JPH11293596A - Pressure sensitive adhesive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a pressure sensitive adhesive sheet capable of preventing the operating efficiency from deteriorating without causing a waste break and a punched label entrained by waste when carrying out the removal of the waste in label processing. SOLUTION: This pressure sensitive adhesive sheet has 550-800 mN tearing strength in the long grain of a surface substrate and 450-650 mN tearing strength in the short grain thereof according to JIS P 8116, 4.0-6.0 kN/m tensile strength in the long grain and 2.5-5.0 kN/m tensile strength in the short grain according to JIS P 8113 and 40-100 gf/50 mm force (peel force) at 150 m/min peel rate when peeling an upper paper comprising the surface substrate and a tacky agent layer from a release paper comprising a release agent layer and a release substrate in the tacky sheet prepared by successively laminating a surface substrate on the tacky agent layer, the release agent layer and the release substrate. The surface substrate is a cast coated paper and the release agent layer comprises a silicone resin. Furthermore, the silicone resin is a solventless type.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a pressure-sensitive adhesive sheet. More specifically, the present invention relates to a pressure-sensitive adhesive sheet having excellent workability such as punching.

[0002]

2. Description of the Related Art In recent years, pressure-sensitive adhesive sheets have been widely used as labels, stickers, seals, patches, delivery slips, etc. for commercial, industrial, and home use with the progress of the information society. Such a pressure-sensitive adhesive sheet has a pressure-sensitive adhesive layer formed between a surface base material and a release sheet, and usually uses paper, a film, a metal foil, or the like as the surface base material. In recent years, film production has steadily grown, but paper still represents the bulk of the surface substrate.

[0003] Further, as a release sheet, a sheet obtained by applying a release agent such as a silicone compound or a fluorine compound to a high density base paper such as glassine paper, clay coated paper, polyethylene laminated paper or the like is widely used. Solvent type, emulsion type, hot melt type and the like are used as the adhesive. Among them, acrylic emulsion type is usually used from the viewpoint of safety and quality.

As a release agent for the pressure-sensitive adhesive sheet, there are silicone resin, fluororesin, aminoalkyd resin, polyester resin and the like, and it is used as an emulsion type, a solvent type or a non-solvent type. Usually, a silicone resin is used. .

In recent years, pressure-sensitive adhesive sheets have come to be punched at high speed and in complicated forms, especially for commercial and industrial labels. For this reason, when removing the cake at the time of label processing, a lot of chips are generated and the workability is reduced.

[0006] For the above reasons, even when punching at high speed and in a complicated shape, at the time of removing the residue during label processing,
There is a strong demand for a pressure-sensitive adhesive sheet that does not reduce the workability and does not cause residue breakage or body lifting. However, at present, no pressure-sensitive adhesive sheet that can sufficiently satisfy these requirements has been provided.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a pressure-sensitive adhesive sheet which is capable of preventing the workability from being reduced without the occurrence of cut-out of the cake or the rise of the cake when removing the cake at the time of label processing. It is in.

[0008]

Means for Solving the Problems In view of such circumstances, the present inventors have conducted extensive research on surface base materials and release agents, and as a result, have used a surface base material having a specific range of tear strength and tensile strength, and By using a release agent that shows a release force at high speeds in a specific range, an adhesive sheet that can be used without removing chips or lifting when removing labels at the time of label processing and without lowering workability. It was completed and led to the present invention.

The present invention provides a pressure-sensitive adhesive sheet comprising a surface substrate, a pressure-sensitive adhesive layer, a release agent layer, and a release substrate which are sequentially laminated.
The tear strength of the surface base material according to JIS P 8116 is 550 to 800 mN in the vertical direction and 450 to 650 m in the horizontal direction.
N, and the tensile strength according to JIS P 8113 is 4.0 to 6.0 kN / m in the vertical direction and 2.5 to 5.0 in the horizontal direction.
kN / m, and the force (peeling force) when peeling the top paper comprising the surface base material and the pressure-sensitive adhesive layer from the release paper comprising the release agent layer and the release substrate is 40 to 40 at a peeling speed of 150 m / min. An adhesive sheet characterized by being 100 gf / 50 mm.

[0010] The present invention also relates to the pressure-sensitive adhesive sheets, wherein the surface substrate is cast paper.
Furthermore, the present invention relates to each of the above-mentioned pressure-sensitive adhesive sheets, wherein the release agent layer is made of a silicone resin. Furthermore, the present invention relates to a pressure-sensitive adhesive sheet having a release layer formed of a solventless silicone resin.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The surface substrate has a tear strength of less than 450 mN in the longitudinal direction or less than 400 mN in the transverse direction, and a tensile strength of less than 4.0 kN / m in the longitudinal direction and 2.5 kN in the transverse direction. When the ratio is less than / m, at the time of removing the lees during the printing operation, the lees are cut and the workability is reduced. vice versa,
The tearing strength is 800 mN for vertical grain and 650 mN for horizontal grain.
Or the tensile strength is 6.0 kN /
When either one of m and 5.0 kN / m is exceeded, the punching property at the time of printing is inferior, the punching cannot be performed sufficiently, and a rise occurs.

If the high-speed peeling force is less than 40 gf / 50 mm, the body will be lifted when removing the cake, and the workability will be reduced.
If the thickness exceeds 100 gf / 50 mm, the cake may be broken when collecting the cake.

In recent years, the speed of printing presses has been increasing, and
/ Min can be collected at a rate of / min. Since the top paper and the release paper move at the same speed when removing the cake, the 180 ° peel corresponds to 100 to 140 m / min. Peeling speed 150
The evaluation at m / min is an index indicating the suitability for removing the cake during printing.

Regarding the base paper used for the surface substrate according to the present invention, in addition to various wood pulp and waste paper pulp usually used in the papermaking process, a sulfuric acid band, a sizing agent, a paper strength improver, a wet paper strength improver, Dyes, pigments, retention aids, defoamers, dehydration aids, whiteness improvers, pitch control agents, germicides, and the like are appropriately used.

There is no particular limitation on the paper machine for making the surface substrate according to the present invention, and a fourdrinier multi-cylinder paper machine, a fourdrinier Yankee type paper machine, a twin-wire multi-cylinder paper machine, a round net paper machine or the like can be used. Although a paper machine can be used, a twin wire multi-cylinder paper machine is particularly good in formation.

In order to obtain target tear strength and tensile strength, NBKP / LBKP = 0 to 25/100
~ 75, pulp freeness 400 ~ 550ml CSF is required. If the compounding ratio of NBKP exceeds 25, the formation becomes worse and the tensile strength partially decreases. When the pulp freeness falls below 400ml CSF,
Although the target tensile strength is obtained, the target tear strength is hardly obtained, and the pulp freeness is 550 m.
When the value exceeds 1CSF, a target tear strength is obtained, but a target tensile strength is hardly obtained. Also,
By using a paper strength improver or raising the rice tsubo, the desired tear strength and tensile strength can be obtained.

The surface substrate used in the present invention may be any surface substrate having a specific range of tear strength and tensile strength, such as cast coated paper, art paper, coated paper, and high quality paper. And heat-sensitive recording paper, ink-jet paper, thermal transfer image-receiving paper, and the like can be appropriately used. In particular, cast coated paper requires a high air permeability of the base paper due to the casting process, and the generation of chips is high, which has been a problem.

In the present invention, the coating layer of the cast coated paper as the surface substrate can be used by mixing a pigment or an adhesive. For example, the pigment is not particularly limited and may be appropriately selected and used. Examples include inorganic pigments and organic pigments such as kaolin, clay, aluminum hydroxide, heavy calcium carbonate, light calcium carbonate, titanium dioxide, satin white, talc, plastic pigment, zinc oxide, calcium sulfate, and barium sulfate. . Of course, two or more pigments can be used in combination. Examples of the adhesive include modified starch, polyacrylamide-based resin, styrene-butadiene copolymer latex emulsion, styrene-acryl copolymer latex emulsion, and acrylate resin-based resin. Furthermore, in addition to the release agent, if necessary, a dispersant, a water-proofing agent, a lubricant, an antifoaming agent, a coloring agent,
Mixing small amounts of additives such as preservatives does not pose any problem. The cast coated processing may be performed by a conventional method.

As the release agent used in the present invention, a silicone resin, a fluorine resin, an aminoalkyd resin, a polyester resin and the like can be used. Used as a solvent type. As constituents thereof, an organopolysiloxane, an organohydrogenpolysiloxane and a platinum-based catalyst are essential. Conventionally, solvent-type silicone resins have been frequently used in terms of workability and peeling quality. However, in recent years, there has been a demand for switching to an emulsion type or a solventless type in terms of environment and safety of workers.

The organohydrogenpolysiloxane constituting the solventless silicone composition has at least three hydrogen atoms bonded to silicon atoms in the molecule, and from a practical point of view, two ΔSiH atoms in the molecule are used. It is preferred that those having a bond be up to 50% by weight of the total amount, and the remainder be one containing at least three ３SiH bonds in the molecule.

The platinum-based catalyst used for synthesizing the organopolysiloxane used in the present invention may be a known one, such as chloroplatinic acid such as chloroplatinic acid, chloroplatinic acid, or the like. Platinic acid alcohol compounds, aldehyde compounds, and complex salts of chloroplatinic acid with various olefins are exemplified.

The crosslink density required to obtain the target release force is determined by the molecular weight of the organopolysiloxane, the number of vinyl groups in one molecule, the molecular weight of the organohydrogenpolysiloxane, the number of SiH in one molecule, Is determined by the mixing ratio. At this time, the ratio between the vinyl group and SiH in the mixture is generally represented by SiH / Vi. If this value is less than 1, the residual amount of the vinyl group, which is an unsaturated group, increases, which affects peeling.

As the pressure-sensitive adhesive that can be used in the method of the present invention,
For example, an acrylic acid comprising an ethylenically unsaturated carboxylic acid-containing monomer, an alkyl ester monomer of (meth) acrylic acid having 4 to 18 carbon atoms, and another monomer copolymerizable with these monomers. Ester copolymers and the like can be mentioned.

The amount of the ethylenically unsaturated carboxylic acid-containing monomer in the acrylic emulsion type pressure-sensitive adhesive used here is usually 0.1 to 20% by weight, more preferably 0.3 to 2% by weight. %. If it is less than 0.1% by weight, the holding power and cohesive strength of the pressure-sensitive adhesive are inferior, and further the emulsion mechanical stability is inferior. If it exceeds 20% by weight, the reaction of the silicone with the unreacted SiH tends to occur, resulting in heavy peeling over time. The coating amount of the acrylic emulsion type pressure-sensitive adhesive preferably set to ^{10g / m 2 ~40g / m 2} . This is because adhesive strength is insufficient at less than 10 g / m ² ,
Even if it exceeds 40 g / m ² , the adhesive strength is saturated and is economically wasted.

The base material for a release paper according to the present invention includes, for example, casein, dextrin, starch, high density base paper such as glassine, clay coated paper, kraft paper or high quality paper.
Carboxymethyl cellulose, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, polyvinyl alcohol, styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer, ethylene-vinyl chloride copolymer, ethylene-vinyl acetate copolymer, acrylate copolymer If necessary for natural or synthetic resin, etc., a base material provided with a filler layer blended with pigments and other auxiliaries, or poly-laminated paper obtained by laminating synthetic resin such as polyethylene on kraft paper or high-quality paper, or polypropylene And a film such as polyethylene terephthalate, and the like. Among them, it is effective for a base material for release paper on which a synthetic resin is not laminated, such as glassine paper and clay coated paper.

As a method for producing a surface substrate according to the present invention, a coating method using a multi-stage roll coater represented by a three-offset gravure coater or a five-roll coater is appropriately used. The amount of the release agent applied is desirably adjusted so as to be in the range of about 0.2 to 2.0 g / m ^{2 on} one side by dry weight. If it is less than 0.2 g / m ² , a pinhole may be formed in the release agent layer, and the release agent layer may have a pinhole of 2.0 g / m ^2.
If it exceeds m ² , the release agent is saturated.

[0027]

The present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited by these examples. Unless otherwise specified, “parts” in each example indicates “parts by weight” of the solid content or the active ingredient.

Example 1 (1) Surface base material The pulp composition was NBKP / LBKP = 0/100, beaten to a freeness of 520 ml, and 100 parts of the pulp was subjected to a paper strength improver (Polystron 117: Arakawa Chemical Co., Ltd.). 0.5 parts, cationized starch (Ace K-100: manufactured by Oji Cornstarch) 0.3 part, talc (SW-B:
8.5 parts of Asahi Flour Milling Co., Ltd.), a high-quality paper of 84.6 g / m ² per square meter was prepared using a twin-wire multi-cylinder paper machine as a surface substrate. (2) Adhesive sheet Solvent silicone (SRX-
345: Dow Corning Toray Silicone Co.) was applied at 1.0 g / m ² to obtain a release paper. Then, a pressure-sensitive adhesive (AT-548: manufactured by Seiden Chemical Co., Ltd.) was applied to the silicone-coated surface of this release paper at a concentration of 30 g / m ² to obtain a pressure-sensitive adhesive sheet bonded to the surface substrate.

A predetermined piece of paper was prepared from the above-mentioned release paper, and the tear strength, the tensile strength, the peeling force, and the suitability for removing cake were measured and evaluated by the following methods.

(1) Tear strength According to JIS P 8116. (2) Tensile strength According to JIS P 8113. (3) Peeling force The adhesive sheet is 300 mm with the long side in the flow direction of the paper machine.
X50mm sample was prepared and high-speed peeling tester Ima
The peeling force when peeling at a tensile angle of 180 degrees in the flow direction under the test conditions of ss ZPE-1000 at a peeling speed of 150 m / min was measured.

(4) Suitability for removing cakes A roll having a width of 180 mm of adhesive paper is used as a letterpress rotary printing machine SKP.
Speed of 60m / min at -250A (manufactured by Miki Co., Ltd.)
To remove cake (168mm x 125mm: 6m of cake part side)
m, a flow of 4 mm) to evaluate the presence or absence of paper breakage in the cake portion and, in the case of cake breakage, the rate of cake breakage occurrence.・ ・ ・: No debris is generated even at a speed of 60 m / min. Δ: Drainage occurs at a speed of 60 m / min. ×: Debris is generated before the speed reaches 60 m / min. Table 1 shows the test results.

(5) Suitability for lifting The roll having a width of 180 mm on the adhesive paper is used as a letterpress rotary printing machine SKP.
Speed of 60m / min at -250A (manufactured by Miki Co., Ltd.)
Was carried out (15 mmφ width direction interval 10 mm, flow direction interval 10 mm) to evaluate the presence or absence of body lift. ○ ・ ・ ・ No rise. △ ・ ・ ・ Slight rise. (Occurrence rate: 5% or less) ×: Uplift occurred. (The occurrence rate exceeds 5%.) The test results are shown in Table 1.

Example 2 A surface substrate and an adhesive sheet were prepared in the same manner as in Example 1,
The evaluation test was performed. However, the pulp composition of Example 1 was NBKP / LBKP = 20/80. Table 1 shows the test results.

Examples 3 and 4 In Example 3, a surface base material and an adhesive sheet were prepared in the same manner as in Example 1 and Example 4, and an evaluation test was performed. However, it was beaten so that the pulp freeness became 450 ml CSF. Table 1 shows the test results.

Examples 5 and 6 In Example 5, a surface base material and an adhesive sheet were prepared in the same manner as in Example 1 and Example 6, and an evaluation test was performed. However, solventless silicone (LTC-1053L: manufactured by Dow Corning Toray Silicone Co., Ltd.) was applied to glassine paper at 1.0 g / m ² with a five-roll coater to obtain a release paper. Table 1 shows the test results.

Example 7 A surface substrate and an adhesive sheet were prepared in the same manner as in Example 1,
The evaluation test was performed. However, kaolin (UW-90: ENGELLH) is used as a pigment on high quality paper as a surface base material.
ARD) and calcium carbonate (MP-55)
5: Maruo calcium) 40 parts, SBR as binder
(LACSTAR2800A: Dainippon Ink and Chemicals, Inc.)
8 parts, other milk proteins (acid casein: BONLA
C) 10 parts of stearic acid was added as a release agent, and cast coated paper was obtained by a wet method. Table 1 shows the test results.

Comparative Example 1 A surface substrate and an adhesive sheet were prepared in the same manner as in Example 1,
The evaluation test was performed. However, the pulp composition of Example 1 was NBKP / LBKP = 30/70. Table 2 shows the test results.

Comparative Example 2 An adhesive sheet was prepared in the same manner as in Example 1, and an evaluation test was performed. However, the pulp freeness of Example 1 was 3
Beated to 80 ml CSF. Table 2 shows the test results.

Comparative Example 3 An adhesive sheet was prepared in the same manner as in Example 1, and an evaluation test was performed. However, the pulp freeness of Example 1 was 5
Beated to 80 ml CSF. Table 2 shows the test results.

Comparative Example 4 A surface substrate and a pressure-sensitive adhesive sheet were prepared in the same manner as in Example 1.
The evaluation test was performed. However, the release agent of Example 1 was (SD-7333: manufactured by Dow Corning Toray Silicone Co., Ltd.). Table 2 shows the test results.

Comparative Example 5 A surface substrate and a pressure-sensitive adhesive sheet were prepared in the same manner as in Example 1.
The evaluation test was performed. However, the coating amount of the release agent of Example 1 was set to 1.8 g / m ² . Table 2 shows the test results.

Comparative Example 6 A surface substrate and a pressure-sensitive adhesive sheet were prepared in the same manner as in Example 1.
The evaluation test was performed. However, the addition number of the paper strength improver of Example 1 was set to 2 parts. Table 2 shows the test results.

Comparative Example 7 A surface substrate and an adhesive sheet were prepared in the same manner as in Comparative Example 1.
The evaluation test was performed. However, the release agent of Comparative Example 1 was (SD-7333: manufactured by Dow Corning Toray Silicone Co., Ltd.). Table 2 shows the test results.

[0044]

[Table 1]

[0045]

[Table 2]

[0046]

As is clear from the results of Tables 1 and 2,
The pressure-sensitive adhesive sheet of the present invention uses a surface substrate having a specific range of tear strength and tensile strength, and, by using a release agent showing a release force at a high speed in a specific range, when removing debris during label processing. It is a pressure-sensitive adhesive sheet capable of preventing the workability from being reduced without the occurrence of cutting out of the cake and the appearance of the body.

Claims (4)

[Claims] 1. A pressure-sensitive adhesive sheet comprising a surface substrate, an adhesive layer, a release agent layer, and a release substrate laminated in this order, wherein the tear strength of the surface substrate according to JIS P 8116 is 550 in the vertical direction.
８００800 mN, 450-650 mN in the horizontal direction, and the tensile strength according to JIS P 8113 is 4.0 to 4.0 in the vertical direction.
6.0 kN / m, and 2.5 to 5.0 kN / m in width.
The force (peeling force) when peeling the top paper comprising the surface substrate and the pressure-sensitive adhesive layer from the release paper comprising the release agent layer and the release substrate is 40 to 10 at a peeling speed of 150 m / min.
A pressure-sensitive adhesive sheet having a thickness of 0 gf / 50 mm. 2. The pressure-sensitive adhesive sheet according to claim 1, wherein said surface substrate is cast coated paper. 3. The pressure-sensitive adhesive sheet according to claim 1, wherein the release agent layer comprises a silicone resin. 4. The pressure-sensitive adhesive sheet according to claim 1, wherein the silicone resin is a solventless type.