TAPE FOR LABEL WRITER

Abstract

To prevent an ink from discoloring and an ink from remaining when a tape for label writer using a transparent synthetic resin film which is colorized by an ink layer is peeled off from an adherend.

A tape for label writer being composed of: (i) the tape for label writer having a layer structure including at least a process layer, substrate layer, ink layer, barrier layer, and adhesive layer in this order; (ii) the substrate layer being a synthetic resin film; and (iii) the ink layer including one adhesive resin selected from the group including polyurethane resin, acrylic resin and polyester resin, and a pigment.

Claims

1. A tape for label writer, wherein: (i) the tape for label writer has a layer structure comprising at least a process layer, a substrate layer, an ink layer, a barrier layer, and an adhesive layer in this order; (ii) the substrate layer is a synthetic resin film; and (iii) the ink layer comprises one adhesive resin selected from the group including polyurethane-based resin, acryl-based resin and polyester-based resin, and a pigment.

2. The tape for label writer according to claim 1, wherein the layer structure is a layer structure comprising at least a process layer, a substrate layer, an ink layer, a barrier layer, an adhesive layer, and a separator layer in this order.

3. The tape for label writer according to claim 1, wherein the barrier layer comprises two or more layers.

4. The tape for label writer according to claim 1, wherein the acryl-based resin is an acrylic elastomer.

5. The tape for label writer according to claim 1, wherein the barrier layer comprises a polyester film.

6. The tape for label writer according to claim 1, wherein thickness of the barrier layer is 1 μm to 70 μm.

7. The tape for label writer according to claim 1, wherein thickness of the substrate layer is 5 μm to 300 μm.

8. The tape for label writer according to claim 1, wherein ratio of thickness of the substrate layer to thickness of the barrier layer is the substrate layer:barrier layer=3:1 to 1:1.

9. The tape for label writer according to claim 2, wherein the barrier layer comprises two or more layers.

10. The tape for label writer according to claim 2, wherein the acryl-based resin is an acrylic elastomer.

11. The tape for label writer according to claim 3, wherein the acryl-based resin is an acrylic elastomer.

12. The tape for label writer according to claim 2, wherein the barrier layer comprises a polyester film.

13. The tape for label writer according to claim 3, wherein the barrier layer comprises a polyester film.

14. The tape for label writer according to claim 4, wherein the barrier layer comprises a polyester film.

15. The tape for label writer according to claim 2, wherein thickness of the barrier layer is 1 μm to 70 μm.

16. The tape for label writer according to claim 3, wherein thickness of the barrier layer is 1 μm to 70 μm.

17. The tape for label writer according to claim 4, wherein thickness of the barrier layer is 1 μm to 70 μm.

18. The tape for label writer according to claim 5, wherein thickness of the barrier layer is 1 μm to 70 μm.

19. The tape for label writer according to claim 6, wherein thickness of the substrate layer is 5 μm to 300 μm.

20. The tape for label writer according to claim 19, wherein ratio of thickness of the substrate layer to thickness of the barrier layer is the substrate layer:barrier layer=3:1 to 1:1.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0033] FIG. 1 is a cross-sectional view of a tape for label writer of the present invention having a five-layered structure.

[0034] FIG. 2 is a cross-sectional view of a tape for label writer of the present invention having a six-layered structure.

DESCRIPTION OF EMBODIMENTS

[0035] A tape for label writer of the present invention includes at least a process layer, a substrate layer, an ink layer, a barrier layer, and an adhesive layer. A separator layer may be included as needed.

1. Process Layer

[0036] The tape for label writer of the present invention contains a process layer for conducting printing on a substrate layer. The process layer is provided on the printed side of the substrate layer.

[0037] The process layer varies depending on whether printing is based on an ink ribbon printing system (heat transfer) or an inkjet printing system. In the ink ribbon printing system (heat transfer), the substrate layer is subjected to a coating process for enabling printing with the use of an ink ribbon, and an adhesive resin is used as a processing agent to which both of the substrate layer and ink ribbon are easy to attach. Examples of the adhesive resin include polyester resin and polyurethane resin. A solution of such resin in an organic solvent is applied to form the process layer. As the organic solvent, toluene or methyl ethyl ketone is known. In this case, applying and drying are often performed to form the process layer.

[0038] The amount of coating after the drying in the ink ribbon printing system (heat transfer) is generally around 0.10 to around 0.50 g/m.sup.2.

[0039] In an inkjet printing system, because ink is sprayed, a process layer for absorbing the ink is provided on the substrate layer. Examples of an ink-absorbent processing agent include a processing agent that contains a water-soluble polymer such as polyvinyl alcohol, polyvinylpyrrolidone or gelatin as the main component; a processing agent that contains a water-soluble polymer into which fine particles such as silica, alumina, glass beads or synthetic resin microbeads are incorporated; and a processing agent that contains a superabsorbent polymer as the main component. In addition, in order to provide water resistance, there is a method for providing a high molecular porous layer, and forming a film by heat treatment. Furthermore, the process layer may be used as a process layer for a nonaqueous inkjet ink, instead of an aqueous inkjet ink.

[0040] The amount of coating on the process layer for an inkjet ink after drying is generally around 0.50 to around 1.5 g/m.sup.2. The process layer may be composed of two or more layers.

2. Substrate Layer

[0041] A synthetic resin film is used as the substrate layer. In particular, the synthetic resin film preferably includes a transparent synthetic resin film, which includes a synthetic resin film made of polyethylene, polypropylene, polyvinyl chloride, polyester, polycarbonate, or the like.

[0042] The thickness of the substrate layer is usually 5 μm to 300 μm, preferably 7 μm to 200 μm, more preferably 9 μm to 100 μm, still more preferably 10 μm to 50 μm, particularly preferably 12 μm to 25 μm, most preferably 13 μm to 23 μm. In case where the substrate layer is too thick, the substrate layer becomes easy to peel off when attached to curved surfaces. In addition, in case where the substrate layer is too thin, the productivity is damaged because of insufficient tension in a production process. Furthermore, there exist two layers of the substrate layer and the barrier layer, two layers of the substrate layer and the barrier layer being in a laminated state so as to sandwich the ink layer therebetween. Accordingly, when the thickness of the substrate layer increases such that the thickness of the substrate layer is beyond 23 μm, the attachment performance to curved surfaces may be slightly reduced, although there is no problem in a practical use. The substrate layer may be composed of two or more layers. In this case, the ink layer may be placed between the substrate layers, and thus the substrate layer/ink layer/substrate layer may be formed. Accordingly, when the substrate layer is composed of two layers, for example, the process layer/substrate layer/ink layer/substrate layer/ink layer/barrier layer/adhesive layer may be formed.

3. Ink Layer

[0043] The ink layer is provided on the substrate layer on the opposite side from the process layer.

[0044] The ink layer contains a pigment and adhesive resin. As the pigment, a publicly known pigment may be used, which is conventionally used in various kinds of fields. Specifically, an organic pigment such as a phthalocyanine-based-, azo-based-, condensed azo-based-, azo lake-based-, anthraquinone-based-, perylene/perinone-based-, indigo/thioindigo-based-, azomethineazo-based-, isoindoline-based-, dioxane-based-, quinacridone-based-, aniline black-based- or carbon black-based-pigment, or the like may be included. Further, titanium oxide-based-, iron oxide-based-, iron hydroxide-based-, chromium oxide-based-, chromic acid-based-, aluminum powder-based-, bronze powder-based organic pigment, or the like may be included. The pigment may be in any forms, or may be one which has been subjected to a distributed process based on various kinds of publicly known methods.

[0045] The adhesive resin includes polyurethane-based resin, polyester-based resin, or acryl-based resin. In other words, the adhesive resin may be one selected from the group including polyurethane-based resin, acryl-based resin, and polyester-based resin.

[0046] Especially, an acrylic elastomer is the most suitable as the acrylic resin.

[0047] Such an acrylic elastomer is generally a polymer having a polymethylene-based saturated chain formed of a polymer of ethyl acrylate or another acrylate, or a polymer having a polymethylene-typed saturated chain formed of a copolymer of ethyl or another acrylate and acrylonitrile. Furthermore, among such acrylic elastomers, an acrylic elastomer is desirable having a structure of block copolymer formed of methyl methacrylate and butyl acrylate. The mass-average molecular weight of the block copolymer formed of methyl methacrylate and butyl acrylate is preferably 60,000 to 100,000, more preferably 70,000 to 90,000. Examples thereof include KURARITY (registered trademark) LA2140e, LA2230, LA2250 and LA1114 made by Kuraray Co., Ltd. In this case, a plurality of acrylic elastomers may be blended. LA2140e made by Kuraray Co., Ltd. is particularly preferable.

[0048] When polyurethane resin is used as adhesive resin, a hardener may be used in the ink layer in combination. In this case, as the hardener, an isocyanate hardener is preferably used.

[0049] The ink layer is usually formed of a mixture of the pigment and the adhesive resin, in which the pigment accounts for 30% to 70% by mass, preferably 35% to 60% by mass, more preferably 40% to 55% by mass, with respect to 100% by mass of a total amount of the ink layer.

[0050] The thickness of the ink layer is usually 1 μm to 50 μm, preferably 5 μm to 30 μm, more preferably 7 μm to 25 μm. The ink layer may be composed of two or more layers.

4. Barrier Layer

[0051] In the present invention, a barrier layer is provided between the ink layer and the adhesive layer in order to inhibit the adhesive layer from being transferred into the ink layer. A synthetic resin film suitable for shutting off the adhesive layer may be used as the barrier layer, including a synthetic resin film formed of polyethylene, polypropylene, polyvinyl chloride, polyester, polycarbonate, or the like. Especially, a polyester film is preferable.

[0052] The barrier layer is required to have a sufficient thickness to inhibit the adhesive layer from being transferred into the ink layer, the thickness being usually 1 μm to 70 μm, preferably 5 μm to 50 μm, more preferably 9 μm to 30 μm, still more preferably 10 μm to 20 μm, or particularly preferably, in case of a polyester film, 11 μm to 15 μm. In case where the barrier layer is too thick, the tape becomes thick as a whole and thus easy to peel off when being attached to curved surfaces. In addition, in case where the barrier layer is too thin, the productivity is damaged because of insufficient tension in a production process. It is preferable for the barrier layer to be thinner than the substrate layer. The ratio of thickness of the substrate layer to the barrier layer is preferably the substrate layer:barrier layer=3:1 to 1:1, more preferably 2:1 to 6:5, still more preferably 9:5 to 3:2. The barrier layer may be composed of two or more layers.

5. Adhesive Layer

[0053] In general, an adhesive layer of an adhesive material is formed with the use of an adhesive exhibiting a pressure-sensitive adhesive property at room temperature. Examples of such an adhesive include an acryl-based adhesive, natural rubber-based adhesive, synthetic rubber-based adhesive, silicone-based adhesive, vinyl ester-based adhesive, vinyl ether-based adhesive, and urethane-based adhesive. Among them, an acrylic adhesive having good adhesiveness and weather-resistance is preferably used. In general, the monomeric unit of such an acrylic adhesive is (meth)acrylic acid alkyl ester as the main component.

[0054] The thickness of the adhesive layer is usually 3 μm to 150 μm, preferably 5 μm to 100 μm, more preferably 9 μm to 50 μm. The adhesive layer may be composed of two or more layers.

6. Separator Layer

[0055] The tape for label writer of the present invention is provided with, if necessary, a separator layer for protecting the adhesive layer or preventing deterioration. The separator layer is not limited in particular, but those may be used which are used under the general name of releasing paper, releasing film, peeling paper, peeling film, peeling liner, or the like. Specific examples thereof include a polyester film having a silicone-processed surface, paper having a silicone-processed surface, and a laminate of polyethylene and paper having a silicone-processed surface. The thickness of the separator layer is usually around 10 μm to around 300 μm.

7. Layer Structure

[0056] The tape for label writer of the present invention is a tape for label writer in which (i) the tape for label writer has a layer structure composed of at least the process layer, substrate layer, ink layer, barrier layer, and adhesive layer in this order, (ii) the substrate layer is a synthetic resin film, and (iii) the ink layer contains one adhesive resin selected from the group including polyurethane-based resin, acryl-based resin and polyester-based resin, and a pigment.

[0057] The layer structure is a five-layered structure in which at least the process layer/substrate layer/ink layer/barrier layer/adhesive layer are laminated in this order from the outside to the inside (adherend side). The adhesive layer may be optionally provided between those layers. In addition, the separator layer is used to protect the adhesive layer if necessary, so that the layer structure is a six-layered structure of at least the process layer/substrate layer/ink layer/barrier layer/adhesive layer/separator layer. The adhesive layer may be optionally provided between those layers.

[0058] The tape is cut into a required width and length for a label writer to be used, and the cut tape is provided in a rolled state. The size of a cartridge varies depending on a cartridge-type label writer, which determines the width and length of the tape for label writer accordingly. FIG. 1 shows a five-layered structure of the process layer 1/substrate layer 2/ink layer 3/barrier layer 4/adhesive layer 5. FIG. 2 shows a six-layered structure of the process layer 1/substrate layer 2/ink layer 3/barrier layer 4/adhesive layer 5/separator layer 6.

EXAMPLES

[0059] Hereinafter, a specific description is made of the present invention with reference to Examples and Comparative Examples. The scope of the present invention is not limited by these Examples. Evaluation methods for the property of the tape for label writer of the present invention are as follows.

[Contamination on Adherend]

[0060] After a weather-resistant test by FADE METER (made by Suga Test Instrument Co., Ltd.), a residual ink and residual adhesive were evaluated by visual observation when the tape was peeled off from an adherend. The weather-resistant test was performed under a condition where the tape that was 12 mm in width×100 mm was attached to an aluminum plate (A1050P) and then irradiated with UV with the use of a UV carbon arc lamp in the FADE METER at an irradiance: 500 W/m.sup.2 (300 nm to 700 nm) at a BPT: 63° C. for 300 hours based on JISB7751 standard.

[0061] A: No ink or adhesive remains on the adherend when the label was peeled off.

[0062] C: An ink and adhesive remain on the adherend when the label was peeled off.

[Discoloration]

[0063] Discoloration in the ink layer of the tape after the above-mentioned weather-resistant test was evaluated by visual observation from the process layer.

[0064] A: No discoloration

[0065] B: Slightly discolored

[Printing Property]

[0066] The tape with 12 mm in width×1 m was set in a cartridge for TEPRA (registered trademark; made by King Jim Co., Ltd.), and a printing test was performed on a label writer (TEPRA (registered trademark; made by King Jim Co., Ltd.)) which uses a commercial ink ribbon system (heat transfer) to evaluate the printing property.

[0067] A: There is no printing blur, and the print is distinctly clear.

[0068] C: There is printing blur.

[Attaching Property to Curved Surfaces]

[0069] To an LAN cable (6 mm φ) made of polyvinyl chloride, the tape having a width of 12 mm was attached without being overlapped to each other, and the attaching property to curved surfaces was evaluated.

[0070] A: There is no lift of the tape after being attached, and the attaching property to curved surfaces is good.

[0071] B: The tape slightly lifts after being attached, but the attaching property to curved surfaces has no problem in use.

[Total Evaluation]

[0072] A: No ink or adhesive remains on the adherend when the label is peeled off. There is no discoloration. The print is also clear. The attaching property to curved surfaces is also good.

[0073] B: There is some discoloration of an ink.

[0074] C: An ink and adhesive remain on the adherend when the label is peeled off. There is printing blur.

Example 1

[0075] A process layer was prepared under a condition where an application liquid having polyester resin (VYLON (registered trademark) 200 made by Toyobo Co., Ltd.) dispersed into toluene and methyl ethyl ketone was applied by a coater to a polyester film (ESTER FILM made by Toyobo Co., Ltd.) of a substrate layer having a thickness of 19 μm, and then dried. The applied amount on the dried process layer is around 0.20 g/m.sup.2. In addition, an acrylic elastomer (product name: KURARITY LA2140e made by Kuraray Co., Ltd.) was used as acryl-based resin as adhesive resin on the back surface of the substrate layer such that the thickness would become 12 μm, and titanium oxide (rutile type, particle diameter of 0.3 μm to 0.4 μm) as a pigment was mixed such that the titanium concentration would become 47% by mass with respect to 100% by mass of a total amount of an ink layer, followed by coating in order to prepare the ink layer. Furthermore, a polyester film (PET LUMIRROR (registered trademark) #12) made by Toray Industries, Inc.) having a thickness of 12 μm was laminated as a barrier layer. In addition, a silicone-processed releasing paper having a thickness of 85 μm that would become a separator layer was coated with an acrylic adhesive (butyl acrylate/acrylic acid=95/5) so as to have a thickness of 18 μm as an adhesive layer, and the adhesive layer was laminated onto the above-mentioned barrier layer to yield the tape for label writer. Based on the above-mentioned evaluation method, the tape was peeled off from the adherend after the weather-resistant test. There was no contamination such as a residual ink or residual paste on the adherend, or discoloration in the ink layer. The printing property was also good. The evaluated result is shown in Table 1.

Example 2

[0076] The tape for label writer was prepared in the same way as Example 1, except that the acrylic elastomer as the adhesive resin for the ink layer was changed to an acrylic elastomer (product name: KURARITY LA2140e: LA1114=9:1 made by Kuraray Co., Ltd.) whose molecular weight was different from that of Example 1. Like Example 1, there was no contamination on the adherend due to peeling-off of the tape after the weather-resistant test, or discoloration. The printing property was also good. The evaluated result is shown in Table 1.

Example 3

[0077] The tape for label writer was prepared in the same way as Example 1, except that PET LUMIRROR #25 (thickness of 25 μm) made by Toray Industries, Inc. was used as the polyester film of the substrate layer, and the adhesive resin for the ink layer was changed to polyester-based resin (HI-BON (registered trademark) 7663: made by Hitachi Chemical Co., Ltd.). There was no contamination on the adherend due to peeling-off of the tape after the weather-resistant test, but discoloration was slightly found in the ink layer. The evaluated result is shown in Table 1.

Comparative Example 1

[0078] The tape for label writer was prepared in the same way as Example 1, except that PET LUMIRROR #38 (thickness of 38 μm) made by Toray Industries, Inc. was used as the polyester film of the substrate layer, the ink layer was provided in which a gravure ink (product name: LAMI-STAR (registered trademark) made by Toyo Ink Co., Ltd., BELLE COLOR (registered trademark) made by Sakata Inx Corporation, LAMIC (registered trademark) made by Dainichiseika Color & Chemicals Mfg. Co., Ltd.) having polyurethane-based resin as a binder was combined with an isocyanate hardener, and the barrier layer was not provided between the adhesive layer and the ink layer. There was a residual ink when the tape was peeled off from the adherend after the weather-resistant test. The evaluated result is shown in Table 1.

Comparative Example 2

[0079] The tape for label writer was prepared in the same way as Example 1, except that 1% of benzotriazole-based UV absorber (product name: TINUVIN (registered trademark) 326) was further added to the ink layer. Although a UV absorber was added to improve the weather-resistant, there was a residual ink, like Comparative Example 1. The evaluated result is shown in Table 1.

Comparative Example 3

[0080] The tape for label writer was prepared in the same way as Example 1, except that the substrate layer and the ink layer were changed with each other to place the ink layer on the uppermost surface. Placing the ink layer on the uppermost surface achieved a structure in which there was no interaction between the ink and the adhesive, but caused such an inconvenience as dissolution of the ink layer when the process layer was applied. In addition, the obtained tape for label writer exhibited printing blur in the test for printing property. The evaluated result is shown in Table 1.

TABLE-US-00001 TABLE 1 COMPARATIVE EXAMPLE 1 EXAMPLE 2 EXAMPLE 3 EXAMPLE 1 LAYER STRUCTURE PROCESS LAYER/ PROCESS LAYER/ PROCESS LAYER/ PROCESS LAYER/ SUBSTRATE LAYER/ SUBSTRATE LAYER/ SUBSTRATE LAYER/ SUBSTRATE LAYER/ INK LAYER/ INK LAYER/ INK LAYER/ INK LAYER/ BARRIER LAYER/ BARRIER LAYER/ BARRIER LAYER/ ADHESIVE LAYER/ ADHESIVE LAYER/ ADHESIVE LAYER/ ADHESIVE LAYER/ SEPARATOR LAYER SEPARATOR LAYER SEPARATOR LAYER SEPARATOR LAYER INK ADHESIVE ACRYLIC RESIN ACRYLIC RESIN POLYESTER RESIN POLYURETHANE LAYER RESIN RESIN PIGMENT TITANIUM OXIDE TITANIUM OXIDE TITANIUM OXIDE TITANIUM OXIDE UV UNAVAILABLE UNAVAILABLE UNAVAILABLE UNAVAILABLE ABSORBER BARRIER LAYER AVAILABLE AVAILABLE AVAILABLE UNAVAILABLE CONTAMINATION A A A C ON ADHEREND (RESIDUAL INK, RESIDUAL PASTE) DISCOLORATION A A B A PRINTING PROPERTY A A A A ATTACHING PROPERTY A A B A TO CURVED SURFACES TOTAL EVALUATION A A B C NO CONTAMINATION NO CONTAMINATION THERE IS SOME THERE IS ON ADHEREND, ON ADHEREND, DISCOLORATION RESIDUAL INK NO DISCOLORATION, NO DISCOLORATION, GOOD PRINTING GOOD PRINTING PROPERTY PROPERTY COMPARATIVE COMPARATIVE EXAMPLE 2 EXAMPLE 3 LAYER STRUCTURE PROCESS LAYER/ PROCESS LAYER/ SUBSTRATE LAYER/ INK LAYER/ INK LAYER/ SUBSTRAFE LAYER/ ADHESIVE LAYER/ ADHESIVE LAYER/ SEPARATOR LAYER SEPARATOR LAYER INK ADHESIVE POLYURETHANE POLYURETHANE LAYER RESIN RESIN RESIN PIGMENT TITANIUM OXIDE TITANIUM OXIDE UV AVAILABLE UNAVAILABLE ABSORBER BARRIER LAYER UNAVAILABLE UNAVAILABLE CONTAMINATION C A ON ADHEREND (RESIDUAL INK, RESIDUAL PASTE) DISCOLORATION A A PRINTING PROPERTY A C ATTACHING PROPERTY A A TO CURVED SURFACES TOTAL EVALUATION C C ALTHOUGH UV THERE IS PRINTING ABSORBER IS BLUR ADDED, THERE IS RESIDUAL INK

[0081] From the result in Table 1, it is confirmed that, in Examples 1 to 3 where the barrier layer is provided between the adhesive layer and the ink layer, even when the tape is peeled off from the adherend after the weather-resistant test, there is no residual ink or residual paste, while the barrier layer inhibits an adhesive from being transferred into the ink layer. In addition, in Examples 1 and 2 where an acrylic elastomer is used as the adhesive resin for the ink layer, there is no discoloration in the ink layer. On the other hand, in Example 3 where a polyester resin is used as the adhesive resin, discoloration is slightly caused in the ink layer. Furthermore, in Example 3, since the substrate layer is laminated on the barrier layer such that the substrate layer is thicker than those of Examples 1 and 2, the attaching property to curved surfaces is slightly reduced compared to Examples 1 and 2. This however causes no problem in use.

[0082] In contrast, because the barrier layer is not provided in Comparative Examples 1 and 2, there are a residual ink and residual paste. In Comparative Example 2, although a UV absorber is added to improve the weather-resistant, there are a residual ink and residual paste. In Comparative Example 3, the substrate layer and the ink layer are replaced each other for placing the ink layer on the uppermost surface. This could create a structure where there is no interaction between the ink layer and the adhesive layer, but degradation of the ink layer exhibited printing blur preventing the tape for label writer from achieving its function. In this regard, because Comparative Examples 1 to 3 do not have the barrier layer, there is no problem in laminating. Accordingly, there is no problem in the attaching property to curved surfaces.

INDUSTRIAL APPLICABILITY

[0083] According to the tape for label writer of the present invention, it is possible to inhibit the adhesive component from being transferred into the ink layer, to suppress anchoring fracture between the ink layer and the substrate layer, and further to prevent cohesive failure using specific adhesive resin for the ink layer. It is thus possible to provide a tape for label writer by which there is no residual ink or residual adhesive on an adherend when the label is peeled off from an adherend. There is also no discoloration in the ink layer. Based on the above, the industrial availability of the present invention is high.

REFERENCE SIGNS LIST

[0084] 1 process layer [0085] 2 substrate layer [0086] 3 ink layer [0087] 4 barrier layer [0088] 5 adhesive layer [0089] 6 separator layer