KR20120045101A - Eco friendly and recyclable water soluble coating paper and manufacturing method thereof - Google Patents

Abstract

The present invention relates to an eco-friendly and renewable water-soluble coating paper and a method for manufacturing the same, and more particularly, it is biodegradable in the natural environment upon disposal after use, and does not burden the environment, and is easily dissociated in water or alkaline solutions to facilitate recycling. Hazardous heavy metals such as fluorescent brighteners, formaldehyde, cadmium, lead and arsenic provide water-soluble coatings that meet the criteria for packaging equipment and containers.
In addition, it is endowed with excellent oil resistance, water resistance and heat sealing, and can be utilized for manufacturing food packaging materials such as disposable cups, takeout containers, hamburger wrappers, chicken wrappers and ice cream containers.

Description

Eco-friendly and recyclable water soluble coating paper and manufacturing method

The present invention relates to an eco-friendly and renewable water-soluble coating paper and a method for manufacturing the same, which are easily dissociated into water or alkaline solution and do not put a load on the natural environment upon disposal after use.

Modern life has rapidly increased the use of disposable products due to the development of scientific technology, quality improvement of living standards and culture, and the pursuit of convenience, and the cups of vending machines, beverage packaging containers, cup noodles containers, takeout containers, Various disposable container packaging materials have been developed and used, such as ice cream containers, hamburger wrappers, and chicken wrappers.

Disposable container packaging material as described above is often used paper, in the case of paper to coat the inside with a waterproof material to solve the problem of hygroscopicity.

Polyethylene (PE) is widely used for coating the paper packaging material.

In general, polyethylene is a kind of plastic, which is light, rust and non-rotable, and is a chemical that is widely used in peripheral household goods due to its advantages such 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 packaging material using the same releases environmental hormones during use and disposal. There is a possibility. In addition, the polyethylene coating container packaging material has a disadvantage in that the recycling cost is increased because polyethylene that is not dissociated in water in the process of dissociation for recycling after use has to undergo a screening process.

As a result, pulp is continuously imported in the manufacture of packaging materials for paper containers, and there are limitations in terms of recycling resources and environmental destruction.In addition, soot generated during incineration causes air pollution, It takes hundreds of years for decomposition to become a major contributor to soil contamination. 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 disclosed a water-soluble wrapper 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, acrylic emulsion has a problem that takes a long time to dissociate in water during recycling, as well as water and oil easily penetrates the paper due to the hardened properties of the paper is damaged the coating film of the hinge portion.

It is an object of the present invention to provide a method for producing an eco-friendly and renewable water-soluble coating paper that is easily dissociated by water or alkali when disposed of after use, and is easily recycled and does not decompose in the natural environment and load on the natural environment.

Another object of the present invention is to provide a water-soluble coated paper.

In order to achieve the object of the present invention, (A) warming the organic solvent to 30 to 60 ℃; (B) adding 10 to 40 parts by weight of polyvinylidene chloride based on 100 parts by weight of the heated organic solvent and stirring at 30 to 60 ° C. for 30 to 150 minutes; (C) adding 0.005 to 0.1 parts by weight of fatty acid to 100 parts by weight of the organic solvent to the stirred mixture and stirring at 30 to 60 ℃ for 10 to 30 minutes; (D) adding 0.01 to 0.5 parts by weight of maleic anhydride to the mixture with respect to 100 parts by weight of an organic solvent and stirring at 30 to 60 ° C. for 10 to 30 minutes; (E) 0.2 to 2.0 parts by weight of a slip agent is added to the mixture containing maleic anhydride with respect to 100 parts by weight of an organic solvent and stirred at 30 to 60 ° C. for 15 to 60 minutes; (F) a coating solution preparation step of preparing a coating solution by aging the mixture at 20 to 80 ℃ for 2 to 10 hours; (G) coating the coating solution on a paper using a coating device such as a coater, and then dried and cooled to produce a coated paper to produce a coated paper; proposes an environmentally friendly and renewable water-soluble coating paper manufacturing method comprising a. .

Between step (E) and step (F), a dispersant is additionally added, and the dispersant is added in an amount of 0.01 to 1.0 parts by weight based on 100 parts by weight of an organic solvent, and 20 to 60 minutes under the same conditions as in step (E). It is preferable to stir.

Another object of the present invention to provide a water-soluble coating composition for paper coating prepared by the above production method.

By utilizing the present invention it is possible to produce a water-soluble coating paper given excellent water resistance, oil resistance and heat sealing.

In addition, the water-soluble coated paper of the present invention is excellent in printability and beautiful in appearance, and maintains water and oil resistance for 3 to 4 days in a heat-treated dry state, but when dissociated with stirring in water or alkaline solution during recycling, mechanical stirring treatment It dissociates quickly and can be easily recycled.

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

It will be described below in more detail with reference to the drawings.

1 is an exemplary flow chart of a method for producing an eco-friendly and renewable water-soluble coated paper of the present invention.

First, step (A) is a step of adding an organic solvent to the stirrer and warming to 30 to 60 ℃.

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

In step (B), polyvinylidene chloride is added to the heated organic solvent and stirred at a rate of 1,000 to 2,000 RPM for 30 to 150 minutes while maintaining 30 to 60 ° C. When the stirring time is less than 30 minutes, sufficient mixing is not made, and when the stirring time is more than 150 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 uniformly dissolve 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.

By including the polyvinylidene chloride in the coating solution, even if thinly applied to paper, excellent water resistance, oil resistance and heat sealing property can be imparted.

In step (C), the fatty acid is added to the mixture prepared in the above step so as to dissolve uniformly, and stirred at a speed of 1,000 to 2,000 RPM for 10 to 30 minutes while maintaining 30 to 60 ° C. If the temperature is less than 30 ℃ do not dissolve uniformly, if the temperature is over 60 ℃ organic solvent is volatilized to continue the process. In order to uniformly dissolve polyvinylidene chloride, the temperature must be maintained in steps (A) to (C).

If the stirring time is less than 10 minutes, polyvinylidene chloride is not uniformly dissolved, if the stirring time is more than 30 minutes, the organic solvent may be volatilized and there is a problem of viscosity increase of the mixture due to dissolution.

The fatty acid serves to uniformly melt polyvinylidene chloride, for example, lauric acid, palmitic acid and stearic acid as saturated fatty acids having C 12 to C 24 carbon atoms. ), Behenic acid, and one or two or more selected from lignoceric acid.

The fatty acid is used in 0.005 to 0.1 parts by weight, preferably 0.01 to 0.8 parts by weight based on 100 parts by weight of the organic solvent. If the fatty acid is less than 0.005 parts by weight, it is difficult to uniformly dissolve polymers such as polyvinylidene chloride, and if it is 0.1 parts by weight or more, uniform dissolution is inhibited by polymer aggregation.

In step (D), maleic anhydride is added to the prepared mixture, the mixture is further stirred and stirred at a speed of 1,000 to 2,000 RPM for 10 to 30 minutes while maintaining 30 to 60 ° C,

The maleic anhydride serves to more uniformly dissolve the polyvinylidene chloride together with the fatty acid so that the coating composition is easily coated on paper.

0.01 to 0.5 parts by weight, preferably 0.02 to 0.4 parts by weight, based on 100 parts by weight of maleic anhydride organic solvent. If it is less than 0.01 weight part, uniform dissolution of a polymer will be difficult, and if it is 0.5 weight part or more, economic efficiency will worsen.

Add the slip agent in step (E) and stir at a speed of 1,000 to 2,000 RPM for 15 to 60 minutes under the same conditions,

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 one or two selected from the group consisting of paraffin wax, rico wax, polyethylene wax, silicone, stearic acid monomer, and the like. The above is mentioned.

 The slip agent is used in an amount of 0.2 to 2.0 parts by weight, preferably 0.2 to 1.5 parts by weight, based on 100 parts by weight of the organic solvent. If the content of the slip agent is less than 0.2 parts by weight, the lubricity is lowered and sticking to each other due to the cracking phenomenon between the coating film occurs. If the content is more than 2.0 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.

In the step (F) it is aged at 20 to 200rpm at 20 to 200rpm for 2 to 10 hours to prepare a coating solution. If the mixture prepared in step (E) is not aged under the conditions of step (F), the intermolecular bonds are not stabilized and the solution is separated by release between the solvent and the solute.

In the step (G), the coating liquid obtained by aging is coated on paper using a coating apparatus such as a coater, and then dried to prepare coated paper having water, oil and heat sealing properties. Drying was followed by hot air drying with 50 to 200 ° C. hot air, which is commonly used, and then secondary drying while passing through a heating roller of 50 to 200 ° C., and finally winding after passing through a 0 to 30 ° C. cooling roller. The drying method is more preferably cooled through a cooling roller after drying through the heating roller 2 to 3 steps immediately after coating. The coating apparatus is not particularly limited, but may be a two to six-speed roller barb coater, a comma coater, a spray coater, a mesh or dot coater, a casting coater, a gravure coater, a dropping coater, an air knife coater, or the like. . In addition, the water-soluble coating liquid may be coated on a paper base or the like to produce a water-soluble coating paper provided with water resistance, oil resistance and heat sealing. 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.

In addition, between the steps (E) and (F), adding a dispersant to the mixture prepared in step (E) and stirring at a rate of 1,000 to 2,000 RPM for 20 to 60 minutes under the same conditions as step (E) You can add

The dispersing agent is to disperse materials such as polyvinylidene chloride polymer, increase suspension, and improve storage stability. Examples of the dispersant include hydrophilic silica, diester sulfosuccinate, and urethane emulsion. 1 type, or 2 or more types selected from the group can be mentioned.

The dispersant is used in an amount of 0.01 to 1.0 parts by weight, preferably 0.05 to 0.4 parts by weight, based on 100 parts by weight of the organic solvent. If the content of the dispersant is less than 0.05 parts by weight can not be expected dispersing effect, if the content is more than 0.5 parts by weight, the suspension is excellent, but it is not preferable economically.

Coating film coating amount of the coated paper of this invention is 5-20 g / m <2>, Preferably it is 7-15 g / m <2>. If the coating amount of the coating film is less than 5g / ㎡ it does not obtain excellent oil resistance, water resistance and heat sealing, if the coating amount is more than 20g / ㎡ it is more excellent in water resistance, oil resistance and heat sealing, but it is economical and Considering this is undesirable.

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

       When the hot air is 50 ° C. or less, the drying is not good, and when 200 ° C. or more, a part of the coated paper is folded.

       If the heating roller is 50 ° C. or less, the drying is not good. If the heating roller is 200 ° C. or more, a part of the coating liquid is entangled with the heating roller, thereby deteriorating the quality of the coated paper.

        If the cooling roller is 0 ℃ or less, the phenomenon that the coated paper is entangled in the roller is generated, if it is 30 ℃ or more, the cooling is not good, the coated paper is stuck, it can not proceed with the subsequent process.

Hereinafter, preferred examples are provided to help understanding of the present invention, but the following examples are provided to illustrate the present invention and the present invention is not limited thereto.

< Example  1-4>

Preparation of Water-soluble Coating Composition

&Lt; Example 1 >

30 parts by weight of methylbenzene and 50 parts by weight of tetrahydrofuran were added to a stirrer, heated to 40 ° C. using hot water, and 15 parts by weight of polyvinylidene chloride was added under the same temperature, followed by stirring at 1,000 rpm for 80 minutes. Under the same conditions as above, 0.02 parts by weight of behenic acid was added and stirred for 20 minutes, and then 0.05 parts by weight of maleic anhydride was added and stirred for 20 minutes. Further, 0.7 parts by weight of licowax was added and stirred for 20 minutes under the same conditions as above, and the remainder was tetrahydrofuran. The mixture was aged at 50 rpm for 5 hours while maintaining the 30 ℃ to prepare a water-soluble coating composition.

<Example 2>

The same procedure as in Example 1 except that lignoseric acid was used instead of behenic acid, and paraffin wax was used instead of licowax.

<Example 3>

30 parts by weight of methylbenzene and 50 parts by weight of tetrahydrofuran were added to a stirrer, heated to 40 ° C. using hot water, and 15 parts by weight of polyvinylidene chloride was added under the same temperature, followed by stirring at 1,000 rpm for 80 minutes. Under the same conditions as above, 0.02 parts by weight of behenic acid was added and stirred for 20 minutes, and then 0.05 parts by weight of maleic anhydride was added and stirred for 20 minutes. Also, 0.7 parts by weight of licowax was added and stirred for 20 minutes under the same conditions as above, 0.15 parts by weight of hydrophilic silica was added, followed by stirring for 30 minutes, and the remainder was tetrahydrofuran. The mixture was aged at 50 rpm for 5 hours while maintaining the 30 ℃ to prepare a water-soluble coating composition.

<Example 4>

In the same manner as in Example 3, lignoseric acid was used instead of behenic acid, and paraffin wax was used instead of licowax.

< Example  5 ~ 8>

receptivity Coated paper  Produce

Example 5

The coating liquid prepared in Example 1 was coated on food paper with a coating amount of 12 g / m 2 using a 120 mesh roller, and then firstly dried while passing through a 10 m hot air chamber at 100 ° C., and added by passing through a heating roller at 80 ° C. After drying, the resultant was passed through a cooling roller at 4 ° C., cooled and wound to prepare a coated paper wound in a roll type.

<Example 6>

The coating was carried out in the same manner as in Example 5, but using the water-soluble coating composition of Example 2 instead of the water-soluble coating composition of Example 1.

<Example 7>

In the same manner as in Example 5, but instead of the water-soluble coating composition of Example 1 to prepare a coated paper using the water-soluble coating composition of Example 3.

<Example 8>

In the same manner as in Example 5, but instead of the water-soluble coating composition of Example 1 to prepare a coated paper using the water-soluble coating composition of Example 4.

Experimental Example 1

Alkali dissociation and alkali dispersibility were confirmed in accordance with the method of EL606, which is an environmental mark certification standard, in order to confirm the ease of recycling and waste reduction characteristics of the water-soluble coated paper prepared according to Examples 5-8. According to the test method of EL606 (1) 1L of 0.5% NaoH solution was added to a 2L dissociation container, and 20 g of a sample chopped into 1 cm 2 or less of an eco-friendly adhesive eco-tile was added. (2) dissociate at 1,500 ± 100 RPM for 10 minutes at 55 ± 5 degrees, and then (3) stop the agitation and wash off the material attached to the vessel wall with 50 mL of alkaline solution and operate the stirrer to 1,500 ± 100 RPM. It was dissociated again for 10 minutes. (4) The process of (3) was repeated three times, and the sample solution was allowed to stand for 5 minutes and filtered through a metal mesh that is a 150 mesh filter medium. In addition, the remaining pulp sludge on the filter medium was washed five times with alkaline solution, and then the filter medium was washed five times with water of 80 ± 5 degrees. (5) The pulp sludge remaining on the filter medium was allowed to stand for 30 minutes at room temperature together with the filter medium, and then dried in a dryer of 105 ± 5 degrees for 2 hours to remove the remaining sodium hydroxide. (6) The dried filter medium was taken out and left to cool, and the pulp remaining on the filter medium was taken to evaluate alkali dissociation and dispersibility.

Example 5-8 Evaluation of Alkali Dissociation and Dispersibility of Water-Soluble Coated Paper division Judgment contents result Visual check of impurities in dried pulp Impurities other than rubber, plastic mass, and pulp none Pulp Adhesion on Dried Pulp Surface Press with hand or filter paper to check for stickiness No adhesion

From the results of Table 1, all four types of coated papers of Examples 4 to 8 do not contain impurities other than pulp, which is a criterion for “easy recycling, waste reduction,” according to EL606 packaging material standard, and does not show pulp stickiness. It was evaluated that it was dissociable or alkali dispersible, and it was found that it was easy to recycle and met waste reduction criteria.

Experimental Example 2

In order to determine whether the water-soluble coated paper prepared according to Example 7 contained heavy metals and harmful substances, the test was carried out according to the "standard specification of packaging of utensils and containers", and the results are shown in Table 2.

Test result of standard specification of utensil and container packing of Example 7 Item standard result Arsenic (mg / L) 0.1 or less Not detected Heavy metals (mg / L) 1.0 or less 0.1 Potassium permanganate consumption (mg / L) below 10 1.7 Lead (mg / kg) 100 or less Not detected Fluorescent Whitening Agent Not detected Not detected Formaldehyde (mg / L) 4.0 or less 0.5 Cadmium (mg / kg) 100 or less Not detected

From the results of Table 2, it can be seen that the apparatus is suitable for the standard packaging standards and is harmless to humans, and the heavy metal content is suitable.

<Experimental Example 3>

1. Water resistance and oil resistance: 5g each of water and cooking oil were coated on the coated surface of the water-soluble coated paper of Examples 5 to 8 and left at room temperature for 24 hours, 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 wet 5% or less on food paper)

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

(Triangle | delta): Poor (11-20 degrees of water and cooking oil wet on food paper)

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

2. Heat sealing property: Fold the water-soluble coating paper of Examples 5 to 8 so that the two coating surfaces faced each other, and then heat-sealed to a sealing strength of 5 using a heat sealing machine (Sambo Tech, SK-310). The heat-sealed water-soluble coated paper was completely submerged in water, and after 48 hours, the degree of heat-sealing surface drop 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%)

Water resistance, oil resistance and heat sealing test results of Examples 5-8 division Water resistance Oil resistance Heat sealing Example 5 ◎ ◎ ◎ Example 6 ◎ ○ ◎ Example 7 ◎ ◎ ◎ Example 8 ◎ □ ◎

As shown in Table 3 above, it was confirmed that the coated paper of Examples 5 to 8 according to the present invention is excellent in water resistance and heat sealing.

On the other hand, oil resistance was excellent in Examples 5 and 7, but Example 6 was a good level, Example 8 was a moderate level.

Eco-friendly and renewable water-soluble coating paper of the present invention can be utilized in the manufacture of food packaging materials, such as disposable cups, take-out containers, hamburger wrappers, chicken wrappers, ice cream containers, and can be easily recycled when disposed of after use.

Claims (7)

(A) warming the organic solvent to 30 to 60 ℃;
(B) adding 10 to 40 parts by weight of polyvinylidene chloride based on 100 parts by weight of the heated organic solvent and stirring at 30 to 60 ° C. and 1,000 to 2,000 RPM for 30 to 150 minutes;
(C) adding 0.005 to 0.1 parts by weight of fatty acid to 100 parts by weight of the organic solvent to the stirred mixture and stirring for 10 to 30 minutes at 30 to 60 ℃, 1,000 to 2,000 RPM;
(D) adding 0.01 to 0.5 parts by weight of maleic anhydride to the mixture with respect to 100 parts by weight of an organic solvent and stirring at 30 to 60 ° C. and 1,000 to 2,000 RPM for 10 to 30 minutes;
(E) 0.2 to 2.0 parts by weight of a slip agent is added to the mixture containing maleic anhydride with respect to 100 parts by weight of an organic solvent and stirred at 30 to 60 ° C. and 1,000 to 2,000 RPM for 15 to 60 minutes;
(F) aging the mixture containing the slip agent at 20 to 80 ℃, 20 to 200 RPM for 2 to 10 hours to prepare a coating composition
(G) The coating is coated on paper using a coating apparatus such as a coater, and then firstly dried with hot air at 50 to 200 ° C., secondly while passing through a heating roller at 50 to 200 ° C., and then 0 to 30 ° C. Manufacturing a coated paper by passing through a cooling roller; Method of producing a water-soluble coated paper comprising a. The method according to claim 1, wherein between (E) and (F), 0.01 to 1.0 parts by weight of the dispersant is added to 100 parts by weight of the organic solvent and stirred for 20 to 60 minutes under the same conditions as in step (E). Method for producing a water-soluble coating paper further comprising. The method of claim 1, wherein the organic solvent is methyl benzene, ethyl acetate, ethyl acetate, methyl acetate, propyl acetate, benzene, benzene, Chloro Benzene, Method for producing a water-soluble coating composition, characterized in that at least one of tetrahydrofuran, ethanol (Ethanol) and isopropanol (Isopropanol) According to claim 1, wherein the fatty acid is a C12-C24 saturated fatty acid lauric acid (Lauric acid), palmitic acid (Palmitic acid), stearic acid (stearic acid), behenic acid (Behenic acid), lignoser Method for producing a water-soluble coating composition, characterized in that at least one of acid (lignoceric acid) The method of claim 1, wherein the slip agent is any one or more of paraffin wax (Licoffin wax), rico wax (Lico wax), polyethylene wax (Silicone), stearic acid monomer (Stearic acid monomer) Method for producing a water-soluble coating composition The method of claim 2, wherein the dispersing agent is any one or more of hydrophilic silica, diester sulfosuccinate, and urethane emulsion. Water-soluble coated paper produced by the method of any one of claims 1 to 6.

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