JP2001129951A - Printing sheet and card - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-PVC printing sheet for bringing about no offset even by screen printing under the same conditions as those of printing on a PVC sheet. SOLUTION: The printing sheet comprises a sheet containing a substantially non-crystalline polyester resin as a main component and a foamed layer having an expansion ratio of 1.5 to 3 and a thickness of 10 to 200 μm and laminated on an at least one surface of the sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing sheet and a card suitable for use in plastic cards, underlays, sign panels, etc., which can be subjected to screen printing or the like.

[0002]

2. Description of the Related Art As a material for a plastic card such as a magnetic stripe card and a printing material such as an underlay or a sign panel, a sheet made of a polyvinyl chloride resin (hereinafter referred to as "PVC") has been conventionally used. . For example, a magnetic stripe card is generally formed by stacking two white core sheets having one side printed thereon such that the non-printed sides are opposed to each other so that the non-printed sides face each other, and heat-sealing the sheets with a hot press. It is manufactured by cutting into a card shape with a punching blade. Sheets made of PVC can be mass-produced by a calender method, and are excellent in processability such as printability and heat sealability, and are suitable materials for cards.

However, recently, from the viewpoint of environmental protection, PV
There is a growing need for card sheets made of materials other than C. For example, 30 to 40 mol% of the ethylene glycol component in polyethylene terephthalate is 1,4-
A sheet comprising a non-crystalline polyester resin (trade name “PETG”, manufactured by Eastman Chemical Company) substituted with cyclohexanedimethanol has been proposed. This material has processability close to that of a PVC sheet. For example, when producing a card, the card can be produced using the same equipment as that used to produce a card using a PVC sheet. ing.

However, when screen printing is performed on a core sheet of such a material using the same ink as that used for printing on a PVC sheet under the same conditions, the ink dries very slowly, so that the ink immediately after the drying step is completed. When the sheets are stacked, there is a problem that so-called “show-through” tends to occur, in which ink is transferred to the back surface of the sheet above the printing surface.

The show-through that occurs when screen printing is performed on a sheet mainly composed of a substantially non-crystalline polyester resin such as PETG is considered to be due to the following causes. That is, the drying property of a printed sheet is determined by the relationship between the rate of evaporation of the solvent from the sheet surface and the rate of penetration of the solvent into the sheet. When drying under the same conditions using the same ink, the solvent from the sheet surface Is theoretically the same, but the penetration rate into the sheet is different. Cyclohexanone, a slow drying solvent contained in screen printing inks, is absorbed in a short time by a PVC sheet, while it is absorbed by a substantially non-crystalline polyester resin sheet such as PETG. It is unlikely to be swollen and remains on the sheet surface after swelling, so that even after the normal drying step, the concentration of cyclohexanone near the sheet surface is high, and show-through tends to occur.

In order to prevent such show-through, various studies have been made, such as making the drying time longer than when printing on a PVC sheet and changing the solvent composition of the ink. At present, the polyester resin sheet is manufactured with the same equipment as the PVC sheet, and the feasibility is poor. Therefore, a sheet that does not show off even when screen printing is performed under the same conditions as when printing is performed on a PVC sheet has been desired.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a printing apparatus in which the show-through occurs even when screen printing is performed under the same conditions as printing on a PVC sheet. Another object of the present invention is to provide a sheet made of a non-crystalline polyester resin.

[0008]

The printing sheet of the present invention has a sheet mainly composed of a substantially non-crystalline aromatic polyester resin, and at least one surface of the sheet has an expansion ratio. Is 1.5 to 3 times and the thickness is 10 μ
It is characterized in that a foamed layer of m to 200 μm is laminated. Here, the main component of the resin of the foam layer is preferably the same as the main component of the resin of the adjacent sheet or layer. Further, it is preferable that at least one surface of the printing sheet is subjected to a matting process with a 10-point average roughness of 10 μm to 40 μm. Further, the substantially non-crystalline aromatic polyester resin is composed of 30 to 40 of the ethylene glycol component in polyethylene terephthalate.
It can be one obtained by substituting mol% with 1,4-cyclohexanedimethanol. The card of the present invention is characterized in that at least one of the outermost layers is constituted by any one of the printing sheets described above.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The printing sheet of the present invention comprises a sheet mainly composed of a substantially non-crystalline polyester resin and a foamed layer. In the present invention, two or more sheets and two or more sheets are used. May be included, and other sheets and layers may be included as long as the effects of the present invention are not impaired. The foam layer is preferably provided on the surface on which printing is performed, and is preferably laminated on at least one surface of a sheet mainly containing a substantially non-crystalline polyester resin.

In the present invention, the foamed layer has an expansion ratio of 1.
5 to 3 times, and the thickness of the layer needs to be 10 μm to 200 μm. If the expansion ratio is less than 1.5 times,
When silk printing is performed, show-through cannot be completely prevented. If the foaming ratio exceeds 3 times, scratches such as sheet press marks are likely to occur, and the sheet's hand linkability is reduced. This is because, when the printed sheet is pressed, there may be a problem that a drawing such as a pattern is distorted. Further, if the thickness of the foam layer is less than 10 μm, show-through after silk printing cannot be completely prevented, and if it exceeds 200 μm, the handleability of the sheet is reduced.

In the present invention, the main component of the resin in the foam layer is not particularly limited, but is preferably the same as the main component of the resin in the layer adjacent to the foam layer from the viewpoint of the adhesion between the layers. Specifically, when a foamed layer is laminated on the surface of a sheet containing an amorphous polyester-based resin as a main component, the main component of the resin of the foamed layer is preferably an amorphous polyester-based resin. .

In the present invention, the foamed layer is formed as a laminated sheet by co-extruding a foamed layer resin composition containing a foaming agent and a resin composition of an adjacent sheet and / or layer. The cells of the foam layer are formed by foaming the foaming agent when the laminated sheet is formed, and may be closed cells or open cells such as through cells. As the foaming agent, a commonly used foaming agent can be used in an amount usually used, but when the adjacent sheet is made of a resin containing a substantially non-crystalline aromatic polyester-based resin as a main component, It is preferable to use azodicarboxylic amide, barium azodicarboxylate, or the like, and the amount used is preferably 0.2 to 4.0% by weight of the resin composition. Further, an appropriate material can be copolymerized or blended in the foamed layer depending on the application. Further, the foamed layer can be formed by a method of injecting high pressure carbon dioxide gas, nitrogen gas or the like into the molten resin.

In the present invention, the non-printed surface of the printing sheet (hereinafter referred to as the "back surface"), that is, the surface that comes into contact with the printed surface of the adjacent sheet when the printed and dried sheets are stacked. In this case, it is preferable that the matte processing is continuously performed so that a 10-point average roughness (hereinafter, referred to as “Rz”) is 10 μm or more. Backside R
When z is 10 μm or more, drying time after printing is short, and show-through does not occur even after the dried sheets are left standing for a long time. The upper limit of Rz on the back surface is not particularly limited, but when pressing and fusing with another sheet, such as a card or an underlay, air between the sheets cannot be completely removed and air bubbles remain in the product. So as not to
Preferably it is less than about 40 μm. In the present invention, Rz of the surface on which screen printing is performed is not particularly limited, and can be appropriately determined according to the precision of a printed pattern or the like.

In the present invention, the polyester means a dehydration condensate of an aromatic dicarboxylic acid and a diol, and the "substantially non-crystalline polyester" is a so-called copolymerized polyester which is particularly low in crystallinity. , Which does not cause clouding or poor fusion due to crystallization, even when subjected to practically frequently performed thermal processing such as press fusion. Specifically, a non-crystalline polyester resin (trade name “PETG”, manufactured by Eastman Chemical Co., Ltd.) in which 30 to 40 mol% of an ethylene glycol component in polyethylene terephthalate is substituted with 1,4-cyclohexanedimethanol is commercially available. It is mentioned as what can be obtained. Such a material is excellent in workability, physical properties, and the like, and is suitably used in the present invention.

In the present invention, a colorant or a lubricant may be added to each sheet and each layer constituting the printing sheet, if necessary.
Alternatively, a material for improving physical properties such as impact strength and heat resistance can be appropriately added.

In the present invention, cards such as magnetic stripe cards and underlays can be manufactured using the printing sheet of the present invention. Such a card or the like is preferably configured such that the foam layer of the printing sheet serves as a printing surface. The method for manufacturing the card or the like is not particularly limited, and a commonly used method is used. When a card is manufactured from the printing sheet of the present invention, it is preferable that the sheet contains 5 to 30% by weight of titanium oxide. When a card is inserted into a reader / writer, it is generally necessary to have a high degree of shielding near-infrared wavelengths in order to detect the card correctly.
If it is at least% by weight, a sufficient degree of shielding can be obtained. Further, when the content of titanium oxide is 30% by weight or less, problems such as a reduction in workability into a sheet and a reduction in sheet strength do not occur.

[0017]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto. Example 1 P was used as a substantially non-crystalline aromatic polyester resin.
Using ETG6763 (manufactured by Eastman Chemical Company),
A composition composed of 90% by weight of PETG6763 and 10% by weight of titanium oxide and a resin composition of a foamed layer having a composition shown in Table 1 were laminated by coextrusion at a temperature of 230 ° C. to obtain a total thickness. Of 600 μm was prepared. However, the surface roughness (Rz) of the back surface, the thickness of the foamed layer, and the expansion ratio are the values shown in Table 1. These values were obtained by cooling while heating. The surface roughness (Rz) was measured using a stylus type two-dimensional roughness measuring device. Using the same screen printing ink (trade name “VS Screen Ink”, manufactured by Teikoku Ink Mfg. Co., Ltd.) on the front side of the obtained printing sheet, the same ink used for printing the PVC sheet was used. Was screen-printed and dried at 55 ° C. for 20 minutes, and then evaluation of show-through and evaluation of ink adhesion were performed as described below.

Evaluation of show-through: 2 sheets of printing sheet after drying
00 sheets were stacked and left at room temperature for 1 hour, and the state (whether tactile) was evaluated as to whether or not the printed surface of the bottom sheet of the stacked sheets was stuck to the sheet above the stacked sheets. However, those having an evaluation of “3” or more are practically usable as printing sheets. 5 Sheet is easily peeled 4 Slight tack is recognized 3 There is tack, but there is no show-through on the printed surface 2 Partly shows off on the printed surface 1 There is considerable show-through on the printed surface Evaluation of the handleability of the sheet : Evaluation was performed by pressing the dried printing sheet with a finger. The case where no finger depression occurs on the sheet even when the sheet is pressed with a finger is represented by “○”, and the case where the finger depression easily occurs on the sheet is represented by “×”.

Examples 2 to 7, Comparative Examples 1 to 4 In Example 1, except that the composition, thickness and expansion ratio of the foam layer and the surface roughness (Rz) of the back surface were changed as shown in Table 1. A printing sheet was produced in the same manner as in Example 1. However, the expansion ratio and thickness of the foam layer, and the surface roughness (Rz) of the back surface are adjusted by adjusting the extrusion ratio of the two layers, selecting a mat roll having an appropriate surface roughness and passing between the mat rolls. Adjusted by cooling. Then, the evaluation of show-through and the handling property of the printed sheet were performed in the same manner as in Example 1. Table 1 shows the results.
Shown in

[0020]

[Table 1]

As is clear from Table 1, the printing sheets of Examples 1 to 7 of the present invention did not show off and showed good sheet handling properties. On the other hand, the printing sheets of Comparative Examples 1 and 2 had poor handling properties.
The printing sheet of No. was severely show-through, and was unsuitable as a printing sheet. In the above Examples and Comparative Examples, only the sheet having a white sheet is shown.
The same effect was obtained with the transparent sheet. In addition, when a magnetic stripe card was produced using the printing sheets of Examples 1 to 7, no show-through of the ink occurred, and an excellent card could be produced.

[0022]

As described above, the printing sheet of the present invention does not show off the ink even when screen printing is performed under the same conditions as those for screen printing of a PVC sheet, and the printing of a card or the like is not performed. It is suitable as a material.

Continued on the front page F term (reference) 2C005 HA10 JA02 KA70 KB05 2H113 AA03 AA06 BA10 BB08 DA57 4F100 AA21 AK41A AK41B AK42A AK42B BA02 BA03 BA06 BA16 DD07A DD07B DJ01B EJ34A EJ34B EJ40A EJ40B00A

Claims (5)

[Claims] 1. A sheet comprising a substantially non-crystalline aromatic polyester-based resin as a main component, wherein at least one surface of the sheet has an expansion ratio of 1.5 to 3 times, and A printing sheet, wherein a foamed layer having a thickness of 10 μm to 200 μm is laminated. 2. The printing sheet according to claim 1, wherein the main component of the resin of the foam layer is the same as the main component of the resin of the sheet or layer adjacent to the foam layer. 3. The printing according to claim 1, wherein at least one surface of the printing sheet is subjected to a matting process with a 10-point average roughness of 10 μm to 40 μm. Sheet. 4. The substantially non-crystalline aromatic polyester-based resin is obtained by substituting 30 to 40 mol% of an ethylene glycol component in polyethylene terephthalate with 1,4-cyclohexane dimethanol. The printing sheet according to any one of claims 1 to 3, wherein: 5. The method according to claim 1, wherein at least one of the outermost layers is formed.
A card comprising at least one printing sheet selected from the group consisting of: