JP3016739B2 - Adhesive film for thermal transfer printing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-sensitive adhesive film for thermal transfer printing, and more particularly to a measure for improving printability, weather resistance, and suitability for pasting on a curved surface.

[0002]

2. Description of the Related Art A pressure-sensitive adhesive film for thermal transfer printing has a three-layer structure of an image receiving film, a pressure-sensitive adhesive layer and a support. Printing is performed on the image receiving film by a thermal transfer method. It is used as an outdoor or indoor signboard, a display for advertising, a sticker, a marking material, and the like by being pressure-sensitively bonded so as not to be detached from the adherend.

As the above-mentioned image receiving film, paper and synthetic paper are widely and generally used from ancient times to the present because of their low cost and good usability. In addition, an image receiving film made of a polyester film has been developed.

[0004]

However, an image receiving film made of paper or synthetic paper is poor in strength and flexibility and is suitable for outdoor use and bonding to an adherend having a secondary or tertiary curved surface. Not. On the other hand, an image receiving film made of a polyester film is different in strength from paper and is strong in strength and can withstand outdoor use sufficiently. However, since it is poor in flexibility, it is applied to an adherend having a secondary and tertiary curved surface. What is not suitable for matching is the same as that made of paper.

[0005] Incidentally, there is a polyvinyl chloride film as a general-purpose resin film. This polyvinyl chloride film has excellent weather resistance and flexibility, and can be used not only outdoors but also can be adhered to an adherend having a secondary or tertiary curved surface, so that thermal transfer printing can be performed. It is suitable as an image receiving film for an adhesive film for use.

However, the surface of the polyvinyl chloride film in the adhesive film generally has a thickness of several tens of μm.
Since only a polyvinyl chloride film is used as the image receiving film, the ink is transferred to the convex portions during the thermal transfer printing, but the ink is not transferred to the concave portions. The surface has a spot-like state where the ink has come off, and the printed matter becomes very unsightly. This occurs more remarkably as the number of irregularities increases and the area of the concaves increases.Therefore, it is necessary to take some measures to adopt a polyvinyl chloride film as an image-receiving film of an adhesive film for thermal transfer printing. is there.

The present invention has been made in view of the above circumstances, and an object of the present invention is to obtain a pressure-sensitive adhesive film for thermal transfer printing which is excellent in printability, weather resistance, and curved surface stickability.

[0008]

In order to achieve the above object, the present invention is characterized in that the material, hardness and thickness of the image receiving film and the type of the support are devised.

Specifically, according to the present invention, an adhesive layer is provided on the back surface of an image receiving film to be printed by a thermal transfer method,
On the premise of a pressure-sensitive adhesive film for thermal transfer printing in which a support is provided on the pressure-sensitive adhesive layer in a releasable manner, the following solution was taken.

That is, a first solution of the present invention is that the image receiving film is made of a polyvinyl chloride film.
Further, the hardness of the image receiving film is set to a hardness corresponding to 1.4 to 4 kg / mm ² with a 100% modulus, and the thickness is set to 7%.
Set to 0 to 150 μm. In addition, the support has a basis weight of 5
It is characterized by comprising release paper of 0 g / m ² or less.

According to a second solution of the present invention, based on the above premise, the image receiving film is formed of a polyvinyl chloride film. Further, the hardness of the image receiving film is set to a hardness corresponding to 1.4 to 4 kg / mm ² with a 100% modulus, and the thickness is set to 70 to 150 μm. In addition, the surface roughness of a surface of the support that contacts at least the pressure-sensitive adhesive layer is 20 μm.
It is characterized by comprising a resin film set as follows.

The third solution of the present invention is the first or second solution.
In the above solution, the hardness of the image receiving film is set to 15 to 35 phr in terms of di-2-ethylhexyl phthalate with respect to 100 phr of polyvinyl chloride in terms of the composition of the image receiving film. Characterized in that:

With the above arrangement, in the first to third solutions of the present invention, the flexibility of the image receiving film is appropriately secured so as to reliably follow the curved surface of the adherend and the influence of the surface roughness of the support. Does not adversely affect the surface of the image receiving film and does not cause ink loss. Further, due to the property of polyvinyl chloride having excellent weather resistance, it can sufficiently withstand outdoor use.

Further, the pressure of the print head during thermal transfer printing is evenly transmitted to the image receiving film, and the print head sufficiently presses the convex portion of the image receiving film surface so that the ink is surely transferred to the concave portion, and there is no ink leakage. When the surface of the support that does not contact the pressure-sensitive adhesive layer has a surface roughness of 20 μm or less, if the surface of the support is not in contact with the pressure-sensitive adhesive layer, the surface of the support that does not contact the pressure-sensitive adhesive layer is an image receiving film. The surface of the image receiving film has very little influence on the surface of the image receiving film even if it is stored in a roll form for a long period of time because of the small surface irregularities.

[0015] The fourth solution of the present invention is the first or second solution.
The present invention is characterized in that at least a surface of the support which comes into contact with the pressure-sensitive adhesive layer is subjected to a release treatment.

With the above arrangement, in the fourth solution of the present invention, the image receiving film is easily peeled off from the support when the image receiving film is bonded to the adherend. In addition, when the surface of the support that does not contact the pressure-sensitive adhesive layer is also subjected to a release treatment, the support is in close contact with the image receiving film and is not easily peeled off even if it is wound up in a roll shape and stored for a long time. There is no delamination between the image receiving film and the support during rewinding.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an adhesive film for thermal transfer printing according to an embodiment of the present invention. Reference numeral 1 denotes an image receiving film on which printing is performed by a thermal transfer method, and the back surface of the image receiving film 1 (the side opposite to the image receiving surface). Surface) is provided with a pressure-sensitive adhesive layer 2, and a support 3 is provided on the pressure-sensitive adhesive layer 2 in a releasable manner.

The image receiving film 1 is made of a polyvinyl chloride film. The hardness of the film is determined by adding a plasticizer in the composition to 100 phr of polyvinyl chloride and di-2-phthalate, a phthalate ester plasticizer. Ethylhexyl (DO
By converting to P) and setting it to 15 to 35 phr,
It is determined to be 1.4 to 4 kg / mm ² at 100% modulus. The plasticizer is not limited to a phthalate plasticizer, and may be a polyester plasticizer, a phosphate plasticizer, an epoxy plasticizer, or other various plasticizers. Modulus 1.4 ~
What is necessary is just to add a plasticizer so that it may become 4 kg / mm < ² >. In particular, if a polyester plasticizer is used, the ink on the image receiving surface hardly comes off even when peeled off with a cellophane tape or when scratched with a nail, there is almost no bleeding, the printability is good, the storage stability with time is excellent, and the fogging property is good. It is preferable because the hardness is stable. Examples of the polyester plasticizer include W-305 manufactured by Dainippon Ink and Chemicals, Inc.
Etc. Here, the 100% modulus refers to the modulus when the test piece (image receiving film 1) is stretched by 100%.

Thus, the hardness of the image receiving film 1 is set to 10
Was set to be 1.4~4kg / mm ² at 0% modulus is less than 1.4 kg / mm ^2, influence of the surface roughness of the support 3 and the image-receiving film 1 is too soft and the image receiving film It adversely affects the surface of No. 1 and causes ink loss. On the other hand, if it exceeds 4 kg / mm ² , the image receiving film 1 will be adversely affected.
Becomes too hard and lacks flexibility.
This is because it is difficult to ensure that the object conforms to the curved surface of the adherend.

The image receiving film 1 has a thickness of 70 to 70.
It is set to 150 μm. The reason for this is that if it is less than 70 μm, the surface roughness of the support 3, that is, unevenness, is too thin to appear on the surface (image receiving surface) of the image receiving film 1, causing ink loss. This is because it becomes too flexible and the flexibility becomes poor, and it is difficult to make the image receiving film 1 surely follow the curved surface of the adherend. Since the image receiving film 1 is made of polyvinyl chloride having excellent weather resistance, it can sufficiently withstand outdoor use.

The pressure-sensitive adhesive layer 2 may be an acrylic pressure-sensitive adhesive that is widely used for this type of pressure-sensitive adhesive film, but is not limited to this.

The support 3 is made of release paper made of high-quality paper or glassine paper or a resin film typified by polyester or polypropylene.
When the support 3 is a release paper, one having a basis weight of 50 g / m ² or less is used. In the case where the support 3 is a resin film, one having a surface roughness of at least 20 μm or less on the surface in contact with the pressure-sensitive adhesive layer 2 is used. The reason is that the release paper has a basis weight of more than 50 g / m ² , or the surface roughness of the surface of the resin film that comes into contact with the pressure-sensitive adhesive layer 2 is 20 μm.
m, it is difficult for the pressure of the print head during thermal transfer printing to be evenly transmitted to the image receiving film 1, and the print head cannot sufficiently press the convex portion on the surface of the image receiving film 1 so that the ink is reliably transferred to the concave portion. This is because it becomes difficult to cause ink loss. If the surface of the support 3 that is not in contact with the pressure-sensitive adhesive layer 2 also has a surface roughness of 20 μm or less, the support 3 may be wound into a roll at the time of manufacture.
The surface of the image receiving film 1 that does not come into contact with the pressure-sensitive adhesive layer 2 comes into contact with the surface of the image receiving film 1. However, the unevenness of the surface is large. This is because the surface properties deteriorate. FIG. 1 shows a case where the support 3 is release paper.

Further, at least the surface of the support 3 which is in contact with the pressure-sensitive adhesive layer 2 is subjected to a release treatment. The reason is,
This is because the image receiving film 1 is easily peeled off from the support 3 when the image receiving film 1 is attached to the adherend. Also, the surface of the support 3 that is not in contact with the pressure-sensitive adhesive layer 2 is subjected to the release treatment because the support 3 is in close contact with the image receiving film 1 and hardly peels off when it is wound up in a roll and stored for a long period of time. This is to prevent the image receiving film 1 and the support 3 from delamination during rewinding.

Next, examples of the present invention will be shown together with comparative examples.

As shown in Table 1, a resin composition having the following composition A and composition B was used.
Was subjected to calender molding. Longitudinal direction 1.75 kg / mm ² in the hardness of 100% modulus of the image-receiving film 1 obtained in A formulation, transverse direction was 1.50 kg / mm ^2. The hardness of the image receiving film 1 obtained by blending B is 100% modulus, 1.35 kg / mm ^{2 in} the vertical direction, and 1.20 in the horizontal direction.
kg / mm ² . On the other hand, an acrylic pressure-sensitive adhesive was applied to the release agent-coated surfaces of the following three types of supports 3 of C, D, and E, and dried to form a pressure-sensitive adhesive layer 2 having a thickness of 30 μm. The support 3 was laminated with the pressure-sensitive adhesive layer 2 facing the image receiving film 1 to obtain pressure-sensitive adhesive films for thermal transfer printing of Examples 1 and 2 and Comparative Examples 1 to 6, each of which had ink missing and bonded to a curved surface. Was visually evaluated. Table 1 shows the results. Table 1
Among them, the mark ○ indicates good, the mark △ indicates that bad parts are scattered, and the mark × indicates bad as a whole.

<Resin composition of image receiving film 1>

[0028]

<Type of Support 3> C: High-quality paper release paper Basis weight 46 g / m ² Thickness Approximately 50 μm Surface roughness of the surface in contact with the adhesive layer 19.9 μm Surface roughness of the surface not in contact with the adhesive layer 23.6 μm

D: Backside mat-treated PET (PET38 Nippa Co., Ltd.) Thickness 38 μm Surface roughness of the surface in contact with the adhesive layer 3.2 μm Surface roughness of the surface not in contact with the adhesive layer 3.9 μm

E: high-quality paper release paper Basis weight 64 g / m ² Thickness about 100 μm Surface roughness of the surface in contact with the pressure-sensitive adhesive layer 10.2 μm Surface roughness of the surface not in contact with the pressure-sensitive adhesive layer 19.9 μm

[0032]

[Table 1] As is evident from Table 1, in Examples 1 and 2, there was no ink bleeding, and the ink was completely fitted to the curved surface of the adherend, and the bonding property to the curved surface was good.

In Comparative Example 1, ink loss was observed in some places. This is because the release paper as the support 3 has a basis weight of 64 g / m ^2.
And more than 50 g / m ^2, and it is difficult to press the projections on the surface of the image receiving film 1 with the print head.

In Comparative Example 2, as in Comparative Example 1, ink leakage was observed in some places. This is because the thickness of the image receiving film 1 is 6
This is due to the fact that the thickness is less than 70 μm at 0 μm and too thin.

In Comparative Example 3, ink loss frequently occurred.
This is because the thickness of the image receiving film 1 is less than 70 μm at 60 μm and is too thin, and the release paper as the support 3 exceeds 50 g / m ² at the basis weight of 64 g / m ^2, and the projections on the surface of the image receiving film 1 Is difficult to hold down with the print head.

In Comparative Example 4, ink missing was observed in some places. This is because the thickness of the image receiving film 1 is 60 μm and 70 μm.
not less than m, and it is too thin, the vertical direction 1.35 kg / mm ² in the hardness of the image-receiving film 1 of 100% modulus is not less than with lateral 1.20 kg / mm ² to 1.4 kg / mm ^2, soft It is due to passing.

In Comparative Example 5, ink loss frequently occurred.
This is because the thickness of the image receiving film 1 is 60 μm, less than 70 μm, too thin, and the hardness of the image receiving film 1 is 10 μm.
1.35 kg / mm ^{2 in} the vertical direction and 1 in the horizontal direction at 0% modulus.
With 20 kg / mm ² without less than 1.4 kg / mm ^2, and it is too soft, release paper as a support 3 basis weight 64 g / m ²
Is more than 50 g / m ^2, and it is difficult to press the projections on the surface of the image receiving film 1 with the print head.

In Comparative Example 6, ink missing was observed in some places. This longitudinal 1.35 kg / mm ² in the hardness of the image-receiving film 1 of 100% modulus, transverse 1.20 kg / mm ²
Together with less than 1.4 kg / mm ² ,
A support 3 release paper at a basis weight 64g / m ² 50g / m
^This is due to the fact that it is difficult to press the projections on the surface of the image receiving film 1 with the print head.

[0039]

As described above, according to the present invention,
A polyvinyl chloride film is adopted as an image receiving film of the adhesive film for thermal transfer printing, the hardness is set to a hardness corresponding to 1.4 to 4 kg / mm ² with a 100% modulus, and the thickness is set to 70 to 150 μm. Further, the weight of the support is 5
It is made of a release paper of 0 g / m ² or less, or the support is made of a resin film having at least a surface roughness of 20 μm or less in contact with the pressure-sensitive adhesive layer. Thus, it is possible to reliably follow the curved surface of the adherend, and to prevent ink loss by preventing the influence of the surface roughness of the support from adversely affecting the surface of the image receiving film. In addition, weather resistance can be ensured by the material. In addition, the pressure of the print head during thermal transfer printing can be evenly transmitted to the image receiving film, and the protrusions on the surface of the image receiving film can be pressed down sufficiently by the print head to transfer the ink to the recesses reliably, preventing ink leakage. it can. When the surface roughness of the surface of the support that is not in contact with the pressure-sensitive adhesive layer is set to 20 μm or less,
When wound into a roll during manufacture, the surface of the support that does not come into contact with the pressure-sensitive adhesive layer contacts the surface of the image-receiving film. The effect on the surface can be extremely reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of an adhesive film for thermal transfer printing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image receiving film 2 Adhesive layer 3 Support

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B32B 1/00-35/00 B41M 5/00-5/40

Claims (4)

(57) [Claims] 1. An adhesive film for thermal transfer printing, wherein an adhesive layer is provided on the back surface of an image receiving film on which printing is performed by a thermal transfer method, and a support is provided on the adhesive layer so as to be releasable. The film is made of a polyvinyl chloride film and has a hardness of 1.4 to 4 kg / mm with a 100% modulus.
Hardness Der corresponding to ² is, and the thickness 70~150μm
Is set to, the support, thermal transfer printing adhesive film characterized Rukoto such a basis weight of 50 g / m ² or less of release paper. 2. An image receiving film to be printed by a thermal transfer method.
A pressure-sensitive adhesive layer is provided on the back of the system, and the support is provided on the pressure-sensitive adhesive layer.
An adhesive film for thermal transfer printing
Te, the image-receiving film, polyvinyl chloride film
And its hardness is 1.4-4 kg / mm with 100% modulus.
Hardness equivalent to ² and thickness of 70 to 150 μm
It is set to, the support surface of the surface in contact with at least a pressure-sensitive adhesive layer
Made of resin film with roughness set to 20μm or less
An adhesive film for thermal transfer printing, characterized in that: 3. The hardness of the image receiving film is determined by adjusting the amount of the plasticizer added in the composition of the image receiving film to 100% of polyvinyl chloride.
thermal transfer printing adhesive film according to claim 1 or 2, wherein the determined by setting 15~35phr in terms of di-2-ethylhexyl phthalate to phr. 4. The support also claim 1, characterized in that surface in contact with at least a pressure-sensitive adhesive layer is release-treated
Is an adhesive film for thermal transfer printing according to 2 .