JPH0593173A - Production of pressure-sensitive adhesive tape for surface protection of thin layer - Google Patents

Abstract

PURPOSE:To obtain efficiently the title tape which is excellent in the workability in deep drawing, has a minimum practicable thickness, and is therefore less problematic in the disposal as an industrial waste after being peeled off. CONSTITUTION:The title process comprises sticking a pressure-sensitive adhesive tape for surface protection to at least either surface of a stretchable support and stretching the tape above the melting point of the base of the adhesive.

Description

Detailed Description of the Invention

[0001]

The present invention is excellent in deep drawing workability,
The present invention relates to a method for producing an adhesive tape for surface protection, which has a practically minimum thickness.

[0002]

[Prior Art and Problems to be Solved by the Invention] In general,
The surface protection adhesive tape is made by forming a film of thermoplastic resin such as low density polyethylene by extrusion molding such as T-type die method or inflation method, and then coating a solvent-type or emulsion-type adhesive solution on this film and drying. It is manufactured by However, with this method, a film thickness of 40
If you try to manufacture a thin adhesive tape of less than μm,
The film swells and softens under the influence of the solvent of the pressure-sensitive adhesive solution or the heat during drying, and the film is cut during production or wrinkles or the like are formed, whereby the yield is significantly reduced. For these reasons, the surface-protective pressure-sensitive adhesive tapes for low-density polyethylene substrates currently on the market have a film thickness of more than 40 μm. However, since the film thickness is thick, when used as an adhesive tape for surface protection during deep drawing of stainless steel plate, etc., the adhesive tape peels off from the edges due to the residual stress of the film during the process, and a dent is formed in the next process. It becomes a cause.

As a method for thinning the pressure-sensitive adhesive tape, a method has been devised in which a base film is coated with a pressure-sensitive adhesive and then stretched. However, in the case of an adhesive tape using low-density polyethylene as a base material, the melting point is low and the drawability is poor, so it is not possible to substantially increase the draw ratio, and the orientation during drawing increases the strength in the drawing direction. Since the elongation decreases, the physical properties of the pressure-sensitive adhesive tape are far from the original properties, which is a problem when used as a surface-protection pressure-sensitive adhesive tape particularly for deep drawing.

The object of the present invention is to provide a method for producing a pressure-sensitive adhesive tape for thin layer surface protection, which can be stretched at a high ratio without causing breakage or uneven stretching during stretching and is excellent in deep drawing workability. That is.

[0005]

Means for Solving the Problems The above object is to adhere an adhesive tape for surface protection to one or both sides of a support having stretchability, and to perform stretching at a temperature equal to or higher than the melting point of the base material of the adhesive tape. This can be achieved by a method for producing a pressure-sensitive adhesive tape for protecting a thin layer surface. That is, by laminating a film having good stretchability, such as unstretched polypropylene, and stretching it, it is possible to stretch at a high magnification without causing breakage or uneven stretching during stretching. By stretching at a temperature not lower than the melting point of the base material of the pressure-sensitive adhesive tape for surface protection and lower than the melting point of the supporting film, various problems such as change in strength due to orientation of the base material film during stretching, decrease in elongation, shrinkage during heating, etc. Can be solved.

The base material of the adhesive tape for surface protection is not particularly limited as long as it is a plastic film having flexibility,
For example, a polyolefin resin, a polyester resin, a vinyl chloride resin and the like can be mentioned, and a polyolefin resin is preferable. The polyolefin resin may be a homopolymer, a copolymer, or a blended product thereof, and specifically, α-such as polyethylene and polypropylene.
Examples include olefin homopolymers, ethylene-propylene copolymers, ethylene-vinyl acetate copolymers, ethylene-ethyl acrylate copolymers and other α-olefin and carboxylic acid copolymers, and blends thereof. Among them, low density polyethylene is preferable,
More preferably, linear low density polyethylene. The density of this polyethylene is preferably 0.90 to 0.95.
g / cm ^3, more preferably from 0.92~0.94g / cm ^3. The melting point of the base material is preferably 100 to 140.
C., more preferably 105 to 120.degree. The film thickness of the base material is preferably 40 to 200 μm, more preferably 60 to 100 μm.

As the pressure-sensitive adhesive for the surface-protecting pressure-sensitive adhesive tape, those known in this field may be used, for example, natural rubber-based, acrylic-based, polyisobutylene, styrene-
Examples thereof include butylene-styrene copolymer and styrene-ethylene-butylene-styrene copolymer. The pressure-sensitive adhesive layer is formed, for example, by applying (coating, etc.) a solvent-type or emulsion-type pressure-sensitive adhesive solution to the surface protection tape and drying it. The film thickness of the adhesive layer after drying is usually 1 to
It is 30 μm, preferably 5 to 15 μm.

The support film is not particularly limited as long as it has stretchability, and preferably polypropylene or polyester alone or those obtained by subjecting the surface thereof to an appropriate release treatment. The melting point of the support is preferably 120 to 300 ° C., more preferably 140 to 20.
It is 0 ° C. The film thickness is preferably 40 to 300 μm.
m, and more preferably 60 to 200 μm.

As a method for producing a thin layer surface protective adhesive tape, the surface protective adhesive tape is attached to one surface or both surfaces of the non-stretched support, and the temperature is higher than the melting point of the base material of the adhesive tape. Thus, uniaxial or biaxial stretching is performed.

In the method for producing a thin layer surface-protective pressure-sensitive adhesive tape of the present invention, first, the surface-protective pressure-sensitive adhesive tape is attached to one side or both sides of a stretchable support. As a method for bonding the support and the surface-protecting pressure-sensitive adhesive tape, a method using an adhesive for the surface-protecting pressure-sensitive adhesive tape can be usually mentioned. ..

Next, this is subjected to a stretching treatment. The stretching treatment is uniaxial or biaxial stretching. As the stretching method, any one of roll-type stretching, tenter-type stretching alone or in combination thereof, uniaxial stretching, sequential biaxial stretching, simultaneous biaxial stretching and the like may be used. The temperature during stretching is a temperature equal to or higher than the melting point of the substrate, and preferably a temperature equal to or lower than the melting point of the support film. This depends on the type of the base material and the support of the pressure-sensitive adhesive tape used for surface protection, but usually 100
˜170 ° C., preferably 120˜140 ° C. After stretching, the surface-protecting pressure-sensitive adhesive tape is peeled off from the support film, whereby a surface-protecting pressure-sensitive adhesive tape having a reduced film thickness can be obtained without changing the basic physical properties.

[0012]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto.

Example 1 A low-density polyethylene base material and an acrylic pressure-sensitive adhesive,
A surface protection adhesive tape with a film thickness of 60 μm
Laminated on one side of non-stretched polypropylene film,
It was stretched 3 times in the machine direction at 120 ° C. by a roll type stretching method.

Example 2 A surface-protecting adhesive tape having a thickness of 100 μm, which is composed of a low-density polyethylene base material and a polyisobutylene-based adhesive, is attached to both sides of an unstretched polypropylene film having a thickness of 100 μm, and the tenter-type stretching method is used. It was stretched 4 times in the transverse direction at 140 ° C.

Example 3 A low-density polyethylene base material and an acrylic pressure-sensitive adhesive,
Apply a surface protection adhesive tape with a thickness of 100 μm to a thickness of 100
It is laminated on one side of a non-stretched polypropylene film having a thickness of μm, stretched twice in the machine direction at 120 ° C. by a roll stretching method, and then stretched at 140 ° C. in a transverse direction by a tenter stretching method.
The film was stretched twice.

Comparative Example 1 The adhesive tape for surface protection used in Example 1 was used as it was without stretching.

Comparative Example 2 The pressure-sensitive adhesive tape for surface protection used in Example 1 was stretched twice in the machine direction at 60 ° C. by a roll-type stretching method.

Comparative Example 3 When the surface protective pressure-sensitive adhesive tape used in Example 1 was tried to be stretched 3 times in the machine direction at 60 ° C. by a roll-type stretching method, the film was broken and could not be stretched.

Experimental Example 1 Film thickness, tensile strength, elongation and cup test were carried out on the thin layer surface protective pressure-sensitive adhesive tapes produced in the above Examples and Comparative Examples, and the results are shown in Table 1. Each test method is as follows.

Film thickness of the adhesive tape The thickness was measured according to JIS Z0237.5 using a y _{1000 mm} scale dial gauge with a diameter of 5 mm.

Tensile strength, elongation According to JIS Z0237.6, width 20 mm, length 15
With a marked line at the center of the 0 mm test piece at 50 mm intervals, with a gripping interval of 100 mm, using a Shopper type pendulum type tensile tester, under conditions of 23 ° C. × 65% RH,
The load and elongation when the test piece was cut were measured by pulling at a speed of 200 mm per minute.

Cup Test The tapes of Examples and Comparative Examples were laminated on a SUS304BA plate having a diameter of 100 mm and a thickness of 0.4 mm, and a diameter of 50 m.
Drawing was performed to a depth of 20 mm with a cylindrical punch and a die of m, and after the processing, the tape was floated from the stainless plate after being left at room temperature for 24 hours, and observed.

[0023]

[Table 1]

[0024]

According to the manufacturing method of the present invention, it is possible to efficiently obtain a pressure-sensitive adhesive tape for surface protection, which is excellent in deep drawability and has a practically minimum film thickness. Therefore, the problem of industrial waste of the adhesive tape after peeling can be reduced.

Claims (1)

[Claims] 1. A thin layer surface protection, characterized in that a pressure-sensitive adhesive tape for surface protection is attached to one or both sides of a stretchable support, and stretching is carried out at a temperature not lower than the melting point of the base material of the pressure-sensitive adhesive tape. Manufacturing method for adhesive tape.