer as necessary. As the release sheet, a plastic film such as polyethylene terephthalate (PET), foamed PET, or polypropylene, polyethylene laminated paper, glassine paper, clay coat paper, or the like is used. The release agent is preferably a silicone-based one, and other fluorine-based or long-chain alkyl group-containing carbamate-based ones can also be used. The application thickness of the release agent is usually in the range of 0.1 to 2.0 μm, preferably 0.5 to 1.5 μm. Moreover, although there is no restriction | limiting in particular about the thickness of a peeling sheet, Usually, it is about 20-150 micrometers.
As the formation order of each layer in the rewritable thermal label of the present invention, an anchor coat layer, a thermosensitive coloring layer and a light absorption heat conversion layer are provided in this order on one surface of the substrate, and then on the opposite surface of the substrate. It is preferable to provide an adhesive layer.
The anchor coat layer, thermosensitive coloring layer, and light absorption heat conversion layer can be applied to the respective coating liquids such as direct gravure, gravure reverse, micro gravure, Meyer bar, air knife, blade, die, roll knife, reverse, curtain coat, etc. The film can be formed by coating, drying, and further heating if necessary, using a coating method such as flexographic printing, letter press, or screen printing. In particular, the thermosensitive coloring layer is desirably dried at a low temperature so as not to develop color. In the case of an ionizing radiation curable type, it is cured by irradiation with ionizing radiation.

On the other hand, the pressure-sensitive adhesive layer may be formed by directly applying and drying the pressure-sensitive adhesive on the substrate surface by a known method such as a roll knife coater, reverse coater, die coater, gravure coater, Meyer bar, or the like. The pressure-sensitive adhesive layer may be transferred by applying the pressure-sensitive adhesive on the release surface of the release sheet by the above method and drying to provide a pressure-sensitive adhesive layer, and then sticking it to the substrate. The latter transfer method is preferable because the drying efficiency of the pressure-sensitive adhesive can be increased without causing color development of the thermosensitive coloring layer provided on the substrate.
FIG. 1 is a cross-sectional view showing an example of the configuration of the non-contact type rewrite thermal label of the present invention. The non-contact type rewritable thermal label 10 has an anchor coat layer 2, a heat-sensitive color developing layer 3 and a light absorption heat conversion layer 4 sequentially laminated on one side of the substrate 1, and the other side of the substrate 1 on the opposite side. The adhesive layer 5 and the release sheet 6 are sequentially provided on the surface (back surface).
Next, an example of an embodiment when using the non-contact type rewrite thermal label of the present invention will be described.

First, before applying the label of the present invention to an adherend, desired information is recorded (printed) on the label. In this case, a contact method in which a thermal head is brought into contact with the light absorption heat conversion layer may be employed, or a non-contact method using laser light may be employed. How to do will be described.
In this non-contact method, laser light is irradiated in a non-contact state on the label surface, the laser light is absorbed by the light absorbent in the light absorption heat conversion layer on the label surface, and converted into heat, Printing is performed by the dye precursor in the lower thermosensitive coloring layer reacting with the reversible developer to cause coloration of the dye precursor. As the laser light to be used, semiconductor laser light and YAG laser light having an oscillation wavelength of 700 to 1500 nm as described above are preferable.
The distance between the label surface and the laser light source varies depending on the irradiation output, but is preferably in the range of 1 μm to 30 cm. A shorter distance is preferable on the laser light output surface and scanning surface. Further, it is preferable on the image forming surface that the beam diameter of the laser light is condensed to about 1 to 50 μm on the label surface. The faster the scanning speed, the shorter the recording time, which is advantageous, but 3 m / second or more is particularly desirable. The output of the laser may be 50 mW or more, but about 300 to 10,000 mW is practically preferable for increasing the printing speed. In order to temporarily fix the label, the surface opposite to the laser light irradiation side of the label is temporarily fixed electrostatically using a drum roll or the like, or temporarily fixed by suction or the like.

Thus, after irradiating with a laser beam, an image can be obtained by quenching with cooling air. If the image is naturally cooled without being rapidly cooled, the image density is lowered or the color is erased. This cooling operation may be performed alternately with the scanning of the laser beam or may be performed simultaneously. In order to stabilize the image, it is important to lower the surface temperature by this rapid cooling.
Thus, the label which recorded information is affixed on a to-be-adhered body manually by a machine or a person. When the machine is attached, a grid crimping method, a roller plunger method for crimping with a roll, an air blowing method with air, or the like can be employed.
The adherend to which the label is attached in this manner is cleaned as necessary for reuse, after fulfilling the purpose of transporting the article. As a cleaning method, a method of removing dust by blowing air, a method of washing with water, a method of cleaning with alkaline hot water, and the like are used.
In order to use the used adherend again, it is necessary to rewrite the information on the attached label into new information. In this case, first, heat is applied to the label on the adherend. As this heat, a temperature in the range of about 50 to 180 ° C., preferably 80 to 150 ° C. is advantageous. This temperature can be changed by a reversible developer or a decoloring accelerator in the thermosensitive coloring layer. As a heating method, a method in which a hot roll or the like is brought into contact, a method in which hot air is blown, a method by laser light irradiation, or the like can be used. After heating, the information is erased by slowly cooling the label with natural cooling or hot air.

Next, after erasing information in this way, new information is recorded by the non-contact method described above. Thus, the adherend and the label can be repeatedly used by repeating the above steps.
In the present invention, the number of repetitions can be about 10 to 500 times. The adherend and the label that have been used a predetermined number of times are sent to the recycling process together and recycled. Conventionally, when the adherend is recycled, the label becomes a foreign substance, and the strength of the recycled product is reduced. Therefore, it has been necessary to peel off the label and remove it. Further, since conventional heat-sensitive color formers develop color by heat and become soiled, it has been impossible to recycle the label together with the adherend. On the other hand, the label of the present invention is different from the conventional thermosensitive coloring system, and can be recycled together with the adherend by making the base material of the label the same as the material of the adherend. It becomes.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
The degree of cross-linking of the resin in the anchor coat layer was expressed as a gel fraction measured according to the method described in the specification.
Preparation Example 1 Preparation of Coating Liquid (Liquid A) for Formation of Thermosensitive Coloring Layer 3- (4-Diethylamino-2-ethoxyphenyl) -3- (1-ethyl-2) which is a triarylmethane compound as a dye precursor -Methylindol-3-yl) -4-azaphthalide 10 parts by weight, 30 parts by weight of 4- (N-methyl-N-octadecylsulfonylamino) phenol as a reversible developer, 1.5 parts by weight of polyvinyl acetal as a dispersant Then, 2500 parts by weight of tetrahydrofuran was pulverized and dispersed by a pulverizer and a disper to prepare a coating solution for forming a thermosensitive coloring layer (liquid A).
Preparation Example 2 Preparation of Coating Liquid for Forming Light Absorption Heat Conversion Layer (Liquid B) Light Absorption Heat Conversion Agent (Indolenine Dye) [manufactured by Nippon Coloring Dye Company, trade name “NK-2014”] 5 parts by weight, ultraviolet light Curing type binder (urethane acrylate) [manufactured by Dainichi Seika Kogyo Co., Ltd., trade name “PU-5 (NS)”] 100 parts by weight and inorganic pigment (silica) [manufactured by Nippon Aerosil Kogyo Co., Ltd., trade name “Aerosil R-972” ]] 3 parts by weight were dispersed with a disper to prepare a light-absorbing heat conversion layer forming coating liquid (liquid B).
Example 1
100 parts by weight of an acrylic copolymer emulsion [made by Shin-Nakamura Chemical Co., Ltd., trade name “New Coat TS-1016”] and 2 parts by weight of an epoxy-based crosslinking agent [trade name “E-104” made by Syden Chemical Co., Ltd.] An acrylic emulsion type cross-linking type anchor coating layer forming coating solution (C-1 solution) was prepared.
The C-1 solution is applied by direct gravure method on one side of a base film made of an ABS film [trade name “PSZ980” manufactured by Shin-Etsu Polymer Co., Ltd.] with a thickness of 80 μm so that the thickness after drying becomes 3 μm And dried in an oven at 60 ° C. for 3 minutes to form an anchor coat layer. The gel fraction of the crosslinked resin in this anchor coat layer was 52%.
On this anchor coat layer, the solution A obtained in Preparation Example 1 was applied by a gravure method so as to have a dry thickness of 4 μm, and dried in an oven at 60 ° C. for 5 minutes to form a thermosensitive coloring layer. Next, the liquid B obtained in Preparation Example 2 is applied on the thermosensitive coloring layer by a flexo method so that the thickness after drying becomes 1.2 μm, and ultraviolet light is irradiated to form a light absorption heat conversion layer. The label member was formed.
In addition, when apply | coating A liquid on an anchor coat layer, it was observed visually whether a base film melt | dissolves with a coating liquid.
A silicone resin obtained by adding a catalyst to a 50 μm-thick PET film [trade name “Lumirror T type” manufactured by Toray Industries, Inc., product name “SRX-211” manufactured by Toray Dow Corning Co., Ltd.] It was applied so that the thickness was 0.7 μm and dried to prepare a release sheet. On the silicone resin coated surface of the release sheet, 100 parts by weight of an acrylic pressure-sensitive adhesive [manufactured by Toyo Ink Manufacturing Co., Ltd., trade name “BPS-1109”] and a crosslinking agent [manufactured by Nippon Polyurethane Co., Ltd., trade name “Coronate L”] 3 weights The pressure sensitive adhesive coating liquid is added by a roll knife coater method so that the thickness after drying is 30 μm, dried in an oven at 60 ° C. for 5 minutes, and then the laminator The back of the film was pasted and wound up to obtain a label roll. Next, slitting was performed on a roll having a width of 100 mm with a slitter to produce a 100 mm × 100 mm label, which was used as a printing sample.
For printing, a semiconductor laser (830 nm) irradiator with an output of 500 mW is focused so that the beam diameter is 12 μm on the label surface, and laser light is irradiated at a distance of 100 mm so that the applied energy is 1300 mJ / cm. Was done. Immediately after printing, cold air was blown to maintain the printed image.
After printing, the label was affixed to an ABS case as an adherend. After leaving for 7 days, 130 ° C. hot air was blown for 20 seconds, and then naturally cooled in a room temperature environment to erase the print.
After repeating the above printing and erasing 10 times, the following recycling test was conducted.
<Recycling test>
The adherend to which the label is attached at a volume ratio of 1% is melted at a temperature of 240 ° C., and then molded again to measure the following mechanical properties and evaluate the appearance as a recycled ABS film. Evaluated. The tensile strength was measured according to ASTM D638, the elongation was measured according to ASTM D638, and the Izod impact strength was measured according to ASTM D256.
The above results are shown in Table 1.
Example 2
In Example 1, it carried out like Example 1 except having changed the coating liquid (C-1 liquid) for anchor coat layer formation into the following C-2 liquid. The results are shown in Table 1.
<Preparation of anchor coat layer forming coating solution (C-2 solution)>
Polyester containing 100 parts by weight of a polyester resin aqueous solution [manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name “Polyester WR-961”] and 2 parts by weight of an epoxy-based cross-linking agent [trade name “E-104” produced by Syden Chemical Co., Ltd.] An aqueous solution type cross-linking type anchor coating layer forming coating solution (C-2 solution) was prepared.
The gel fraction of the crosslinked resin in the anchor coat layer was 42%.
Example 3
In Example 1, a coating solution for forming an anchor coat layer (C-1 solution) is a heat self-crosslinking polyurethane aqueous solution comprising a polyurethane resin aqueous solution [Daiichi Kogyo Seiyaku Co., Ltd.] and a trade name “Elastoron H38”. This was carried out in the same manner as in Example 1 except that the coating liquid for anchor coat layer formation was changed. The results are shown in Table 1.
The gel fraction of the crosslinked resin in the anchor coat layer was 59%.
Comparative Example 1
In Example 1, it carried out like Example 1 except not having provided an anchor coat layer. The results are shown in Table 1.
Comparative Example 2
In Example 1, it carried out similarly to Example 1 except not having used a crosslinking agent for preparation of the coating liquid for anchor-coat layer formation (C-1 liquid). The results are shown in Table 1.
Comparative Example 3
In Example 1, as a label member, a conventionally used thermal paper that cannot be rewritten [manufactured by Nippon Paper Industries Co., Ltd., trade name “TL69KS”] was used, and thereafter, the same process as in Example 1 was performed. The results are shown in Table 1.

  In Examples 1 to 3, the formation of the heat-sensitive coloring layer was good, re-recording was possible, the label peeling operation for recycling was unnecessary, and the recyclability was good. On the other hand, since the anchor coat layer was not provided in Comparative Example 1, the formation of the thermosensitive coloring layer was poor. In Comparative Example 2, since the anchor coat layer was a non-crosslinked resin, the formation of the thermosensitive coloring layer was poor. Since the comparative example 3 was recycled with the label using the conventional thermal paper attached to the adherend, the strength of the recycled film was reduced and the appearance was poor. Further, the label using the conventional thermal paper of Comparative Example 3 can be printed only once.

  The present invention is a method of using a non-contact type rewritable thermal label. In particular, the present invention is an application in which information can be repeatedly recorded and erased by a non-contact method in a state of being attached to an adherend, and is used even when a substrate having poor solvent resistance is used as a material. Moreover, it is industrially superior in that it can be used as a non-contact type rewritable thermal label that can be recycled together with the adherend.

FIG. 1 is a cross-sectional view showing an example of the configuration of the non-contact type rewrite thermal label of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base material 2 Anchor coat layer 3 Thermosensitive coloring layer 4 Light absorption heat conversion layer 5 Adhesive layer 6 Release sheet

Claims (6)

  Non-contact type rewrite in which a heat-sensitive coloring layer containing a dye precursor and a reversible developer is laminated on one surface of a substrate in order from the substrate side, and an adhesive layer is applied to the other surface of the substrate A method of using a non-contact type rewritable thermal label, which is used for repeatedly recording and erasing information in a non-contact manner with the thermal label attached to an adherend.   A thermosensitive coloring layer containing an anchor coat layer, a dye precursor and a reversible developer was laminated on one surface of the substrate in this order from the substrate side, and an adhesive layer was applied to the other surface of the substrate. A method of using a non-contact type rewritable thermal label that is used for repeatedly recording and erasing information in a non-contact manner with the non-contact type rewritable thermal label attached to an adherend.   The method of using a non-contact type rewritable thermal label according to claim 1 or 2, wherein visible information is recorded or rewritten using laser light during recording as means for non-contact type recording.   4. The method of using a non-contact type rewritable thermal label according to claim 1, wherein the laser light has an oscillation wavelength of 700 to 1500 nm.   The method for using a non-contact type rewritable thermal label according to any one of claims 1 to 4, wherein the light absorption heat conversion agent is contained in the heat-sensitive coloring layer or laminated on the upper layer thereof.   The method for using a non-contact type rewrite thermal label according to any one of claims 1 to 5, wherein the information is erased by a non-contact type heating method in which an erasing means for rewriting information is hot air blowing.

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