KR19990005396A - Transparency Film for Inkjet Printers - Google Patents

Abstract

The present invention relates to a transparency film for an inkjet printer, and more particularly, an ink absorbing layer having a two-layer structure consisting of an ink fixing layer and an ink transmitting layer is laminated on one surface of a polyethylene terephthalate base film. By setting the composition of the binder component and the additive of each layer forming the absorbent layer differently to improve the durability, light transmittance and ink absorbency, the undercoat layer is designed directly on the base film so that the ink absorbent layer can increase the adhesive force when adhering to the substrate. The present invention relates to a transparency film which is useful for inkjet printers as well as providing general purpose in various types of inkjet printers, and having excellent ink absorption, color, and image quality.

Description

Transparency Film for Inkjet Printers

The present invention relates to a transparency film for an inkjet printer, and more particularly, an ink absorbing layer having a two-layer structure consisting of an ink fixing layer and an ink transmitting layer is laminated on one surface of a polyethylene terephthalate base film. By setting the composition of the binder component and the additive of each layer forming the absorbent layer differently to improve the durability, light transmittance and ink absorbency, the undercoat layer is designed directly on the base film so that the ink absorbent layer can increase the adhesive force when adhering to the substrate. The present invention relates to a transparency film which is useful for inkjet printers as well as providing general purpose in various types of inkjet printers, and having excellent ink absorption, color, and image quality.

The inkjet printing method is widely used by consumers because of its high output speed, low cost of printers, low maintenance, and the like, and high-resolution images. In addition, inkjet printers have the advantage of using a variety of recording media such as plain paper, specially coated specialty paper, envelopes, and labels.

As another recording medium for inkjet printers, a transparency film has an ink absorbing layer composed of a hydrophilic material on a base film such as hydrophobic cellulose acetate or polyester (e.g. polyethylene terephthalate). It is designed to absorb ink easily. It is mainly used as a presentation tool in overhead projectors, and may be extended to exterior wall decoration, design, and advertising. Accordingly, the transparent film requires a clear color image, excellent light transmittance, and ink absorbing power.

Transparency films for inkjet printers are widely used in developed countries such as Europe and the United States, but are not widely used in Korea. However, given the remarkable penetration rate of inkjet printers and the increasing demand for color expression of consumers, it is expected that it will soon become a popular inkjet printing recording medium in Korea.

The most widely used transparency films for inkjet printers have a coating layer designed to be suitable for an aqueous dye type inkjet printer. For example, a single coating layer consisting of a mixture of a water-soluble binder component such as polyvinyl pyrrolidone and a hydrophilic binder component such as gelatin and polyvinyl alcohol (US Pat. No. 4,503,111, Japanese Patent Application Laid-Open No. 62-214985), or ink Two layers consisting of ink penetrating layer of slightly hydrophilic binder component such as polyvinyl acetate, polyurethane resin, etc. and ink fixing layer of water-soluble and hydrophilic binder component such as polyvinyl pyrrolidone, polyvinyl alcohol, gelatin for fast absorption Coating layers [Japanese Patent Laid-Open No. 61-35278, German Patent No. 3523269] are known. The transparency film including the coating layer described above has some improvement in ink absorption or durability, but the problem of the image printing, that is, the primary density, the light density of mixed colors, the color error, the turbidity, etc., does not improve in actual printer output. There was this. In addition, as inkjet printers are manufactured by various companies due to the diversification of the inkjet printer market, not only the inks used here but also pigment type inks are developed in addition to the existing dye types, so that the conventional transparency films There was a restriction in use.

Accordingly, there is an urgent need for a universal transparency film capable of providing excellent images in various inkjet printing methods and various types of printers.

The present inventors have made great efforts to develop a transparency film having excellent durability and excellent ink absorption and durability even in various types of inkjet printers, and excellent in color and image quality in printing. As a result, we designed a two-layered ink absorbing layer consisting of an ink transmitting layer and an ink fixing layer, and each of these layers uses various additives to supplement the binder component and the physical properties of various types of inkjet printers. By using the silica dispersion dispersed in water, it solved the problem of light transmittance which can be a problem while improving the ink absorption ability and preventing the sticking, and by introducing the aluminum sulfate which has not been used in the prior art, The invention has been completed.

Accordingly, the present invention improves ink absorption and light transmittance at the same time, and can provide a transparent film that can produce a clear image in general, even when printed on various inkjet printers, and exhibits good physical properties even in a pigment type ink. The purpose is.

1 is a cross-sectional view of a transparency film according to the present invention.

Explanation of symbols for main parts of the drawings

1: base film 2: undercoating layer

3: ink absorbing layer 3a: ink fixing layer

3b: ink transmission layer

The invention relates to a transparent film for an inkjet printer, in which an ink fixing layer and an ink transmitting layer are sequentially stacked as an ink absorbing layer on one side of the base film, wherein the ink fixing layer includes a polyvinyl alcohol and a polyvinyl p as a binder component. It is characterized by the fact that it is contained, and the said ink permeable layer contains polyethylene oxide as a binder component.

Referring to the present invention in more detail as follows.

The present invention relates to a transparency film for an inkjet printer in which a two-layered ink absorbing layer each containing a specific binder component and an additive having excellent affinity with an aqueous dye as a main component of the ink is applied to one side of the base film. As a binder component and an additive are introduced into the ink fixing layer and the ink transmitting layer constituting the ink absorbing layer, there is a feature to optimize the physical properties of the transparent film.

The lamination state of the transparent film according to the present invention is illustrated in FIG. 1, which will be described in more detail as follows.

The base film 1 is a hydrophobic polyester having a thickness of about 100 μm that is commonly used in general copiers. Specifically, polyethylene terephthalate is used. Transparent films such as polycarbonate and cellulose acetate are mostly used depending on the use of the transparency. Both can be used.

The ink absorbing layer 3 is composed of an ink fixing layer 3a and an ink transmitting layer 3b. In the ink absorbing layer, the ink fixing layer 3a actually serves to fix the ink on the film, and the ink transmitting layer 3b determines the quick absorption and surface area of the ink. Therefore, the thicker the ink permeable layer is, the slower the rate at which the ink jetted from the nozzle is transferred to the ink fixing layer in which the image is shaped, so that the thickness of the ink transmitting layer must be smaller than that of the ink fixing layer. Physical properties will be better. It is preferable that the transparent film for inkjet printers of this invention is 10-20 micrometers in thickness of an ink fixing layer, and 0.5-5 micrometers in thickness of an ink permeable layer.

As a solvent of the ink absorbing layer composed of the ink fixing layer 3a and the ink transmitting layer 3b, water is generally used. When only water is used alone, drying time is increased after applying the ink absorbing layer. There are disadvantages. Therefore, it is preferable to mix and use the alcohol which evaporates well compared with water in the range which the physical property of a coating liquid does not fall. For example, less than 100 parts by weight of alcohol having 1 to 3 carbon atoms is contained per 100 parts by weight of water.

In addition, the physical properties of the transparent film may vary greatly depending on the kind, molecular weight, and solubility of the binder component used in the ink absorbing layer 3, and these binders may be appropriately used in combination for better physical properties. In addition, since the ink and printing mechanism used in accordance with the printing method of the inkjet printer or the characteristics of each company is different, it is not easy to select a general-purpose binder, and requires a high formulation technology.

In the present invention, polyvinyl alcohol and polyvinyl pyrrolidone are mixed and used in the same amount among the vinyl polymer as the binder component used in the ink fixing layer 3a. 15 weight percent. In the case of polyvinyl alcohol, the cation-modified polyvinyl alcohol whose saponification degree is 86-91 mol% is preferable at the point which absorbs ink quickly. In the case of polyvinyl pyrrolidone, it is preferable to use the thing of the molecular weight 1,000,000-1,500,000 from the point of ink absorption, ink bleeding, and workability at the time of preparation of coating liquid. In addition, the ink fixing layer coating liquid composition optionally contains 10 parts by weight or less of polyethylene oxide and 70 parts by weight or less of silica dispersion in the ink fixing layer 3a with respect to 100 parts by weight of the binder component together with the vinyl polymer. You can also improve.

This improves the light transmittance of the transparent film, prevents bleeding, and maintains the initial light density after printing over time to maintain excellent color and image persistence.

In the present invention, polyethylene oxide is used as the binder component used in the ink transmitting layer 3b, which is contained in the composition of the ink transmitting layer coating liquid at 2 to 10% by weight. As polyethylene oxide, the molecular weight is 300,000 to 500,000, and the coating surface becomes smooth during coating, so that even when a pigment type ink is used, the light density is improved to maintain color and image stability and durability.

In addition, the ink permeable layer composition contains a silica dispersion, a fluorescent dye, and a sulfide compound.

Conventionally, inorganic fillers (eg, silica, titanium oxide, mica, calcium carbonate, etc.) were added to improve the ink absorption of the transparent film or to eliminate the sticking phenomenon between the films, thereby reducing the light transmittance. there was. However, in the present invention, by containing 30% dispersion liquid in which silica of 10 mu m or less is dispersed in water in the ink transmitting layer, the effect of increasing not only ink absorbing power but also light transmittance is obtained. This effect is possible by uniformly distributing the silica particles by dispersing and using the silica in water without directly adding it to the water. The silica dispersion is 30 to 700 parts by weight, preferably 150 to 500 parts by weight based on 100 parts by weight of the binder component constituting the ink permeable layer.

In addition, a small amount of fluorescent dye may be contained in the ink transmitting layer 3b to further improve the apparent light transmittance of the transparent film. Such fluorescent dyes are commonly used, for example, diamino-stilbene- Disulfonic acid derivatives, 4,4'-distyryl biphenyl derivatives, and the like. It is preferable to contain 1-5 weight part of fluorescent dyes with respect to 100 weight part of binder components which comprise an ink permeable layer.

In addition, the sulfate-based compound may be contained in the ink transmitting layer 3b in order to significantly increase the ink absorption power of the transparency. Examples of the sulfate compound include aluminum sulfate, calcium sulfate, magnesium sulfate, and the like, and 0.5 to 2 parts by weight of the sulfate compound is included with respect to 100 parts by weight of the binder component constituting the ink permeable layer.

In addition, the transparency film of the present invention introduced an undercoating layer 2 between the base film 1 and the ink fixing layer 3a to prevent the ink absorbing layer from being detached from the base film. The thickness of the undercoat layer 2 is advantageously coated as thinly as possible within the range in which the effect is exhibited, and is preferably maintained at about 0.5 to 1 μm. The undercoating layer 2 is preferably coated with toluene with 2 to 4% of para chlorophenol coating liquid.

The present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

(Examples 1 to 3)

The polyethylene terephthalate film having a thickness of 100 μm was coated using a bar coater, respectively, in the composition of Table 1 below. After coating, it was sufficiently dried in an oven at 100 to 120 ° C. for 30 seconds to 1 minute to prepare a transparency film.

(Comparative Examples 1 to 5)

A transparent film was prepared in the same manner as in Example 1, except that the ink penetrating layer was removed and the ink fixing layer was designed using the composition shown in Table 2.

(Comparative Examples 6 to 8)

A transparent film was prepared in the same manner as in Example 1, except that the coating amounts of the ink fixing layer and the ink transmitting layer or the compositions of the ink fixing layer and the ink transmitting layer were changed as shown in Table 3 below.

Experimental Example

Physical properties of the transparent film according to Examples 1 to 3 and Comparative Examples 1 to 8 were evaluated in the following manner, and the results are shown in Table 4 below.

Transmittance measurement: Transmittance was measured in the range of 400-700 nm using an ultraviolet spectrometer.

Ink Absorption Measurement: Print a black block image on the film to be measured in an inkjet printer (DESKJET 500C, manufactured by HEWLETT PACKARD) and apply pressure of 18 g / m2 for 3 seconds to investigate the time for the ink to settle on the film. Measured.

Bleeding evaluation: Several primary colors (yellow, magenta, cyan), mixed colors (green, red, blue) and black are adjacent to inkjet printers (DESKJET 500C) and inkjet printers (SIJ-630V, Samsung Electronics, Inc.) manufactured by HEWLETT PACKARD After printing, the bleeding phenomenon (smearing between colors) after 1 hour and 100 hours was evaluated.

Optical Density Evaluation: Print black block using inkjet printer (DESKJET 500C, DESKJET 660K, USA HEWLETT PACKARD) and printer (SIJ-630V, Samsung), and then use a Densitometer According to the light density was measured.

From the results of Table 4, in Examples 1 to 3, it was confirmed that not only the ink absorption but also the light transmittance and no bleeding phenomenon. In Comparative Example 1, when a mixed binder of polyvinyl alcohol and polyvinyl pyrrolidone without an ink transmitting layer is introduced into the ink fixing layer, no problem occurs in light transmittance or bleeding, but the ink absorption is inferior. There are disadvantages. Even if a polyethylene oxide or silica dispersion is added to the mixed binder to improve ink absorption, the ink absorption does not increase significantly due to the absence of the ink permeable layer. (Comparative Examples 2 and 3)

On the other hand, when polyethylene oxide is used as the ink fixing layer binder (Comparative Examples 4, 5, 6, and 8), the ink absorption is excellent, but bleeding occurs. When a small amount of aluminum sulfate is added thereto (Comparative Example 5), compared to using polyethylene oxide in combination with silica dispersion (Comparative Example 4), the ink absorption is improved but the light transmittance is also decreased. . Accordingly, in the present invention, as a result of reducing the disadvantages while utilizing the advantages of polyethylene oxide, aluminum sulfate, and the mixed binder of polyvinyl alcohol and polyvinyl pyrrolidone, a mixed binder of polyvinyl alcohol and polyvinyl pyrrolidone is obtained. In the case where an excess of the ink fixing layer and a small amount of a polyethylene oxide binder were designed in the ink transmitting layer, the physical properties of the optimum transparency film excellent in ink absorption and translucency and no bleeding phenomenon appeared.

In addition, when the polyethylene oxide binder is applied to the ink fixing layer alone (Comparative Examples 4, 5, 6, 8), the light density decreases significantly with time as compared with the initial light density after printing. Not only colors, but also primary colors and other mixed colors. However, in the case of polyvinyl alcohol and polyvinyl pyrrolidone, which are binders of the present invention, the initial light density after printing was maintained over time, so that the color and image persistence were excellent. However, if polyvinyl alcohol and polyvinyl pyrrolidone are applied to the ink fixing layer and there is no ink transmitting layer, there is a disadvantage that the optical density of the pigment type black ink used in the DESKJET 660K printer is greatly reduced (Comparative Example 1 3). This problem is solved by designing polyvinyl alcohol and polyvinyl pyrrolidone in the ink fixing layer, and using it as a polyethylene oxide ink transmission layer having excellent black light density and excellent printing image even in pigment type ink thereon. In Examples 1-3, the hue, image stability, and persistence were also able to be maintained.

Accordingly, in the present invention, an ink fixing layer thickly coated with a polyvinyl alcohol and polyvinyl pyrrolidone mixed binder and a polyethylene oxide or silica dispersion in the same weight ratio. The two-layered ink absorbing layer, which has a thin coating of various additives such as polyethylene oxide binder, silica dispersion liquid, and aluminum sulfate in the ink transmitting layer, has excellent ink absorption, light transmittance, no bleeding phenomenon, and stability over time with color or image. It can be seen that it is suitable for use as a transparent film.

As described above, the inkjet printer transparency film according to the present invention has a general versatility as a coating layer design showing optimal properties simultaneously in various types of printers as compared to a conventional transparency film having optimal properties only in one printer. At the same time, by introducing aluminum sulfate, which is not applied in the prior art, the ink absorbency and light transmittance are excellent, there is no bleeding phenomenon, and color or image stability over time is also effective.

Claims (10)

In a transparent film for an inkjet printer, in which an ink fixing layer 3a and an ink transmitting layer 3b are sequentially stacked as an ink absorbing layer 3 on one side of the base film 1, the ink fixing layer 3a ) Contains the same amount of polyvinyl alcohol and polyvinyl pyrrolidone as binder components, and the ink permeable layer 3b contains polyethylene oxide as a binder component. . 2. The binder component according to claim 1, wherein the binder component contained in the ink fixing layer 3a is 5 to 15% by weight based on the ink layer composition, and the binder component contained in the ink transmitting layer 3b is 5 to 5 based on the ink layer composition. A transparency film for an inkjet printer, characterized in that it contains 15% by weight. The transparency film for an inkjet printer according to claim 1, wherein the ink fixing layer (3a) has a thickness of 10 to 20 µm, and the ink transmitting layer (3b) has a thickness of 0.5 to 5 µm. The transparency film of claim 1, wherein the polyvinyl alcohol is a cation-modified polyvinyl alcohol having a degree of saponification of 86 to 91 mol%. The transparency film for an inkjet printer according to claim 1, wherein the polyvinyl pyrrolidone has a molecular weight of 1,000,000 to 1,500,000. The transparency film of claim 1, wherein the polyethylene oxide binder has a molecular weight of 300, 000 to 500,000. The transparency film of claim 1, wherein the ink fixing layer contains 10 parts by weight or less of polyethylene oxide or 70 parts by weight or less of silica dispersion based on 100 parts by weight of the binder component. 2. The ink permeable layer according to claim 1, wherein the ink permeable layer contains 30 to 700 parts by weight of silica dispersion, 1 to 5 parts by weight of a fluorescent dye, and 0.5 to 2 parts by weight of a compound based on sulfate. Transparency film for inkjet printers. The transparency film of claim 7 or 8, wherein the silica dispersion liquid is dispersed in water at a concentration of 30% or less by 10 µm or less. The transparency film for an inkjet printer according to claim 1, wherein an undercoating layer (2) containing parachlorophenol and toluene is introduced between the base film (1) and the ink fixing layer (3a).