JP3399183B2 - Automotive coating protection film - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating film protective film for automobiles, and more particularly, to an automobile which can maintain a stable adhered state when necessary during transportation or storage of the automobile and has good operability during peeling. Coating film protective film.

[0002]

2. Description of the Related Art A coated article such as an automobile is transported by a ship, a trailer, a freight car, etc., or is temporarily stored indoors or outdoors until it reaches a user's hand. At this time, defects such as stains, scratches, discoloration, and contamination may occur on the surface of the coated product due to the effects of rain (acid rain), iron powder, dust, salts, sun rays, and the like, which may deteriorate product quality.

Conventionally, in the automobile industry, in order to prevent such a problem, a protective coating made of wax is formed on the coating surface, but it is difficult to apply a wax coating uniformly. However, there are problems that uniform protection cannot be obtained, that a great deal of labor is required to apply and remove the wax coating film, and that a sufficient protective effect cannot be expected.

On the other hand, for example, as a temporary surface protection method for color coated steel plates, stainless steel plates, aluminum steel plates and various other products, conventionally, a peelable protective adhesive film is attached to the surface of these base materials. (For example, JP-A-50-52141 and JP-A-51-1).
07333, JP-A-54-126243, JP-A-5
No. 8-145775, JP-A No. 63-117087, etc.), it has been proposed to attach such a peelable protective pressure-sensitive adhesive film as a method for protecting the painted surface of an automobile.
It has been put to practical use in recent years (for example, Japanese Patent Laid-Open No. 2-30028).
No. 1, JP-A-5-237935, JP-A-5-2379.
37, JP-A-5-278108, and JP-A-6-733.
52, JP-A-6-128540, etc.).

As such a film for protecting a coating film for automobiles, for example, a film base made of various resins such as polyurethane, polyimide, nylon, polyethylene, polypropylene, polyester, polycarbonate and soft vinyl chloride resin can be used. System, styrene-butadiene copolymer rubber, synthetic rubber system such as polyisobutylene,
It has been proposed that an acrylic resin-based material or an adhesive material containing various rubber or elastomer components such as polyvinyl ether and polyvinyl isobutyl ether as a main component is provided.

Such a coating film protective film for automobiles is
Although it is peeled off from the coated surface immediately before reaching the consumer's hand, the film is stretched or torn at this time, and there is a problem that the peeling work is very difficult and takes time.

In Japanese Patent Laid-Open No. 6-73352, 2 × 10 ^{5 to} 7 × 10 ⁵ dyne / cm at 60 ° C.
A rubber-based pressure-sensitive adhesive layer having a dynamic elastic modulus of ² is provided as a supporting base material, and in particular, a rubber-based pressure-sensitive adhesive compounded with silicone oil or an acrylic polymer having a weight average molecular weight of 1,000 to 50,000. By providing layers,
It is proposed that a coating film protective film having an excellent balance between adhesion protection and peeling workability can be obtained. However,
Even if the dynamic elastic modulus of the pressure-sensitive adhesive layer is adjusted within the above range, the above-mentioned problems such as elongation and tearing of the film at the time of peeling cannot be eliminated.

[0008]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an automotive coating protective film having improved properties. The present invention also exhibits stable adherence at the time of protection purposes such as transportation or storage of an automobile and does not cause problems such as peeling, but at the time of peeling work, peels easily and with good workability. An object is to provide a coating film protective film for automobiles which is possible.

[0009]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that in an automobile coating film protective film comprising a film substrate and a pressure-sensitive adhesive layer, the breaking strength of the protective film. When the ratio of the peeling strength to the peeling strength is in a specific ratio, the present invention has been found out that while the stable adherence is exhibited, the peeling work can be easily performed.

That is, the present invention for solving the above problems is
An automobile coating film protective film comprising a film substrate and a pressure-sensitive adhesive layer is characterized in that the ratio of breaking strength to peeling strength of the protective film is 10 or more and 50 or less.

In the coating film protective film for automobiles of the present invention, it is further preferable that the film substrate is made of polyethylene and polypropylene, and the content of polyethylene is 20% by weight or more and 35% by weight or less.

In the coating film protective film for automobiles of the present invention, it is also preferable that the pressure-sensitive adhesive layer contains polyisobutylene as a pressure-sensitive adhesive.

The coating film protective film for automobiles of the present invention also has a breaking strength of 40 N / 25 mm or more and 50 N / 2.
It is preferably 5 mm or less.

The coating film protective film for automobiles of the present invention also has a peeling strength of 1 N / 25 mm or more and 5 N /
It is preferably 25 mm or less.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail based on embodiments. FIG. 1 is a schematic cross-sectional view showing a configuration of one embodiment of a coating film protective film for an automobile according to the present invention in a use state.

As shown in FIG. 1, an automobile coating film protective film 1 of the present invention has a film base material 2 and an adhesive layer 3 formed on one surface side of the film base material 2. Therefore, the ratio of the breaking strength and the peeling strength of the protective film 1 (breaking strength / peeling strength) is 10 or more and 50 or less, more preferably 20 or more and 50 or less.

Here, if the ratio of the breaking strength to the peeling strength is less than 10, the adhesion of the protective film to the coated surface becomes too high, and it becomes extremely difficult to peel off the film. On the other hand, if the ratio of the breaking strength to the peeling strength exceeds 50, the adhesive strength to the painted surface becomes too low, and the protection is provided during transportation by ship, trailer, freight car, or during indoor or outdoor storage. There is a high possibility that the film will peel off and the desired coating surface protection cannot be achieved. Therefore, by keeping the ratio of the breaking strength and the peeling strength of the protective film within the predetermined range of 10 or more and 50 or less, stable adherence is exhibited for the purpose of protection such as transportation or storage of the automobile. Thus, the coating film protective film for an automobile can be peeled easily and with good workability at the time of peeling work, while not causing problems such as peeling.

The polymer constituting the film base material 2 in the coating film protective film for automobiles of the present invention is not particularly limited, and examples thereof include polyolefin, polyester, polyamide, polystyrene, polyurethane, polycarbonate, polyvinyl chloride and poly. Vinylidene chloride, polyacrylic acid ester, ethylene-vinyl acetate copolymer, styrene-butadiene copolymer, vinyl chloride-
Acrylic ester copolymer, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, acrylonitrile-
Various plastics or elastomers such as acrylic acid ester copolymers, fluorine-containing polymers, and silicone-based polymers or silicon-containing polymers can be used alone or as a mixture of a plurality of them, and of these, polyolefin is preferable.

As the polyolefin, homopolymers or copolymers of α-olefins such as ethylene, propylene and 1-butene, further copolymers of such α-olefins with other vinyl monomers copolymerizable with them, and further, these A mixture is included. Among such polyolefins, those which are most preferably made of polyethylene and polypropylene and have a polyethylene content of 20% by weight or more and 35% by weight or less. In such a polyethylene-polypropylene mixture,
If the polyethylene content is below 20% by weight,
The film base material becomes too hard, the followability deteriorates, and the laminating workability deteriorates. On the other hand, when the polyethylene content exceeds 35% by weight, the film base material becomes too soft and stretches, and the peeling work becomes difficult. It will be difficult. The film made of the polyethylene-polypropylene mixture is preferably extruded by the T-die method.

The film thickness of the film base material depends on the material constituting the film base material and is not generally defined, but is typically about 30 to 50 μm. If the film base material is extremely thin than the above range, the breaking strength of the film is lowered, and it tends to be torn during the peeling work, while the film base material is extremely thicker than the above range. Becomes too hard, the followability deteriorates, and the workability of application deteriorates.

In the film substrate, if necessary,
You may mix | blend various additives, such as an ultraviolet absorber, an antioxidant, a coloring agent, a lubricant, an antistatic agent, and a plasticizer.

As the ultraviolet absorber, various ones such as salicylic acid derivative, benzophenone type, benzotriazole type, hindered amine type and diphenyl acrylate type can be used. Among them, benzotriazole type is preferable. 2- (2'-hydroxy-5'-methylphenyl) benzotriazole,
2- (2'-hydroxy-3-t-butyl-5'-methylphenyl) -5-chlorobenzotriazole, alkylated hydroxyphenylbenzotriazole, 2- (2
′ -Hydroxy-3 ′, 5′-di-t-butylphenyl) -5-chlorobenzotriazole, 2- (3 ′, 5
Examples include ′ -alkyl-2′-hydroxyphenyl) benzotriazole and the like. The amount of these ultraviolet absorbers added is appropriately 0 to 5 parts by weight, preferably 0.1 to 1 part by weight, based on 100 parts by weight of the polymer.

As the antioxidant, various types such as phenol type, sulfide type, phosphite type amine type can be used. Specifically, for example, as a phenol type, 2,6-di-t-butyl-4-
Methylphenol, 2,2'-methylenebis (4-methyl-6-t-butylphenol), 4,4'-butylidenebis (3-methyl-6-t-butylphenol),
4,4'-thiobis (3-methyl-6-t-butylphenol), 2,2'-thiobis (4-methyl-6-t-)
Butylphenol) and the like, sulfide-based ones include dilaurylthiodipropionate, distearylthiopropionate, and the like, and phosphite-based ones include tridecylphosphite, diphenyldecylphosphite, triphenyl. Examples thereof include phosphite and trinonylphenyl phosphite. Of these, 2,6-di-t-butyl-4-methylphenol and the like are preferable. The amount of these antioxidants added is appropriately 0 to 1 part by weight, preferably 0.01 to 0.1 part by weight, based on 100 parts by weight of the polymer.

As the colorant, inorganic or organic pigments or dyes of various colors can be used alone or in combination of two or more kinds, and inorganic pigments are preferable from the viewpoint of weather resistance and non-migration property. Examples of black pigments include carbon black, copper oxide, manganese dioxide, and aniline black, examples of white pigments include titanium oxide, zinc white, antimony white, and zinc sulfide, and examples of extender pigments include barite. Powder, barium carbonate, clay, silica, white carbon, talc, alumina white and the like can be exemplified, and as chromatic colors, yellow pigments include yellow lead, zinc yellow, cadmium yellow, yellow iron oxide, mineral fast yellow, Nickel Titanium Yellow, Quinoline Yellow Lake, Permanent Yellow N
CG, Navels Yellow, Naphthol Yellow S, Bunzer Yellow G, Benzidine Yellow G, etc. are orange pigments such as red yellow lead, molybdenum orange, permanent orange GTR, pyrazolone orange, vulcan orange, benzidine orange G, etc. Examples include red iron oxide, cadmium red, red lead, permanent red, resole red, pyrazolone red, brilliant carmine 6B, rhodamine lake B, and alizarin lake, and purple pigments include manganese purple, fast violet red, and methyl violet lake. , As blue pigment, dark blue, cobalt blue, alkali blue lake, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, fast sky blue, etc. are green. The pigment chrome green, chromium oxide, pigment green B, mica light green lake, and final yellow green G can be exemplified. Examples of dyes include nigrosine, merylene blue, rose bengal, quinoline yellow, and ultramarine blue. Of course, usable colorants are not limited to those exemplified above.

Of these coloring agents, it is of course possible to use chromatic ones, but achromatic ones are preferable in view of economic efficiency. In addition, black pigments and the like having low lightness are excellent in terms of hiding and blocking properties, but the heat increase due to light absorption is large, and depending on the weather conditions, the temperature may rise to, for example, 80 ° C or higher. Since there is a high possibility of adversely affecting the agent layer, white pigments,
It is desirable to mainly use a high-brightness pigment such as a part of an extender pigment, and it is particularly desirable to adjust the film substrate to a white pigment having a Munsell color system of N7 or more. The addition amount of the colorant depends on the type of the colorant used, the addition amount of the ultraviolet absorber as described above, etc., and therefore cannot be unconditionally specified, but the ultraviolet transmission amount of the film substrate is from 190 to 90. 1% or less in the range of 370 nm,
It is desirable to add it so that it is preferably 0.1% or less.

On the other hand, as the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 3, polyisobutylene and styrene-isoprene-styrene block copolymers can be used as long as the pressure-sensitive adhesive strength satisfying the desired ratio of breaking strength and peeling strength can be imparted. Polymers, styrene-butadiene-styrene block copolymers, styrene-ethylene-styrene copolymers, rubber-based adhesives such as ethylene propylene rubber, ethylene-vinyl acetate copolymers, ethylene-ethyl acrylate copolymers, ethylene -Ethylene-based adhesives such as vinyl acetate-methacrylic acid copolymer, ethylene-vinyl acetate copolymer partially saponified product, (meth) acrylonitrile containing (meth) acrylic acid alkyl ester as a main component,
Acrylic pressure-sensitive adhesives obtained by copolymerizing monomers such as (meth) acrylic acid and styrene can be used alone or in combination, and of these, rubber-based pressure-sensitive adhesives are preferable, and polyisobutylene is particularly preferable.

Polyisobutylene has a relatively small viscoelastic behavior in the surface temperature range of the actual vehicle coating surface range of about -40 ° C. to about 90 ° C., has a small effect on the coating film surface, and has an adhesive force. Since it is less deteriorated with time, it is most suitable as an adhesive for the coating film protective film of the present invention. As the polyisobutylene, those having a viscosity average molecular weight of about 10,000 to 1,500,000 can be used, but in order to have a desired adhesive force and good releasability in a good balance, for example, a viscosity average molecular weight of 1,000,000. A mixture of a high molecular weight substance having a viscosity average molecular weight of about 10,000 to 100,000 and a low molecular weight substance having a viscosity average molecular weight of about 10,000 to 100,000 (for example, a mixture having a weight ratio of 95/5 to 50/50) can be employed. Of course, the present invention is not limited to such an embodiment, and a viscosity average molecular weight is used alone, and further, various types such as those having an adhesive force adjusted by blending a tackifier, an inorganic filler and the like as described below. Can be the embodiment of

On the other hand, the acrylic adhesive and the ethylene adhesive have a large change in adhesive strength over time, and especially when the temperature rises due to outdoor transfer or when the adhesive is left for a long time, peeling work is required. Since it becomes difficult, it is desirable to adjust the adhesive strength by adding an inorganic filler, an ultraviolet absorber or the like as described below. Acrylic adhesive is
Since it has a polar group, it may cause problems such as fogging on the surface of the coating film depending on the type of paint used for coating automobile bodies, especially when applied to coating cars such as melamine-acrylic paints. In, it's not very desirable.

In the composition constituting the pressure-sensitive adhesive layer, in addition to such a pressure-sensitive adhesive, additives such as a tackifier, an inorganic filler, a softening agent, an antiaging agent, an ultraviolet absorber and a colorant are added. It can be blended as needed.

As the tackifier, polymerized rosin, rosin acid glycol ester, rosin acid glycerin ester,
Although rosin acid esters such as rosin acid pentaerythritol ester and hydrogenated products thereof, rosin acid and derivatives thereof such as rosin acid phenol alkylphenol formaldehyde resin and the like, terpene resin, phenol resin, coumarone indene resin and the like can be used. Preferred are rosin acid esters and hydrogenated products thereof. Further, the addition amount of these tackifiers is appropriately 0 to 10 parts by weight, more preferably 2 to 5 parts by weight, relative to 100 parts by weight of the adhesive.

As the inorganic filler, talc, diatomaceous earth, silicon oxide kaolin, aluminum oxide, zinc oxide,
Examples thereof include caldium carbonate, magnesium carbonate, calcium sulfate, barium sulfate and the like. The addition amount of these inorganic fillers is about 0 to 10 parts by weight with respect to 100 parts by weight of the adhesive. Moreover, as the ultraviolet absorber and the colorant, the same ones as described above can be used.

The thickness of the pressure-sensitive adhesive layer depends on the constitution of the pressure-sensitive adhesive composition and the like, and is not generally defined, but is typically about 5 to 15 μm. If the pressure-sensitive adhesive layer is extremely thinner than the above range, there is a possibility that uniform and stable pressure-sensitive adhesive force may not be obtained, while,
If the thickness is extremely thicker than the above range, interlayer peeling is likely to occur between the film base material and the pressure-sensitive adhesive layer, and there is a risk that adhesive residue may occur during the peeling operation.

The method of forming the pressure-sensitive adhesive layer 3 on one surface of the film base material 2 is not particularly limited, and a method of dissolving the pressure-sensitive adhesive composition in a solvent and applying it to the film base material,
A method of heating and melting a pressure-sensitive adhesive composition to apply it to a film substrate, a method of transferring a pressure-sensitive adhesive layer formed on a release paper or a separator, and further a polymer composition and a pressure-sensitive adhesive layer constituting the film substrate. Any method such as a method in which each of the constituent pressure-sensitive adhesive compositions is melted by heating and co-melt-extruded into a film can be adopted.

Further, in the coating film protective film for automobiles according to the present invention, in order to improve the adhesion force (anchoring force) between the film base material 2 and the pressure-sensitive adhesive layer 3, the surface of the film base material 2 is subjected to corona discharge treatment. It is also possible to form the pressure-sensitive adhesive layer after subjecting it to an oxidation treatment or the like, or after coating with a primer such as a polyurethane compound, a composition containing chlorinated polypropylene and polyisobutylene and / or butyl rubber, etc. .

The surface of the pressure-sensitive adhesive layer of the coating film for automotive coating thus obtained is used until it is used.
A suitable release paper or separator is attached and protected.

Further, the coating film protective film for automobiles of the present invention thus obtained has a breaking strength of 4
It is desirable to have a value in the range from 0 N / 25 mm to 50 N / 25 mm. When the breaking strength is less than 40 N / 25 mm, the film becomes too soft and stretches, and peeling work is likely to be difficult. On the other hand, the breaking strength is too hard, the followability becomes poor, and sticking This is because the workability is likely to decrease. Further, the coating film protective film for automobiles of the present invention preferably has a peeling strength in the range of 1 N / 25 mm or more and 5 N / 25 mm or less. Peeling strength is 1N / 2
If it is less than 5 mm, the adhesive force to the coated surface becomes too low, and the protective film will peel off during transportation by ship, trailer, freight car, etc. or during indoor or outdoor storage, and the desired coated surface can be protected. There is a high possibility that it will disappear,
On the other hand, if the peeling strength exceeds 5 N / 25 mm, the adhesive strength to the coated surface becomes too high, and it is likely that it will be difficult to peel off the film.

Incidentally, the "breaking strength" mentioned in the present invention.
Means that an automobile coating film protective film cut into a size of 25 mm × 100 mm is pulled at room temperature (20 ° C. ± 1 ° C.) and a pulling speed of 300 mm / min, and the load when breaking is measured. The "peeling strength" referred to in the present invention refers to the obtained value and is 25 mm x 100 m.
After attaching an automobile coating film protective film cut into a size of m on the coated surface, 1 hour later, at room temperature (20 ° C ±
1 ° C.), and a value obtained by measuring the adhesive force when peeling in the direction of 180 ° under a peeling speed of 300 mm / min.

[0038]

EXAMPLES The present invention will be described in more detail below with reference to examples. Example 1 Polypropylene / polyethylene (weight ratio: 80/20)
95% of polyisobutylene having a viscosity average molecular weight of 1.2 million against a film substrate made of a blended product and having a thickness of 35 μm
A heptane solution (20 wt% concentration) of a rubber-based pressure-sensitive adhesive composed of a mixture of 5 parts by weight of polyisobutylene having a viscosity average molecular weight of 35,000 and 5 parts by weight, and dried at 100 ° C. for 3 minutes to give a thickness of 15 μm. A coating film protective film for automobiles having the pressure-sensitive adhesive layer was obtained.

On the other hand, a 70 × 150 mm size zinc steel test piece was pretreated with Granodine DP4000 (manufactured by Nippon Paint) and electrodeposited by U-100 (manufactured by Nippon Paint) at 180 ° C. It was baked and dried for 20 minutes. Next, OP-41 (manufactured by Nippon Paint Co., Ltd.) was applied as an intermediate coating, and baked and dried at 140 ° C. for 20 minutes. The intermediate coating film thickness was 35 μm. Subsequently, OG-75 white (manufactured by Nippon Paint Co., Ltd.) was applied as a top coat, and baked and dried at 140 ° C. for 20 minutes. The top coating film thickness was 35 μm. Thus, a top coated plate was obtained.

Then, the protective film produced as described above was cut into a size of 25 mm × 100 mm, and a 5 Kg rubber roller was reciprocated once against this top-coated plate at room temperature (20 ° C. ± 1 ° C.) to press it. The obtained samples were evaluated for peeling strength, breaking strength and peeling workability as described below. The results obtained are shown in Table 1.

Example 2 The heptane solution of the rubber adhesive of Example 1 was changed to a mixture of 75 parts by weight of polyisobutylene having a viscosity average molecular weight of 1.2 million and 25 parts by weight of polyisobutylene having a viscosity average molecular weight of 35,000. In the same manner as in Example 1, a sample was prepared and evaluated. The results obtained are shown in Table 1.

Example 3 The heptane solution of the rubber adhesive of Example 1 was changed to a mixture of 50 parts by weight of polyisobutylene having a viscosity average molecular weight of 1.2 million and 25 parts by weight of polyisobutylene having a viscosity average molecular weight of 35,000. In the same manner as in Example 1, a sample was prepared and evaluated. The results obtained are shown in Table 1.

Example 4 A sample was prepared and evaluated in the same manner as in Example 1 except that the film substrate of Example 1 was changed to a polypropylene / polyethylene (weight ratio: 70/30) blend. Was done. The results obtained are shown in Table 1.

Example 5 A sample was prepared and evaluated in the same manner as in Example 2 except that the film substrate of Example 2 was changed to a polypropylene / polyethylene (weight ratio: 70/30) blend. Was done. The results obtained are shown in Table 1.

Example 6 A sample was prepared and evaluated in the same manner as in Example 1 except that the film substrate of Example 1 was changed to a polypropylene / polyethylene (weight ratio: 65/35) blend. Was done. The results obtained are shown in Table 1.

Example 7 A sample was prepared and evaluated in the same manner as in Example 2 except that the film substrate of Example 2 was changed to a polypropylene / polyethylene (weight ratio: 65/35) blend. Was done. The results obtained are shown in Table 1.

Comparative Example 1 A sample was prepared and evaluated in the same manner as in Example 1 except that the film substrate of Example 1 was changed to a polypropylene / polyethylene (weight ratio: 85/15) blend. Was done. The results obtained are shown in Table 1.

Comparative Example 2 A heptane solution of the rubber adhesive of Example 1 was changed to a mixture of 25 parts by weight of polyisobutylene having a viscosity average molecular weight of 1.2 million and 75 parts by weight of polyisobutylene having a viscosity average molecular weight of 35,000. In the same manner as in Example 1, a sample was prepared and evaluated. The results obtained are shown in Table 1.

Comparative Example 3 A sample was prepared in the same manner as in Example 1 except that the heptane solution of the rubber-based pressure-sensitive adhesive of Example 1 was changed to 100 parts by weight of polyisobutylene having a viscosity average molecular weight of 1.2 million. , The evaluation was performed. The results obtained are shown in Table 1.

<Evaluation Method> Peeling strength After the automobile coating film protective films shown in Examples and Comparative Examples were attached to the top coating plate, 1 hour later,
At room temperature (20 ° C. ± 1 ° C.) and a peeling speed of 300 mm / min, the adhesive strength when peeling in the direction of 180 ° was measured.

Breaking strength Each of the automobile coating film protective films shown in Examples and Comparative Examples was cut into a size of 25 mm × 100 mm, and the conditions were room temperature (20 ° C. ± 1 ° C.) and a pulling speed of 300 mm / min. The load at the time of pulling and breaking was measured.

Peeling workability A sample prepared by sticking each of the automobile coating protective films shown in Examples and Comparative Examples on a top-coated plate was exposed to the outdoors (Okinawa area) for 3 months and then left at room temperature (20 hours) for 24 hours. ℃ ± 1 ℃)
After being left at room temperature, the coating film for automobile coating film of each sample was peeled off and the ease of peeling was evaluated. In addition, evaluation is the following 3
According to the criteria of stages. ◯: Can be easily peeled, Δ: Can be peeled, ×: It is difficult to peel due to stretching or tearing.

[0053]

[Table 1]

[0054]

As described above, according to the present invention, a protective film for an automobile coating film comprising a film substrate and a pressure-sensitive adhesive layer has a ratio of breaking strength to peeling strength of 10 or more and 50 or less. Therefore, while exhibiting stable adherence, the protective film maintains sufficient rigidity, so that the peeling work can be easily performed. Therefore, by sticking the coating film protective film for an automobile according to the present invention on the coating film surface of a finished car or a coated part, these products can be delivered to the hands of consumers.
When transported by ship, trailer, freight car, etc., or temporarily stored indoors or outdoors, the surface of the coating film is stably protected from deterioration factors such as rain (acid rain), iron powder, dust, salts, and sun rays. In addition, it is possible to reduce the labor required for the peeling work at a store or the like.

Further, in the coating film protective film for automobiles of the present invention, the film base material is made of polyethylene and polypropylene, and the polyethylene content is 20% by weight.
When the amount is 35% by weight or more, the workability of attaching and peeling the protective film is improved.

In the coating film protective film for automobiles of the present invention, when the pressure-sensitive adhesive layer contains polyisobutylene as a pressure-sensitive adhesive, better adherence can be obtained stably over time, and the coating film surface There is no risk of adverse chemical or physical effects.

The breaking strength of the automobile coating protective film of the present invention is 40 N / 25 mm or more and 50 N / 25 mm.
When it is below, the workability of attaching and peeling the protective film will be better.

In the coating film protective film for automobiles of the present invention, the peeling strength is 1 N / 25 mm or more and 5 N / 25 m.
When it is m or less, better adherence can be obtained, and problems such as peeling will not occur when protecting the coating film, while peeling can be performed more easily and with good workability.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a configuration of an embodiment of an automobile coating film protective film according to the present invention in a use state.

[Explanation of symbols]

1 Automotive coating protective film, 2 film substrate, 3 adhesive layer, 4 Body surface coating film.

─────────────────────────────────────────────────── --- Continuation of the front page (56) Reference JP-A-56-55252 (JP, A) JP-A-7-188620 (JP, A) JP-A-7-188625 (JP, A) JP-A-8- 143839 (JP, A) JP-A-8-14380 (JP, A) JP-A-8-73820 (JP, A) JP-A-50-52141 (JP, A) JP-A-4-106175 (JP, A) JP-A-6-128540 (JP, A) JP-A-6-328640 (JP, A) JP-A-7-117195 (JP, A) JP-A-9-31426 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B32B 1/00-35/00 C08J ^7/ 00-7/04

Claims (5)

(57) [Claims] 1. A coating film for automobiles comprising a film substrate and a pressure-sensitive adhesive layer, wherein the ratio of breaking strength to peeling strength of the protective film is 10 or more and 50 or less. Protective film. 2. The coating film protective film for automobiles according to claim 1, wherein the film substrate is made of polyethylene and polypropylene, and the polyethylene content is 20% by weight or more and 35% by weight or less. 3. The pressure-sensitive adhesive layer contains polyisobutylene as a pressure-sensitive adhesive, which is characterized in that:
The coating film protective film for automobiles according to. 4. A breaking strength of 40 N / 25 mm or more and 50 N
/ 25 mm or less, The coating film protective film for automobiles according to any one of claims 1 to 3. 5. A peeling strength of 1 N / 25 mm or more 5
It is N / 25mm or less, Claims 1-4 characterized by the above-mentioned.
The coating film protective film for automobiles according to any one of 1.