KR20030023397A - A transparent film for laser beam printer - Google Patents

Abstract

PURPOSE: A transparent film for a laser beam printer is provided, which has the good fixedness to a toner of a high speed copier or printer while has the good heat resistance not to produce an embossing owing to a hot fusing. Thereby, the film provides a good color development degree and clear images. CONSTITUTION: The transparent film for a laser beam printer has a toner receiving layer coated on a substrate film. The toner receiving layer has a partial interpenetrating net structure formed by cross-linking an water-soluble polymer represented by the formula 1 to a thermoplastic polymer(wherein, R is hydrogen atom or alkyl of C1-7, 0<=l<1, 0<m, n<1, l+m+n =1). The toner receiving layer comprises 20 to 85 wt.% of the water-soluble polymer, 5 to 70 wt.% of a thermoplastic polymer, 0.1 to 30 wt.% of a cross-linking agent and 5 to 25 wt.% of additives.

Description

Transparent film for laser beam printers {A transparent film for laser beam printer}

The present invention relates to a transparent film for a laser beam printer, and more particularly to a film having a structure in which a toner receiving layer is coated on a base film, wherein the polymer film is a substrate to increase heat resistance upon thermal fusion of the toner to the toner receiving layer. Clear color image, excellent light transmittance and water resistance by using a toner accommodating layer formed by cross-reacting a water-soluble polymer used to improve color reproducibility of the toner between thermoplastic polymers having excellent adhesion and excellent toner fixing ability to form a partially interpenetrating network structure. And a transparent film for a laser beam printer having toner fixing ability and excellent printability.

The printing output method (electrophotography) using a laser beam has been used by consumers in general along with inkjets because of the advantages of high output speed and high resolution images. Electrophotography, which is applied to copiers and printers, usually goes through a five-step imaging process. The first step is to apply a constant charge to the photoconductor drum or belt in the dark, and the second step is to irradiate the laser beam to the photoconductive drum or belt to create an electrostatic latent image. This latent image is then exposed to the charged toner causing the toner to be implanted with an electrostatic force. Fourth, as the recording medium passes between the photoconductive drum or belt and the corona, the toner is transferred to the recording medium. At this time, the recording medium must have a certain degree of conductivity before the image of the toner is transferred by the electrostatic force. The last fifth step is to fix the toner transferred to the recording medium, and is fixed to the toner receiving layer mainly by hot fusing to apply heat and pressure by a roller.

In the laser beam printer using this principle, various recording media such as general paper, specially coated exclusive paper, and special film are used. One of such recording media is a transparent film for a laser beam printer. The transparent film for a laser beam printer is made by coating a material having excellent fixability against toner and excellent heat resistance on a base film such as hydrophobic cellulose acetate or polyester (e.g. polyethylene terephthalate). It is used as a presentation tool in projectors, or in various fields such as exterior wall decoration, design, advertisement, and printing film.

Dedicated transparent films used in general copiers or laser beam printers using toner are mainly uncoated general polyester (PET) films or films in which a toner receiving layer is formed of a binder dissolved in an organic solvent. They have the advantage of being inexpensive, but in the last stage of hot fusing in copiers and laser beam printers, the compatibility and adhesion of the toner are poor, resulting in poor color development of the image area and the concentration of the toner. Due to the flying (flying) of the sharpness has a disadvantage that falls. In order to compensate for this drawback, U.S. Patent No. 4,071,362 uses a thermoplastic polymer to improve fixability between the toner and the film, but this is thermally fused in a printer or copier where the temperature is a little high in the heat fusion step or a slow heat fusion step. Heat is transferred to the surface of the film by the roller, so embossing occurs, and thus a transparent image cannot be obtained. An example of a polymer curing system using a metal compound to prevent embossing due to thermal fusion is disclosed in US Pat. No. 4,415,626. However, since a copying machine or a printer is getting faster, the toner is shorter as the surface of the transparent film is hardened. Is not enough to settle on the film. In addition, in US Patent No. 5,582,902, there was an example of using a color OHP film having a good color mixing efficiency and a good absorption of wax using inorganic pigments of 1-100 nm and polyvinyl alcohol, which is a water-soluble resin. I have a weak problem. The thermoplastic opaque substrate can be a thermoplastic polymer such as polystyrene, polyolefin, acrylic polymer, methacrylic polymer, polyester ionomer, polyamide, polyimide, polyurethane, polyurea, polycarbonate, polyether, polysulfide, etc. An example of making a toner-only sheet having water resistance by coating a dispersed solution is shown in US Pat. No. 5,902,673, but has a disadvantage that it cannot be used because it is opaque and requires transparency.

Accordingly, the present inventors cross-react the water-soluble polymer having excellent reproducibility of color toner between thermoplastic polymer having excellent adhesion to the polymer film as a base material and excellent toner fixing property to solve the above problems. By forming a Semi Inter Penetrating Network), the present invention has completed the present invention having heat resistance and water resistance during thermal fusion.

Therefore, the present invention is a high-speed copier or printer transparent film for a laser beam printer that is excellent in toner fixing property to toner, but also excellent in heat resistance and does not cause embossing by heat fusion, thereby providing excellent color development of the toner and providing a clear image. The purpose is to provide.

1 is a cross-sectional view of a transparent film for a laser beam printer according to the present invention.

<Description of Main Parts of Drawing>

1: back coating layer 2: transparent substrate layer

3: undercoating layer 4: toner receiving layer

The present invention provides a transparent film for a laser beam printer coated with a toner receiving layer on a base film, wherein the toner receiving layer is a laser beam printer in which a partially interpenetrating network structure is formed by crosslinking a water-soluble polymer represented by the following Chemical Formula 1 between thermoplastic polymers. The transparent film for the feature is characterized.

In Chemical Formula 1; R represents a hydrogen atom or an alkyl group having 1 to 7 carbon atoms, 0 ≦ L <1, 0 <m, n <1, and L + m + n = 1.

Referring to the present invention in more detail as follows.

The present invention relates to a film having a structure in which a toner receiving layer is coated on a base film, wherein the toner receiving layer is a thermoplastic polymer having excellent adhesion to toner polymer film having excellent toner fixing properties and a water-soluble polymer used to improve color reproducibility of the toner. To increase heat resistance during thermal fusion of the toner, a water-soluble polymer is cross-linked between the thermoplastic polymers to form a semi-interpenetrating network (SIPN), thereby providing a clear color image and excellent transparency and toner fixing properties. You can finish the film.

The transparent film according to the present invention has a structure in which a toner receiving layer is coated on a base film, and is more sensitive to constituents of an image receiving layer in which a latent image is exposed to a charged toner and the toner is implanted with an electrostatic force. It will be described in detail as follows.

First, in order to provide excellent fixability between the toner and the base film, 5 to 70 wt% of the thermoplastic polymer is contained in the total toner receiving layer composition as a binder having excellent affinity with styrene-acrylate, styrene-butadiene, polyester, etc. It is desirable to. If the content is less than 5% by weight, there is a problem that the toner is fixed to the receiving layer. If the content exceeds 70% by weight, the toner is smeared. The thermoplastic polymer may be a polyester-based, polyvinyl alcohol-based, polyvinyl acetal-based, polyacryl-based, cellulose-based, or polyurethane-based polymers having a molecular weight of 2,000 to 50,000, and is preferably produced when using an organic solvent. In consideration of environmental problems, workability and conductivity, it is preferable to use a sulfonic acid group or a carboxyl group, or a water-dispersed polyester in the form of ammonium salt, a water-dispersed polyurethane, or a water-based acrylic polymer. The thermoplastic polymer preferably has a glass transition temperature (Tg) of 5 to 75 ° C. in order to improve fixability with the toner. If the glass transition temperature is less than 5 ° C., the fixed toner may be smeared. If the temperature exceeds 75 ° C, the toner is hardly fixed.

In order to improve the print clarity of the color toner in the toner receiving layer, it is preferable to contain 20 to 85% by weight of the water-soluble polymer represented by the formula (1) in the total toner receiving layer composition, and if the content is outside the above range, the sharpness of the color toner is There is a problem in reproducing.

The water-soluble polymer has a high enough glass transition temperature even before crosslinking, has heat resistance against heat fusion, and preferably has a molecular weight of 1,000 to 30,000, which is more effective due to crosslinking, and more preferably, an environment produced when using an organic solvent. It is preferable to use polyvinyl alcohol or polyvinyl acetal which is easy to be soluble in consideration of problems, workability and conductivity. The polyvinyl alcohol or polyvinyl acetal has an advantage of providing a transparent film having excellent thermal stability and good compatibility with thermoplastic polymers.

The present invention is characterized in that the crosslinking reaction of the water-soluble polymer between the thermoplastic polymer to form a partially interpenetrating network structure to improve heat resistance to heat to prevent embossing by heat, and to improve the water resistance by crosslinking the water-soluble polymer.

In the present invention, the crosslinking agent used to crosslink the water-soluble polymer between the thermoplastic polymers is preferably contained in an amount of 0.1 to 30% by weight in the total toner receiving layer composition, and if the content is less than 0.1% by weight, the crosslinking reaction is incomplete. If the content exceeds 30% by weight, the crosslinking becomes excessive, resulting in poor fixability of the toner. As the crosslinking agent, oxazoline, isocyanate, epoxide, aziridine, melamine-formaldehyde or dialdehyde may be used.

In addition, it is preferable to contain an additive having electrical conductivity in the total toner accommodating layer composition in an amount of 5 to 25% by weight in order to fix the toner and prevent scattering of the toner in the toner accommodating layer. There is a problem of blowing, and if it exceeds 25% by weight, there is a problem of deterioration of surface and light transmittance in the toner receiving layer. The additives include inorganic compounds such as zinc oxide, titanium oxide, copper iodide and silver iodide, polyhydric alcohols such as glycerin, propylene glycol, ethylene glycol, polyethylene glycol, trimethylene glycol and sorbitol, and quaternary ammonium salt polymers and cationic quaternary A cellulose polymer, a styrene-maleic anhydride copolymer having a sulfonic acid group, or the like may be used alone or in combination. Preferably, the polyhydric alcohol is used in consideration of the compatibility with the thermoplastic polymer and the water-soluble polymer, and light transmittance. It is good. Since the additives impart conductivity to the transparent film, it is possible to prevent the fixing and the scattering of the toner, as well as the antistatic function, which simultaneously solves the problem of continuous feeding caused by static electricity.

On the other hand, in recent years, the toner particles have become smaller in order to improve the resolution of the laser beam printer. As the particles become smaller, the scattering of the images on the toner accommodating layer is more likely to occur due to the coulomb repulsive force, and the moisture contained during the heat fusion vaporizes. The image is buckled or blistered. The present invention can also solve this problem by using the above additive.

In addition, in the present invention, in order to further improve the toner fixing ability of the toner accommodating layer and to impart antiblocking, slippage and surface (surface feeling), the organic and inorganic fillers may be added in an amount of 0.1 to 5 wt% based on 100 wt% of the toner aqueous layer composition. It can also be added. The organic filler may be polyethylene, polypropylene, polystyrene, polyacrylate, modified starch, starch oxide particles, and the like, and as inorganic fillers, calcium carbonate, kaolin, clay, zinc oxide, titanium oxide, barium sulfate, alumina, Silica and the like can be used. Such an organic-inorganic filler is preferably contained in the total toner fixation composition in the range of 5% by weight or less. In addition, it is preferable to use the particle size of the said organic-inorganic filler between 1-60 micrometers.

In the present invention, a fluorescent dye, an antioxidant, an antifoaming agent, and the like may be additionally added to the toner receiving layer in addition to the above components. The fluorescent dye increases the apparent light transmittance felt by the eye, and when used appropriately within the range of 0.01 to 0.5% by weight in the toner receiving layer composition, the light transmittance of the transparent film can be further improved.

As a coating liquid solvent for coating the toner receiving layer composition on the base film, it is preferable to use a mixture of an organic solvent such as alcohol, glycol ether, ketone and water in consideration of dissolution of polymer and drying after coating. Is preferably used within 50% of the total solvent. The alcohol may be methanol, ethanol, isopropanol, methyl cellosolve, etc., and is used within 50% of the total solvent. In order to adjust the concentration of hydrogen ions in the coating solution, a base such as an amine may be added.

A toner receiving layer 4 containing the above components is coated on the transparent substrate 2 as shown in FIG. 1, although the toner fixation tends to increase as the coating amount of the toner receiving layer increases, but a constant coating amount is reached. This will no longer improve the toner fixing degree. Therefore, the coating amount of the toner receiving layer is suitably about 0.1 to 15 g / m ² , and the thickness thereof is preferably about 0.1 to 15 μm.

In addition, in FIG. 1, the undercoating layer 3 may be selectively coated between the base film and the toner receiving layer using paraclophenol having good adhesion to the toner receiving layer and the base film component in order to improve the adhesion of the toner receiving layer to the base film. The coating amount may be in the range of 0.2 to 2 g / m ² , and the preferred coating thickness is suitably within about 1 μm. In addition, in FIG. 1, the rear coating layer 1 may be selectively coated on the back side of the base film to prevent the films from sticking to each other.

As the base film of the present invention, polyester (polyethylene terephthalate), which is widely used in general copiers, is generally used, and its thickness is easy to handle and prevents warping during drying of a film coated with a coating liquid. The degree is appropriate, preferably about 120 μm. Moreover, polycarbonate, cellulose acetate, etc. can also be used as a base film according to the use of the transparent film for laser beam printers.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited by Examples.

Example 1.

Each of the following compositions was coated on a polyethylene terephthalate film having a thickness of 120 μm in order using a bar coater, and then dried in an oven (110 ° C., 1 minute) to give an undercoat of about 0.6 μm and a toner receiving layer of about 5 μm. The transparent film was prepared as much as possible.

A) undercoating layer

Parachlorophenol 3% by weight

Toluene 97% by weight

B) toner receiving layer

Polyester (Korea SK Chemicals, EW370) 40.0 wt%

Polyvinyl butyral (9 mol% acetalized; 8% aqueous solution) 30.0 wt%

5.5 wt% glyoxal (40% aqueous solution)

Glycerin 10.0 wt%

Water 10.0% by weight

Isopropanol 4.5 wt%

Example 2

A transparent film was manufactured in the same manner as in Example 1 except that the composition of the toner accommodating layer was carried out as follows.

Polyurethane (Netherlands Genecaze, R-970; 39% aqueous dispersion) 50.0 wt%

Polyvinyl alcohol (89% saponification) 30.0 weight%

Glyoxal (40% aqueous solution) 5.3% by weight

Glycerin 7.0 wt%

5.0 wt% of water

2.7 wt% ethanol

Example 3

A transparent film was manufactured in the same manner as in Example 1 except that the composition of the toner accommodating layer was carried out as follows.

Styrene-acrylic resins (manufactured by Hanwha Chemical, R-40; 46%) 35.0 wt%

50.0% by weight of polyvinyl butyral (9 mol% acetalized; 8% aqueous solution)

Glyoxal (40% aqueous solution) 2.0 wt%

Glycerin 5.0 wt%

Sorbitol 0.5 wt%

Oxidized Starch (SUN-SIZE, made by Samyang Genex, Korea) 0.1 wt%

3.4% by weight of water

Ethanol 4.0 wt%

Comparative Example 1

A transparent film was manufactured in the same manner as in Example 1 except that the composition of the toner accommodating layer was carried out as follows.

Polyester (Korea SK Chemicals, EW370) 40.0 wt%

5.5 wt% glyoxal (40% aqueous solution)

Glycerin 10.0 wt%

Water 25.0 wt%

19.5% by weight of isopropanol

Comparative Example 2

A transparent film was manufactured in the same manner as in Example 1 except that the composition of the toner accommodating layer was carried out as follows.

Polyurethane (Netherlands Genecaze, R-970; 39% aqueous dispersion) 50.0 wt%

Polyvinyl alcohol (89% saponification) 30.0 weight%

Glycerin 7.0 wt%

10.3% by weight of water

Ethanol 2.7 wt%

Comparative Example 3

A transparent film was manufactured in the same manner as in Example 1 except that the composition of the toner accommodating layer was carried out as follows.

Polyvinyl butyral (9 mol% acetalized; 8% aqueous solution) 85.0 wt%

Glyoxal (40% aqueous solution) 2.0 wt%

Glycerin 5.0 wt%

Sorbitol 0.5 wt%

Oxidized Starch (SUN-SIZE, made by Samyang Genex, Korea) 0.1 wt%

3.4% by weight of water

Ethanol 4.0 wt%

Comparative Example 4

A transparent film was manufactured in the same manner as in Example 1 except that the composition of the toner accommodating layer was carried out as follows.

Polyester (Korea SK Chemicals, EW370) 80% by weight

5% by weight polyvinyl butyral (9 mol% acetalized; 8% aqueous solution)

Glyoxal (40% aqueous solution) 3% by weight

2% by weight glycerin

5 wt% water

5% by weight of isopropanol

Experimental Example

Transmittance and water resistance of the transparent films prepared in Examples 1 to 3 and Comparative Examples 1 to 4 were measured, and the results are shown in Table 1 below.

In addition, after printing a test image using a color laser beam printer (HEWLETT PACKARD) and a black and white laser beam printer (LaserJet 4MV) of the United States HEWLETT PACKARD (light color density, color development), embossing and sharpness ( Scattering) was measured, and the results are shown in Table 2 below.

As shown in Tables 1 and 2, the transparent films of Examples 1 to 3 according to the present invention do not have embossing, so the light transmittance is excellent, and the toner fixing property is excellent, so that both water resistance and sharpness are excellent. there was. However, in Comparative Example 1, in which only the thermoplastic polymer was used, embossing occurred in the heat fusion step, the film surface was clouded, and thus the light transmittance was remarkably decreased. In Comparative Example 2, the water-soluble polymer was simply mixed without crosslinking the water-soluble polymer between the thermoplastic polymers, which showed some resistance to thermal fusion, but showed problems in water resistance. Comparative Example 3, in which only the water-soluble polymer is used, shows excellent results in light transmittance and water resistance. However, since the thermoplastic polymer is excluded, the toner fixability is low during printing, and thus the light density of the color is not high. You can also see the drop in saints. In addition, Comparative Example 4 outside the scope of the present invention was confirmed that the embossing is generated during the fusion of the toner, the light transmittance is bad, and the water resistance and sharpness are also bad.

As described above, the transparent film for a laser beam printer according to the present invention forms a partially interpenetrating network structure (SIPN) by crosslinking a water-soluble polymer between thermoplastic polymers in a toner-receiving layer to produce a clear color image and excellent color. Since it has light transmittance and toner fixing ability, it can be usefully used for overhead projectors and printing films.

Claims (6)

In the transparent film for a laser beam printer coated with a toner receiving layer on a base film, the toner receiving layer is a laser beam, characterized in that a partially interpenetrating network structure is formed by crosslinking a water-soluble polymer represented by Formula 1 between thermoplastic polymers. Transparencies for printers. Formula 1 In Chemical Formula 1; R represents a hydrogen atom or an alkyl group having 1 to 7 carbon atoms, 0 ≦ L <1, 0 <m, n <1, and L + m + n = 1. According to claim 1, wherein the toner receiving layer is characterized in that it comprises 20 to 85% by weight of the water-soluble polymer represented by the formula (1), 5 to 70% by weight thermoplastic polymer, 0.1 to 30% by weight crosslinking agent and 5 to 25% by weight additives Transparent film for laser beam printers. The method of claim 1 or 2, wherein the thermoplastic polymer is selected from polyester, polyvinyl alcohol, acrylic, cellulose, and polyurethane-based polymers and has a molecular weight of 2,000 to 50,000 and a glass transition temperature of 5 to 75 ℃. Transparent film for a laser beam printer, characterized in that. 3. The transparent film of claim 2, wherein the crosslinking agent is selected from oxazoline, isocyanate, epoxide, aziridine, melamine-formaldehyde and dialdehyde. The method of claim 2, wherein the additive is zinc oxide, titanium oxide, copper iodide, silver iodide, glycerin, propylene glycol, ethylene glycol, polyethylene glycol, trimethylene glycol, sorbitol, quaternary ammonium salt polymer, cationic quaternary cellulose polymer and sulfonic acid A transparent film for a laser beam printer, characterized in that one or two or more selected from styrene-maleic anhydride copolymer having a group. The transparent film for a laser beam printer according to claim 2, wherein a filler is further added in an amount of 0.5 to 5% by weight based on 100% by weight of the toner receiving layer.