JPH0776674A - Strippable liner and tacky member - Google Patents

Abstract

PURPOSE:To obtain a strippable liner capable of being recycled by regeneration, having slight dimensional change caused by moisture absorption, having excellent hand cutting properties in the case of processing into a tacky member, comprising a releasability imparting layer on a paper substrate subjected to surface treatment with a vinylidene chloride-based copolymer film. CONSTITUTION:The liner has a releasability imparting layer 3 on a paper substrate 1 subjected to surface treatment with a film 2 of a vinylidene chloride- based copolymer (preferably one comprising 80-92wt.% of vinylidene chloride unit content, having 100,000-400,000 weight-average molecular weight). The film 2 is preferably formed by coating the surface of the paper substrate 1 with a vinylidene chloride-based copolymer latex or emulsion in 1-20mum thickness. The releasability imparting layer 3 is preferably formed by using a radiation-curing silicone-based release agent in terms of adhesivity to the film 2 and prevention of occurrence of pinholes. The thickness of the releasability imparting layer 3 is preferably 0.05-5mum, generally.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper-based release liner which is less likely to cause dimensional change due to moisture absorption and is useful for effective utilization of earth resources by recycling and environmental protection, and an adhesive member using the same.

[0002]

2. Description of the Related Art Conventionally, as a release liner for a paper base material as a support base material or a coating layer for an adhesive layer in an adhesive member, paper made of high-quality paper, glassine paper, kraft paper or the like, or paper made of melamine resin is used. It has been known that a resin coated with an epoxy resin or a film laminated with a plastic film such as polyethylene or polyester and having a surface treated with a release agent.

Such paper-based release liners are often used as backing materials for kraft tapes and masking tapes, double-sided adhesive tapes, adhesive sheets, release papers for protecting the adhesive surface of adhesive labels, and the like. The moisture absorption state is likely to change depending on the outside air conditions such as humidity and humidity,
As a result, the dimensions are variously changed, which causes various problems such as wrinkles, gapping, telescoping, tunneling, and blocking in the adhesive component.

Therefore, although measures such as humidity control and aging of the paper base material have been taken, it is not a sufficient improvement measure. Even for paper-based substrates laminated with polyethylene film, etc., pinholes may be generated during the application of release agents and adhesives, hand-cutability of adhesive members may be reduced, and recycling by recycling is difficult. However, it has been a long-standing problem to provide a satisfactory paper-based release liner.

[0005]

DISCLOSURE OF THE INVENTION The present invention is such that dimensional changes due to moisture absorption and pinholes are less likely to occur at the time of applying a release agent and the like, and they have good hand-cutability when used as an adhesive member. An object is to obtain a releasable paper-based release liner.

[0006]

DISCLOSURE OF THE INVENTION The present invention provides a paper whose one or both surfaces are surface-treated with a superposed film of a vinylidene chloride copolymer film or a rubbery polymer film and a vinylidene chloride copolymer film inside. It is intended to provide a release liner having a release property imparting layer on a base material, and an adhesive member comprising an adhesive layer coated with the release liner.

[0007]

[Function] A paper liner-based release liner that is surface-treated with a vinylidene chloride-based copolymer film to prevent dimensional changes due to moisture absorption and pin holes during application of release agents, etc. Can be obtained. Further, by interposing a rubber-like polymer film between the vinylidene chloride-based copolymer film and the paper base material, the above-mentioned characteristics such as dimensional stability can be further improved. Further, by making the surface treatment layer have a predetermined thickness, it is possible to disaggregate even by a simple operation such as high speed stirring in water, and the paper can be recycled for recycling. Therefore, by using such a paper-based release liner, it is possible to obtain an adhesive member that is unlikely to cause wrinkles, gapping, telescoping, tunneling, blocking, and the like.

[0008]

EXAMPLE A release liner of the present invention is a paper substrate whose one side or both sides are surface-treated with a superposed film having a vinylidene chloride copolymer film or a rubbery polymer film inside and a vinylidene chloride copolymer film. On top of which a peelability-imparting layer is provided. Examples are shown in FIGS. 1 and 2. 1 is a paper base material, 2 is a vinylidene chloride-based copolymer film, 3 is a release property-imparting layer, and 4 is a rubber-like polymer film.

As the paper base material, conventional paper such as high-quality paper, glassine paper and kraft paper can be used.
The thickness may be appropriately determined depending on the purpose of use and the like, but is generally 1 mm or less, and preferably 5 to 500 μm.

The vinylidene chloride-based copolymer film can be formed by using various copolymers containing vinylidene chloride as a main component, and any commercially available one can be used as the copolymer. Therefore, the copolymerization component other than vinylidene chloride may be various ones such as vinyl chloride and acrylonitrile.

The vinylidene chloride copolymer preferably used has a vinylidene chloride unit content of 80 to 92% by weight.
The weight average molecular weight is 100,000 to 400,000. Such copolymers are Saran Latex L-502,
508 (trade name, manufactured by Asahi Kasei Corp.) and the like.

In the above, when the content of vinylidene chloride units is less than 80% by weight or the weight average molecular weight is less than 100,000, the vinylidene chloride copolymer film to be formed is apt to have pinholes and the moisture-proof effect is insufficient. Therefore, the release liner may have poor dimensional stability. On the other hand, when the content of the vinylidene chloride unit exceeds 92% by weight, a film which is brittle and easily causes pinholes may be formed, and when the weight average molecular weight exceeds 400,000, when the coating solution is used, especially latex In that case, the film-forming property of the particles may be deteriorated and a film having a poor moisture-proof effect may be formed.

The vinylidene chloride copolymer film is formed by forming the vinylidene chloride copolymer film into an appropriate coating liquid form such as a solution with a latex or a solvent as described above, and applying it to a paper substrate surface or a paper substrate surface. It can be carried out by coating on a rubber-like polymer film to form a coating film. As the above-mentioned form of the coating liquid, latex or emulsion is generally preferable in view of workability and quality of the release liner.

The thickness of the vinylidene chloride copolymer film formed is preferably 1 to 20 μm. Further, such a copolymer film preferably has an elongation rate of 10 to 100%. If the thickness is less than 1 μm or the elongation is less than 10%, pinholes are easily generated in the copolymer film, the moisture-proof effect becomes insufficient, and the release liner may have poor dimensional stability. On the other hand, when the thickness exceeds 20 μm, the rigidity of the release liner becomes too large, and it may be unnecessarily peeled off from the adhesive surface due to curling, and the elongation is 10%.
If it exceeds 0%, blocking may occur in a state of being coated on paper and wound into a roll.

In the present invention, the rubber-like polymer film is provided as a sealing material on the surface of the paper base material if necessary for the purpose of forming a release liner without pinholes. The attachment is especially effective. Therefore, the rubber-like polymer film is provided between the paper base material 1 and the vinylidene chloride copolymer film 2 as illustrated in FIG.

In forming the rubber-like polymer film, the rubber-like polymer is formed into an appropriate coating liquid such as a solution of latex or solvent,
It can be carried out by applying it to the surface of the paper substrate to form a coating film. As the form of the coating liquid, latex or emulsion is generally preferable in view of workability and quality of the release liner.

The thickness of the rubber-like polymer film formed is 1 to 2
0 μm is preferred. If the thickness is less than 1 μm, the release liner may be poor in dimensional stability because pinholes and defects are likely to occur, and if it exceeds 20 μm, the release liner becomes too rigid and curls or other problems may cause the release liner to become less stable than the adhesive surface. It may come off if necessary.

For forming the rubber-like polymer film, for example, chloroprene rubber, urethane type polymer, acrylic polymer, SB type rubber or the like can be used. In addition, it is synthesized by using one or more kinds of monomers including unsaturated carboxylic acid ester, aromatic vinyl compound, unsaturated carboxylic acid, vinyl cyanide compound, aliphatic diene, halogen-substituted vinyl compound, carboxylic acid vinyl ester and the like. Polymers etc. may also be used.

Specific examples of the above-mentioned unsaturated carboxylic acid ester include methyl methacrylate, butyl acrylate,
2-ethylhexyl acrylate, glycidyl methacrylate, 2-hydroxyethyl acrylate, methacrylic acid 2
-Hydroxyethyl, diethylene glycol diacrylate, trimethylolpropane triacrylate and the like can be mentioned.

Specific examples of the aromatic vinyl compound include styrene, vinyltoluene and divinylbenzene, and specific examples of the unsaturated carboxylic acid include acrylic acid and
Methacrylic acid, itaconic acid, maleic acid, fumaric acid, and the like, and specific examples of the vinyl cyan compound include acrylonitrile, methacrylonitrile, and the like.

Further, specific examples of the aliphatic diene include butadiene and isoprene, specific examples of the halogen-substituted vinyl compound include vinyl chloride, and specific examples of the carboxylic acid vinyl ester include vinyl acetate and the like, vinylamide. Specific examples of the compound include acrylamide,
Examples thereof include N-methylol acrylamide.

The latex of the polymer composed of the above-mentioned monomers is obtained by an appropriate method such as a method of emulsion-polymerizing one or more kinds of monomers by a known method using a polymerization initiator or an emulsifier. be able to. A rubber-like polymer that can be preferably used in terms of adhesion to a vinylidene chloride-based copolymer film is a butadiene-based polymer such as SBR, (meth)
For example, an acrylic polymer whose main component is an acrylic ester.

In the present invention, a coating film in which two or more kinds of rubber-like polymers are mixed can be prepared by mixing two or more kinds of latex, but a preferable rubber-like polymer film is soft. In particular, the growth rate is 10% or more,
Particularly, it is 100% or more. If the rubber-like polymer film is too hard, pinholes are likely to occur due to cracking, and the release liner may have poor dimensional stability. In addition, the rigidity may increase and the release liner may unnecessarily peel off.

In the present invention, the vinylidene chloride copolymer film has a thickness of 1 to 1 in order to impart good disintegration by a simple operation such as high-speed stirring in water, and thus to provide smooth papermaking without trouble. It is preferably 7 μm, especially 2 to 5 μm. The thickness of the rubber-like polymer film provided as necessary is preferably 1 to 10 μm, more preferably 1 to 7 μm, and particularly preferably 2 to 5 μm.

In the present invention, the vinylidene chloride-based copolymer film and the rubber-like polymer film may optionally contain a filler such as calcium carbonate, clay, talc, silica, a dispersant thereof, and a thickener. A suitable additive such as a tackifier or a plasticizer can be mixed.

The thickness of the peelability-imparting layer provided on the vinylidene chloride copolymer film can be the same as conventional. Therefore, it is generally 10 μm or less, preferably 0.05 to 5 μm. The release property imparting layer may be formed by using an appropriate release agent such as a long chain alkyl release agent or a fluorine release agent, and a silicone release agent is preferably used.

As the silicone-based release agent, a suitable one such as a thermosetting type such as a solution type, an emulsion type, a solventless type or a radiation curing type such as an ultraviolet ray or an electron beam may be used. Among them, the radiation-curable silicone-based release agent is preferable from the viewpoints of adhesion with the vinylidene chloride-based copolymer film and prevention of pinholes. RC-72 for radiation curable silicone release agents
6, RC-705, RC-711, RC-704, UV
There are commercially available products such as -9300 and UV-2775 (both are trade names, manufactured by Cold Schmidt or manufactured by Toray Silicone).

The pressure-sensitive adhesive member of the present invention has the pressure-sensitive adhesive layer coated with the above-described release liner. Examples thereof are shown in FIGS. 3 and 4. 5 is a release liner, and 6 is an adhesive layer. Figure 3
In FIG. 4, the release liner 5 is used as a support base material for the adhesive layer 6, and in FIG. 4, the release liner 5 is used as a separator 5 for covering and protecting the adhesive layer 6 provided on the support base material 7. The release liner is applied to the adhesive surface via the peelability imparting layer. The adhesive layer to be applied is not particularly limited and may be made of an appropriate adhesive substance such as an acrylic adhesive or a rubber adhesive.

Example 1 SBR latex was coated on one surface of kraft paper with a bar coater to form a rubber-like polymer film having a thickness of 4 μm and an elongation of 1200%, and a vinylidene chloride copolymer latex was formed thereon. 1.5 μm thick with 23% elongation
A vinylidene chloride copolymer film was formed. Then, a radiation-curable silicone release agent was applied onto the vinylidene chloride-based copolymer film and cured with an electron beam of 3 Mrad to form a release-providing layer having a thickness of 1 μm to obtain a release liner. The above vinylidene chloride-based copolymer has a weight average molecular weight of 120,000 and contains 83% by weight of vinylidene chloride units.

Next, S on the kraft paper surface of the release liner.
An IS hot melt adhesive was applied at 40 g / m and wound in a roll to obtain a kraft adhesive tape.

Example 2 According to Example 1, a release liner having a rubber-like polymer film having a thickness of 3 μm and a vinylidene chloride copolymer film having a thickness of 3 μm and a kraft adhesive tape were obtained.

Example 3 According to Example 1, a release liner having a rubber-like polymer film having a thickness of 5 μm and a vinylidene chloride copolymer film having a thickness of 5 μm and a kraft adhesive tape were obtained.

Example 4 According to Example 1, a release liner having a rubber-like polymer film having a thickness of 2 μm and a vinylidene chloride copolymer film having a thickness of 10 μm and a kraft adhesive tape were obtained.

Example 5 In accordance with Example 1, a release liner having a rubber-like polymer film having a thickness of 5 μm and a vinylidene chloride copolymer film having a thickness of 15 μm and a kraft adhesive tape were obtained.

Example 6 According to Example 1, a release liner having a rubber-like polymer film having a thickness of 6 μm and a vinylidene chloride copolymer film having a thickness of 2 μm and a kraft adhesive tape were obtained.

Example 7 In accordance with Example 1, a release liner having a rubber-like polymer film having a thickness of 5 μm and a vinylidene chloride copolymer film having a thickness of 3 μm and a kraft adhesive tape were obtained.

Example 8 According to the same manner as in Example 1, a release liner having a rubbery polymer film having a thickness of 15 μm and a vinylidene chloride copolymer film having a thickness of 2 μm and a kraft adhesive tape were obtained.

Examples 9 to 16 Release liners and kraft adhesive tapes were obtained in the same manner as in Examples 1 to 8 except that an acrylic emulsion was used instead of the SBR latex.

Example 17 Using NBR latex, thickness 3 μm, elongation 1500
%, A release liner and a kraft pressure-sensitive adhesive tape were obtained in the same manner as in Example 2 except that a rubber-like polymer film was formed.

Example 18 Using urethane emulsion, the thickness is 3 μm and the elongation is 2
A release liner and a kraft adhesive tape were obtained in the same manner as in Example 2 except that a 50% rubber-like polymer film was formed.

Example 19 A rubbery polymer film having a thickness of 3 μm and a vinylidene chloride copolymer film having a thickness of 3 μm were formed in the same manner as in Example 2.
The surface of the vinylidene chloride-based copolymer film is subjected to corona discharge treatment, and a thermosetting silicone-based release agent is applied onto the surface and cured by heating at 130 ° C. for 30 seconds to form a 1 μm-thick release property imparting layer. Then, a release liner was obtained, and using it, a kraft pressure-sensitive adhesive tape was obtained according to Example 1.

Examples 20 to 27 A vinylidene chloride copolymer film (elongation: 18%) was formed using a vinylidene chloride copolymer latex containing 85% by weight of vinylidene chloride units and having a weight average molecular weight of 120,000. A release liner and a kraft adhesive tape were obtained according to Examples 1 to 8.

Example 28 The same vinylidene chloride copolymer latex as in Example 1 was used to form a vinylidene chloride copolymer film having a thickness of 3 μm and an elongation of 29% on both sides of glassine paper, and ultraviolet rays were formed thereon. A curable silicone release agent is applied and cured with ultraviolet rays to form a release liner having a thickness of 1 μm on both sides to obtain a release liner. An acrylic pressure-sensitive adhesive layer is provided on one side of the release liner and rolled into a roll. A double-sided adhesive tape was obtained.

Example 29 An acrylic emulsion was applied to both sides of bleached kraft paper to form a rubber-like polymer film having a thickness of 7 μm and an elongation of 980%, and the same vinylidene chloride-based film as in Example 20 was coated on the rubbery polymer film. After forming a vinylidene chloride-based copolymer film with a thickness of 5 μm using polymer latex, a radiation-curable silicone release agent is applied onto it and cured with an electron beam of 2.5 Mrad to a thickness of 1 μm. A release-releasing layer was formed to obtain a double-sided release liner, and a SIS-based hot melt adhesive layer was provided on one surface of the double-sided release liner according to Example 1 to obtain a double-sided adhesive tape.

Comparative Example 1 A vinylidene chloride copolymer film having a thickness of 1.5 μm and an elongation of 3% was prepared using a vinylidene chloride copolymer latex containing 90% by weight of vinylidene chloride units and having a weight average molecular weight of 130,000. A release liner and a kraft pressure sensitive adhesive tape were obtained in the same manner as in Example 1 except that the release liner was formed.

Comparative Example 2 In accordance with Comparative Example 1, a release liner and a kraft adhesive tape having a rubber-like polymer film having a thickness of 3 μm and a vinylidene chloride copolymer film having a thickness of 3 μm were obtained.

Comparative Example 3 According to Comparative Example 1, a release liner and a Kraft pressure-sensitive adhesive tape having a rubber-like polymer film having a thickness of 5 μm and a vinylidene chloride copolymer film having a thickness of 5 μm were obtained.

Comparative Example 4 A double-sided release liner and a double-sided adhesive tape were obtained in the same manner as in Example 29 except that the rubber-like polymer film was not provided.

Evaluation Test The following characteristics of the release liner or pressure-sensitive adhesive tape obtained in Examples and Comparative Examples were examined. Storability The adhesive tape that had been left in an atmosphere of 35 ° C and 80RH% for 7 days and then stored in an atmosphere of 23 ° C and 65RH% for 1 day was observed for wrinkles in the release liner and gapping of the tape. If it is not recognized, it is excellent, wrinkle,
The product with a large degree of gapping and no commercial value was rated as bad, and evaluated in four grades of excellent, good, good, and bad.

Disintegration property The disintegration state of the release liner was observed at the time of stirring the release liner with a TAPPI type disintegration tester for 10 minutes. The evaluation was made in four grades of good, good, good and bad.

Tunneling (TP) Property A double-sided adhesive tape (400 mm × 400 mm) is pressure-bonded to an aluminum plate of the same size, and this is left for 1 day in an atmosphere of 35 ° C. and 80 RH% to observe the tunneling state. ,
Excellent when no abnormalities are recognized, excellent when the degree of tunneling is large and without commercial value is excellent, good,
The evaluation was made on a 4-grade scale of good and bad.

The above results are shown in Table 1, Table 2, Table 3 and Table 4. In addition, x in the table means not possible.

[Table 1]

[0053]

[Table 2]

[0054]

[Table 3]

[0055]

[Table 4]

The samples of Examples 28 and 29 showed no abnormalities in the tunneling test, but the sample of Comparative Example 4 had a bad result. In Comparative Examples 1, 2, and 3, a large number of pinholes were generated in the vinylidene chloride copolymer film, and wrinkles and gapping were generated in the adhesive tape.

[0057]

Since the release liner of the present invention is surface-treated with a vinylidene chloride-based copolymer film, it is a paper base material, has little dimensional change due to moisture absorption, is excellent in long-term dimensional stability, and has good handability. Has sharpness. Furthermore, it can be disintegrated even by a simple operation such as high-speed stirring in water, and it has the property that it can be recycled by recycling the paper. Therefore, such a paper-based release liner makes it possible to obtain an adhesive member that is unlikely to cause wrinkles, gapping, telescoping, tunneling, blocking, and the like.

[Brief description of drawings]

FIG. 1 is a cross-sectional view illustrating a release liner.

FIG. 2 is a cross-sectional view illustrating another release liner.

FIG. 3 is a cross-sectional view illustrating an adhesive member.

FIG. 4 is a cross-sectional view illustrating another adhesive member.

[Explanation of symbols]

1: Paper base material 2: Vinylidene chloride copolymer film
3: Release property imparting layer 4: Rubber-like polymer film 5: Release liner 6: Adhesive layer 7: Support substrate

Claims (6)

[Claims] 1. A release liner having a release property-imparting layer on a paper substrate whose one or both surfaces are surface-treated with a vinylidene chloride copolymer film. 2. A peeling property-imparting layer is provided on a paper base material whose one or both surfaces are surface-treated with a superposed film of a vinylidene chloride copolymer film having a rubbery polymer film inside. Release liner. 3. The rubber-like polymer film is acrylic or SBR.
Consisting of a system latex coating with a thickness of 1 to 20 μm
The release liner according to claim 2. 4. A vinylidene chloride-based copolymer film having a weight average molecular weight of 100,000 to 400,000, containing 80 to 92% by weight of vinylidene chloride units, having a thickness of 1 to 20 μm and an elongation of 10 to 10. The release liner according to claim 1, wherein the release liner comprises a 100% latex coating film, and the release property-imparting layer comprises a radiation-curable silicone-based release agent. 5. The thickness of the vinylidene chloride copolymer film is 1
5. The release liner according to claim 4, which has a thickness of 1 to 7 .mu.m and has a thickness of 1 to 10 .mu.m when it has a rubber-like polymer film. 6. An adhesive member comprising an adhesive layer coated with the release liner according to claim 1.