JPH09174771A - Adhesive film for surface protection - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film for surface protection which is not broken in the case when thrust-bend machining or the like is applied to a plate-shaped material whereon the film is stuck, and prevents the plate-shaped material from being impaired and which can be cut excellently in the case when the plate- shaped material is subjected to die cutting, and is excellent in transparency. SOLUTION: An adhesive film for surface protection prepared by forming an adhesive layer on one surface of a film base, which is formed of resin containing polyethylene manufactured by using a metallocene catalyst and of which the tensile breaking strength is 3.0kg/cm<2> or above.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an adhesive film for surface protection (including a sheet and a tape),
The present invention relates to an adhesive film used for surface protection of a plate-like material, particularly a metal plate such as a stainless steel plate, an aluminum plate, a steel plate, or a coated steel plate. In particular, the present invention provides a pressure-sensitive adhesive film for surface protection, which is excellent in workability such as bending a metal plate.

[0002]

2. Description of the Related Art Heretofore, as a pressure-sensitive adhesive film for protecting the surface of a plate-like material such as a metal plate as described above, a pressure-sensitive adhesive film based on a soft vinyl chloride film or a polyolefin film has been known. For a plate-shaped object that is subjected to V-shaped bending and the like by a pressing machine, an adhesive film for surface protection using a soft vinyl chloride film as a substrate is generally used. This is because the strength (tensile rupture strength) of the soft vinyl chloride film is superior to that of the polyolefin resin. Thus, in the pressure-sensitive adhesive film for surface protection, the properties of the material of the film substrate greatly contribute to the surface protection function of the pressure-sensitive adhesive film. However, an adhesive film for surface protection that uses a soft vinyl chloride film as a base material, when bonded to a plate-like object in cold weather such as in winter, the soft vinyl chloride-based film becomes hard, and it can be successfully adhered to the plate-like object. There is a problem that there is no. In addition, there is a problem that when the surface-protecting pressure-sensitive adhesive film finally peeled off from the plate-shaped product or its molded product is recovered and incinerated, it has an adverse effect on the environment.

Recently, in a polyolefin resin, a density of 0.910g / cm ³ ~0.925g / cm ³ low-density polyethylene ^{(LDPE), 0.926g / cm 3} ~0.940g /
cm ³ Medium Density Polyethylene (MDPE), 0.941g / c
High density polyethylene (HDP of m ^{3 to} 0.965 g / cm ³
An adhesive film for surface protection based on E) is used. However, when the adhesive film for surface protection using LDPE or MDPE as a base material is used for the above-mentioned V-shaped bending processing application, the film base material has a small tensile rupture strength, so that the film is ruptured during processing, resulting in a plate-like shape. There is a risk of scratching the object. The surface protection adhesive film based on HDPE has a high breaking strength, but it is inferior in transparency. Therefore, after the adhesive film is attached to the plate-shaped product, the surface damage or the pattern of the plate-shaped product is not observed. It may not be possible to judge visually.

Polypropylene (PP) resin alone and P
A blended film of P resin and other polyolefin resin may be used as the base material of the adhesive film for surface protection, but since these are generally stretched and have directionality, they are well-suited for punching during metal working. It may not be possible to punch through. Further, since the blended film is inferior in transparency, the same problem as that of the HDPE occurs.

[0005]

DISCLOSURE OF THE INVENTION The present invention does not tear the plate-shaped article having the surface-protective pressure-sensitive adhesive film attached thereto, and does not damage the plate-shaped article when the plate-shaped article is bent or folded. Moreover, it is an object of the present invention to provide an adhesive film for surface protection, which can be cut well when a plate-shaped product is punched and which is excellent in transparency.

[0006]

Means for Solving the Problems The present inventors have conducted a study on a base material having good processability in a pressure-sensitive adhesive film for surface protection using the above-mentioned polyolefin film as a base material, and as a result, a metallocene catalyst was used. By using a film substrate formed of a resin including a polyethylene resin produced by the above and having a tensile breaking strength of 3.0 kg / cm ² or more, it is possible to sufficiently satisfy the function required for the surface protective adhesive film. Found and completed the present invention.

That is, the surface-protective pressure-sensitive adhesive film of the present invention is a surface-protective pressure-sensitive adhesive film in which a pressure-sensitive adhesive layer is formed on one surface of a film substrate, and the film substrate is manufactured using a metallocene catalyst. It is characterized in that it is formed of a resin containing polyethylene and that the film substrate has a tensile breaking strength of 3.0 kg / cm ² or more. The tensile breaking strength in the present invention is JIS K 7127.
According to the above, the value is measured under the condition of a pulling speed of 200 mm / min. The film substrate may be formed of a resin obtained by blending polyethylene produced using a metallocene catalyst and a polyolefin resin other than that.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Polyethylene used as a main material of a film substrate in the present invention is polyethylene produced by using a metallocene catalyst as a catalyst, and conditions other than the catalyst are in accordance with ordinary methods. It can be manufactured. The metallocene catalyst is, as shown below, a catalyst system comprising a metallocene compound represented by the general formula [I] and an alkylalumoxane represented by the general formula [II] or the general formula [III] which is a cocatalyst. Is generally soluble in an organic solvent and has a single type of catalytic active site.

[0009]

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(Wherein R ¹ is hydrogen or an alkyl group,
M represents a transition metal and X represents halogen. )

[0011]

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[0012]

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(In the formula, R ² represents an alkyl group, and n is 2
Represents an integer of -20. )

In the metallocene compound represented by the general formula [I], the alkyl group is a methyl group, an ethyl group,
Examples thereof include a butyl group, an isobutyl group and a t-butyl group. Examples of the transition metal contained in the metallocene compound represented by the general formula [I] include zirconium, titanium and hafnium. In the metallocene compound represented by the general formula [I], examples of halogen include chlorine, bromine, iodine and boron, and chlorine is preferably used.

In the alkylalumoxane represented by the general formula [II] or the general formula [III], the alkyl group is a methyl group, an ethyl group, a butyl group, an isobutyl group or t-
Examples thereof include a butyl group, and preferably a methyl group is used.

Examples of polyethylene produced using the metallocene catalyst as described above include those described in "Industrial Materials", Nikkan Kogyo Shimbun, Ltd., 1995, pp. 34-45. To be done. Specifically, Kernel 65FI, Kernel 64FT (both are trade names, manufactured by Mitsubishi Chemical Co., Ltd.), EXACT (trade name, manufactured by Exxon Chemical Co., Ltd.), AFFINITY, ENGAGE
(Both are trade names, manufactured by Dow Chemical Co.)
Preferably, the kernel 65FI and the kernel 64FT are used.

The film substrate used in the present invention is formed of a resin containing polyethylene produced by using the above metallocene catalyst. Even if the polyethylene resin by the metallocene catalyst is used alone, the polyethylene resin and other polyolefins can be used. It may be a blended resin with a resin. Examples of the polyolefin resin other than the polyethylene resin produced using the metallocene catalyst include, for example, low density polyethylene (LDPE), medium density polyethylene (MDPE) or high density polyethylene (HDPE) produced by a method other than the method using the metallocene catalyst. , Polypropylene (PP), ethylene vinyl acetate copolymer (EVA), ethylene ethyl acrylate (EEA), etc. are preferably used, and LDPE, MDPE, HDP are particularly preferable.
E and PP. When the resin is blended, the tensile breaking strength of the obtained resin should be 3.0 kg / cm ² or more.

The resin used as the material of the film substrate may contain additives such as antioxidants, ultraviolet absorbers, light stabilizers, lubricants, blocking agents and pigments.

The tensile strength at break of the film substrate used in the present invention is 3.0 kg / cm ² or more. When the tensile breaking strength of the film base material is less than 3.0 kg / cm ² , the film base material is likely to be broken during bending, which may damage the plate-like material.

Further, the transparency of the film substrate (HAZE:
(Measured according to JIS K 7105) is preferably 30% or less.

The thickness of the film substrate used in the present invention is generally 40 μm to 150 μm, preferably 60 μm to 120 μm.

As the pressure-sensitive adhesive used in the present invention, a pressure-sensitive pressure-sensitive adhesive is preferably used, and it is not necessary to use a special one for the purpose of the present invention. You can use it. For example,
Examples include natural rubber adhesives and acrylic adhesives.

The thickness of the adhesive layer is 5 μm to 30 μm after drying.
m is preferable.

The surface-protective pressure-sensitive adhesive film of the present invention is produced by forming a layer comprising the above-mentioned pressure-sensitive adhesive on one side of a film substrate by a means known per se.

[0025]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.
With respect to the pressure-sensitive adhesive films for surface protection obtained in the following Examples 1 to 3 and Comparative Examples 1 to 4, the transparency, bending workability, tensile breaking strength, and 0 ° C. laminating property described below were measured.

Example 1 Polyethylene resin produced using a metallocene catalyst [manufactured by Mitsubishi Chemical Co., trade name: Kernel 65FI, MFR
(Melt flow rate) 2.2 g / 10 min, d = 0.
910 g / cm ³ ] was extruded into a film having a thickness of 100 μm by an inflation melt extruder, and this was used as a film substrate, and a pressure-sensitive adhesive composed mainly of acrylic rubber was provided on one surface of the film after drying the adhesive layer. The coated film was dried so as to have a thickness of 10 μm, and an adhesive film for surface protection was obtained.

Example 2 Polyethylene resin manufactured using a metallocene catalyst (trade name: Kernel 64FT, MFR manufactured by Mitsubishi Chemical Co., Ltd.)
3.5 g / 10 min, d = 0.910 g / cm ³ ) was extruded with a T-die melt extruder into a film having a thickness of 100 μm, which was used as a film base material, and one side of which had acrylic rubber as the main component. The thickness after drying the pressure-sensitive adhesive is 10 μm
And dried to obtain a pressure-sensitive adhesive film for surface protection.

Example 3 LDPE (manufactured by Mitsui Petrochemical Co., Ltd., trade name: Mirason 16P, MFR 3.7) based on 100 parts by weight of a polyethylene resin produced using the same metallocene catalyst as in Example 1
g / 10 min, d = 0.923 g / cm ³ ) was mixed in an amount of 15 parts by weight to obtain a film substrate in the same manner as in Example 1. The same pressure-sensitive adhesive as in Example 1 was applied and dried to obtain a surface. A protective adhesive film was obtained.

Comparative Example 1 LDPE (manufactured by Mitsui Petrochemical Co., Ltd., trade name: Mirason 1
6P, MFR 3.7g / 10min, d = 0.923g / c
m ³ ) was used to obtain a film substrate in the same manner as in Example 1, and the same pressure sensitive adhesive as in Example 1 was applied and dried to obtain an adhesive film for surface protection. The obtained pressure-sensitive adhesive film for surface protection was inferior in tensile rupture strength and was less than 3.0 kg / cm ^{2 in} both MD and TD.

Comparative Example 2 LDPE of Comparative Example 1 was added to 70 parts by weight of the polyethylene resin produced by using the metallocene catalyst of Example 1.
Part by weight was mixed and a film substrate was obtained in the same manner as in Example 1. The same pressure-sensitive adhesive as in Example 1 was applied and dried to obtain an adhesive film for surface protection. The obtained pressure-sensitive adhesive film for surface protection was inferior in tensile rupture strength and was less than 3.0 kg / cm ^{2 in} both MD and TD.

Comparative Example 3 HDPE (Mitsui Petrochemical Co., Ltd., trade name: Hi-Zex 3
300F, MFR 1.1g / 10min, d = 0.954
g / cm ³ ) was used to obtain a film substrate in the same manner as in Example 1, and the same pressure sensitive adhesive as in Example 1 was applied and dried to obtain an adhesive film for surface protection. The obtained adhesive film for surface protection was inferior in transparency.

Comparative Example 4 100 parts by weight of polyvinyl chloride (degree of polymerization = 1100), 30 parts by weight of dioctyl phthalate, 0.6 parts by weight of barium stearate, and 0.6 parts by weight of zinc stearate were blended by a calendering method. Roll-molding was performed to obtain a film base material having a thickness of 100 μm, and the same pressure-sensitive adhesive as in Example 1 was applied and dried to obtain an adhesive film for surface protection. The obtained pressure-sensitive adhesive film for surface protection was inferior in the 0 ° C. laminating property.

The physical properties of the pressure-sensitive adhesive films for surface protection obtained in Examples 1 to 3 and Comparative Examples 1 to 4 were measured and evaluated by the following methods. Table 1 shows the results.

* 1) Transparency (HAZE:%): JIS
It was measured according to K 7105.

* 2) Bending workability: adherend SU shown in FIG.
S304BA board 1 (in FIG. 1, t = 2 mm, A = 30 m
m, B = 50 mm) with a surface protection film attached,
Bending die 2 shown in FIG. 2 (in FIG. 2, L = 16 mm, R
= 1 mm, θ = 90 °) and processed by using the punch 3. After the processing, when the tear of the pressure-sensitive adhesive film for surface protection or the scratch on the adherend did not occur, it was marked with O, and when it did, it was marked with X.

* 3) Tensile breaking strength: JIS K 71
According to No. 27, the measurement was performed under the condition of a pulling speed of 200 mm / min.

* 4) Laminating property at 0 ° C .: A roll-shaped tape with a width of 400 mm and a length of 100 m was used as a surface protective film, and a 100φ neoprene rubber laminating machine (laminating speed: 50 m / min) was used at 0 ° C. atmosphere. Using this tape, SU with a thickness of 0.8 mm, a width of 400 mm and a length of 1 m
The S304BA finishing plate was attached, and the state of wrinkles in the tape at that time was examined. The one that was applied without wrinkles was evaluated as ◯, and the one that caused wrinkles was evaluated as x.

[0038]

[Table 1]

[0039]

EFFECTS OF THE INVENTION According to the present invention, when a plate-shaped article having a surface protective film attached thereto is subjected to a bending process, a folding bending process, or the like, the plate-shaped product is not broken and the plate-shaped product is not scratched, and the plate-shaped product is not damaged. It is possible to provide a surface protection film that can be cut well when a blank is punched. Furthermore, since the surface protective film of the present invention is excellent in transparency, it is possible to easily visually judge the surface scratches or patterns of the plate-shaped product when the pressure-sensitive adhesive film is attached to the plate-shaped product.

[Brief description of the drawings]

FIG. 1 Adherend SUS304B used for bending workability test
It is a perspective view showing A board 1. In the figure, t = 2 mm, A = 3
0 mm and B = 50 mm.

FIG. 2 is a cross-sectional view showing a bending mold 2 used in a bending workability test. In the figure, L = 16 mm, R = 1 mm, θ =
It is 90 °.

Claims (2)

[Claims] 1. A pressure-sensitive adhesive film for surface protection, comprising a pressure-sensitive adhesive layer formed on one surface of a film substrate, wherein the film substrate is formed of a polyethylene-containing resin produced using a metallocene catalyst, and An adhesive film for surface protection, characterized in that the tensile strength of the film base material is 3.0 kg / cm ² or more. 2. The pressure-sensitive adhesive film for surface protection according to claim 1, wherein the film substrate is formed of a resin obtained by blending polyethylene produced using a metallocene catalyst and a polyolefin resin other than the polyethylene.