JPH05287242A - Pressure-sensitive adhesive sheet - Google Patents

Abstract

PURPOSE:To obtain the subject sheet markedly reduced in curling due to moisture or the heat from a printer by forming a combination of a surface base layer with a pressure-sensitive adhesive layer and a releasable support layer, wherein the base layer and the support layer are made of plastic films and have specified thermal shrinkage characteristics. CONSTITUTION:This sheet is one comprising a surface base layer (A), a pressure-sensitive layer (B) and a releasable support layer (C). The layers A and B are each made of a plastic film, and both films have thermal shrinkage characteristics satisfying formulas I and II under conditions of 175 deg.CX2min (wherein HS (A) is the average value (%) of the heat shrinkages of the film for the surface base layer in one direction and the rectangular direction under conditions of 175 deg.CX2min, and HS (C) is the average value (%) of the thermal shrinkages of the film for the releasable support layer in one direction and the rectangular direction under conditions of 175 deg.CX2min.

Description

Detailed Description of the Invention

[0001]

The present invention relates to an adhesive label (for example,
The present invention relates to a pressure-sensitive adhesive sheet which is useful as an adhesive label such as a process management label and a shelf management label) and which can be applied to a toner fixing type printing such as a laser beam printer.

[0002]

2. Description of the Related Art Conventionally, pressure-sensitive adhesive labels have been prepared by using a pressure-sensitive adhesive to attach a surface-based paper to a support made of release paper that has been treated with a release agent such as silicone or polyethylene. It is used by laminating, printing, printing, half-cutting, punching, etc. on a surface base paper, peeling it appropriately, and laminating it on a target object.

However, when the surface base material is paper, it is difficult to apply it to applications requiring strength such as water resistance and abrasion resistance.

Attempts have been made to use a water-resistant plastic film as the surface substrate, but when the releasable support is made of paper, the paper undergoes dimensional change due to moisture absorption or moisture release, After the surface base material and the releasable support are adhered to each other, a dimensional difference occurs between the surface base material and the film which is the releasable support during standing, and the phenomenon that the sheet curls on one side occurs. It is difficult to put into practical use in the process. In addition, winding at the time of adhesive processing tends to cause curling. In order to eliminate the dimensional difference as much as possible, some measures have been taken such as giving water to the paper at the time of adhesive processing, but the sufficient effect has not been obtained.

Therefore, it has been attempted to use a plastic film having low water absorption as the releasable support so that the dimensional change due to moisture is small.

However, particularly in recent years, when trying to adopt bar code labels for management such as product management in large-scale stores such as supermarkets and parts management in automobile factories, the management is accompanied by computerization and speeding up. As for barcode printing, the adoption of toner fixing type printing such as electrophotographic type and laser beam type is increasing.

In these toner heat fixing methods, the temperature of the fixing roll is extremely high (about 180 to 100) due to the structure of the printer.
Since the temperature of the adhesive label is 200 ° C.), a conventional adhesive label using a plastic film as a surface substrate causes a great amount of thermal curl after printing on a printer, is very difficult to handle, and cannot be put to practical use.

An object of the present invention is to provide a pressure-sensitive adhesive sheet (particularly a pressure-sensitive adhesive sheet for pressure-sensitive adhesive labels) that is extremely curled by neither moisture nor heat of a printer.

[0009]

DISCLOSURE OF THE INVENTION As a result of intensive studies for solving the above problems, the present inventors have found that the present invention can achieve the above object. That is, the present invention is a pressure-sensitive adhesive sheet comprising a surface base material layer (A), a pressure-sensitive adhesive layer (B) and a releasable support layer (C), wherein both the (A) layer and the (C) layer are plastic. The heat shrinkage characteristics of the (A) layer film and the (C) layer film at 175 ° C. × 2 minutes satisfy both of the following expressions (I) and (II). Adhesive sheet.

[0010]

[Equation 2]

[However, HS (A): average value (%) of heat shrinkage in one direction of the film for the surface base material layer in the direction of 175 ° C. × 2 minutes and in the direction perpendicular thereto, and HS (C): 1
It is the average value (%) of the heat shrinkage rate in one direction of the film for a releasable support layer and in the direction perpendicular thereto at 75 ° C. for 2 minutes. ]

In the present invention, the pressure-sensitive adhesive sheet has a structure in which a pressure-sensitive adhesive layer and a surface base material layer are laminated on a releasable support layer. The plastic film used for the surface base material layer (A) is not particularly limited as long as it is a film having properties that can satisfy both the formula (I) and the formula (II).
Examples thereof include polyolefins, polyesters, polyamides, polyimides, polysulfones, etc., preferably biaxially oriented polyester films, and more preferably white polyester films having cavities inside. Further, it is particularly preferable practically to provide a coat layer (binder resin, matting agent, etc.) as a toner receiving layer at the time of printing on the surface (printing side) of the film.

The thickness of the above film is usually 10 to 100.
μm, and preferably 25 to 75 μm. Also,
The thickness of the coat layer as the toner receiving layer is usually 0.1 to
It is 10 μm, and preferably 0.2 to 5 μm.

If desired, an organic or inorganic additive may be added to the above-mentioned film layer and coat layer.
There is no problem as long as the expressions (I) and (II) are satisfied. In particular, it is often preferable to add an antistatic agent or the like.

The plastic film used for the releasable support layer (C) is not particularly limited as long as it is a film having properties satisfying both formulas (I) and (II). For example, polyolefin, polyester, Polyamide, polyimide, polysulfone and the like can be mentioned, preferably a biaxially oriented polyester film, and more preferably a semitransparent polyester film having a cavity inside. A mold releasable support is obtained by subjecting the above plastic film to a mold release treatment with a silicone resin, a polyethylene resin or the like. The releasable support may be either a transparent type or a colored type, but a translucent matte tone is preferable. The matting is performed by a method of coating a resin containing inorganic particles or the like, a method of sand matting or a chemical matting, a kneading method (a method of adding inorganic particles such as silica), or the like.

The thickness of the releasable support is usually 20 to 25.
It is 0 μm, preferably 50 to 100 μm. When a mat coat layer is provided, its position is preferably on the side opposite to the release surface of the releasable support, and the thickness of the layer is usually 0.1 to 15 μm, preferably 0.2 to 5 μm. is there.

Examples of the pressure-sensitive adhesive include solvent-based or water-based pressure-sensitive adhesives that are commonly used, such as natural rubber-based, synthetic rubber-based, and acrylic-based pressure-sensitive adhesives. The thickness of the pressure-sensitive adhesive layer is usually 2 to 20 μm, preferably 5 to 15 μm.

The pressure-sensitive adhesive sheet is generally used in addition to a method in which a pressure-sensitive adhesive is applied to the release-treated surface of a releasable support or the back surface of a surface base material by a solution or emulsion coating method, and these are stuck together. Manufactured by the method.

In the present invention, the (A) layer and the (C) layer
The heat shrinkage property of the layer film is of utmost importance. In order to prevent curling from occurring during printing on a printer, the heat shrinkage at the film temperature (usually 175 ° C) at the fixing roll temperature (usually 180 to 200 ° C) at the time of printing fixation is determined by the formulas (I) and (II). It is necessary to be within the range.

[0020]

[Equation 3]

When HS (C) exceeds 1.5%, when printing by a printer, especially a laser beam printer,
Curling due to heat cannot be zero. Also, HS
(C) is preferably 1.2% or less, more preferably 1.0% or less. When the absolute value of the difference between HS (A) and HS (C) exceeds 0.7%, HS (C) becomes 1.5.
Even if it is less than%, curling due to heat is likely to occur. Also,
This value is preferably 0.5% or less, most preferably 0%.

The method of producing the heat shrinkage of the (A) layer film and the (C) layer film at the film temperature (usually 175 ° C.) at the time of printing fixation so as to satisfy the above range is arbitrary, but at a specific temperature, It can be obtained by a method of pre-heating each of the films with a combination of tensions.

[0023]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1 As the surface base material layer (A), a white polyester film having cavities inside (Crisper G type, manufactured by Toyobo Co., Ltd.) of 50 μm and having HS (A) = 0.8% was used. As the releasable support layer (C), a silicone resin coat on one side and a matte coat on the other side of a semi-transparent void-containing polyester film (Crisper H manufactured by Toyobo Co., Ltd.).
Type) 75 μm with HS (C) = 1.0% was used. These were stuck together using an acrylic copolymer pressure-sensitive adhesive to obtain a pressure-sensitive adhesive sheet. A4 the obtained adhesive sheet
Using a laser beam printer, Canon Laser Shot B604D (fixing roll temperature at the time of printing fixing of about 180 to 200 ° C), with the surface base material layer (A) side as the upper surface (printing surface) Then, a printing test was conducted. The obtained print sample was placed on a horizontal plane plate, and the height (mm) of lifting from the square plane plate was measured. The result is that the height is 0 mm.
I didn't curl at all.

Example 2 An adhesive sheet was obtained in the same manner as in Example 1. However, the following were used as the surface base material layer (A) and the releasable support layer (C). Surface base material layer (A): HS (A) 1.5%, Crisper G
Type, 50 μm Releasable support layer (C): HS (C) 1.0%, Crisper H type, 50 μm A printing test was conducted on the pressure-sensitive adhesive sheet in the same manner as in Example 1 to measure the rising height. When I did it 0.
It was 5 mm.

Comparative Example 1 An adhesive sheet was obtained in the same manner as in Example 1. However, the following were used as the surface base material layer (A) and the releasable support layer (C). Surface base material layer (A): HS (A) 1.9%, Crisper G
Type, 50 μm Releasable support layer (C): HS (C) 1.1%, Crisper H type, 75 μm A printing test was performed on the pressure-sensitive adhesive sheet in the same manner as in Example 1, and the height of its rise was measured. Done 53
It was mm.

Comparative Example 2 An adhesive sheet was obtained in the same manner as in Example 1. However, the following were used as the surface base material layer (A) and the releasable support layer (C). Surface base material layer (A): HS (A) 1.9%, Crisper G
Type, 50 μm Releasable support layer (C): HS (C) 2.1%, matte-coated polyethylene terephthalate film, 50
μm A printing test was conducted on the pressure-sensitive adhesive sheet in the same manner as in Example 1, and the floating height was measured and found to be 63.
It was mm.

[0028]

The pressure-sensitive adhesive sheet of the present invention hardly curls even when exposed to high temperatures. Therefore, in the toner fixing type printing of a laser beam printer or the like, the fixing roll temperature (for example, 180
The pressure-sensitive adhesive sheet hardly curls even after passing through (about 200 ° C.) and is useful as an adhesive label or the like.

Claims (1)

[Claims] 1. A pressure-sensitive adhesive sheet comprising a surface base material layer (A), a pressure-sensitive adhesive layer (B) and a releasable support layer (C),
Both the (A) layer and the (C) layer are made of a plastic film, and the heat shrinkage characteristics of the (A) layer film and the (C) layer film at 175 ° C. for 2 minutes are represented by the following formulas (I) and (II). ) Are both satisfied. [Equation 1] [However, HS (A): the average value (%) of the heat shrinkage ratio in one direction of the film for the surface base material layer in 175 ° C. × 2 minutes and the direction perpendicular thereto, and HS (C): 175 ° C. × 2 minutes It is the average value (%) of the heat shrinkage in one direction of the releasable support layer film and in the direction perpendicular thereto. ]