KR101039637B1 - Water soluble coating materials for paper coating and manufacturing method thereof - Google Patents

Abstract

PURPOSE: A solution coating composition for paper coating and a method for manufacturing the same are provided to ensure excellent workability, waterproof, oil resistance, and heat sealing property. CONSTITUTION: A method for manufacturing a soluble coating composition for paper coating comprise: a step of heating an organic solvent at 30-60°C(S110); a step of adding 10-30 weight parts of cellulose derivative to 100 weight parts of heated organic solvent and stirring at 30-60°C for 60-200 minutes(S120); a step of 1-10 weight parts of plasticizer based on 100 weight parts of organic solvent and stirring at 30-60°C for 10-80 minutes(S130); a step of adding 3-30 weight parts of slip agent to the mixture(S140); a step of adding 0.5-50 weight parts of dispersing agent based on 100 weight parts of organic solvents; and a step of maturing the mixture containing the slip agent at 30-80°C for 2-10 hours(S150).

Description

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 producing the same.

Modern social life should use the limited time as efficiently as possible while increasing the activity time, distance, and information to be learned.

One of the activities that can not be excluded is the intake of foods that provide energy, and various containers are used because it is necessary to quickly and easily ingest the necessary foods in a limited time even in busy modern social life.

In particular, modern life is rapidly increasing the use of disposable products due to the development of advanced science and technology, quality of life and culture, and the pursuit of convenience, while the cups of vending machines, beverage packaging containers, cup noodles containers, and takeout containers for beverages. Various disposable containers such as containers and ice cream containers have been developed and used.

Disposable containers as described above are often used paper, the case of paper is coated with a waterproof material in order to solve the problem of hygroscopicity.

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

Polyethylene is generally known as plastic and is a chemical that is widely used in peripheral household goods due to its advantages such as lightness, rust and corrosion, as well as chemical safety, water resistance, flexibility, insulation, and moldability.

The polyethylene is generally used for the purpose of waterproofing and coating the inside of various food containers for reasons such as excellent food hygiene and distribution price is relatively low, but the coating container using this releases environmental hormones during use and disposal. Can be. In addition, the polyethylene coated container is not dissociated with water in the dissociation process for recycling after use, and thus the recycling cost is increased.

As a result, pulp is continuously imported in the manufacture of paper containers, and there are limitations in terms of recycling resources and environmental destruction.In addition, smoke generated during incineration causes air pollution, and natural decomposition occurs even when landfilling. It takes hundreds of years to become a major contributor to soil pollution. In addition, the polyethylene coating process causes environmental problems due to high cost and lowering of working environment / air pollution due to the dissolution process of polyethylene chips of about 200 ° C. and volatile organic solvents (VOCs).

In addition, polyethylene coating has a high risk of exposure to environmental hormones and carcinogens depending on the conditions of use, and poses problems in terms of food hygiene and safety because it causes toxicity to humans for a long time.

The prior art for overcoming this is a packaging resin consisting of a water-soluble resin, a slip agent and a dispersant made of an acrylic emulsion. This technology is not only eco-friendly and renewable, but also a food packaging resin that does not release environmental hormones, but due to its high viscosity, the coating is difficult and the water content is high. In addition, the acrylic emulsion has a problem that the paper is stiff due to the hard characteristics, the coating film of the hinge portion is damaged, water and oil easily penetrate the paper, and dissociates into water during recycling.

The present invention aims to provide an environmentally friendly, water-soluble coating composition for recyclable paper coatings by including plasticized cellulose derivatives.

It is another object of the present invention to provide a method for producing a water-soluble coating composition.

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

The water-soluble coating composition further comprises 0.5 to 50 parts by weight of the dispersant based on 100 parts by weight of the organic solvent.

The organic solvent is methyl benzene, ethyl acetate, ethyl acetate, methyl acetate, propyl acetate, benzene, benzene, chlorobenzene, ethanol and isopropanol. (Isopropanol) is one or more 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 one or more selected from the group consisting of triacetin, triethylcitrate, dicyclohexyl phthalate, EsO, Epoxidized soybean oil, and glycerol.

The slip agent in the group consisting of paraffin wax emulsion (Paraffin wax emulsion), ricowax emulsion (Lico wax emulsion), polyethylene wax emulsion (Silicone emulsion), stearic acid monomer (Stearic acid monomer) It is one or more selected.

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

Method for producing a water-soluble coating composition of the present invention in order to achieve the above another object is to warm the organic solvent to 30 to 60 ℃; Adding 10 to 30 parts by weight of the 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 100 parts by weight of the organic solvent to the stirred mixture 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 100 parts by weight of the organic solvent and stirring the mixture containing the plasticizer; And aging the mixture containing the slip agent at 30 to 80 ° C. for 2 to 10 hours.

The method further includes adding 0.5 to 50 parts by weight of the dispersant with respect to 100 parts by weight of the organic solvent between the step of adding and stirring the slip agent to the mixture including the plasticizer and the step of aging the mixture.

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

In addition, the water-soluble coating composition of the present invention maintains the water resistance and oil resistance for 3 to 4 days in the heat treatment dry state, but when the paper coated with the water-soluble coating composition is stirred in water or alkaline solution when recycled, the coating film and Paper dissociates quickly and can be easily recycled.

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 the paper, the paper coated with the water-soluble coating composition is biodegradable in the natural environment to return to nature, composted and eco-friendly Composition.

1 is a flowchart illustrating a method of preparing a coating composition of the present invention according to one embodiment.

The present invention comprises 10 to 30 parts by weight of cellulose derivative, 1 to 10 parts by weight of plasticizer and 3 to 30 parts by weight of slip agent based on 100 parts by weight of the organic solvent, and is easily coated on paper to provide excellent water resistance, oil resistance and heat sealing resistance. In addition, the present invention relates to a water-soluble coating composition which is harmless to the human body and a method for preparing the same. In this case, the water-soluble coating composition may further include 0.5 to 50 parts by weight of the dispersant.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The water-soluble coating composition of the present invention may be imparted with excellent water resistance, oil resistance and heat sealing even if it is thinly coated on paper by including a plasticized cellulose derivative.

Cellulose is generally insoluble in water, but if the hydroxyl group of the glucose ring constituting the cellulose is replaced with a methyl group, an ethyl group, or a hydroxy group, the cellulose becomes water-soluble according to the degree of substitution.

In the cellulose derivative of the present invention, the hydroxy group (-OH) of cellulose is replaced by nitration, acetylation or etherification to significantly reduce the hydrogen bond, and the hydrophilic hydroxyl group is changed to another hydrophobic group.

Examples of cellulose derivatives include one selected from the group consisting of methyl cellulose, ethyl cellulose, hydroxypropylmethyl cellulose, cellulose acetate, and nitro cellulose. 2 or more types are mentioned.

The cellulose derivative is used in 10 to 30 parts by weight, preferably 10 to 20 parts by weight with respect to 100 parts by weight of the organic solvent. If the content of the cellulose derivative is less than 10 parts by weight, it is impossible to impart water resistance and oil resistance to the paper. If the content is more than 30 parts by weight, the coating may have a poor viscosity due to agglomeration during coating due to the high viscosity of the coating solution. It does not dry quickly, causing a cracking phenomenon in which the coating liquids stick together.

The plasticizer is used to plasticize cellulose derivatives, such as triacetine, triethylcitrate, dicyclohexyl phthalate, EsO (epoxidized soybean oil) and glycerol (Glycerol). 1 type, or 2 or more types selected from the group which consists of these are mentioned.

The plasticizer is used in 1 to 10 parts by weight, preferably 1 to 6 parts by weight, based on 100 parts by weight of the organic solvent. If the content of the plasticizer is less than 1 part by weight, the cellulose is not liquefied and the heat sealing property of the coating film is lowered. If the content is more than 3 parts by weight, the cellulose particles are decomposed to increase the processing temperature. Not only increases the carbonization of the paper, but also weakens the crystallinity of the cellulose particles, thereby making it impossible to form a water- and oil-resistant coating film.

By plasticizing cellulose with a plasticizer, a solution of solid cellulose is maintained and the viscosity of the solution is maintained so that paper or the like is easily coated.

The slip agent lowers the friction coefficient of the paper coated with the coating composition of the present invention to induce lubrication enhancement and surface strength, thereby preventing interlayer adhesion / adhesion of paper, which may occur during post-process printing, and coating Slip property is imparted to the composition to allow the dry film thickness of the coating film to be formed thin, as well as to impart excellent water resistance and oil resistance. Examples of such slip agents include a paraffin wax emulsion, a licowax emulsion, a polyethylene wax emulsion, a silicone emulsion, and a stearic acid monomer. 1 type, or 2 or more types selected from the group can be mentioned.

The slip agent is used in 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 to each other due to the breaking phenomenon between the coating film occurs. If the content is more than 30 parts by weight, it is difficult to coat the paper, etc. If wax is used as a slip agent, the wax absorbs oil and oil resistance is lowered.

The dispersant disperses materials such as cellulose derivatives, increases susceptibility, and improves storage stability. Examples of the dispersant include hydrophilic silica, acrylic emulsion, diester sulfosuccinate, and One or two or more selected from the group consisting of urethane emulsions.

The dispersant is used in an amount of 0.5 to 50 parts by weight, preferably 2 to 30 parts by weight, based on 100 parts by weight of the organic solvent. If the content of the dispersant is less than 0.5 parts by weight can not be expected dispersing effect, if the content is more than 50 parts by weight suspension is excellent, but it is not preferable in terms of economics.

 Examples of the organic solvent include methyl benzene, ethyl acetate, ethyl acetate, methyl acetate, propyl acetate, benzene, benzene, chlorobenzene and ethanol. And isopropanol (Isopropanol) is selected from the group consisting of one or two or more.

When the coating film is formed of 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 / ㎡ it does not obtain excellent oil resistance, water resistance and heat sealing, and if the coating amount is more than 20 g / ㎡, it is more economical, but it is more economical Considered in terms of aspect, it is undesirable.

In addition, the coating amount may be formed by applying the coating composition at once, but in order to obtain more excellent water resistance, oil resistance and heat sealing, it is preferable to apply the coating twice. In particular, in the case where the surface of the paper is rough, it is preferable to apply 2 to 3 g / m 2 first and then apply the second coating.

In addition, the present invention provides a manufacturing method using a water-soluble coating composition, it will be described with reference to FIG.

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

In step S110, the cellulose derivative is added to the heated organic solvent 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, it is difficult to plasticize the cellulose later, since sufficient mixing is not made, and if the stirring time is more than 200 minutes, the organic solvent is volatilized and the subsequent process cannot proceed. In addition, when the stirring speed is less than 1,000 RPM, it is difficult to plasticize the cellulose later, since sufficient mixing is not made, and when the stirring speed is more than 2,000 RPM, bubbles are generated and the solution cannot overflow to continue the process.

The plasticizer is added to the mixture prepared in step S120 to cause the plasticization reaction and stirred at a rate of 1,000 to 2,000 RPM for 10 to 80 minutes while maintaining 30 to 60 ° C. (S130). If the temperature is less than 30 ℃ cellulose is not plasticized, if the temperature is over 60 ℃ organic solvent is volatilized to continue the process. In order to plasticize cellulose, the temperature must be maintained in steps S110 to S130.

If the stirring time is less than 10 minutes in step S130, the plasticization of the cellulose derivative is not sufficient, if the stirring time is more than 80 minutes, the viscosity of the mixture rises due to excessive plasticization.

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

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

The coating composition of the present invention forms a coating film on one side of the paper by using a coating device. The coater of the coating apparatus is not particularly limited, but a two to six-stage roller barb coater, a comma coater, a spray coater, a mesh or dot coater, a casting coater, a gravure coater, a dropping coater, or an air knife coater may be used. Can be.

In addition, the water-soluble coating composition is coated on paper (base paper) or the like to produce a paper container, food packaging paper and the like. Since the paper has to meet various requirements in the process of coating, cutting, printing, molding, etc., it has excellent strength, long-term storage, moisture resistance, dimensional stability, processability, etc. However, a paper having bleaching chemical pulp as a raw material and excellent in cutting resistance and moldability is preferable.

Hereinafter, preferred examples are provided to aid the understanding of the present invention, but the following examples are merely for exemplifying the present invention, and it will be apparent to those skilled in the art that various changes and modifications can be made within the scope and spirit of the present invention. It is natural 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 added to a stirrer, heated to 40 ° C. using hot water, and 150 parts by weight of nitrocellulose were added under the same temperature, followed by stirring for 80 minutes. Under the same temperature as above, 20 parts by weight of dicyclohexylphthalate was added and stirred for 30 minutes, and then 60 parts by weight of 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 coating composition prepared above was first coated on food paper so that the coating amount was 10 g / m 2, and dried in a 120 ° C. drying oven for 5 minutes.

Example 2.

The same process 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 / ㎡, dried and then coated so that the second coating amount is 7 g / ㎡ 120 ℃ 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 added to a stirrer, heated to 40 ° C. using hot water, and 150 parts by weight of nitrocellulose were added under the same temperature, followed by stirring for 80 minutes. Under 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 rico wax emulsion was added and stirred for 30 minutes. 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 coating composition prepared above was first coated on food paper so that the coating amount was 12 g / m 2, and dried in a 120 ° C. drying oven for 5 minutes.

Example 4.

The same process as in Example 3, except that the coating composition prepared in Example 3 was coated on food paper so that the first coating amount is 5 g / ㎡ and dried to coat the second coating amount to 7 g / ㎡ 120 ℃ It was dried in a drying oven for 3 minutes.

Example 5.

The same procedure as in Example 3, except that methyl cellulose was used instead of nitrocellulose.

Example 6.

The same process as in Example 5, except that the coating composition prepared in Example 5 was coated on food paper so that the first coating amount is 5 g / ㎡ and dried to coat the second coating amount to 7 g / ㎡ 120 ℃ It was dried in a drying oven for 3 minutes.

Comparative Example 1.

It carried out similarly to Example 3, but did not use a plasticizer (triacetin).

Comparative Example 2

The coating composition prepared in Comparative Example 1 was carried out in the same manner as in Comparative Example 1, but the coating composition was first coated on food paper so that the coating amount was 3 g / m 2, and then the coating composition was dried so that the coating amount was 7g / m 2 and dried at 120 ° C. Dry in oven for 3 minutes.

Comparative Example 3

The coating composition prepared in Comparative Example 1 was carried out in the same manner as in Comparative Example 1, but the coating composition was first coated on food paper so that the coating amount was 17 g / m 2 and dried, and then the coating composition was coated so that the coating amount was 5 g / m 2. 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 of CYTEC Co., Ltd., a sodium dioctyl sulfosuccinate dispersant. The coating solution was prepared by adding the parts by weight and putting the reaction vessel into the reaction vessel for 30 minutes at room temperature.

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

Comparative Example 5.

The coating composition prepared in Comparative Example 4 was carried out in the same manner as in Comparative Example 4, the coating composition was first coated on food paper so that the coating amount was 3 g / m 2, and then dried and the coating composition was coated so that the coating amount was 7 g / m 2. It was dried in a drying oven for 3 minutes.

Comparative Example 6.

The coating composition prepared in Comparative Example 4 was carried out in the same manner as in Comparative Example 4, the coating composition was first coated on food paper so that the coating amount was 17 g / m 2 and dried, and the coating composition was secondly coated so that the coating amount was 5 g / m 2. It was dried in a drying oven for 3 minutes.

Comparative Example 7.

It carried out similarly to Example 1, but formed so that coating amount might be 3 g / m <2>.

Test example.

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

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

○: Good (water and cooking oil less than 5% wet in food paper)

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

(Triangle | delta): Poor (11-20% wetness of water and cooking oil in food paper)

×: Very poor (water and cooking oil soaked in food paper exceeding 20%)

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

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

○: Good (coating layer and food sheet fell below 1%)

□: Normal (coating layer and food sheet dropped to 2 ~ 5%)

(Triangle | delta): Poor (coating layer and food paper fall to 6-10%)

×: Very poor (coating layer and food sheet dropped to more than 10%)

division Water resistance Oil resistance Heat sealing Example 1 ◎ ◎ ◎ Example 2 ◎ ◎ ◎ Example 3 ◎ ◎ ◎ Example 4 ◎ ◎ ◎ Example 5 ◎ ◎ ◎ Example 6 ◎ ◎ ◎ Comparative Example 1 × × × Comparative Example 2 × × × Comparative Example 3 × × × Comparative Example 4 ○ □ □ Comparative Example 5 □ □ △ Comparative Example 6 □ △ △ Comparative Example 7 × × △

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

On the other hand, Comparative Examples 1 and 3 without using a plasticizer did not have excellent water resistance, oil resistance and heat sealing.

In addition, it was confirmed that the coating compositions of Comparative Examples 4 to 7 using acrylic emulsion instead of cellulose derivatives were not excellent in water resistance, oil resistance and heat sealing. In particular, in Comparative Examples 5 and 6, the secondary coating was not well performed on the primary coating layer, and the peeling phenomenon was severe after heat sealing.

In addition, Comparative Example 7 confirmed that the coating amount was small, so that the water resistance, oil resistance and heat sealing resistance were not excellent.

Claims (9)

delete A water-soluble coating composition further comprising 10 to 30 parts by weight of cellulose derivative, 1 to 10 parts by weight of plasticizer, 3 to 30 parts by weight of slip agent, and 0.5 to 50 parts by weight of dispersant based on 100 parts by weight of organic solvent. The organic solvent of claim 2, wherein the organic solvent is methyl benzene, ethyl acetate, ethyl acetate, methyl acetate, propyl acetate, benzene, chlorobenzene, chlorobenzene, ethanol. (Ethanol) and isopropanol (Isopropanol) at least one water-soluble coating composition selected from the group consisting of. The method of claim 2, wherein the cellulose derivative is selected from the group consisting of methyl cellulose, ethyl cellulose, hydroxypropylmethyl cellulose, cellulose acetate and nitro cellulose. Water-soluble coating composition of at least one selected. The plasticizer of claim 2, wherein the plasticizer is selected from the group consisting of Triacetine, Triethylcitrate, Dicyclohexyl phthalate, Epoxidized soybean oil, and Glycerol. 1 or more types of water-soluble coating composition. The method of claim 2, wherein the slip agent is paraffin wax emulsion (Paraffin wax emulsion), Lico wax emulsion (Poly wax wax), Polyethylene wax emulsion (Silicone emulsion), Stearic acid monomer (Stearic acid monomer) Water-soluble coating composition selected from the group consisting of). The water-soluble coating composition according to claim 2, wherein the dispersant is at least one selected from the group consisting of hydrophilic silica, acrylic emulsion, diester sulfosuccinate and urethane emulsion. Warming the organic solvent to 30 to 60 ° C .;
Adding 10 to 30 parts by weight of the 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 100 parts by weight of the organic solvent to the stirred mixture 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 100 parts by weight of the organic solvent and stirring the mixture containing the plasticizer;
Adding 0.5 to 50 parts by weight of the dispersant with respect to 100 parts by weight of the organic solvent and stirring: and
Method for producing a water-soluble coating composition comprising the step of aging the mixture containing the slip agent for 2 to 10 hours at 30 to 80 ℃. delete

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