JP4538733B2 - Method for evaluating processability of adhesive sheet and method for producing adhesive label - Google Patents

Description

  The present invention relates to a method for evaluating the processability of a pressure-sensitive adhesive sheet laminated in the order of a substrate, a pressure-sensitive adhesive, and a release sheet, and a method for producing a pressure-sensitive adhesive label incorporating this processability evaluation method in a process.

  The pressure-sensitive adhesive sheet is used after being processed into a label, a sticker or the like in a wide range from commercial use to household use. An adhesive label is produced from this adhesive sheet, and this adhesive label is affixed to a product to be adhered and its container.

In the process, first, printing according to the purpose is performed on the surface of the base material of the pressure-sensitive adhesive sheet, and then, for example, a die cutting blade is inserted and cut to a layer composed of the base material and the pressure-sensitive adhesive, so-called “half-cut”. A label is punched into a desired shape (hereinafter referred to as “punching”).
Next, after unnecessary parts (the base material layer and the pressure-sensitive adhesive layer which are not printed on the base material and become a waste part) generated by the punching are peeled off (hereinafter referred to as “scrap removal”), once. This adhesive sheet is rewound into a roll.
And using the automatic sticking machine (auto labeler), the adhesive label remaining on the wound adhesive sheet is peeled off from the release sheet and attached to the adherend.

  Therefore, in the processing stage of the pressure-sensitive adhesive label, (1) the punching ability when punching the label, (2) the scraping ability when removing the residue, and (3) ) Three workability of auto labeler suitability is required. Here, these three processability are collectively referred to as process suitability.

Conventionally, a test method of JIS-Z0237 is known as a method for evaluating the physical properties of this pressure-sensitive adhesive sheet.
However, with this test method alone, it has been difficult to properly determine whether the pressure-sensitive adhesive sheet has good processability.

  Therefore, at the actual label manufacturing site, the prototype adhesive sheet is put into the above-mentioned adhesive label production line, processed, and the prototype label is attached to the adherend to determine whether the processing suitability is good or bad. It was.

  However, in the above-mentioned method for evaluating the processing suitability by putting a prototype sheet into an actual adhesive label production line, it is necessary to stop and test the operating line, and (1) it takes time and effort. (2) In addition, there was a problem that the loss of the sample for evaluation was large, and (3) it was difficult to evaluate and manage lot fluctuation of the adhesive sheet material in advance.

  In addition, as a method for evaluating the degree of stringing of the adhesive, the stress value measured at 400% to 600% strain in the stress-strain curve of the adhesive may be caused by punching and / or punching of the label. There is known a method for evaluating the difficulty of stringing an adhesive when a necessary part is peeled off (see Patent Document 1). However, since the disclosed method is an evaluation with a pressure-sensitive adhesive alone, the state of the completed “pressure-sensitive adhesive sheet” was not evaluated. Therefore, it was difficult to grasp the lot blur between the same products, and it was difficult to compare the actual adhesive sheet where the trouble occurred and the actual adhesive sheet where the trouble did not occur. Moreover, when evaluating the completed “adhesive sheet”, it takes time and effort to scrape off the adhesive.

  Furthermore, in this document, the sticky sheet is punched into a 45 mm x 45 mm square shape with a stick printing machine, and then the scrap is raised. In the process, it is described that the moment when the necessary part and the part other than the necessary part are peeled off are filmed to evaluate the threading length of the adhesive, and the case where the threading length of the adhesive is less than 0.5 mm. It is said. However, in this method, since it is set and evaluated in an actual printing processing machine, it is necessary to prepare a roll sample, and it is not premised on performing evaluation with a small amount of sample. Moreover, although the evaluation standard of “◎” is within 0.5 mm of the stringing length, in reality, there are cases where the punching processability of the label is poor even when the stringing length is within 0.5 mm. Occurrence of so-called “label rising” in which the label is lifted together with the residue part is caused by the re-adhesion between the adhesive surfaces that have been cut once after the label is punched out until the residue is removed. In the determination based on the evaluation criteria of ◎ within the stringing length of 0.5 mm, it was difficult to appropriately determine the re-adhesion between the adhesives, and more detailed evaluation criteria were required.

JP 2003-286458 A (Claims, 29th paragraph)

  In view of the above-mentioned problems of the prior art, the present invention is a process for pressure-sensitive adhesive sheets that can determine the processing suitability of a pressure-sensitive adhesive sheet with a small amount of sample without actually performing a processing test of the pressure-sensitive adhesive sheet on the pressure-sensitive adhesive label production line. The purpose is to provide a method for evaluating aptitude. Above all, during scrap removal work, an evaluation method that can grasp in advance how easily the trouble that the label surface is contaminated by sticking the thread and the so-called “label rise” where the label is lifted together with the waste part. The purpose is to provide.

  Moreover, this invention aims at providing the manufacturing method of the adhesive label which incorporated the evaluation method of the workability of this adhesive sheet in the process.

To solve this problem,
The present invention is a method for evaluating the processing suitability of a pressure-sensitive adhesive sheet laminated in the order of a substrate, a pressure-sensitive adhesive, and a release sheet,
Arbitrary locations of the laminate composed of the base material and the pressure-sensitive adhesive laminated on the release sheet,
By cutting into the laminate from a direction substantially perpendicular to the substrate surface,
Partially cutting the laminate on the release sheet, or bisecting the laminate on the release sheet,
Then, the one laminate that was partially cut or bisected is peeled from the release sheet,
Due to the size of the threading area of the pressure-sensitive adhesive in the cross-section peeled part of the peeled laminate,
The present invention provides a processability evaluation method for pressure-sensitive adhesive sheets, characterized by evaluating processability.

  The present invention also includes a first step for producing a pressure-sensitive adhesive sheet laminated in the order of a base material, a pressure-sensitive adhesive, and a release sheet, a second step for printing on the base material of the pressure-sensitive adhesive sheet, and a pressure-sensitive adhesive subjected to this printing. A third step of punching out the pressure-sensitive adhesive label from the sheet, a fourth step of removing the base material layer and the pressure-sensitive adhesive layer of the residue from the release sheet from the pressure-sensitive adhesive sheet after punching out the pressure-sensitive adhesive label, and the pressure-sensitive adhesive after removing the waste The sheet of the pressure-sensitive adhesive sheet according to claim 1, further comprising a fifth step of winding the sheet into a roll, and during or after any one of the first to fifth steps. The present invention provides a method for producing a pressure-sensitive adhesive label for performing a processability evaluation method.

According to the method for evaluating the processability of the pressure-sensitive adhesive sheet of the present invention, it is possible to appropriately determine the processability of the pressure-sensitive adhesive sheet without actually performing a process test of the pressure-sensitive adhesive sheet on the pressure-sensitive adhesive label production line. From the time when the label is punched to the time when the scrap removal operation is performed, the pressure-sensitive adhesives that should have been punched and broken contact each other and come into close contact with each other. The processability evaluation method of the present invention is characterized in that the cut surfaces of the half-cut base material layer and the pressure-sensitive adhesive layer are peeled off, so that the pressure-sensitive adhesives that can occur between the punching of the label and the removal of the residue The re-adhesiveness can be appropriately reproduced, and it is possible to easily determine the troubles caused by the stringing of the adhesive during the scrap removal operation and the ease of raising the label.
In particular, the method for evaluating the processability of the pressure-sensitive adhesive sheet according to the present invention determines the punchability of the label based on the “area” of the stringed portion, not just based on the stringed “length” as described in the prior art. Therefore, it is possible to appropriately determine the degree of re-adhesion between the pressure-sensitive adhesives at the punched and broken portions, and it is possible to predict whether or not the label will rise due to re-adhesion. For example, when the following phenomenon occurs, it is impossible to determine whether the label is likely to rise when the determination based only on the string “length” is performed.
(1) When a large number of stringing occurs even when the stringing length is short (when the stringing area is large)
In this case, the label rises easily due to a large number of strings.
(2) Even if the threading length is long, the number of threading is small (when the threading area is small)
In this case, the number of the stringing is small, so that the label rise hardly occurs.
Therefore, it is more appropriate to judge by “area” as in the evaluation method of the present invention.

  Further, according to the method for evaluating the processability of the pressure-sensitive adhesive sheet of the present invention, it is possible to reduce the time required for the evaluation of processability without taking time and to reduce the amount of sample necessary for the evaluation of processability from the conventional method. It is possible to reduce and reduce the lot fluctuation of the adhesive sheet material in advance.

  Furthermore, according to the method for evaluating the processability of the pressure-sensitive adhesive sheet of the present invention, a pressure-sensitive adhesive sheet material having good processability can be easily selected.

  And according to the manufacturing method of the adhesive label of this invention, the adhesive label can be manufactured by incorporating this evaluation method of the processability of an adhesive sheet into an adhesive label manufacturing process appropriately.

  The method for evaluating the workability of the pressure-sensitive adhesive sheet according to the present invention includes the step of laminating an arbitrary portion of a laminate composed of a base material and a pressure-sensitive adhesive layered on a release sheet from a direction substantially perpendicular to the base material surface. By cutting into the body, partially cutting the laminate on the release sheet, or bisecting the laminate on the release sheet, and then partially cutting or bisecting The laminate is peeled from the release sheet, and the processability is evaluated based on the size of the threaded area of the pressure-sensitive adhesive in the cross-section peeled portion of the peeled laminate. In addition, in this specification, the arbitrary place of the above-mentioned “laminated body composed of the base material and the adhesive layer laminated on the release sheet is arranged in a direction substantially perpendicular to the base material surface with respect to the laminated body. “Cutting” means that the laminate on the release sheet is partially cut or the laminate on the release sheet is bisected.

This pressure-sensitive adhesive sheet has a structure in which a substrate, a pressure-sensitive adhesive, and a release sheet are laminated in this order. Examples of the substrate include a film, a nonwoven fabric, and paper. Specifically, the material of the film includes polypropylene, polyethylene, polyester, polystyrene, polyvinyl chloride, nylon, cellophane and the like. Moreover, as a material of a nonwoven fabric, pulp, rayon, Manila hemp, acrylonitrile, nylon, polyester, etc. are mentioned. Examples of paper include high-quality paper and resin-coated paper.
Corona treatment or an anchor coating agent may be applied to the surface of the base material surface on which the adhesive is laminated.

Examples of the pressure-sensitive adhesive include rubber-based, acrylic-based, silicone-based, urethane-based, and vinyl ether-based types of polymers. In addition, as the form of the pressure-sensitive adhesive, a solvent system, an emulsion-type pressure-sensitive adhesive, a water-based pressure-sensitive adhesive, or the like, a hot-melt pressure-sensitive adhesive, a UV curable pressure-sensitive adhesive, an EB-curable pressure-sensitive adhesive, or the like should be used. Can do.
The thickness of the pressure-sensitive adhesive is preferably 5 to 200 μm, more preferably 10 to 50 μm, in terms of the thickness after drying.

  As release sheet, glassine paper, kraft paper, clay coated paper, paper laminated with polyolefin film such as polyethylene, paper coated with resin such as polyvinyl alcohol and acrylate copolymer, polyolefin synthetic such as polyester and polypropylene Examples include a resin film or the like coated with a release resin such as a fluororesin or a silicone resin.

  This pressure-sensitive adhesive sheet can be produced, for example, by applying a pressure-sensitive adhesive to a release sheet, performing a treatment such as drying, heat curing, ionizing radiation curing, etc., and bonding a substrate thereto. On the contrary, it can also be obtained by a method in which a pressure-sensitive adhesive is applied to a substrate, subjected to treatment such as drying, thermosetting, ionizing radiation curing, and a release sheet is bonded thereto. Moreover, in order to improve the adhesiveness of a base material layer and an adhesive layer, you may bond together under high temperature.

In order to evaluate the processability of the pressure-sensitive adhesive sheet, the pressure-sensitive adhesive sheet is half-cut, and then the laminate composed of one base material layer and the pressure-sensitive adhesive layer partially or cut into two by half-cutting is peeled off. The peeled portion of the cross section of the peeled laminate is observed with an optical microscope, visual observation, or the like, and the peeling process of the adhesive between the surface of the substrate that is not peeled off and the laminate to be peeled is observed.
This peeling may be performed immediately at room temperature after half-cutting the pressure-sensitive adhesive sheet, but it is preferably performed after leaving for 1 minute to 3 hours after half-cutting. Furthermore, it is preferably performed after leaving at a temperature of 30 to 50 ° C. for 30 minutes to 3 hours, and more preferably left for 1 hour in a temperature atmosphere at 40 ° C. When peeling is performed after being left in the atmosphere in the above temperature range for the above time, the flow of the pressure-sensitive adhesive proceeds, and the adhesiveness between the cut pressure-sensitive adhesives increases, or the pressure-sensitive adhesive on the surface of the substrate and the release sheet As the adhesion of the material increases, it becomes a condition for accelerated testing, the difference in stringing can be clearly observed, and the difference that is difficult to find by just observing inline with a seal printing machine Can do.

  FIG. 1 is a perspective view schematically showing a state where one laminated body cut into two by half-cut is peeled. FIG. 1 is a diagram showing a state in which adhesion between adhesives occurs at the interface between the adhesive 7 and the adhesive 2 and stringing of the adhesive 5 occurs. FIG. 2 is a side view schematically showing a cross-section peeling portion of the pressure-sensitive adhesive sheet in the peeling process. In this peeling process, an angle θ between one base material 6 and the adhesive 7 half-cut from the adhesive sheet 1 and the other base material 2 and the adhesive 7 half-cut is preferably 3 to 45 degrees. Is peeled off at a distance L of 0.1 to 1.5 mm, preferably 0.2 to 0.4 mm, and most preferably 0.3 mm until it becomes 10 to 30 degrees, most preferably 15 degrees. The peeling speed is 5 to 1000 mm / min, preferably 50 to 500 mm / min, and most preferably 300 mm / min.

  At this time, when the adhesives hardly adhere to each other at the interface between the adhesive 7 and the adhesive 2, which is a half-cut cross-sectional portion, the stringing of the adhesive 5 hardly occurs. Furthermore, when peeling occurs at the interface between the pressure-sensitive adhesive 7 and the release sheet 4, the phenomenon of adhesive residue on the release sheet 4 does not occur. If it peels quickly from the surface, stringing of the adhesive 5 hardly occurs. FIG. 3 is a side view of a cross-section peeled portion of the pressure-sensitive adhesive sheet 1 where stringing hardly occurs. In this pressure-sensitive adhesive sheet 1, it is difficult for the pressure-sensitive adhesives to come into close contact with each other at the time of label processing, and since the label can be easily peeled off from the release sheet 4, good processability can be achieved.

  However, when the peeling does not proceed promptly with the peeling of the base material 6 and the pressure-sensitive adhesive 7, or when the peeling occurs in the bulk of the pressure-sensitive adhesive 5 and causes cohesive failure, large stringing is observed. FIG. 4 is a side view of a cross-section peeled portion of the pressure-sensitive adhesive sheet 1 in which large stringing has occurred. In this pressure-sensitive adhesive sheet 1, re-adhesion between the pressure-sensitive adhesives at the punched cross-section of the label easily occurs during label processing, and the label cannot be easily peeled off from the release sheet 4, so that good processability cannot be achieved.

In the present invention, whether the adhesive label is suitable for processing is determined based on the size of the threading area 3 of the adhesive shown in FIG. The stringing area 3 is calculated by the following method.
(1) In the peeling step shown in FIG. 2, let R be the contact between one half-cut adhesive 7 and the other half-cut base material 2.
(2) Let P be the point of the threading portion of the adhesive 5 that is the furthest portion from the contact point R and is in contact with the adhesive 7.
(3) Similarly, let Q be the point where the adhesive 5 is the furthest part farthest from the contact R and is in contact with the substrate 2.
(4) The stringing area 3 is an area of a triangle PQR that connects the point P, the point Q, and the point R with a straight line.

Therefore, the stringing area 3 means a size including the part of the adhesive 5 in the triangle PQR and the part of the space where the adhesive 5 does not exist. When the size of the threading area 3 of this adhesive is small, it is preferably within 0.06 mm ² , and particularly preferably within 0.04 mm ² . The processability is good. Further, even if the stringing area calculated by the above method is not less than the above numerical range, if the area of the space portion where the adhesive 5 is not present is 90% or more of the area of the triangle PQR, the stringing is performed. The area is preferably considered to be within the above range.

  As a matter of course, even when the size of the threading area 3 of the pressure-sensitive adhesive is within the above range, the pressure-sensitive adhesive 5 causes cohesive failure and remains on the surface of the release sheet 4. Needless to say, when the film is completely peeled from 6 and moved onto the release sheet 4, the processability of the pressure-sensitive adhesive label is poor.

  This method for evaluating the processability of the pressure-sensitive adhesive sheet may be carried out alone, or may be incorporated into one step of the method for producing a pressure-sensitive adhesive label.

  The manufacturing method of the pressure-sensitive adhesive label is the first step of manufacturing a pressure-sensitive adhesive sheet laminated in the order of the base material, the pressure-sensitive adhesive, and the release sheet, the second step of printing on the base material of the pressure-sensitive adhesive sheet, and the printing. A third step of punching out the pressure-sensitive adhesive label from the pressure-sensitive adhesive sheet, a fourth step of removing the base material layer and the pressure-sensitive adhesive layer of the residue from the release sheet from the pressure-sensitive adhesive sheet after punching out the pressure-sensitive adhesive label, and a pressure-sensitive adhesive after removing the waste And a fifth step of winding the sheet into a roll. The process for evaluating the processability of the pressure-sensitive adhesive sheet of the present invention can be performed during any of the first to fifth steps or after the fifth step.

  By using the pressure-sensitive adhesive sheet evaluated as good by using this method for evaluating the processability of the pressure-sensitive adhesive sheet, line troubles in the method for producing a pressure-sensitive adhesive label can be avoided in advance.

  Hereinafter, the present invention will be described in more detail by way of examples. The present invention is not limited to the following examples.

[Example 1]
<Creation of adhesive sheet>
A release sheet (OKB-105NC, manufactured by Oji Paper Co., Ltd.) is coated with an adhesive (SPS-1260, manufactured by Dainippon Ink & Chemicals, Inc.) whose main component is an acrylic copolymer so that the thickness after drying is 20 μm. And then dried for 3 minutes at 90 ° C. using a hot air dryer, bonded with a 50 μm polyethylene terephthalate (PET) film (Ester A-4100, manufactured by Toyobo Co., Ltd.), and aged for 7 days at 40 ° C. It was created.

<Evaluation test for processability of adhesive sheet>
The pressure-sensitive adhesive sheet was cut into a size of width 10 mm × length 100 mm, then half-cut with a die-cut blade in the length direction, and the release sheet surface was fixed to a holder. Subsequently, the one base material layer and the pressure-sensitive adhesive layer cut into two by half-cutting were peeled off at a speed of 300 mm / min.

  In FIG. 2, the angle θ between the surface of the base material that is not peeled off and the pressure-sensitive adhesive layer on which the base material layer that is peeled off is 15 degrees, and the base material layer that is peeled off from the surface of the base material that is not peeled off When the distance L to the pressure-sensitive adhesive layer laminated with 0.3 became 0.3 mm, peeling was stopped, and the cross-section peeled portion was observed with an optical microscope (KH-2700, manufactured by Hilox). The magnification of the optical microscope was 250 times. As shown in FIG. 2, let R be the contact between one half-cut adhesive 7 and the other half-cut base material 2. The point that is the farthest part that is in contact with the adhesive 7 is P, the point that is the farthest part from the contact point R and that is in contact with the base material 2 is Q, the point P, the point Q, The threading area of the adhesive represented by the triangle PQR connecting the point R with a straight line was measured.

The stringing area of this pressure-sensitive adhesive sheet was 0.018 mm ^{2 as} shown in FIG. This value corresponds to the size of the threading area 3 of the pressure-sensitive adhesive within 0.06 mm ^2, which is a standard for judging whether or not the processability of the pressure-sensitive adhesive label is good.

<Evaluation of processability of actual adhesive label production line>
This pressure-sensitive adhesive sheet was put into an actual pressure-sensitive adhesive label production line, and the pressure-sensitive adhesive label was punched out, the residue was removed from the punched-out pressure-sensitive adhesive sheet, and the pressure-sensitive adhesive sheet was wound up after removal. Next, this winding sheet was put into an automatic sticking machine, and an adhesive label was stuck on the adherend container.

  This pressure-sensitive adhesive sheet had good punching suitability and residue picking suitability in the pressure-sensitive adhesive label processing step. Furthermore, the auto labeler suitability was also good in the adhesive labeling process. In particular, during the scrap removal operation, the stringing phenomenon of the pressure-sensitive adhesive was practically negligible, and the label was not raised.

[Example 2]
The pressure-sensitive adhesive sheet was the same as in Example 1 except that SK Dyne 701F-L (manufactured by Soken Chemical Co., Ltd.) was used as the pressure-sensitive adhesive and that the aging period at the time of preparation of the pressure-sensitive adhesive sheet was 1 day at 23 ° C. It was created. Evaluation of the processability of this pressure-sensitive adhesive sheet was performed in the same manner as in Example 1.
The stringing area of this pressure-sensitive adhesive sheet was 0.16 mm ^{2 as} shown in FIG. This value exceeds the size 0.06 mm ² of the threading area 3 of the pressure-sensitive adhesive, which is a criterion for judging whether or not the processability of the pressure-sensitive adhesive label is good.

Moreover, it carried out similarly to Example 1, and evaluated the punching aptitude of the adhesive sheet, the scrap removal aptitude, and the auto labeler aptitude of the adhesive label.
The punching suitability and scrap removal suitability of this pressure-sensitive adhesive sheet were poor. Furthermore, the auto labeler suitability was poor in the adhesive labeling process. In particular, stringing of the adhesive during the scrap removal operation was noticeable, and the label surface was conspicuously contaminated. In addition, the occurrence of label rise was conspicuous.

  From the above results, it was found that the pressure-sensitive adhesive sheet having a small stringing area has good processability even in the production of an actual pressure-sensitive adhesive label by the method for evaluating the processability of the pressure-sensitive adhesive sheet.

  Therefore, it was confirmed that if the method for evaluating the processability of the pressure-sensitive adhesive sheet of the present invention is used, the processability of the pressure-sensitive adhesive sheet can be appropriately determined without actually performing a process test of the pressure-sensitive adhesive sheet on the pressure-sensitive adhesive label production line.

It is the perspective view which represented typically the cross-section peeling part of the adhesive sheet in a peeling process. It is the side view which represented typically the cross-section peeling part of the adhesive sheet in a peeling process. It is a side photograph of the cross-section peeling part of the adhesive sheet with favorable processability. It is a side view photograph of a section exfoliation part of a pressure sensitive adhesive sheet with poor workability.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Adhesive sheet 2 Base material 3 Stringing area 4 Release sheet 5 Adhesive 6 Base material 7 Adhesive

Claims (3)

It is a method for evaluating the processing suitability of a pressure-sensitive adhesive sheet laminated in the order of a substrate, a pressure-sensitive adhesive, and a release sheet,
Arbitrary locations of the laminate composed of the base material and the pressure-sensitive adhesive laminated on the release sheet,
By cutting into the laminate from a direction substantially perpendicular to the substrate surface,
Partially cutting the laminate on the release sheet, or bisecting the laminate on the release sheet,
Then, the one laminate that was partially cut or bisected is peeled from the release sheet,
Due to the size of the threading area of the pressure-sensitive adhesive in the cross-section peeled part of the peeled laminate,
A method for evaluating the processability of an adhesive sheet, characterized by evaluating processability. Until one of the laminates from the pressure-sensitive adhesive sheet is 3 to 45 degrees between the substrate and the one laminate,
The method for evaluating the processability of the pressure-sensitive adhesive sheet according to claim 1, wherein the adhesive sheet is peeled by 0.1 to 1.5 mm at a peeling speed of 5 to 1000 mm / min. A first step of producing a pressure-sensitive adhesive sheet laminated in the order of a substrate, a pressure-sensitive adhesive, and a release sheet;
A second step of printing on the substrate of the adhesive sheet;
A third step of punching out an adhesive label from the printed adhesive sheet;
A fourth step of removing the base material layer and the pressure-sensitive adhesive layer of the residue from the release sheet from the pressure-sensitive adhesive sheet after punching the pressure-sensitive adhesive label;
A fifth step of winding the adhesive sheet after scrap removal into a roll,
During any of the first to fifth steps or after the fifth step,
The manufacturing method of the adhesive label which performs the evaluation method of the workability of the adhesive sheet of Claim 1 or 2.

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