JP5437189B2 - Cosmetic film - Google Patents

Description

The present invention relates to a cosmetic film.

A decorative film is a kind of decorative material made by printing or laminating a base film, such as a wood board (MDF, particle board, laminated board, etc.), a metal board, an inorganic board (gypsum board, etc.), etc. Used for building materials, furniture, cabinets for household electrical appliances, used as wallpaper for decoration on walls, ceilings, floors, etc. It is a film to be used.

Conventionally, as such a cosmetic film, for example, a cosmetic film in which a base material layer, a printing layer, and a transparent resin layer are laminated in this order has been proposed.
And in such a cosmetic film, the vinyl chloride resin was used for the material of a base material layer and a transparent resin layer (for example, refer patent document 1).
However, since vinyl chloride resin contains chlorine, in recent years, with the background of increasing environmental problems, replacement with a film made of polyolefin resin such as polyethylene resin or polypropylene resin is being advanced.

Therefore, for example, in Patent Document 2, a specific polypropylene resin is used as the material of the transparent resin layer, and paper, polyethylene resin, polypropylene resin, polybutylene, polystyrene, polycarbonate, polyester polyamide, ethylene are used as the material of the base material layer. -The use of synthetic resins such as vinyl acetate copolymer, polyvinyl alcohol and acrylic, foams of these synthetic resins, rubber, non-woven fabric, synthetic paper, metal foil and the like is described.

JP-A-5-309731 JP 2001-270054 A

However, when a polypropylene resin is used for the transparent resin layer and a material other than the polypropylene resin is used for the base material layer, the decorative film is warped or curled, resulting in poor handling and good appearance. There was a problem of getting worse.
And it was thought that the cause of such warpage and curling was that the linear expansion coefficients of the base material layer and the transparent resin layer were different.
In addition, in the market for cosmetic films, apart from actual products, products having the same decorative surface as products and having a smaller size are usually used as product samples. Such a product sample cannot play a role as a product sample if warping or curling occurs. In addition, when a polypropylene resin is used for the base material layer, there are disadvantages as described later in terms of moldability, economy, and surface modification.

In the cosmetic film having the structure disclosed in Patent Document 2, when the same material as the base material layer and the transparent resin layer is used, that is, as the material of both the base material layer and the transparent resin layer, polypropylene resin is used. When used, the above-described problems of warping and curling did not occur, but the following problems were encountered.
Polypropylene resin, for example, has a higher melting point than polyethylene resin, and is difficult to mold and handle, and is expensive compared to polyethylene resin, which is economically disadvantageous. It is difficult to quality and tends to be inferior in adhesion to other resins, and has poor weather resistance compared to polyethylene resin. It was.

Therefore, the present inventors have examined the use of a polyethylene resin having a linear expansion coefficient comparable to that of polypropylene resin and easier to mold than polypropylene resin as the material of the base material layer. However, even though the linear expansion coefficients of the base material layer and the transparent resin layer are approximately the same, the occurrence of warpage and curling could not be suppressed. In addition, when a polyethylene resin is used as the material of the base material layer, there may be a disadvantage that the base material layer is deformed or wrinkled due to the thermal history of the process of manufacturing the cosmetic film. there were.

That is, at present, a cosmetic film in which a transparent resin layer made of a polypropylene resin is laminated on a base material layer has a big problem that it cannot simultaneously solve a plurality of problems as described above.

The inventors of the present invention have made extensive studies and have been able to solve the above-mentioned problems, and have completed a cosmetic film having excellent design properties as well as excellent handleability because no warping or curling occurs.

The cosmetic film of the present invention is a cosmetic film in which at least a base material layer and a transparent resin layer are laminated in this order,
The base material layer is composed of a mixture of a polyethylene resin and a polypropylene resin, and the content of the polyethylene resin is larger than the content of the polypropylene resin.
The transparent resin layer is made of polypropylene resin.

In the cosmetic film of the present invention, the content of the polypropylene resin in the total amount of the polyethylene resin and the polypropylene resin in the mixture of the polyethylene resin and the polypropylene resin is preferably 5 to 30% by weight.
As for the cosmetic film of this invention, it is desirable to provide a printing layer between the said base material layer and the said transparent resin layer.
As for the cosmetic film of this invention, it is desirable for the surface of the said transparent resin layer to be surface-treated.
As for the base material layer which comprises the cosmetic film of this invention, it is desirable for a polyethylene resin to have the sea island structure where a polyethylene resin is the sea and a polypropylene resin is an island.

The cosmetic film of the present invention is configured such that the transparent resin layer is made of polypropylene resin, the base material layer is made of a mixture of polyethylene resin and polypropylene resin, and the polyethylene resin content is larger than the polypropylene resin content. Has been.
The polypropylene resin constituting the transparent resin layer is excellent in transparency and scratch resistance. Therefore, it can be imparted to a cosmetic film having these characteristics. And when the said transparent resin layer is excellent in transparency, the said film for cosmetics will be excellent in the designability.
Furthermore, since the said base material layer consists of the said structure, it can prevent that a curvature and curl generate | occur | produce in a cosmetic film, and can provide the handleability which was excellent in the cosmetic film.

The effect of preventing warping and curling from occurring on the cosmetic film will be described in more detail.
In the first place, in a cosmetic film in which the base material layer is made of a polyethylene resin and the transparent resin layer is made of a polypropylene resin, the reason for warping is presumed as follows.
That is, there is a difference in shrinkage ratio between polyethylene resin and polypropylene resin when cooled after heating (polyethylene resin has a larger shrinkage ratio). And when this polypropylene resin film is laminated | stacked on a polyethylene resin film, it is guessed that this shrinkage | contraction rate difference is a cause of curling in the polyethylene resin side with a large shrinkage rate in the obtained laminated body.

The difference in shrinkage between the polyethylene resin and the polypropylene resin has been clarified by the following examination results by the present inventors.
That is, when the shrinkage rate of polyethylene resin and polypropylene resin was measured by the following method, the results shown in Table 1 were obtained. Here, the shrinkage rate is also measured for a resin film obtained by mixing a polyethylene resin and a polypropylene resin.

Specifically, a measurement sample having a blending ratio shown in Table 1 and having a width of 4 mm, a length of 15 mm, and a thickness of 0.07 mm was prepared, and the sample was heated at a heating rate of 10 ° C./min from 40 ° C. to 130 ° C. The amount of change in length (μm) when the temperature was lowered from 130 ° C. to 40 ° C. at a rate of temperature drop of 10 ° C./min was measured using a thermal stress strain measuring device (manufactured by Seiko Instruments Inc., TMA / SS). 120 CU) and the load was 1 MPa. In the table, when the amount of change and the rate of change are negative values, it indicates that the length has become shorter due to shrinkage.

As shown in Table 1, it is clear that there is a difference in shrinkage ratio between polyethylene resin and polypropylene resin when cooled after heating.
Although the reason why the shrinkage rate of the polyethylene resin is larger than the shrinkage rate of the polypropylene resin is not clear as shown in Table 1, high-density polyethylene has higher crystallinity than the random copolymer polypropylene, and once has a melting point. It is assumed that the resin heated up to near has been recrystallized and thus contracted and shortened before heating.

And in the examination of the shrinkage rate mentioned above, another new knowledge was also acquired.
That is, for the film made of a mixture of polyethylene resin and polypropylene resin, the shrinkage rate was measured by the method described above, and it was clear that the rate of change in shrinkage rate was reduced by blending the polypropylene resin with the polyethylene resin. became. Furthermore, surprisingly, the rate of change in shrinkage does not decrease in an amount-dependent manner depending on the amount of polypropylene resin, but the rate of change in shrinkage is reduced by adding a small amount of polypropylene resin. It became clear that it was much smaller than the film consisting only of the film.
And this is considered to be the reason why the cosmetic film of the present invention exhibits the effects described above. These findings are newly discovered by the inventors of the present application.

Furthermore, in the cosmetic film of the present invention, the base material layer is composed of a mixture of a polyethylene resin and a polypropylene resin, and the content of the polyethylene resin is larger than the content of the polypropylene resin. It will be excellent in performance. The reason for this will be described later.

It is sectional drawing which shows an example of the cosmetic film of this invention typically. It is a graph which shows the tension | pulling characteristic evaluated on 23 degreeC and the conditions of a length direction about the film which consists of a film which consists of a polypropylene resin, a film which consists of a polyethylene resin, and a mixture of a polypropylene resin and a polyethylene resin. It is a graph which shows the tension | pulling characteristic evaluated on 23 degreeC and the conditions of a horizontal direction about the film which consists of a polypropylene resin, the film which consists of a polyethylene resin, and the film which consists of a mixture of a polypropylene resin and a polyethylene resin. It is sectional drawing which shows typically another example of the cosmetic film of this invention. It is sectional drawing which shows typically another example of the cosmetic film of this invention. It is the graph which evaluated the effect of the corona treatment of a polyethylene resin and a polypropylene resin. It is a schematic diagram for demonstrating the measuring method of the curl height of a cosmetic film. It is the image (x5000) which observed the base material layer produced in Example 2 with TEM. It is the image (x100,000) which observed the base material layer produced in Example 2 with TEM. It is the image (x5000) which observed the base material layer produced in Example 3 with TEM. It is the image (x100,000) which observed the base material layer produced in Example 3 with TEM. It is the image (x5000) which observed the base material layer produced in Example 5 with TEM. It is the image (x100,000) which observed the base material layer produced in Example 5 with TEM. It is the image (x5000) which observed the film whose ratio of high density polyethylene / random copolymer polypropylene is 42/58 with TEM. It is the image (x100,000) which observed the film whose ratio of high density polyethylene / random copolymer polypropylene is 42/58 with TEM.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view schematically showing an example of the cosmetic film of the present invention.

A cosmetic film 10 shown in FIG. 1 has a base material layer 11, a printing layer 12, an adhesive layer 13, and a transparent resin layer 14 laminated in this order. The surface 14a of the transparent resin layer 14 is subjected to surface treatment.
Here, the base material layer 11 is a layer made of a mixture of a polyethylene resin and a polypropylene resin and configured so that the content of the polyethylene resin is larger than the content of the polypropylene resin.

A printed layer 12 is formed on the base material layer 11. The design drawn on the printed layer 12 becomes the design of the cosmetic film 10.

An adhesive layer 13 is formed on the printing layer 12. The adhesive layer 13 serves to bond the base material layer 11 and the print layer 12 to the transparent resin layer 14. The adhesive layer 13 is transparent so that the design of the printing layer 12 can be visually recognized.

The transparent resin layer 14 is a layer made of polypropylene resin. The reason for using a polypropylene resin as the material of the transparent resin layer 14 is that the surface of the cosmetic film is hardly scratched and has excellent transparency because it has excellent scratch resistance.

The cosmetic film having such a structure can prevent the cosmetic film from being warped or curled even though the base material layer and the transparent resin layer are made of different materials. Excellent handleability can be imparted to the film.

In addition, both the base material layer and the transparent resin layer are easy to handle and economically advantageous because the molding temperature of the base material layer can be set lower than a cosmetic film made of polypropylene resin. Excellent.

Moreover, when selling a cosmetic film, it can be used as a sample product by cutting the cosmetic film into small pieces. When the product sample is warped or curled, the value of the sample is significantly reduced, but when the small piece of the cosmetic film of the present invention is used as the product sample, the product sample is warped or curled. Therefore, the above inconvenience can be avoided.

Since the base film consists of a mixture of a polyethylene resin and a polypropylene resin, the cosmetic film is extremely excellent in weather resistance as compared with a cosmetic film whose base layer is made of a polypropylene resin. This is because a film made of a mixture of a polyethylene resin and a polypropylene resin is superior in weather resistance compared to a film made of a polypropylene resin, and such knowledge has been found for the first time by the present inventor.

Below, the result of having evaluated the weather resistance about each of the film which consists of a film which consists of a polypropylene resin, a film which consists of a polyethylene resin, and a polypropylene resin and a polyethylene resin is shown.

Here, the evaluation sample was produced by the following method.
That is, in 100 parts by weight of blend resin containing high density polyethylene (HDPE / Prime Polymer, Hi-Zex 3300F) and random copolymer polypropylene (r-PP / Sun Allomer, PS621S) in the ratios shown in Table 2. , 0.1 part by weight of an antioxidant (Ciba Japan, Irganox 1076), 0.1 part by weight of calcium stearate, 0.2 part by weight of an ultraviolet absorber (Ciba Japan, Tinuvin 329), and Add 0.3 parts by weight of a light stabilizer (Ciba Japan Co., Ltd., Cimasorb 119FL), melt and knead it with a Banbury mixer, and then feed and roll to a reverse L-shaped four-calendar with a roll temperature of 170-190 ° C. Thus, a measurement sample having a width of 1000 mm, a length of 300 mm, and a thickness of 0.07 mm was produced.

Table 2 shows the results of evaluating the weather resistance of each sample by a test method based on JIS A 1415 (using sunshine carbon (WS type) as a light source).
In the table, “◯” means that the appearance was not changed, and “x” means that a crack occurred in the film.

As shown in Table 2, it is clear that a film made of polyethylene resin or a film made of a mixture of polypropylene resin and polyethylene resin is superior in weather resistance compared to a film made of polypropylene resin.

In addition, according to the knowledge newly obtained by the present inventors, the weather resistance of a film made of a mixture of a polypropylene resin and a polyethylene resin is increased as the content of the polyethylene resin in the mixture increases. Instead of improving depending on the rate, in the mixture of polypropylene resin and polyethylene resin, the content of the polyethylene resin is set to 80% by weight or more (the content of the polypropylene resin is 20% by weight or less). It became clear that the weather resistance equivalent to the film made of polyethylene resin was obtained.
Therefore, in the cosmetic film of the present invention, the content of the polypropylene resin relative to the total amount of the polyethylene resin and the polypropylene resin in the mixture constituting the base material layer is 20% by weight or less, so that the weather resistance is high. It can be suitably used as a required cosmetic film (for example, a cosmetic film used outdoors).

Moreover, since the said base film consists of a mixture of a polyethylene resin and a polypropylene resin, the said film for cosmetics also has an effect that it is excellent in bending workability.
As will be described later, the cosmetic film of the present invention is used by being bonded to a substrate such as a wood plate or a metal plate. Here, the member (decorative plate) to which the decorative film is attached may be processed in a state in which the decorative film is attached, and one of the specific processing examples is to fold the decorative plate. In addition, there is a bending process in which a V-shaped groove is formed on the substrate side, and then the decorative plate is bent at a predetermined angle.
At this time, in the cosmetic film provided with the base material layer made of polypropylene resin, when the decorative board is folded, the cosmetic film may be broken or whitened. On the other hand, such inconvenience can be avoided in the cosmetic film provided with the base material layer made of a mixture of polyethylene resin and polypropylene resin.
About this reason, it estimates as follows.
As described above, when polypropylene resin is used for the base material layer, inconvenience may occur at the time of bending, but in the case of a cosmetic film having a base material layer made of polyethylene resin, the workability of polyethylene resin is polypropylene resin. The above disadvantages can be avoided due to the superiority of the above.
A film made of a mixture of a polyethylene resin and a polypropylene resin has tensile properties similar to those of a film made of polyethylene resin, so that the disadvantage that occurs when a film made of polypropylene resin is used as well as a film made of polyethylene resin. It can be avoided.

Below, the result of having evaluated the tension | pulling characteristic about each of the film which consists of a film which consists of a polypropylene resin, a film which consists of a polyethylene resin, and a polypropylene resin and a polyethylene resin is shown.

2 and 3 each contained high density polyethylene (HDPE / Prime Polymer, Hi-Zex 3300F) and random copolymerized polypropylene (r-PP / Sun Allomer, PS621S) in the ratios shown in Table 3. To 100 parts by weight of the blend resin, 0.1 parts by weight of an antioxidant (manufactured by Ciba Japan Co., Ltd., Irganox 1076) and 0.1 parts by weight of calcium stearate are added, melted and kneaded with a Banbury mixer, and then rolled. It is the result of having evaluated the tension | pulling characteristic of the film (sample No. 1-7) of thickness 0.07mm produced by supplying to the reverse L type | mold 4 calendar | calender of temperature 170-190 degreeC and rolling.

Here, the tensile properties were evaluated in accordance with JIS K 6732, at a measurement temperature of 23 ° C., a pulling speed of 50 mm / min, and the pulling direction in the vertical direction (FIG. 2) or the horizontal direction (FIG. 3). In addition, the said vertical direction means the extending | stretching direction of a calendar process, and the said horizontal direction means the direction (width direction of a film) perpendicular | vertical to a vertical direction.

From the graphs shown in FIGS. 2 and 3, it is clear that the tensile properties of a film made of a mixture of polypropylene resin and polyethylene resin are different from those made of polypropylene resin and approximate to a film made of polyethylene resin.

Here, first, when comparing the tensile properties of a film made of polypropylene resin and a film made of polyethylene resin, the film made of polyethylene resin stretches while gradually necking uniformly, whereas the polypropylene resin The film made of is considered to be highly rigid and stretched while partially necking (partially broken in a microscopic region) after the yield point. In addition, it is estimated from the curve after the yield point that the film which consists of a polypropylene resin has fractured | ruptured partially.
And this difference in behavior may be due to the difference in molecular structure that polyethylene resin is oriented in a planar structure, whereas polypropylene resin is complicated in three dimensions. Conceivable.
Then, when considering the bending process of the decorative board, the above process is generally considered to be performed in a low extension region up to the yield point, the film made of polypropylene resin, compared to the film made of polyethylene resin, It is considered that the film made of polyethylene resin is superior to the film made of polypropylene resin because it has high rigidity and is easy to break.

As described above, a film made of a mixture of polypropylene resin and polyethylene resin has a tensile property similar to a film made of polyethylene resin, and a base material layer made of a mixture of polypropylene resin and polyethylene resin The provided cosmetic film of the present invention is considered to have better folding processability than a cosmetic film provided with a base material layer made of polypropylene resin.

In addition, since the processing of the decorative board as described above is usually performed at room temperature, in the cosmetic film of the present invention, the polypropylene with respect to the total amount of the polyethylene resin and the polypropylene resin in the mixture constituting the base material layer. Bending workability can be further improved by setting the resin content to 30% by weight or less.
The reason for this is that, as shown in FIGS. 2 and 3, the content of the polypropylene resin is 30 wt% or less (the content of the polyethylene resin is 70 wt% with respect to the total amount of the polyethylene resin and the polypropylene resin in the mixture constituting the base material layer). This is because the tensile properties (yield point stress and elongation) are very close to those of a film made of polyethylene resin.
And the knowledge regarding these bending workability is also newly found by the present inventors.

Furthermore, when the tensile properties of the mixture having a polypropylene resin content of 30% by weight or less with respect to the total amount of the polyethylene resin and the polypropylene resin approximate that of the polyethylene resin, in the film made of such a mixture, the polyethylene resin becomes a polypropylene resin. It has the same advantages as the advantages that it has, that is, excellent processability and moldability (for example, moldability by calendering), and various processing is performed under the same conditions as a film made of polyethylene resin. It is thought that you can.

The transparent resin layer is formed using a polypropylene resin as described above. It does not specifically limit as said polypropylene resin, For example, homopolymerization polypropylene resin (h-PP), random copolymerization polypropylene resin (r-PP), block copolymerization polypropylene resin (b-PP), metallocene polypropylene resin etc. are mentioned. It is done.
These may be used alone or in combination of two or more.
Among these, a random copolymer polypropylene resin is desirable. The reason is that the random copolymer polypropylene resin is less likely to be whitened at the time of bending as compared with the homopolymer polypropylene resin and the block copolymer polypropylene resin.

In addition to the polypropylene resin, an additive may be blended in the transparent resin layer as long as the transparency is not impaired.
Examples of the additive include a lubricant, a heat stabilizer, an antioxidant, an ultraviolet absorber, a light stabilizer, a pigment, a modifier, a flame retardant, an antistatic agent, a reinforcing agent, a filler, and an antifungal agent. Can be mentioned.

Examples of the surface treatment applied to the surface 14a of the transparent resin layer 14 include a coating treatment for the purpose of improving the scratch resistance and stain resistance of the transparent resin layer. The coating treatment can be carried out in combination with ultraviolet treatment or electron beam treatment in addition to applying a paint having the above functions. What is necessary is just to give the said surface treatment as needed.

The base material layer is formed using a mixture of a polyethylene resin and a polypropylene resin as described above.
As said polypropylene resin, the thing similar to the polypropylene resin used for the said transparent resin layer is mentioned.

Examples of the polyethylene resin include high density polyethylene (HDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), and very low density polyethylene (VLDPE).
These may be used alone or in combination of two or more.
Among these, high density polyethylene (HDPE) and linear low density polyethylene (LLDPE) are desirable, and high density polyethylene (HDPE) is particularly desirable.
This is because high-density polyethylene is particularly excellent in weather resistance and tensile strength.
Further, among the above-mentioned polyethylene resins, high-density polyethylene is particularly suitable for molding into a film by calendering because it is excellent in heat resistance and processability during processing, and when using high-density polyethylene, Even if it is a long scroll, there is no slack and poor appearance due to whitening is less likely to occur during bending.
In addition to the polyethylene resin and the polypropylene resin, an additive may be added to the base material layer. Examples of the additive include the same additives as those that can be added to the transparent resin layer.

In the base material layer, the content of the polyethylene resin is larger than the content of the polypropylene resin. If there are more polypropylene resins, there is a problem that depends on the properties of the polypropylene resin (high melting point and difficult to mold, difficult to handle, and expensive compared to polyethylene resin, which is economically disadvantageous, This is because surface modification is difficult compared to polyethylene resin, and the weather resistance is inferior to polyethylene resin, and the adhesion to other resins tends to be inferior).

In addition, the content of the polypropylene resin relative to the total amount of the polyethylene resin and the polypropylene resin reduces the shrinkage amount of the base material layer while suppressing the occurrence of defects depending on the polypropylene resin, and warps the decorative film. And 5% by weight or more are desirable in that generation of curls and curls can be suppressed.
And in order to prevent generation | occurrence | production of curvature and a curl more reliably, it is more desirable that it is 10 weight% or more, and it is still more desirable that it is 20 weight% or more.

Furthermore, the ratio of the thickness of the base material layer to the transparent resin layer (the thickness of the transparent resin layer / the thickness of the base material layer) is 2, 3 to 6.0, or 0.03 When it is ˜0.11, the content of the polypropylene resin with respect to the total amount of the polyethylene resin and the polypropylene resin is preferably 10 to 30% by weight.

On the other hand, as already described, in terms of improving the weather resistance and folding processability of the cosmetic film, the content of the polypropylene resin relative to the total amount of the polyethylene resin and the polypropylene resin is 30% by weight or less (above The content of the polyethylene resin is desirably 70% by weight or more. In particular, in terms of improving weather resistance, the content of the polypropylene resin is more preferably 20% by weight or less (the content of the polyethylene resin is 80% by weight or more).

Therefore, the content of the polypropylene resin relative to the total amount of the polyethylene resin and the polypropylene resin is particularly preferably 5 to 30% by weight (the content of the polyethylene resin is 70 to 95% by weight). Most preferably, it is 20% by weight (polyethylene resin content is 80 to 95% by weight).
This is because, within this range, it is possible to suppress warping and curling of the cosmetic film, and at the same time, to obtain excellent weather resistance and bending workability.

The base material layer preferably has a sea-island structure in which polyethylene resin is the sea and polypropylene resin is the island. In this case, there is an effect that it is excellent in cutting processability after the cosmetic film is attached to a plywood or the like.
Although this reason is not certain, it is considered that it is easily cut through the interface between the sea and the island (the interface between the polyethylene resin and the polypropylene resin).

Moreover, when the said base material layer has the said sea-island structure, it is advantageous also at the point that it is easy to suppress generation | occurrence | production of the curvature and curl of the said cosmetic film.
When the base material layer has a sea-island structure in which polyethylene resin is the sea and polypropylene resin is the island, the reason why the occurrence of the warp and curl is easily suppressed is as described above. Since the shrinkage rate is smaller than the shrinkage rate of polyethylene resin, the island part made of polypropylene resin works to prevent the sea part made of polyethylene resin from shrinking, and as a result, the base material layer as a whole It is thought that the contraction of the skin is suppressed.

Moreover, when the said base material layer has the said sea island structure, the bending workability of the decorative board which stuck the said cosmetic film can be improved. The reason for this is thought to be that the tensile properties approximate that of a film made of polyethylene resin.

Further, a primer may be formed on the surface of the base material layer, particularly on the surface on the side where the printing layer is formed.
Examples of the primer include polyurethane resins and urethane-acrylic copolymer resins obtained by crosslinking with isocyanate.

The adhesive layer is not particularly limited as long as it can adhere the substrate layer having the printed layer formed on the upper surface thereof and the transparent resin layer, and does not impair the visibility of the printed layer.
Examples of the adhesive layer include acrylic adhesives and urethane adhesives.

The acrylic adhesive is made of an acrylic polymer, and examples of the acrylic polymer include a homopolymer of (meth) acrylic acid alkyl ester or a copolymer thereof. it can. As alkyl in the said (meth) acrylic-acid alkylester, C4-C12 linear or branched alkyl is preferable.

As the urethane-based adhesive, a one-component curing type or a two-component curing type polyurethane-based adhesive can be used, and among these, a two-component curing type urethane-based adhesive using a reaction between an isocyanate and a polyol. Is desirable.
In addition, as will be described later, the cosmetic film of the present invention may not include an adhesive layer.

In the cosmetic film 10, for example, the surface of the base material layer 11 on the transparent resin layer 14 side may be embossed, and the surface of the transparent resin layer 14 is embossed. Also good.
Thereby, the appearance of a design can be improved and the variation of a design can be increased.

The cosmetic film of the present invention is not limited to the structure as shown in FIG. 1, and may have a structure as shown in FIGS.
4 and 5 are cross-sectional views schematically showing another example of the cosmetic film of the present invention.

In the decorative film 20 shown in FIG. 4, a transparent resin layer 24 is directly formed on the printing layer 22 on the base material layer 21 on which the printing layer 22 is laminated without using an adhesive layer.
Thus, in the cosmetic film of this invention, the adhesive bond layer does not need to be formed. By omitting the adhesive layer in this manner, the printed layer is visually recognized without going through the adhesive layer, so that the design can be made clearer.

In the cosmetic film of the present invention, when the adhesive layer is omitted, the following method can be employed in order to ensure adhesion between the transparent resin layer and the printed layer (or base material layer).
For example, (1) a method of blending a resin having an adhesive function as a printing ink for forming a printing layer, (2) surface treatment such as corona treatment on the surface of the transparent resin layer facing the base material layer. It is possible to adopt a method of placing the image.

The cosmetic film 30 shown in FIG. 5 has the same configuration as the cosmetic film 10 shown in FIG. 1 except that it does not have a printing layer. In FIG. 5, 31 is a base material layer, 33 is an adhesive layer, and 34 is a transparent resin layer.
In such a cosmetic film 30, the surface of the base material layer itself becomes the design of the cosmetic film 30.
Further, the cosmetic film of the present invention may be one in which the adhesive layer 33 is not formed in the cosmetic film 30 shown in FIG.

The thickness of the cosmetic film of the present invention is not particularly limited, and may be appropriately selected according to the purpose of use, but is usually 45 μm to 1 mm.
More specifically, for example, if it is a cosmetic film used for a portion that occupies a relatively large area in a wall paper, a ceiling, a floor, etc., or a cabinet of building materials, furniture, and household electrical appliances, 70 If it is a cosmetic film used in a part that requires more excellent impact resistance or pressure dent resistance, such as an edge part of the cabinets, it is preferably 0.5 to 1 mm. It is desirable that

Moreover, about the thickness of each layer which comprises the cosmetic film of this invention, a base material layer is 40-950 micrometers normally, an adhesive bond layer is 1-50 micrometers, and a transparent resin layer is 1-500 micrometers.

The cosmetic film of the present invention having such a configuration can be produced, for example, by the following production method.
Next, the method for producing the cosmetic film of the present invention will be described in the order of steps.

(1) First, a base material layer is prepared.
The base material layer can be produced by, for example, an existing method such as calendering or extrusion, and is preferably produced by calendering.
The reason why calendering is desirable is that, due to the structure of the molding machine, it is easy to deal with many colors, sizes and types of resins, and it is easy to deal with small lots. In addition, calendering is suitable for producing a thin layer with high thickness accuracy compared to extrusion.
Furthermore, calendering is suitable for producing a film that is thin and excellent in concealment as compared with extrusion. This is because in extrusion processing, when supplying raw materials, the pigment and the resin material are put into the supply machine, both are stirred in the supply machine, and then supplied to the extrusion machine, but conveyed from the supply machine to the extrusion machine. In the process, the resin material and the pigment are separated (both are in a non-uniformly dispersed state (especially when the pigment is an inorganic pigment, it tends to be non-uniform)). As a result, in a film formed by extrusion molding In some cases, the blending ratio of the resin component and the pigment varies with time. And, since the film with such variation may have a variation in its concealment property, which may lead to a decrease in value as a product (film), such a problem does not occur in calendering. is there.

When the base material layer is produced by calendering, for example, it can be produced as follows. First, a polyethylene resin and a polypropylene resin are mixed in a predetermined blending amount, and additives and the like are added to the mixture as necessary.
This is melted by heating and kneading at 150 to 200 ° C. with a continuous kneader, Banbury mixer, kneader, extruder or the like. The base material layer can be produced by supplying the molten resin to a calender roll having a roll temperature of 150 to 200 ° C. and rolling it.
Here, as the calendar, those usually used such as a three-type, four-L type, four-inverted L-type, four-Z type, and six-type can be used.
In this step, it is important to sufficiently knead the polyethylene resin and the polypropylene resin in order to make the base material layer have a sea-island structure.

Moreover, after producing the said base material layer, you may surface-treat to the surface (especially surface on the side facing a transparent resin layer) of a base material layer as needed.
Examples of the surface treatment include corona treatment, plasma treatment, ultraviolet treatment, and electron beam treatment. By performing these treatments, the adhesiveness between the base material layer and the printed layer, the adhesive layer or the transparent resin layer can be improved. Moreover, the storage stability of the base material layer subjected to the surface treatment is also improved.
As the surface treatment, corona treatment is desirable. The reason is that it is easy to improve adhesiveness. Corona treatment also has the advantage that it is easy to construct a processing environment (processing device).

In addition, the compatibility with the corona treatment is one of the reasons why the base material layer having the above-described configuration is used as the base material layer in the present invention.
That is, when comparing the Nule index attenuation, which is one of the surface modification performances of the polyethylene resin and the polypropylene resin by corona treatment, the polyethylene resin is more excellent in Nure index attenuation. Therefore, it consists of a mixture of polyethylene resin and polypropylene resin, and the base material layer in which the content of polyethylene resin is larger than the content of polypropylene resin is more stable in the long term than the base material layer made of polypropylene resin alone. Because it is excellent.
In addition, the above-described excellent Nure index attenuation means that the Nure index is not easily attenuated over a long period of time and is excellent in long-term stability.

Thus, it is clear from the following examination results that the polyethylene resin is more excellent in Nuree index attenuation.
FIG. 6 is a graph evaluating the effect of corona treatment of polyethylene resin and polypropylene resin.
FIG. 6 plots the time-dependent change of the Nuree index when polyethylene resin is corona treated under the condition of 3.0 KW and when polypropylene resin is corona treated under the conditions of 3.0 KW and 5.0 KW. Yes.
In the figure, the broken line is drawn at a wet index of 40 mN / m, which is a measure of the wet index required when a printed layer is formed on the base material layer.
And as shown in FIG. 6, in polyethylene resin, the Nure index of 40 mN / m or more is maintained over a long period (at least 200 days), whereas in polypropylene resin treated under the same conditions, immediately after treatment. Therefore, it is clear that even if the corona treatment is performed at a higher voltage, the Nure index is lower than that of the polyethylene resin immediately after the treatment, and the long-term stability is inferior.

The surface of the base material layer may be subjected to a primer treatment.
The primer treatment may be used in combination with the surface treatment or may be performed alone.
The primer treatment can be performed, for example, by applying a polyurethane resin or a urethane-acrylic copolymer resin obtained by cross-linking with an isocyanate, and then drying as necessary.

(2) Next, a printing layer is formed on the base material layer.
The method for forming the printing layer is not particularly limited, and a conventionally known printing method such as direct gravure printing, offset printing, screen printing, flexographic printing, electrostatic printing, and inkjet printing can be used. In addition, what is necessary is just to form a printing layer as needed.
Further, in the case of forming a printing layer by gravure printing, for example, in the case of a process capable of multicolor printing, an adhesive layer (or primer layer) may be provided on the last gravure roll in a process continuous with pattern printing. . In this case, the printing layer and the adhesive layer can be formed simultaneously.
Moreover, when forming a printing layer, after once forming a solid coating layer on a base material layer, you may draw a pattern on the solid coating layer.

(3) Next, a transparent resin layer is formed separately.
The said transparent resin layer can be produced by the existing methods, such as a calendar process and an extrusion process, similarly to preparation of the said base material layer.
When the transparent resin layer is produced by calendering, for example, it can be produced as follows.
That is, after adding an additive etc. to a polypropylene resin as needed, this is heat-kneaded at 150-200 degreeC with a continuous kneader, a Banbury mixer, a kneader, an extruder, etc., and is melted. The transparent resin layer can be produced by supplying the molten resin to a calender roll having a roll temperature of 150 to 200 ° C. and rolling it.
Here, as the calendar, the same type as that used in the production of the base material layer can be used.
In addition, when the transparent resin layer is produced by extrusion, as in the case of calendering, after adding additives and the like to the polypropylene resin as necessary, it can be formed into a film with an extruder. Good. Further, a continuous kneader, a Banbury mixer, a kneader, an extruder, and the like may be provided before the extrusion molding machine, and what is heated and melted may be supplied to the extrusion molding machine.

Moreover, after forming the said transparent resin layer, you may surface-treat on the surface at the side facing the base material layer of the said transparent resin layer.
Examples of the surface treatment include corona treatment, plasma treatment, ultraviolet treatment, and electron beam treatment. This is because, by performing these treatments, the adhesion with the base material layer, the printing layer, or the adhesive layer can be improved, although not as much as when the corona treatment is applied to the polyethylene resin.

(4) Next, a laminate of the base material layer and the printed layer produced in the steps (1) and (2) (or a simple substance of the base material layer) and a transparent resin produced in the step (3) The layers are bonded together via an adhesive layer.
Here, an acrylic adhesive, a one-component curable type or a two-component curable polyurethane adhesive, a laminate of the base material layer and the printing layer (or base material layer), and / or the surface of the transparent resin layer The two are bonded to each other by being applied to and cured by heating.
In addition, after the laminate and the transparent resin layer are bonded together, the surface of the transparent resin layer (the surface opposite to the side bonded to the laminate) is subjected to a surface treatment such as an ultraviolet treatment or an electron beam treatment. Also good. Moreover, you may perform these surface treatments before bonding.
In addition, what is necessary is just to form the said adhesive bond layer as needed, and may bond together both by the method mentioned above, without forming an adhesive bond layer.
The cosmetic film of the present invention can be produced through such steps (1) to (4).

In such a method for producing a cosmetic film, the base material layer may receive a heat history in the primer treatment or the step (4).
And since the said base material layer contains a polypropylene resin in addition to a polyethylene resin as already demonstrated, the degree of shrinkage | contraction at the time of receiving a heat history compared with the film which consists of polyethylene resins becomes remarkably small. ing.
Therefore, in this respect, the cosmetic film of the present invention is superior to a cosmetic film using a film made of polyethylene resin as the base material layer.

Such a cosmetic film of the present invention is bonded to a substrate such as a wooden board (MDF, particle board, laminated board, etc.), a metal board, an inorganic board (gypsum board, etc.), and is used for building materials, furniture, and household electrical appliances. It is suitable for use as cabinets, as wallpaper used on walls, ceilings, floors, etc. for decoration purposes, and as a cosmetic film used on signs and outer walls outdoors.

EXAMPLES Hereinafter, although an Example is hung up and demonstrated in more detail about this invention, this invention is not limited only to these Examples.

(Examples 1-6, Comparative Example 1)
(1) Production of base material layer High density polyethylene (HDPE / Prime Polymer, Hi-Zex 3300F) and random copolymerized polypropylene (r-PP / Sun Allomer, PS621S) were contained in the ratios shown in Table 4. 0.1 parts by weight of antioxidant (manufactured by Ciba Japan, Irganox 1076), 0.1 part by weight of calcium stearate, UV absorber (manufactured by Ciba Japan, Tinuvin 329) After adding 2 parts by weight and 0.3 parts by weight of a light stabilizer (manufactured by Ciba Japan Co., Ltd., Chimassorb 119FL) and melt-kneading with a Banbury mixer, a reverse L-shaped four-calendar with a roll temperature of 170 to 190 ° C The base material layer having a thickness of 0.07 mm was produced by supplying to the substrate and rolling.
In addition, the thickness of the base material layer was measured according to JIS K 7130. The measurement surface was 10 mmφ.

(2) Production of cosmetic film As a transparent resin layer, an unstretched polypropylene film (manufactured by Tosero Co., Ltd.) having a thickness of 0.07 mm was prepared, and the unstretched polypropylene film and the substrate produced in the step (1) above. The layer (film consisting of HDPE and r-PP) was hot-pressed at 165 ° C. for 1 minute under a pressure of 3 Mpa, and then allowed to cool to room temperature to produce a cosmetic film.
Therefore, here, the produced cosmetic film has a ratio of the thickness of the transparent resin layer and the base material layer (the thickness of the transparent resin layer / the thickness of the base material layer) of 1.0.

Next, the curl height of each manufactured cosmetic film was measured to evaluate the presence or absence of curling.
FIG. 7 is a schematic diagram for explaining a method for measuring the curl height of a cosmetic film.
As shown in FIG. 7, the decorative film 50 is placed on the flat surface 59 so that the base layer 51 is on the upper side and the transparent resin layer 54 is on the lower side. (H in FIG. 7) was measured. In addition, the size of the test piece was 100 mm wide × 100 mm long.
Based on the height, the presence or absence of curling was evaluated according to the following criteria.
○: The height is less than 5 mm.
Δ: The height is 5 mm or more and less than 10 mm.
X: The height is 10 mm or more.

(Examples 7 to 12, Comparative Example 2)
A cosmetic film was produced in the same manner as in Example 1 except that the thickness of the base material layer was 0.05 mm, and the presence or absence of curling of each cosmetic film was evaluated in the same manner as in Example 1. did. The results are shown in Table 5.
Here, the manufactured cosmetic film has a thickness ratio of the transparent resin layer and the base material layer (the thickness of the transparent resin layer / the thickness of the base material layer) of 1.4.

(Examples 13 to 18, Comparative Example 3)
A cosmetic film was produced in the same manner as in Example 1 except that the thickness of the base material layer was 0.04 mm, and the presence or absence of curling of each cosmetic film was evaluated in the same manner as in Example 1. did. The results are shown in Table 6.
Here, the manufactured cosmetic film has a thickness ratio of the transparent resin layer and the base material layer (the thickness of the transparent resin layer / the thickness of the base material layer) of 1.75.

(Examples 19 to 25, Comparative Example 4)
A cosmetic film was produced by the same method as in Example 1 except that the thickness of the base material layer was 0.03 mm, and the presence or absence of curling of each cosmetic film was evaluated by the same method as in Example 1. did. The results are shown in Table 7.
Here, the manufactured cosmetic film has a thickness ratio of the transparent resin layer to the base material layer (the thickness of the transparent resin layer / the thickness of the base material layer) of 2.3.

(Examples 26 to 31, Comparative Example 5)
A cosmetic film was produced in the same manner as in Example 1 except that the thickness of the base material layer was 1.0 mm, and the presence or absence of curling of each cosmetic film was evaluated in the same manner as in Example 1. did. The results are shown in Table 8.
Here, the manufactured cosmetic film has a ratio of the thickness of the transparent resin layer and the base material layer (the thickness of the transparent resin layer / the thickness of the base material layer) of 0.7.

(Examples 32-38, Comparative Example 6)
The thickness of the base material layer is 0.05 mm, and the transparent resin layer is a transparent resin layer having a thickness of 0.2 mm obtained by laminating (hot pressing) two non-stretched polypropylene films (manufactured by Tosero Co., Ltd.) having a thickness of 0.1 mm. A cosmetic film was produced in the same manner as in Example 1 except that was used, and the presence or absence of curling of each cosmetic film was evaluated in the same manner as in Example 1. The results are shown in Table 9.
Here, the manufactured cosmetic film has a thickness ratio of the transparent resin layer and the base material layer (the thickness of the transparent resin layer / the thickness of the base material layer) of 4.0.

(Examples 39 to 45, Comparative Example 7)
The thickness of the base material layer is 0.05 mm, and a transparent resin layer having a thickness of 0.3 mm obtained by laminating (hot pressing) three 0.1 mm thick non-stretched polypropylene films (manufactured by Tosero) A cosmetic film was produced in the same manner as in Example 1 except that was used, and the presence or absence of curling of each cosmetic film was evaluated in the same manner as in Example 1. The results are shown in Table 10.
Here, the manufactured cosmetic film has a thickness ratio between the transparent resin layer and the base material layer (the thickness of the transparent resin layer / the thickness of the base material layer) of 6.0.

(Examples 46 to 52, Comparative Example 8)
A cosmetic film in the same manner as in Example 1 except that the thickness of the base material layer was 0.9 mm, the transparent resin layer was used, and an unstretched polypropylene film (manufactured by Tosero Co., Ltd.) having a thickness of 0.03 mm was used. And the presence or absence of curling of each cosmetic film was evaluated in the same manner as in Example 1. The results are shown in Table 11.
Here, the manufactured cosmetic film has a thickness ratio of the transparent resin layer and the base material layer (the thickness of the transparent resin layer / the thickness of the base material layer) of 0.03.

(Examples 53 to 59, Comparative Example 9)
A cosmetic film was prepared in the same manner as in Example 1 except that the thickness of the base material layer was 0.9 mm and an unstretched polypropylene film (manufactured by Tosero) having a thickness of 0.1 mm was used as the transparent resin layer. Each of the cosmetic films was evaluated for the presence or absence of curling by the same method as in Example 1. The results are shown in Table 12.
Here, the manufactured cosmetic film has a thickness ratio of the transparent resin layer and the base material layer (the thickness of the transparent resin layer / the thickness of the base material layer) of 0.11.

(Examples 60 to 65, Comparative Example 10)
A cosmetic film was prepared in the same manner as in Example 1 except that the thickness of the base material layer was 0.1 mm and an unstretched polypropylene film (manufactured by Tosero) having a thickness of 0.02 mm was used as the transparent resin layer. Each of the cosmetic films was evaluated for the presence or absence of curling by the same method as in Example 1. The results are shown in Table 13.
Here, the manufactured cosmetic film has a thickness ratio of the transparent resin layer and the base material layer (the thickness of the transparent resin layer / the thickness of the base material layer) of 0.2.

Thus, as a base material layer, it consists of a mixture of a polyethylene resin and a polypropylene resin, and when the content of the polyethylene resin is larger than the content of the polypropylene resin, warping and curling occur in the cosmetic film. It became clear that this could be prevented.

Furthermore, the base material layers produced in Examples 2, 3, and 5 were observed with a TEM (transmission electron microscope), and the results are shown in FIGS.
FIGS. 8-1 and 2 are images obtained by observing the base material layer prepared in Example 2 with a TEM at a magnification of 5000 times and 100000 times, respectively. FIGS. FIGS. 10-1 and 2 are images obtained by observing the base material layer produced in Example 5 with TEM at a magnification of 5000 times and 100000 times, respectively. is there.
In addition, a film (reference example) produced in the same manner as in Example 1 except that the ratio (weight%) of high-density polyethylene / random copolymerized polypropylene was 42/58 as a blend resin. And observed by TEM and shown in FIGS.

The observation conditions by TEM are as follows.
Apparatus: Transmission electron microscope (JEOL JEM-1200EX)
Observation conditions: acceleration voltage 80KV
Sample preparation: RuO ₄ staining-ultra thin section method Photo magnification: × 5000, × 100,000
Sword mirror part: middle part of film cross section observed along the flow direction

As a result, each of the base material layers (films) produced in Examples 2 and 3 formed a phase separation structure in which the polyethylene resin was a continuous phase (sea) and the polypropylene resin was a dispersed phase (island). The film was extremely stretched in the flow direction. In addition, although there was no significant difference in the dispersion state between the two, in the base material layer of Example 2, many lamella crystals of polyethylene resin were grown in the direction perpendicular to the flow direction.

The base material layers (films) prepared in Example 5 and Reference Example all form a phase separation structure in which a polypropylene resin is a continuous phase (sea) and a polyethylene resin is a dispersed phase (island), and the flow of the base material layer Stretched significantly in the direction. In addition, there was no significant difference in the dispersion state between the two. Furthermore, lamellar crystals were observed in both the polypropylene resin phase and the polyethylene resin phase, and the polyethylene resin phase was thicker and more prominently observed.

And in the cosmetic film of this invention, it was thought that one of the reasons which has the outstanding effect as mentioned above is that a base material layer has polyethylene resin in the sea, and a polypropylene resin has an island-island structure. .

10, 20, 30 Cosmetic film 11, 21, 31 Base layer 12, 22 Print layer 13, 33 Adhesive layer 14, 24, 34 Transparent resin layer

Claims (5)

A cosmetic film in which at least a base material layer and a transparent resin layer are laminated in this order,
The base material layer is composed of a mixture of a polyethylene resin and a polypropylene resin, and the content of the polyethylene resin is larger than the content of the polypropylene resin.
The said transparent resin layer consists of polypropylene resin, The film for cosmetics characterized by the above-mentioned. The cosmetic film according to claim 1, wherein in the mixture of the polyethylene resin and the polypropylene resin, a content of the polypropylene resin is 5 to 30% by weight with respect to a total amount of the polyethylene resin and the polypropylene resin. The cosmetic film according to claim 1, further comprising a printing layer between the base material layer and the transparent resin layer. The cosmetic film according to any one of claims 1 to 3, wherein a surface treatment is applied to the surface of the transparent resin layer. The cosmetic film according to any one of claims 1 to 4, wherein the base material layer has a sea-island structure in which polyethylene resin is sea and polypropylene resin is island.