JPH0139699Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field]

The present invention relates to a release paper used for adhesive sheets, adhesive tapes, adhesive sheets, adhesive tapes, synthetic resin film castings, and the like.

[Conventional technology]

A well-known type of release paper that has been widely used in the past is one in which aluminum foil is laminated on one or both sides of the paper, and a release agent layer such as silicone is provided on the aluminum foil. However, when the above-mentioned release paper is used to produce adhesive sheets, adhesive tapes, adhesive sheets and adhesive tapes, or when synthetic resin films are produced by casting, the following problems tend to occur.
That is, a coating machine or a laminating machine is used to form the tape, sheet, or film mentioned above. In this case, the release paper is often placed under high tension and unwound, coated with adhesive or resin, passed over many rolls or plates, dried, and wound up. At this time, the release paper and the roll or plate come into contact, and a high shear force is often applied between them. When a high shear force is applied, the surface of conventional release paper is easily damaged and the release performance is damaged.
Of course, if the mold is damaged, some of the mold release agent and aluminum foil have been removed, so the original mold release performance is significantly reduced. Particularly if the rolls or plates of the coating machine or laminating machine are heated or not driven, the release paper will be extremely damaged and the release performance will be lost. It becomes difficult to obtain products such as sheets and tapes.

[Problem that the invention attempts to solve]

The inventors of the present invention conducted various studies to improve the above-mentioned problems of conventional release paper, such as ease of scratching and lack of scratch resistance. By changing the structure consisting of foil/mold release agent to paper/adhesive/aluminum foil/amino resin or resin/mold release agent whose main components are amino resin and acrylic resin, the above problems can be solved. We found a solution and came up with this invention.

[Means to solve the problem]

That is, in the present invention, aluminum foil is laminated on one or both sides of a release paper base, and on at least one side of the aluminum foil, a resin whose main component is an amino resin alone or a mixture of an amino resin and an acrylic resin is applied. This is a release paper in which a layer A is provided and a release agent layer B is provided on at least one surface of the resin layer A, and has scratch resistance that has not existed in the past. The present invention will be explained in more detail below using the drawings. FIGS. 1 to 2 are sectional views of typical release paper of the present invention, and FIGS. 3 to 5 show modifications of FIG. 1 using the present invention. In the figure, 1 is a release paper base material, 2 is an adhesive layer, 3 is an aluminum foil, 4 is a resin layer whose main components are an amino resin or an amino resin and an acrylic resin, 5 is a release agent layer, and 6 7 indicates a sealant layer other than aluminum foil, and 7 indicates a back resin layer. As the resin layer 4 in the present invention, a resin whose main component is an amino resin or a mixture of an amino resin and an acrylic resin is used. Note that good scratch resistance cannot be obtained using acrylic resin alone. Further, as the amino resin in the present invention, a urea resin and/or a copolymer thereof is used.
Butylated urea is a typical example. Next, as the acrylic resin in this invention,
Polyacrylic esters, polymethacrylic esters and/or copolymers thereof are used. Representative examples include resins synthesized from butyl acrylate, 2-hydroxyethyl acrylate, and methacrylic acid. Note that the blending ratio of the acrylic resin is preferably 0 to 85 wt%. Note that the thickness of the resin layer whose main component is an amino resin or a mixture of an amino resin and an acrylic resin is preferably 0.5 μm or more. The paper used in the present invention includes those commonly used in the past, such as wood-free paper, kraft paper, glassine paper, paper mixed with inorganic fibers, paper mixed with plastic,
Examples include nonwoven fabrics. As the adhesive between aluminum foil and paper, Urthane-based, vinyl acetate-based, EVA-based, epoxy-based, polyolefin-based, polyester/isocyanate-based adhesives, etc. can be used. Further, as the aluminum foil in the present invention, both soft aluminum foil and hard aluminum foil can be used, but hard aluminum foil is more preferable. The mold release agent in the present invention includes silicone resins, such as thermal crosslinking type, UV crosslinking type, or EB crosslinking type silicone, which are conventionally used as mold release agents.
Silicone/polyvinyl alcohol mixture, silicone/cellulose derivative mixture, silicone/polyvinyl alcohol mixture, silicone/cellulose derivative mixture,
Alkyd copolymers, silicone/acrylic copolymers, etc. can be used. To obtain the release paper of the present invention, first, aluminum foil is attached to the paper using an adhesive. Next, a solution of a resin whose main component is an amino resin or a mixture of an amino resin and an acrylic resin is applied, and dried and heat cured using a dryer or the like. Note that it is effective to add a catalyst to this resin solution because it speeds up the thermosetting reaction. Phosphoric acid-based catalysts are well known. Next, a release agent is applied and cured on the resin layer to obtain a release paper. In addition, amino resin,
Alternatively, in order to further strengthen the adhesion with the mold release agent on the surface of the resin layer mainly composed of a mixture of amino resin and acrylic resin, adhesion enhancement treatments such as corona discharge treatment, UV radiation treatment, and adhesion may be applied. A reinforcing agent coating may also be applied. Furthermore, in the release paper of the present invention, as shown in Fig. 1, an adhesive layer/aluminum foil/a resin layer mainly composed of amino resin or amino resin and acrylic resin/a release agent layer are provided on one side of the paper. It may be provided on both sides of the paper as shown in FIG. Also the third
As shown in Figure 4, the above layer is provided on one side of the paper, and on the other side is an adhesive layer/aluminum foil/mold release agent layer or a filler layer other than aluminum foil, such as polyolefin resin, polyvinyl alcohol. , starch, SBR and/
Alternatively, a clay layer/mold release agent layer may be provided. Further, as shown in Fig. 5, the mold release agent layer/resin layer containing amino resin or amino resin and acrylic resin as main components/aluminum foil/adhesive layer/paper/back resin layer. Good too. The back resin is polyvinylidene chloride, polystyrene, styrene, etc.
Examples include butadiene copolymers, cellulose derivatives, and polyolefin resins.

【Example】

Next, the present invention will be explained in more detail with reference to examples. Example 1 Aluminum foil with a thickness of 7 μm was pasted on both sides of a high-quality paper with a basis weight of 80 g/m ² , and then a butylated urea melamine resin toluene solution (containing a phosphoric acid catalyst) was applied to both sides of the aluminum foil and heated at 150°C. They were heated and cured for 30 seconds to a thickness of 3 μm each. Further, silicone for release paper was coated on both sides of the resin layer and cured with heat to form a release agent layer, thereby producing a release paper as shown in FIG. This release paper was passed over a heating plate at 130°C in a coating machine for producing adhesive sheets, and a test was conducted by bringing the release surface into contact with the plate surface and applying shear. the result,
No scratches were observed on the mold release surface, indicating good scratch resistance. Furthermore, the mold release performance was also good. Comparative Example 1 In a test under the same conditions as in Example 1 using the release paper of Example 1 except for the butylated urea resin layer, the release surface was significantly damaged and the release property was also significantly reduced. Finished. Example 2 In place of the butylated urea resin layer of Example 1, a layer of a mixture of butylated urea/polyacrylic acid ester = 5/5 was provided, and a release paper was prepared in the same manner. As a result of examining the scratch resistance of this product, Example 1
It was also extremely good.

[Brief explanation of the drawing]

1 and 2 are cross-sectional configuration diagrams of a typical release paper of the present invention, and FIGS. 3 to 5 show modifications of FIG. 1 using the present invention. FIG. 1 is an enlarged cross-sectional view for explaining the case where a resin layer consisting mainly of adhesive layer/aluminum foil/amino resin or amino resin and acrylic resin is provided on one side of a release paper substrate. Figure 2 also shows the case where they are provided on both sides. Figure 3 shows a case where the resin layer shown in Figure 1 is provided on one side of the release paper base, and an adhesive layer, aluminum foil and silicone release agent layer are provided on the opposite side. FIG. 4 is a cross-sectional view when a filler layer 6 is provided instead of the adhesive layer and aluminum foil in FIG. 3; FIG. 5 is a cross-sectional view when the back resin layer 7 is provided on the opposite side of FIGS. 3 and 4. FIG. 1...Release paper base material, 2...Adhesive layer, 3...Aluminum foil, 4...Resin layer containing amino resin or amino resin and acrylic resin as main components, 5...
...Release agent layer, 6...Sealing agent layer other than aluminum foil, 7
...Back resin layer.

Claims (1)

[Claims for Utility Model Registration] 1. Aluminum foil is laminated on one or both sides of a release paper base, and at least one side of the aluminum foil is coated with an amino resin alone or a mixture of an amino resin and an acrylic resin. A release paper in which a resin layer A mainly composed of is disposed, and a release agent layer B is provided on at least one surface of the resin layer A. 2. The release paper according to claim 1, wherein the amino resin is a urea resin. 3. The release paper according to claim 1, wherein the amino resin is a copolymer of urea resin. 4. The release paper according to claim 1, wherein the amino resin is a mixture of a urea resin and its copolymer. 5. The release paper according to claim 1, wherein the release agent is a silicone resin.