JP2002114950A - Self-adhesive sheet - Google Patents

Abstract

(57) [Problem] An object of the present invention is to provide a pressure-sensitive adhesive sheet using a polyolefin-based film as a substrate, which does not easily curl regardless of a change in ambient temperature. SOLUTION: An adhesive layer is provided on a base film formed from a polyolefin-based resin composition, and a separator is laminated on the adhesive layer in a releasable manner. Dimensional change rate difference L [L = |
La−Lb | (La: dimensional change rate of separator, L
b: dimensional change rate of the base film)] is 0.15 or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a pressure-sensitive adhesive sheet provided with a pressure-sensitive adhesive and a separator such as release paper.

[0002]

2. Description of the Related Art Heretofore, as an adhesive sheet used for various labels and stickers, there is known an adhesive sheet in which an adhesive is provided on a base film, and a separator such as release paper is attached to one surface of the adhesive. As the substrate film, a film using a PVC substrate film is widely used. However, due to recent environmental problems, non-P
With the promotion of VC, there is a tendency that the base film is changed from PVC to another material. As an alternative material, a polyolefin-based film is mainly used.

On the other hand, as a separator, laminated paper obtained by laminating a polyolefin resin such as polyethylene on both sides or one side of pulp paper, glassine paper, clay-coated paper, paper base, etc., is coated with a release agent such as silicon or fluorine on both sides. Alternatively, one coated on one side is generally used.

[0004] The pressure-sensitive adhesive sheet comprising the polyolefin-based substrate film and the separator as described above has a problem that the shape changes largely with the change of the ambient temperature, that is, the curl greatly occurs in summer or winter. Specifically, polyolefin has a larger dimensional change when the ambient temperature changes than paper, and therefore, in the summer (at high temperatures)
In the case of (1), the curl is performed with the substrate film on the outside, and in winter (at a low temperature), the curl is performed with the separator on the outside.

When the sheet is curled as described above, the sheet is caught by a machine and cannot be printed at the time of feeding when printing the adhesive sheet, or when the adhesive sheet is attached to an adherend (such as various containers) by an automatic labeler. Misalignment occurs.

[0006] As means for making such a curl phenomenon difficult to occur, there are. Make the temperature at the time of product use equal to that at the time of product manufacture By using a polyolefin resin film to which an inorganic fine powder is added as a substrate, the dimensional change rate of the substrate film (polyolefin) is reduced. There are measures such as using a high-strength separator, but there are the following problems.

[0007]

Since the above-mentioned means depends on the method of use, it is impossible to disseminate it to all users such as end customers. Further, in the above-described means, even if the dimensional change rate can be reduced materially,
The base film must be manufactured without stretching (if the film is stretched at the time of manufacture, the film will remain stressed and cause curl). Suitable thickness for labels and stickers (0.04 to 0.25 mm It is difficult to obtain a thin film, and there is a possibility that the dimensional change of the release paper may cause trouble. In addition, the above-described means deteriorates post-processability (winding, printing, cutting, pasting, and the like).

[0008] In view of the above, an object of the present invention is to provide a pressure-sensitive adhesive sheet using a polyolefin-based film as a base material, which does not easily curl regardless of a change in ambient temperature.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in view of the above-mentioned problems, and as a result, the main cause of the curl phenomenon of the pressure-sensitive adhesive sheet is that the separator and the base film at the time of increase or decrease of the ambient temperature are reduced. Focusing on the fact that the degree of expansion or contraction is significantly different, it has been found that the above-mentioned problems can be solved by the following means. That is, the present invention
A pressure-sensitive adhesive layer is provided on a base film formed from the polyolefin-based resin composition, and a separator is laminated on the pressure-sensitive adhesive layer in a releasable manner. The dimensional change in an atmosphere at a temperature of 0 to 60 ° C. Rate difference L [L = | La-Lb |
(La: dimensional change rate of the separator, Lb: dimensional change rate of the base material film)] is 0.15 or less.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a pressure-sensitive adhesive sheet 1 according to the present invention is provided with a pressure-sensitive adhesive layer 3 coated with a pressure-sensitive adhesive on one surface 2a of a base film 2 made of a polypropylene resin film. And on one surface 3a of the pressure-sensitive adhesive layer 3,
It has a configuration in which a peelable separator 5 is provided.

The absolute value of the difference between the dimensional change rate Lb of the base film 2 and the dimensional change rate La of the separator 5 at an ambient temperature of 0 to 60.degree. Various types can be used as long as they are not more than .15.

Specifically, the base film 2 is formed by forming a polypropylene resin composition into a film, and examples thereof include polyolefin resins such as polypropylene, polyethylene, and ethylene-propylene copolymer. Usually, a single-layer structure is used, but a multi-layer structure of two or more layers may be used.

On the other hand, as the separator 5, various kinds of paper such as paper and synthetic paper, resins such as a synthetic resin film, and a laminate of paper and resin can be used. However, since the separator 5 needs to have the same thermal characteristics as the base film 2, it is preferable that the separator 5 be composed of the same type of polyolefin resin composition as the base film because it is more suitable.

In consideration of a post-treatment step such as adhesive processing and primer processing, the separator 5 is preferably made of a material having heat resistance such as an adhesive or a primer that does not deform when dried.

The thickness of the base film 2 is not particularly limited. However, considering the use of labels, stickers, etc., if it is too thin, it is difficult to stick it on the other hand. Considering the fact that the body floats without following the body, it is preferably about 0.04 to 0.25 mm. Similarly, the thickness of the separator 5 is not particularly limited, but if it is too thick, the pressure-sensitive adhesive sheet 1
Cannot be rolled up and printed smoothly. On the other hand, if it is too thin, it tends to be thermally deformed during drying.
About 0.20 mm is preferable.

The pressure-sensitive adhesive is not particularly limited, and any known pressure-sensitive adhesive can be used. For example, butyl rubber, isobutylene rubber and a mixture thereof are dissolved in an organic solvent such as toluene, xylene, MEK and hexane. Pressure-sensitive adhesives such as rubber-based adhesives, acrylic adhesives in which a copolymer of 2ethylhexyl acrylate and n-butyl acrylate, methyl acrylate, methyl methacrylate, etc. are dissolved in an organic solvent, and hot melt An adhesive or the like can be used. The thickness of the adhesive layer 3 is, for example, 50 to 150 μm after drying with a rubber-based adhesive.
m, set to about 10 to 50 μm after drying with an acrylic pressure-sensitive adhesive.

Various additives such as a stabilizer, an ultraviolet absorber, a flame retardant, and an antistatic agent can be blended in the base film 2 and the separator 5.

The base film 2 of the present invention is prepared, for example, by heating and melting a crystalline polypropylene resin to a predetermined temperature, extruding it from an extruder through a T-type die, and solidifying it by cooling. This sheet is stretched by a predetermined factor in the vertical and / or horizontal directions while being heated to a predetermined temperature, and then heat-set, whereby a film-shaped base film 2 can be obtained. Further, the substrate film 2 may be subjected to various surface treatments such as corona treatment and overcoating. In addition, when the separator 5 is formed from a synthetic resin film, it can be obtained by the same procedure. Then, an adhesive is applied to the separator 5 and the base film 2
The adhesive sheet 1 can be produced by sticking to the adhesive sheet.

The pressure-sensitive adhesive sheet 1 according to the present invention has a temperature of 0.degree.
The absolute value of the difference between the dimensional change of the base film 2 and the dimensional change of the separator 5 at 0.1 ° C. is set to 0.15 or less. It is difficult to curl. In addition, base film 2
Since (and the separator 5) are made of a polyolefin-based resin, they have little adverse effect on the environment after disposal.

[0020]

The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these examples. Example 1 Preparation of Base Film 100 parts by weight of a polypropylene resin (J-Aromamer PM620A, manufactured by Nippon Polyolefin Co., Ltd.), 0.2 part by weight of an antioxidant (Sumilyzer GA80, manufactured by Sumitomo Chemical Co., Ltd.) and a lubricant (steer) 0.2 parts by weight of (calcium phosphate) were mixed, and the obtained resin composition was kneaded and melted at a temperature of 150 to 180 ° C., and the kneaded material was supplied to a four inverted L-shaped 24 inch calender and roll temperature was 160 ~ 190 ° C
(Refers to all rolls that form four inverted L-shaped rolls,
Not all rolls were at the same temperature and each roll was within this roll temperature range).
The film was stretched to a thickness of 00 μm to obtain a film. Further, the surface of the film was subjected to a corona discharge treatment in order to increase the adhesiveness with the adhesive.

Preparation of pressure-sensitive adhesive sheet A polypropylene-based multilayer film (R
S02, manufactured by Sun Tox Co., Ltd., having a thickness of 60 μm and surface-treated with a silicone-based release agent), and drying the release-treated surface with a pressure-sensitive adhesive (SK Dyne 131) to a thickness of 30 μm.
Acrylic pressure-sensitive adhesive manufactured by Soken Chemical Co., Ltd.) to form a pressure-sensitive adhesive layer, which was then dried and adhered to the above-mentioned base film under a 23 ° C. atmosphere to obtain a pressure-sensitive adhesive sheet according to Example 1. I got

Example 2 A polypropylene-based multilayer film (R) was used as a separator.
S02 A pressure-sensitive adhesive sheet according to Example 2 was obtained in the same manner as in Example 1, except that Sun Tox Co., Ltd., 80 μm thickness, surface treatment with a silicone release agent) was used.

Example 3 Polypropylene resin (PF540 as base film)
B, manufactured by Nippon Polyolefin Co., Ltd.), to obtain a pressure-sensitive adhesive sheet according to Example 3 in the same manner as in Example 1.

COMPARATIVE EXAMPLE 1 Synthetic paper (SL-110C, manufactured by Kite Chemical Industry Co., Ltd., total thickness 145 μm, surface treated with a silicone release agent) obtained by coating high quality paper of 78 g / m ² with 17 μm of polyethylene as a separator. A pressure-sensitive adhesive sheet according to Comparative Example 1 was obtained in the same manner as in Example 1 except that the pressure-sensitive adhesive sheet was used.

Comparative Example 2 A polypropylene resin (PF540) was used as the base film.
B, manufactured by Nippon Polyolefin Co., Ltd.) as a separator using a polyethylene terephthalate film (PET75).
× 1C, manufactured by Nippa Co., Ltd., thickness 75 μm, surface treatment with a silicon-based release agent) was used in the same manner as in Example 1 to obtain a pressure-sensitive adhesive sheet according to Comparative Example 2.

Comparative Example 3 An adhesive sheet according to Comparative Example 3 was obtained in the same manner as in Example 1 except that a polyethylene resin (GX600, manufactured by Chisso Corporation) was used as the base film.

Comparative Example 4 A synthetic paper (SL) in which a polyethylene resin (GX600, manufactured by Chisso Corporation) was coated as a base film, and a high quality paper of 78 g / m ² was coated with 17 μm of polyethylene as a separator.
-110C, manufactured by Kite Chemical Industry Co., Ltd., total thickness 145μ
m, surface treatment with a silicone release agent)
In the same manner as in Example 1, an adhesive sheet according to Comparative Example 4 was obtained.

Measurement of dimensional change rate Before preparing each pressure-sensitive adhesive sheet, the base films and separators used in Examples 1 to 3 and Comparative Examples 1 to 4 were measured at 0 ° C, 23 ° C, 40 ° C, and 60 ° C. When the dimensional change rates La and Lb in the respective atmospheres were measured,
As shown in Tables 1 and 2. The dimensional change rate (%) was measured by attaching a 50-cm-long mark line to the obtained base film in an atmosphere at 23 ° C.
The length after standing for 60 minutes in each atmosphere of 0 ° C. and 60 ° C. was measured, and the formula was calculated as follows: (length after leaving / original length) × 100
It calculated according to. In addition, the minus sign in Tables 1 and 2 indicates a case where the marked lines (dimensions) of both La and Lb are reduced.

[0029]

[Table 1]

[0030]

[Table 2]

Test Examples Each of the pressure-sensitive adhesive sheets obtained in Examples 1 to 3 and Comparative Examples 1 to 4 was cut into 15 cm squares, and was cut at a predetermined ambient temperature (0 ° C., 23 ° C., 40 ° C., 60 ° C.). After leaving for a while, as shown in FIG. 2, it was placed on a flat table 6, and the height H of the warped end was measured. As shown in FIG. 2, a curl with the substrate film 2 inside is indicated by minus (-), and a curl with the separator 5 inside is shown by plus (+), though not shown. Table 3 shows the results. Table 3 also shows the dimensional change rate difference L = | La−Lb |. Each result is shown as an average value for five test pieces.

[0032]

[Table 3]

In Examples 1 to 3, the warp height was in the range of ± 15 mm in all the temperature ranges of 0 to 60 ° C., and it was confirmed that the curl phenomenon was small. On the other hand, in Comparative Examples 1 to 4, the warpage height was extremely high in some temperature range of 0 to 60 ° C.

[0034]

According to the pressure-sensitive adhesive sheet according to the present invention, the temperature is generally 0 to 60 when stored, transported, and used.
Under the atmosphere of ° C., regardless of the change of the ambient temperature, there is an effect that the curl phenomenon hardly occurs.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an adhesive sheet.

FIG. 2 is a reference diagram for measuring the warpage height of the pressure-sensitive adhesive sheet.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Adhesive sheet, 2 ... Base film, 3 ... Adhesive layer, 5
…separator

Claims (1)

[Claims] An adhesive layer is provided on a base film formed from a polyolefin-based resin composition, and a separator is laminated on the adhesive layer in a releasable manner. In the following dimensional change rate difference L,
A pressure-sensitive adhesive sheet, wherein the pressure-sensitive adhesive sheet is configured to be 0.15 or less. Dimensional change rate difference L = | La-Lb | (La: dimensional change rate of separator, Lb: dimensional change rate of base film).