JP2000178514A - Adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To have a specific modulus and a peeling force, to have good workability in an adhesive processing step, and to be suitable for manual peeling or auto labeler, and to be capable of recycling a peeled sheet after use. Provide an adhesive sheet. SOLUTION: In a pressure-sensitive adhesive sheet obtained by laminating a surface substrate, a pressure-sensitive adhesive layer, and a release sheet obtained by applying a release agent to a thermoplastic resin film, the main component of the thermoplastic resin film is polyethylene, polypropylene, polystyrene. The thermoplastic resin film has a secant modulus in the MD direction and the TD direction of the thermoplastic resin film of 3,000 to 30,000 kgf / cm ^2. 1 to 15gf / 25mm, 5m at 300mm / min
A pressure-sensitive adhesive sheet having a thickness of 1 to 35 gf / 25 mm / min.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a pressure-sensitive adhesive sheet, and more particularly, to a pressure-sensitive adhesive sheet using a thermoplastic resin film having a specific modulus and having a specific peeling force. Further, the present invention relates to a pressure-sensitive adhesive sheet which can be easily peeled off by hand or an auto-labeler, and the used release sheet can be recycled (material recycled).

[0002]

2. Description of the Related Art Adhesive sheets are used for a wide range of applications such as commercial, industrial, office and home use as labels, seals, stickers, patches, plus covers and surface protective sheets. This pressure-sensitive adhesive sheet is generally formed by laminating a surface substrate, a pressure-sensitive adhesive, and a release sheet. As the surface substrate, a paper substrate such as high-quality paper, kraft paper, art paper, coated paper, cast coated paper, or a sheet made of a thermoplastic resin film, synthetic paper, metal foil, or the like is used. I have. As the release sheet, a high-density paper such as glassine paper or kraft paper, or a paper obtained by applying a silicone compound or a fluorine compound to a release paper base paper obtained by laminating a film such as clay coating or a polyethylene film on such paper. It is used. As the adhesive, an acrylic adhesive, a natural rubber-based adhesive, a synthetic rubber-based adhesive, and a silicone-based adhesive are used. Although there are cases where the sticking method is manually performed, an automatic labeler is mainly used, and in recent years, an adhesive label corresponding to a particularly high-speed automatic labeler has been required.

[0003] Among the pressure-sensitive adhesive sheets, there are applications in which transparency and design are strongly required and smoothness of the pressure-sensitive adhesive layer is required, and there is a need for measures against curl change due to moisture absorption of a paper base material. The pressure-sensitive adhesive sheet is a type of release sheet that is exclusively laminated with a film such as polyethylene, and furthermore,
A release sheet made of a thermoplastic resin is also often used.

Further, with respect to these paper-based release sheets,
In recent years, a release sheet obtained by applying a release agent such as a silicone compound or a fluorine compound to a film made of a thermoplastic resin such as polypropylene or polyethylene terephthalate (Japanese Patent Laid-Open No.
A release sheet and a laminate (Japanese Patent Laid-Open No. 5-39423) comprising a thermoplastic resin film containing an additive for imparting releasability are also known. That is, among the pressure-sensitive adhesive sheets, those used as labels having a commercial value are the surface base material and the pressure-sensitive adhesive layer, and are peeled off from the release sheet at the time of use. The release sheet from which the label or the like has been peeled off has been landfilled or incinerated as waste having no use. However, landfill disposal requires securing a disposal site, but incineration disposal has the problem of generating carbon dioxide, a substance that causes global warming. There is also a problem of processing cost burden. As described above, from the viewpoints of global environment protection and effective utilization of resources, a pressure-sensitive adhesive sheet capable of recycling (material recycling) a used release sheet is desired in the market.

[0005]

SUMMARY OF THE INVENTION A release sheet made of a thermoplastic resin which does not require disposal of the release sheet, and
An object of the present invention is to obtain an adhesive label having labeling suitability with a high-speed automatic labeler of m / min or more.

[0006]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a pressure-sensitive adhesive sheet is actually produced by using a release sheet having a specific release force on a thermoplastic resin film having a specific modulus. The inventor has found that the release sheet can be easily separated by hand or a high-speed automatic labeler, and that the release sheet after use can be reused (material recycling). Thus, the present invention has been completed.

That is, the constitution of the present invention relates to a pressure-sensitive adhesive sheet obtained by laminating a surface substrate, a pressure-sensitive adhesive layer, and a release sheet obtained by applying a release agent to a thermoplastic resin film. Is one or a combination of two or more selected from polyethylene, polypropylene, and polystyrene, and the secant modulus in the MD direction and the TD direction of the thermoplastic resin film is 3000 to 30000.
kgf / cm ² , and the 180 ° peeling force of the release sheet is 1 to 1 when the peeling speed is 300 mm / min.
The pressure-sensitive adhesive sheet has a range of 5 gf / 25 mm, and a range of 1 to 35 gf / 25 mm at 5 m / min.

The above-mentioned thermoplastic resin film is a pressure-sensitive adhesive sheet which is a non-stretched or uniaxially stretched film.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The surface substrate used in the present invention is not particularly limited, and paper substrates such as high quality paper, kraft paper, art paper, coated paper, cast coated paper and the like, and thermoplastic resins Films, synthetic papers, sheet-like materials such as metal foils and the like are used, and among them, as physical properties suitable for an automatic labeler, those having appropriate stiffness and tensile strength are appropriately used depending on the purpose. .

The thermoplastic resin, which is the main component of the thermoplastic resin film used for the release sheet of the present invention, has dimensional stability and solvent resistance when a solvent type adhesive is transferred and coated.
Further, considering that the thermoplastic resin is easily recycled, one or a combination of two or more of polyethylene, polypropylene and polystyrene is particularly preferably used. Further, it is more preferable that the melting temperature is low in order to regenerate after recovery.

With respect to the release film, the following preferred embodiments are further considered. Usually, a label printing machine is used to manufacture a label, and after the label is printed, an unnecessary portion is removed (blurred up) by punching into a predetermined shape. At this time, it is important to adjust the penetration depth of the punching blade, and it is known that if the penetration blade is too deep, the release sheet is damaged and this causes the release film to break. In the case of a release film containing polypropylene as a main component, in particular, a biaxially-stretched polypropylene film is apt to be cut, so that the structure is non-stretched or uniaxially stretched, and may have a multilayer structure of two or more layers. preferable. The method for producing the thermoplastic resin film used for the release sheet is not particularly limited, and a known production method can be used.

The pressure-sensitive adhesive used in the present invention is appropriately selected from acrylic pressure-sensitive adhesives, natural rubber-based pressure-sensitive adhesives, synthetic rubber-based pressure-sensitive adhesives, and silicone-based pressure-sensitive adhesives according to the purpose of use.
Depending on the drying and curing method, a solvent-based pressure-sensitive adhesive, an emulsion-type pressure-sensitive adhesive, a hot-melt-type pressure-sensitive adhesive, an ultraviolet-curable pressure-sensitive adhesive, and an electron beam-curable pressure-sensitive adhesive can be used as appropriate. The method of applying the adhesive is a reverse roll coater, a slot die coater,
An air knife coater, bar coater, reverse gravure coater, or the like is appropriately used. The amount of the adhesive applied is not particularly limited, but is 5 to 50 g / m ^{2 in} dry weight depending on the application.
It is applied to the extent.

As the release agent used in the present invention, conventionally known release agents such as condensation reaction type, addition reaction type, ultraviolet ray curing type and electron beam curing type silicone and fluorine compounds are used. The coating amount of the release agent is 0.01 to
2.0 g / m ^2, preferably from 0.05 to 1.0 g / m ^2. If the coating amount of the release agent is small, the release layer tends to be uneven, and the release force is not stable. In addition, if the coating amount is large, or the occurrence of blocking, in the recycling of thermoplastic resin,
Repelling may occur when printing or painting.

A known method can be used for the coating method for forming the release agent layer without any restriction, and a method using an ordinary coating device such as a bar coater, a roll coater, or a direct gravure coater is appropriately used.

According to the present invention, the release sheet of the pressure-sensitive adhesive sheet is obtained by applying a release agent to a thermoplastic resin film.
It is characterized in that it is 1 to 15 gf / 25 mm at 00 mm / min and 1 to 35 gf / 25 mm at a peeling speed of 5 m / min. Here, the measurement of the peeling force is based on JIS K68.
The peeling rate of the release sheet is 3
It is a numerical value when peeling at 00 mm / min and 5 m / min.

According to the method for forming the pressure-sensitive adhesive sheet of the present invention, a pressure-sensitive adhesive is applied to the release-treated surface of the release sheet, dried or cured to form a pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer is formed in accordance with a usual production method. It can be finished by sticking it to the adhesive processed surface of the surface substrate. Conversely, a pressure-sensitive adhesive may be applied to the pressure-treated surface of the surface base material, dried or cured to form a pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer and the release-treated surface of the release sheet may be bonded to finish. . When importance is attached to the appearance of an adhesive label or the like, the former coating method is preferred.

[0017]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

Example 1 (1) Preparation of Acrylic Adhesive n-Butyl acrylate was placed in a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer, a dropping funnel and a nitrogen gas inlet.
5 parts, 64 parts of 2-ethylhexyl acrylate, 3 parts of acrylic acid, 0.5 part of 2-hydroxyethyl acrylate and 0.1 part of perbutyl o as a polymerization initiator were dissolved in 100 parts of ethyl acetate, and polymerized at 80 ° C. for 8 hours. Mw60
Ten thousand acrylic copolymer solutions A were obtained. The mixture was diluted with toluene to obtain an acrylic pressure-sensitive adhesive solution having a solid content of 40%. (2) Preparation of adhesive sheet As a release sheet, a secant modulus 73 having a thickness of 60 μm was used.
KS-847H (manufactured by Shin-Etsu Chemical Co., Ltd.) is applied on one side of a non-stretched polypropylene film substrate of 00 kgf / cm ^2.
100 parts, platinum catalyst PL50T (Shin-Etsu Chemical Co., Ltd.)
Of a mixture consisting of 1.0 part by dry weight of 0.2 g /
was coated so as to m ^2, using those dry cured, this release-treated surface, with respect to the above-mentioned adhesive solution to 100 parts by weight of an isocyanate crosslinking agent (Nippon Polyurethane Co. Coronate L-55) The PSA solution after adding 1.3 parts and stirring for 10 minutes was applied so that the thickness after drying became 20 μm, and dried at 80 ° C. for 2 minutes. A PET film having a thickness of 50 μm was laminated on this at a pressure of 4 kg / cm. Then, it was aged at 23 ° C. for 2 days to prepare the pressure-sensitive adhesive sheet of the present invention.

Example 2 A release sheet having a thickness of 95
KS-847H (manufactured by Shin-Etsu Chemical Co., Ltd.) is applied to one side of a non-stretched polypropylene film / polyethylene mixture base material having a μm and a secant modulus of 3700 kgf / cm ^2.
00 parts, platinum catalyst PL50T (manufactured by Shin-Etsu Chemical Co., Ltd.)
1.0 g of a mixture of 0.2 g / m ^{2 by} dry weight
A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1, except that a coated and dried cured product was used.

Example 3 A release sheet having a thickness of 40
μm of SP-OP-PP-40-S (manufactured by Tocelo Co., Ltd.
A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1 except that a biaxially stretched polypropylene-based release sheet was used.

Example 4 An adhesive sheet was prepared in the same manner as in Example 1 except that a 100 μm-thick unstretched polystyrene film was used as a release sheet substrate.

Comparative Example 1 The release agent of the release sheet was
24-312 (Toray Dow Corning Silicone Co., Ltd.)
Pressure-sensitive adhesive sheet according to Example 1, except that the mixture was changed to a mixture consisting of 100 parts) and 1.0 part of platinum catalyst SRX212 (manufactured by Toray Dow Corning Silicone Co., Ltd.).

[Comparative Example 2] KS-847H (Shin-Etsu Chemical Co., Ltd.)
Of a platinum catalyst PL50T (manufactured by Shin-Etsu Chemical Co., Ltd.) in an amount of 0.1 part by dry weight.
A pressure-sensitive adhesive sheet was prepared in accordance with Example 1, except that the composition was applied at ² g / m ² and dried and cured.

[Comparative Example 3] A film obtained by laminating glassine paper on an unstretched polyethylene film was coated with K
A mixture of 100 parts of S-847H (manufactured by Shin-Etsu Chemical Co., Ltd.) and 1.0 part of platinum catalyst PL50T (manufactured by Shin-Etsu Chemical Co., Ltd.) was applied to a dry weight of 0.2 g / m ^2. Example 1 was used except that the processed and dried cured product was used.
To prepare a pressure-sensitive adhesive sheet.

The evaluation method according to the present invention will be described below. <Separation Modulus> A test piece having a width of 25 mm and a line spacing of 100 mm was prepared in accordance with JIS-K7127 tensile modulus of elasticity, and measured in the MD and TD directions of the film.
It was measured at a tensile speed of 0 mm / min. The specified strain (elongation) was 5%.

<Peeling Force> A test piece having a width of 25 mm and a length of 100 mm was fixed to a stainless steel plate having a thickness of 2 mm on the surface substrate side with a double-sided adhesive tape. Release sheet 300m in 180 ° direction
Peeling was performed at a tensile speed of m / min and 5 m / min, and the peel strength was measured.

<Label Attaching Property> The adhesive label prepared in the punching process test was evaluated in a state where the label was caught when 1000 sheets were continuously attached by an automatic labeler. ：: No crawling failure, Δ: Crawling failure 9 or less, ×: Crawling failure 10 or more.

<Recyclability> The workability (melting temperature) of melting and pelletizing with an extruder or the like in order to reuse the peeled film was evaluated. ：: good, △: high melting temperature but pelletizable, ×: unable to pelletize.

<Applicability> The pressure-sensitive adhesive sheets having the constitutions shown in Examples and Comparative Examples were evaluated from workability. ：: good, △: some unevenness occurs, ×: poor (because film shrinkage is large)

<Punching Workability> Adhesive sheets having the constitutions shown in the examples and comparative examples were formed into roll samples having a width of 200 mm. Half-cut processing was performed by a punching machine for 1000 shots, and occurrence of cracks in the release sheet after processing was visually determined. ：: no cracks, Δ: rarely occurred, ×: many cracks occurred.

[0031]

[Table 1]

[0032]

The pressure-sensitive adhesive sheet of the present invention is a thermoplastic resin film having a specific modulus and has a specific release force, so that the workability of the release treatment and the adhesive processing step is good.
Good suitability for manual peeling or high-speed automatic labeler. Further, the release sheet can be recycled (material recycled) after use.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Go Iwasaki 3-213 Mansion Fujimaru 201 3-213 Chuo, Komaki-shi, Aichi (72) Inventor Akihiro Yamada 3-226 Chuo 3-226 Chuo, Komaki-shi, Aichi 501 (72) Inventor Kozo Akasaka 1350-2, Kuraya, Omagari, Maizuru-shi, Kyoto Inside the Maizuru Plant of Osaka Shiseido Co., Ltd. (72) Inventor Hiroshi Sawa 3-2-16 Kamioshi, Tennoji-ku, Osaka-shi, Osaka F-term (reference) 4J004 AA03 AB01 CA02 CB02 CB03 DB03

Claims (2)

[Claims] 1. A pressure-sensitive adhesive sheet obtained by laminating a release sheet obtained by applying a release agent to a surface substrate, a pressure-sensitive adhesive layer, and a thermoplastic resin film, wherein the main component of the thermoplastic resin film is polyethylene, polypropylene, One or a combination of two or more selected from polystyrene,
The secant modulus in the MD and TD directions of the thermoplastic resin film is 3000 to 30000 kgf / cm ^2.
At 00 mm / min, 1 to 15 gf / 25 mm, 5 m /
a pressure-sensitive adhesive sheet having a thickness of 1 to 35 gf / 25 mm in min. 2. The pressure-sensitive adhesive sheet according to claim 1, wherein the thermoplastic resin film is a non-stretched or uniaxially stretched film.