JP2001232930A - Backprint recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to produce a favorable ink image by a method wherein ink permeability of an ink permeable layer is not impaired even when a backprint recording medium is pressed by a feed roller of a printer and, even when an inked image is observed with transmitted light, no feed roller mark is observed. SOLUTION: In the backprint recording medium, which is produced by forming the porous ink permeable layer 3 made of a filler scattered in a binder resin on an ink absorbing layer 2, which is formed on a transparent base material 1, a resin having a glass transition temperature of 10 deg.C or higher and a shore D hardness at 25 deg.C of 40 or more is used as the binder resin comprising the ink permeable layer 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a back print recording medium.

[0002]

2. Description of the Related Art A back print recording medium is known as a kind of recording medium used in an ink jet recording system. A typical back print recording medium has an ink absorbing layer formed of a resin material capable of absorbing and fixing ink for inkjet recording formed on a transparent base material such as a polyester sheet, and a filler is further provided thereon with a binder resin. It has a structure in which an ink permeable layer having a porous structure dispersed therein is formed (JP-A-10-211763, JP-B-6-71822, etc.). When ink-jet recording is performed on such a back print recording medium, the ink ejected onto the ink-permeable layer penetrates from the surface of the ink-permeable layer to the inside, reaches the ink-absorbing layer, and reaches the ink-absorbing layer. It is absorbed and fixed. Thereby, an ink image is formed on the ink absorbing layer. The formed ink image is observed from the transparent substrate side.

[0003]

However, in the case of the above-mentioned back print recording medium, there is a problem that the coating strength of the ink permeable layer is not sufficient. For this reason, when performing recording on the back print recording medium by the inkjet printer, the porous structure of the ink permeable layer of the portion pressed by the feed roller of the printer is damaged, and the ink permeability of the portion is reduced, There is a problem that the quality of the ink image is reduced. When observing an ink image with transmitted light, a portion where ink permeability is reduced (pressed portion) and a portion where ink permeability is not reduced (portion not pressed)
There was also a difference in the light transmittance between the two, and feed roller marks became noticeable in the ink image.

[0004] This problem can be solved by increasing the content of the binder resin in the ink-permeable layer to improve the strength of the coating film of the ink-permeable layer. And the ink amount required for good image formation is not absorbed by the ink absorbing layer.

According to the present invention, even when the back print recording medium is pressed by the feed roller of the printer, the ink permeability of the ink permeable layer is not impaired, and the trace of the feed roller is observed even when the ink image is observed with the transmitted light. It is an object of the present invention to form a good ink image by preventing the image from being formed.

[0006]

The present inventors have determined that the glass transition temperature of the binder resin and the Shore D hardness are closely related to the ink permeability and the coating strength of the ink-permeable layer of the back print recording medium. And completed the present invention.

That is, the present invention provides a back print recording method in which an ink absorbing layer is formed on a transparent substrate, and a porous ink transmitting layer in which a filler is dispersed in a binder resin is formed on the ink absorbing layer. Provided is a back print recording medium, wherein the binder resin constituting the ink permeable layer has a glass transition temperature of 10 ° C. or higher and a Shore D hardness at 25 ° C. of 40 or higher. Here, the glass transition temperature of the binder resin is preferably 130 ° C. or less, and the Shore D hardness (25 ° C.) is preferably 90 or less.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The back print recording medium of the present invention will be described in detail below.

As shown in FIG. 1, in a back print recording medium 10 of the present invention, an ink absorbing layer 2 is formed on a transparent substrate 1, and an ink transmitting layer 3 is formed on the ink absorbing layer 2. Having a structure. Here, the ink absorption layer 2
This layer forms an ink image in the layer by absorbing and fixing the ink. The ink permeable layer 3 is a layer that allows ink supplied from the outside to pass through the inside of the layer and supplies the ink to the ink absorbing layer 2, and has a porous structure in which a filler is dispersed in a binder resin.

The binder resin constituting the ink permeable layer 3 has a glass transition temperature of 10 ° C. or higher, preferably 25 ° C.
C. or higher and a Shore D hardness at 25 ° C. of 40
Above, preferably more than 50 are used. When the glass transition temperature is lower than 10 ° C., the strength of the coating film of the ink permeable layer 3 is reduced, and a trace of a feed roller is formed on an ink image, which is not preferable. On the other hand, if the Shore D hardness (JIS Z-2246) at 25 ° C. is less than 40, the strength of the coating film of the ink permeable layer 3 is also lowered, and a feed roller mark is formed on the ink image, which is not preferable.

The glass transition temperature of the binder resin is as follows:
If it is too high, the flexibility of the ink permeable layer 3 is lost, so the temperature is preferably 130 ° C. or lower, more preferably 100 ° C. or lower. Further, if the Shore D hardness (25 ° C.) is too high, the ink permeable layer 3 becomes brittle.
More preferably it is 80 or less.

As the binder resin having the above-mentioned properties used in the ink permeable layer 3, polyester resins,
Examples thereof include a polyvinyl alcohol resin, a polyvinyl butyral resin, polyvinyl acetate, styrene butadiene rubber, an acrylic resin, an acrylic emulsion, and a polyamide resin. Among them, it is preferable to use a polyester resin from the viewpoint of low ink absorption, high coating film strength, and high flexibility.

The filler used in the ink permeable layer 3 includes silica, alumina, talc, calcium carbonate, plastic fine particles and the like. Among them, it is preferable to use silica because of high whiteness and chemical stability.

If the size of the filler is too small, the viscosity of the coating solution increases, and the strength of the coating film decreases. If the size of the filler is too large, the filler sediments in the coating solution and the appearance of the coating film deteriorates, and the image quality also decreases. Since it decreases, it is preferably 0.5 to 30 μm.

In consideration of the ink permeability and the strength of the coating film, the amount of the binder resin and filler in the ink permeable layer 3 is 5 parts per 100 parts by weight of the filler.
A mixing ratio of 200 parts by weight is preferable.

Various additives (for example, a whitening agent) used in the ink-permeable layer of the conventional back print recording medium can be added to the ink-permeable layer 3 as needed.

The thickness of the ink permeable layer 3 is not particularly limited, but is generally 5 to 30 μm.

The ink absorbing layer 2 can have the same structure as the ink absorbing layer of the conventional back print recording medium, and includes, for example, a water-soluble polyester resin, a polyvinylpyrrolidone resin, a polyvinyl alcohol-based resin, polyurethane, polyvinyl acetal, A film formed of an ethylene-vinyl acetate copolymer, an acrylic resin, or the like can be used.

The ink absorbing layer 2 may contain various additives (for example, a whitening agent) used in the ink absorbing layer of the conventional back print recording medium, if necessary.

The thickness of the ink absorbing layer 2 is not particularly limited, but is generally 5 to 30 μm.

The transparent substrate 1 can have the same structure as the transparent substrate of a conventional back print recording medium.
For example, films of polyester, polyethylene, polypropylene, polyamide, vinyl chloride, polycarbonate and the like can be mentioned.

The thickness of the transparent substrate 1 is not particularly limited, but is generally from 10 to 500 μm.

The back print recording medium 10 of the present invention
It can be manufactured by an ordinary method. For example, transparent substrate 1
A coating liquid obtained by dissolving the resin for the ink absorbing layer in an appropriate solvent is coated on a known coating device such as a bar coater or a comma coater, and dried to form the ink absorbing layer 2. A coating liquid obtained by uniformly mixing a binder resin for an ink permeable layer and a filler together with a suitable solvent on the top thereof is coated with a known coating device and dried to form the ink permeable layer 3, thereby producing the ink permeable layer 3. Can be.

The above-described back print recording medium of the present invention can be preferably applied to an ink jet recording method, but can also be used in other recording methods using a recording liquid. For example, it can be used in a recording method using a fountain pen, a felt pen, a pen plotter and the like.

[0025]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to examples.

Examples 1 to 7 and Comparative Examples 1 to 3 (Formation of ink-absorbing layer) 100 μm thick transparent polyester film (Cosmoshine A4100, manufactured by Toyobo Co., Ltd.)
Then, the coating liquid for the ink absorbing layer prepared by stirring the components in Table 1 with a jar mill for 3 hours using a bar coater.
The composition was applied to a dry thickness of 15 μm and dried in a hot air circulating furnace at 120 ° C. for 3 minutes to form an ink absorbing layer.

[0027]

[Table 1] Ingredients Parts by weight Water-soluble polyester resin 32.7 (NS-122L, manufactured by Takamatsu Yushi Co., Ltd.) Polyvinylpyrrolidone 2.1 (Rubiscol K-90, manufactured by BASF) Ion-exchanged water 29 Aluminum hydroxide (H42, manufactured by Showa Denko) 3

(Formation of ink permeable layer) Solvents in the components shown in Tables 2 and 3 were stirred with a dissolver, and the following polyester resins A to G were added thereto, and the mixture was further stirred for 2 hours. Is dissolved, silica (Mizukasil P)
-527, manufactured by Mizusawa Chemical Co., Ltd .; average particle size 1.6 μm, specific surface area 55 m ² / g; oil absorption 130), and stirred for 1 hour to prepare a coating liquid for an ink permeable layer. This coating liquid for an ink permeable layer is applied to the previously formed ink absorption layer with a Meyer bar so as to have a dry thickness of 15 μm, and dried in a hot air circulation furnace at 120 ° C. for 3 minutes to transmit the ink. A layer was formed. Thus, a back print recording medium was obtained.

Polyester resin A: Number average molecular weight
70,000, Shore D hardness (25 ° C.) = 80; Glass transition temperature = 65.8 ° C. Polyester resin B: Number average molecular weight 22,000, Shore D hardness (25 ° C.) = 20; Glass transition temperature = −9. 4 ° C. Polyester resin C: Number average molecular weight 20,000, Shore D hardness (25 ° C.) = 70; Glass transition temperature = 75 ° C. Polyester resin D: Number average molecular weight 15,000, Shore D hardness (25 ° C.) = 70; Glass transition temperature = 65 ° C. Polyester resin E: number average molecular weight: 20,000, Shore D hardness (25 ° C.) = 70; glass transition temperature = 45 ° C. Polyester resin F: number average molecular weight: 30,000, Shore D hardness ( Polyester resin G: number average molecular weight 25,000, Shore D hardness (25 ° C.) = 33; glass transition temperature = 5 ° C.

The results obtained by measuring the Shore D hardness (25 ° C.) and the glass transition temperature of the used polyester resin as described below are shown in Tables 2 and 3.

(Shore D hardness) ME of polyester resin
A K solution (solid content = 50%) was prepared, placed in an aluminum dish coated with a release agent, and placed in an oven at 120 ° C. for 24 hours.
After drying for a time, a polyester resin plate was prepared. The Shore D hardness of the obtained polyester resin plate was measured according to JIS Z-2246. When a plurality of polyester resins were used, Shore D hardness was measured using a polyester resin plate similarly prepared from mixed polyester resins having the compounding ratios shown in Tables 2 and 3.

(Glass Transition Temperature) A part of the polyester resin plate whose Shore D hardness was measured was taken as a test sample, and its glass transition temperature was measured by a differential scanning calorimeter (DSC62).
00, manufactured by Seiko Instruments Inc.).

[0033]

Table 2 (parts by weight) Example Comparative Example Component 1 12 3 12 Silica 30 30 30 30 30 Polyester resin (binder resin) A 30 21 159 -B 915 21 30 (Shore D hardness 80 62 50 38) 20) (Glass transition temperature (° C) 65.8 41.2 23.1 -4.7 -9.4) Methyl ethyl ketone 112 112 112 112 112 112 Cyclohexanone 28 28 28 28 28 Total 200 200 200 200 200 Solid content (%) 30 30 30 30 30

[0034]

(Table 3) (parts by weight) Example Comparative Example Component 4 5 6 7 3 Silica 30 30 30 30 30 Polyester resin (binder resin) C 30----D-30---E--30--F- −− 30 − G − − − − − 30 (Shore D hardness 70 70 70 60 33) (Glass transition temperature (° C.) 75 65 45 355) Methyl ethyl ketone 112 112 112 112 112 112 Cyclohexanone 28 28 28 28 28 Total 200 200 200 200 200 200 Solid content (%) 30 30 30 30 30

(Print Evaluation) Examples 1 to 7 and Comparative Examples 1 to
Each of the back print recording media obtained in Step 3 was cut into A4 size, and a test pattern having a resolution of 720 dpi was printed in four passes with an ink jet printer (FJ-40, manufactured by Roland Corporation) in four passes. The printed image was visually observed, and the quality of the printed image was visually observed.

As a result, the back print recording media of Examples 1 to 7 using a polyester resin having a Shore D hardness (25 ° C.) of 40 or more and a glass transition temperature of 10 ° C. or more as a binder resin of the ink permeable layer. No trace of the feed roller was observed. Moreover, the image quality formed in the portion sandwiched between the feed rollers is equal to the image quality formed in the portion not sandwiched between the feed rollers.
A good image was formed as a whole.

On the other hand, in the case of the back print recording media of Comparative Examples 1 to 3 having a Shore D hardness (25 ° C.) of less than 40 and a glass transition temperature of less than 10 ° C., traces of the feed roller were observed, and The sharpness was impaired. When the back print recording medium was observed with transmitted light, a strip-shaped mottled pattern was observed even in an unprinted portion because the light transmittance of the feed roller trace was reduced.

[0038]

According to the present invention, even when pressure is applied to the back print recording medium by the feed roller of the printer, the ink permeability of the ink permeable layer is not impaired, and the ink image is observed with transmitted light. However, a good ink image can be formed by preventing the trace of the feed roller from being observed.

[Brief description of the drawings]

FIG. 1 is a sectional view of a back print recording medium of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Transparent base material, 2 ... Ink absorption layer, 3 ... Ink transmission layer,
10. Back print recording medium

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hideaki Takahashi 12-3 Satsukicho, Kanuma City, Tochigi Prefecture Sony Chemical Corporation F-term (reference) 2H086 BA14 BA15 BA19 BA34 BA41

Claims (3)

[Claims] An ink absorbing layer is formed on a transparent substrate,
In a back print recording medium in which a porous ink permeable layer in which a filler is dispersed in a binder resin is formed on the ink absorbing layer, the binder resin constituting the ink permeable layer has a glass transition temperature of 10 ° C. or more. And 25
A back print recording medium having a Shore D hardness at 40C of 40 or more. 2. The back print recording medium according to claim 1, wherein the binder resin constituting the ink permeable layer has a glass transition temperature of 130 ° C. or less and a Shore D hardness at 25 ° C. of 90 or less. 3. The back print recording medium according to claim 1, wherein the binder resin constituting the ink permeable layer is a polyester resin.