JP7545792B2 - Base film for attaching to car body - Google Patents

Description

The present invention mainly relates to a base film for application to vehicle bodies.

Films are sometimes applied to the bodies of automobiles, buses, trains, etc. for advertising and decoration, in addition to protecting the body. Such films applied to the bodies of automobiles, buses, trains, etc. (films for application to the body) generally consist of a base film for application to the body and an adhesive. A variety of resin films are used for the base film for application to the body, and not only single-layer but also multi-layered films are used. Furthermore, a surface treatment agent layer may be provided to impart weather resistance and antifouling properties to the base film for application to the body. A commonly used construction method is to apply the film for application to the body by adhering the adhesive layer of the film for application to the body to the body, which is the adherend.

Because films for application to vehicle bodies are applied to the vehicle body through application, the base film for application to vehicle bodies is also required to be easy to apply (applicability) and to be able to conform to the shape of the vehicle body. Furthermore, because the bodies of automobiles, buses, trains, and other vehicles are used outdoors, the base film for application to vehicle bodies is required to be weather resistant. With regard to weather resistance, it may be necessary to prevent changes in appearance when used outdoors, in particular yellowing, where the film turns yellow.

Patent document 1 discloses a protective sheet that is a surface treatment region that includes a solid plastic film having an upper surface and a lower surface, and one or more components applied to the upper surface of the film as a coating composition, and that can be suitably used for automobile bodies.

Special table 2013-533131 publication

When polyvinyl chloride resin is used as a base film for application to a vehicle body, it needs to have a suitable degree of flexibility in terms of ease of application when applied to the vehicle body and conformability to the vehicle body. Therefore, plasticizers are added to polyvinyl chloride resins to impart flexibility, but there is a concern that the plasticizer will migrate to other layers such as the adhesive. For example, if the film for application to a vehicle body has an adhesive layer, there is a risk of the plasticizer migrating to the adhesive layer and causing problems such as a decrease in adhesive strength. In addition, if the film for application to a vehicle body has other resin layers, there is a risk of the plasticizer migrating to the other resin layers and causing problems such as discoloration and softening.

The present invention therefore aims to provide a substrate film for application to a vehicle body that has an appropriate degree of flexibility and excellent workability due to the addition of a plasticizer to the polyvinyl chloride resin used as the substrate film for application to a vehicle body, and that reduces problems caused by the migration of the plasticizer to other layers.

The means used in the present invention to solve the above-mentioned problems is to provide a substrate film for application to a vehicle body, which contains 20 to 40 parts by weight of a polyester plasticizer having a viscosity of 100 mPa·s/25° C. to 3500 mPa·s/25° C., 0.1 to 10 parts by weight of an ultraviolet absorber, and 0.1 to 10 parts by weight of a hindered amine light stabilizer, relative to 100 parts by weight of a polyvinyl chloride resin, and does not contain an acrylic resin. In addition, a substrate film for application to a vehicle body having a plasticizer migration rate of less than 3% in a plasticizer migration test is preferable.
Test Method
A substrate film for application to a vehicle body having a diameter of 70 mm is prepared, and the weight of the substrate film for application to a vehicle body before the test is measured. The substrate film for application to a vehicle body whose weight has been measured is sandwiched between two polypropylene sheets having a diameter of 70 mm and a thickness of 750 μm, and placed in a high-temperature chamber set at 60° C. for 24 hours, and the weight of the substrate film for application to a vehicle body after cooling is measured.
"Calculation method for plasticizer migration rate"
(Weight of the base film for application to the vehicle body before the test [g] - Mass of the base film for application to the vehicle body after the test [g]) / Weight of the base film for application to the vehicle body before the test [g] x 100% = Plasticizer migration rate [%]
Furthermore, the film may be a substrate film for application to a vehicle body, in which in an accelerated weather resistance test using a water-cooled metal halide lamp, the difference in yellowness between before and after 304 hours of the accelerated weather resistance test (ΔYI) is less than 30. The film may also be a substrate film for application to a vehicle body used in a film for application to a vehicle body having a pressure-sensitive adhesive layer, or a film for application to a vehicle body that is a film for protecting the vehicle body of an automobile.

According to the present invention, by adding a plasticizer to a polyvinyl chloride resin, it is possible to provide a base film for application to a vehicle body that has appropriate flexibility, excellent workability as a film for application to a vehicle body, and reduces defects caused by migration of the plasticizer to other layers.

The present invention will be described in detail below.
The polyvinyl chloride resin used in the present invention may be polyvinyl chloride, ethylene-vinyl chloride, propylene-vinyl chloride copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinylidene chloride copolymer, or the like.

The average degree of polymerization of polyvinyl chloride resin is not particularly limited as long as it is substantially moldable, but an average degree of polymerization in the range of 500 to 2000 is preferable, and an average degree of polymerization in the range of 700 to 1300 is even more preferable. If the average degree of polymerization is less than 500, the viscosity when melted is low and processing is difficult, and if the average degree of polymerization is more than 2000, the viscosity when melted is high and processing may be difficult.

The plasticizers used in the present invention are added for the purpose of softening polyvinyl chloride resins and improving their processability, and include phthalic acid plasticizers such as DOP (di-2-ethylhexyl phthalate), DINP (diisononyl phthalate), DIDP (diisodecyl phthalate), and DOTP (dioctyl terephthalate), polyester plasticizers with a molecular weight of 800 to 8,000, which have a basic structure of polycondensation of dibasic acid and glycol and are terminated at both ends with monobasic acid or monohydric alcohol, and DOA (di-2-ethylhexyl adipate). , adipic acid ester plasticizers such as DIDA (diisodecyl adipate), sebacate acid ester plasticizers such as DOS (di-2-ethylhexyl sebacate), azelaate acid ester plasticizers such as DOZ (di-2-ethylhexyl azelate), aliphatic dibasic acid ester plasticizers, phosphate ester plasticizers such as tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, tris(isopropylated phenyl) phosphate, tris(dichloropropyl) phosphate, and sulfonate ester plasticizers can be used.

The amount of polyester plasticizer added is preferably 5 to 50 parts by weight per 100 parts by weight of polyvinyl chloride resin. If the amount of plasticizer added exceeds 50 parts by weight, bleeding of the plasticizer from the base film for application to the vehicle body or blocking may occur. If the amount is less than 10 parts by weight, processing may become difficult. The amount of plasticizer added is more preferably 10 to 40 parts by weight, which is excellent in that it has moderate flexibility and extensibility as well as no stickiness or plate-out during processing.

Here, adipic acid-based polyester plasticizers are preferably used because of their excellent weather resistance. Adipic acid-based polyester plasticizers are polyesters made of adipic acid or an adipic acid derivative and alcohol, and examples thereof include polyethylene adipate, dioctyl polyadipate, diisooctyl polyadipate, diisodecyl polyadipate, etc. Adipic acid-based polyester plasticizers are also excellent in that they are less likely to migrate from the film, and it is preferable to use an adipic acid-based polyester plasticizer when a pressure-sensitive adhesive layer or other resin layer is laminated on a base film for application to a vehicle body.
In addition, a polyester plasticizer having a viscosity of about 100 mPa·s/25°C to 3500 mPa·s/25°C can be used. The viscosity is preferably 120 mPa·s/25°C to 3000 mPa·s/25°C, more preferably 150 mPa·s/25°C to 2000 mPa·s/25°C. If the viscosity of the polyester plasticizer exceeds about 5000 mPa·s/25°C, the fluidity is low and it becomes difficult to handle during processing. If the viscosity is 3000 mPa·s/25°C or less, the fluidity is improved and it becomes easy to handle, and if it is 2000 mPa·s/25°C or less, it is preferable because it can be handled in the same way as phthalic acid plasticizers such as DOP.

In the present invention, it is preferable to use a perchlorate. Examples of perchlorate include sodium perchlorate, potassium perchlorate, and ammonium perchlorate. The amount of addition is preferably 0.01 to 2 parts by weight, more preferably 0.05 to 1 part by weight, and even more preferably 0.1 to 0.5 parts by weight. If the amount is less than 0.01 parts by weight, sufficient weather resistance cannot be obtained, and if the amount is more than 2 parts by weight, there is a risk of a decrease in thermal stability during processing, plate-out, and bleed-out after processing.
Here, perchlorates are expected to function as stabilizers when additives are added to polyvinyl chloride resins and processed into films. Meanwhile, the inventors have found that perchlorates reduce yellowing of substrate films for application to vehicle bodies in tests using a weather resistance tester for substrate films for application to vehicle bodies, although the mechanism is unclear.

The yellowing of the base film for application to the vehicle body can be evaluated by measuring the yellowness index (YI) using a spectrophotometer or the like and calculating the change in the yellowness index. If the change in yellowness index is ΔYI, then ΔYI is calculated by subtracting the initial yellowness index (YI) before discoloration from the yellowness index (YI) after discoloration. Here, a weather resistance tester is often used to evaluate the yellowing of the base film for application to the vehicle body. Thus, the yellowing of the film before and after the weather resistance test can be evaluated by calculating ΔYI using the following formula.
"ΔYI" = "Yellowness (YI) measured after a weather resistance test for a specified period of time" - "Yellowness (YI) measured before a weather resistance test"
The measurement method can be according to Plastics-Determination of Yellowness and Discoloration (JIS K7373:2006).

The ultraviolet absorbing agent used in the present invention is added for the purpose of preventing deterioration of the base film to be applied to the vehicle body. It is believed that the main function of the ultraviolet absorbing agent is to absorb ultraviolet rays and convert them into heat energy or long light waves.
Examples of such an absorbent include those that are conventionally blended into polyvinyl chloride resins, such as benzophenone-based, benzotriazole-based, triazine-based, salicylic acid ester-based, cyanoacrylate-based, etc. It is preferable to use a benzotriazole-based ultraviolet absorber, since it has excellent ultraviolet absorbing ability in the wavelength range (320 nm to 400 nm) that is thought to be involved in the yellowing due to deterioration of the substrate film for application to the vehicle body, and the initial color tone of the obtained substrate film for application to the vehicle body is less yellowish. Specific examples of the benzotriazole-based ultraviolet absorber include 2-(2'-hydroxy-5'-methylphenyl)-benzotriazole, 2-(2'-hydroxy-5'-tert-butylphenyl)-benzotriazole, 2-(2'-hydroxy-3'-methyl-5'-tert-butylphenyl)-benzotriazole;2-(2'-hydroxy-5'-cyclohexylphenyl)-benzotriazole;2-(2'-hydroxy-3',5'-dimethylphenyl)-benzotriazole,2-(2'-hydroxy-5'-tert-butylphenyl)-5-chloro-benzotriazole,2-(2'-hydroxy-5-tert-octylphenyl)-2H-benzotriazole; nyl)-2H-benzotriazole, 2-(3',5'-di-tert-butyl-2'-hydroxyphenyl)-5-chlorobenzotriazole, 2-(3'-tert-butyl-5'-methyl-butyl-2'hydroxyphenyl)-5-chlorobenzotriazole, 2-(3',5'-di-tert-amyl-2'-hydroxyphenyl)benzotriazole, 2-(3',5'-bis(α,α-dimethylbenzyl)-2'-hydroxyphenyl)benzotriazole, 2-(3'-tert-butyl-2'-hydroxy-5'-(2-octyloxycarbonylethyl)phenyl)benzotriazole, 2,2'-methylene-bis[4-(1,1,3,3-tetramethylbutyl)-6-benzotriazol-2-ylphenone 2-[2'-hydroxy-3'-(α,α-dimethylbenzyl)-5'-(1,1,3,3-tetramethyl-butyl)phenyl]benzotriazole, 5-trifluoromethyl-2-(2-hydroxy-3-α-cumyl-5-tert-octylphenyl)-2H-benzotriazole, 2-(2'-hydroxy-5'-(2-hydroxyethyl)phenyl)benzotriazole, 2-(2'-hydroxy-5'-(2-methacryloyloxyethyl)phenyl)benzotriazole, 2-(3'-tert-butyl-5'-methyl-2'-hydroxyphenyl)-5-chloro-benzotriazole, 2-(3'-sec-butyl-5'-tert-butyl-2'-hydroxyphenyl)-benzotriazole, 2- (3',5'-di-tert-butyl-2'-hydroxyphenyl)-benzotriazole, 2-(5'-tert-octyl-2'-hydroxyphenyl)-benzotriazole, 2-(3'-dodecyl-5'-methyl-2'-hydroxyphenyl)-benzotriazole;, 2-(3'-tert-butyl-5'-(2-octyloxycarbonylethyl)-2'-hydroxyphenyl)-5-chlorobenzotriazole, 2-(5'-methyl-2'-hydroxyphenyl)-benzotriazole, 2-(5'-tert-butyl-2'-hydroxyphenyl)-benzotriazole, 2-(2'-hydroxy-3'-di-tert-butylphenyl)-benzotriazole, etc. are exemplified, but are not particularly limited thereto. In addition, these benzotriazole-based ultraviolet absorbers can be used alone or in combination of two or more kinds.

The amount of ultraviolet absorber added is 0.1 to 10 parts by weight per 100 parts by weight of polyvinyl chloride resin. 0.2 to 3 parts by weight is more preferable, and 0.3 to 2 parts by weight is even more preferable. If the amount is less than 0.1 part by weight, sufficient weather resistance cannot be obtained, and if the amount is more than 10 parts by weight, when the ultraviolet absorber is added to the polyvinyl chloride resin and processed, the ultraviolet absorber may plate out onto the metal roll of the processing machine, reducing processability, or the initial color tone of the obtained base film for application to the vehicle body may become yellowish or bleed out over time, which is not preferable.

The hindered amine light stabilizer used in the present invention is expected to have the function of capturing free radicals generated by ultraviolet light, etc. Furthermore, it is believed that the addition of a hindered amine light stabilizer to a polyvinyl chloride resin to which a plasticizer has been added reduces the deterioration of the plasticizer caused by ultraviolet light, which also contributes to the reduction of yellowing of the base film to be applied to the vehicle body.
Specific examples include 2,2,6,6-tetramethylpiperidyl-4-benzoate, bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(2,2,6,6-tetramethyl-4-piperidyl)oxalate, bis(2,2,6,6-tetramethyl-4-piperidyl)malonate, (2,2,6,6-tetramethyl-4-piperidyl)adipate, tris(2,2,6,6-tetramethyl-4-piperidyl)phosphite, tris(2,2,6,6-tetramethyl-4-piperidyl)phosphate ... tris(2,2,6,6-tetramethyl-4-piperidyl)benzene-1,3,5-tricarboxylate, tris(2,2,6,6-tetramethyl-4-piperidyl)triazine-2,4,6-tricarboxylate, tris(2,2,6,6-tetramethyl-4-piperidyl)nitrotriacetate, tris(2,2,6,6-tetramethyl-4-piperidyl)butane-1,2,3-tricarboxylate, 1,3,8-triaza-7,7,9,9-tetramethyl-3-n-octylspiro[ 4,5]decane-2,4-dione, 1,2,3,4-tetra(4-carbonyloxy-2,2,6,6-tetramethylpiperidyl)-butane, 1,3,8-triaza-7,7,9,9-tetramethyl-2,4-dioxo-spiro[4,5]decane, tri(4-acetoxy-2,2,6,6-tetramethylpiperidyl)amine, 4-acetoxy-2,2,6,6-tetramethylpiperidine, 4-stearoyloxy-2,2,6,6-tetramethylpiperidine, 4-benzyloxy-2,2,6,6-tetramethylpiperidine, benzyloxy-2,2,6,6-tetramethylpiperidine, 4-phenylcarbamoyloxy-2,2,6,6-tetramethylpiperidine, 4-p-toluenesulfonyloxy-2,2,6,6-tetramethylpiperidine, bis(2,2,6,6-tetramethyl-4-piperidyl)terephthalate, a mixed ester of 1,2,3,4-butanetetracarboxylic acid with 1,2,2,6,6-pentamethyl-4-piperidinol and 3,9-bis(2-hydroxy-1,1-dimethylethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane, etc. Furthermore, these light stabilizers can be used alone or in combination of two or more kinds.

The amount of hindered amine light stabilizer added is 0.1 to 10 parts by weight per 100 parts by weight of polyvinyl chloride resin. 0.2 to 3 parts by weight is more preferable, and 0.3 to 2 parts by weight is even more preferable. If it is less than 0.1 part by weight, sufficient weather resistance cannot be obtained, and if it is more than 10 parts by weight, the weather resistance improvement effect commensurate with the amount added cannot be obtained.

In the present invention, the use of a combination of an ultraviolet absorber and a hindered amine light stabilizer contributes to reducing yellowing of the base film to be applied to the vehicle body. Although the mechanism of this action is not clearly understood, it is believed that a synergistic effect is achieved by the separate action of the ultraviolet absorber, which absorbs ultraviolet light, and the hindered amine light stabilizer, which has the effect of capturing free radicals. It is presumed that this results in improved weather resistance, particularly reduced yellowing, compared to when only an ultraviolet absorber or hindered amine light stabilizer is used.

As the stabilizer, Ba-based, Ca-based, and Zn-based stabilizers can be used, and a combination of these, such as Ba/Zn-based composite stabilizers and Ca/Zn-based composite stabilizers, can be used. More specifically, Ba-based, Ca-based, and Zn-based metal soaps such as Ba stearate are preferably used. Furthermore, tin-based stabilizers, phosphites, epoxidized soybean oil, β-diketone, etc. may also be used.

If necessary, other additives that are generally added to resins, such as stabilizers, pigments, fillers, UV shielding agents, antistatic agents, flame retardants, thickeners, surfactants, fluorescent agents, crosslinking agents, and impact modifiers, may also be added.

The thickness of the base film for application to the vehicle body can be about 10 to 1000 μm, depending on the application. When used for printing, overlamination, lamination, tape, etc., 20 to 500 μm is preferable. Furthermore, the thinner the thickness, the greater the yellowing, and the effect of the thickness is particularly large when the base film for application to the vehicle body is transparent. Therefore, the thickness is preferably about 40 to 300 μm, and more preferably 50 to 200 μm.

For the mixing step in producing the base film for application to vehicle bodies, known equipment normally used for thermoplastic resins can be used. For example, a polyvinyl chloride resin composition in which a plasticizer, an ultraviolet absorber, a hindered amine light stabilizer, perchloric acid, etc. have been added to a polyvinyl chloride resin may be mixed uniformly using a high-speed mixer, a low-speed mixer, a Henschel mixer, etc., and melt-mixed using a batch-type kneading mixer, a Banbury mixer, a co-kneader, an extruder, etc., and immediately molded. Alternatively, after melt mixing, the mixture may be pelletized and then molded.

A sheet molding method can be used for the melt shaping process when manufacturing the base film for application to vehicle bodies. As the sheet molding method, in terms of the thickness accuracy of the obtained sheet, a calendar molding method or a roll molding method is preferable, and in terms of processing speed, a calendar molding method is also preferable. In addition, molding can be performed by a general sheet molding method. For example, an extrusion molding method, a press molding method, a blow molding method, etc. can be mentioned.

The present invention will be explained in detail below with reference to examples, but the present invention is not limited to these examples.

The ingredients used in the examples and comparative examples are as follows:
Polyvinyl chloride resin A: Polyvinyl chloride resin average degree of polymerization 1000
Plasticizer B-1: Adipic acid-based polyester plasticizer (viscosity: 600 mPa·s/25°C)
Plasticizer B-2: Adipic acid polyester plasticizer (viscosity: 150 mPa·s/25°C)
Plasticizer B-3: Adipic acid polyester plasticizer (viscosity: 500 mPa·s/25°C)
Plasticizer B-4: Adipic acid polyester plasticizer (viscosity: 1400 mPa·s/25°C)
Plasticizer B-5: Adipic acid polyester plasticizer (viscosity: 3000 mPa·s/25°C)
Plasticizer B-6: Adipic acid polyester plasticizer (viscosity: 4850 mPa·s/25°C)
Plasticizer B-7: Phthalic acid plasticizer DOP (viscosity: 57 mPa·s/25°C)
Plasticizer B-8: 2-ethylhexyl terephthalate DOTP (viscosity: 60 mPa·s/25°C)
Perchlorate C-1: Sodium perchlorate UV absorber D-1: Benzotriazole UV absorber (molecular weight: 323)
UV absorber D-2: Benzotriazole-based UV absorber (molecular weight: 225)
UV absorber D-3: Triazine-based UV absorber (molecular weight: 700)
Hindered amine light stabilizer E-1 (molecular weight: 481)
Hindered amine light stabilizer E-2 (molecular weight: approx. 2000)
Stabilizer F-1: Metal soap-based composite stabilizer

"Example 1"
Using the ingredients of Example 1 shown in the formulation column of Table 1, a base film for application to a vehicle body was molded under the molding conditions in the table, and the evaluation items shown in the table were evaluated by the following methods.
Other examples and comparative examples were molded and evaluated in accordance with Tables 1 to 4 in the same manner as in Example 1.

The molding methods shown in Tables 1 to 4 were carried out as follows.
<Molding Condition 1>
The ingredients were mixed by stirring, and then molded into a sheet of a predetermined thickness using a twin roll set at 180°C.
<Molding Condition 2>
The ingredients were mixed in a Henschel mixer, kneaded in a Banbury mixer, and molded into a sheet of a predetermined thickness at a set temperature of 160° C. using a calendar molding machine.

The examples and comparative examples were evaluated using the following methods.

Weather resistance 1 and weather resistance 2 were evaluated by conducting a weather resistance test under the following test conditions, and then visually observing the film surface after a specified time and evaluating ΔYI, which is the change in yellowness index (YI).

<Weather resistance test>
The weather resistance tests in Weather Resistance 1 and Weather Resistance 2 were carried out in the following manner.
Two films of the examples or comparative examples were stacked on the sample plate of the following weather resistance tester, and the periphery was fixed with aluminum tape to conduct the test. The weather resistance tester used was a Daipla Wintes ultra-accelerated weather resistance tester (using a water-cooled metal halide lamp, model: KW-R6TP-A), and accelerated weather resistance tests were conducted for a specified time under the conditions of panel temperature 63°C, humidity in the chamber 50% RH, shower ring interval of 2 hours, shower spray time of 120 seconds, and irradiance of 60 mW/cm^2. After 304 hours of weather resistance 1 and 608 hours of weather resistance 2, the topmost film of the two films stacked on the sample plate was taken out and evaluated.

<Method of measuring yellowness index (YI)>
Yellowness index (YI) was measured using an SM color computer (model number: SM-4-2) manufactured by Suga Test Instruments Co., Ltd. The film of the examples or comparative examples after molding or after a predetermined time of accelerated weather resistance test was placed on the measurement opening of the SM color computer, and the film was covered with a white calibration standard plate (made of ceramic, tristimulus values: X: 77.25, Y: 79.97, Z: 92.71) to measure yellowness index (YI).
<Calculation method of ΔYI>
From the yellowness index (YI) measured by the above method, ΔYI was calculated according to the following formula.
"ΔYI" = "Yellowness (YI) measured after a weather resistance test for a specified period of time" - "Yellowness (YI) measured before a weather resistance test"

<Weather resistance 1>
After carrying out the above weather resistance test for 304 hours, the surface was visually observed and the change in yellowness index (YI), ΔYI, was calculated according to the above method.
[Evaluation Criteria]
. . . ΔYI≦15 or almost no yellowing observed by visual observation, or both.
◯: 15<ΔYI≦30 or partial yellowing was visually observed, or both.
Δ: 30<ΔYI≦60 or yellowing is observed overall by visual inspection, or both.
× . . . 60<ΔYI or significant yellowing was observed by visual observation, or both.

<Weather resistance 2>
After carrying out the above weather resistance test for 608 hours, the surface was visually observed and the change in yellowness (YI) by the above method, ΔYI, was calculated. Note that the notation "-" in Weather Resistance 2 in each table indicates that the yellowing in Weather Resistance 1 was so great that it was determined that evaluation could not be continued for 304 hours or more, and therefore evaluation was not performed for 608 hours.
[Evaluation Criteria]
. . . ΔYI≦15 or almost no yellowing observed by visual observation, or both.
◯: 15<ΔYI≦30 or partial yellowing was visually observed, or both.
Δ: 30<ΔYI≦60 or yellowing is observed overall by visual inspection, or both.
× . . . 60<ΔYI or significant yellowing was observed by visual observation, or both.

<Processability>
Regarding the processability when molding was performed under <Molding Condition 1> or <Molding Condition 2>, roll adhesion and plate-out were evaluated.
[Evaluation Criteria]
◯: No adhesion to rolls or plate-out, excellent processability. Δ: Adhesion to rolls or plate-out occurs, but processability is possible. ×: Significant adhesion to rolls or significant plate-out occurs, and processability is poor.

<Ease of use>
The films of the Examples and Comparative Examples were evaluated for workability after molding.
[Evaluation Criteria]
◯: It can be stretched with almost no wrinkling and can be applied without any problems. △: It wrinkles a little, but it can be stretched without any problems and can be applied. ×: It wrinkles significantly, it is too hard to stretch, or it is too soft and stretches too much to stretch, so it cannot be applied.

<Evaluation method for workability>
The film was evaluated by heating and winding it around a device with a cylindrical metal mandrel fixed horizontally. Specifically, one end of the film of the embodiment or comparative example was fixed with tape to the underside of a metal cylinder (diameter 100 mm). A Leister (hot air welding machine, manufactured by LEISTER Process Technologies (Leister, Switzerland), model number: Leister Triac PID) was set to 110°C on the LCD display of the main unit. The other end of the film that was not fixed was held by hand, and while lightly pulling the film, the hot air of the Leister set at 110°C was applied to the film for 10 seconds to heat it. Immediately after heating for 10 seconds, the Leister was placed to the side and the other end of the film was pulled with one hand, and the film was rubbed with the other hand to fit it along the cylinder, and the state of the film at that time was evaluated according to the above evaluation criteria.

<Plasticizer migration rate>
For the films of the Examples and Comparative Examples, the plasticizer migration rate after molding was measured, and the plasticizer migration rate was calculated and evaluated according to the following calculation method.
[Evaluation Criteria]
◯: Plasticizer migration rate is less than 1%. The migration of plasticizer is small and good.
△: Plasticizer migration rate is 1% or more and less than 3%. There is migration of plasticizer, but it does not cause problems in use.
×: Plasticizer migration rate is 3% or more. Plasticizer migration is high and cannot be used.

<Method for measuring plasticizer migration rate>
The plasticizer migration test was carried out in the following manner.
A film of the embodiment or comparative example having a diameter of 70 mm is prepared, and the weight of the film before the test is measured. The film whose weight was measured is sandwiched between two polypropylene sheets having a diameter of 70 mm and a thickness of 750 μm, and placed on a sample plate of a high-temperature chamber (ESPEC Co., Ltd., small high-temperature chamber, model: ST-120B1), and a weight of 1 kg is applied. The high-temperature chamber is set to 60° C., and after 24 hours, the film is removed from the high-temperature chamber together with the polypropylene sheets and the weight. The removed film is left to stand for 30 minutes while sandwiched between the polypropylene sheets with the weight placed thereon, and the weight of the removed film is measured. The weight is measured in g to the fourth decimal place using an electronic balance.

<Calculation method for plasticizer migration rate>
(Weight of PVC film before test [g] - Mass of PVC film after test [g]) / Weight of PVC film before test [g] x 100% = Plasticizer migration rate [%]
The plasticizer migration rate was rounded off to one decimal place.
<Overall evaluation>
Weather resistance 1, weather resistance 2, initial color tone, processability, workability, and plasticizer migration rate were evaluated comprehensively, with ○ being excellent in weather resistance, initial color tone, processability, workability, and plasticizer migration rate, △ being generally good although there are some poor parts in weather resistance, initial color tone, processability, workability, and plasticizer migration rate, and × being significantly poor in any of weather resistance, initial color tone, processability, workability, and plasticizer migration rate, and being judged as unacceptable. Here, with regard to weather resistance, if weather resistance 1 was rated as ◎ or ○, then even if weather resistance 2 was rated as △ or ×, the weather resistance was rated as acceptable.

Claims (5)

A base film for application to vehicle bodies that contains 100 parts by weight of polyvinyl chloride resin, 20 to 40 parts by weight of polyester plasticizer with a viscosity of 100 mPa·s/25°C to 3500 mPa·s/25°C, 0.1 to 10 parts by weight of ultraviolet absorber, and 0.1 to 10 parts by weight of hindered amine light stabilizer, and does not contain acrylic resin. 2. The substrate film for attachment to a vehicle body according to claim 1, which has a plasticizer migration rate of less than 3% in a plasticizer migration test performed by the following test method.
Test Method
A substrate film for application to a vehicle body having a diameter of 70 mm is prepared, and the weight of the substrate film for application to a vehicle body before the test is measured. The substrate film for application to a vehicle body whose weight has been measured is sandwiched between two polypropylene sheets having a diameter of 70 mm and a thickness of 750 μm, and placed in a high-temperature chamber set at 60° C. for 24 hours, and the weight of the substrate film for application to a vehicle body after cooling is measured.
"Calculation method for plasticizer migration rate"
(Weight of the base film for application to the vehicle body before the test [g] - Mass of the base film for application to the vehicle body after the test [g]) / Weight of the base film for application to the vehicle body before the test [g] x 100% = Plasticizer migration rate [%] The substrate film for application to a vehicle body according to claim 1 or 2, in which the difference in yellowness (ΔYI) between the yellowness before and after 304 hours of accelerated weathering testing using a water-cooled metal halide lamp is less than 30. The substrate film for attachment to a vehicle body according to any one of claims 1 to 3, which is used for a film for attachment to a vehicle body having an adhesive layer. 5. The substrate film for attachment to a vehicle body according to claim 4, which is used as a film for protecting the vehicle body of an automobile.