KR102274458B1 - Method for prepararing eco-friendly packing paper for food and eco-friendly packing paper for food prepared thereby - Google Patents

Abstract

The present invention relates to an eco-friendly food packaging paper comprising applying an ^{organic nanoclay-dispersed water-soluble acrylic polyurethane coating solution 1 to 3 times in an amount of 3 to 6 g/m 2 on} the upper surface of a substrate made of coated or uncoated paper or kraft paper. It provides a manufacturing method, and the eco-friendly food packaging paper manufactured by the above method is excellent in oil resistance, water resistance, oxygen barrier property, moisture resistance, printability, heat sealing property, and has alkali dissociation property, so that it is easy to recycle (recycle).

Description

Manufacturing method of eco-friendly food packaging paper and obtained eco-friendly food packaging paper {METHOD FOR PREPARARING ECO-FRIENDLY PACKING PAPER FOR FOOD AND ECO-FRIENDLY PACKING PAPER FOR FOOD PREPARED THEREBY}

The present invention relates to a method for manufacturing eco-friendly food packaging paper and to the obtained eco-friendly food packaging paper, and more particularly, it is a high-barrier coating technology to which nano-dispersion technology is applied, which has excellent oil resistance, water resistance, oxygen barrier property, moisture-proof property, printability, heat sealing property, It relates to a method for manufacturing an eco-friendly food packaging paper that has alkali dissociation property and thus can be easily recycled (recycled), and the obtained eco-friendly food packaging paper.

With the development of modern society, food packaging and containers made of polymer resin materials such as PE and PET bring convenience to life with excellent functions and low prices, and have contributed greatly to the development of related industries. However, the polymer resin (plastic), which is the main component of food packaging, is being recognized as one of the biggest causes of environmental pollution due to the problem of disposal after use.

Polyethylene (PE) is generally a low-cost material with excellent food hygiene, elongation and processability, and is coated inside various food packaging papers and used for waterproofing purposes. There is a risk of releasing environmental hormones that are harmful to the human body.

In addition, in the process of dissociating polyethylene coated paper for recycling after use, polyethylene, which does not dissociate in water, has to undergo a separate screening process, thereby increasing the recycling cost. Accordingly, foreign currency is wasted due to the need for continuous import of pulp for the manufacture of packaging paper, and limits are exposed in terms of recycling of resources.

In addition, soot generated during waste incineration causes air pollution and is the main culprit of soil pollution because it takes hundreds of years to decompose even after landfilling. In particular, the polyethylene coating process requires polyethylene at a temperature of about 200°C. Due to the dissolution process of the chip and the use of volatile organic substances (VOCs) therefor, high cost, deterioration of the working environment, and serious environmental problems are caused.

On the other hand, among food packaging paper, hamburger wrapping paper or hamburger wrapping paper, which is a coated paper used to package hamburgers, is widely used in hamburger stores and at home, but most of them are disposed of as garbage, so there are many methods for recycling them together with disposable paper cups. is being explored

Most of the prior art devised in relation to such a hamburger wrapper use a wrapping paper of a common material, but are biased toward designing and modifying the structure for the convenience of cutting and eating, and improving the function of the wrapping paper for hamburger itself through a chemical method Research and development related to recycling or recycling is still lacking.

Patent Document 1 (Korean Patent Publication No. 10-2013-0069253) discloses a hamburger wrapper made by adding two perforated lines to the hamburger wrapper so that users can eat it more easily and hygienically, but a new coating material or coating There is no special mention about improving the basic functions of the hamburger wrapping paper, such as water resistance and oil resistance through the introduction of the method.

In Patent Document 2 (Korean Patent No. 10-1565714), alkali treatment by coating the base paper in an optimal way using two or more water-soluble resins, a water-soluble coating solution of a specific formulation including a curing agent in a predetermined equivalent ratio, and an antibacterial component Manufacture of eco-friendly alkali-dissociable hamburger wrapping paper that can be easily recycled and efficiently and economically manufactured in a short drying time with excellent water and oil resistance, adhesion (heat sealing), slip and antibacterial properties method is disclosed.

Under these circumstances, the present invention has the same effect as polyethylene in the manufacturing process of hamburger wrapping paper, and also uses a water-soluble cellulose technology-based coating solution that can be recycled and produces eco-friendly hamburger wrapping paper through this, so that the pulp used in the hamburger wrapping paper can be recycled. Because it does not require a high-temperature process of about 200°C, it reduces process costs and fundamentally eliminates the generation of volatile organic substances (VOCs) and air pollution related thereto. It is to provide a new eco-friendly hamburger wrapping paper and a manufacturing method thereof that can protect the health of people and provide an eco-friendly working environment.

Domestic Patent Publication No. 10-2013-0069253 Domestic Registered Patent No. 10-1565714

The present invention is harmless to the human body by supplementing the shortcomings of the existing hamburger wrapping paper, and has excellent resource saving (reduction of weight, reusability, recyclability, recyclability, ease of disposal), eco-friendliness during incineration, and ease of decomposition at landfill, thereby protecting the environment. An object of the present invention is to provide an eco-friendly hamburger wrapping paper using an eco-friendly coating solution imparted with alkali dissociation to protect and a manufacturing method thereof.

The present invention has been devised to solve the above problems, and provides a method for manufacturing an eco-friendly hamburger wrapping paper comprising coating a packaging substrate with a nano-clay dispersed water-soluble acrylic polyurethane coating solution developed by the present inventors, specifically With the following steps:

(1) preparing a water-soluble acrylic polyurethane coating solution dispersed in nano clay;

(2) forming a coating layer by applying the nanoclay-dispersed water-soluble acrylic polyurethane coating solution on the upper surface of a packaging substrate selected from coated paper, uncoated paper or kraft paper; and

(3) drying the coating layer with an ultraviolet drying device comprising a UV lamp, a hot air device, and a cooling cooling device;

Including, spraying hot air for 1 to 5 minutes at a temperature of 50 to 200 ° C in the hot air device, and while the cooling wind is sprayed from the cooling cooling device, rapidly heat the coating layer at a temperature of -10 to 10 ° C for 1 to 3 minutes characterized by cooling.

In addition, the step of preparing the nano-clay dispersed eco-friendly water-soluble acrylic polyurethane coating solution may include the following steps:

(a) preparing a prepolymer by mixing polyol, dimethylol propionic acid (DMPA) and isocyanate;

(b) Neutralizing the prepolymer with a neutralizing agent diluted in N-methylpyrrolidone (NMP) solution, adding distilled water to the neutralized prepolymer for water dispersion, and adding a chain extender to prepare water-dispersed polyurethane step;

(c) adding an acrylic monomer and an initiator to the water-dispersed polyurethane, followed by stirring to prepare a water-soluble acrylic polyurethane; and

(d) dispersing the clay treated with an organic agent in the water-soluble acrylic polyurethane.

The present inventors found that the wrapping paper prepared by the above manufacturing method is useful as an eco-friendly hamburger wrapping paper because it has excellent oil resistance, water resistance, oxygen barrier properties, moisture resistance, printability, and heat sealing property, and has alkali dissociation property, so that it is easy to reproduce (recycle). The present invention was completed.

The eco-friendly hamburger wrapping paper manufactured according to the present invention has excellent oil resistance, water resistance, oxygen barrier property, moisture proof property, printability, heat sealing property, and has alkali dissociation property, so that it is easy to recycle (recycle).

1A is a flowchart showing a manufacturing process of an eco-friendly hamburger wrapper according to the present invention, and FIG. 1B is an example of a manufacturing process of an eco-friendly nano clay-dispersed water-soluble acrylic polyurethane coating solution for manufacturing an eco-friendly hamburger wrapper according to the present invention This is a flow chart showing
2A and 2B are conceptual diagrams illustrating a concept related to securing barrier properties due to expansion of a permeation path in a composite to which nanoclay is applied.
3a and 3b are test results tested according to the physical properties of the wrapping paper for hamburger using the coating solution according to the present invention, and the standard standards for equipment and containers and packaging.

The first object of the present invention is (step 1) to prepare a nano-clay-dispersed water-soluble acrylic polyurethane coating solution, and (step 2) to the upper surface of a substrate for hamburger wrapping paper made of coated or uncoated paper or kraft paper, the nano-clay- forming a coating layer by applying a dispersed water-soluble acrylic polyurethane coating solution; And (step 3) to provide a method for manufacturing an eco-friendly hamburger wrapping paper comprising the step of drying the coating layer with an ultraviolet drying device comprising a UV lamp, a hot air device, and a cooling cooling device,

In the hot air device, hot air is sprayed at a temperature of 50 to 200 ° C. for 1 to 5 minutes, and the coating layer is rapidly cooled to a temperature of -10 to 10 ° C. for 1 to 3 minutes while the cooling wind is sprayed from the cooling cooling device. do.

According to one preferred embodiment of the present invention, the coating and drying process may be repeated at least once, preferably 1 to 3 times.

A second object of the present invention is to provide an eco-friendly hamburger wrapper manufactured by the method for manufacturing the eco-friendly hamburger wrapper.

The present invention will be described in more detail below.

The nano-clay-dispersed water-soluble acrylic polyurethane coating solution that can be used in the present invention may be prepared by dispersing the nano-clay or organic nanoclay in the water-soluble acrylic polyurethane coating solution.

According to one preferred embodiment of the present invention, the nanoclay-dispersed or organic nanoclay-dispersed water-soluble acrylic polyurethane coating solution can be prepared by a manufacturing method comprising the following steps:

(a) preparing a prepolymer by mixing a polyol, dimethylolpropionic acid (DMPA) and an isocyanate;

(b) Neutralizing the prepolymer with a neutralizing agent diluted in N-methylpyrrolidone (NMP) solution, adding distilled water to the neutralized prepolymer for water dispersion, and adding a chain extender to prepare water-dispersed polyurethane step;

(c) adding an acrylic monomer and an initiator to the water-dispersed polyurethane, followed by stirring to prepare a water-soluble acrylic polyurethane; and

(d) dispersing the clay treated with an organic agent in the water-soluble acrylic polyurethane.

Step (a) of preparing the prepolymer may be performed including the following steps:

(a1) dissolving 15 to 25 parts by weight of a polyol based on 100 parts by weight of the prepolymer at 60 to 80° C. in a vacuum oven, followed by stirring by replacing the internal air with nitrogen;

(a2) adding and stirring 15 to 25 parts by weight of dimethylolpropionic acid based on 100 parts by weight of the prepolymer; and

(a3) After stirring by adding 50 to 65 parts by weight of isocyanate based on 100 parts by weight of the prepolymer, lowering the temperature to 45 to 55°C.

The polyol may be selected from polyether polyols, preferably polytetramethylene glycol (PTMG), and may be used in an amount of 15 to 25 parts by weight based on 100 parts by weight of the water-soluble acrylic polyurethane. When the amount of the polyol used is less than 15 parts by weight, there is a fear that the cohesive force may decrease, and if it exceeds 25 parts by weight, there is a fear that the hydrolysis resistance may decrease.

The dimethylol propionic acid (DMPA) may be used in an amount of 15 to 25 parts by weight based on 100 parts by weight of the water-soluble acrylic polyurethane. When the amount thereof is less than 15 parts by weight, there is a fear that the stability of water dispersion may decrease, and if it exceeds 25 parts by weight, there is a fear that the hydrolysis resistance may decrease.

The isocyanate may be selected from the group consisting of aliphatic diisocyanates, cycloaliphatic and aromatic diisocyanates. As non-limiting examples of aliphatic or cycloaliphatic diisocyanates, mention may be made of 4,4-dicyclohexanemethane diisocyanate (H12MDI), isophorone diisocyanate (IPDI), 1,4-cyclohexane diisocyanate (CHDI). and 4,4'-diphenylmethane diisocyanate (MDI), 2,4- or 2,6-toluene diisocyanate (TDI) may be mentioned as non-limiting examples of aromatic diisocyanates. Preferably isophorone diisocyanate (IPDI) can be used. Isocyanates such as IPDI may be used in an amount of 50 to 65 parts by weight of polyol based on 100 parts by weight of water-soluble acrylic polyurethane, and if it is out of the above range, there is a risk that polyurethane may not be sufficiently synthesized or water dispersion stability may be reduced.

Step (b) of preparing the water-dispersed polyurethane may be performed including the following steps:

(b1) neutralizing the prepolymer by mixing 25 to 45 parts by weight of the prepolymer, 1 to 3 parts by weight of an N-methylpyrrolidone (NMP) solution, and 2 to 6 parts by weight of a neutralizing agent based on 100 parts by weight of the water-soluble polyurethane dispersion ;

(b2) stirring while dropping 40 to 60 parts by weight of distilled water; and

(b3) adding 5 to 15 parts by weight of a chain extender and stirring.

The neutralizing agent may be selected from the group consisting of triethylamine (TEA), trimethylamine (TMA) or sodium hydroxide (NaOH), preferably triethylamine (TEA) is used. When the amount of the neutralizing agent used is less than 2 parts by weight, there is a fear that dispersion stability in water may decrease, and if it exceeds 6 parts by weight, there is a fear that storage stability may be reduced, and there is a possibility that physical properties may be deteriorated by causing an addition reaction.

Ethylenediamine (EDA) may be mentioned as the chain extender. If the amount of the chain extender used is less than 5 parts by weight, there is a fear that the chain extension effect may be insignificant, and if it exceeds 15 parts by weight, storage stability may be deteriorated.

In the step (c) of preparing the water-soluble acrylic polyurethane, 70 to 85 parts by weight of the water-dispersed polyurethane, 10 to 25 parts by weight of the acrylic monomer, and 1 to 3 parts by weight of an initiator are added and stirred with respect to 100 parts by weight of the water-soluble acrylic polyurethane. It can be done by

The acrylic monomer may be selected from the group consisting of methyl methacrylate, methacrylate, acrylonitrile, ethyl acrylate, ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, methacrylonitrile and vinyl acetate. and, preferably, methyl methacrylate (MMA) may be used. When the amount thereof is less than 10 parts by weight, there is a fear that the effect of improving durability and water resistance may be insufficient, and if it exceeds 25 parts by weight, there is a fear that storage stability may be lowered.

The initiator for polymerization can be used in an amount of 1 to 3 parts by weight. The initiator is not particularly limited, and for example, 2,2'-azo-bis(isobutyronitrile) (AIBN) or 2,2'-azo-bis(methylbutyronitrile) (ABN) and the like may be mentioned. and preferably AIBN. On the other hand, when the amount of the initiator used is less than 1 part by weight, the efficiency of the initiator is lowered and the reaction does not proceed easily, and when it is used in excess of 3 parts by weight, there is a problem in that a gel is generated due to an instantaneous exothermic reaction.

The step (d) of dispersing the clay treated with the organic agent in the water-soluble acrylic polyurethane may be performed by dispersing 2-5% of the clay treated with the organic agent in 95-98 wt% of the water-soluble acrylic polyurethane.

The clay treated with the organic agent may be, for example, montmorillonite modified with a quaternary ammonium salt. Examples of the quaternary ammonium salt include dimethylbenzyl hydrogenated tallow quaternary ammonium, dimethyl dihydrogenated tallow quaternary ammonium, and methyl tallow bis-2-hydroxyethyl quaternary ammonium. (methyl tallow bis-2-hydroxyethyl quaternaryammonium), dimethyl hydrogenatedtallow 2-ethylhexyl quaternary ammonium, etc. may be mentioned, double dimethyl hydrogenated tallow 2-ethylhexyl quaternary ammonium (Dimethyl hydrogenated tallow 2-ethylhexylquaternaryammonium) is most preferable.

A lot of research has been done on polymer nanocomposite materials using Pristinemonmorillonite (PM), a clay mineral with a layered structure. Nanocomposites containing montmorillonite, known as nanoclay, are known as inorganic additives that can enhance mechanical properties as well as provide various advantages such as excellent heat resistance, low gas permeability, and flame retardancy. When this nanoclay is prepared as a composite material, when it is uniformly dispersed in a nanoscale in a polymer matrix, the properties of the polymer/nanoclay composite material are improved. Because nanoclay has strong hydrophilicity, it is often difficult to disperse when added to a polymer, so the surface of the clay is modified with an organic agent and then mixed and added.

The method for manufacturing an eco-friendly hamburger wrapping paper according to the first object of the present invention includes the following steps:

(Step 1) preparing a nano-clay-dispersed water-soluble acrylic polyurethane coating solution, for example, dispersing nano-clay in a water-soluble acrylic polyurethane coating solution to prepare a nano-clay-dispersed water-soluble acrylic polyurethane coating solution;

(Step 2) On the upper surface of the substrate made of coated paper, uncoated paper or kraft paper, the above-mentioned nano clay-dispersed water-soluble acrylic polyurethane coating solution, for example, 2-7 g/m ² , specifically 3-6 g/m ² , Forming a coating layer by applying preferably in an amount of 4-5 g/m ^{2 ;} and

(Step 3) drying the coating layer with an ultraviolet drying device comprising a UV lamp, a hot air device, and a cooling cooling device;

In this case, the hot air is sprayed at a temperature of 50 to 200° C. for 1 to 5 minutes from the hot air device, and the cooling wind is sprayed from the cooling cooling device while the coating layer is heated at a temperature of -10 to 10° C. for 1 to 3 minutes. It is characterized by rapid cooling.

The nano-clay-dispersed water-soluble acrylic polyurethane coating solution that can be used in the present invention may be prepared by dispersing the nano-clay or organic nanoclay in the water-soluble acrylic polyurethane coating solution. Such nanoclay or organic nanoclay-dispersed water-soluble acrylic polyurethane coating solution is, for example, manufactured as described in Korean Patent Application No. 10-2018-0021005 (application date February 22, 2018, unpublished) by the present inventors It may be prepared by the method.

In the present invention, coated paper, uncoated paper or kraft paper may be used as the substrate for hamburger wrapping paper, but is not limited thereto. The coated paper may be selected from the group consisting of art paper, SC manila paper, ivory manila paper, royal ivory manila paper, and cast coated paper (CCP) paper, and the uncoated paper may be selected from the group consisting of white paper, thin leaf paper and TOP manila paper.

The UV drying device is a device to which sterilization and sterilization treatment, constant temperature, and constant humidity method are applied, and by irradiating UV rays to the coated hamburger wrapper, and internal curing by UV rays, the coating layer is completely dried. In addition, the hardness of the coating layer is improved by changing the physical properties of the coating layer by the internal curing action.

In addition, it is preferable to spray the hot air for 1 to 5 minutes at a temperature of 50 to 200 ℃ in the hot air device. If the hot air temperature and time is less than 50 ° C. and 1 minute, there is a problem in that the inside of the coating layer is not dried, and when it is 200 ° C. and more than 5 minutes, a problem occurs that a part of the coated hamburger wrapper is stained.

In addition, while cooling wind is sprayed from the cooling cooling device, the coating layer is rapidly cooled to a temperature of -10 to 10° C. for 1 to 3 minutes to prevent curling of the hamburger wrapper. When the cooling temperature and time are -10°C and less than 1 minute, there is a problem that the coated hamburger wrapper sticks to the roller provided in the UV drying device, and when it is 10°C and more than 3 minutes, a part of the coated hamburger wrapper is folded There is a problem with losing

The coating solution is characterized in that it is coated by selecting any one of knife coating coating, reverse roll coating, air knife coating, and wire rod coating method.

In the knifeting coating method, the coating thickness and amount of the coating material can be controlled by a knife or blade, and can be adjusted according to the number of meshes of the transfer roll. The quality of the coating depends on the angle and shape of the knife, the speed of passing through the web, and the flow characteristics of the coating solution.

In the reverse roll coating method, in the coating method, when the coating resin is applied to the web by a coating roll and then passes through a metering roll and a rubber backing roll, the excess coating solution is removed and the entire coated film is treated with a smooth surface. The thickness is constantly adjusted. The surface of the backing roll is made of an elastic material such as rubber, and it is possible to control the coating thickness by controlling the pressure of the nip. The higher the pressure of the nip and the faster the rotational speed of the roll, the greater the amount of coating agent removed. It is applied in consideration of the thickness of the coating, the viscosity of the coating solution, the amount of solids, thixotropy, and tack. .

The air knife coating method is a method of removing excess coating liquid by colliding laminar flow air on the paper surface. When the paper surface comes into contact with the coating roll rotating on the pan with the coating material, a predetermined amount of coating thickness is measured in advance. is applied At this time, the amount of coating resin applied depends on the collision speed and angle of the air, the viscosity of the coating solution, and the movement speed of the paper. The advantage of this method is that it uses air pressure without a coating knife, so it is coated uniformly regardless of the unevenness of the paper surface, and excellent coating effect occurs even if the thickness of the coating is thin.

In the present invention, the nano clay-dispersed water-soluble acrylic polyurethane coating solution is usually ^{2 to 7} g/m 2 , specifically 3 to 6 g/m ² , preferably 4 to 5 g/m ^{2 By} applying an amount of 4 to 5 g/m 2 to form a coating layer can be formed, because a small amount of coating is required to ensure production speed. In addition, when a water-soluble liquid is coated on paper, if a large amount is applied, curl (drying phenomenon) of the paper fabric may occur, but coating in an amount within the above range can significantly prevent this problem.

According to one preferred embodiment of the present invention, the coating layer may be formed in a multi-layer structure of one or more layers, specifically two or more layers, preferably three or more layers. The hamburger wrapping paper having a coating layer having a multi-layer structure of two or three or more layers has better mechanical properties such as oil and water resistance and thermal bonding strength compared to wrapping paper having a single-layer coating layer of the same thickness.

The coating layer having such a multilayer structure may be formed by repeating the coating process 1 to 3 times or more, for example, it may be formed by performing 1 to 3 degrees printing or coating according to the coating process. For reference, if 12-15 g/m ² of the coating solution is coated at one time in a one-time or one-time coating process, the water resistance, oil resistance, barrier properties, and heat sealing properties required after coating are lower than when coating three consecutive times or three times. Therefore, it is possible to prevent deterioration of the physical properties of the resulting coated paper by repeating the coating and drying process by dividing it into 1 to 3 times.

Hereinafter, the present invention will be described in more detail through Examples and Experimental Examples. However, these examples are only for helping the understanding of the present invention, and the scope of the present invention is not limited to these examples in any sense.

Preparation of reagents

The polyol used in the preparation of the water-soluble polyurethane aqueous dispersion was ether-type polytetramethylene glycol (PTMG) (Mw=1,800 g/mole) and vacuum-dried at 1 mmHg and 60° C. for about 10 hours or more to remove moisture. . In order to introduce a hydrophilic functional group in the urethane, dimethylolpropionic acid (DMPA) was used as it was without further purification. Triethylamine (TEA) was used as a neutralizing agent, and ethylenediamine (EDA) was used as a chain extender.

Methyl methacrylate (MMA) was used as the acrylic monomer used in preparing the acryl-polyurethane hybrid, 2,2'-azobisisobutyronitrile (AIBN) was used as the initiator, and N-methyl-2 was used as the solvent. -Pyrrolidone (NMP) was used

Nano clay is montmorillonite from Southern Clay Product, pure montmorillonite (PM) with a cation exchange capacity (CEC) of 92.6 meq/100g, and Cloisite 30B (CEC: 90.0 meq/100g) and Cloisite 25A whose surface has been modified with an organic agent. (CEC: 95.0 meq/100 g) was used. 30B and 25A are nanoclays modified with methyl tallow bis-2-hydroxyethyl quaternary ammonium and dimethyl dehydrogenated tallow 2-ethylhexyl quaternary ammonium, respectively.

<Preparation Example 1> Preparation of water-soluble acrylic urethane hybrid dispersion

First, waterborne polyurethane dispersions (WPUDs) were synthesized. It is produced in a 'two shot process' method in which the prepolymer is first reacted with polytetramethylene glycol (PTMG) and dimethylol propionic acid (DMPA) and then isocyanate is added during the mixing process. The two inlets of the stirrer are purged with nitrogen, the other inlet is blocked, and distilled water is added dropwise.

1) Preparation of NCO-prepolymer

First, put polytetramethylene glycol (PTMG) in a stirrer and melt it as it is in a vacuum oven (100° C.), and then install it in an oil bath. The impeller speed of the stirrer is fixed at 100 rpm, and the air inside the stirrer is replaced with nitrogen for 30 minutes to start the reaction. Then, dimethylolpropionic acid (DMPA) dried in a vacuum in advance is put into a stirrer without changing the reaction conditions and dissolved in PTMG.

After stirring for about 1 hour, NMP and IPDI are added. After stirring as it is for about 1 hour, the temperature is lowered to 50° C., and then stirred for 1 hour more to obtain NCO-prepolymer.

PTMG DMPA NMP IPDI Total (wt%) 18 22 3 57 100

2) Preparation of water-soluble polyurethane dispersion

After neutralizing TEA diluted with NMP solution into the NCO-prepolymer prepared above, a certain amount of distilled water is added dropwise at a constant speed and the stirring speed is increased to 300 rpm. After that, EDA is put in a stirrer and stirred for a total of 3 hours in that state to finally obtain a water-soluble polyurethane dispersion.

NCO-prepolymer NMP TEA Distilled water EDA Total (wt%) 34 2 4 50 10 100

3) Preparation of acrylic-urethane hybrid dispersion

Prepare the water-soluble polyurethane dispersion prepared in the above manner. After stabilizing the MMA and the water-soluble polyurethane dispersion at a high speed of 1500 rpm for 30 minutes with the impeller speed of the stirrer, it was installed in an oil bath and replaced with nitrogen for 30 minutes. When the inside of the stirrer is conditioned under nitrogen, a solution of AIBN is added to MMA and stirred at 300 rpm for 1 hour to prepare waterborne acrylic-urethane hybrid dispersions (WAUDs).

polyurethane dispersion MMA AIBN Total (wt%) 78 20 2 100

<Preparation Example 2> Preparation of nano clay dispersion water-soluble acrylic polyurethane coating solution

To the liquid water-soluble acrylic-urethane hybrid dispersion solution prepared in Preparation Example 1, montmorillonite (Cloisite 30B or Cloisite 25A), whose surface was modified with an organic agent based on the total weight, was added in an amount of 2.0 to 5.0 wt% based on the total weight, and then at room temperature. was stirred to prepare a nanoclay dispersed water-soluble acrylic polyurethane coating solution.

As a result of examining the interlayer spacing of the nanoclay, the interlayer distance of the nanoclay of Cloisite 25A increases, so that it is effectively dispersed in the resin. As a result of measuring the thermal properties of the acrylic resin/nanoclay composite material, the glass transition temperature of the NAD resin including Cloisite 25A is also high. Cloisite 25A was observed to be superior to the storage modulus, so it is most effective to add Cloisite 25A as nanoclay.

<Example 1> 1 coat coating

A substrate is put in a dry laminating coating machine, and the coating solution prepared in Preparation Example 2 is coated on the upper surface of the substrate at a coating amount of 12 g/m 2 to form a coating layer, and then the substrate is dried in an ultraviolet drying device, and hot air while irradiating with ultraviolet rays The device was dried by spraying hot air at 100° C. and 3 minutes, and then dried by rapid cooling at 5° C. and 3 minutes in a cooling cooling device to obtain an eco-friendly hamburger wrapper.

<Example 2> 2 coat coating

A substrate is put into a dry laminating coating machine, and the coating solution prepared in Preparation Example 2 is coated on the upper surface of the substrate at a coating amount of 6 g/m 2 to form a first coating layer, and then 6 g/m 2 of the coating solution is applied to the upper surface of the first coating layer. A second coating layer was formed by coating with a coating amount of Then, the substrate on which the first coating layer and the second coating layer are formed is dried in an ultraviolet drying device, and dried by spraying hot air at 100° C. and 3 minutes in a hot air device while irradiating with UV light, and then at 5° C. and It was dried by rapid cooling for 3 minutes to obtain an eco-friendly hamburger wrapping paper.

<Example 3> 3 coat

After putting a substrate in a dry laminating coating machine, and coating the coating solution prepared in Preparation Example 2 on the upper surface of the substrate at a coating amount of 4 g/m 2 to form a first coating layer, 4 g/m 2 of the coating solution on the upper surface of the first coating layer After forming a second coating layer by coating with a coating amount of , the coating solution was again coated on the upper surface of the second coating layer at a coating amount of 4 g/m 2 to form a third coating layer. Then, the substrate on which the first coating layer, the second coating layer, and the third coating layer are formed is dried in the ultraviolet drying device, and dried by spraying hot air at 100° C. and 3 minutes in a hot air device while irradiating with ultraviolet rays, and then cooling the cooling device It was dried by rapid cooling at 5° C. and 3 minutes to obtain an eco-friendly hamburger wrapping paper.

<Experimental Example 1>

The hamburger wrappers prepared in Examples 1 to 3 were tested for physical properties under the same conditions, and the results are summarized in [Table 4] below.

Test Items Example 1 Example 2 Example 3 Food packaging safety fitness fitness fitness Alkali dissociation and dispersibility has exist has exist has exist Surface roughness, smoothness △ ○ ◎ induction resistance △ ○ ◎ domestic water supply ○ ○ ◎ speculation ○ ○ ◎ moisture permeability ○ ○ ◎ heat bonding strength × △ ◎ Legend) ◎ Very good, ○ Excellent, △ Fair, × Poor
^{WVTR: ◎ <30mg / m 2,} ○ 30~50mg / m 2, △ 50~200mg / m 2, ×> 200mg / m 2
Permeability: ◎ <5cc/m ² , ○ 5∼30cc/m ² , △ 30∼60cc/m ² , × > ^{60cc/m 2}
Thermal bonding strength: ◎ >1,200g/37mm, ○ 900~1,200g/37mm, △ 800~900g/37mm, × <800g/37mm

<Test method>

Surface roughness (smoothness): KSM ISO 5627:2011

Induction resistance: KS M 7124:2008

Domestic water supply: KS M 7025:2012:12

Speculative degree: KS M 7020:2006:11

Moisture permeability (weight method): KS M ISO 2528

Thermal bonding (heat sealing) strength: self-test

The surface roughness of the eco-friendly hamburger wrapper prepared by the present invention is tested by the method of KSM ISO 5627:2011, the oil resistance is tested by the method of KS M 7124:2008, and the water resistance is tested by the method of KS M 7025:2012:12 And, the air permeability was tested by the method of KS M 7020:2006:11, the moisture permeability was tested by the method of KS M ISO 2528, and the thermal adhesion (heat sealing) strength was tested through a self-test. Through the above test, it was found that the hamburger wrapping paper prepared in Example 3 had superior physical properties compared to the case where the hamburger wrapping paper was coated by the methods of Examples 1 and 2.

In addition, the eco-friendliness of the hamburger wrappers of Examples 1 to 3 prepared by the present invention did not contain impurities in the alkali dissociation and dispersibility tests of the Korean Ministry of Environment's environmental label target products and certification standards (EL 103:2007). , no adhesion was observed. Thus, a level of reusability has been achieved.

In addition, the hamburger wrapping paper manufactured by the present invention can be safely used as a hamburger wrapping paper in conformity with the test standards of the processing materials of the Ministry of Food Safety and the standards and specifications for the food safety mechanism and container packaging.

<Experimental Example 2>

In order to check whether the eco-friendly hamburger wrapping paper prepared according to Examples 1 to 3 contains heavy metals and harmful substances, it was tested according to "Standard Specifications for Appliances and Containers and Packaging", and the results are shown in [Table 5] below.

Key performance indicators unit result Residual PCBs mg/kg not detected Residual Lead (Pb) mg/kg non-detection Residual cadmium (Cd) mg/kg non-detection Residual mercury (Hg) mg/kg non-detection Residual hexavalent chromium (Cr+6) mg/kg 2 Elution lead (Pb) mg/L non-detection Elution calcium permanganate consumption mg/L One eluted methyl methacrylate mg/L non-detection Evaporation residue (4% acetic acid) mg/L 6 Elution Evaporation Residue (Water) mg/L 3 Elution evaporation residue (n-heptane) mg/L 11

Test standard: [MFDS] Standard for food utensils and containers and packaging standards

From the results of [Table 5], it was found that it was harmless to the human body and had a suitable content of heavy metals because it was suitable for the standards of equipment and containers and packaging.

Above, what has been described in the present invention is only an embodiment for an eco-friendly water-soluble coated paper using a multi-layer coating technology having oil resistance, water resistance, moisture resistance and heat sealing property and a method for manufacturing the same, the present invention is not limited to the above embodiment, but each other It can be implemented in various other forms, and only this embodiment is provided so that the disclosure of the present invention is complete, and to completely inform those of ordinary skill in the art to which the present invention belongs, the scope of the invention, The invention is only defined by the scope of the claims.

Claims (9)

(1) preparing a nano clay-dispersed water-soluble acrylic polyurethane coating solution;
(2) forming a coating layer by applying the nano-clay-dispersed water-soluble acrylic polyurethane coating solution to the upper surface of a substrate made of coated or uncoated paper or kraft paper in an ^{amount of 3 to 6 g/m 2 ;}
(3) A method for manufacturing an eco-friendly hamburger wrapping paper comprising the step of drying the coating layer with an ultraviolet drying device comprising a UV lamp, a hot air device, and a cooling cooling device,
- In the hot air device, hot air is sprayed at a temperature of 50 to 200 ° C. for 1 to 5 minutes, and the coating layer is rapidly cooled to a temperature of -10 to 10 ° C. for 1 to 3 minutes while the cooling wind is sprayed from the cooling cooling device,
- The nano clay-dispersed water-soluble acrylic polyurethane coating solution,
(a) preparing a prepolymer by mixing polyol, dimethylol propionic acid (DMPA), N-methylpyrrolidone (NMP) solution and isocyanate;
(b) Neutralizing the prepolymer with a neutralizing agent diluted in N-methylpyrrolidone (NMP) solution, adding distilled water to the neutralized prepolymer to water dispersion, and adding a chain extender to prepare water-dispersed polyurethane step;
(c) adding an acrylic monomer and an initiator to the water-dispersed polyurethane, followed by stirring to prepare a water-soluble acrylic polyurethane; and
(d) dispersing the clay treated with an organic agent in the water-soluble acrylic polyurethane;
- The step (a) of preparing the prepolymer is
(a1) dissolving 15 to 25 parts by weight of a polyol based on 100 parts by weight of the prepolymer at 60 to 80° C. in a vacuum oven, followed by stirring by replacing the internal air with nitrogen;
(a2) adding and stirring 15 to 25 parts by weight of dimethylolpropionic acid based on 100 parts by weight of the prepolymer; and
(a3) adding 1 to 5 parts by weight of an N-methylpyrrolidone (NMP) solution and 50 to 65 parts by weight of an isocyanate based on 100 parts by weight of the prepolymer, followed by stirring, and lowering the temperature to 45 to 55° C. characterized by,
A method for manufacturing eco-friendly hamburger wrapping paper using nano clay-dispersed water-soluble acrylic polyurethane coating solution.
The method of claim 1,
Nano clay-dispersed, characterized in that the coating layer is formed into a multi-layer structure by repeating the steps of applying and drying the nano clay-dispersed water-soluble acrylic polyurethane coating solution in ^{an amount of 3 to 6 g/m 2 at least once} Manufacturing method of eco-friendly hamburger wrapping paper using water-soluble acrylic polyurethane coating solution.
delete delete The method of claim 1,
Step (b) of preparing the water-dispersed polyurethane,
(b1) neutralizing the prepolymer by mixing 25 to 45 parts by weight of the prepolymer, 1 to 3 parts by weight of an N-methylpyrrolidone (NMP) solution, and 2 to 6 parts by weight of a neutralizing agent based on 100 parts by weight of the water-soluble polyurethane dispersion ;
(b2) stirring while adding 40-60 parts by weight of distilled water dropwise; and
(b3) A method for producing an eco-friendly hamburger wrapper using a nano clay-dispersed water-soluble acrylic polyurethane coating solution, characterized in that it comprises the step of adding 5 to 15 parts by weight of a chain extender and stirring.
The method of claim 1,
In the step (c) of preparing the water-soluble acrylic polyurethane, 70 to 85 parts by weight of the water-dispersed polyurethane, 10 to 25 parts by weight of the acrylic monomer, and 1 to 3 parts by weight of an initiator are added and stirred with respect to 100 parts by weight of the water-soluble acrylic polyurethane. A method for producing an eco-friendly hamburger wrapping paper using a nano clay-dispersed water-soluble acrylic polyurethane coating solution, characterized in that it is carried out by
The method of claim 1,
The step (d) of dispersing the clay treated with the organic agent in the water-soluble acrylic polyurethane is performed by dispersing 2-5% of the clay treated with the organic agent in 95-98 wt% of the water-soluble acrylic polyurethane, A method for manufacturing eco-friendly hamburger wrapping paper using nano clay-dispersed water-soluble acrylic polyurethane coating solution.
An eco-friendly hamburger wrapping paper using a nano clay-dispersed water-soluble acrylic polyurethane coating solution prepared according to the manufacturing method of any one of claims 1 to 2 and 5 to 7.
9. The method of claim 8,
Eco-friendly hamburger wrapping paper using nano clay-dispersed water-soluble acrylic polyurethane coating solution, characterized in that the coating layer consists of 1 to 3 layers.

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