JPH11124797A - Release sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a release sheet to be used in a state laminated to a tacky adhesive face of a tacky adhesive label, etc., exhibiting good peeling force and excellent air entrapping preventing performance and usable in an automatic pasting unit for label, etc., without trouble. SOLUTION: This release sheet has a release layer on at least one surface of a substrate. The maximum height of the protrusions on the surface of the release layer is 10-40 nm and the number of protrusions per unit area is 5-20 CN/0.1 mm<2> measured by a three-dimensional surface roughness tester.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a release sheet used in an adhesive processed product such as a wallpaper, a sticker, a sticker or the like to be adhered to an adhesive surface.

[0002]

2. Description of the Related Art In recent years, as the demand for adhesive processed products such as seals and stickers has increased, the demand for a release sheet to be bonded to the adhesive surface of these adhesive processed products has also increased, and the quality requirements thereof have become stricter. ing. Conventionally, as this kind of release sheet, a release layer formed by applying a release agent such as a releasable silicone resin to one or both sides of paper serving as a support, for example, glassine paper, is generally used. One of the applications of these release papers is to impart opacity, particularly to an adhesive processed product made of a transparent support, by roughening the release surface and providing fine irregularities on the adhesive surface of the adhesive processed product. ing.

Conventionally, as this kind of release paper having a roughened release surface, a paper obtained by laminating a thermoplastic resin such as polyethylene on a paper as a support and roughening the resin surface is used. It is common. That is, when laminating a thermoplastic resin on paper, after manufacturing a support having a roughened surface by combining with a matte roughened roll before the resin cools and solidifies,
A release paper is obtained by providing a release layer on the surface. However, on the surface of the roll, only irregularities such as matting are formed, so that the irregularities on the surface of the support obtained by transferring the same are at most several μm. Was. Therefore, the pressure-sensitive adhesive processed by using such a conventional roughened release paper, not only can not obtain sufficient opacity, but also air entrapment due to poor air permeability, That is, at present, there is a problem of so-called swelling in which air remains between the adhesive layer and the release paper during the adhesive processing.

[0004] Further, it has also been practiced to automatically affix these adhesively processed labels to an object using an automatic affixing unit incorporated in a production line. Also in this case, since the automatic labeling unit attaches the adhesive label and the release paper while separating them, there is a problem of air entrapment that air enters between the adhesive label and the adherend. The problem of such air entrapment is that even when the adhesive processed product is bonded by hand, there is also a problem that air is entrapped between the adhesive layer and the adherend to form swelling. However, there is a strong demand for an adhesive-processed product which is poor in appearance when air is entrained and which prevents air entrapment.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a release sheet having a roughened surface having moderate irregularities on the surface of a release layer. The present invention relates to a release sheet in which air entrapment of a processed product is prevented.

[0006]

According to the present invention, there is provided a release sheet comprising a support and a release layer provided on at least one surface of the support.
The maximum height of the surface of the release layer measured by a three-dimensional surface roughness meter is 1
0 to 40 μm, the number of peaks per standard area is 5 to 20 CN / 0.
1 mm ² is a release sheet.

In the release sheet of the present invention, by forming the surface of the release layer so as to have a surface having the above-mentioned specific unevenness, a good and stable release force is achieved, and air entrapment is achieved. Can be prevented. The maximum height (SRma) measured by the three-dimensional surface roughness meter according to the present invention is the maximum height of the projections on the surface, that is, the lowest part (the part where the thickness of the release layer is the thinnest) as viewed in the thickness direction of the release layer. It represents the difference between the highest part (the part where the thickness of the release layer is the thickest), and the number of peaks per standard area (SPC) is the number of protrusions per unit area (height 1 μm).
m or more). Such S
Rma and SPC are measured by a three-dimensional roughness measuring instrument using a stylus method, and examples of such measuring instruments include Model SPA-11 manufactured by Kosaka Laboratories.

In the present invention, the SRma measured as described above is 10 to 40 μm, preferably 20 to 30 μm.
m, and the SPC needs to be 5 to 20 CN / 0.1 mm ² , preferably 7 to 17 CN / 0.1 mm ² . If any of SRma and SPC is less than the above range, the release layer does not have sufficient surface roughness,
Therefore, sufficient opacity and the property of preventing air entrapment cannot be imparted to the adhesive surface of the adhesive processed product. Conversely, if it is larger than this range, air will remain between the release layer and the adhesive layer when laminating the adhesive processed product, or there will be a problem that the adhesive processed product itself will have irregularities. I will.

The release layer in the present invention is formed by appropriately using a commonly used release agent such as a silicone-based or fluorine-based release agent, and its composition is not particularly limited. In order to form the specific irregularities as described above on the surface of such a release layer, for example, a substrate in which appropriate irregularities are formed in advance is used. A method such as providing an undercoat layer, processing the surface of the release layer to form irregularities, or adding a pigment or the like to the release layer within a range that does not impair the releasability to form the irregularities can be appropriately used. In the present invention, among these methods, a method of providing an undercoat layer is particularly preferable because a desired uneven shape can be easily formed at low cost and there is no fear of impairing the properties of the release agent. .

In the present invention, the undercoat layer provided between the support and the release layer is provided in order to express the above-mentioned specific unevenness on the surface of the release layer as described above. Although the composition is not particularly limited, since any irregular shape can be easily formed,
It is preferable to use resin and fine particles as main components.

In the present invention, as a resin used for the undercoat layer, a commonly used material for forming a film can be appropriately selected and used. Specific examples of the resin include an acrylic resin, a styrene-acryl copolymer resin, a styrene-butadiene copolymer resin, a vinyl acetate resin, an ethylene-vinyl acetate copolymer resin, and a vinyl chloride-vinyl acetate copolymer resin. , Polyvinyl alcohol resin, polyvinyl butyral resin, polyvinyl acetal resin, casein, starch, oxidized starch, acetyl cellulose, nitrocellulose, ethyl cellulose,
Methylcellulose, carboxymethylcellulose, polyvinylpyrrolidone, polyurethane-based resin, polyester-based resin, epoxy-based resin, silicone-based resin, and the like, or a mixture of two or more of these, or copolymerizable in the form of a graft or block Examples thereof include those obtained by copolymerizing a monomer or reacting with a compound having a functional group to modify the monomer. The form of these materials is not particularly limited, such as an organic solvent solution, an aqueous solution, or an aqueous emulsion, and may be determined in consideration of the dispersibility of fine particles, suitability for paint, compatibility of other materials, and the like.

In the present invention, as the fine particles used for the undercoat layer, those composed of conventionally known inorganic and organic materials which can be dispersed without being dissolved in a resin can be appropriately used. Not limited. Specific examples of the fine particles include silica, calcium carbonate, titanium dioxide,
Diatomaceous earth, talc, calcined clay, inorganic powder such as barium sulfate, starch, acrylic resin, cross-linked polyester resin,
Acrylic-styrene copolymer, benzoguanamine resin,
Urea resin, nylon resin, epoxy resin, phenol resin, resin fine powder such as silicone resin and the like,
Without being limited to these, a resin having good dispersibility in the above-described resin may be appropriately selected.

The undercoat layer according to the present invention comprises the above-mentioned resin and fine particles as main components, and is formed, if necessary, using additives such as a resin curing agent and a dispersant.
Such an undercoating layer is used to form specific irregularities on the surface of the release layer, so that the adhesiveness between the support and the release layer, the matching property between the resin and the fine particles (for example, the adhesive property, the dispersibility of the fine particles, etc.), the fine particle The coating may be formed by applying and drying a coating material adjusted in consideration of conditions such as the particle size, the mixing ratio of the fine particles and the resin, and the amount of coating on the support. In the present invention, among the above conditions, the volume average particle diameter by the Coulter counter method is particularly 1
Fine particles having a particle size of about 25 to 25 μm, preferably 3 to 15 μm, are added to 10 to 100 parts by weight, preferably
When used in a mixing ratio of 0 to 50 parts by weight, an undercoat layer having a uniform and specific uneven shape having particularly good adhesiveness and a barrier effect against a release agent is preferably formed.

The support used in the present invention includes, for example, polyesters such as polyethylene terephthalate, various acrylic and methacrylic polymers, polystyrene, polyvinyl chloride, polycarbonate, polyimide, cellulose acetate (acetate), regenerated cellulose ( (Cellophane), plastic films such as celluloid, paper, synthetic paper, and the like, but are not limited thereto. When a material such as paper, which easily penetrates the coating material, is used as the support, it is preferable to provide a sealing layer for preventing the undercoat layer or the release layer from penetrating. The filling layer can be formed by appropriately selecting various resins that can be used for the undercoat layer.

The release sheet of the present invention has the above-mentioned constitution, and the method of forming the undercoat layer and the release layer is not particularly limited. For example, blade coating, air knife coating, bar coating,
It can be formed by various coating methods such as reverse roll coating and gravure roll coating. In addition, the thickness of each layer or the amount of the dried coating can be appropriately set according to the application, but as a support, 50 to 200 μm
Degree, the undercoat layer is 10 to 40 g / m ^2, preferably 15 to
30 g / m ^2, the release layer is about 0.5 to 5 g / m ^2.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to embodiments. All parts in the examples are parts by weight. Example 1 A high-quality paper having a basis weight of 90 g / m ² was used as a support, and a sealing layer having the following composition was applied on both sides of the support and dried to provide a sealing layer having a dry coating amount of 15 g / m ^2. Was. <Coating for filling layer> Clay 100 parts SBR emulsion (manufactured by Dainippon Ink & Chemicals, Inc., trade name "Luck Star DS-405" solid content 45%) 110 parts Waterproofing agent (manufactured by Sumitomo Chemical Co., Ltd., trade name " Sumirezu Resin SR-613 "Solid content 80%) 3 parts Water 400 parts

Next, a coating for an undercoat layer having the following composition was applied to one surface and dried to provide an undercoat layer having a dry coating amount of 15 g / m ² . <Coating for undercoat layer> 40 parts of polyester resin (manufactured by Toyobo Co., Ltd., trade name "Byron 20SS") 40 parts zinc oxide fine powder (manufactured by Hakusui Chemical Co., Ltd., trade name "Zinhua F", volume average particle by Coulter counter method) Diameter 8 μm) 60 parts Isocyanate curing agent (manufactured by Nippon Polyurethane Co., Ltd., trade name “Coronate L”, solid content 75%) 15 parts Ethyl acetate 40 parts Toluene 20 parts

Next, a release layer paint having the following composition was applied on the undercoat layer and dried, and a release layer having a dry coating amount of 1.0 g / m ² was provided to prepare a release sheet of the present invention. <Coating for release layer> 100 parts of release silicone (Toray Dow Corning Silicone, trade name "SD 7226", solid content 30%) 100 parts Curing catalyst (Tore Dow Corning Silicone, trade name "SRX212") 0.6 part Ethyl acetate 50 parts Toluene 50 parts

Example 2 A release sheet of the present invention was produced in exactly the same manner as in Example 1 except that the coating composition for the undercoat layer was as follows. Polyurethane resin (manufactured by Nippon Polyurethane Co., Ltd., trade name "Nipporan 2304" solid content 35%) 95 parts Silicone resin fine powder (manufactured by Toshiba Silicone Co., Ltd., trade name "Tospearl 3120", volume average particle diameter 12 μm by Coulter counter method) 100 Parts Toluene 120 parts Methyl ethyl ketone 120 parts

Example 3 A 75 μm thick polyester film (I) was used as a support.
A release sheet of the present invention was produced in exactly the same manner as in Example 1 except that Melinex 542) manufactured by CI Japan Ltd. was not used and a sealing layer was not provided. Example 4 A 75 μm thick polyester film (I
A release sheet of the present invention was produced in exactly the same manner as in Example 2 except that Melinex 542) manufactured by CI Japan Inc. was not used and a sealing layer was not provided.

Comparative Example 1 A release sheet for comparison was prepared in exactly the same manner as in Example 1 except that the coating composition for the undercoat layer was as follows. <Coating for undercoat layer> Polyester resin (manufactured by Toyobo Co., Ltd., trade name "Byron 20SS") 40 parts Silicone resin fine powder (manufactured by Toshiba Silicone Co., Ltd., trade name "Tospearl 120", volume average particle size by Coulter counter method) About 2μm) 60 parts Ethyl acetate 40 parts Toluene 20 parts

Comparative Example 2 A comparative release sheet was prepared in exactly the same manner as in Example 4 except that the undercoat layer was not provided and the coating for the release layer was applied directly on the film and dried. Comparative Example 3 After using a high-quality paper having a basis weight of 110 g / m ² as a support, a polyethylene laminate layer (each having a thickness of 30 μm) having a surface roughened by a 120-mesh mat roll was formed on both surfaces thereof. A release sheet for comparison was prepared by providing the same release layer as in Example 1 on one of the polyethylene laminate layers. Comparative Example 4 A high-quality paper having a basis weight of 110 g / m ² was used as a support, and polyethylene laminate layers (each having a thickness of 30 μm) were formed on both surfaces thereof.
After embossing the surface of one of the polyethylene laminate layers so as to form irregularities with a depth of 50 μm at intervals of 250 μm vertically and horizontally, a release layer similar to that of Example 1 is provided on the embossed surface. Thus, a release sheet for comparison was prepared.

The following evaluations were performed on the release sheets prepared in Examples 1 to 4 and Comparative Examples 1 to 4. (1) Surface roughness: The maximum height (SRma) of the release layer surface and the number of peaks per standard area (SPC) using a stylus method three-dimensional roughness measuring instrument (MODEL SPA-11, manufactured by Kosaka Laboratories).
Was measured.

(2) Air Entrapment: An adhesive processed product was prepared by laminating a release sheet and an adhesive label, and the state of air entrapment between the adhesive label and the release sheet was visually evaluated. Further, when the release sheet was peeled off from the pressure-sensitive adhesive product and the pressure-sensitive adhesive label was bonded to the glass plate, the state of air entrapment between the adhesive label and the glass plate was visually evaluated. In addition,
The evaluation was ○ when there was no problem at all, Δ when slight air entrapment was recognized, and × when considerable air entrapment was observed.

[0025]

[Table 1]

The evaluation results are as shown in Table 1, and all of the release sheets of the present invention obtained good characteristics. On the other hand, all of the release sheets of Comparative Examples had a problem of air entrapment.

Since the release sheet of the present invention has a specific uneven shape on the surface of the release layer, it has good quality without being affected by variations in the quality of the release agent and variations in the formation of the release layer. It has releasability and an excellent air entrainment prevention function. Therefore, it is possible to provide an adhesive processed product having excellent appearance and performance without air entrapment, and to achieve excellent productivity without any problem when supplied to an automatic application unit.

Claims (3)

[Claims] 1. A release sheet having a release layer provided on at least one surface of a support, wherein the maximum height of the surface of the release layer measured by a three-dimensional surface roughness meter is 10 to 40 μm, and the number of peaks per standard area is 5 to 5 μm. A release sheet characterized by ²⁰ CN / 0.1 mm ² . 2. The release sheet according to claim 1, wherein an undercoat layer containing resin and fine particles as main components is provided between the support and the release layer. 3. The average particle diameter of the fine particles used in the undercoat layer is 3 to 15 μm, and the mixing ratio (weight ratio) of the resin and the fine particles in the undercoat layer is as follows: resin: fine particles =
The release sheet according to claim 2, wherein the ratio is from 1: 1 to 1:10.