JPH04293983A - Double-side self-adhesive sheet having no base material - Google Patents

Abstract

PURPOSE:To obtain the title sheet excellent in the prevention of bleeding between release sheets and suitability for cutting by laminating a specified release sheet peelable by a smaller force, a specified self-adhesive, and a specified release sheet peelable by a greater force. CONSTITUTION:The title sheet is produced by putting together the surface of a self-adhesive layer 3 formed by the hot-air drying of a self-adhesive applied to a release layer 2 of a release sheet 6 peelable by a smaller force and the surface of a release agent layer 4 of another release sheet 7 peelable by a greater force. The self-adhesive is one having a tensile strength of at least 3 kg/cm<2> and an elongation of at most 600%, measured according to JIS K6301. The peel force of the release sheet 6 ranges from 5 to 100g, and that of the release sheet 7 from 20 to 500g, with the ratio of the former to the latter ranging from (1:2) to (1:50) at a peeling rate of 0.3-20 m/min.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a base material-less double-sided adhesive sheet that is useful for adhering nameplates, attaching photos to albums, attaching cutouts of gravure pages of magazines, etc., and for attaching surfaces between objects. In particular, the present invention relates to a base material-less double-sided pressure-sensitive adhesive sheet that suppresses oozing of pressure-sensitive adhesive between release sheets and has excellent cutting suitability for slitter, guillotine, die-cut, and the like.

0002

2. Description of the Related Art Conventionally, double-sided adhesive tapes or adhesive sheets have been used to bond objects together. Such double-sided adhesive tapes or adhesive sheets are usually made of nonwoven fabric, cloth,
An adhesive is applied to both sides of a core base material such as a plastic film or foam, and one or both sides are protected by release paper. Recently, such double-sided adhesive sheets or tapes have become widely used because they can be placed between arbitrary objects and can be applied efficiently and easily by simply pressing and completing the adhesion work. became.

[0003] In recent years, from the viewpoint of reducing the layer thickness of double-sided adhesive sheets (or tapes), or saving resources and energy, double-sided adhesive sheets without a base material (without using a core material), without using a core such as so-called non-woven fabric, have been developed. Double-sided pressure-sensitive adhesive sheets made of only a pressure-sensitive adhesive have begun to be provided. As mentioned above, since a base material-less double-sided adhesive sheet does not use a base material as a core, during the manufacturing process, the pressure at the time of winding causes the adhesive to ooze out to the side of the winding, and as a result, the adhesive oozes out around it. This causes stickiness, giving operators and users a sense of discomfort or discomfort, or the attachment of fine dust in the air, which impairs the appearance of the product, so extreme care must be taken when storing and transporting it. Furthermore, the finished double-sided adhesive tape or adhesive sheet is subjected to a cutting process such as a slitter, guillotine, die cut, etc. to a required size as appropriate depending on the use. In this case, the adhesive tends to adhere to the slitter, guillotine cutting blade, die-cutting blade, etc., resulting in a reduction in cutting efficiency.

0004

[Problem to be solved by the invention] From the above-mentioned actual situation,
The inventors of the present invention conducted intensive research to counter this problem, and as a result,
It has been found that the above-mentioned difficulties can be overcome very efficiently by using an adhesive having a specific tensile strength and elongation rate, and by using different release papers having a specific range of release force.

[0005]

[Means for Solving the Problems] The present invention provides a base material-less double-sided adhesive sheet formed by laminating a release sheet with a light peeling force, an adhesive, and a release sheet with a heavy peeling force. is 3 kg/cm2 or more, and the elongation rate is 600% or less, and (b) the peeling force of a release sheet with a light peeling force is 5 to 100 g, and the peeling force of a release sheet with a heavy peeling force is 20 to 500 g. , and the ratio of both peeling forces is in the range of 1:2 to 1:50.

[0006]

[Function] In general, adhesives used in base-less double-sided adhesive sheets include rubber-based, acrylic-based, vinyl ether-based emulsions, and solvent or solvent-free adhesives. Among these, those containing an acrylic emulsion as a component are particularly preferred. The adhesive is usually applied to a release sheet after adjusting the viscosity to about 3,000 to 8,000 centipoise by adjusting the molecular weight of the acrylic ester, diluting with water, or increasing the viscosity. In this case, the coating device used is, for example, a roll coater, knife coater, bar coater, slot die coater, etc., and the coating amount is 5 to 50 g/dry weight.
It is adjusted within a range of about m2.

The release sheet may be, for example, glassine paper, pigment-coated paper coated with a release agent, kraft paper, polyethylene laminate paper coated with a release agent, polypropylene film, polyethylene terephthalate, etc. A resin film such as a film coated with a release agent is appropriately used.

[0008] As the release agent, generally known and publicly available silicone resins or non-silicone resins such as long chain alkyl acrylate polymer resins are used. The coating amount of the release agent is adjusted to about 0.05 to 3 g/m2 in terms of dry weight, and the release agent layer is finished by heat curing, ionizing radiation curing, etc. In addition, as a coating device when coating a release agent on a base material, for example, a direct gravure coater, a Meyer bar coater, an air knife coater,
Offset gravure coaters, multi-stage roll coaters, etc. are used.

Thus, as shown in FIG. 1, the base material-less double-sided adhesive sheet of the present invention has an adhesive layer (3) formed by drying the adhesive coated on one release sheet (6) with hot air.
It is manufactured by bonding the surface and the surface of the release agent layer (4) of the other release sheet (7). As mentioned above, due to the pressure during the manufacturing process, that is, during winding, the adhesive may seep out to the side of the winding, or when cutting the double-sided adhesive sheet, the adhesive may adhere to the processing blade. As a result, there is a problem that the efficiency of the cutting process decreases.

As mentioned above, the present invention provides a base material-less double-sided pressure-sensitive adhesive sheet that solves the problems of conventional base-free double-sided pressure-sensitive adhesive sheets. Tensile strength measured according to K6301 is 3 kg/cm2 or more, and elongation rate is 6
It has been found that the above-mentioned difficulties can be solved extremely efficiently by specifying the ratio to be 0.00% or less. Incidentally, if the tensile strength is less than 3 kg/cm2 or the elongation rate exceeds 600%, the adhesive will seep out to the side of the roll when creating a roll of the base material-less double-sided adhesive sheet, and the slitter will , guillotine, die-cutting, etc., the adhesive adheres to the cutting blade severely, resulting in a significant decrease in work efficiency, which is a problem.

Furthermore, the double-sided adhesive sheet of the present invention has the purpose of preventing the adhesive layer from following and turning up when one release paper is peeled off from the adhesive layer for the purpose of adhering to another object. One side of the adhesive layer is coated with a release agent layer having a light release force, and the other side is coated with a release agent layer having a heavy release force. At this time, the difference in peeling force between both release papers is relative, and the larger the difference is, the better, regardless of the peeling speed.On the other hand, if the difference in peeling force between both release papers is too large, the peeling force will be heavy. It becomes difficult to remove the release paper. Preferred specific peeling forces for both are 5 to 100 g for a release paper with a light peeling force, and 20 to 500g for a release paper with a heavy peeling force; The force ratio is changed to the peeling speed of 0.3 m/min to 2
The desired effect can be obtained by setting the ratio within the range of 1:2 to 1:50, preferably within the range of 1:3 to 1:20, up to 0 m/min. A cross-sectional view (FIG. 1) of the base material-less double-sided pressure-sensitive adhesive sheet of the present invention is shown below.

0012

[Examples] The present invention will be explained in more detail with reference to Examples below, but the present invention is of course not limited to these.

Example 1 Light release silicone KS-770 (manufactured by Shin-Etsu Chemical Co., Ltd.) and heavy release silicone BY24-312 (Toray Dow Corning Co., Ltd.) were applied to the surface of polyethylene laminated paper.
(manufactured by Silicone Co., Ltd.) each in terms of solid content of 0.5
g/m2 coating and drying with hot air to obtain a release paper with a light release force and a release paper with a heavy release force. Acrylic emulsion type adhesive
-490 -229 E (manufactured by Saiden Chemical Co., Ltd.) was coated using a roll coater to give a solid content of 20 g/m2, dried with hot air, and peeled off so that the adhesive layer and release agent layer were in contact. A base material-less double-sided pressure-sensitive adhesive sheet was obtained by laminating a heavy-duty release paper.

Example 2 Heavy release silicone SRX - for release paper with heavy release force
345 (Toray Dow Corning Silicone Co., Ltd.)
A base material-less double-sided pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1, except that a double-sided pressure-sensitive adhesive sheet was used.

Example 3 X-490 as an acrylic emulsion type adhesive
A base material-less double-sided adhesive sheet was obtained in the same manner as in Example 1, except that -228E (manufactured by Saiden Chemical Co., Ltd.) was used.

Comparative Example 1 X-490 as an acrylic emulsion type adhesive
A base material-less double-sided adhesive sheet was obtained in the same manner as in Example 1, except that -213E (manufactured by Saiden Chemical Co., Ltd.) was used.

Comparative Example 2 X-490 as an acrylic emulsion type adhesive
A base material-less double-sided adhesive sheet was obtained in the same manner as in Example 1, except that -226 E (manufactured by Saiden Chemical Co., Ltd.) was used.

Comparative Example 3 Light release silicone KS-85 was used for release paper with heavy release force.
Example 1 except that 7 (manufactured by Shin-Etsu Chemical Co., Ltd.) was used.
A base material-less double-sided adhesive sheet was obtained in the same manner as above.

Table 1 shows the tensile strength, elongation rate, oozing of the adhesive layer, suitability for cutting, and the peeling force and peelability of the release paper of each base material-less double-sided adhesive sheet thus obtained.
It was shown to. The tensile strength, elongation rate, exudation of the adhesive, suitability for cutting, and the peeling force and releasability of the release paper were evaluated as follows.

[Tensile strength of adhesive] JIS K630
The maximum load up to the time of cutting the adhesive piece was measured according to the tensile strength measurement method specified in Section 1. (unit;
kg/cm2)

[Elongation rate of adhesive] JIS K6301
The elongation rate of the adhesive piece up to the time of cutting was measured according to the elongation rate measurement method specified in . Specifically, it is based on the following formula. E=100(L1-L0)÷L0 Here, E;
Elongation rate (%), L0; Gauge line distance (mm), L1; Gauge line distance at cutting (mm)

[Peeling force] After pasting Nitto 31B tape on release paper to create a 50 mm wide test piece, the peeling force is applied when the tape is peeled off from the release paper at a predetermined speed and at a pulling angle of 180°. The load was measured. (Unit: g/50mm)

[Bleeding of adhesive] Cut the adhesive sheet into a length of 5
cm, width 5cm, stack 100 pieces and weigh 0.1 kg
After processing for 72 hours under a load of /cm2 at a temperature of 50° C. and a humidity of 95% RH, the amount of adhesive exuding from the side surface was visually determined. "◎; Adhesive oozing is not observed. ○: Slight oozing is observed, but there is no practical problem. △; Slight oozing is observed, which is a slight problem for practical use. ×: Severe oozing , which is a practical problem."

[Cutting processability] Cut the adhesive sheet to a length of 20 cm.
, cut into 15 cm wide sheets, stacked 100 sheets, and cut them 20 times in the width direction using a guillotine test machine "CM-450" (manufactured by Rokugo Seisakusho Co., Ltd.). The amount was visually determined. "◎: Adhesion of adhesive is not observed. ○: Adhesion of adhesive is slightly observed, but at a level that does not pose a practical problem. △: Adhesion of adhesive is observed, which is a slight problem for practical use. ×: Adhesion The adhesion of the agent is severe, which is a practical problem.

[0025]
[Releasability] In accordance with the releasability test method for double-sided pressure-sensitive adhesive tapes specified in JIS Z1528, a test was conducted to determine whether or not the release paper could be easily peeled off. "○: Can be easily peeled off. ×: Tracking of the adhesive layer is observed, which is a practical problem."

[0026]

[Table 1]

[0027]

[Effects of the Invention] As is clear from Table 1, the examples of the present invention were substrate-less double-sided pressure-sensitive adhesive sheets that were satisfactory in both the properties of suppressing adhesive oozing and cutting suitability.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a base material-less double-sided pressure-sensitive adhesive sheet according to the present invention.

[Explanation of symbols]

(1) ...Base material sheet (2)...Release agent layer with light peeling force (3)...Adhesive layer (4)...Release agent layer with heavy peeling force (5)... Base sheet (6) Release sheet with light peeling force (7) Release sheet with heavy peeling force

Claims (1)

[Claims] Claim 1: A base material-less double-sided adhesive sheet formed by laminating a release sheet with a light release force, an adhesive, and a release sheet with a heavy release force, wherein (a) the adhesive has a tensile strength of 3 kg/c;
m2 or more, and the elongation rate is 600% or less, and (b) the peeling force in a release sheet with a light peeling force is 5 to 5.
100g, the peeling force on a release sheet with a heavy peeling force is 20 to 500g, and the ratio of both peeling forces is 1:2 to
A base material-less double-sided adhesive sheet characterized by having a ratio of 1:50.