JP2004240282A - Thermosensitive adhesive label and method for manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the slipperiness of a contact boundary with a feed roller in a manufacturing line of a thermosensitive adhesive label to be wound and pasted around and to a drink-filled container and the like and the peelability of the label when discarding after the use of an article. <P>SOLUTION: The thermosensitive adhesive label is formed by covering the entire surface area of a thermosensitive adhesive layer (12) disposed on one profile of a label base material film (11) or the surface area exclusive of end edges which are the margins for bonding in winding or pasting of the label around or to the article with a masking layer (13) consisting of a continuous film or discontinuous films. The surface wetting tension ("JIS-K-6768") of the end edges which are the margins for bonding is adjusted to ≥38 mN/m. The masking layer (13) is formed as the continuous film (solid coating film) or the discontinuous films (grid-like, dot-pattern, etc.). The effects of forming the masking layer include the enhanced film conveyability in a label manufacturing process and the ease of label release for separating and recovering article bodies and labels in discarding of the used articles. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a heat-sensitive adhesive label which is wound and adhered to the surface of an article such as a beverage filling container and a method for producing the same.
[0002]
[Prior art]
The heat-sensitive adhesive label is attached to the target article by an adhesive action that is developed by heating a heat-sensitive adhesive layer provided on the back surface of the label. Since the heat-sensitive adhesive layer has no adhesive action until heated, unlike the pressure-sensitive adhesive label (adhesive label), there is no need to cover and protect the surface of the adhesive layer with release paper. In the step of adhering to the surface of the article, a complicated operation of peeling and removing the release paper (and an operation of recovering the release paper) is not required, and there is an advantage that the adhering operation can be made more efficient.
[0003]
The heat-sensitive adhesive label uses a long film as a label base material, forms a heat-sensitive adhesive layer on one side (the side that becomes the back side of the label), and prints on the other side (display of product information, decoration, etc.). For multicolor printing). The heat-sensitive adhesive layer is laminated (applied) over the entire surface of the label substrate by melt extrusion coating from the viewpoints of strength, adhesion stability, and the like.
A label of a predetermined size is cut out from the long heat-sensitive adhesive film manufactured as described above, and is adhered to a target article through a heating (expressing an adhesive action) treatment of the adhesive layer.
[0004]
[Problems to be solved by the invention]
The heat-sensitive adhesive label is difficult to maintain in a continuous manner in the continuous transfer operation of the film in the manufacturing process (particularly, the transfer operation in the label sticking process), and after using an article such as a bottle to which the sticker is attached. Conventionally, it has been a problem that it is difficult to separate the label for separating and collecting the article main body and the label at the time of disposal.
[0005]
Difficulties in the continuous transfer operation are due to poor sliding properties of the surface of the heat-sensitive adhesive layer. Insufficient slipperiness makes the rolling contact between the roll surface and the film unstable in the continuous transfer line, causing roll-up and breakage of the film in the line, making high-speed transfer operation difficult and severely limiting line efficiency. Become. As a countermeasure against this, it has been conventionally practiced to add a lubricant (for example, fatty acid amides) to the heat-sensitive adhesive layer so as to have a required slip property. However, in this case, when the film is rolled, the front surface of the film and the heat-sensitive adhesive layer overlap with each other, so that the lubricant easily adheres to the front surface of the film due to the bleeding of the lubricant in the heat-sensitive adhesive layer. If the lubricant adheres to the front surface of the film, the adhesion to the printing ink deteriorates, the quality of printing (display / decoration of product information, etc.) is impaired, and the amount of overlapping adhesive when attaching the label to the product Also has a problem that the adhesive strength of the label is weak and the label is easily turned up or peeled off during the distribution process.
[0006]
On the other hand, the difficulty in peeling the label when the main body and the label after using the article are separated and collected is due to the polarization treatment of the heat-sensitive adhesive layer. Polarization treatment (in which a polar group is introduced into the surface of the heat-sensitive adhesive layer) typified by corona discharge treatment increases the surface wetting tension (JIS-K6768) of the heat-sensitive adhesive layer and activates (adhesion action). This is an important treatment that has the effect of shortening the heating time required for the heat treatment, lowering the activation temperature, strengthening the adhesive action, etc., and making it possible to increase the speed and efficiency of the labeling operation and reduce the heat energy cost. is there. However, the enhancement of the adhesive force by the polarization treatment makes it difficult to peel off the label after use. Strengthening the adhesive strength of the label and facilitating peeling are opposite properties, but ensuring a stable state of label sticking during the distribution process (preventing label turnover / peeling) and facilitating separate collection after use In view of this, it is desired to satisfy the two conflicting characteristics at the same time.
[0007]
However, there is no example in which an effective solution to the above problem of the heat-sensitive adhesive label has been proposed. Therefore, the present invention eliminates the use of lubricants and the accompanying problems, enables high-speed and efficient heat-sensitive adhesive label production lines and sticking lines, and maintains the stability of label sticking to articles. An object of the present invention is to provide a heat-sensitive adhesive label and a method for manufacturing the same, which can ensure the ease of label peeling required when discarding a used article.
[0008]
[Means for Solving the Problems]
The present invention has a heat-sensitive adhesive layer on one side of the label substrate film, a heat-sensitive adhesive label that is wound and adhered to an article with both edges being an adhesive margin,
The entire surface area of the surface of the heat-sensitive adhesive layer or the surface area excluding the edge serving as the bonding margin is covered with a masking layer made of a continuous film or a discontinuous film, and the surface wetting tension of the edge serving as the bonding margin ( "JIS-K6768", hereinafter the same) is characterized by being 38 mN / m or more.
[0009]
The method for producing a heat-sensitive adhesive label according to the present invention includes, for a heat-sensitive adhesive layer formed on one side of a label substrate, a masking layer on the entire surface area or a surface area excluding an edge serving as the adhesion allowance. The method is characterized in that it has a masking step for forming, or has a masking step and a polarization treatment step for activating the heat-sensitive adhesive layer.
[0010]
In the heat-sensitive adhesive label of the present invention, as a shielding effect of the masking layer covering the heat-sensitive adhesive layer, the slipperiness with the film feed roller in the heat-sensitive adhesive label production line is improved. For this reason, it is possible to omit the addition of the lubricant to the heat-sensitive adhesive layer or to reduce the amount of the lubricant, and the problems associated with the use of the lubricant (transfer of the lubricant to the front surface of the film and the accompanying decrease in printability / Insufficient label adhesion) can be avoided. In addition, as an effect of the masking layer covering the heat-sensitive adhesive layer, the adhesive strength after heating is suppressed to a low level, and the difficulty of label peeling (separation of the label from the article itself) when disposing of the article is reduced, Separation and collection of the article body and the label are facilitated.
[0011]
The strength of the shielding effect of the masking layer is arbitrarily controlled by the coating composition (film thickness, coating density, etc.) of the masking layer and the type of masking agent, as described later. Even when coated with a layer, the adhesive strength required for label attachment can be ensured. Thus, by appropriately designing the coating composition of the masking layer, two contradictory characteristics of stability of label attachment to the article surface and facilitation of label peeling required for sorting and collecting after use of the article are simultaneously satisfied.
[0012]
In the heat-sensitive adhesive label of the present invention, the surface wetting tension of the heat-sensitive adhesive layer (covered with the masking layer or omitted from the masking layer) at the edge serving as an adhesion margin at the time of sticking the label is 38 mN / m. The reason stated above is to ensure the stability of label attachment to the article.
[0013]
As another measure to address the above-mentioned problems related to the heat-sensitive adhesive label, such as slipperiness, blocking, and label peeling after use, the application of the heat-sensitive adhesive layer was changed to partial application instead of full application. However, it is difficult to selectively apply partially by melt extrusion coating. Partial application is possible if a solution type heat-sensitive adhesive is used.However, since drying after application is required, the process is complicated, and there is a restriction that thick coating is difficult. It is difficult to meet various demands such as stability of the product, slipperiness in a label manufacturing process and a sticking process, and ease of peeling after use of an article. On the other hand, according to the present invention, the surface wetting tension and the adhesive strength of the heat-sensitive adhesive layer by the melt extrusion coating can be finely adjusted by the masking surface area and the coating composition, and the above-mentioned various properties desired for the heat-sensitive adhesive label Can be satisfied at the same time.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be specifically described with reference to the drawings showing examples.
FIG. 1 [a] [b] and FIG. 2 [a] [b] show examples of the heat-sensitive adhesive label of the present invention (in each figure, [a]: cross-sectional view in the longitudinal direction of the film, [b]). Figure: Plan view on the back side of the film). The heat-sensitive adhesive film (10) includes a label base film (11), a heat-sensitive adhesive layer (12) formed on one side (label back side) of the base film (11), and the heat-sensitive adhesive. A masking layer (13) laminated on the layer (12), and a print layer (print layer for displaying and decorating product information) formed on the front side of the base film (11). (14) and the like.
[0015]
The label (1) is repeatedly formed in the longitudinal direction of the heat-sensitive adhesive film (10). The labels (1) are sequentially cut one by one from the heat-sensitive adhesive film (10) in a label sticking line and are stuck to a target article (described later). Edge (1E) of label (1) ₁ ) And (1E) ₂ ) Is a portion serving as a lap-adhesion allowance when the label (1) is wound and adhered to the target article (3) (the figure shows an example of a beverage-filled bottle) as shown in FIG.
[0016]
The masking layer (13) that covers the heat-sensitive adhesive layer (12) is formed by printing, using a known printing method such as letterpress printing, gravure printing, flexo printing, screen printing, or the like. Film) or a discontinuous film, for example, a grid pattern such as a grid (a square grid or a rectangular grid) or an oblique grid, a slit striped pattern, a halftone plate, a halftone plate, or a halftone dot pattern. If necessary, an application pattern using a combination of a continuous film and a discontinuous film is employed. 3 to 5 are examples of a coating pattern of a masking layer formed of a discontinuous film. FIG. 3 schematically shows an example of a lattice pattern, FIG. 4 shows a stripe pattern, and FIG. 5 schematically shows an example of a halftone dot pattern. .
[0017]
The shielding effect of the masking layer (13) can be controlled by the coating structure of the masking layer. When the masking layer (13) is formed as a continuous film, the heat-sensitive adhesive is formed on the front side through the film thickness (or through fine cracks in the film) by making the film relatively thin. A suppressed adhesion of the layer (12) can be produced, and the thicker the film, the stronger the shielding effect. On the other hand, in the masking layer (13) formed as a discontinuous film, a suppressed adhesive force of the heat-sensitive adhesive layer (12) may be generated on the front surface side through a minute gap of the coating film. it can. The effect of the heat-sensitive adhesive layer (12) on the front side is adjusted by the density of the coating film. For example, in the case of a grid pattern (FIG. 3), a grid pattern and a line width are large and small. In a striped pattern (FIG. 4), a slit pattern and a line width are large and in a halftone pattern (FIG. 5). In the coating film pattern, each is adjusted by the halftone dot density (area ratio) based on the screen ruling, gradation, and the like.
[0018]
Next, the covering pattern by the masking layer will be described.
The heat-sensitive adhesive film (10) of FIG. 1 is connected to the edge (1E) of the label (1). ₁ Since the masking layer (13) is formed except for the part which becomes the bonding margin), the edge (1E) ₁ ) (The heat-sensitive adhesive layer 12 is exposed) has a sufficient surface wetting tension (about 38 mN / m or more) and a desired heating as an adhesion allowance due to the intrinsic physical properties of the heat-sensitive adhesive layer (13). High later bonding strength (about 4 N / 15 mm or more) is ensured.
Edge (1E ₁ ) Is a continuous film or a discontinuous film (a lattice pattern, a stripe pattern, a halftone dot pattern, etc.). The stability of label attachment to the article is determined by the edge (1E ₁ ) Can be secured only by the adhesive action of ₁ -13 ₂ -13 ₁ ) Is not required, the surface area (13) ₁ -13 ₂ -13 ₁ The masking layer (13)) can be formed as a continuous film having a large film thickness so that the adhesive force can be sufficiently suppressed and the slipperiness can be further improved.
[0019]
In the label (1) having the covering pattern shown in FIG. 1, depending on the form and material (metal, glass, plastic, etc.) of the target article, the edge (1E) ₁ In the case where it is difficult to secure the stability of the attached state to the article only by the adhesive action of () (problems such as idling or misalignment of the label on the article surface are likely to occur), as a countermeasure, for example,
{Circle around (1)} Covering area of masking layer (13) (area "13" shown in FIG. ₁ -13 ₂ -13 ₁ )), For example, the area (13) ₁ ) To omit the masking layer (expose the heat-sensitive adhesive layer 12) to increase the area of adhesion to the article surface;
{Circle around (2)} When the masking layer (13) is a continuous film having a large thickness, its surface area (the area “13” shown in FIG. ₁ -13 ₂ -13 ₁ ") Or a part thereof (for example, the surface area 13). ₁ ) To reduce the film thickness or replace the continuous film with a discontinuous film having a relatively low coating density (such as a lattice pattern, a stripe pattern, a halftone dot pattern, etc.) to cause a suppressed adhesive action.
And other treatments are appropriately performed. These coating film adjustments are appropriately performed in consideration of the balance between the slipperiness required for the label manufacturing process and the ease of label peeling after use of the article.
[0020]
The heat-sensitive adhesive film (10) of FIG. 2 is different from FIG. 1 in that the entire surface of the heat-sensitive adhesive layer (12) [the edge (1E ₁ )], A coating pattern in which a masking layer (13) is formed on the entire surface. The masking layer (13) is formed as a continuous film (solid coating) or a discontinuous film (lattice pattern, stripe pattern, halftone dot pattern, etc.). Edge (1E ₁ In the case of (3), the thickness (in the case of a continuous film) or the coating density (in the case of a discontinuous film) of the masking layer (13) is adjusted so as to obtain a sufficient adhesive force for sticking a label. m or more.
[0021]
In the label (1) of FIG. 2, the edge (1E ₁ ) Alone can ensure the stability of label attachment to the article, and the other area (13) ₄ ) Is not required, the surface area (13) ₄ By forming the masking layer of (1) as a continuous film having a large thickness (solid coating) or a discontinuous film having a high coating density (concentration), the slipperiness in the label manufacturing process and the label peelability at the time of article disposal can be improved. Can be further enhanced.
[0022]
On the other hand, the edge (1E ₁ In the case where it is difficult to secure the stability of the attached state only by the adhesive action of () (the label is likely to rotate or shift on the surface of the article),
(1) If the masking layer (13) is a continuous film having a large thickness, its surface area (13) ₄ ) (For example, the surface area 13 shown in FIG. ₃ ), Or replace the continuous film with a discontinuous film (grid pattern, stripe pattern, halftone pattern, etc.)
(2) If the masking layer (13) is a discontinuous film, its surface area (13 ₄ ) (For example, the surface area 13 shown in FIG. ₃ ) Is replaced by a discontinuous film having a lower coating density (concentration),
The area (13 ₄ It is preferable to increase the adhesive force to the article by the adhesive action of ()). Such coating adjustment is appropriately performed in consideration of the balance between the slipperiness required in the label manufacturing process and the ease of label peeling after use of the article.
[0023]
As described above, the shielding effect of the masking layer (13) can be adjusted by the coating film structure (such as the thickness of a continuous film or the density of a coating film of a discontinuous film). The design differs depending on the type of the heat-sensitive adhesive layer (12) and the masking layer (13), and the surface area where the masking layer is to be formed (the edge area or other surface area that becomes the bonding allowance of the label) and the target. The required shielding effect varies depending on the material type of the article (for example, metal can, glass bottle, PET bottle, etc.). Therefore, in concrete implementation, it is necessary to make appropriate adjustments in consideration of these specific conditions.
[0024]
As a specific example, a heat-sensitive adhesive layer (12) having a layer thickness of 15 μm is formed by melt-extrusion coating of a resin containing ethylene-ethyl acrylate copolymer as a main component, which is a label wound and adhered to a metal can. Then, an example in which a masking layer (13) made of an ultraviolet-curable varnish is formed thereon is as follows.
(1) The masking layer (13) formed as a continuous film has a thickness of about 0.1 to 10 μm, and within this range, an edge portion (1E) serving as an adhesion allowance. ₁ ) And the thickness of other surface areas are adjusted.
(2) The masking layer (13) of the discontinuous film formed as a lattice pattern (FIG. 3) and a stripe pattern (FIG. 4) has a line interval (center-to-center distance between adjacent lines) of about 0.3 to 3.0. 0 mm and a line width (line thickness) of about 0.3 to 3.0 mm. Within this range, the edge portion (1E ₁ ) And the line spacing and line width in the other area are adjusted.
(3) The masking layer (13) of the discontinuous film formed as a halftone dot pattern (FIG. 5) has a halftone dot concentration (area ratio) of about 20 to 60%. Edge (1E ₁ ) And the density of the other surface areas are adjusted.
[0025]
Next, the laminated constituent material of the heat-sensitive adhesive label of the present invention will be described.
The base film (11) is a polyethylene film having a thickness of about 10 to 100 μm, a polyolefin resin film such as a polypropylene film, a polyester resin such as polyethylene terephthalate, a resin film such as a polystyrene resin, or a synthetic film composed of these resins. Paper etc. In addition, a polystyrene-based foamed resin sheet, a polyolefin-based foamed resin sheet, and the like, which are relatively thick (about 80 to 500 μm in thickness) and have heat insulating properties, cushioning properties, and the like can be given. As these various films, synthetic papers, foamed resin sheets and the like, those having heat shrinkability can also be used.
[0026]
The heat-sensitive adhesive layer (12) is formed by a melt extrusion coating method or the like. Examples of the heat-sensitive adhesive include an ethylene-vinyl acetate copolymer, an ethylene-acrylic acid copolymer, an ethylene-methacrylic acid copolymer, and an ethylene-acrylate copolymer (ethylene-ethyl acrylate, ethylene-acrylic acid 2). -Ethylhexyl), ethylene-methacrylic acid ester copolymer (such as ethylene-ethyl methacrylate) and the like, and various known agents can be used. The layer thickness is, for example, 5 to 30 µm.
[0027]
The masking layer (13) covering the heat-sensitive adhesive layer (12) has a non-adhesive surface, is less likely to be softened by heating, and has a slippery property, as compared with the heat-sensitive adhesive. Various varnishes and printing inks can be used as the film agent. In particular, UV-curable ink and UV-curable varnish are effective. The masking layer can be either transparent or opaque. Film formation on the surface of the heat-sensitive adhesive layer (12) can be performed by applying various known printing techniques as described above.
The printing ink layer (14) is formed by various known printing methods by applying various inks used for printing of this kind of label (display of product information and decorative printing).
[0028]
Next, the manufacturing process and the sticking process of the heat-sensitive adhesive label of the present invention will be described.
The manufacturing process of the heat-sensitive adhesive label of the present invention includes a masking step of forming a masking layer (13) on the surface of the heat-sensitive adhesive layer (12) formed on one side of the base film, or It differs from the conventional manufacturing process in that it has a polarization treatment (activation of the heat-sensitive adhesive layer).
FIG. 6 shows an example of a manufacturing process including a masking step and a polarization processing step. In this manufacturing process, other processes (a, b) except "b process: polarization treatment (activation of heat-sensitive adhesive layer)" and "d process: formation of masking layer (coating of heat-sensitive adhesive layer)" c, e, f) do not differ from the conventional production process of heat-sensitive adhesive labels.
[0029]
The base film (the front surface of the film on which display and decorative printing is performed has been subjected to a polarization treatment such as corona discharge treatment for improving the familiarity with the printing ink) is fed out from the roll, A heat-sensitive adhesive layer (12) is formed on one side (back side) by melt-extrusion coating (step a) and wound up on a roll. The wound film roll is set on a feeding portion of a printing machine provided with a polarization processing device (such as a corona discharge processing device), and the heat-sensitive adhesive layer (12) is subjected to a polarization process while being fed from the film roll. After the (b step), display / decorative printing on the front surface of the base film (c step) and masking of the heat-sensitive adhesive layer (d step) are performed. The order of the display / decorative printing (step c) and the masking step (step d) may be reversed. Next, an ultraviolet irradiation treatment (step e) for curing the printing ink layer and the masking layer (when the printing ink and the masking agent are ultraviolet curable inks) is performed, and the film is wound around a roll. Further, the film roll is supplied to a slit line, slit into a predetermined label width size (step f), and wound. The wound film roll is supplied to a label sticking line (described later).
[0030]
In the above manufacturing process, masking (d step) is performed after the polarization treatment (b step). This step has an advantage that the adhesiveness of the masking layer (13) to the heat-sensitive adhesive layer (12) is good. Even if the order of these two steps is reversed, if the required adhesion of the masking layer (13) is ensured, a line configuration in which the polarization treatment is performed after the masking layer is formed can be adopted (this step is adopted). In this case, the surface of the masking layer is subjected to a polarization treatment, but the masking layer can be implemented because blocking and the like are less likely to occur than the heat-sensitive adhesive layer). Even in this case, it is sufficient that the surface wetting tension of the portion serving as the bonding margin is adjusted to 38 mN / m or more. In the case where the surface wetting tension of the heat-sensitive adhesive layer (12) becomes insufficient due to long-term storage or the like after the production of the heat-sensitive adhesive film, it is only necessary to carry out an additional polarization treatment in the label sticking line. If the polarization process in the above step is omitted, the polarization process may be performed on the label sticking line.
[0031]
FIG. 7 shows an example of a label sticking line. The label sticking line includes a polarization treatment device (for example, a corona discharge treatment device) (21), a label cutting unit (22), a label holding drum (23), and a heat activation device (24) for a heat-sensitive adhesive layer. And an article supply / discharge device (26) (27).
The heat-sensitive adhesive film (10) is wound on a winding roll (10). _R ) Is continuously supplied via a feed roller (R). Since the heat-sensitive adhesive film (10) of the present invention has been subjected to the polarization treatment of the heat-sensitive adhesive layer during the manufacturing process, it is directly transferred to the cutting unit (22) without passing through the polarization treatment device (21). can do. When the polarization processing is required, the transfer path may be switched to pass through the polarization processing device (21).
[0032]
The heat-sensitive adhesive film (10) sent to the cutting unit (22) is supplied to the rotary cutter (22). ₁ ) And holding rollers (22) ₂ ), Are sequentially cut into individual labels (1), and are suction-held on the peripheral surface of a label holding drum (23), and the heating device (24) (hot air heater, infrared heater, near heater) is rotated by rotation of the drum (23). After passing through an infrared heater or the like, it is heated to a predetermined temperature (for example, 60 to 150 ° C.).
In conjunction with the supply operation of the label (1), the belt conveyor (26) of the article transport device (26) ₁ ) And screw shaft (26 ₂ ) Is supplied by a star wheel (26). ₃ ) To the label holding drum (23) at the sticking position, and the holding drum (23) and the guide plate (26). ₄ ), While rolling and passing therethrough, the label (1) is wound and adhered to the body surface of the article (3). The article to which the label has been attached is sent to the belt conveyor (27) of the discharging device (27). ₁ ) And presser belt (27 ₂ ) To pass while rolling, thereby completing the winding and sticking of the label (1).
[0033]
Unlike the heat-sensitive adhesive film of the present invention, no polarization treatment is performed in the manufacturing process of the conventional heat-sensitive adhesive film (having no masking layer). This is because, when a polarization treatment is performed in the manufacturing process, blocking tends to occur on the winding surface of the roll (in some cases, it is necessary to discard one roll). Therefore, when a conventional heat-sensitive adhesive film is used, a polarization treatment in a label sticking line is indispensable to obtain sufficient adhesive strength with good heating efficiency. On the other hand, when the heat-sensitive adhesive film of the present invention has been subjected to a polarization treatment in the manufacturing process, the polarization treatment can be omitted, and the label sticking operation can be speeded up and made more efficient. Can be.
[0034]
【Example】
Using a biaxially stretched polypropylene film as a base film, a heat-sensitive adhesive containing ethylene ethyl acrylate as a main component, and an ultraviolet curable ink (varnish) as a masking agent, the process shown in FIG. The process may be omitted) to produce a test label. Then, it is supplied to the label sticking line of FIG. 7 and wound and stuck on the surface of a beverage metal can (made of steel).
[0035]
[Example 1]
A masking layer is formed on the heat-sensitive adhesive layer as a continuous film (film thickness 2 μm), and a test label (edge 1E serving as an adhesion margin) having the specifications shown in FIG. ₁ Is omitted). Note that the polarization processing in the step b (FIG. 6) is omitted.
In the label sticking line, after the surface wetting tension of the heat-sensitive adhesive layer at the bonding margin (edge) is set to 45 mN / m by corona discharge treatment, the heat-sensitive adhesive layer is activated by heating to 120 ° C. Wound and stuck.
The slipperiness of the label in the label sticking line was good.
The adhesive force of the edge portion (overlapping portion) of the label stuck to the metal can was as good as 5.0 N / 15 mm or more. Further, the adhesive strength of the portion covered with the masking layer to the surface of the metal can was very low and could be easily peeled off.
[0036]
[Example 2]
After subjecting the heat-sensitive adhesive layer to a corona discharge treatment, a masking layer (same as in Example 1) is formed, and a test label having the specifications shown in FIG. ₁ (The masking layer has been omitted). The surface wetting tension of the heat-sensitive adhesive layer at the adhesion margin (edge) of this label was 40 mN / m.
In the label sticking line, the heat-sensitive adhesive layer was heated and activated (heating temperature: 120 ° C.) without being subjected to the polarization treatment, and was wound and stuck on a metal can.
The slipperiness of the label in the label sticking line was good.
The adhesive strength of the edge portion (overlapping portion) of the attached label was as good as 4.6 N / 15 mm. Peeling from the surface of the metal can was easily performed in the same manner as in Example 1.
[0037]
[Example 3]
The masking layer was printed on a gradation plate (halftone density = 20% of the area of the bonding allowance, 60% of the area other than the bonding allowance), and the test label (the edge 1E serving as the bonding allowance) having the specifications of FIG. ₁ (A masking layer is also formed on the heat-sensitive adhesive layer of Example 1). However, the polarization processing in step b (FIG. 6) was omitted.
In the label sticking line, a corona discharge treatment was performed in the same manner as in Example 1 to adjust the surface wetting tension of the heat-sensitive adhesive layer at the bonding margin (edge) to 45 mN / m. It was activated by heating to 120 ° C. and attached to a metal can.
The slipperiness of the label on the sticking line was good.
The adhesive strength of the edge portion (overlapping portion) of the attached label was as good as 4.1 N / 15 mm. Peeling from the surface of the metal can was also easily performed.
[0038]
As described above, the heat-sensitive adhesive label of the present invention has good slipperiness with respect to a feed roller, and can obtain a stable state of adhering to an article by a good adhesive force of an adhesion margin, and can be attached to an article and a label. Is easy to separate at the time of separation.
[0039]
【The invention's effect】
The heat-sensitive adhesive label of the present invention has an improved effect of forming a masking layer on the heat-sensitive adhesive layer, in which the slipperiness of the film with respect to the film feed roller is improved, and the stability of film transfer in the label manufacturing process and the label sticking line is enhanced. As a result, it is possible to omit or reduce the addition of a lubricant to the heat-sensitive adhesive layer, and it is possible to omit problems associated with the addition of the lubricant, for example, transfer of the lubricant to the winding surface of a film roll (reduction in printability of the surface of the base film). , Causing deterioration in the adhesive strength required for attaching the label to the article).
In addition, the heat-sensitive adhesive label of the present invention has the effect of forming a masking layer covering the heat-sensitive adhesive layer, which alleviates the difficulty of label peeling for separating the article main body and the label upon disposal after use of the article. In addition, it is easy to separate and collect articles and labels.
Furthermore, in the heat-sensitive adhesive label of the present invention, as a forming effect of the masking layer, the occurrence of blocking (adhesion phenomenon of the wound surface between the heat-sensitive adhesive layer and the base film) is reduced and alleviated. For this reason, a polarization process is performed in the label manufacturing process (the film roll is wound up in the final stage), so that it is possible to simplify the equipment configuration of the label sticking line, increase the efficiency of the label sticking operation, and the like. .
[Brief description of the drawings]
FIG. 1 is a view showing an example of a coating pattern of a heat-sensitive adhesive layer by a masking layer in a heat-sensitive adhesive label of the present invention ([a]: sectional view in the longitudinal direction of the film, [b]: plan view).
FIG. 2 is a diagram ([a]: a cross-sectional view in the longitudinal direction of the film, [b]: a plan view) showing another example of a coating pattern of the heat-sensitive adhesive layer by the masking layer in the heat-sensitive adhesive label of the present invention. is there.
FIG. 3 is an explanatory plan view showing an example of a coating structure of a masking layer in the heat-sensitive adhesive label of the present invention.
FIG. 4 is an explanatory plan view showing another example of the coating structure of the masking layer in the heat-sensitive adhesive label of the present invention.
FIG. 5 is an explanatory plan view showing another example of the coating structure of the masking layer in the heat-sensitive adhesive label of the present invention.
FIG. 6 is an explanatory view of a production process of the heat-sensitive adhesive label of the present invention.
FIG. 7 is an explanatory front view showing an example of a device configuration of a line for attaching a heat-sensitive adhesive label.
FIG. 8 is a perspective view showing an example of a mode of attaching a heat-sensitive adhesive label to an article.
[Explanation of symbols]
1: heat-sensitive adhesive label
1E _1, 1E ₂ : Label edge (adhesion allowance)
3: Goods (bottle)
10: heat-sensitive adhesive film
10 _R ： Film take-up roll
11: base film 12: heat-sensitive adhesive layer
13: Masking layer 14: Printing ink layer
R: Film feed roller
21: Polarization processing device
22: Cut unit
22 ₁ ： Rotating cutter 22 ₂ : Holding roller
23: Label holding drum
24: heating device
26: Article supply device
26 ₁ :belt conveyor
26 ₂ : Screw shaft 26 ₃ : Star wheel
27: Article discharge device
27 ₁ ： Belt conveyor 27 ₁ : Presser belt

Claims (3)

A heat-sensitive adhesive label that has a heat-sensitive adhesive layer on one side of the label base film and is wound and adhered to an article with both edges being an adhesive margin,
The entire surface area of the surface of the heat-sensitive adhesive layer or the surface area excluding the edge serving as the bonding margin is covered with a masking layer made of a continuous film or a discontinuous film, and the surface wetting tension of the edge serving as the bonding margin ( JIS-K6768) is a heat-sensitive adhesive label characterized by being 38 mN / m or more. A heat-sensitive adhesive layer is formed on one side of a label base material, and a continuous film or a discontinuous film is masked on the entire surface area of the surface of the heat-sensitive adhesive layer or a surface area excluding an edge serving as the adhesion allowance. The method for producing a heat-sensitive adhesive label according to claim 1, wherein the layers are formed by lamination. After forming the heat-sensitive adhesive layer on one side of the label substrate, a polarizing treatment step for activating the surface of the heat-sensitive adhesive layer and a heat-sensitive adhesive layer to be performed before or after the polarizing treatment step It has a masking step, in the masking step, forming a masking layer consisting of a continuous film or a discontinuous film covering the entire surface area of the heat-sensitive adhesive layer or the surface area excluding the edge serving as the bonding margin. The method for producing a heat-sensitive adhesive label according to claim 1.

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