KR20200070537A - Manufacturing method of coated paper having excellent water resistance - Google Patents

Abstract

The present invention relates to a method of producing a coated paper, comprising the steps of: preparing a silica sol containing silica particles; mixing a binder solution containing one or more binders selected from the group consisting of polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polyethylene (PE), polyvinylidene chloride (PVdC), oriented polypropylene (OPP), and cellulose, with one or more materials selected from the group consisting of vinyltrimethoxysilane (VTMO) and vinyltriethoxysilane (VTEOS), and one or more materials selected from the group consisting of polyacrylic acid (PAA), formic acid (HCOOH), and acetic acid (CH_3COOH); mixing the silica sol and the modified binder solution to form a coating solution; and applying the coating solution onto a raw paper and drying the same. The coated paper produced according to the present invention has halftone dots with small area and roundness, has improved ink absorbability which may lead to improved printability, and has excellent water resistance.

Description

Manufacturing method of coated paper having excellent water resistance

The present invention relates to a method of manufacturing a coated paper, and more particularly, to a method of manufacturing a coated paper having a small dot area and a roundness and improving ink absorption and improving printability and water resistance.

A paper coated with a ceramic pigment and a binder as a main component on the base paper is called a coated paper.

The purpose of the coating is to improve the aesthetic product value such as the whiteness and gloss of the paper and to improve the printability.

The coating layer formed by coating (coating) the coating solution imparts smoothness that the base paper does not have, and forms a void structure, which greatly affects ink receptivity.

In order to obtain a clear image through digital printing, it is necessary to have a coating layer capable of absorbing a large amount of ink on the surface of the printing paper, and the coating layer must be able to express a high color concentration by adsorbing a large amount of ink dye onto the surface well. .

As digital printing is applied in various industries such as food packaging and electronic printing, issues related to securing water-resistant properties of coating layers used in various environments are increasing.

Republic of Korea Patent Publication No. 10-2016-0077506

The problem to be solved by the present invention is to provide a method of manufacturing a coated paper having a small dot area and a roundness, and having improved ink absorption and improved printability and excellent water resistance.

The present invention, the step of preparing a silica sol containing silica particles, PVA (Polyvinyl alcohol), PVP (Polyvinylpyrrolidone), PE (Polyethylene), PVdC (Poly (Vinylidene Chloride), OPP (Oriented Polypropylene) and cellulose (Cellulose) ) In a binder solution containing one or more binders selected from the group consisting of VTMO (Vinyltrimethoxysilane) and VTEOS (Vinyltriethoxysilane) and at least one material selected from the group consisting of PAA (Poly acrylic acid), formic acid (formic acid, HCOOH) and Mixing one or more substances selected from the group consisting of acetic acid (CH ₃ COOH) to form a modified binder solution, and mixing the silica sol and the modified binder solution to form a coating solution and the base paper It provides a method of manufacturing a coated paper comprising the step of applying and drying the coating solution.

The step of preparing the silica sol may include adding a silica source material and a catalyst to a solvent and reacting with stirring to form a silica sol, wherein the silica source material is tetraethylorthosilicate (TEOS). And one or more materials selected from the group consisting of water glass.

It is preferable to add the catalyst so that the catalyst and the silica source material are in a volume ratio of 1:1 to 10:1, and the catalyst may include NH ₄ OH.

The silica particles may have an average particle diameter of 10 to 100 nm, and the silica sol may be a sol containing 10 to 35% by weight of the silica particles.

The silica sol is Glycidoxypropyl methyldimethoxy silane, Glycidoxypropyl trimethoxy silane, Glycidoxypropyl triethoxy silane, methacryloxypropyl Methacryloxypropyl methydimethoxy silane, methacryloxypropyl trimethoxy silane, Methacryloxypropyl triethoxy silane and Acryloxypropyl trimethoxy silan It may include at least one silane coupling agent selected from the group consisting of.

It is preferable that the silane coupling agent forms 1 to 30 parts by weight based on 100 parts by weight of the silica particles contained in the silica sol.

In the step of forming the coating solution, Glycidoxypropyl methyldimethoxy silane, Glycidoxypropyl trimethoxy silane, Glycidoxypropyl triethoxy silane , Methacryloxypropyl methydimethoxy silane, Methacryloxypropyl trimethoxy silane, Methacryloxypropyl triethoxy silane and Acrylicoxypropyl trimethoxysilane One or more silane coupling agents selected from the group consisting of (Acryloxypropyl trimethoxy silan) may be further mixed to form the coating solution.

The silane coupling agent is preferably mixed to form 1 to 30 parts by weight based on 100 parts by weight of the silica particles contained in the silica sol.

In the step of forming the coating solution, lithium carbonate may be further mixed to form the coating solution.

The lithium carbonate is preferably mixed to contain 0.01 to 15% by weight in the coating solution.

It is preferable to mix the silica sol and the modified binder solution so that the silica contained in the silica sol and the binder contained in the binder solution form a weight ratio of 0.5:1 to 2:1 .

In the step of forming the modified binder solution, at least one material selected from the group consisting of VTMO (Vinyltrimethoxysilane) and VTEOS (Vinyltriethoxysilane) is to make 1 to 30 parts by weight based on 100 parts by weight of the binder contained in the binder solution desirable.

In the step of forming the modified binder solution, at least one substance selected from the group consisting of polyacrylic acid (PAA), formic acid (HCOOH) and acetic acid (CH ₃ COOH) is contained in the binder solution It is preferable to make 1 to 30 parts by weight based on 100 parts by weight of the total content of one or more substances selected from the group consisting of the binder and the VTMO (Vinyltrimethoxysilane) and VTEOS (Vinyltriethoxysilane).

In addition, the present invention, the step of preparing a silica sol containing silica particles, PVA (Polyvinyl alcohol), PVP (Polyvinylpyrrolidone), PE (Polyethylene), PVdC (Poly (Vinylidene Chloride), OPP (Oriented Polypropylene) and cellulose Preparing a binder solution containing at least one material selected from the group consisting of (Cellulose), mixing the silica sol, the binder solution and lithium carbonate to form a coating solution, and applying the coating solution to the base paper And provides a method of manufacturing a coated paper comprising the step of drying.

The step of preparing the silica sol may include adding a silica source material and a catalyst to a solvent and reacting with stirring to form a silica sol, wherein the silica source material is tetraethylorthosilicate (TEOS). And one or more materials selected from the group consisting of water glass.

It is preferable to add the catalyst so that the catalyst and the silica source material are in a volume ratio of 1:1 to 10:1, and the catalyst may include NH ₄ OH.

The silica particles may have an average particle diameter of 10 to 100 nm, and the silica sol may be a sol containing 10 to 35% by weight of the silica particles.

The silica sol is Glycidoxypropyl methyldimethoxy silane, Glycidoxypropyl trimethoxy silane, Glycidoxypropyl triethoxy silane, methacryloxypropyl Methacryloxypropyl methydimethoxy silane, methacryloxypropyl trimethoxy silane, Methacryloxypropyl triethoxy silane and Acryloxypropyl trimethoxy silan It may include at least one silane coupling agent selected from the group consisting of.

It is preferable that the silane coupling agent forms 1 to 30 parts by weight based on 100 parts by weight of the silica particles contained in the silica sol.

In the step of forming the coating solution, Glycidoxypropyl methyldimethoxy silane, Glycidoxypropyl trimethoxy silane, Glycidoxypropyl triethoxy silane , Methacryloxypropyl methydimethoxy silane, Methacryloxypropyl trimethoxy silane, Methacryloxypropyl triethoxy silane and Acrylicoxypropyl trimethoxysilane One or more silane coupling agents selected from the group consisting of (Acryloxypropyl trimethoxy silan) may be further mixed to form the coating solution.

The silane coupling agent is preferably mixed to form 1 to 30 parts by weight based on 100 parts by weight of the silica particles contained in the silica sol.

The lithium carbonate is preferably mixed to contain 0.01 to 15% by weight in the coating solution.

According to the present invention, the area and roundness of the halftone dots are small and the ink absorption is improved, so that the printability can be improved and the water resistance is excellent.

1 is a photograph showing a state in which ink is discharged using a drop watcher on a surface of a coated paper manufactured according to Experimental Example 1.
2 is a photograph showing a state in which ink is discharged using a drop watcher on the surface of a coated paper manufactured according to Experimental Example 2.
3 is a photograph showing a state in which ink is discharged using a drop watcher on the surface of a coated paper manufactured according to Experimental Example 3.
4 is a photograph showing a state in which ink is discharged using a drop watcher on the surface of a coated paper manufactured according to Experimental Example 4.
5 is a photograph showing a state in which ink is discharged using a drop watcher on the surface of a coated paper manufactured according to Experimental Example 5.
6 is a view showing an adhesive strength criterion.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the following embodiments are provided to those of ordinary skill in the art to fully understand the present invention, and may be modified in various other forms, and the scope of the present invention is limited to the embodiments described below. It does not work.

In the description or claims of the present invention, when any one component "includes" another component, it is not limited to being interpreted as being composed of the component only, unless specifically stated otherwise, and other components are further added. It should be understood that it can be included.

A method of manufacturing a coated paper according to one preferred embodiment of the present invention comprises the steps of preparing a silica sol containing silica particles, polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polyethylene (PE), poly(Vinylidene Chloride PVDC) ), OPP (Oriented Polypropylene) and cellulose (Cellulose) in the binder solution containing at least one binder selected from the group consisting of VTMO (Vinyltrimethoxysilane) and VTEOS (Vinyltriethoxysilane) and at least one material selected from the group and PAA (Poly acrylic acid), formic acid (formic acid, HCOOH) and acetic acid (Acetic acid, CH ₃ COOH) to form a modified binder solution by mixing at least one material selected from the group consisting of, and the silica sol and the modified binder solution Mixing to form a coating solution and the step of applying the coating solution to the base paper and drying.

The step of preparing the silica sol may include adding a silica source material and a catalyst to a solvent and reacting with stirring to form a silica sol, wherein the silica source material is tetraethylorthosilicate (TEOS). And one or more materials selected from the group consisting of water glass.

It is preferable to add the catalyst so that the catalyst and the silica source material are in a volume ratio of 1:1 to 10:1, and the catalyst may include NH ₄ OH.

The silica particles may have an average particle diameter of 10 to 100 nm, and the silica sol may be a sol containing 10 to 35% by weight of the silica particles.

The silica sol is Glycidoxypropyl methyldimethoxy silane, Glycidoxypropyl trimethoxy silane, Glycidoxypropyl triethoxy silane, methacryloxypropyl Methacryloxypropyl methydimethoxy silane, methacryloxypropyl trimethoxy silane, Methacryloxypropyl triethoxy silane and Acryloxypropyl trimethoxy silan It may include at least one silane coupling agent selected from the group consisting of.

It is preferable that the silane coupling agent forms 1 to 30 parts by weight based on 100 parts by weight of the silica particles contained in the silica sol.

In the step of forming the coating solution, Glycidoxypropyl methyldimethoxy silane, Glycidoxypropyl trimethoxy silane, Glycidoxypropyl triethoxy silane , Methacryloxypropyl methydimethoxy silane, Methacryloxypropyl trimethoxy silane, Methacryloxypropyl triethoxy silane and Acrylicoxypropyl trimethoxysilane One or more silane coupling agents selected from the group consisting of (Acryloxypropyl trimethoxy silan) may be further mixed to form the coating solution.

The silane coupling agent is preferably mixed to form 1 to 30 parts by weight based on 100 parts by weight of the silica particles contained in the silica sol.

In the step of forming the coating solution, lithium carbonate may be further mixed to form the coating solution.

The lithium carbonate is preferably mixed to contain 0.01 to 15% by weight in the coating solution.

It is preferable to mix the silica sol and the modified binder solution so that the silica contained in the silica sol and the binder contained in the binder solution form a weight ratio of 0.5:1 to 2:1.

In the step of forming the modified binder solution, at least one material selected from the group consisting of VTMO (Vinyltrimethoxysilane) and VTEOS (Vinyltriethoxysilane) is to make 1 to 30 parts by weight based on 100 parts by weight of the binder contained in the binder solution desirable.

In the step of forming the modified binder solution, at least one substance selected from the group consisting of polyacrylic acid (PAA), formic acid (HCOOH) and acetic acid (CH ₃ COOH) is contained in the binder solution It is preferable to make 1 to 30 parts by weight based on 100 parts by weight of the total content of one or more substances selected from the group consisting of the binder and the VTMO (Vinyltrimethoxysilane) and VTEOS (Vinyltriethoxysilane).

Method of manufacturing a coated paper according to another preferred embodiment of the present invention, the step of preparing a silica sol containing silica particles, PVA (Polyvinyl alcohol), PVP (Polyvinylpyrrolidone), PE (Polyethylene), PVdC (Poly (Vinylidene Chloride) ), preparing a binder solution containing at least one material selected from the group consisting of Oriented Polypropylene (OPP) and Cellulose, and mixing the silica sol, the binder solution and lithium carbonate to form a coating solution. And applying and drying the coating liquid on the base paper.

The step of preparing the silica sol may include adding a silica source material and a catalyst to a solvent and reacting with stirring to form a silica sol, wherein the silica source material is tetraethylorthosilicate (TEOS). And one or more materials selected from the group consisting of water glass.

It is preferable to add the catalyst so that the catalyst and the silica source material are in a volume ratio of 1:1 to 10:1, and the catalyst may include NH ₄ OH.

The silica particles may have an average particle diameter of 10 to 100 nm, and the silica sol may be a sol containing 10 to 35% by weight of the silica particles.

The silica sol is Glycidoxypropyl methyldimethoxy silane, Glycidoxypropyl trimethoxy silane, Glycidoxypropyl triethoxy silane, methacryloxypropyl Methacryloxypropyl methydimethoxy silane, methacryloxypropyl trimethoxy silane, Methacryloxypropyl triethoxy silane and Acryloxypropyl trimethoxy silan It may include at least one silane coupling agent selected from the group consisting of.

It is preferable that the silane coupling agent forms 1 to 30 parts by weight based on 100 parts by weight of the silica particles contained in the silica sol.

In the step of forming the coating solution, Glycidoxypropyl methyldimethoxy silane, Glycidoxypropyl trimethoxy silane, Glycidoxypropyl triethoxy silane , Methacryloxypropyl methydimethoxy silane, Methacryloxypropyl trimethoxy silane, Methacryloxypropyl triethoxy silane and Acrylicoxypropyl trimethoxysilane One or more silane coupling agents selected from the group consisting of (Acryloxypropyl trimethoxy silan) may be further mixed to form the coating solution.

The silane coupling agent is preferably mixed to form 1 to 30 parts by weight based on 100 parts by weight of the silica particles contained in the silica sol.

The lithium carbonate is preferably mixed to contain 0.01 to 15% by weight in the coating solution.

Hereinafter, a method of manufacturing a coated paper according to a preferred embodiment of the present invention will be described in more detail.

The high printability of the coating layer is affected by the fine pore structure and hydrophilic properties.

In order to secure a fine pore structure and hydrophilicity, nano-silica particles and a hydrophilic binder are used. Silica (SiO ₂ ) is added in the form of a water-based silica sol.

However, a phenomenon that the coating layer is deformed and removed when the coating layer is in contact with water at a temperature of 50° C. or higher is observed, and thus it is necessary to develop a composition for improving water resistance.

The water resistance of the coating layer is important to control the hydrophobicity of the fine pores by the binder modification and nano-silica particles responsible for bonding the substrate and the coating layer.

<Example 1>

A silica sol containing silica particles is prepared.

The silica sol is a sol in which silica particles are dispersed in a solvent such as water. It is preferable that the silica sol contains 10 to 35% by weight of silica particles, more preferably 15 to 20% by weight. When the content of the silica particles contained in the silica sol is less than 10% by weight, drying for forming the coating layer takes a long time, and a sufficient amount of silica particles is not contained in the coating layer, so that printability may deteriorate. When the content of the silica particles contained in the sol exceeds 35% by weight, dispersibility and stability of the sol may not be good due to aggregation of the silica particles, and accordingly, printability may be deteriorated. The silica sol is one having an average particle diameter of 10 to 100 nm, more preferably about 10 to 60 nm, considering the printability, physical properties, etc. of the coating layer, and the dispersibility, stability, and physical properties of the sol. desirable. When the particle size of the silica particles is less than 10 nm, production of a silica sol may be difficult, and when it exceeds 100 nm, dispersibility, stability, etc. of the sol may not be good, and a coating layer is formed using the silica sol. In the case of discharging ink to the coating layer, the area of the halftone dots may be large, roundness may be large, and ink absorbency may be poor, so that printability may not be good.

The silica sol can be prepared by the following method.

As a starting material for preparing a silica sol, a silica source material, a solvent, and a catalyst are prepared.

The silica source material may be tetraethylorthosilicate (TEOS), water glass, mixtures thereof, and the like.

The solvent may be water (H ₂ O), alcohols such as ethanol, and mixtures thereof.

The catalyst may be a basic material such as NH ₄ OH.

To the solvent, a silica source material and a catalyst are added and reacted with stirring to form a silica sol. It is preferable to perform the stirring at about 10 to 500 rpm. Preferably, the catalyst and the silica source material are in a volume ratio of about 1:1 to 10:1.

When the synthesized silica sol is heated and maintained at a temperature higher than room temperature, for example, 50 to 80°C, growth of silica particles contained in the silica sol occurs.

The silica sol may be directly prepared by the above-described method, or a commercially available one may be used.

Silica particles contained in the silica sol may be surface-modified by adding and stirring a silane coupling agent to the silica sol. The silane coupling agent is Glycidoxypropyl methyldimethoxy silane, Glycidoxypropyl trimethoxy silane, Glycidoxypropyl triethoxy silane, methacryloxy Methacryloxypropyl methydimethoxy silane, methacryloxypropyl trimethoxy silane, Methacryloxypropyl triethoxy silane and Acryloxypropyl trimethoxy silan ) May include one or more substances selected from the group consisting of. It is preferable that the silane coupling agent forms 1 to 30 parts by weight based on 100 parts by weight of the silica particles contained in the silica sol.

In the surface modification process, the silica sol reacts with a silane coupling agent to cause a hydrolysis reaction, and the silica particles contained in the silica sol are surface modified with a silane component. The silane coupling agent undergoes a coupling reaction with Si-OH on the silica surface to cause a hydrolysis reaction to be coated on the surface of the silica particles, and the silica particles are surface modified. When surface-modified by a silane coupling agent, the core is made of silica particles, and the shell surrounding the core has a structure composed of a silane coupling agent. Since the shell surrounding the core is mostly composed of a silane component, the phenomenon of agglomeration of silica particles with each other due to mutual repulsion between the silane components is suppressed, so that dispersibility and stability can be improved. Dispersibility, stability, and the like of the silica sol may be improved by the surface modification, and when the ink is discharged to the coating layer by forming a coating layer using the silica sol, the area of the dot is reduced and roundness ( Roundness) may be reduced, and ink absorption may be improved to improve printability.

VTMO in a binder solution containing at least one binder selected from the group consisting of polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polyethylene (PE), poly(Vinylidene chloride) (PVDC), oriented polypropylene (OPP) and cellulose (cellulose) (Vinyltrimethoxysilane) and one or more substances selected from the group consisting of VTEOS (Vinyltriethoxysilane) and one or more substances selected from the group consisting of PAA (Poly acrylic acid), formic acid (HCOOH) and acetic acid (Acetic acid, CH ₃ COOH) The materials are mixed to form a modified binder solution, which is a solution in which the binder is dissolved in a solvent such as water (H ₂ O).

It is preferable that at least one material selected from the group consisting of VTMO (Vinyltrimethoxysilane) and VTEOS (Vinyltriethoxysilane) is 1 to 30 parts by weight based on 100 parts by weight of the binder contained in the binder solution. At least one material selected from the group consisting of VTMO (Vinyltrimethoxysilane) and VTEOS (Vinyltriethoxysilane) is added to improve the water resistance of the binder.

The PAA (Poly acrylic acid), formic acid (formic acid, HCOOH) and acetic acid (Acetic acid, CH ₃ COOH) at least one material selected from the group consisting of a binder contained in the binder solution and the VTMO (Vinyltrimethoxysilane) and VTEOS It is preferable to make 1 to 30 parts by weight based on 100 parts by weight of the total content of one or more substances selected from the group consisting of (Vinyltriethoxysilane). The PAA (Poly acrylic acid), formic acid (formic acid, HCOOH) and acetic acid (Acetic acid, CH ₃ COOH) selected from the group consisting of one or more substances are added to maximize the water resistance improvement through a crosslinking reaction.

The coating solution is formed by mixing the silica sol and the modified binder solution. It is preferable to mix the silica sol and the modified binder solution so that the silica contained in the silica sol and the binder contained in the binder solution form a weight ratio of 0.5:1 to 2:1.

When forming the coating solution, lithium carbonate may be further mixed to form the coating solution. The lithium carbonate is preferably mixed to contain 0.01 to 15% by weight in the coating solution.

When forming the coating solution, the dispersing agent may be further mixed to form the coating solution. The dispersant is at least one material selected from the group consisting of ammonium polymethacrylate, ammonium polyacrylate, sodium polyacrylic acid and sodium hexameta phosphate. It can contain. Preferably, the dispersant is contained in the coating solution in an amount of 0.1 to 4% by weight, more preferably 0.5 to 3% by weight.

When forming the coating solution, the thickening agent may be further mixed to form the coating solution. The thickener may include at least one material selected from the group consisting of carboxymethyl cellulose (CMC; Carboxymethyl cellulose), hydroxypropylmethyl cellulose, methylcellulose, and sodium alginate. It is preferable that the thickener is contained in the coating solution in an amount of 0.01 to 3% by weight, more preferably 0.2 to 2% by weight.

The coating solution is applied to the base paper and dried. It is needless to say that the coating solution may be coated on one side of the base paper or coated on both sides. The base paper coated with the coating solution may be dried using a hot air dryer or the like. The drying is preferably performed at a temperature of about 80 to 150°C, more preferably about 100 to 120°C. The drying is preferably carried out for 10 seconds to 30 minutes, more preferably 20 seconds to 5 minutes.

The coated paper and the dried base paper may be calendered using a supercalender or the like. The calendering is preferably carried out at a pressure of 200 to 400 psi, more preferably 250 to 350 psi, at a temperature of 55 to 85°C, preferably 65 to 75°C.

<Example 2>

A silica sol containing silica particles is prepared.

The silica sol is a sol in which silica particles are dispersed in a solvent such as water. It is preferable that the silica sol contains 10 to 35% by weight of silica particles, more preferably 15 to 20% by weight. When the content of the silica particles contained in the silica sol is less than 10% by weight, drying for forming the coating layer takes a long time, and a sufficient amount of silica particles is not contained in the coating layer, so that printability may deteriorate. When the content of the silica particles contained in the sol exceeds 35% by weight, dispersibility and stability of the sol may not be good due to aggregation of the silica particles, and accordingly, printability may be deteriorated. The silica sol is one having an average particle diameter of 10 to 100 nm, more preferably about 10 to 60 nm, considering the printability, physical properties, etc. of the coating layer, and the dispersibility, stability, and physical properties of the sol. desirable. When the particle size of the silica particles is less than 10 nm, production of a silica sol may be difficult, and when it exceeds 100 nm, dispersibility, stability, etc. of the sol may not be good, and a coating layer is formed using the silica sol. In the case of discharging ink to the coating layer, the area of the halftone dots may be large, roundness may be large, and ink absorbency may be poor, so that printability may not be good.

The silica sol can be prepared by the following method.

As a starting material for preparing a silica sol, a silica source material, a solvent, and a catalyst are prepared.

The silica source material may be tetraethylorthosilicate (TEOS), water glass, mixtures thereof, and the like.

The solvent may be water (H ₂ O), alcohols such as ethanol, and mixtures thereof.

The catalyst may be a basic material such as NH ₄ OH.

To the solvent, a silica source material and a catalyst are added and reacted with stirring to form a silica sol. It is preferable to perform the stirring at about 10 to 500 rpm. Preferably, the catalyst and the silica source material are in a volume ratio of about 1:1 to 10:1.

When the synthesized silica sol is heated and maintained at a temperature higher than room temperature, for example, 50 to 80°C, growth of silica particles contained in the silica sol occurs.

The silica sol may be directly prepared by the above-described method, or a commercially available one may be used.

VTMO in a binder solution containing at least one binder selected from the group consisting of polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polyethylene (PE), poly(Vinylidene chloride) (PVDC), oriented polypropylene (OPP) and cellulose (cellulose) (Vinyltrimethoxysilane) and one or more substances selected from the group consisting of VTEOS (Vinyltriethoxysilane) and one or more substances selected from the group consisting of PAA (Poly acrylic acid), formic acid (HCOOH) and acetic acid (Acetic acid, CH ₃ COOH) The materials are mixed to form a modified binder solution, which is a solution in which the binder is dissolved in a solvent such as water (H ₂ O).

It is preferable that at least one material selected from the group consisting of VTMO (Vinyltrimethoxysilane) and VTEOS (Vinyltriethoxysilane) is 1 to 30 parts by weight based on 100 parts by weight of the binder contained in the binder solution. At least one material selected from the group consisting of VTMO (Vinyltrimethoxysilane) and VTEOS (Vinyltriethoxysilane) is added to improve the water resistance of the binder.

The PAA (Poly acrylic acid), formic acid (formic acid, HCOOH) and acetic acid (Acetic acid, CH ₃ COOH) at least one material selected from the group consisting of a binder contained in the binder solution and the VTMO (Vinyltrimethoxysilane) and VTEOS It is preferable to make 1 to 30 parts by weight based on 100 parts by weight of the total content of one or more substances selected from the group consisting of (Vinyltriethoxysilane). The PAA (Poly acrylic acid), formic acid (formic acid, HCOOH) and acetic acid (Acetic acid, CH ₃ COOH) selected from the group consisting of one or more substances are added to maximize the water resistance improvement through a crosslinking reaction.

The coating solution is formed by mixing the silica sol and the modified binder solution. It is preferable to mix the silica sol and the modified binder solution so that the silica contained in the silica sol and the binder contained in the binder solution form a weight ratio of 0.5:1 to 2:1.

When forming the coating solution, the silica particles contained in the silica sol may be further modified by further mixing a silane coupling agent. The silane coupling agent is Glycidoxypropyl methyldimethoxy silane, Glycidoxypropyl trimethoxy silane, Glycidoxypropyl triethoxy silane, methacryloxy Methacryloxypropyl methydimethoxy silane, methacryloxypropyl trimethoxy silane, Methacryloxypropyl triethoxy silane and Acryloxypropyl trimethoxy silan ) May include one or more substances selected from the group consisting of. The silane coupling agent is preferably mixed to form 1 to 30 parts by weight based on 100 parts by weight of the silica particles contained in the silica sol.

In the surface modification process, the silica sol reacts with a silane coupling agent to cause a hydrolysis reaction, and the silica particles contained in the silica sol are surface modified with a silane component. The silane coupling agent undergoes a coupling reaction with Si-OH on the silica surface to cause a hydrolysis reaction to be coated on the surface of the silica particles, and the silica particles are surface modified. When surface-modified by a silane coupling agent, the core is made of silica particles, and the shell surrounding the core has a structure composed of a silane coupling agent. Since the shell surrounding the core is mostly composed of a silane component, the phenomenon of agglomeration of silica particles with each other due to mutual repulsion between the silane components is suppressed, so that dispersibility and stability can be improved.

When forming the coating solution, lithium carbonate may be further mixed to form the coating solution. The lithium carbonate is preferably mixed to contain 0.01 to 15% by weight in the coating solution.

When forming the coating solution, the dispersing agent may be further mixed to form the coating solution. The dispersant is at least one material selected from the group consisting of ammonium polymethacrylate, ammonium polyacrylate, sodium polyacrylic acid and sodium hexameta phosphate. It can contain. Preferably, the dispersant is contained in the coating solution in an amount of 0.1 to 4% by weight, more preferably 0.5 to 3% by weight.

When forming the coating solution, the thickening agent may be further mixed to form the coating solution. The thickener may include at least one material selected from the group consisting of carboxymethyl cellulose (CMC; Carboxymethyl cellulose), hydroxypropylmethyl cellulose, methylcellulose, and sodium alginate. It is preferable that the thickener is contained in the coating solution in an amount of 0.01 to 3% by weight, more preferably 0.2 to 2% by weight.

The coating solution is applied to the base paper and dried. It is needless to say that the coating solution may be coated on one side of the base paper or coated on both sides. The base paper coated with the coating solution may be dried using a hot air dryer or the like. The drying is preferably performed at a temperature of about 80 to 150°C, more preferably about 100 to 120°C. The drying is preferably carried out for 10 seconds to 30 minutes, more preferably 20 seconds to 5 minutes.

The coated paper and the dried base paper may be calendered using a supercalender or the like. The calendering is preferably carried out at a pressure of 200 to 400 psi, more preferably 250 to 350 psi, at a temperature of 55 to 85°C, preferably 65 to 75°C.

<Example 3>

A silica sol containing silica particles is prepared.

The silica sol is a sol in which silica particles are dispersed in a solvent such as water. It is preferable that the silica sol contains 10 to 35% by weight of silica particles, more preferably 15 to 20% by weight. When the content of the silica particles contained in the silica sol is less than 10% by weight, drying for forming the coating layer takes a long time, and a sufficient amount of silica particles is not contained in the coating layer, so that printability may deteriorate. When the content of the silica particles contained in the sol exceeds 35% by weight, dispersibility and stability of the sol may not be good due to aggregation of the silica particles, and accordingly, printability may be deteriorated. The silica sol is one having an average particle diameter of 10 to 100 nm, more preferably about 10 to 60 nm, considering the printability, physical properties, etc. of the coating layer, and the dispersibility, stability, and physical properties of the sol. desirable. When the particle size of the silica particles is less than 10 nm, production of a silica sol may be difficult, and when it exceeds 100 nm, dispersibility, stability, etc. of the sol may not be good, and a coating layer is formed using the silica sol. In the case of discharging ink to the coating layer, the area of the halftone dots may be large, roundness may be large, and ink absorbency may be poor, so that printability may not be good.

The silica sol can be prepared by the following method.

As a starting material for preparing a silica sol, a silica source material, a solvent, and a catalyst are prepared.

The silica source material may be tetraethylorthosilicate (TEOS), water glass, mixtures thereof, and the like.

The solvent may be water (H ₂ O), alcohols such as ethanol, and mixtures thereof.

The catalyst may be a basic material such as NH ₄ OH.

To the solvent, a silica source material and a catalyst are added and reacted with stirring to form a silica sol. It is preferable to perform the stirring at about 10 to 500 rpm. Preferably, the catalyst and the silica source material are in a volume ratio of about 1:1 to 10:1.

When the synthesized silica sol is heated and maintained at a temperature higher than room temperature, for example, 50 to 80°C, growth of silica particles contained in the silica sol occurs.

The silica sol may be directly prepared by the above-described method, or a commercially available one may be used.

Silica particles contained in the silica sol may be surface-modified by adding and stirring a silane coupling agent to the silica sol. The silane coupling agent is glycidoxypropyl methyldimethoxy silane, glycidoxypropyl trimethoxy silane, glycidoxypropyl triethoxy silane, methacryloxy Methacryloxypropyl methydimethoxy silane, methacryloxypropyl trimethoxy silane, Methacryloxypropyl triethoxy silane and Acryloxypropyl trimethoxy silan ) May include one or more substances selected from the group consisting of. It is preferable that the silane coupling agent forms 1 to 30 parts by weight based on 100 parts by weight of the silica particles contained in the silica sol.

In the surface modification process, the silica sol reacts with a silane coupling agent to cause a hydrolysis reaction, and the silica particles contained in the silica sol are surface-modified with a silane component. The silane coupling agent undergoes a coupling reaction with Si-OH on the silica surface to cause a hydrolysis reaction to be coated on the surface of the silica particles, and the silica particles are surface modified. When surface-modified by a silane coupling agent, the core is made of silica particles, and the shell surrounding the core has a structure composed of a silane coupling agent. Since the shell surrounding the core is mostly composed of a silane component, the phenomenon of agglomeration of silica particles with each other due to mutual repulsion between the silane components is suppressed, so that dispersibility and stability can be improved. Dispersibility, stability, and the like of the silica sol may be improved by the surface modification, and when the ink is discharged to the coating layer by forming a coating layer using the silica sol, the area of the dot is reduced and roundness ( Roundness) may be reduced, and ink absorption may be improved to improve printability.

Prepare a binder solution containing at least one binder selected from the group consisting of polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polyethylene (PE), poly(Vinylidene chloride) (PVDC), oriented polypropylene (OPP), and cellulose (cellulose) The binder solution is a solution in which the binder is dissolved in a solvent such as water (H ₂ O).

The silica sol, the binder solution and lithium carbonate are mixed to form a coating solution. It is preferable to mix the silica sol and the binder solution so that the silica contained in the silica sol and the binder contained in the binder solution form a weight ratio of 0.5:1 to 2:1. The lithium carbonate is preferably mixed to contain 0.01 to 15% by weight in the coating solution.

When forming the coating solution, the dispersing agent may be further mixed to form the coating solution. The dispersant is at least one material selected from the group consisting of ammonium polymethacrylate, ammonium polyacrylate, sodium polyacrylic acid and sodium hexameta phosphate. It can contain. Preferably, the dispersant is contained in the coating solution in an amount of 0.1 to 4% by weight, more preferably 0.5 to 3% by weight.

When forming the coating solution, the thickening agent may be further mixed to form the coating solution. The thickener may include at least one material selected from the group consisting of carboxymethyl cellulose (CMC; Carboxymethyl cellulose), hydroxypropylmethyl cellulose, methylcellulose, and sodium alginate. It is preferable that the thickener is contained in the coating solution in an amount of 0.01 to 3% by weight, more preferably 0.2 to 2% by weight.

The coating solution is applied to the base paper and dried. It is needless to say that the coating solution may be coated on one side of the base paper or coated on both sides. The base paper coated with the coating solution may be dried using a hot air dryer or the like. The drying is preferably performed at a temperature of about 80 to 150°C, more preferably about 100 to 120°C. The drying is preferably carried out for 10 seconds to 30 minutes, more preferably 20 seconds to 5 minutes.

The coated paper and the dried base paper may be calendered using a supercalender or the like. The calendering is preferably carried out at a pressure of 200 to 400 psi, more preferably 250 to 350 psi, at a temperature of 55 to 85°C, preferably 65 to 75°C.

<Example 4>

A silica sol containing silica particles is prepared.

The silica sol is a sol in which silica particles are dispersed in a solvent such as water. It is preferable that the silica sol contains 10 to 35% by weight of silica particles, more preferably 15 to 20% by weight. When the content of the silica particles contained in the silica sol is less than 10% by weight, drying for forming the coating layer takes a long time, and a sufficient amount of silica particles is not contained in the coating layer, so that printability may deteriorate. When the content of the silica particles contained in the sol exceeds 35% by weight, dispersibility and stability of the sol may not be good due to aggregation of the silica particles, and accordingly, printability may be deteriorated. The silica sol is one having an average particle diameter of 10 to 100 nm, more preferably about 10 to 60 nm, considering the printability, physical properties, etc. of the coating layer, and the dispersibility, stability, and physical properties of the sol. desirable. When the particle size of the silica particles is less than 10 nm, production of a silica sol may be difficult, and when it exceeds 100 nm, dispersibility, stability, etc. of the sol may not be good, and a coating layer is formed using the silica sol. In the case of discharging ink to the coating layer, the area of the halftone dots may be large, roundness may be large, and ink absorbency may be poor, so that printability may not be good.

The silica sol can be prepared by the following method.

As a starting material for preparing a silica sol, a silica source material, a solvent, and a catalyst are prepared.

The silica source material may be tetraethylorthosilicate (TEOS), water glass, mixtures thereof, and the like.

The solvent may be water (H ₂ O), alcohols such as ethanol, and mixtures thereof.

The catalyst may be a basic material such as NH ₄ OH.

To the solvent, a silica source material and a catalyst are added and reacted with stirring to form a silica sol. It is preferable to perform the stirring at about 10 to 500 rpm. Preferably, the catalyst and the silica source material are in a volume ratio of about 1:1 to 10:1.

When the synthesized silica sol is heated and maintained at a temperature higher than room temperature, for example, 50 to 80°C, growth of silica particles contained in the silica sol occurs.

The silica sol may be directly prepared by the above-described method, or a commercially available one may be used.

Prepare a binder solution containing at least one binder selected from the group consisting of polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polyethylene (PE), poly(Vinylidene chloride) (PVDC), oriented polypropylene (OPP), and cellulose (cellulose) The binder solution is a solution in which the binder is dissolved in a solvent such as water (H ₂ O).

The silica sol, the binder solution and lithium carbonate are mixed to form a coating solution. It is preferable to mix the silica sol and the binder solution so that the silica contained in the silica sol and the binder contained in the binder solution form a weight ratio of 0.5:1 to 2:1. The lithium carbonate is preferably mixed to contain 0.01 to 15% by weight in the coating solution.

When forming the coating solution, the silica particles contained in the silica sol may be further modified by further mixing a silane coupling agent. The silane coupling agent is glycidoxypropyl methyldimethoxy silane, glycidoxypropyl trimethoxy silane, glycidoxypropyl triethoxy silane, methacryloxy Methacryloxypropyl methydimethoxy silane, methacryloxypropyl trimethoxy silane, Methacryloxypropyl triethoxy silane and Acryloxypropyl trimethoxy silan ) May include one or more substances selected from the group consisting of. The silane coupling agent is preferably mixed to form 1 to 30 parts by weight based on 100 parts by weight of the silica particles contained in the silica sol.

In the surface modification process, the silica sol reacts with a silane coupling agent to cause a hydrolysis reaction, and the silica particles contained in the silica sol are surface modified with a silane component. The silane coupling agent undergoes a coupling reaction with Si-OH on the silica surface to cause a hydrolysis reaction to be coated on the surface of the silica particles, and the silica particles are surface modified. When surface-modified by a silane coupling agent, the core is made of silica particles, and the shell surrounding the core has a structure composed of a silane coupling agent. Since the shell surrounding the core is mostly composed of a silane component, the phenomenon of agglomeration of silica particles with each other due to mutual repulsion between the silane components is suppressed, so that dispersibility and stability can be improved.

When forming the coating solution, the dispersing agent may be further mixed to form the coating solution. The dispersant is at least one material selected from the group consisting of ammonium polymethacrylate, ammonium polyacrylate, sodium polyacrylic acid and sodium hexameta phosphate. It can contain. Preferably, the dispersant is contained in the coating solution in an amount of 0.1 to 4% by weight, more preferably 0.5 to 3% by weight.

When forming the coating solution, the thickening agent may be further mixed to form the coating solution. The thickener may include at least one material selected from the group consisting of carboxymethyl cellulose (CMC; Carboxymethyl cellulose), hydroxypropylmethyl cellulose, methylcellulose, and sodium alginate. It is preferable that the thickener is contained in the coating solution in an amount of 0.01 to 3% by weight, more preferably 0.2 to 2% by weight.

The coating solution is applied to the base paper and dried. It is needless to say that the coating solution may be coated on one side of the base paper or coated on both sides. The base paper coated with the coating solution may be dried using a hot air dryer or the like. The drying is preferably performed at a temperature of about 80 to 150°C, more preferably about 100 to 120°C. The drying is preferably carried out for 10 seconds to 30 minutes, more preferably 20 seconds to 5 minutes.

The coated paper and the dried base paper may be calendered using a supercalender or the like. The calendering is preferably carried out at a pressure of 200 to 400 psi, more preferably 250 to 350 psi, at a temperature of 55 to 85°C, preferably 65 to 75°C.

Hereinafter, experimental examples according to the present invention are specifically presented, and the present invention is not limited to the experimental examples presented below.

<Experimental Example 1>

A silica sol containing silica particles was prepared. Tetraethylorthosilicate (TEOS), ethanol, NH ₄ OH and distilled water were prepared as starting materials for the preparation of the silica sol. After adding 405 ml of ethanol to 4.2 ml of distilled water and stirring for 2 hours at room temperature, 4.05 ml of TEOS was added and stirred for 30 minutes, and 22.5 ml of NH ₄ OH was added as a catalyst and stirred for 3 hours to sol the silica. (Silica sol) was formed.

A PVA solution was prepared by dissolving polyvinyl alcohol (PVA) having a molecular weight of 10000 in distilled water at 95°C. The PVA solution was made to contain 20% by weight of PVA.

The silica sol and the PVA solution were mixed, stirred at 40°C for 90 minutes, and maintained at room temperature (room temperature) for 24 hours to prepare a coating solution. The silica sol and the PVA solution were mixed so that the content of the silica contained in the silica sol and the PVA contained in the PVA solution formed a weight ratio of 1:1.

Using a bar coater, the coating solution prepared according to Experimental Example 1 was applied to PET on one side, dried at room temperature (room temperature) for 10 minutes, and then dried in an oven at 100° C. for 10 seconds to prepare a coated paper.

<Experimental Example 2>

A silica sol containing silica particles was prepared. Tetraethylorthosilicate (TEOS), ethanol, NH ₄ OH and distilled water were prepared as starting materials for the preparation of the silica sol.

After adding 405 ml of ethanol to 4.2 ml of distilled water and stirring for 2 hours at room temperature, 4.05 ml of TEOS was added and stirred for 30 minutes, and 22.5 ml of NH ₄ OH was added as a catalyst and stirred for 3 hours to sol the silica. (Silica sol) was formed.

A PVA solution was prepared by dissolving polyvinyl alcohol (PVA) having a molecular weight of 10000 in distilled water at 95°C. The PVA solution was made to contain 20% by weight of PVA.

The silica sol and the PVA solution were mixed and stirred at 40°C for 90 minutes, followed by addition of MPTMS (Methacryloxypropyl trimethoxy silane), followed by stirring for 60 minutes, and maintained at room temperature (room temperature) for 24 hours to prepare a coating solution. . The silica sol and the PVA solution were mixed so that the content of the silica contained in the silica sol and the PVA contained in the PVA solution formed a weight ratio of 1:1. The MPTMS was mixed to form 4 parts by weight based on 100 parts by weight of the silica particles contained in the silica sol.

Using a bar coater, the coating solution prepared according to Experimental Example 2 was applied to PET on one side, dried at room temperature (room temperature) for 10 minutes, and then dried in an oven at 100° C. for 10 seconds to prepare coated paper.

<Experimental Example 3>

A silica sol containing silica particles was prepared. Tetraethylorthosilicate (TEOS), ethanol, NH ₄ OH and distilled water were prepared as starting materials for the preparation of the silica sol.

After adding 405 ml of ethanol to 4.2 ml of distilled water and stirring for 2 hours at room temperature, 4.05 ml of TEOS was added and stirred for 30 minutes, and 22.5 ml of NH ₄ OH was added as a catalyst and stirred for 3 hours to sol the silica. (Silica sol) was formed.

A polyvinyl alcohol (PVA) having a molecular weight of 10000 was dissolved in distilled water at 95°C to prepare a PVA solution, and VTMO (vinyltrimethoxysilane) was added thereto, stirred, and cooled to room temperature to form a PVA-VTMO solution. The PVA solution was made to contain 15.5% by weight of PVA. The VTMO was added to 20 parts by weight based on 100 parts by weight of the PVA. A modified PVA solution was prepared by dissolving 10 g of PAA (Poly acrylic acid) in 90 g of PVA-VTMO solution in 900 g of distilled water at 85° C. for 2 hours, and maintaining it at room temperature (room temperature) for 24 hours.

The silica sol and the modified PVA solution were mixed and stirred at 40°C for 90 minutes, followed by addition of MPTMS (Methacryloxypropyl trimethoxy silane), followed by stirring for 60 minutes, and maintained at room temperature (room temperature) for 24 hours to prepare a coating solution. Did. The silica sol and the modified PVA solution were mixed so that the content of silica contained in the silica sol and the PVA contained in the modified PVA solution formed a weight ratio of 1:1. The MPTMS was mixed to form 4 parts by weight based on 100 parts by weight of the silica particles contained in the silica sol.

Using a bar coater, a coating solution prepared according to Experimental Example 3 was applied to PET on one side, dried at room temperature (room temperature) for 10 minutes, and then dried in an oven at 100° C. for 10 seconds to prepare a coated paper.

<Experimental Example 4>

A silica sol containing silica particles was prepared. Tetraethylorthosilicate (TEOS), ethanol, NH ₄ OH and distilled water were prepared as starting materials for the preparation of the silica sol.

After adding 405 ml of ethanol to 4.2 ml of distilled water and stirring for 2 hours at room temperature, 4.05 ml of TEOS was added and stirred for 30 minutes, and 22.5 ml of NH ₄ OH was added as a catalyst and stirred for 3 hours to sol the silica. (Silica sol) was formed.

The silica sol and the PVA solution were mixed and stirred at 40°C for 90 minutes, followed by addition of MPTMS (Methacryloxypropyl trimethoxy silane), stirring for 60 minutes, maintaining at room temperature (room temperature) for 24 hours, and lithium carbonate. It was added and stirred for 90 minutes, and maintained at room temperature (room temperature) for 24 hours to prepare a coating solution. The silica sol and the PVA solution were mixed so that the content of the silica contained in the silica sol and the PVA contained in the PVA solution formed a weight ratio of 1:1. The MPTMS was mixed to form 4 parts by weight based on 100 parts by weight of the silica particles contained in the silica sol. The lithium carbonate was made to contain 5% by weight in the coating solution.

Using a bar coater, the coating solution prepared according to Experimental Example 4 was applied to PET on one side, dried at room temperature (room temperature) for 10 minutes, and then dried in an oven at 100° C. for 10 seconds to prepare a coated paper.

<Experimental Example 5>

A silica sol containing silica particles was prepared. Tetraethylorthosilicate (TEOS), ethanol, NH ₄ OH and distilled water were prepared as starting materials for the preparation of the silica sol.

After adding 405 ml of ethanol to 4.2 ml of distilled water and stirring for 2 hours at room temperature, 4.05 ml of TEOS was added and stirred for 30 minutes, and 22.5 ml of NH ₄ OH was added as a catalyst and stirred for 3 hours to sol the silica. (Silica sol) was formed.

A polyvinyl alcohol (PVA) having a molecular weight of 10000 was dissolved in distilled water at 95°C to prepare a PVA solution, and VTMO (vinyltrimethoxysilane) was added thereto, stirred, and cooled to room temperature to form a PVA-VTMO solution. The PVA solution was made to contain 20% by weight of PVA. The VTMO was added to 20 parts by weight based on 100 parts by weight of the PVA. A modified PVA solution was prepared by dissolving 10 g of polyacrylic acid (PAA) in 90 g of PVA-VTMO solution in 900 g of distilled water at 85° C. for 2 hours, and maintaining at room temperature (room temperature) for 24 hours.

The silica sol and the modified PVA solution were mixed and stirred at 40° C. for 90 minutes, followed by addition of MPTMS (Methacryloxypropyl trimethoxy silane), stirring for 60 minutes, maintaining at room temperature (room temperature) for 24 hours, and lithium carbonate Was added and stirred for 90 minutes, and maintained at room temperature (room temperature) for 24 hours to prepare a coating solution. The silica sol and the modified PVA solution were mixed so that the content of silica contained in the silica sol and the PVA contained in the modified PVA solution formed a weight ratio of 1:1. The MPTMS was mixed to form 4 parts by weight based on 100 parts by weight of the silica particles contained in the silica sol. The lithium carbonate was made to contain 5% by weight in the coating solution.

Using a bar coater, the coating solution prepared according to Experimental Example 5 was applied to PET one-sided, dried at room temperature (room temperature) for 10 minutes, and then dried in an oven at 100° C. for 10 seconds to prepare a coated paper.

To evaluate the coated paper, ink was discharged using a drop watcher on the finished coated paper surface, and the dot area and roundness of the dots were calculated based on the images observed with an optical microscope. .

Roundness was calculated by the following equation.

[Mathematics]

In the above equation,'r' means the radius of the long axis of the dot, and'A' means the area of the dot.

The ink is discharged using a drop watcher on the surface of the coated paper manufactured according to Experimental Examples 1 to 5, and the area of the dots is measured and the roundness is shown in Table 1 below. Did.

Experimental Example 1 Experimental Example 2 Experimental Example 3 Experimental Example 4 Experimental Example 5 Roundness 1.45 1.43 1.26 1.14 1.07 Dot Area(㎛ ² ) 7921 7744 6889 6724 6561

1 is a photograph showing a state in which ink is discharged using a drop watcher on a surface of a coated paper prepared according to Experimental Example 1, and FIG. 2 is a drop watcher using a drop watcher on a coated surface prepared according to Experimental Example 2 3 is a photograph showing a state in which ink is discharged, and FIG. 3 is a photograph showing a state in which ink is discharged using a drop watcher on a coated paper surface prepared according to Experimental Example 3, and FIG. 4 is a coated paper surface prepared according to Experimental Example 4 A photograph showing a state in which ink is ejected using a drop watcher, and FIG. 5 is a photograph showing a state in which ink is ejected using a drop watcher on a surface of a coated paper manufactured according to Experimental Example 5.

Referring to Table 1, FIGS. 1 to 5, it was found that the area of the halftone dots was small and the roundness was small in the order of Experimental Example 1, Experimental Example 2, Experimental Example 3, Experimental Example 4, and Experimental Example 5. The small dot area and the small roundness mean that the ink absorbency is improved, so that the printability is excellent.

The water resistance of the coating layer was evaluated using the adhesive strength of the coating layer, and the change in the adhesive strength was measured after immersing a film of a certain standard (2×2 cm) in water at 45° C. for 48 hours. 6 shows the adhesive strength criteria.

Referring to FIG. 6, when the edges of the cuts are completely flat, and the squares of the lattice are not detached, the adhesive strength is indicated as '0'.

Table 2 below shows the results of the evaluation of the adhesive strength.

division Adhesive strength
(BEFORE) Adhesive strength
(AFTER) Experimental Example 1 0 2 Experimental Example 2 0 2 Experimental Example 3 0 0 Experimental Example 4 0 0 Experimental Example 5 0 0

Referring to Table 2, in the case of Experimental Example 1 and Experimental Example 2, it is determined that there is a problem in water resistance. In the case of Experimental Examples 3 to 5, it was found that the water resistance of the coated paper was excellent.

As described above, the preferred embodiment of the present invention has been described in detail, but the present invention is not limited to the above embodiment, and various modifications can be made by those skilled in the art.

Claims (15)

Preparing a silica sol containing silica particles;
VTMO in a binder solution containing at least one binder selected from the group consisting of polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polyethylene (PE), poly(Vinylidene chloride) (PVDC), oriented polypropylene (OPP) and cellulose (cellulose) (Vinyltrimethoxysilane) and one or more substances selected from the group consisting of VTEOS (Vinyltriethoxysilane) and one or more substances selected from the group consisting of PAA (Poly acrylic acid), formic acid (HCOOH) and acetic acid (CH ₃ COOH) Mixing the materials to form a modified binder solution;
Forming a coating solution by mixing the silica sol and the modified binder solution; And
Method of manufacturing a coated paper comprising the step of applying and drying the coating solution on the base paper.
Preparing a silica sol containing silica particles;
Prepare a binder solution containing one or more substances selected from the group consisting of polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polyethylene (PE), poly(Vinylidene chloride) (PVDC), oriented polypropylene (OPP), and cellulose (cellulose) To do;
Forming a coating solution by mixing the silica sol, the binder solution, and lithium carbonate; And
Method of manufacturing a coated paper comprising the step of applying and drying the coating solution on the base paper.
According to claim 1 or claim 2, The step of preparing the silica sol,
And adding a silica source material and a catalyst to the solvent and reacting with stirring to form a silica sol.
The silica source material is tetraethyl orthosilicate (TEOS; Tetraethylorthosilicate) and a method of manufacturing a coated paper comprising at least one material selected from the group consisting of water glass.
The method of claim 3, wherein the catalyst and the silica source material is added to the catalyst to achieve a volume ratio of 1:1 to 10:1,
The catalyst is NH ₄ OH manufacturing method of coated paper, characterized in that it comprises.
The method according to claim 1 or 2, wherein the silica particles have an average particle diameter of 10 to 100 nm,
The silica sol is a method of manufacturing a coated paper, characterized in that the sol containing 10 to 35% by weight of the silica particles.
The method according to claim 1 or 2, wherein the silica sol is glycidoxypropyl methyldimethoxy silane, glycidoxypropyl trimethoxy silane, glycidoxypropyl triethoxy silane. (Glycidoxypropyl triethoxy silane), Methacryloxypropyl methydimethoxy silane, Methacryloxypropyl trimethoxy silane, Methacryloxypropyl triethoxy silane and Acryloxy Method for producing a coated paper comprising at least one silane coupling agent selected from the group consisting of propyl trimethoxysilane (Acryloxypropyl trimethoxy silan).
7. The method of claim 6, wherein the silane coupling agent comprises 1 to 30 parts by weight based on 100 parts by weight of the silica particles contained in the silica sol.
According to claim 1 or claim 2, In the step of forming the coating solution,
Glycidoxypropyl methyldimethoxy silane, Glycidoxypropyl trimethoxy silane, Glycidoxypropyl triethoxy silane, methacryloxypropyl methyldimethoxy silane (Methacryloxypropyl methydimethoxy silane), methacryloxypropyl trimethoxy silane, methacryloxypropyl triethoxy silane and acryloxypropyl trimethoxy silan. Method for producing a coated paper, characterized in that to form the coating solution by further mixing one or more selected silane coupling agents.
The method of claim 8, wherein the silane coupling agent is mixed to form 1 to 30 parts by weight based on 100 parts by weight of the silica particles contained in the silica sol.
The method of claim 1, wherein in the step of forming the coating solution, lithium carbonate is further mixed to form the coating solution.
The method of claim 10, wherein the lithium carbonate is mixed to contain 0.01 to 15% by weight in the coating solution.
The method of claim 2, wherein the lithium carbonate is mixed to contain 0.01 to 15% by weight in the coating solution.
The coated paper of claim 1, wherein the silica sol and the modified binder solution are mixed so that the silica contained in the silica sol and the binder contained in the binder solution form a weight ratio of 0.5:1 to 2:1. Manufacturing method.
According to claim 1, In the step of forming the modified binder solution,
The method of manufacturing coated paper, characterized in that at least one material selected from the group consisting of VTMO (Vinyltrimethoxysilane) and VTEOS (Vinyltriethoxysilane) forms 1 to 30 parts by weight with respect to 100 parts by weight of the binder contained in the binder solution.
According to claim 1, In the step of forming the modified binder solution,
The PAA (Poly acrylic acid), formic acid (formic acid, HCOOH) and acetic acid (Acetic acid, CH ₃ COOH) at least one material selected from the group consisting of a binder contained in the binder solution and the VTMO (Vinyltrimethoxysilane) and VTEOS (Vinyltriethoxysilane) method of manufacturing a coated paper, characterized in that to achieve 1 to 30 parts by weight based on 100 parts by weight of the total content of one or more materials selected from the group consisting of.

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