JPH03243677A - adhesive sheet - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pressure-sensitive adhesive sheet having removability and a method for producing the same.

[Conventional technology] In conventional adhesive sheets such as labels, after being attached to an adherend,
Those that are removable and reusable are widely used. For example, adhesive sheets can be used as memo sheets or sticky notes to write matters or questions, etc. and temporarily attach them to documents, etc., and then be peeled off and discarded when no longer needed. There are known pressure-sensitive adhesive sheets that have removability, such as pressure-sensitive adhesive sheets that can be temporarily bonded and, if the position is incorrect, are peeled off and re-attached, and then permanently bonded.

Such a pressure-sensitive adhesive sheet includes: 1) a pressure-sensitive adhesive sheet in which the pressure-sensitive adhesive layer is partially formed on the base material by adhering the pressure-sensitive adhesive layer in the form of dots on the base material by a method such as printing, and 2) a large number of spherical adhesive microparticles. Adhesive sheets formed by adhering to the surface of a base material through a binder (for example, Utility Model Application No. 54-60661, Utility Model Application No.
-42881), 3) Adhesive sheet in which an adhesive layer is formed by adhering a large number of hemispherical adhesive microparticles to the surface of a base material with their curved surfaces facing outward (for example, Utility Model Publication No. 57-573
94) etc. have been proposed.

[Problem to be solved by the invention]

However, in the adhesive sheets of 1) and 2) above,
When peeled off after being attached to an adherend, the problem is that dot-shaped adhesive and sticky microparticles remain on the adherend, staining the surface of the adherend with the adhesive. there were. In addition, in the adhesive sheet described in 3), since the adhesive has a semicircular shape, the bond between the base material and the adhesive microparticles becomes stronger.
, compared to case 2), the problem of adhesive remaining during peeling can be improved to some extent, but when manufacturing adhesive notebooks, it is necessary to manufacture semicircular spherical adhesive microparticles in advance, and This requires the tedious work of attaching adhesive microparticles to a substrate with the curved surface facing outward. Therefore, the number of manufacturing steps increases, and there is a problem in manufacturing that it is technically difficult to attach the microparticles with all their curved surfaces facing outward.

The present invention solves the above-mentioned drawbacks of the prior art, and provides a removable adhesive that can be peeled off properly without leaving any adhesive on the adherend when peeled from the adherend. The purpose of the present invention is to provide a sheet and a method for manufacturing the same.

[Means for Solving the Problems] The present invention provides: () a pressure-sensitive adhesive base layer of a predetermined thickness is provided on a base material surface, and a large number of pressure-sensitive adhesive convex bodies protrude outward from the surface of the pressure-sensitive adhesive base layer. A pressure-sensitive adhesive sheet having removability, characterized in that it is provided integrally with a pressure-sensitive adhesive base layer.

(2) Apply adhesive to the surface of a release film having a large number of recesses so that the adhesive is filled in the recesses and a pressure-sensitive adhesive base layer of a predetermined thickness is continuously formed on the recesses. 1. A method for producing a pressure-sensitive adhesive sheet having removability, the method comprising: processing the pressure-sensitive adhesive sheet, and then bonding a base material to the surface of the pressure-sensitive adhesive base layer.

The main points are as follows.

The present invention will be explained in detail below based on the drawings.

As shown in FIG. 1, the adhesive sheet 1 of the present invention has a base material 2
and an adhesive layer 3 formed on the surface of the base material 2, and the adhesive layer 3 is composed of an adhesive base N4 provided to a predetermined thickness and a large number of adhesive convex bodies 5 provided so as to protrude outward. formed,
The adhesive base layer 4 and the adhesive convex body 5 are integrally provided from the same material. The horizontal cross-sectional shape of the adhesive convex body 5 may be arbitrary, such as dots, lines, or lattice shapes, and in the case of dots, various shapes such as circular, elliptical, paraboloid of revolution, triangular, quadrilateral, etc. may be used. Although possible, a spherical shape is particularly desirable.

In addition, from the viewpoint of removability, the vertical cross-sectional shape in the protrusion direction is preferably linear or grid-like, with a smooth curved surface or tapered surface formed in the protrusion direction, and semicircular shape is particularly preferable. A preferred three-dimensional shape of the adhesive convex body 5 includes a hemispherical shape.

The size and number of the convex bodies 5 are related to the re-peelability of the adherend. When the number of convex bodies is small and the density is low, sufficient adhesion cannot be obtained, and when the number of convex bodies is large and the density is high, removability tends to deteriorate.

The width of the base of one convex body is usually 1 to 300 μm,
For example, in the case of a hemispherical shape, the diameter is preferably about 1 to 50 μm, and the height of the convex body is 1 to 300 μm. The number of convex bodies varies depending on their size, but the diameter is 1 to 5.
In the case of a hemispherical shape of 0 μm, the number of particles is usually about 1,000 to I 000,000/c4.

In the adhesive sheet of the present invention, by selecting the shape, size, density, type of adhesive, etc. of the adhesive convex body, removability can be optimally adjusted according to the type of adherend. .

The thickness of the adhesive base layer 3 formed integrally with the adhesive convex portion 5 depends on the size of the adhesive convex body 5, but is usually 1 to 1 mm.
00 μm, preferably 10 to 50 μm.

The adhesive layer 3 may be provided on the entire surface of the base material 2 or may be provided partially.

As the adhesive forming the adhesive layer 3, general acrylic adhesives used in conventionally known adhesive tapes and stickers,
A rubber-based adhesive is used, and both solvent-based and emulsion-based adhesives can be used.

For example, polyisoprene rubber, polyisobutylene rubber,
Rubber resins such as styrene-butadiene rubber and butadiene-acrylonitrile rubber, (meth)acrylate resins, polyvinyl ether resins, polyvinyl acetate resins, vinyl chloride vinyl acetate copolymer resins, polystyrene resins, polyester resins A suitable tackifier such as rosin, dammar, polymerized rosin, partially hydrogenated rosin, ester rosin, polyterpene-based adhesive is added to any adhesive such as resin, polyamide-based resin, polychlorinated olefin-based resin, polyvinyl butyral-based resin, etc. Resin, modified terpene, petroleum resin, ncropentadiene resin, phenolic resin,
Examples include those in which appropriate amounts of styrene resin, xylene resin, coumaron indene resin, etc. are added, and if necessary, softeners, fillers, anti-aging agents, etc. can also be added.

The base material 2 may be any material that can be used as a base material for adhesive notebooks, such as metal foils such as aluminum, copper, and iron, polyethylene terephthalate, polybutylene terephthalate, and polyethylene terephthalate/isophthalate copolymers. Polyester resins, polyolefin resins such as polyethylene, polypropylene, and polymethylpentene; polyfluorinated ethylene resins such as polyvinyl fluoride;
, polyamides such as nylon 6.6, polyvinyl chloride, vinyl chloride/vinyl acetate copolymers, ethylene/vinyl acetate copolymers, ethylene/vinyl alcohol copolymers, polyvinyl alcohol, vinyl polymers such as vinylon, triacetic acid Cellulose resins such as cellulose and cellophane, acrylic resins such as polymethyl methacrylate, polyethyl methacrylate, polyethyl acrylate, and polybutyl acrylate, synthetic resin films such as polystyrene, polycarbonate, polyarylate, polyimide, etc. A single layer or a laminate of multiple sheets, or paper such as high-quality paper, thin paper, glassine paper, parchment paper, cloth, nonwoven fabric, etc. made of one or more types of glass fiber, natural fiber, synthetic fiber, etc. Can be mentioned.

The thickness of the base material 2 is not particularly limited, but is usually 12 to 200 mm.
A diameter of approximately μm is used. In addition, the base material 2 and the adhesive layer 3
If necessary, the surface of the base material 2 may be subjected to known adhesion-facilitating treatments such as corona discharge treatment, plasma treatment, brimer coating, degreasing treatment, and surface roughening treatment.

The adhesive notebook of the present invention can be treated to impart writing characteristics depending on its use. For example, as shown in FIG. 2, if the surface of the base material 2 opposite to the surface on which the adhesive layer is formed is the writing surface 6, the surface of the writing surface 6 is treated by a known method to form the writing portion 7. You may.

Methods for forming the writing portion 7 include, for example, applying a resin containing microparticles, creating a base material containing microparticles, and roughening the surface of the base material by a known method such as sandblasting. Examples of methods include:

Further, if necessary, a decorative layer 8 consisting of a pattern, a thin metal film, etc. can be provided on one or both sides of the base material 2, either entirely or partially, by a method such as printing or vapor deposition.

As shown in FIG. 2, in the adhesive sheet l of the present invention, since the adhesive convex body 5 is integrated with the adhesive base layer 4, the base material 2
As a result, when the pressure-sensitive adhesive sheet of the present invention is pasted on the adherend 9 and then peeled off, the convex body 5 detaches from the base material 2 and the adhesion is reduced. Good peeling can be carried out without the risk of the particles remaining on the surface of the body 9.

Next, the method for manufacturing the pressure-sensitive adhesive sheet of the present invention will be explained.

As shown in FIG. 3(a), a release film 11 having a large number of recesses 10 is prepared, and an adhesive is applied to the surface of the release film in the recesses 10 as shown in FIG. 3(b). Apply the coating thicker than the depth. That is, the adhesive is applied so as to completely fill the recess 10 and to form a continuous adhesive layer of a predetermined thickness thereon. Next, as shown in FIG. 3C, a base material 2 is bonded to the surface of the adhesive layer 3 to obtain a removable adhesive sheet 1.

In the above process, the adhesive filled in the recess 10 forms the adhesive convex body 5, and the adhesive continuously coated thereon to a predetermined thickness forms the adhesive base layer 4.

The shape of the recess 10 of the release film 11 may correspond to the shape of the adhesive convex body 5, and the method of forming the recess 10 on the release film 11 is the conventionally known heat pressure method. Examples include embossing.

The material of the release film 11 is not particularly limited as long as the adhesive force between the release film 11 and the adhesive layer 3 is smaller than the adhesive force between the base material 2 and the adhesive layer 3.

Materials for the release film include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene terephthalate/isophthalate copolymers, polyolefin resins such as polyethylene, polypropylene, and polymethylpentene, polyvinyl fluoride, polyvinylidene fluoride, and poly-47. ethylene chloride, ethylene-
Polyfluorinated ethylene resins such as 47 modified tyrene copolymers, polyamides such as nylon 6 and nylon 6.6, polyvinyl chloride, vinyl chloride/vinyl acetate copolymers, ethylene/vinyl acetate copolymers, ethylene/vinyl Alcohol copolymers, polyvinyl alcohol, vinyl polymers such as vinylon, cellulose resins such as cellulose triacetate and cellophane, acrylics such as polymethyl methacrylate, polyethyl methacrylate, polyethyl acrylate, and polybutyl acrylate. Examples include monolayers of synthetic resin films or sheets such as polystyrene, polycarbonate, polyarylate, and polyimide, or laminates of a plurality of them, and papers such as high-quality paper, thin paper, granone paper, and parchment paper.

Further, in order to facilitate the release of the release film 11 and the adhesive layer 3, a release treatment can be performed.

The mold release treatment may be performed before the recesses 10 are provided in the release film 11, or after the recesses 10 are provided.

For mold release treatment, for example, waxes such as fluorine resin, paraffin wax, Monkwanox, and base wax, and mold release agents such as Noricone are used with known vehicles such as acrylic resin, cellulose resin, vinyl resin, etc. A paint film containing the above paint is applied to the surface of the release film, and a release resin such as fluorine-based resin, silicone, polysiloxane, melamine-based resin, urethane-based resin, polyolefin is used. resin,! #Coat a radiation-crosslinkable multifunctional resin such as acrylate, polyester, epoxy, titanium chelate, or polyimine on the surface of the release film to form a film of the resin, or release the above resin by extrusion coating, etc. Laminate on the mold film,
A method of forming a release layer on a release film to a thickness of about 0.1 to 1 μm may be mentioned.

The method of applying the adhesive to the release film 11 is not particularly limited, and the adhesive layer can be formed by, for example, a conventional coating method such as roll coating, die-coach ink, Clavia coating, or comma coating. Among these, post-weighing methods such as comma coating are preferred because they provide superior smoothness of the coated surface.

The pressure-sensitive adhesive sheet of the present invention can be produced in either a single sheet or a continuous roll.

When manufacturing adhesive sheets in a continuous roll, there are two methods: applying the adhesive material to a release film, bonding the base materials together, and then winding it up into a roll without peeling off the release film, or applying the adhesive to the back side of the base material. Either method may be used, in which a release treatment is performed on the adhesive sheet using known materials and methods, the release film is peeled off, and the pressure-sensitive adhesive sheet is wound up into a roll.

The pressure-sensitive adhesive sheet, which is wound up into a roll after peeling off the release film, can save the effort of peeling off the release film during use.

(Function) Since the adhesive sheet 1 of the present invention has a large number of adhesive convex bodies 5 on the adhesive layer 3, when it is attached to an adherend 9, the contact area between the adhesive layer 3 and the adherend is becomes smaller, and adhesive sheet 1
The adhesive strength of the adhesive is appropriately reduced, and the adhesive can be easily peeled off from the adherend 9.

Further, by providing the adhesive convex body 5 so as to protrude outward from the surface of the adhesive base layer 4, it is possible to temporarily attach only the adhesive convex body 5 to the adherend 9 by lightly pressing the adhesive sheet. Main adhesion can be achieved by adhering and pressing even more strongly to adhere up to the adhesive base layer 4 to the adherend.

Furthermore, since the adhesive convex body 5 and the adhesive base layer 4 are integrally formed to form the adhesive layer 3, the adhesive convex body 5 is firmly attached to the base material 2 via the adhesive base layer 4. It is fixedly held, and when the adhesive sheet is peeled off from the adherend 9, the adhesive convex body 5 does not come off and remain on the adherend 9 side.

[Example] Hereinafter, the present invention will be explained in more detail by giving specific examples.

Example 1 On the surface of a release film made of polypropylene on which many hemispherical recesses with a radius of 25 μm were formed by embossing, the hemispherical recesses were filled with an acrylic bifurcated adhesive with a viscosity of 3000 cps, and then the film was After applying the adhesive to a thickness of 10 μm from the flat surface, apply the adhesive at 120°C.
The adhesive layer was formed by drying for a minute. Then, the thickness is 38μ
A pressure-sensitive adhesive sheet was obtained by laminating a film made of polyethylene terephthalate (m) on the surface of the above-mentioned pressure-sensitive adhesive layer using a goblin.

When the release film of the resulting pressure-sensitive adhesive sheet was peeled off and re-peelability was tested, it was found that the adhesive sheet could be peeled off well without any adhesive remaining on the surface of the adherend.

(Effects of the Invention) As explained above, the pressure-sensitive adhesive sheet of the present invention has a large number of pressure-sensitive adhesive convex bodies integrally formed with the pressure-sensitive adhesive base layer so as to protrude outward from the pressure-sensitive adhesive base layer. Since the shaped body is firmly fixed and held on the base material through the adhesive base layer, when the adhesive sheet is peeled off from the adherend, no adhesive remains on the adherend side compared to conventional adhesive sheets, making it possible to remove the adhesive sheet from the adherend. It is possible to perform a peeling process.

Furthermore, the manufacturing method of the present invention involves coating the surface of a release film with a large number of recesses with an adhesive thicker than the depth of the recesses, and then bonding the base material, compared to conventional methods for manufacturing adhesive sheets. Adhesive sheets that are easy to manufacture and have good peeling properties can be produced with high productivity and stable quality.

According to the manufacturing method of the present invention, by coating the surface of a release film having recesses with an adhesive thicker than the depth of the recesses, the adhesive protrusions protruding outward from the surface of the adhesive base layer are adhered. It can be formed integrally with the adhesive base layer, eliminating the need for a separate process to form the adhesive convex body, resulting in a uniform convex shape, improving productivity and quality stability. .

Furthermore, since a release film with concave portions is used, the shape of the adhesive convex portion can be changed by changing the shape of the release film, allowing for easy release depending on the type of adherend. Characteristics can be easily changed.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing an example of the adhesive sheet of the present invention, and FIG.
The figure is a longitudinal sectional view showing an example of use of the adhesive notebook of the present invention, and Figures 3 (al to C) are explanatory diagrams showing the method of manufacturing the adhesive sort of the present invention. 3... Adhesive layer 4... Adhesive base layer 5... Adhesive convex body
DESCRIPTION OF SYMBOLS 10... Concavity 11... Release film...Adhesive/-T2...Base material 3...Adhesive layer 4...Adhesive base layer 5...Adhesive convex body 2nd figure

Claims (2)

[Claims] (1) A pressure-sensitive adhesive base layer of a predetermined thickness is provided on the surface of the base material, and a number of pressure-sensitive adhesive convex bodies protruding outward from the surface of the pressure-sensitive adhesive base layer are provided integrally with the pressure-sensitive adhesive base layer. Adhesive sheet with removability. (2) Apply adhesive to the surface of a release film having a large number of recesses so that the adhesive is filled in the recesses and a pressure-sensitive adhesive base layer of a predetermined thickness is continuously formed on the recesses. 1. A method for producing a pressure-sensitive adhesive sheet having removability, the method comprising: processing the pressure-sensitive adhesive sheet, and then bonding a base material to the surface of the pressure-sensitive adhesive base layer.