JP3061676B2 - Surface protection film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a surface protective film having excellent sticking properties and excellent spreadability, which is used to protect the surface of a protected object such as a metal plate or a coated coated steel plate. .

[0002]

2. Description of the Related Art Conventionally, the surface of a protected object such as a metal plate such as a stainless steel plate or an aluminum plate, a coated steel plate such as a color steel plate, or a synthetic resin plate such as a hard vinyl chloride plate during transportation or storage is known. 2. Description of the Related Art In order to prevent stains and scratches, a surface protection film is attached to a surface of an object to be protected before transportation or storage to protect the object.

[0003] Also, shearing, punching,
2. Description of the Related Art At the time of processing such as bending and drawing, in order to prevent the surface from being stained or damaged, processing is performed by attaching a surface protection film to the surface of a protected object.

[0004] As a surface protective film for such a purpose, for example, Japanese Patent Application Laid-Open No. 62-201985
As described in No. 2, the density of the substrate film is 0.90
100 parts by weight of a linear low-density polyethylene resin (a) having an MI of 1 to 8 g / 10 min at 0.95 g / cm ³ and optionally a polyolefin resin other than the component (a) 5 to 50
A surface protective film using a mixture of parts by weight has been proposed.

[0005]

However, since this surface protective film has a low tensile elasticity and is attached in a stretched state when attached to the surface of an object to be protected, the surface protective film has to be adhered in a stretched state. There has been a problem that the surface protection film shrinks after a certain period of time, and the surface protection film spontaneously peels off from the object to be protected.

However, when deep drawing is performed with the base film adhered to the surface to be protected, the base film is made of soft vinyl chloride, which is a material having excellent sticking properties and excellent spreadability. May be used.
However, when this surface protective film is used, chlorine gas is generated when the surface protective film is peeled off from the object to be protected after being used and incinerated in an incinerator or the like, which is not preferable in terms of occupational health. And there was a problem that it was necessary to provide a device for removing chlorine gas in the incinerator from the viewpoint of environmental hygiene.

[0007] The present invention solves the above-mentioned conventional problems and does not spontaneously peel off after a certain period of time after being adhered to the surface of a protected object, and remains adhered to the surface of the protected object. An object of the present invention is to provide a surface protective film that does not break when subjected to deep drawing or the like, completely prevents the surface from being stained or scratched, and does not generate toxic components such as chlorine gas when incinerated. It was done as.

[0008]

The present invention relates to a surface protective film having a pressure-sensitive adhesive layer provided on one side of a base film, wherein the base film has a density of 0.921 to 0.960 g /
relative to 100 parts by weight of polyethylene is cm ^3, and density of 0.890~0.920g / cm ³ linear low-density polyethylene or ultra low density polyethylene from 20 to 180
Parts by weight of the resin mixture , and
It is a surface protective film having a modulus of 1300 to 1800 kg / cm ² .

In the present invention, as one of the main raw materials for the base film, a density of 0.921 to 0.960 g / cm
A polyethylene of ³ is used. As long as the density is within this range, any of low-density polyethylene, medium-density, polyethylene, and high-density polyethylene can be used, and they may be used alone or in combination of two or more. When the density is less than 0.921 g / cm ³ ,
When the tensile modulus of the film is too low and the surface protective film is stretched when pasted on the surface of the protected object, the surface protective film shrinks after a certain period of time after pasting, Then, the surface protection film is spontaneously peeled off from the protected object. Conversely, 0.96
If it exceeds 0 g / cm ³ , the moldability of the film will be remarkably reduced, and the molding will be difficult. M of this polyethylene
I is not particularly limited as long as it is within a range in which it can be formed into a film, but preferably, 0.2 to 30 g / 10
Min, more preferably in the range of 0.5 to 20 g / 10 min.

In the present invention, linear low-density polyethylene (hereinafter abbreviated as LLDPE) or ultra-low-density polyethylene (hereinafter abbreviated as VLDPE) used as a mixture with the above polyethylene is generally used. , A copolymer of ethylene and an α-olefin is used. Then, what its density exceeds 0.91 g / cm ³ LLDPE, density 0.91 g / cm ³ or less of what is called VLDPE.

[0011] LLDPE or VLDPE is, C ₄ system (comonomer butene -1), C ₆ system (comonomer hexene) and the like, depending on the type of ethylene copolymerized with α- olefins, are classified into several In the present invention, any density can be used as long as the density is in the range of 0.890 to 0.92 g / cm ³ . If the density is less than 0.890 g / cm ³ , the tensile elasticity is too low, and the material is spontaneously exfoliated from the protected object as described above. Conversely, if the density exceeds 0.920 g / cm ³ , tensile too elastic modulus becomes high, poor spreadability in the case of a surface protective film, intends want to film rupture when subjected to deep drawing by attaching to the protected object. L LDP
E or MI of VLDPE is not particularly limited as long as it is within a range that can be formed into a film, but preferably,
0.2 to 30 g / 10 min, more preferably 0.5 to 2
A range of 0 g / 10 minutes is preferred.

The amount of LLDPE or VLDPE is 20 to 18 parts by weight based on 100 parts by weight of the polyethylene.
It must be 0 parts by weight. If the addition amount is less than 20 parts by weight, the tensile elasticity as a surface protective film becomes too high and the spreadability is poor, and the film breaks when deep drawing is performed while being adhered to the protected object. I will. On the other hand, if it exceeds 180 parts by weight, the tensile elastic modulus of the surface protective film becomes too low, so that it is spontaneously peeled off from the object when it is adhered to the object as described above.

The above resin mixture is formed into a film,
An adhesive layer is provided on one side to form a surface protection film. Base
As described above, if the tensile modulus of the material film is too low,
The surface protection film spontaneously peels off from the protected object,
Conversely, if it is too high, the spreadability of the surface protective film
Poor, when applied to a protected object and deep drawn
Since the film breaks, 1300-1800k
g / cm ² .

In the present invention, the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer provided on one side of the substrate film is not particularly limited as long as it is a pressure-sensitive adhesive composition generally used for a surface protective film, a pressure-sensitive adhesive tape and the like. Examples thereof include a rubber-based pressure-sensitive adhesive, an acrylic-based pressure-sensitive adhesive, and an ethylene / vinyl acetate copolymer.

In the present invention, as a method for producing a surface protective film, the same method as that of a general surface protective film can be employed. For example, the surface protective film is previously extruded by an extrusion method or a T-die method. After the base material film is manufactured, the adhesive composition may be dissolved in a solvent and applied and dried on the base film, or the resin mixture of the base film and the adhesive composition may be inflation-processed or T-die It may be manufactured by a multi-layer coextrusion method extruding simultaneously by a method or the like.

The thickness of the surface protective film of the present invention is not particularly limited as long as it can function to prevent the object to be protected from being stained or scratched without being broken. 200 μm is preferred.

The surface protective film of the present invention is suitably used for protecting the surface of a metal plate such as a stainless steel plate or an aluminum plate, a coated steel plate such as a color steel plate, or a synthetic resin plate such as a hard vinyl chloride resin plate. .

[0018]

The surface protective film of the present invention has a base film having a density of 0.890 to 100 parts by weight of polyethylene having a density of 0.921 to 0.960 g / cm ^3.
0.920 g / cm ³ , made of a resin mixture to which 20 to 200 parts by weight of linear low-density polyethylene or ultra-low-density polyethylene is added , and having a tensile modulus of 130
Since it is limited to 0 to 1800 kg / cm ² and the tensile modulus is not too low, it does not peel off spontaneously when applied to an object to be protected, and the tensile modulus is too high.
It has excellent spreadability and does not break when applied to the surface of a protected object and subjected to deep drawing, etc., completely preventing dirt and scratches on the surface of the protected object In addition, since the base film is made of polyethylene, no toxic components such as chlorine gas are generated during incineration.

[0019]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. Example 1 Production of surface protective film Low density polyethylene (LDPE) [manufactured by Mitsui Petrochemical Company:
Product name “Mirason”, density: 0.923 g / cm ³ , M
I: 3.7 g / 10 min] to 100 parts by weight of LLD
PE [manufactured by Tosoh Corporation: trade name "Nipolon @ Z ZF230"
─1 ”, density: 0.920 g / cm ³ , MI: 2.0 g
/ 10 min] to obtain a resin mixture for a base film obtained by adding 150 parts by weight of an ethylene-vinyl acetate copolymer (manufactured by Mitsui-Dupont Polychemical Co., Ltd .: trade name “Evaflex EV260”, vinyl acetate content ( VAC): 2
8% by weight, MI: 6.0 g / cm ³ ] as the adhesive composition, the thickness of the base film was 60 μm, and the thickness of the adhesive layer was 2
A surface protection film was obtained by a T-die coextrusion method so as to have a thickness of 0 μm. A base film alone was produced in the same manner as described above except that the adhesive layer was not provided, and the tensile modulus in the longitudinal direction was measured to be 1450 kg / cm ² . In addition, the tensile elasticity was measured by a tensile tester using a test piece having a width of 10 mm and a length of 900 mm and a tensile speed of 500 m.
It was measured in m / min.

Evaluation of Sticking Performance of Surface Protective Film The obtained surface protective film was applied to a laminator 1 as shown in FIG. 1 at room temperature, and the tension of the surface protective film was 2 kg per unit width (indicated by F in the figure). / M and a linear pressure of the laminator 1 of 76.6 kg / cm under JIS Z
Stainless steel plate according to 0237 (thickness 1 mm)
3 was attached to the surface. After leaving this at room temperature for 7 days, the state of the presence or absence of spontaneous peeling of the surface protective film was observed. Table 1 shows the results.

Breakage during drawing of surface protective film
Evaluation addition of, as shown in FIG. 2, the sample cut from the stainless steel plate (thickness 1 mm) 3 which was attached a surface protective sheet 2 by the same method as described above, by using the drawing device 4, the sample fixing part 41 It was fixed and pressed cold from above by the male mold 42, and deep drawing was performed so as to form a curved shape with a drawing depth of 10 mm and 30 mm. The state of breakage of the surface protective film during the deep drawing was observed. The results are shown in Table 1.

Example 2 A surface protective film was obtained in the same manner as in Example 1 except that the amount of LLDPE was changed to 20 parts by weight. A base film alone was produced in the same manner as described above except that the adhesive layer was not provided, and the tensile modulus in the longitudinal direction was measured in the same manner as in Example 1. As a result, it was 1800 kg / cm ² . About the obtained surface protective film, similarly to Example 1, evaluation of the sticking performance and observation of the state of breakage during deep drawing were performed. Table 1 shows the results.

Example 3 Instead of 100 parts by weight of LDPE, high-density polyethylene (HDPE) [manufactured by Mitsubishi Kasei Kogyo Co., Ltd .: trade name "JS030"]
R ", density: 0.955 g / cm ³ , MI: 3.0 g / cm
[10 minutes] A surface protective film was obtained in the same manner as in Example 1 except that 100 parts by weight was used. A base film alone was produced in the same manner as described above except that the adhesive layer was not provided, and the tensile modulus in the longitudinal direction was measured in the same manner as in Example 1. As a result, it was 1750 kg / cm ² . About the obtained surface protective film, similarly to Example 1,
Evaluation of the sticking performance and observation of the breaking state during deep drawing were performed. Table 1 shows the results.

Example 4 Instead of 150 parts by weight of LLDPE, VLDPE [manufactured by Sumitomo Chemical Co., Ltd .: Exelen VL200], density: 0.900
g / cm ³ , MI: 2.0 g / 10 min], and a surface protective film was obtained in the same manner as in Example 1 except that 100 parts by weight was used. Except that the adhesive layer was not provided, a base film alone was produced in the same manner as above, and its longitudinal tensile modulus was measured in the same manner as in Example 1.
It was 00 kg / cm ² . About the obtained surface protective film, similarly to Example 1, evaluation of the sticking performance and observation of the state of breakage during deep drawing were performed. Table 1 shows the results.

Example 5 Instead of 150 parts by weight of LLDPE, VLDPE [Exelen VL200 manufactured by Sumitomo Chemical Co., Ltd., density: 0.900]
g / cm ³ , MI: 2.0 g / 10 min], and a surface protective film was obtained in the same manner as in Example 1 except that 20 parts by weight was used. Except that the adhesive layer was not provided, a base film alone was produced in the same manner as above, and the tensile modulus in the longitudinal direction was measured in the same manner as in Example 1.
It was 0 kg / cm ² . About the obtained surface protective film, similarly to Example 1, the observation of the sticking performance and the state of breakage during deep drawing were performed. Table 1 shows the results.

Comparative Example 1 A surface protective film was obtained in the same manner as in Example 1 except that the amount of LLDPE was changed to 5 parts by weight. Except that the adhesive layer was not provided, only the substrate film was produced in the same manner as described above, and the tensile modulus in the longitudinal direction was measured in the same manner as in Example 1. As a result, it was 2,000 kg / cm ² . About the obtained surface protective film, similarly to Example 1, the observation of the sticking performance and the state of breakage during deep drawing were performed. Table 1 shows the results.

Comparative Example 2 Except that the amount of LLDPE added was 200 parts by weight,
In the same manner as in Example 1, a surface protective film was obtained. Except that the adhesive layer was not provided, only the substrate film was manufactured in the same manner as described above, and the tensile modulus in the longitudinal direction was measured in Example 1.
It was 1200 kg / cm < ² > when it measured similarly. About the obtained surface protective film, Example 1
Similarly to the above, the observation of the sticking performance and the state of breakage during deep drawing were performed. Table 1 shows the results.

Comparative Example 3 A surface protective film was obtained in the same manner as in Example 1 except that LLDPE was not added. Except that the adhesive layer was not provided, only the substrate film was produced in the same manner as described above, and the tensile modulus in the longitudinal direction was measured in the same manner as in Example 1. As a result, it was 2,000 kg / cm ² . The observation of the sticking performance and the state of breakage during deep drawing were performed. Table 1 shows the results.

[0029]

[Table 1]

[0030] As is apparent from Table 1, in the case of Examples 1 to 5, all without spontaneously peel even after pasting a certain period of time on the surface of the article to be protected, and the protected product It does not break when applied to the surface and deep drawn. On the other hand, as in Comparative Examples 1 and 3, L
If the amount of LDPE added is small or not added, the tensile elasticity of the base film is too high, and it breaks when it is attached to the surface of the protected object and subjected to deep drawing. and will, also as in Comparative example 2, when the added amount of LLDPE is large, the tensile modulus of the base film is too low, naturally peeled after a certain period of time adhered to the surface of the article to be protected
I have.

[0031]

The surface protective film of the present invention is configured as described above, so that it does not peel off spontaneously when applied to the object to be protected. When it is performed, it does not break and can completely prevent the surface of the protected object from being stained or scratched, and since the base film is made of polyethylene, no toxic components such as chlorine gas are generated during incineration.

[0032]

[Brief description of the drawings]

FIG. 1 is a front view showing a state where a surface protective film obtained by the present invention is laminated on a sunteres board.

FIG. 2 is a front view showing a state in which the stainless steel plate to which the surface protective film obtained in the present invention is applied is deep drawn by a deep drawing machine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laminator 1 2 Surface protection film 3 Stainless steel plate 4 Deep drawing apparatus 41 Sample fixing part 42 Male type

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C09J 7/02 B05D 5/10 B05D 7/04 B32B 7/10 B32B 27/32

Claims (1)

(57) [Claims] Claims: 1. A surface protective film having an adhesive layer provided on one side of a base film, wherein the base film has a density of 0.921 to 0.960 g / cm ³ with respect to 100 parts by weight of polyethylene. Density 0.890-0.920
g / cm ³ , made of a resin mixture to which 20 to 180 parts by weight of linear low-density polyethylene or ultra-low-density polyethylene is added , and having a tensile modulus of 1300 to 1800.
surface protective film, which is a kg / cm ^2.