JP2616027B2 - Surface protection film - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a surface protection film for a substrate such as a metal plate, a resin-coated metal plate, a decorative plate or glass.

(Prior art) Conventionally, as a surface protective film of a substrate such as a metal plate of stainless steel, aluminum, copper, etc., a resin-coated metal plate, a decorative plate or a glass, a film of a support such as polyethylene, vinyl chloride or the like is used. An adhesive film provided with an adhesive layer mainly using rubber, acrylic rubber, butyl rubber, ethylene-vinyl acetate, or the like is generally used.

Such pressure-sensitive adhesive films are (1) environmentally contaminated by the solvent for diluting the adhesive, (2) large-scale equipment is required for coating the pressure-sensitive adhesive, and (3) adhesion by the pressure-sensitive adhesive after peeling off the pressure-sensitive adhesive film. There are many problems such as contamination of the body surface and (4) large changes in the adhesive force over time, etc., and the characteristics cannot be fully utilized in view of the problems (1) to (3). In recent years, surface protection films mainly comprising a netylene-vinyl acetate polymer have been developed and used for resin-coated steel sheets and the like.

(Problem to be Solved by the Invention) In the surface protective film mainly composed of the above-mentioned ethylene-vinyl acetate organic polymer, the problem (4) has not been sufficiently solved. In particular, an increase in the adhesive force in a pressurized state at the time of stacking and storing adherends, transporting by sea mail, or the like is a major drawback.

The present invention provides a surface protection film that has little change over time.

(Means for Solving the Problems) The present invention relates to a method of melting and mixing 2 to 45 parts by weight of a silyl-modified olefin-based organic polymer (B) formed by heating 100 parts by weight of an organic polymer (A). This is a surface protective film made of an organic polymer reacted with water in the presence of a silanol condensation catalyst.

Examples of the organic polymer (A) include ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, partially saponified or acid graft-modified ethylene-vinyl acetate copolymer, acid graft-modified polyethylene, ethylene Modified polyolefin-based organic copolymers such as vinyl acetate-methacrylic acid copolymer, ethylene-glycidyl methacrylate copolymer and ethylene-glycidyl methacrylate-vinyl acetate copolymer are used.

Production of the silyl-modified olefin-based organic polymer (B)
The method can be carried out according to the methods described in JP-B-48-1711 and JP-B-52-29338. That is, a base organic polymer of the silyl-modified organic polymer (B), a compound containing a silyl group having a hydrolyzable group, and a compound capable of generating free radicals in the organic polymer are uniformly mixed and heated. It can be carried out. Instead of adding a compound capable of generating free radicals to the organic polymer, it is also possible to generate free radicals by breaking molecular chains by mechanical treatment.

Examples of the base organic polymer of the silyl-modified organic polymer (B) include polyethylene, a copolymer of ethylene with propylene, butylene and / or hexane-1, and ethylene-
At least one of a vinyl acetate copolymer and an ethylene-ethyl acrylate copolymer can be used, but low density polyethylene is preferably used.

Examples of the compound containing a silyl group having a hydrolyzable group include, in addition to a hydrolyzable organic group such as a methoxy group, an ethoxy group, and a butoxy group, and an alkoxy group, a formyloxy group, an acetoxy group, a brobionoxy group, and an alkyl group. Compounds containing an amino group, an arylamino group, and the like, and having an aliphatically unsaturated hydrocarbon group or a hydrocarbonoxy group reactive with a free radical site generated in the organic polymer are preferable. Representative examples include vinyltrimethoxysilane, vinyltriethoxysilane, and vinyltriacetoxysilane.

Compounds that can generate free radicals in the organic polymer include dicumyl peroxide, benzoyl peroxide, 2,
Organic peroxides such as 5-dimethyl-2,5-di (tert-butylperoxy) hexyne-3 and azo compounds such as azobisisobutyronitrile and dimethylazoisobutyrate can be mentioned.

The amount of addition of the silyl-modified olefin-based organic polymer (B) to 100 parts by weight of the organic weight (A) is 5 to 45 parts by weight, and if it exceeds 45 parts by weight, sufficient initial adhesion to the adherend is obtained. This is economically disadvantageous because the ratio of other pellets that cannot be used increases. On the other hand, when the amount is less than 2 parts by weight, the change of the adhesive force over time is large, and not only there is a defect particularly for surface protection, but also when it is used for thermal bonding, bleeding due to flow during heating and pressurizing. Part significantly impairs the product appearance.

The method of mixing the organic polymer (A) and the silyl-modified olefin-based organic polymer (B) is not particularly limited, but is weighed to a predetermined mixing ratio, premixed by a Henschel mixer or the like, and then put into an extruder hopper and rotated by a screw. It can be mixed by action.

Examples of the silanol condensation catalyst include dibutyltin dilaurate, dibutyltin diacetate, dibutyltin dioctoate, stannous acetate, lead naphthenate, and a series of dioctyltin compounds, acids such as inorganic acids and fatty acids, ethylamine, dibutylamine. And an organic base such as hexylamine.

The organic polymer composition [(organic polymer (A) + silyl-modified olefin-based organic polymer (B)] 100 parts by weight,
05 to 10 parts by weight, preferably 0.01 to 1 part by weight.
The silanol condensation catalyst is generally used as a master hatch for the silyl-modified olefin-based organic polymer (B). However, as described in JP-B-52-34651, it is necessary to directly weigh the silanol directly into an extruder. , Water or the like, or a solution of a solvent such as toluene.

The organic polymer of the present invention may optionally contain additives such as an antioxidant, a surfactant, a filler, a tackifier, and an ultraviolet absorber. In particular, when used as a surface protective agent, by adjusting the amount of surfactant and / or filler added, there is an effect of suppressing the change over time of the adhesive force. , Silica, by using a filler such as calcium carbonate,
There is an advantage that the flow such as heat bonding can be suppressed to some extent and the appearance of the product is not impaired.

The organic polymer of the present invention is generally used in the form of a film or sheet, and a conventional film or sheet forming machine can be used for molding. For example, in the case of a film, a T-die method (cooling roll method, water tank method) and an inflation method (upward, downward) can be adopted.

The organic polymer obtained in the present invention can be subjected to a plasma treatment, a corona treatment, a flame treatment, a chemical treatment, and the like, which are generally performed as a post-treatment. Can also.

(Action) In the present invention, since a crosslinked structure is introduced into the contact layer with the adherend, the flow of molecules is suppressed, and when used as a pressure-sensitive adhesive film, it has an action of suppressing a change in adhesive force with time.

Examples 1 to 8 With the composition shown in the attached table, using an extruder with a diameter of 65 mm,
Extrude a 65μ thick film by T-die-water tank method,
4 hours treatment at 90 ° C.-humidity. As shown in the drawing, this film (surface protective film) 1 was passed through a roll 4 and an aluminum plate (thickness: 1 mm) 3 heated to 80 ° C. on a hot plate 2, heat-bonded, and cooled at room temperature for 20 minutes. , 20 in 90 degree direction
The results obtained by performing a peeling test at 0 mm / min are shown in the attached table as initial values. Further, the adhesive obtained above was heated at 65 ° C.
After leaving it at 10kg / cm2 for 7 days, apply 20 degrees in the same direction as above.
A peel test was performed at 0 mm / min to evaluate the peel strength.

Comparative Examples 1 to 3 A film having a thickness of 65 μm was produced in the same manner as in the Example except that the compositions shown in the attached table were used, and the results of the thermal adhesion test at 80 ° C. and 180 ° C. are shown in the attached table.

(Results of the Invention) As described above, the surface protective film of the present invention eliminates the drawbacks that the adhesive force has little change with time and is difficult to peel off, and protects the transfer of the adhesive and the like as in the case of the film with the adhesive. No surface contamination of the material occurs. Furthermore, since an adhesive coating process is not required as in the production of a film with an adhesive, there is no air pollution by a solvent or the like, and the environment is extremely excellent.

[Brief description of the drawings]

The drawing is a side view showing a method of bonding a surface protective film and an adherend. DESCRIPTION OF SYMBOLS 1 ... Surface protection film 2 ... Hot plate 3 ... Aluminum plate 4 ... Roll

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location B32B 17/10 B32B 17/10

Claims (4)

(57) [Claims] 1. An organic polymer (A) (100 parts by weight) is melt-mixed with 2 to 45 parts by weight of a silyl-modified olefin-based organic polymer (B) formed by heating under the presence of a silanol condensation catalyst. A surface protection film for a substrate, comprising an organic polymer obtained by reacting water with water. 2. The organic polymer (A) has at least one of an ethylene-vinyl acetate copolymer, an ethylene-ethyl acrylate copolymer and a partially saponified ethylene-vinyl acetate copolymer having a melt index of more than 20. The surface protective film according to claim 1, which is one kind. 3. The surface protective film according to claim 1, wherein the organic polymer (A) is an ethylene-vinyl acetate copolymer containing 10% by weight or more of vinyl acetate. 4. Silyl-modified olefin organic polymer (B)
4. The surface protective film according to claim 1, wherein the base organic polymer is at least one of polyethylene, a copolymer of ethylene and propylene, butylene and / or hexene-1.