JP2013049200A - Heat-shrinkable film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a heat-shrinkable film that forms desired characters and patterns or the like with less looseness and warpage in conveyance.SOLUTION: Gurley rigidity of the heat-shrinkable film 10 in a heat-shrinking direction MD is over 0.85 mN, so the film is hardly warped and loosened in a conveyance direction TD. Accordingly, an almost uniform conveyance speed is achieved, which forms the desired characters and patterns or the like.

Description

  The present invention relates to a heat-shrinkable film including a liquid receiving layer that receives a liquid that is transported by a liquid ejecting apparatus and ejected from a liquid ejecting head mounted on the liquid ejecting apparatus.

A heat-shrinkable film is known as a packaging material for articles. As a heat-shrinkable film, a film having a liquid-receptive layer formed on a heat-shrinkable substrate is known. For example, a liquid ejecting head in which ink droplets as a liquid are mounted on an ink jet printer as a liquid ejecting apparatus The ink-jet head serves as an ink receiving layer that is a liquid receiving layer to form characters, patterns, and the like that combine colors. The heat-shrinkable film shrinks and adheres to the article by applying heat, and forms the appearance together with the shape of the article. Here, in order to make use of the shape of the article and suppress an increase in weight, a thin heat-shrinkable substrate is preferable, and a heat-shrinkable substrate having a thickness of 60 μm or less is used.
Inkjet printers can be easily changed in comparison with screen printing, etc., according to commands from computers, etc., for sample preparation, proof printing, production of small quantities of articles, etc. Is suitable.
As a heat-shrinkable film having a liquid receptive layer, a shrink film in which a receptive layer as a liquid receptive layer is provided on a resin film having a heat-shrink performance of about 20 to 150 μm is known (for example, Patent Documents). 1).

JP 2006-178352 A

However, a heat-shrinkable film using a heat-shrinkable base material having a thickness of 60 μm or less has low rigidity, so that sagging occurs in the transport direction during transport or warpage occurs due to shrinkage of the liquid receiving layer. .
The sagging causes unevenness in the conveyance speed and makes it difficult to form a desired character or pattern. In addition, when warping occurs, film clogging, liquid jet head and heat shrinkable film come into contact, or the distance between the liquid jet head and heat shrinkable film varies, forming desired characters, patterns, etc. Becomes difficult.
Furthermore, the heat-shrinkable film undergoes natural shrinkage during transportation and storage, changes in dimensions and wrinkles, and makes it difficult to form desired characters and patterns.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  [Application Example 1] A heat-shrinkable film according to this application example is a roll wound in the heat-shrink direction, conveyed in the heat-shrink direction by a liquid ejecting apparatus, and from a liquid ejecting head mounted on the liquid ejecting apparatus. A heat-shrinkable film comprising a liquid-receiving layer that receives a liquid to be jetted, the heat-shrinkable substrate comprising polyethylene terephthalate having a thickness of 10 μm or more and 60 μm or less on which the liquid-receiving layer is formed, The Gurley rigidity in the heat shrink direction when six shrink films are stacked is 0.85 mN or more.

According to this application example, since the Gurley stiffness in the heat shrink direction of the heat shrinkable film is 0.85 mN or more, when the film is transported in the heat shrink direction by the liquid ejecting apparatus, it is difficult to bend in the transport direction. Is less likely to sag. Therefore, unevenness in the conveyance speed hardly occurs, and desired characters, patterns, and the like can be formed.
Further, since the thickness of the heat-shrinkable substrate containing polyethylene terephthalate is 10 μm or more, it is easy to handle with little deformation during handling, and since it is 60 μm or less, the shape of the article can be utilized without being conspicuous as a packaging material for the article.
Further, when the heat-shrinkable film is pulled out from the roll and transported by the liquid ejecting apparatus, it is pulled out in the heat-shrinking direction, so that it is transported in the heat-shrinking direction, is not easily bent in the transporting direction, and is slack in the transporting direction Hard to occur. Therefore, unevenness in the conveyance speed hardly occurs, and desired characters, patterns, and the like can be formed.
Further, when the heat-shrinkable film is pulled out from the roll and conveyed, a force is applied in the heat-shrink direction. Compared to the case where force is applied in the direction perpendicular to the heat shrink direction, the heat shrink film is less likely to tear when force is applied in the heat shrink direction, so the heat shrink direction is perpendicular to the transport direction. Compared to existing films, the film is less likely to tear.

Application Example 2 In the heat-shrinkable film described in the above application example, it is preferable that the maximum heat shrinkage rate in the heat-shrink direction of the heat-shrinkable substrate is 20% or more and 55% or less.
In this application example, since the maximum heat shrinkage rate in the heat shrink direction is 20% or more, the heat-shrinkable film can be heated and shrunk to be in close contact with the article. There is little natural shrinkage. The maximum heat shrinkage was obtained from the size of the heat-shrinkable film after heating with respect to the size of the heat-shrinkable film before heating when shrinking as much as possible under sufficient temperature and humidity conditions. It is a contraction rate.

Application Example 3 In the heat-shrinkable film described in the application example, it is preferable that the liquid receiving layer includes a skeleton made of at least one of polyurethane resin and acrylic resin.
In this application example, at least one of polyurethane resin or acrylic resin is included in the liquid receptive layer to form a skeleton, so that the liquid receptive layer is less likely to expand and contract due to the entry and exit of liquid solvent and surrounding water, and heat The shrinkable film is less likely to warp. Therefore, the heat-shrinkable film is difficult to contact the liquid jet head.

Application Example 4 The heat-shrinkable film described in the application example described above uses a sheet-like test piece having a square surface with a side of 200 mm, and the square surface of the heat-shrinkable base material is directed to a plane. The sled is the average value of the heights of the four corners of the test piece after being left for 24 hours in an environment of temperature 27 ° C and humidity 65%, then transferred to an environment of temperature 18 ° C and humidity 35% and left for 5 minutes. The amount is preferably 0 mm or more and 50 mm or less.
In this application example, since the warpage amount is 0 mm or more and 50 mm or less, film clogging or contact between the liquid ejecting head that ejects the liquid and the heat-shrinkable film is reduced, and the liquid ejecting head and the heat-shrinkable film are Variations in spacing are reduced, and desired characters and patterns can be formed.
If the amount of warpage is greater than 50 mm, it is difficult to flatten the heat-shrinkable film even if an attempt is made to suck and flatten the heat-shrinkable film.
Here, the square includes a shape deviated from the square due to the creation accuracy at the time of creating the test piece.

Application Example 5 In the heat-shrinkable film described in the application example, it is preferable that the thickness of the liquid receiving layer is 10 μm or more and 50 μm or less.
In this application example, by setting the thickness of the liquid receiving layer to 10 μm or more, while ensuring the function of absorbing the liquid as the liquid receiving layer, the followability to the heat-shrinkable base material is set to 50 μm or less. Since it can be ensured, inhibition of shrinkage is suppressed, and peeling between the liquid receiving layer and the heat-shrinkable substrate is also suppressed. In addition, the time required for drying at the time of forming the liquid receiving layer can be reduced, and the amount of material used for forming the liquid receiving layer can be reduced, thereby reducing the cost.
Furthermore, the transparency of a liquid receiving layer is ensured by the thickness of a liquid receiving layer being 50 micrometers or less.

1 is an overall perspective view of an ink jet printer. 1 is a schematic sectional view of an ink jet printer. Sectional drawing of a heat-shrinkable film. The figure which shows the Gurley rigidity in the conveyance direction TD which is a roll drawing-out direction. The figure which shows the Gurley rigidity in direction CD orthogonal to the pulling-out direction of a roll.

Hereinafter, embodiments will be described with reference to the drawings.
Hereinafter, the heat-shrinkable film 10 concerning embodiment of this invention is demonstrated with reference to drawings. In the following drawings, the scale of each layer and each member is different from the actual scale so that each layer and each member can be recognized.
The ink jet printer 1 as a liquid ejecting apparatus ejects ink such as yellow (Y), magenta (M), cyan (C), and black (K) while conveying the heat-shrinkable film 10, An apparatus for forming letters, patterns, etc. on the heat-shrinkable film 10. As the inkjet method, for example, a piezoelectric method, a thermal jet method, or the like can be used.

FIG. 1 is an overall perspective view of the ink jet printer 1. In the figure, the installation surface of the ink jet printer 1 is the XY plane, the direction in which the transport direction TD of the heat-shrinkable film 10 is projected onto the XY plane is the X direction, the direction orthogonal to the X direction is the Y direction, The direction orthogonal to the XY plane is shown as the Z direction. If the XY plane is a horizontal plane, the Z direction is the vertical direction.
In FIG. 2, the schematic sectional drawing which cut | disconnected the inkjet type printer 1 by the XZ plane was shown.

1 and 2, the ink jet printer 1 includes an apparatus main body 2 and a support base 3 that supports the apparatus main body 2 from below.
In the apparatus main body 2, a platen 4 that supports the heat-shrinkable film 10 is disposed along the transport direction TD of the heat-shrinkable film 10. The heat-shrinkable film 10 is wound into a roll, pulled out from the roll by a transport mechanism (not shown), and transported on the platen 4 along the transport direction TD by the driven roller 8.

In the embodiment, the platen 4 includes a first platen 41, a second platen 42, and a third platen 43 that are inclined with respect to the XY plane in order from the roll side of the heat-shrinkable film 10. The 1st platen 41, the 2nd platen 42, and the 3rd platen 43 are provided continuously, and the angle with respect to an XY plane becomes large as it distances from the roll of heat contractible film 10.
The platen 4 may be provided in parallel with the XY plane or the YZ plane, and the platen 4 may include a suction device for bringing the heat-shrinkable film 10 into close contact with the platen 4. As the angle of the platen 4 with respect to the XY plane is larger and the inclination is steeper, the heat-shrinkable film 10 and the platen 4 are more easily separated from each other, and a suction device is required.

  A bar-shaped guide rail 5 is provided at a position facing the platen 4 across the heat-shrinkable film 10 and in the Y direction, which is the main scanning direction orthogonal to the transport direction TD of the apparatus body 2. A carriage 6 is supported on the guide rail 5. The carriage 6 is reciprocally driven in the Y direction, which is the main scanning direction of the apparatus body 2, along the guide rail 5 by a driving mechanism (not shown).

  The carriage 6 has an ink jet head 7 as a liquid ejecting head facing the heat shrinkable film 10. In addition, an ink cartridge (not shown) for supplying ink to the ink jet head 7 is mounted on the carriage 6.

  The heat-shrinkable film 10 is conveyed in the conveying direction TD along the platen 4, and characters, patterns, etc. are formed by ink ejected from the ink jet head 7 that moves in the main scanning direction. Paper.

FIG. 3 shows a cross-sectional view of the heat-shrinkable film 10.
In FIG. 3, the heat-shrinkable film 10 includes a heat-shrinkable base material 11 and an ink receiving layer 12 as a liquid receiving layer.
The heat-shrinkable substrate 11 is a substrate having the sheet length direction as the heat-shrink direction MD. Here, the maximum heat shrinkage rate in the heat shrink direction MD is preferably 20% or more and 55% or less.
The heat-shrinkable film 10 is a roll wound in the heat-shrink direction MD, and the transport direction TD of the heat-shrinkable film 10 and the heat-shrink direction MD are in the same direction (see FIG. 1). The heat-shrinkable film 10 contains polyethylene terephthalate.
The thickness of the heat-shrinkable substrate 11 is preferably 10 μm or more and 60 μm or less.

The ink receiving layer 12 receives and fixes ink. The ink receiving layer 12 includes a skeleton made of at least one of polyurethane resin or acrylic resin.
The thickness of the ink receiving layer 12 is preferably 10 μm or more and 50 μm or less.

  In FIG. 1, the heat-shrinkable film 10 is conveyed in the heat-shrink direction MD with the ink receiving layer 12 facing the ink-jet head 7 and receives ink ejected from the ink-jet head 7.

Hereinafter, the heat-shrinkable film 10 according to the embodiment will be described in detail by way of examples and comparative examples.
(Example)
As the heat-shrinkable substrate 11, a low-shrinkage type 45 μm-thick polyethylene terephthalate film (Bonset (registered trademark) PTRN47B manufactured by C-I Kasei Co., Ltd.) was used. The heat-shrinkable base material 11 contracts in the transport direction TD (roll drawing direction).
As a method for producing a low shrinkage type 45 μm thick polyethylene terephthalate film roll that shrinks in the transport direction TD, the film is drawn from the roll of non-heat-shrinkable polyethylene terephthalate film while being heated and stretched in the drawing direction. There is a method of rapidly cooling and winding up again on a roll.
The ink receiving layer 12 was formed by applying Pateracol (registered trademark) EG-4X manufactured by DIC Corporation on the heat-shrinkable substrate 11 and then drying. The thickness after drying was 20 μm.
The heat-shrinkable film 10 in the examples had a maximum shrinkage of 50.5% (immersed in hot water at 100 ° C. for 30 seconds). For example, when heated at a temperature of 80 ° C. and a humidity of 50%, the heat shrinkage rate obtained from the size of the heat-shrinkable film 10 after heating with respect to the size of the heat-shrinkable film 10 before heating was 33%. . Hereinafter, the heat shrinkage rate is a shrinkage rate obtained from the size of the heat-shrinkable film 10 after heating with respect to the size of the heat-shrinkable film 10 before heating when heated at a temperature of 80 ° C. and a humidity of 50%.
(Comparative Example 1)
The film of only the heat-shrinkable substrate 11 in the examples was set as Comparative Example 1. The maximum heat shrinkage rate was 50.5% (immersion in hot water at 100 ° C. for 30 seconds), and the heat shrinkage rate was 33%.
(Comparative Example 2)
Shrink film (model number: LX-18s) manufactured by Mitsubishi Plastics Co., Ltd., a film that heat shrinks in the direction CD perpendicular to the transport direction TD (roll pull-out direction). Dipping), the thermal shrinkage is 52%. The ink receiving layer 12 is not formed.
(Comparative Example 3)
Shrink film (model number: S7042) manufactured by Toyobo Co., Ltd., a film that heat-shrinks in the direction CD perpendicular to the transport direction TD (roll pull-out direction), with a maximum heat shrinkage of 60% (soaked in 100 ° C hot water for 10 seconds) The heat shrinkage rate is 41%. The ink receiving layer 12 is not formed.
The films of Comparative Example 2 and Comparative Example 3 are conveyed in a direction orthogonal to the direction CD, which is the heat shrink direction.

FIG. 4 is a diagram illustrating the Gurley rigidity in the transport direction TD (the heat shrinkage direction MD in the example and the comparative example 1) that is the roll pull-out direction.
FIG. 5 is a diagram showing Gurley rigidity in a direction CD (heat shrinkage direction CD in Comparative Example 2 and Comparative Example 3) orthogonal to the roll pull-out direction.

The Gurley stiffness was measured using six films stacked and using a Gurley Stiffness Tester (model number K-105245).
The measurement environment was a temperature of 26 ° C. and a humidity of 50%. The sample size was a sheet-like strip having a square surface with a side of 2.54 cm, an evaluation weight of 25 g, and a weight axial distance of 10.16 cm.

The conveyance failure was evaluated using MAXART (registered trademark) PX-W8000 manufactured by Seiko Epson Corporation as the ink jet printer 1. The PX-W8000 has a suction device on the platen.
A case where the film was able to be transported without sagging was evaluated as ◯, and a case where sagging occurred in the film and the transport speed was uneven, making it difficult to form a desired character, pattern, etc. Table 1 shows the evaluation results of Examples and Comparative Examples.

(Environmental change test)
The heat-shrinkable film 10 was cut into a sheet having a square surface with a side of 200 mm to obtain a test piece.
Place the square surface of the heat-shrinkable base material 11 of the test piece facing a flat surface, leave it for 24 hours in an environment with a temperature of 27 ° C. and a humidity of 65%, move to an environment with a temperature of 18 ° C. and a humidity of 35%, and leave it for 5 minutes. The average value of the heights of the four corners of the test piece after this was taken as the amount of warpage.

The environmental change test was performed according to Example, Comparative Example 4 and Comparative Example 5.
(Comparative Example 4)
The ink receiving layer 12 of the example was prepared by using a cationized modified polyvinyl alcohol instead of Pateracol (registered trademark) EG-4X manufactured by DIC Corporation as Comparative Example 4.
(Comparative Example 5)
The shrink film IJ Clear T made by Piqua Co., Ltd., provided with the ink receiving layer 12 of the example, was designated as Comparative Example 5.

(result)
While the warpage amount of the example was 0 mm, in Comparative Example 4 and Comparative Example 5, the film was rounded, and it was impossible to measure the warpage amount.
Further, printing was performed using a MAXART (registered trademark) PX-W8000 manufactured by Seiko Epson Corporation with a sample of a roll.
In the examples, there was no film clogging, no contact between the ink jet head 7 and the heat shrinkable film 10, and no variation in the distance between the ink jet head 7 and the heat shrinkable film 10.
On the other hand, in Comparative Example 4 and Comparative Example 5, film clogging, the ink jet head 7 and the heat shrinkable film 10 contact each other, or the interval between the ink jet head 7 and the heat shrinkable film 10 varies, It was difficult to form desired characters and patterns.

As described above, according to the heat-shrinkable film 10 according to the embodiment, the following effects can be obtained.
(1) Since the Gurley rigidity of the heat-shrinkable film 10 in the heat-shrink direction MD is 0.85 mN or more, it is difficult to bend in the transport direction TD when transported by the ink jet printer 1, and the transport direction TD Sagging is unlikely to occur. Therefore, unevenness in the conveyance speed hardly occurs, and desired characters, patterns, and the like can be formed.
Moreover, since the thickness of the heat-shrinkable substrate 11 containing polyethylene terephthalate is 10 μm or more, it is easy to handle with little deformation during handling, and because it is 60 μm or less, the shape of the article is utilized without being too conspicuous as a packaging material for the article. be able to.
Further, when the heat-shrinkable film 10 is pulled out from the roll and transported by the ink jet printer 1, the heat-shrinkable film 10 is pulled out in the heat-shrinking direction MD, so that it is transported in the heat-shrinking direction MD and is not easily bent in the transporting direction TD Sag is less likely to occur with respect to TD. Therefore, unevenness in the conveyance speed hardly occurs, and desired characters, patterns, and the like can be formed.
Further, when the heat-shrinkable film 10 is pulled out and transported, a force is applied in the transport direction TD. The heat-shrinkable film 10 is less susceptible to tearing when a force is applied in the heat shrink direction than when a force is applied in a direction perpendicular to the heat shrink direction, so the heat shrink direction is perpendicular to the transport direction. The film can be made difficult to tear compared to the existing film.

  (2) Since the maximum heat shrinkage rate in the heat shrink direction MD is 20% or more, the heat-shrinkable film 10 can be heated and shrunk to be in close contact with the article. The natural shrinkage of can be reduced.

  (3) Since the ink receiving layer 12 includes at least one of polyurethane resin or acrylic resin and forms a skeleton, the ink receiving layer 12 is less likely to expand and contract due to the entry and exit of ink solvent and surrounding water, and heat Warpage is unlikely to occur in the shrinkable film 10. Therefore, the heat-shrinkable film 10 can be made difficult to contact the ink jet head 7.

(4) Since the amount of warpage is 0 mm or more and 50 mm or less, film clogging and contact between the ink jet head 7 for ejecting ink and the heat shrinkable film 10 can be reduced. The ink jet head 7 and the heat shrinkable film 10 are reduced. Variation in the distance between the two can be reduced, and a desired character, pattern, or the like can be formed.
If the warp amount is larger than 50 mm, even if the heat-shrinkable film 10 is sucked and flattened, it is difficult to flatten the warp force.

(5) By setting the thickness of the ink receiving layer 12 to 10 μm or more, ensuring the function of absorbing the ink as the ink receiving layer 12, and setting the thickness to 50 μm or less, the followability to the heat-shrinkable substrate 11. Therefore, inhibition of shrinkage is suppressed, and peeling between the ink receiving layer 12 and the heat-shrinkable substrate 11 is also suppressed. Further, the time required for drying when forming the ink receiving layer 12 can be suppressed, and the amount of material used for forming the ink receiving layer 12 can also be suppressed, so that the cost can be suppressed.
Furthermore, the transparency of the ink receiving layer 12 can be ensured by setting the thickness of the ink receiving layer 12 to 50 μm or less.

  (6) Since the heat shrinkage rate of the heat-shrinkable film 10 is 50% or less, the natural shrinkage rate is less than 1% even after long-term storage at 30 ° C. Generation of wrinkles is suppressed.

Note that the present invention is not limited to the above-described embodiment, and various modifications and improvements can be added to the above-described embodiment.
For example, the heat-shrinkable film 10 may include a primer layer or an adhesive layer between the heat-shrinkable substrate 11 and the ink receiving layer 12. The primer layer and the adhesive layer improve the adhesion between the heat-shrinkable substrate 11 and the ink receiving layer 12.
Further, in order to improve the adhesion between the heat-shrinkable substrate 11 and the ink receiving layer 12, the heat-shrinkable substrate 11 may be subjected to a surface modification treatment such as corona discharge.

  DESCRIPTION OF SYMBOLS 1 ... Inkjet printer, 2 ... Main body, 3 ... Support stand, 4 ... Platen, 5 ... Guide rail, 6 ... Carriage, 7 ... Inkjet head, 8 ... Driven roller, 9 ... Discharge roller, 10 ... Heat shrink , 11 ... heat-shrinkable substrate, 12 ... ink receiving layer, 41 ... first platen, 42 ... second platen, 43 ... third platen.

Claims (5)

A heat-shrinkable film provided with a liquid receiving layer that receives a liquid ejected from a liquid ejecting head mounted on the liquid ejecting apparatus by a roll wound in the heat shrinking direction and conveyed in the heat shrinking direction by a liquid ejecting apparatus Because
A heat-shrinkable substrate comprising polyethylene terephthalate having a thickness of 10 μm or more and 60 μm or less in which the liquid receiving layer is formed;
The heat-shrinkable film, wherein the Gurley rigidity in the heat-shrink direction when the six heat-shrinkable films are stacked is 0.85 mN or more. In the heat-shrinkable film according to claim 1,
The maximum heat shrinkage rate in the heat shrink direction of the heat shrinkable substrate is
A heat-shrinkable film characterized by being 20% or more and 55% or less. In the heat-shrinkable film according to claim 1 or 2,
The liquid-receptive layer includes a skeleton composed of at least one of a polyurethane resin and an acrylic resin. In the heat-shrinkable film according to claim 3,
Using a sheet-like test piece having a square surface with a side of 200 mm,
Place the square surface of the heat shrinkable substrate facing a plane,
After standing for 24 hours in an environment with a temperature of 27 ° C and a humidity of 65%,
Heat shrinkability, characterized in that the warp amount, which is the average value of the heights of the four corners of the test piece after being transferred to an environment of temperature 18 ° C. and humidity 35% and left for 5 minutes, is 0 mm or more and 50 mm or less. the film. In the heat-shrinkable film according to any one of claims 1 to 4,
The heat-shrinkable film, wherein the liquid receiving layer has a thickness of 10 μm or more and 50 μm or less.

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