JPH04123231U - adhesive tape - Google Patents

Abstract

(57) [Summary] (with modifications) [Purpose] To provide an adhesive tape that has an embossed pattern and is imparted with releasability, straight-line cutting ability, clear cutting ability, or hand-cutting ability. [Structure] An adhesive layer is provided on one side of a polyethylene stretched film whose degree of crosslinking decreases inward in the thickness direction of the film, or on one side of the laminate of a composite of the film and a laminate that can be cut by hand. and the film surface not having the adhesive layer is formed into an uneven surface consisting of at least an embossed pattern.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

The present invention relates to an adhesive tape, and in particular, it has an embossed pattern, has straight cutability and This invention relates to a polyethylene adhesive tape with good clear cut properties.

0002

[Conventional technology]

Traditionally, adhesive tapes have been required to have various performances depending on the field of use, application, etc. Contains various ingredients such as cellophane, polyester, polyolefin, and acrylic resin. A base material for tape has been proposed. Recently, we have been working on improving the cutting performance of dispenser (tape cutter) cutting blades. , polypropylene or polypropylene with methylpentene polymer or petroleum resin. Various tapes have been proposed in which a stretched film of a blended composition is used as a tape base material. (JP-A-59-176375, JP-B-64-995). However, with conventional adhesive tapes, the cutting properties of cutting blades have not been improved. However, the mold releasability is insufficient as it is, and if a mold release agent such as silicone is applied. However, it was necessary to use release paper. It also has straight cutability and clear Cutting performance was also not sufficient. Furthermore, a cutter is required for cutting. Also, the ability to cut by hand was insufficient.

0003

[Problem that the idea aims to solve]

This invention solves the above problems, has an embossed pattern, has good releasability, and has a straight line. Adhesive tape with good cuttability and clear cuttability, as well as hand-tearability. The purpose of this research is to provide a technology that makes it possible to obtain adhesive tapes with Ru. Other objects and novel features of the present invention will be apparent from the description of this specification and drawings. It will be.

0004

[Means to solve the problem] This invention uses polyethylene whose degree of crosslinking decreases toward the inside in the thickness direction of the film. One side of the cross-linked stretched film (hereinafter also referred to as BOPE film), is a composite of the film and a laminate material that can be cut by hand. The surface of the film that has an adhesive layer and does not have an adhesive layer has at least an adhesive layer. The gist of the adhesive tape is that it is formed on an uneven surface consisting of a boss pattern. do.

[0005] The BOPE film used in the present invention is produced by melt-extruding polyethylene of various densities into a sheet-like or tube-like original film, in which the degree of crosslinking decreases toward the inside in the thickness direction. It can be obtained by crosslinking from both sides by electron beam irradiation or the like, and then stretching at least three times in one direction at a temperature below the melting point of polyethylene. The BOPE film 1 has, for example, a density of 0.9357 g/cm ³ or more and a melt index (measured according to JIS K6760, measured at a temperature of 190°C and a load of 2.16 kg, hereinafter referred to as MI) of 0.5 to 20 g/10 minutes. Made of polyethylene. It is preferable to use a structure of crosslinked layer/uncrosslinked layer/crosslinked layer in which the degree of crosslinking (represented by gel fraction) decreases toward the inside in the thickness direction. It is preferable that the crosslinked layer has a gel fraction of 20 to 70 wt%, the uncrosslinked layer has a gel fraction of 0 wt%, and the composition ratio of each layer is uncrosslinked layer:both crosslinked layers=1:0.1 to 10. The above gel fraction is expressed as the percentage of insoluble portion extracted by boiling p-xylene extraction. In addition, the above-mentioned polyethylene has a molecular weight distribution of high load melt index (JIS K7210, measured at a temperature of 190°C and a load of 21.6 kg, hereinafter referred to as HLMI)/MI of 40 to 200, or a high density polyethylene and a linear Low-density polyethylene, a mixture with other polyethylene resins such as low-density polyethylene, and even high-density polyethylene with hydrogenated petroleum resin may be used. In the present invention, the BOPE film preferably has a stretching ratio of 3 times or more in one direction and an area ratio of 9 times or more. Stretching ratio is in one direction (MD direction or TD direction) 1. 0 to 2.0 times, preferably 1.1 to 1.5 times, and 6.0 to 10.0 times in the direction perpendicular to the direction (TD direction to MD direction or MD direction to TD direction). Preferably, when paper, metal foil, cloth, cellophane, or stretched polystyrene film is pasted, it is possible to provide manual tearability in the TD direction without notches or perforations, and it is preferable that the It can be cut easily and has clear cutting properties that prevent hairs from forming on the cut end. It is preferable that the thickness of the BOPE film is usually 10 to 100μ. Some of the methods for producing the BOPE film have been described above, but other methods disclosed in Japanese Patent Application Laid-open Nos. 59-174321, 59-174322, and 61-74819 can also be applied.

[0006] The laminated material that can be cut by hand and is laminated on the BOPE film is By laminating it with a film, the BOPE film can be easily cut by hand. It is. Such laminated materials include fine paper, impregnated paper, coated paper, and kraft paper. paper such as aluminum foil, metal foil such as aluminum foil, cloth foil such as woven fabric, non-woven fabric, and other materials. Examples include Rofan, stretched polystyrene film, and the like. These laminates are required They may be used together depending on the situation. These composites (laminates) include, for example, urethane-based, vinyl acetate-based, acrylic It can be obtained by pasting the two together using various adhesives such as rubber-based and rubber-based adhesives. can.

[0007] In the present invention, an adhesive layer is provided on one side of the BOPE film or its composite. will be established. In the case of a composite, it is preferable to provide an adhesive layer on the surface of the laminate. The adhesive that makes up the adhesive layer may be rubber-based, acrylic-based, silicone-based, etc. Solvent type adhesive, emulsion type, hot melt type, calendar method type, water soluble type, An example is a solvent-free adhesive such as a liquid curing type, and it is possible to add a tackifier to this. Preferably, the tackifier is a rosin-based, turpentine-based, or synthetic petroleum resin-based adhesive. Examples include imparting agents. The adhesive layer is generally acrylic ester It consists of adhesive. Generally, the adhesive is applied so that the adhesive layer has a thickness of about 15 to 30μ. It is true.

[0008] Figures 1 and 2 show the adhesive tape of the present invention and some of its constituent parts, respectively. A cross section is shown. In these figures, 1 is a BOPE film, 2 is a laminated material, and 3 is a BOPE film. , adhesive, 4 is composite, 5 is adhesive layer, 6 is adhesive tape, 10 is BOP These are, for example, irregularities formed in an embossed pattern provided on the E film.

[0009] Next, an example of the method for manufacturing the adhesive tape of the present invention will be explained. Laminate BOPE film 1 or BOPE film 1 and laminate material 2 with adhesive 3 The composite material 4 thus prepared is passed between an extrusion roll and an embossing roll (not shown), as shown in the figure. As shown in FIG. 1(a) and FIG. 2(a), embossed A space pattern (pattern) 10 is provided. The embossed pattern 10 is, for example, a tortoiseshell, circle, triangle, polygon, or diamond. In addition to the general shapes, any shape may be selected depending on the purpose. In this invention, we use a stretched polyethylene film with a special cross-linked structure as described above. Therefore, this type of embossing can be done at room temperature without heating. It is also characterized by being able to move. In the above, the BOPE film 1 provided with the pattern 10 in advance and the laminated material 2 are may be laminated with an adhesive 3 to form a composite 4. Next, the side opposite to the embossed pattern side of the BOPE film 1 or composite is An adhesive is applied to the surface, and the adhesive layer 5 is applied as shown in FIG. 1(b) and FIG. 2(b). form. Furthermore, by embossing, the embossed pattern 10 is formed on both sides of the BOPE film 1. may be accomplished. Generally, in order to improve the release property of adhesive tapes with adhesive layers, A release agent or release paper is applied to the back side where no adhesive is applied, but in this invention, Since the mold releasability is good, there is no need for this. Figure 3 schematically shows this matter. In the figure, when the adhesive tape is unwound, the release property is good and the adhesive layer 5 is attached to the other adhesive tape. - The embossed pattern 10 makes it easy to separate from the BOPE film 1. Can be molded.

0010

【Example】

Next, the present invention will be explained based on Examples and Comparative Examples. The adhesive tapes in Examples and Comparative Examples were evaluated by the following method. Test method 1) Moisture permeability: Compliant with JIS Z0208 (temperature 40°C, relative humidity 90%) 2) Haze: Compliant with JIS K6714 3) Hand tearability: Pinch the MD direction end of the laminated film with the fingertips of both hands, By pulling their fingertips in opposite directions (direction of higher stretching ratio), it was determined whether the samples could be easily torn or not. 4) Cutability: It was checked whether the above-mentioned tearing method could be used to cut in a straight line and whether the cut edge was clear during cutting.

Example 1. Comparative Examples 1-3. A raw sheet formed from high-density polyethylene (density 0.957 g/cm ³ , MI = 1.0 g/10 minutes) and crosslinked with electron beams (gel fraction (%) = crosslinked layer / uncrosslinked layer / crosslinked layer = 50 / 0/50, thickness 500μ) at 127° C. and a magnification of 4×6 to obtain a biaxially stretched film having a thickness of 20μ (hereinafter referred to as BOHD film-1). This film had a haze of 2.7% and a moisture permeability of 3.6 g/m ² /24 hrs. Next, the above-mentioned BOHD film-1 was passed between a press roll and an embossing roll, and embossing was performed at room temperature to give an embossed pattern. An acrylic acid ester adhesive was applied to the non-embossed surface of the obtained embossed film, and a 20 μm thick adhesive tape was wound around only the adhesive layer. The obtained adhesive tape had good mold releasability during unwinding, and could be clearly cut in a straight line from the notched area. For comparison, a polypropylene biaxially stretched film (OPP film, 20μ thickness) and a polyester biaxially stretched film (PET film, 20μ thickness) were coated with adhesive in the same manner as in Example 1, except that no embossing was performed. and rolled up the adhesive tape. The resulting adhesive tape had poor releasability during unwinding, and could not be clear-cut in a straight line from the notched area.

Example 2. An adhesive tape was obtained in the same manner as in Example 1, except that high-quality paper (50 g/m ² ) was laminated on the BOHD film-1 in Example 1 using an EVA emulsion type adhesive by wet lamination. The resulting adhesive tape had good releasability during unwinding, and could be clearly cut in a straight line from the notched area.

Example 3. Comparative example 3. A raw sheet formed from high-density polyethylene (density 0.957 g/cm ³ , MI = 1.0 g/10 minutes) and crosslinked with electron beams (gel fraction (%) = crosslinked layer / uncrosslinked layer / crosslinked layer = 50 / 0/50, thickness 220μ) at 127° C. and a magnification of MD 1.3×TD 7.0 to obtain a biaxially stretched film (hereinafter referred to as BOHD film-2) having a thickness of 25μ. This film had a haze of 2.7% and a moisture permeability of 5.0 g/m ² /24 hrs. Next, the above BOHD film-2 and high-quality paper (50 g/m ² ) were laminated by wet lamination using an EVA emulsion type adhesive to form a laminated film. In addition, the above BOHD film-2 was wet-laminated with aluminum foil (9μ thick), cotton woven cloth (8 g/m ² ), cellophane (300 count), and stretched polystyrene film (12μ thick) using a urethane adhesive. These were laminated to form a laminated film. The surface of the BOHD film-2 of each of the obtained laminated films was embossed at room temperature in the same manner as in Example 1, and then an adhesive layer was formed on the surface of the laminated material, and adhesive tape was applied. I wound it up. The resulting adhesive tape had good release properties during unwinding, was able to be easily cut by hand without having to make a notch, and could be clearly cut in a straight line. For comparison, a laminated film was obtained by extruding and laminating low-density polyethylene to a thickness of 30 μm on the surface of the above-mentioned high-quality paper. An adhesive layer was formed on the obtained laminated film in the same manner as in Example 1, and an adhesive tape was wound up. The resulting adhesive tape had poor releasability during unwinding, was not easy to cut by hand unless notched, and could not be cut straight in a straight line.

[0014]

[Effect of the idea]

As mentioned above, the adhesive tape of the present invention has good releasability during unwinding, so There is no need to apply a release agent or interpose a release paper on the back side where no adhesive is applied. In addition, in order to use a polyethylene stretched film with a special cross-linked structure, we can cut straight lines. Good hardness and clear cutting properties. Furthermore, in embossing, heating Easy processing as embossed patterns can be applied at room temperature without It is economical. In particular, polyethylene cross-linked stretched fibers with a special cross-linked structure and stretched at a specific stretching ratio are Luminous materials can be laminated with paper, metal foil, fabric, cellophane or oriented polystyrene film. By doing so, it can be easily cut by hand without having to make a notch. Furthermore, the cut The straightness and clear cutting properties in cutting are also good.

[Brief explanation of drawings]

FIG. 1 is a partial cross-sectional view of the adhesive tape of the present invention and its constituent parts, (a) is a partial cross-sectional view of the same constituent part, (b)
is a partial cross-sectional view of the same adhesive tape.

FIG. 2 is a partial cross-sectional view of an adhesive tape and its constituent parts showing another embodiment of the present invention, (a) is a partial cross-sectional view of the same constituent part, and (b) is a partial cross-sectional view of the same adhesive tape. - FIG.

FIG. 3 is an explanatory diagram showing the effects of the adhesive tape of the present invention,

[Explanation of symbols]

In these figures, 1 is a BOPE film, 2 is a laminate, 3 is an adhesive, 4 is a composite, 5 is an adhesive layer,
Reference numeral 6 indicates an adhesive tape, and reference numeral 10 indicates a concavo-convex pattern, for example, an embossed pattern provided on the BOPE film.

Claims (3)

[Scope of utility model registration request] Claim 1: An adhesive is applied to one side of a crosslinked stretched polyethylene film in which the degree of crosslinking decreases inward in the thickness direction of the film, or to one side of the laminate of a composite of the film and a laminate that can be cut by hand. An adhesive tape characterized in that the film surface having an adhesive layer and not having the adhesive layer is formed into an uneven surface consisting of at least an embossed pattern. 2. The adhesive tape according to claim 1, wherein the polyethylene crosslinked stretched film has a stretching ratio of 1.0 to 2.0 times in one direction and in a direction perpendicular to this direction.
An adhesive tape characterized by being 0 to 10.0 times larger. Claim 3: The adhesive tape according to claim 1 or claim 2.
An adhesive tape, characterized in that the laminate material having the property of being cut by hand is paper, metal foil, cloth, cellophane, or stretched polystyrene film.