KR20220047410A - Water Soluble Coating Materials For Paper Coating And Manufacturing Method Thereof - Google Patents

Abstract

The present invention relates to an eco-friendly water-soluble paper coating composition and a manufacturing method thereof. More specifically, the eco-friendly water-soluble paper coating composition comprises, with respect to 100 parts by weight of an organic solvent, 10 to 30 parts by weight of a cellulose derivative, 1 to 10 parts by weight of a plasticizer, 3 to 30 parts by weight of a slip agent, and 0.5 to 50 parts by weight of a dispersing agent. According to the present invention, the eco-friendly water-soluble paper coating composition is easily coated on paper, provides excellent water resistance, oil resistance, and heat-sealing properties, and is made of cellulose so that it is harmless to the human body. In addition, a water-soluble coating film coated on paper is formed of a cellulose material like paper and is easily dissociated in water or alkaline solution, thereby facilitating recycling and being biodegradable in the natural environment to be returned to nature.

Description

Eco-friendly Water Soluble Coating Material Manufacturing Method {Water Soluble Coating Materials For Paper Coating And Manufacturing Method Thereof}

The present invention relates to a water-soluble coating composition for paper coating comprising a plasticized cellulose derivative and a method for preparing the same.

In modern social life, active time, moving distance, and information to be acquired are increasing, and at the same time, limited time must be used as efficiently as possible.

Food intake that provides energy is one of human activities that cannot be excluded, and various containers are used because it is necessary to quickly and conveniently consume necessary food in a limited time even in busy modern social life.

In particular, in modern life, the use of disposable products is rapidly increasing due to the development of science and technology, quality improvement in living standards and culture, and the pursuit of convenience. Various disposable containers such as containers and containers for ice cream have been developed and used.

Disposable containers as described above often use paper, and in the case of paper, the inside is coated with a waterproof material to solve the problem of hygroscopicity.

Polyethylene (POLYETHYLENE: PE) is widely used for coating the paper container.

In general, polyethylene is known as a plastic and is a chemical substance widely used in surrounding household products due to its advantages such as light, rust, and non-corrosion, as well as chemical safety, water resistance, flexibility, insulation, and moldability.

The polyethylene is generally used for the purpose of waterproofing by being coated inside various food containers for reasons such as excellent food hygiene and relatively inexpensive distribution, but the coated container using the same releases environmental hormones during use and disposal. can be In addition, the polyethylene-coated container does not dissociate in water in the process of dissociation for recycling after use, so recycling costs increase because it has to go through a screening process.

As a result, pulp is continuously imported for the manufacture of paper containers, and there are limitations in terms of resource recycling and environmental destruction. Because it takes hundreds of years to grow, it is the main culprit of soil pollution. Moreover, the polyethylene coating process is fundamentally required

Due to the dissolution process of polyethylene chips at about 200 °C and volatile organic solvents (VOCs), it causes environmental problems due to high cost and deterioration of the working environment/air pollution.

In addition, the polyethylene coating has a very high risk of exposure to carcinogens and the release of environmental hormones depending on the conditions of use, and since it induces toxicity when exposed to the human body for a long period of time, problems are raised in terms of food hygiene and safety. As a prior art for overcoming this, packaging made of a water-soluble resin made of an acrylic emulsion, a slip agent, and a dispersant.

A resin for use is disclosed. Although this technology is eco-friendly, renewable, and food packaging resin that does not release environmental hormones, it is difficult to coat because of its high viscosity, and because of the high water content, the rate at which water volatilizes during coating is slow and workability is poor. In addition, the acrylic emulsion has a problem in that the paper becomes stiff due to its hard nature and the coating film of the hinge part is damaged, so that water and oil easily permeate into the paper and it takes a lot of time to dissociate into water during recycling.

An object of the present invention is to provide a water-soluble coating composition for paper coating that is environmentally friendly and recyclable by including a plasticized cellulose derivative. Another object of the present invention is to provide a method for preparing a water-soluble coating composition.

In order to achieve the above object, the water-soluble coating composition of the present invention contains 10 to 30 parts by weight of a cellulose derivative, 1 to 10 parts by weight of a plasticizer, and 3 to 30 parts by weight of a slip agent based on 100 parts by weight of the organic solvent.

The water-soluble coating composition further comprises 05 to 50 parts by weight of a dispersant based on 100 parts by weight of the organic solvent.

The organic solvent is methyl benzene, ethyl acetate, methyl acetate, propyl acetate, benzene, chlorobenzene, ethanol, and isopropanol. Isopropanol) is at least one selected from the group consisting of.

The cellulose derivative is at least one selected from the group consisting of methyl cellulose, ethyl cellulose, hydroxypropylmethyl cellulose, cellulose acetate, and nitro cellulose.

The plasticizer is at least one selected from the group consisting of triacetine, triethylcitrate, dicyclohexyl phthalate, ESO (Epoxidized soybean oil) and glycerol.

The slip agent is selected from the group consisting of paraffin wax emulsion, Lico wax emulsion, polyethylene wax emulsion, silicone emulsion, and stearic acid monomer. more than one

The dispersant is at least one selected from the group consisting of hydrophilic silica, acrylic emulsion, diester sulfosuccinate, and urethane emulsion.

In order to achieve the above other object, the method for preparing a water-soluble coating composition of the present invention includes heating an organic solvent to 30 to 60°C; adding 10 to 30 parts by weight of a cellulose derivative based on 100 parts by weight of the heated organic solvent and stirring at 30 to 60° C. for 60 to 200 minutes; adding 1 to 10 parts by weight of a plasticizer to the stirred mixture based on 100 parts by weight of an organic solvent for a plasticization reaction and stirring at 30 to 60° C. for 10 to 80 minutes; adding 3 to 30 parts by weight of a slip agent to the mixture containing the plasticizer based on 100 parts by weight of an organic solvent and stirring; and aging the mixture containing the slip agent at 30 to 80° C. for 2 to 10 hours.

Between the step of adding a slip agent to the mixture containing the plasticizer and stirring the mixture and the step of aging the mixture, the method further includes adding and stirring 05 to 50 parts by weight of a dispersant based on 100 parts by weight of the organic solvent.

The water-soluble coating composition of the present invention is easily coated on paper with a thin coating film due to excellent workability, and excellent water resistance, oil resistance and heat sealing properties are imparted even when the coating film is applied thinly.

In addition, the water-soluble coating composition of the present invention maintains water resistance and oil resistance for 3-4 days in a heat-dried state, but when recycled paper coated with a water-soluble coating composition is stirred in water or alkaline solution, the coating film and the coating film by mechanical stirring treatment The paper dissociates quickly, making it easy to recycle.

In addition, the water-soluble coating composition of the present invention is harmless to the human body because it uses a cellulose derivative of the same material as paper, and the paper coated with the water-soluble coating composition is biodegradable in a natural environment and returns to nature. composition.

1 is a flow chart showing a method for manufacturing the coating composition of the present invention according to an embodiment.

The present invention is easily coated on paper by including 10 to 30 parts by weight of a cellulose derivative, 1 to 10 parts by weight of a plasticizer, and 3 to 30 parts by weight of a slip agent with respect to 100 parts by weight of an organic solvent, and excellent water resistance, oil resistance and heat sealing properties are provided. It relates to a water-soluble coating composition that is harmless to the human body as well as a method for manufacturing the same. In this case, the water-soluble coating composition may further include 05 to 50 parts by weight of a dispersant.

Hereinafter, the present invention will be described in detail.

Since the water-soluble coating composition of the present invention contains a plasticized cellulose derivative, excellent water resistance, oil resistance and heat sealing properties can be imparted even when applied thinly to paper.

Cellulose is generally insoluble in water, but if the hydroxyl group of the glucose ring constituting cellulose is substituted with a methyl group, an ethyl group, or a hydroxyl group, it becomes water-soluble depending on the degree of substitution.

The cellulose derivative of the present invention significantly reduces hydrogen bonding by substituting a hydroxyl group (-OH) of cellulose by nitration, acetylation or etherification, and the hydrophilic hydroxyl group is changed to another hydrophobic group.

Examples of the cellulose derivative include methyl cellulose, ethyl cellulose, hydroxy

and one or two or more selected from the group consisting of propylmethyl cellulose, cellulose acetate, and nitro cellulose.

The cellulose derivative is used in an amount of 10 to 30 parts by weight, preferably 10 to 20 parts by weight, based on 100 parts by weight of the organic solvent. When the content of the cellulose derivative is less than 10 parts by weight, water resistance and oil resistance cannot be imparted to the paper. It does not dry quickly, causing the coating solution to stick to each other.

The plasticizer is to plasticize the cellulose derivative, for example, triacetine, triethylcitrate, dicyclohexyl phthalate, ESO (Epoxidized soybean)

oil) and one or more selected from the group consisting of glycerol (Glycerol).

The plasticizer is used in an amount of 1 to 10 parts by weight, preferably 1 to 6 parts by weight, based on 100 parts by weight of the organic solvent. When the content of the plasticizer is less than 1 part by weight, the cellulose does not become solution and the heat sealing property of the coating film is lowered. is increased, not only carbonization of the paper occurs, but also the crystallinity of the cellulose particles is weakened, making it impossible to form a water-resistant and oil-resistant coating film.

By plasticizing cellulose with a plasticizer, solid cellulose is made into solution and the viscosity of the solution is maintained so that paper, etc. can be easily coated.

The slip agent lowers the coefficient of friction of the paper coated with the coating composition of the present invention, thereby enhancing lubricity and improving surface strength, thereby preventing the interlayer contact/adhesion phenomenon of paper that may occur during the printing operation, which is a post process, and coating By imparting slip properties to the composition, it not only makes the dry film thickness of the coating film thin, but also provides excellent water resistance and oil resistance. Examples of such slip agents include paraffin wax emulsion, Lico wax emulsion, polyethylene wax emulsion, silicone emulsion, and stearic acid monomer. 1 type or 2 or more types selected from the group can be mentioned.

The slip agent is used in an amount of 3 to 30 parts by weight, preferably 3 to 20 parts by weight, based on 100 parts by weight of the organic solvent. If the content of the slip agent is less than 3 parts by weight, the lubricity is lowered and sticking occurs due to the blocking phenomenon between the coating films. When slip-zero waxes are used, the wax absorbs oil and the oil resistance decreases.

The dispersing agent disperses substances such as cellulose derivatives, increases suspendability, and improves storage stability, for example, hydrophilic silica, acrylic emulsion, diester sulfosuccinate, and One or two or more selected from the group consisting of urethane emulsion may be mentioned.

The dispersant is used in an amount of 05 to 50 parts by weight, preferably 2 to 30 parts by weight, based on 100 parts by weight of the organic solvent. When the content of the dispersant is less than 05 parts by weight, a dispersing effect cannot be expected, and when the content is more than 50 parts by weight, the suspendability is excellent, but it is not preferable from an economic point of view.

Examples of the organic solvent include methyl benzene, ethyl acetate, methyl acetate, propyl acetate, benzene, chlorobenzene, ethanol, and ethanol. One or two or more selected from the group consisting of isopropanol may be mentioned.

When forming a coating film with the coating composition of the present invention, the coating amount of the coating film is 5 to 20 g/m 2 , preferably 7 to 15 g/m 2 . If the coating amount of the coating film is less than 5 g/m2, excellent oil resistance, water resistance and heat sealing properties are not obtained. Considering the aspect, it is an undesirable degree.

In addition, the amount of coating can be formed by applying the coating composition at once, but it is preferable to apply it twice in order to obtain more excellent water resistance, oil resistance and heat sealing properties. In particular, when the surface of the paper is rough, it is preferable to apply 2 to 3 g/m 2 first and then apply the second application. Also, the present invention provides a manufacturing method using a water-soluble coating composition, see FIG. 1 . to explain

First, an organic solvent is added to the stirrer and heated to 30 to 60° C. (S110)

A cellulose derivative is added to the organic solvent heated in step S110 and stirred at a speed of 1,000 to 2,000 RPM for 60 to 200 minutes while maintaining 30 to 60 °C (S120) If the stirring time is less than 60 minutes, sufficient mixing is not made. Therefore, it is difficult to plasticize the cellulose later, and when the stirring time is more than 200 minutes, the organic solvent is volatilized and the subsequent process cannot be performed. In addition, when the stirring speed is less than 1,000 RPM, it is difficult to plasticize the cellulose later because sufficient mixing is not made.

A plasticizer is added to the mixture prepared in step S120 to cause the plasticization reaction, and stirred at a speed of 1,000 to 2,000 RPM for 10 to 80 minutes while maintaining 30 to 60 ° C. (S130) When the temperature is less than 30 ° C., cellulose It is not plasticized, and when the temperature is higher than 60 ℃, the organic solvent is volatilized and the continuous process cannot be performed. In order to plasticize the cellulose, the temperature should be maintained in steps S110 to S130.

When the stirring time is less than 10 minutes in step S130, plasticization of the cellulose derivative is not sufficient, and when the stirring time is more than 80 minutes, the viscosity of the mixture increases due to excessive plasticization.

After adding a slip agent to the mixture prepared in step S130 and stirring at a speed of 1,000 to 2,000 RPM for 10 to 80 minutes (S140), it is aged at 30 to 80° C. for 2 to 10 hours (S150) in step S140 If the prepared mixture is not aged under the conditions of step S150, the interpolymer bond is not stabilized, so the solution is separated by release between the solvent and the solute.

Also, between steps S140 and S150, a step (S160) of stirring at a speed of 1,000 to 2,000 RPM for 10 to 80 minutes by adding a dispersing agent to the mixture prepared in step S140 may be added.

The coating composition of the present invention forms a coating film on one side of the paper using a coating device. There is no particular limitation on the coater of the coating device, but 2 to 6 roller bar braid coaters, comma coaters, spray coaters, mesh or mesh coaters, casting coaters, gravure coaters, dropping coaters, air knife coaters, etc. can be used. can

In addition, by coating the water-soluble coating composition on paper (base paper) or the like, it is possible to manufacture paper containers, food packaging paper, and the like. Since the above paper has to meet various demands in the coating process, cutting process, printing process, molding process, etc., it is used that has excellent strength, long-term storage, moisture resistance, dimensional stability, processing aptitude, etc., and there are special restrictions on this However, it is preferable to use bleached chemical pulp as a raw material and to use paper excellent in folding resistance and moldability.

Hereinafter, preferred examples are presented to help the understanding of the present invention, but the following examples are merely illustrative of the present invention, and it will be apparent to those skilled in the art that various changes and modifications are possible within the scope and spirit of the present invention, It goes without saying that such variations and modifications fall within the scope of the appended claims.

Example 1

400 parts by weight of methylbenzene and 600 parts by weight of ethanol were put into a stirrer, and then heated to 40° C. using hot water. Then, 150 parts by weight of nitrocellulose was added under the same temperature and stirred for 80 minutes. At the same temperature as above, 20 parts by weight of dicyclohexyl phthalate was added and stirred for 30 minutes, and then 60 parts by weight of the paraffin wax emulsion was added and stirred for 30 minutes. The mixture thus obtained was aged at 35° C. for 5 hours to prepare a water-soluble coating composition.

The prepared coating composition was first coated on food paper so that the coating amount was 10 g/m 2 , and then dried in a drying oven at 120° C. for 5 minutes.

Example 2

The same procedure as in Example 1, except that the coating composition prepared in Example 1 was first coated on food paper so that the coating amount was 3 g/m2, dried, and secondarily coated so that the coating amount was 7 g/m2, at 120 ° C. It was dried in a drying oven for 3 minutes.

Example 3

400 parts by weight of methylbenzene and 600 parts by weight of ethanol were put into a stirrer, and then heated to 40° C. using hot water. Then, 150 parts by weight of nitrocellulose was added under the same temperature and stirred for 80 minutes. At the same temperature as above, 20 parts by weight of triacetin was added and stirred for 30 minutes, and then 60 parts by weight of Ricoh wax emulsion was added and stirred for 30 minutes. this

Then, 20 parts by weight of hydrophilic silica was added and stirred for 50 minutes. The mixture thus obtained was aged at 35° C. for 5 hours to prepare a water-soluble coating composition.

The prepared coating composition was first coated on food paper so that the coating amount was 12 g/m 2 , and then dried in a drying oven at 120° C. for 5 minutes.

Example 4

The same procedure as in Example 3, except that the coating composition prepared in Example 3 is first coated on food paper so that the coating amount is 5 g/m2, dried, and secondarily coated so that the coating amount is 7 g/m2, at 120 ° C. It was dried in a drying oven for 3 minutes.

Example 5

It was carried out in the same manner as in Example 3, except that methyl cellulose was used instead of nitrocellulose.

Example 6

The same procedure as in Example 5, except that the coating composition prepared in Example 5 is first coated on food paper so that the coating amount is 5 g/m2, dried, and secondarily coated so that the coating amount is 7 g/m2, at 120 ° C. It was dried in a drying oven for 3 minutes.

Comparative Example 1

It was carried out in the same manner as in Example 3, but a plasticizer (triacetin) was not used.

Comparative Example 2

The same procedure as in Comparative Example 1, except that the coating composition prepared in Comparative Example 1 was first coated on food paper so that the coating amount was 3 g/m2, dried, and secondarily coated so that the coating amount was 7g/m2, and dried at 120 ° C. Dry in the oven for 3 minutes.

Comparative Example 3

The same procedure as in Comparative Example 1, except that the coating composition prepared in Comparative Example 1 was first coated on food paper so that the coating amount was 17 g/m2, dried, and secondarily coated so that the coating amount was 5 g/m2, at 120 ° C. It was dried in a drying oven for 3 minutes.

Comparative Example 4

60 parts by weight of acrylic emulsion, 29 parts by weight of ethylene vinyl acetate emulsion, 9 parts by weight of urethane emulsion, 1 part by weight of SO-7920 from Kwangjin Silicone as a slip agent, and OS-75 from CYTEC, a sodium dioctyl sulfosuccinate-based dispersant, 1 A coating solution was prepared by adding parts by weight, putting it in a reaction vessel, and stirring at room temperature for 30 minutes.

The prepared coating composition was first coated on food paper so that the coating amount was 10 g/m 2 , and then dried in a drying oven at 120° C. for 5 minutes.

Comparative Example 5

The same procedure as in Comparative Example 4, except that the coating composition prepared in Comparative Example 4 was first coated on food paper so that the coating amount was 3 g/m2, dried, and secondarily coated so that the coating amount was 7 g/m2, at 120 ° C. It was dried in a drying oven for 3 minutes.

Comparative Example 6

The same procedure as in Comparative Example 4, except that the coating composition prepared in Comparative Example 4 was first coated on food paper so that the coating amount was 17 g/m2, dried, and secondarily coated so that the coating amount was 5 g/m2, at 120 ° C. It was dried in a drying oven for 3 minutes.

Comparative Example 7

It was carried out in the same manner as in Example 1, but the coating amount was formed to be 3 g/m 2 .

test example.

1 Water resistance and oil resistance: 5 g each of water and cooking oil was applied to one side of the food paper coated with the coating composition, left at room temperature for 1 hour, and then the degree of wetness of water and cooking oil on the food paper was visually observed.

◎: Excellent (water and cooking oil do not get wet at all)

○ : Good (Water and cooking oil are wet to less than 5% on food paper)

□ : Normal (6~10% wet with water and cooking oil on food paper)

△: Bad (11-20% of water and cooking oil wet on food paper)

×: Very poor (food paper wet with water and cooking oil more than 20%)

2 Heat sealing property: After setting the sealing strength of the food paper coated with the coating composition to 5 using a heat sealing machine (Sambotech, SK-310), the degree of falling off of the coating layer and the food paper was visually observed.

◎: Excellent (coating layer and food paper do not fall off)

○: Good (coating layer and food paper fall below 1%)

□: Normal (coating layer and food paper fall to 2-5%)

△: defective (coating layer and food paper fall to 6~10%)

×: Very poor (coating layer and food paper fall to more than 10%)

Table 1

As shown in Table 1 above, it was confirmed that the coating compositions of Examples 1 to 6 according to the present invention were excellent in water resistance, oil resistance and heat sealing properties.

On the other hand, Comparative Examples 1 and 3 in which a plasticizer was not used did not have excellent water resistance, oil resistance, and heat sealing properties.

In addition, in the case of the coating compositions of Comparative Examples 4 to 7 using an acrylic emulsion instead of a cellulose derivative, it was confirmed that the water resistance, oil resistance and heat sealing properties were not excellent. In particular, in Comparative Examples 5 and 6, the secondary coating did not work well on the primary coating film, so the peeling phenomenon after heat sealing was severe.

In addition, it was confirmed that Comparative Example 7 was not excellent in water resistance, oil resistance and heat sealing property due to a small amount of coating.

Claims (1)

claim 1
A water-soluble coating composition further comprising 10 to 30 parts by weight of a cellulose derivative, 1 to 10 parts by weight of a plasticizer, 3 to 30 parts by weight of a slip agent, and 05 to 50 parts by weight of a dispersant based on 100 parts by weight of the organic solvent.
claim 2
According to claim 1, wherein the organic solvent is methyl benzene (Methyl benzene), ethyl acetate (Ethyl acetate), methyl acetate (Methyl acetate), propyl acetate (Propyl acetate), benzene (Benzene), chlorobenzene (Chloro Benzene), ethanol (Ethanol) and isopropanol (Isopropanol) at least one water-soluble coating composition selected from the group consisting of.
claim 3
According to claim 1, wherein the cellulose derivative is methyl cellulose (Methyl cellulose), ethyl cellulose (Ethyl cellulose), hydroxypropylmethyl cellulose (Hydroxypropylmethyl cellulose), cellulose acetate (Cellulose acetate) and nitro cellulose (Nitro cellulose) from the group consisting of At least one selected water-soluble coating composition.
claim 4
According to claim 1, wherein the plasticizer is triacetine (Triacetine), triethyl citrate (Triethylcitrate), dicyclohexyl phthalate (Dicyclohexyl phthalate), ESO (Epoxidized soybean oil) and glycerol (Glycerol) selected from the group consisting of One or more water-soluble coating compositions.
claim 5
According to claim 1, wherein the slip agent is a paraffin wax emulsion (Paraffin wax emulsion), Lico wax emulsion (Lico wax emulsion), polyethylene wax emulsion (Polyethylene wax emulsion), silicone emulsion (Silicone emulsion), stearic acid monomer (Stearic acid monomer) ) at least one water-soluble coating composition selected from the group consisting of.
claim 6
The water-soluble coating composition of claim 1, wherein the dispersant is at least one selected from the group consisting of hydrophilic silica, acrylic emulsion, diester sulfosuccinate, and urethane emulsion.
claim 7
heating the organic solvent to 30 to 60° C.; adding 10 to 30 parts by weight of a cellulose derivative based on 100 parts by weight of the heated organic solvent and adding 60 parts by weight at 30 to 60° C.
Stirring for 200 minutes; Adding 1 to 10 parts by weight of a plasticizer based on 100 parts by weight of an organic solvent to the stirred mixture for a plasticization reaction and stirring at 30 to 60° C. for 10 to 80 minutes; The plasticizer adding 3 to 30 parts by weight of a slip agent to a mixture containing 100 parts by weight of an organic solvent and stirring;
A method for preparing a water-soluble coating composition comprising adding 05 to 50 parts by weight of a dispersant based on 100 parts by weight of an organic solvent and stirring the mixture: and aging the mixture containing the slip agent at 30 to 80° C. for 2 to 10 hours .

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