JP2002067484A - Ink jet recording medium and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a recording medium which prevents ink from oozing without the lowering of an ink absorbing rate when the ink jet printing is performed and also shows high weatherability, at a high manufacturing efficiency. SOLUTION: An ink receiving layer 12 is formed by thermally molding a thermoplastic polyurethane composition having 30-3,000 wt.% average water absorption power and then is bonded to the surface of a support 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medium (media) used for ink jet recording and a method of manufacturing the same, and more particularly to an ink jet recording medium adapted to obtain an outdoor display by an ink jet printer and a method of manufacturing the same.

[0002]

2. Description of the Related Art Recently, there has been proposed an ink jet recording medium comprising an ink receiving layer made of polyurethane having a high water absorbing property and a support for supporting the ink receiving layer, for the purpose of improving the ink absorbing speed (for example, Japanese Patent Application Laid-Open No. H11-157556). JP-A-9-3
9372 and JP-A-10-291363).

In the recording medium disclosed in Japanese Patent Application Laid-Open No. 9-39372, the ink receiving layer is composed of a water-absorbing urethane polymer and an acrylic polymer having a cationic group. The absorption rate is improved, and the dye fixing property, water resistance, and bleeding resistance are improved by an acrylic polymer having a cationic group. On the other hand, JP-A-10-291363
In the recording medium disclosed in Japanese Patent Application Laid-Open Publication No. H11-107, the ink receiving layer is made of porous hydrophilic polyurethane, so that the water absorption of the ink is high, and the color developability of the ink is improved.

[0004] However, in the former recording medium, when the content of the water-absorbing polyurethane is high, the ink absorption speed is improved, and a good image with little bleeding can be obtained. There are disadvantages that are not suitable for recording media. In addition, the latter recording medium has a drawback that if the water absorption of the polyurethane itself is low, an original image cannot be obtained, or good color developability cannot be obtained.

The inventor of the present invention has proposed that the water-absorbing polyurethane is composed of a composition using an aliphatic or alicyclic polyisocyanate as a raw material, and the water-absorbing polyurethane has a specific range of water absorbing ability, and the water absorbing speed of the ink. (Japanese Patent Application No. 11-252280) has been proposed.

However, this recording medium is manufactured by dissolving and dispersing the main component of the ink receiving layer in an organic solvent to form a coating agent, applying the coating agent to paper or a plastic film by a casting method, and drying. Therefore, the solvent is radiated into the atmosphere, which causes environmentally unfavorable problems such as air pollution and drainage. Further, the coating process has low productivity and cannot be reduced in cost.

[0007]

One of the problems to be solved by the present invention is that it is possible to prevent ink bleeding and obtain an excellent image without lowering the ink absorption speed, and to provide a weather resistant image. An object of the present invention is to provide an ink jet recording medium capable of producing a product excellent in quality at a high production efficiency.

Another problem to be solved by the present invention is to provide a product which can prevent ink bleeding to obtain an excellent image without deteriorating the ink absorption speed and which has excellent weather resistance. An object of the present invention is to provide a method for manufacturing an ink jet recording medium that can be manufactured with high manufacturing efficiency and can be manufactured without deteriorating the environment.

[0009]

One object of the present invention is to provide an ink receiving layer mainly composed of a thermoplastic polyurethane composition having an average water absorption of 30 to 3000% by weight. It is an object of the present invention to provide an ink jet recording medium.

In the first means for solving the problems of the present invention, the ink receiving layer itself is in the form of a film and can be used without a support. It is preferable to form a multi-layer recording medium by adhering to a recording medium. It is preferable that the thermoplastic polyurethane composition of the ink receiving layer further contains 10 to 60% by weight of an inorganic filler, and when a support is used, the support is adhered to the fiber substrate and the fiber substrate. And a thermoplastic resin film formed by heating. In this case, the ink receiving layer is formed on the fiber substrate side of the support. The fiber substrate can be a polyester fiber, and the thermoplastic resin adhered to the fiber substrate can be a polyurethane resin.

A second object of the present invention is to provide a method for producing an ink jet recording medium comprising an ink receiving layer, comprising thermoforming a thermoplastic polyurethane composition having an average water absorption of 30 to 3000% by weight. Accordingly, an object of the present invention is to provide a method for producing an ink jet recording medium, wherein an ink receiving layer is formed by the above method.

In the second means for solving the problems of the present invention, the ink-receiving layer itself is in the form of a film and can be used without a support. It is preferable to form a multi-layer recording medium by adhering to a recording medium. The thermoplastic polyurethane composition of the ink receiving layer preferably further contains 10 to 60% by weight of an inorganic filler, and when a support is used, the support is composed of a fiber base material and a fiber base material. It is preferable that it is composed of a thermoplastic resin film formed in close contact. In this case, the ink receiving layer is formed on the fiber substrate side of the support. The fiber substrate can be a polyester fiber, and the thermoplastic resin adhered to the fiber substrate can be a polyurethane resin.

As described above, the ink receiving layer has a thickness of 30 to 300.
When it has an average water absorption capacity of 0% by weight, the ink absorption speed is high and the absorption capacity is large, so that a clear image can be obtained, and further, it has good water resistance and weather resistance and is suitable for indoor use. Of course, it is suitable as a recording medium for an outdoor display.

Further, since the ink receiving layer is made of thermoplastic polyurethane, it can be manufactured continuously by thermoforming such as extrusion molding, calendering molding or blow molding. Can be provided at low cost, and there is no need to dissolve and disperse the material in an organic solvent, so that the production environment such as air and wastewater does not deteriorate.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the embodiments of the present invention will be described in detail.
As shown in FIG. 1, it is composed of an ink receiving layer 12 and a support 14 that supports the ink receiving layer 12.

The ink receiving layer 12 is made of a thermoplastic polyurethane composition having an average water absorption of 30 to 3000% by weight, preferably 150 to 500% by weight, and the thermoplastic polyurethane composition contains 10 to 60% by weight. Is preferably added. This inorganic filler
It is used to improve or adjust the ink absorption speed of the ink receiving layer 12.

As shown in FIG. 1, the support 14 is formed in the form of a film 14C by adhering a thermoplastic resin 14B to a fiber base 14A. As can be seen from FIG.
The ink receiving layer 12 is formed on the fiber base material 14A of the support 14.
Formed on the side.

(Thermoplastic Polyurethane Composition of Ink Receiving Layer) The thermoplastic polyurethane composition used in the ink receiving layer 12 of the present invention is basically obtained by a polyaddition reaction between a polyol and a polyisocyanate compound. However, it can be obtained by other known methods.

Polyols used in the present invention include polyethylene glycol, polyethylene glycol / polytetramethylene glycol copolymer polyol, polyethylene glycol / polypropylene glycol copolymer polyol, polyethylene glycol adipate, and polyethylene glycol / poly-ε-caprolactone. It is preferable that the terminal group such as a polymer polyol is a hydroxyl group and has hydrophilicity. These polyols can be used alone or in combination of two or more.

The polyisocyanate compound used in the present invention can be an aromatic polyisocyanate, an aliphatic polyisocyanate or an alicyclic polyisocyanate.

Examples of aromatic polyisocyanates include diphenylmethane diisocyanate, paraphenylene diisocyanate, 2-chloro-1,4-phenyl diisocyanate, 2,4-toluene diisocyanate, 2,5
-Toluene diisocyanate, 1,5-naphthalenediisocyanate or derivatives thereof are used.

As the aliphatic polyisocyanate or alicyclic polyisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, xylylene diisocyanate or derivatives thereof are used.

In particular, aliphatic or alicyclic polyisocyanates have high transparency,
It is preferable because the coloring property when exposed to light can be improved, and the yellowing of the ink receiving layer can be prevented and the light resistance can be improved.

When the polyol is reacted with the polyisocyanate for synthesis, a chain extender can be added for the purpose of extending the chain of the water-absorbing polyurethane. Examples of such a chain extender include low molecular weight aliphatic diols such as 1,4-butanediol, 1,6-hexanediol and 2,3-butanediol, and low molecular weights such as glycerin, trimethylolpropane and trimethylethane. Aliphatic triols are used. This helps to improve the transparency and color development of the thermoplastic polyurethane.

(Other additives of the water-absorbing thermoplastic polyurethane composition) The water-absorbing thermoplastic polyurethane resin composition used in the present invention may contain appropriate additives for the purpose of imparting various properties. Inorganic or organic pigments such as silica, calcium carbonate, talc, titanium oxide, alumina, colloidal silica, zeolites, starch, polyvinyl alcohol, methylcellulose,
Polyvinylpyrrolidone, methylcellulose, polystyrene resin, urea resin, acrylic resin, melamine resin, urethane resin, and modified products thereof can be added alone or in combination. Preferably, as already mentioned, the water-absorbing thermoplastic polyurethane resin composition has
It is preferable to add 60% by weight of an inorganic filler such as silica, which has the function of improving or adjusting the ink absorption rate of the ink receiving layer. When the water absorbing ability is high, the moldability is reduced. However, a decrease in the moldability can be suppressed by adding an appropriate additive to the ink receiving layer.

(Water Absorbing Ability of Water Absorbing Thermoplastic Polyurethane Composition) The water absorbing thermoplastic polyurethane resin used in the present invention is used in an amount of 30 to 3000% by weight, preferably 150 to 3,000% by weight.
Those having an average water absorption capacity of 3000% by weight are used. The water absorption capacity is represented by the ratio (B / A) of the weight (A) of the thermoplastic polyurethane resin before water absorption and the weight (B) of the thermoplastic polyurethane resin absorbed up to the limit value. When the water absorption capacity is 30 to 3000% by weight, the ink absorption rate and the absorption capacity of the ink receiving layer are sufficiently high. Therefore, when printed thereon by ink jet, a clear image can be obtained without bleeding of the ink. And good water resistance.

The thermoplastic polyurethane resin has a water absorption capacity of 30.
If the amount is less than 10% by weight, the ink absorption rate and water absorption capacity are low, and a clear image cannot be obtained by ink jet. When the water absorption capacity exceeds 3000% by weight,
The adhesive strength of the ink receiving layer 12 to the support 14 is reduced, and the water resistance is reduced.

(Structure of Support) On the other hand, the fiber base material 14A of the support 14 is preferably a polymer fiber such as polyester, nylon or polyethylene.
Plant fibers such as silk and hemp, animal fibers such as wool, and inorganic fibers such as carbon fiber, glass fiber, and metal fiber may be used, and the fiber is preferably in the form of nonwoven fabric or woven fabric. The thermoplastic resin to be brought into close contact with the fiber base material 14A can be, for example, a thermoplastic polyurethane resin. This thermoplastic resin is formed into a film, and is bonded to the fiber base material 14A in the form of a film. However, the fiber base material 12A may be impregnated into a film form. As can be seen from FIG.
The ink receiving layer 12 is formed on the polyester fiber substrate 12A side of the support.

(Manufacturing Method of Recording Medium) The manufacturing method of the ink jet recording medium of the present invention will be schematically described with reference to FIG. 2. A compound for an ink receiving layer is manufactured by using a water-absorbing thermoplastic polyurethane. A material obtained by dispersing silica in a resin (Step 1) is extruded by a twin-screw extruder (Step 2), and then pelletized and dried to form a compound for an ink receiving layer (Step 2). 3). The molding temperature of the extruder is from 150 to 180 ° C. from the hopper to the nozzle.

On the other hand, a fiber base material such as a polymer fiber and a general-purpose thermoplastic polyurethane resin are prepared (step 4), and the thermoplastic polyurethane resin is adhered to the fiber base material by a known calendering method. A film-like support (base fabric) is manufactured (Step 5). The calender molding temperature is set to 150 ° C. to 180 ° C. during the period from the Banbury mixing process to the end of the calender rolling process.

Finally, the compound for the ink receiving layer is formed into a film by a T-die extruder or a calendering machine, and the ink receiving layer film is bonded to the fiber substrate side of the support to complete the recording medium (step 6). ). The molding temperature of the T-die extruder is 15 from the hopper to the screw.
It is maintained at 0 ° C to 200 ° C, and the molding temperature of the calendering machine is 160 ° C to 180 ° C from Banbury to the calender.
C. is maintained. The thickness of the recording medium is 30 μm to 150
It can be set appropriately within the range of μm.

[0032]

EXAMPLES Some embodiments of the present invention will be described below.
The present invention is not limited to these examples,
The composition and ratio of the components of the composition can be appropriately changed. (Example 1) Tecophilic SP-80A-150 manufactured by Thermedics manufactured from an alicyclic polyisocyanate having a water absorption capacity of 150% as a water-absorbing thermoplastic polyurethane composition. 100
0 g and 400 g of P-50 manufactured by Mizusawa Chemical Industry Co., Ltd. as amorphous silica as an inorganic filler were prepared.
These are mixed so as to disperse P-50 in 80-150 to make a raw material for the ink receiving layer. Then, this raw material is
It is put into a hopper of a screw extruder and extruded, and the molded product is pulverized and pelletized, and dried to prepare a compound for an ink receiving layer. On the other hand, E-585 manufactured by Nippon Miractran Co., Ltd. was formed into a film by a calendering method as a general-purpose thermoplastic polyurethane resin on a fiber base material (base cloth) made of polyester fiber having a thickness of 250 denier, and a 100 μm thick film was formed. A support is prepared. Finally, the compound of the ink-receiving layer is put into a hopper of a T-die extruder to form a 50-μm-thick film-shaped ink-receiving layer. Completed a recording medium having a thickness of 150 μm.

(Example 2) Instead of the water-absorbing thermoplastic polyurethane having a water absorbing capacity of 150% used in Example 1,
Tecgel (Tecgel manufactured by Thermedix Co., Ltd.), also made of alicyclic polyisocyanate and having a water absorption capacity of 500% by weight.
ogel) -500-V, except that a recording medium was manufactured under the same conditions as in Example 1.

(Example 3) Instead of the water-absorbing thermoplastic polyurethane having a water absorbing ability of 150% or 500% used in Examples 1 and 2, an aromatic polyisocyanate is used as a raw material, but the water absorbing ability is 30% by weight. Examples 1 and 2 except that AQ-30 manufactured by Okada Engineering Co., Ltd. was used.
A recording medium was manufactured under the same conditions as described above.

Example 4 The alicyclic polyisocyanate is used as a raw material instead of the water-absorbing thermoplastic polyurethanes having a water absorbing capacity of 150%, 500%, and 30% used in Examples 1 to 3. Was manufactured under the same conditions as in Examples 1 to 3 except that Tecogel 3000 manufactured by Thermedix Co. was used.

(Comparative Example 1) Instead of the water-absorbing thermoplastic polyurethane having a water absorbing capacity of 150%, 500%, 30%, and 3000% used in Examples 1 to 4, an alicyclic polyisocyanate was also used as a raw material. However, a recording medium was manufactured under the same conditions as in Examples 1 to 4 except that SP-60D-20 manufactured by Thermedix having a water absorption capacity of 20% by weight was used.

(Comparative Example 2) Instead of the water-absorbing thermoplastic polyurethane having a water absorbing capacity of 150%, 500%, 30%, and 3000% used in Examples 1 to 4, an alicyclic polyisocyanate was also used as a raw material. However, recording media were manufactured under the same conditions as in Examples 1 to 4 except that E-585 manufactured by Nippon Milatran Co., Ltd. having a water absorption capacity of 0% by weight was used.

The recording medium which is a product of Examples 1 to 4 and Comparative Examples 1 and 2 is provided with a large-sized inkjet plotter NOV manufactured by Encad, Inc., USA.
GO marketed from the company using AJET / PRO
An appropriate image was printed with ink (Graphic Outdoor Ink), and the print results at that time were evaluated for the following characteristics. (1) Ink absorption speed This means that the copy paper is placed on the image surface within one minute after the printing is completed, and the ink adheres to the copy paper after a load of 3.3 kg is left for one minute under a load of 3.3 kg. The condition was observed and evaluated. The results of the evaluation are as follows: ○: no ink adhered to copy paper, △: slight adherence but no significant effect on image, ink considerably adhered to copy paper, affected image Certain items were marked as x. (2) Clarity of Image This was evaluated by observing the shape of a printed dot. The image was evaluated as ○ when there was no bleeding in the image, as Δ when there was bleeding but no problem in use, and as x when there was considerable bleeding and loss of image clarity. (3) Water resistance This is because a recording medium on which an image is recorded is immersed in water for 1 minute, and then naturally dried while being kept vertically in the air. Was evaluated. ○: No peeling of the ink receiving layer and no ink dropping. ○: No peeling of the ink receiving layer, slight ink drop and not affecting the image. △: Large peeling of the ink receiving layer and ink dropping. Certain items were marked as x. (4) Light fastness This was evaluated by irradiating an image for 28 hours using an I-Super UV tester W type (SUV-W1) manufactured by Iwasaki Electric Co., Ltd., and observing the degree of discoloration.も の indicates that the same image as before irradiation was obtained without discoloration of the ink, 、 indicates that the ink had fading in detail but had no practical problem, and x indicates that the ink had fading as a whole. (5) Peeling property This was done by attaching a tape with an acrylic resin-based adhesive to the image surface, applying a load of 500 g for 1 minute, and observing the peeling state of the ink receiving layer and ink drop when the tape was peeled off. Was evaluated. When the ink receiving layer was neither peeled nor ink-dropped, the result was evaluated as ○. When the ink-receiving layer was not peeled and the ink was slightly removed and did not affect the image, the result was rated as Δ. (6) Color development The color development was observed and evaluated while irradiating light from the back side of the image surface.も の indicates bright and vivid color development in detail, △ indicates slight lack of color development, and × indicates no color development.

The results of evaluation of the above characteristics of Examples 1 to 3 and Comparative Examples 1 and 2 are as shown in Table 1 below.

[0040]

[Table 1]

From Table 1 above, the water absorption capacity of the ink receiving layer containing thermoplastic polyurethane as a main component is 30% by weight or more on average.
When the ink is printed on a recording medium by inkjet at 3000% by weight, the ink absorption speed, the sharpness of the image,
It turns out that it is good in all of light resistance, peeling property, and coloring property, or there is no problem in practical use.

The manufacturer may market only the ink receiving layer, and the consumer may use the ink receiving layer as it is, or may attach it to a support and use it. Generally, it is used as it is without a support for indoor use, and is attached to a support for outdoor use.

[0043]

According to the present invention, as described above, the water absorption capacity of the ink receiving layer containing thermoplastic polyurethane as a main component is set to 30% by weight to 3000% by weight on average, so that the ink is printed on the recording medium by inkjet. The ink absorption speed, image clarity, light fastness, peelability and color development are all good or practically acceptable, so recording for large screens, especially for outdoor use, for advertising, etc. Suitable for media.

Further, since the ink receiving layer is made of thermoplastic polyurethane, it can be manufactured continuously by thermoforming, so that the manufacturing efficiency can be improved and the material can be provided at low cost. Does not need to be dissolved and dispersed in an organic solvent, so that the production environment such as air and wastewater does not deteriorate.

[Brief description of the drawings]

FIG. 1 is an enlarged cross-sectional view of an ink jet recording medium according to the present invention.

FIG. 2 is a schematic process diagram showing an outline of a method of manufacturing an ink jet recording medium according to the present invention in the order of processes.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 inkjet recording medium 12 ink receiving layer 14 support 14A fiber base material 14B thermoplastic resin 14C film

Claims (10)

[Claims] 1. An ink jet recording medium comprising an ink receiving layer mainly composed of a thermoplastic polyurethane composition having an average water absorption of 30 to 3000% by weight. 2. An ink-jet printing method comprising: an ink receiving layer mainly composed of a thermoplastic polyurethane composition having an average water absorption of 30 to 3000% by weight; and a support for supporting the ink receiving layer. recoding media. 3. The ink jet recording medium according to claim 1, wherein the ink receiving layer further contains 10 to 60% by weight of an inorganic filler in the thermoplastic polyurethane composition. recoding media. 4. The ink jet recording medium according to claim 2, wherein the support has a form of a film composed of a fiber base material and a thermoplastic resin formed in close contact with the fiber base material. An inkjet recording medium, wherein the ink receiving layer is formed on the fiber base side of the support. 5. The ink jet recording medium according to claim 4, wherein said fiber base is made of polyester fiber, and said thermoplastic resin is a polyurethane resin. 6. A method for producing an ink jet recording medium comprising an ink receiving layer, comprising 30 to 3000% by weight.
A method for producing an ink jet recording medium, comprising forming the ink receiving layer by subjecting a thermoplastic polyurethane composition having an average water absorbing ability to thermoforming. 7. A method for producing an ink jet recording medium comprising an ink receiving layer and a support for supporting the ink receiving layer, wherein the thermoplastic polyurethane composition having an average water absorption of 30 to 3000% by weight is heat-treated. A method for manufacturing an ink jet recording medium, wherein the ink receiving layer is formed by molding, and the ink receiving layer is adhered to the support. 8. The method for producing an ink jet recording medium according to claim 6, wherein the thermoplastic polyurethane composition of the ink receiving layer further contains 10 to 60% by weight of an inorganic filler. Of producing an inkjet recording medium. 9. The ink jet recording medium according to claim 7, wherein the support comprises a fiber base material and a thermoplastic resin film formed in close contact with the fiber base material, A method for manufacturing an ink jet recording medium, wherein the ink receiving layer is adhered to the fiber substrate side of the support. 10. The method of manufacturing an ink jet recording medium according to claim 9, wherein the fiber base is made of polyester fiber, and the thermoplastic resin is
A method for producing an ink jet recording medium, which is a polyurethane resin.