KR20100137850A - Waterproofing/oilproofing agent and paper for food container having waterproofing/oilproofing agent and process thereof - Google Patents

Abstract

PURPOSE: Environment friendly waterproof/greaseproof agents which are an alternative of polyethylene, and a manufacturing method thereof are provided to assign waterproof/greaseproof functions on a paper board using natural pulps. CONSTITUTION: Initial solution is put into a 4 liter reactor. The initial solution is stirred. The temperature of the reactor increases. Monomer tank mixing solution and initiator tank mixing solution are put into the reactor at once. The temperature is maintained so that the temperature of the reactor is not hotter than 100 degrees. Reaction is made for 120 minutes. Seed latex is obtained by the reaction.

Description

Eco-friendly water- and oil-resistant alternative to polyethylene, and food packaging paper using the same and manufacturing method thereof

The present invention is a method for producing a food packaging paper having a heat-adhesive function by coating with an on-machine coating method in a paper machine of a paper mill by applying a polyethylene replacement waterproofing / oil resistant agent to provide an eco-friendly food packaging paper and the packaging paper It is about.

Paper used for packaging goods is called wrapping paper. There is only good toughness and water resistance suitable for protecting the contents, and good printability as well.

The former must have some degree of water resistance with strength, while the latter must have some beauty and printability in addition to the former properties. The former is a kraft paper made mainly from unbleached chemical pulp (UKP), and is used for packaging bags such as cement sugar fertilizer starch. Typical of the latter is a polarized paper, generally called a rolled paper, which is a paper made by using a yankee machine so that only one side is glossy, and is mainly used for packing light items.

In particular, food packaging paper should have excellent water and oil resistance. In the meantime, if the paper packaging is produced and supplied by a paper maker, the post-processing company carries out a polyethylene coating with water / oil resistance and heat adhesion, and if necessary, flexo printing or gravure printing, and then post-processing for molding. have. PE coated food packaging containers that are currently commercialized are not recycled and are incinerated after sorting, which is negative to the global trend that emphasizes the importance of the environment.

Therefore, there is an urgent need for an eco-friendly water repellent agent that can replace polyethylene in related industries. In addition, this eco-friendly water / oil agent can be coated by on-machine coating in a paper mill to provide a water-resistant function for food packaging containers that require not only water / oil resistance but also post-processing. As a result, it is possible to reduce the incidental cost due to polyethylene coating of post-processing companies, and this eco-friendly waterproofing / oilproofing coated paper can be recycled as a raw material in the paper mill, which can make a positive contribution to the global trend of eco-friendliness. . However, in order to coat polyethylene replacement water / oil agent in on-machine coating method in the paper mill Due to contamination of the process and roll blocking (= sticking between the sheets of the winding rolls), it was not easy to use.

Therefore, the present inventors solved the problem of contamination and roll blocking in the process of on-machine coating at a paper mill, which is used for food packaging containers requiring post-processing of molding, and latex water / This paper describes how to produce eco-friendly food packaging paper with oil-resistant agent and its characteristics.

The present invention relates to post-processing that provides eco-friendly water / oil resistant agent, imparts water / oil resistance to cardboard using natural pulp, and requires molding, and is capable of thermal bonding and process contamination and roll blocking in a paper mill. On-machine coating is possible without a state, and the purpose of the food packaging paper that can be recycled as a raw material in the paper mill.

The present invention relates to a latex water / oil resistant agent comprising a core-shell structured copolymer latex having a different glass transition temperature and a method for producing the same.

The present invention is a step of coating a pre-coating layer of the core-shell structured copolymer latex water- / oil-resistant on the upper surface of the base paper; Drying the precoat layer; 3 steps of coating the back coating layer on the lower surface of the base paper; 4 steps of drying the back coating layer; Coating a top-coating layer of core-shell structured copolymerized latex water- / oil-resistant on the pre-coating layer of the upper surface of the base paper; And 6 step of drying the top coating layer; relates to a food packaging paper manufacturing method comprising a.

The present invention is in contact with a pre-coating layer made of a core-shell structured copolymerized latex water- / oil-resistant starch composite composition on the upper surface of the base paper, and made of a core-shell structured copolymerized latex water- / oil-resistant antiblocking agent composite composition on the precoat layer. The top coating layer is in contact with, and the bottom layer of the base paper relates to a food packaging paper in contact with the back coating layer made of a starch composition.

The latex water / oil agent of the present invention is excellent in water resistance and blocking properties.

This water / oil resistant food packaging paper can be recycled as a support material, which is environmentally friendly, applicable to beverages and food packaging containers requiring water / oil resistance, and heat-sealed when used for food packaging containers requiring molding by post-processing. It is possible to apply the on-machine coating without any process contamination and roll blocking at the paper mill, which can reduce the cost due to the existing post-processed polyethylene coating. It is suitable and meets domestic food packaging quality standards.

The present invention relates to a latex water / oil resistant agent comprising a core-shell structured copolymer latex, wherein the copolymer latex is characterized in that the glass transition temperatures of the core part and the shell part are different from each other.

Preferably, the core portion of the core portion is a glass transition temperature of-10 ℃ ~ 10 ℃, the shell portion is a latex water / oil resistant agent, characterized in that the glass transition temperature is 20 ℃ ~ 50 ℃, the copolymer latex The average particle diameter of is a latex water / oil resistant agent, characterized in that 800 ~ 2000 kPa.

More preferably, the present invention is for the latex water- / oil-resistant agent, characterized in that the copolymer latex is a water-soluble emulsion having a solid content of 40 to 60% by weight.

In addition, the present invention comprises the steps of preparing a seed latex by adding a molecular weight regulator and an initiator to a mixture of a soft monomer, a hard monomer and a carboxylic acid monomer; Mixing the seed latex with a soft monomer, a hard monomer and a carboxylic acid monomer mixture and adding a molecular weight regulator and an initiator to prepare a core portion latex; And adding a soft monomer, a hard monomer, and a carboxylic acid monomer mixture to the core portion latex, and adding a molecular weight regulator and an initiator to prepare a core-shell structured copolymer latex. It is about.

Preferably, the soft monomer is one or a mixture of two or more selected from butadiene, butyl acrylate, 2-ethylhexyl acrylate, ethyl acrylate, methyl acrylate, 2-hydroxyethyl acrylate and ethylene. The hard monomer is one or a mixture of two or more selected from styrene, acrylonitrile, methyl methacrylate, ethyl methacrylate, butyl methacrylate, vinyl acetate and methacrylonitrile. To a method for preparing a core-shell structured copolymer latex.

In addition, the present invention relates to a method for producing a core-shell structured copolymer latex, characterized in that the carboxylic acid monomer is one or a mixture of two or more selected from acrylic acid, itaconic acid, fumaric acid and methylmethacrylic acid.

More preferably, the molecular weight modifier is one or a mixture of two selected from tertiary-dodecyl mercaptan and alpha-methylstyrene, and the initiator is a persulfate. The present invention relates to a method for preparing a core-shell structured copolymer latex, characterized in that one or a mixture of two or more selected from potassium persulphate, sodium persulphate, and ammonium persulphate.

Through the present invention, when coating the industrial paper base, the existing eco-friendly water-resistant / oil-resistant alternative to starch and epomin instead of polyethylene is coated on the upper layer, and the starch and the printing enhancer are coated on the lower layer to reduce the cost and eco-friendly by shortening the process. We want to produce a product.

Food packaging paper should have good water and oil resistance. In the meantime, if the paper packaging is produced and supplied by a paper maker, the post-processing company carries out a polyethylene coating with water / oil resistance and heat adhesion, and if necessary, flexo printing or gravure printing, and then post-processing for molding. have. Currently commercially available polyethylene coated food packaging containers are not recycled and are incinerated after incineration, which is negative for the global trend of emphasizing the importance of the environment.

On the other hand, the core-shell structured copolymer latex water / oil agent proposed in the present invention can be recovered and reprocessed so that it can be coated in an environmentally friendly, on-machine coating method. In other words, if the paper mill is coated with the on-machine coating method and has the heat-sealing function necessary for food packaging containers requiring molding after processing as well as water / oil resistance, the polyethylene coating process can be omitted. As a result, it is possible to reduce the incidental cost, and this eco-friendly water- and oil-coated paper can be recycled as a raw material in the paper mill, which can make a positive contribution to the global trend of eco-friendliness.

However, in order to coat the existing polyethylene replacement water / oil agent by on-machine coating method in the paper mill, it was not easy to use due to the contamination problem of the process and roll blocking (= Roll Blocking, sticking the paper sheet of the take-up roll). The coating composition incorporating the core-shell structured copolymer latex water / oil agent proposed by the present invention has a problem of contamination of the process and rolls due to the difference in the glass transition temperature (Tg) between the core of the latex particle structure and the shell. There is no blocking problem.

Typical latexes are in homogeneous form with a constant glass transition temperature. Latex corresponding to the soft region of the glass transition temperature range of -10 ~ 10 ℃ is excellent in water resistance, but the blocking is poor, and in the hard region of the glass transition temperature range of 20 ~ 50 ℃ excellent blocking but water resistance. That is, since the trade-off (Trade Off) form in the latex properties, it is difficult to apply a product that satisfies the water resistance and blocking properties as a general latex in the market.

However, the core-shell structured copolymerized latex water- / oil-resistant agent of the present invention corresponds to the core of the latex particles, but the inside is butadiene, butyl acrylate, 2-ethylhexyl acrylate, ethyl for water resistance and heat sealing. A low monomer glass transition temperature such as acrylate was used abundantly to have a soft glass transition temperature. The outer shell corresponding to the shell of the particles has a high glass transition temperature such as styrene, acrylonitrile, methyl methacrylate, and the like to have a glass transition temperature in the hard region. Therefore, the present invention is structured with a core-shell type latex having two glass transition temperatures (Tg) of satisfying both water resistance and blocking resistance to be obtained (see FIG. 5).

In addition, the molecular weight of the latex is formed large in order to suppress sticky properties caused by the material having a low molecular weight. By optimizing the molecular weight regulator and the crosslinking agent, the molecular structure of the latex is branched and crosslinked to increase the molecular weight of the latex and further enhance blocking properties. Since molecular weight affects heat sealing important in food packaging containers, it is necessary to increase the molecular weight as much as possible. The higher the molecular weight, the better the thermal adhesion. Therefore, even though the outside, which is a shell of the particles of the latex of the present invention, has a glass transition temperature in the hard region, which is disadvantageous for thermal bonding, the thermal bonding characteristics can be excellently exhibited by the molecular weight adjusting technique by optimizing the use of a molecular weight regulator and an initiator.

In general, oligomers having a low molecular weight (Olygomer) is unstable to increase the stickiness phenomenon and cause odor is not suitable for use in food containers. Therefore, in order to produce the core-shell structured copolymerized latex water / oil agent, the uniformity of the particles is ensured by seed polymerization and styrene (SM), butadiene (BD), butyl acrylate and methyl methacrylate. (MMA), 2-hydroxyethyl acrylate (2-HEA), 2-ethylhexyl acrylate (2-EHA), ethyl acrylate (EA), atrylonitrile (AN), vinyl acetate (VAC), Acrylic acid (AA), itaconic acid (IA), fumaric acid (FA), methacrylic acid (MAA) are used as monomer raw materials, and the distribution of the raw materials is optimized inside the particles as well as molecular weight regulators such as mercaptan or alpha methyl styrene. It is preferable to use an appropriate amount.

More preferred monomer compositions for producing the core-shell structured copolymerized latex water / oil agent are as follows.

10 to 60 parts by weight of styrene (SM), 0.1 to 20 parts by weight of butadiene (BD), 10 to 60 parts by weight of butyl acrylate (BA), 5 to 30 parts by weight of methyl methacrylate (MMA), 2-hydroxyethyl 0.1 to 10 parts by weight of acrylate (2-HEA), 5 to 30 parts by weight of 2-ethylhexyl acrylate (2-EHA), 0.1 to 30 parts by weight of ethyl acrylate (EA), attrilonitrile (AN) 1 to 20 parts by weight, vinyl acetate (VAC) 0.1 to 10 parts by weight, acrylic acid (AA) 0.1 to 7 parts by weight, itaconic acid (IA) 0.1 to 7 parts by weight, and fumaric acid (FA) 0.1 to 7 parts by weight as a monomer raw material .

 0.1 to 2 parts by weight of potassium persulfate (KPS), 0.1 to 2 parts by weight of sodium persulfate (SPS), 0.1 to 2 parts by weight of ammonium persulfate (APS) as an initiator, and 0.1 to 2 parts of sodium dodecylbenzenesulfonate (SDBS) 4 parts by weight are used as emulsifier.

50 ± 10% solids obtained through chemical and physical stripping to remove residual monomers by reacting for 3 to 12 hours at a temperature of 60 to 90 ℃ by seed polymerization or in-situ polymerization The core-shell structured copolymer latex having a particle diameter of 800 to 2000 mm 3 and glass transition temperature (Tg) of -10 to 50 ° C is polymerized.

Polymerized core-shell structured copolymer latex is water-soluble emulsion, which has affinity with water and can be directly applied without the need for a separate dissolution device when applied to the process. Because it removes, there is an advantage that no toxic gas is generated during operation. On the other hand, polyethylene not only requires a separate high temperature dissolution equipment and injection apparatus for use, but also has a problem that harmful gases are generated when melting at high temperatures.

Table 1 summarizes the ease of use in the papermaking process.

Item Paper process requirements Copolymerized latex Polyethylene Coating solution Slurry phase Aqueous milk emulsion Solid Bead Plastic Coating solution preparation Dispersion system mixed in water Can be mixed directly with water Insoluble in water / melting equipment required On-machine coating On Machine Coater possible Impossible recycle Fixture reuse possible Impossible Drying method Hot air dryer Hot air Cooling

As shown in Table 1, it can be seen that the copolymer latex is excellent in all respects. That is, it is preferable to use the core-shell structured copolymer latex proposed in the present invention.

The present invention is the first step of coating a pre-coating layer made of a composition comprising 50 to 100 parts by weight of the core-shell structured copolymer latex water / oil agent, 10 to 50 parts by weight of inorganic material and 10 to 30 parts by weight of starch on the upper surface of the base paper ; 2 steps of drying the pre-coating layer at 100 ~ 200 ℃; 3 to coat the back coating layer made of a composition comprising 70 to 100 parts by weight of starch, 20 to 100 parts by weight of inorganic material, 10 to 40 parts by weight of core-shell structured copolymer latex and 2 to 10 parts of blocking agent on the lower layer of the base paper. step; 4 steps of drying the back coating layer at 100 ~ 200 ℃; Coating a top coating layer made of a composition comprising 50 to 100 parts by weight of core-shell structured copolymer latex water / oil resistant agent, 10 to 50 parts by weight of inorganic material, and 2 to 10 parts by weight of antiblocking agent on the preliminary layer of the upper surface of the base paper. 5 steps; And six steps of drying the top coating layer at 100 to 200 ° C.

Industrial paper base consists of five layers of natural pulp. First, the imported natural pulp is diluted with water, and then mechanically processed, such as a refining millstone, to increase the strength of the paper. Subsidiary materials such as fillers, retention agents, size agents and the like are added to the mechanically treated pulp. The pulp, which has undergone this process, is put into a paper-making process called paper machine, through which a base paper is formed through dehydration, compression, and drying. Starch formed through the papermaking process is made of starch and epamine coating in the coating machine.

A pre-layer, which is a core-shell structured copolymer latex water- / oil-resistant agent, is coated on the upper surface of the base paper, and the pre-layer is dried through a hot air dryer. Thereafter, the starch layer is coated on the lower layer surface of the base paper, and the starch layer is dried through the hot air dryer. The top layer which is a core-shell structured copolymer latex water- / oil-resistant is coated on the preliminary layer of the upper surface of the base paper. The coated base paper is dried through a cylinder drier, through a hard nip calender process and a soft nip calender process, and finally subjected to a reel process (see FIGS. 3 and 4).

The present invention introduces the core-shell structured copolymerized latex waterproofing / oilproofing agent and limits the composition ratio when applied to a method for manufacturing a food packaging container, on-machine coating in the paper factory without process contamination and roll blocking This is possible and from this it is possible to reduce the costs due to conventional post-processed polyethylene coatings.

The present invention is in contact with a pre-coating layer made of a core-shell structured copolymerized latex water- / oil-resistant starch composite composition on the upper surface of the base paper, and made of a core-shell structured copolymerized latex water- / oil-resistant antiblocking agent composite composition on the precoat layer. The top coating layer is in contact with, and the bottom layer of the base paper relates to a food packaging paper that is in contact with the back coating layer made of a starch composition.

Preferably the present invention is the core-shell structured copolymerized latex water- / oil-resistant starch composite composition is a pre-coating layer 50-100 parts by weight of the core-shell structured copolymerized latex water / oil agent, 10 to 50 parts by weight of inorganic matters and The present invention relates to a food packaging paper comprising a composition containing 10 to 30 parts by weight of starch, and the coating amount of the precoat layer is about 2 to 10 g / m 2.

Preferably, the present invention is the core-shell structured copolymer latex water resistant / oil resistant antiblocking agent composite composition top coating layer is a core-shell structured copolymer latex water resistant / oil resistant agent 50 ~ 100 parts by weight, inorganic material 10 ~ 50 parts by weight , For a food packaging paper comprising a composition comprising 2 to 10 parts by weight of an antiblocking agent, wherein the coating amount of the top coating layer is about 2 to 10 g / m 2.

Preferably, the present invention is a back coating layer made of the starch composition comprises 70 to 100 parts by weight of starch, 20 to 100 parts by weight of inorganic matter, 10 to 40 parts by weight of the core-shell structured copolymer latex and 2 to 10 parts by weight of antiblocking agent. It is for a food packaging paper comprising a composition, the coating amount of the back coating layer is for a food packaging paper, characterized in that 0.2 ~ 10 g / ㎡.

In addition, the present invention relates to a food packaging paper, characterized in that the base paper is applied to the emulsion size agent.

Food packaging paper should have good water and oil resistance. In the meantime, if the paper packaging is produced and supplied by a paper maker, the post-processing company carries out a polyethylene coating with water / oil resistance and heat adhesion, and if necessary, flexo printing or gravure printing, and then post-processing for molding. have. Currently commercially available polyethylene coated food packaging containers are not recycled and are incinerated after incineration, which is negative for the global trend of emphasizing the importance of the environment.

On the other hand, the core-shell structured copolymer latex water / oil agent proposed in the present invention can be recovered and reprocessed so that it can be coated in an environmentally friendly, on-machine coating method. In other words, if the paper mill is coated with an on-machine coating method and has a heat-sealing function necessary for food packaging containers requiring molding after processing as well as water / oil resistance, the polyethylene coating process can be omitted. As a result, it is possible to reduce the incidental cost, and this eco-friendly water- and oil-coated paper can be recycled as a raw material in the paper mill, which can make a positive contribution to the global trend of eco-friendliness.

However, in order to coat the existing polyethylene replacement water / oil agent by on-machine coating method in the paper mill, it was not easy to use due to the contamination problem of the process and roll blocking (= Roll Blocking, sticking the paper sheet of the take-up roll). The coating composition incorporating the latex water- / oil-proof agent proposed in the present invention has a high affinity with water because it is a water-soluble emulsion, and the outside corresponding to the shell of the core-shell structured copolymer latex particles has a hard zone glass transition temperature. The use of monomers is advantageous for blocking, thus eliminating the problem of process contamination and roll blocking. That is, since the latex has a core-shell structure and simultaneously holds the soft zone and the hard zone glass transition temperature (Tg), the latex has excellent thermal adhesiveness, blocking resistance, and water resistance, thereby imparting barrier properties to water and oil resistance. It is used to manufacture and use styrene butadiene latex-based, acrylic latex-based, styrene acrylic latex-based, styrene butadiene acrylic latex-based products.

The starch is used to improve heat adhesion and water resistance of food packaging paper, and starch oxide is used.

The inorganic material is used to smoothly cover the rough surface of the food packaging paper and improve printability, and calcium carbonate, clay, titanium dioxide, and the like are used.

The blocking agent serves to prevent blocking by imparting releasability on the surface of the sticky adhesive material, and a wax emulsion, polyethylene wax emulsion, polypropylene wax emulsion, silicone emulsion, calcium stearate, and the like are used.

Food packaging paper can be recycled as a support material, which is environmentally friendly, applicable to beverages and food packaging containers requiring water / oil resistance, and can be heat-sealed when used in food packaging containers requiring molding by post processing. On-machine coating is possible in the paper mill without process contamination and roll blocking, which can reduce the cost of conventional post-processed polyethylene coatings, and is suitable for packaging in which beverages and foods directly reach through surface treatment of products. Meets packaging quality standards

The present invention is to produce a food packaging paper by applying a polyethylene replacement water / oil resistant agent in the papermaking process. In addition, heat-sealing properties are imparted to food packaging paper to satisfy a variety of packaging processes. Thermal bonding properties are determined by the necessity of the packaging process. In the case of oil resistance, types can be classified according to oil oil needs. The use of this food packaging container is applicable to all food packaging containers requiring water resistance and oil resistance, such as paper cups, cup noodles and chicken boxes.

The content of the present invention will be described in more detail with reference to preferred embodiments to help more clearly understand the present invention. However, these examples are only presented to understand the content of the present invention, the scope of the present invention is not limited to these examples.

Example  1. Placement ( Batch ) Monomer  Input reaction seed latex production

The initial aqueous solution (Initial Solution) was added to a 4 liter reactor and stirred at 240 rpm for 20 minutes based on the mixing ratio of raw materials as shown in Table 2 below. The reactor temperature was raised above 70 ° C. and maintained for 30 minutes. Thereafter, 100% of the prepared monomer tank mixed solution and the initiator tank mixed solution of the monomers and initiators of the configuration shown in Table 2 were added to the reactor at one time. The reaction proceeded for 120 minutes while maintaining the reactor temperature not to exceed 100 ℃ to obtain a seed latex. The prepared seed latex was 35% solids, pH 4, and particle diameters of 350 and 450 mm 3 according to Table 2 below.

Seed latex raw material division Raw material Example 1-1 Example 1-2 Example 1-3
Initial aqueous solution pure 150 150 150 Ethylenediaminetetraacetic acid (EDTA) 0.5 0.5 0.5 Sodium Dodecylbenzene Sulfate (SDBS) 10 10 10 Monomer Butadiene (BD) 10 10 Butyl acrylate (BA) 5 5 2-ethylhexyl acrylate (2-EHA) 5 10 Ethyl acrylate (EA) 10 Styrene (SM) 85 80 43 Methyl methacrylate (MMA) 5 20 Acrylonitrile (AN) 2 10 Acrylic acid (AA) 3 3 One Itaconic acid (IA) One 0.5 Fumaric acid (FA) One 0.5 Initiator Potassium Persulfate (KPS) 2 1.5 2 Ammonium Persulfate (APS) 0.5 pure 30 30 30 Sodium Dodecylbenzene Sulfate (SDBS) 0.5 0.5 0.5 Molecular Weight
Regulator Talentdodecyl Mercantane (TDDM) 0.25 0.2 Alphamethylstyrene (α-MSD) 0.05 Response time (minutes) 120 120 120 Properties Solid content (%) 35 35 35 pH 4 4 4 Particle diameter 350 350 450

Example  2. In-situ ( In Situ ) Monomer  Input reaction seed latex production

0.3 parts by weight of ethylenediaminetetraacetic acid (EDTA) and 10 parts by weight of sodium dodecylbenzene sulfate (SDBA) were added to 150 parts by weight of water in a 4 L high-pressure reactor, followed by stirring at 240 RPM. The reactor temperature was raised to 80 ° C. and maintained for 30 minutes.

30% of the mixed solution of the monomer and the molecular weight modifier having the configuration shown in Table 3 were temporarily added to the reactor, and then 30% of the mixed solution of the prepared initiator tank was added at a time and the reactor temperature was maintained at 80 ° C. using a cooling system. The reaction was carried out within 1 hour. After 1 hour, the remaining monomer and the initiator tank mixture were reacted at 80 ° C. while using a fixed metering pump for 120 minutes. The seed latex produced was 35% solids, pH 4, particle size 300 and 350 mm 3.

Seed latex raw material division Raw material Example 2-1 Example 2-2 Example 2-3 Step 1/2
(ratio) Stage 1 30 30 30 Step 2 70 70 70 Sum 100 100 100 Monomer Butadiene (BD) 10 10 Butyl acrylate (BA) 5 5 2-ethylhexyl acrylate (2-EHA) 5 10 Ethyl acrylate (EA) 10 Styrene (SM) 85 80 43 Methyl methacrylate (MMA) 5 20 Acrylonitrile (AN) 2 10 Acrylic acid (AA) 3 3 One Itaconic acid (IA) One 0.5 Methacrylic acid (MAA) 0.5 0.3 Fumaric acid (FA) 0.5 0.2 Initiator Potassium Persulfate (KPS) 2 1.5 2 Ammonium Persulfate (APS) 0.5 Sodium Persulfate (SPS) pure 30 30 30 Sodium Dodecylbenzene Sulfate (SDBS) 0.5 0.5 0.5 Molecular Weight
Regulator Talentdodecyl Mercantane (TDDM) 0.25 0.2 Alphamethylstyrene (α-MSD) 0.05 Response time (minutes) 120 120 120 Properties Solid content (%) 35 35 35 pH 4 4 4 Particle diameter 300 350 300

Example  3. Core-shell structure copolymerized latex manufacture

4 parts by weight of 4 parts by weight of the latex prepared in Examples 1 and 2, 0.3 parts by weight of ethylenediaminetetraacetic acid (EDTA) and 0.3 parts by weight of surfactant sodium dodecylbenzene sulfate (SDBA) And stirred at 240 RPM until the reactor temperature is 80 ℃. Thereafter, nitrogen was added to remove oxygen present in the reactor, and a monomer mixing tank and an initiator mixing tank of the monomer and the molecular weight modifier mixture were prepared and prepared in the ratios of Table 4, respectively.

The monomer mixing tank was connected to a metering pump connected to the reactor. An initiator mixing tank was also connected to the metering pump connected to the reactor.

Component ratio of core-shell structured copolymer latex Unit: parts by weight Latex Example Example 3-1 Example 3-2 Example 3-3 Example 3-4 Example 3-5 Example 3-6 Used seed latex Example 1-1 Example 1-2 Example 1-3 Example 2-1 Example 2-2 Example 2-3 core Monomer (%) 40 40 40 40 40 40 Response time (minutes) 240 240 240 240 240 240 Shell Monomer (%) 60 60 60 60 60 60 Response time (minutes) 240 240 240 240 240 240 Monomer Butadiene (BD) 20 20 Butyl acrylate (BA) 5 15 15 5 15 15 2-ethylhexyl acrylate (2-EHA) 5 15 10 5 15 10 Ethyl acrylate (EA) 5 10 5 5 10 5 Styrene (SM) 54 53 52 54 53 52 Methyl methacrylate (MMA) 5 10 5 10 Acrylonitrile (AN) 3 5 5 3 5 5 Acrylic acid (AA) 1.5 1.5 2 1.5 1.5 2 Itaconic acid (IA) One One One One Methacrylic acid (MAA) 0.5 0.5 0.5 0.5 Fumaric acid (FA) 0.5 0.5 Initiator Potassium Persulfate (KPS) 2 1.5 1.5 2 1.5 1.5 Ammonium Persulfate (APS) 0.5 0.5 Sodium Persulfate (SPS) 0.5 0.5 pure 30 30 30 30 30 30 Sodium Dodecylbenzene Sulfate (SDBS) 0.5 0.5 0.5 0.5 0.5 0.5 Molecular Weight
Regulator Talentdodecyl Mercantane (TDDM) 0.25 0.2 0.1 0.25 0.2 0.1 Alphamethylstyrene (α-MSD) 0.05 0.05 Properties Solid content (%) 51 51 51 51 51 51 pH 8 8 8 8 8 8 Particle diameter 1200 1250 1150 1200 1250 1150

After maintaining the reactor temperature at 80 ° C. for 30 minutes, 40% of the monomer mixing tank preparation solution and 40% of the initiator mixing tank preparation solution were introduced into the reactor at a constant input amount for 240 minutes using a metering pump to prepare a core latex part. After 5 minutes, the remaining 60% of the monomer mixture tank preparation liquid and the remaining 60% of the initiator mixing tank preparation liquid were introduced into the reactor at a constant dose using a respective metering pump for 240 minutes, and the cell-part latex was copolymerized on the surface of the core latex. A core-shell structured copolymer latex was prepared.

Example  4. Latex Waterproof / Oil-resistant  Produce

After completion of the final reaction of Example 3, the reaction was further proceeded for 120 minutes to first remove the unreacted monomer, and 0.005 parts by weight of sodium hyposulfite (SD), tertiary butylhydrogen peroxide (T-BHP) 0.005 parts by weight was added to the reactor to remove the second unreacted monomer.

The prepared latex was put into a high pressure stripper refining tank and stirred at a speed of 240 rpm while hot steam was injected from the lower part of the refining tank and 0.001 parts by weight of mineral oil-based antifoaming agent or silicon-based antifoaming agent was operated and a vacuum pump was operated to unreact in the refining tank. The monomer was carried out until the styrene standard was 50 ppm or less, and if the residual styrene was below the standard value, 1000 ppm of the prepared preservative was added to complete the latex production.

Core-shell structured water-soluble emulsion copolymerized latex prepared is core-shell structured water-soluble emulsion copolymer latex has a solid content of 51%, PH 8, particle diameter of 1150 ~ 2000Å, glass transition temperature -10 ℃ ~ + 50 ℃.

Example  5. Manufacture of food packaging paper

1) Mixing and preparing a coating agent including 50 parts by weight of the latex water / oil repellent agent of Example 4, 30 parts by weight of starch liquor mixed with calcium carbonate and clay in the on-machine coater of the paper machine Using a rod or a blade, the preliminary layer was uniformly coated (coating amount 10 g / m 2) in the machine direction and the width direction, and dried.

2) Subsequently, 60 parts by weight of starch oxide, 20 parts by weight of an inorganic substance and latex (20 parts by weight of a printing enhancer) are mixed together on the lower layer of the precoated base paper, and uniformly coated in the machine direction and the width direction using a blade. (Coating amount 5 g / m 2) and dried.

3) A coating agent including 50 parts by weight of latex water / oil agent, 30 parts by weight of inorganic material mixed with calcium carbonate and clay, 10 parts by weight of starch solution, and 10 parts by weight of antiblocking agent are mixed on the upper surface of the precoated layer 1). The top layer was uniformly coated in the machine direction and the width direction using a blade (coated amount of 10 g / m 2), and dried.

According to the above process, a food packaging paper was prepared.

Comparative example  1. Polyethylene food packaging container

A disposable paper cup for a beverage using the existing polyethylene was purchased. The existing paper cup is a product of Hyundai Clean Corporation, which is a paper cup for vending machine that has received the sanitary license No. 36. The paper cup is molded and manufactured by using polyethylene coated on non-fluorescent natural pulp. The standard size is 184 ml disposable paper cup. to be.

Test Example . Measurement of physical properties such as water resistance

The physical properties of Example 5 prepared by using the latex water / oil resistant agent prepared using the latex of Comparative Example 1 and Example 3 are shown in Table 5 below.

Water resistance was measured in 3% surfactant, 25% alcohol and 20 ml of high-temperature coffee to prepare food packaging papers of Examples and Comparative Examples, and the water resistance was measured by a Cobb size measurement method.

Oil resistance is shown in Table 5 using the T559I-02 KIT method, the oil resistance evaluation criteria of the Technical Association of the Pulp and Paper Industry (TAPPI).

Heat adhesiveness is measured by measuring cup formation by normal molding machine operation in the range of 200 ℃ or more, which is the general heat adhesive temperature condition of cup forming operation, using cup forming machine which uses food paper of Examples and Comparative Examples for paper cup production. The range is shown in Table 5 below.

Blocking resistance is shown in Table 5 by installing a hydraulic press in a thermo-hygrostat and measuring the test conditions by a five-point method under a temperature of 50 ° C., a humidity of 55% and a press pressure of 35 kgf / cm 2.

Latex Example Comparative Example 1 Example
3-1 Example
3-2 Example
3-3 Example
3-4 Example
3-5 Example
3-6 Water resistance
(Cobb size:
g / ㎡ / 1 minute) 3% surfactant 0.52 0.28 0.26 0.27 0.23 0.25 0.26 25% alcohol 0.47 0.38 0.35 0.37 0.35 0.35 0.37 coffee 1.50 1.55 1.53 1.51 1.50 1.50 1.51 Oil resistance
(Kit examination / TAPPI T559 T-02) 12 12 12 12 12 12 12 Thermal adhesion
(Paper Cup Molding Machine Adhesive Temperature, ℃) More than 200 More than 200 More than 200 More than 200 More than 200 More than 200 More than 200 Blocking resistance
(Press crimping test / five points method) 4.7 4.5 4.5 4.5 4.5 4.5 4.5

The harmlessness was tested by the Korea Institute for Living Environment Testing, and the results of the dissolution test, which is a harmlessness tester, are shown in Table 6 below.

Harmless test results of Example 5 Test Items unit Standard standard Test result Material testing Lead (Pb) mg / kg
100 or less
Not detected (detection limit 10) Cadmium (Cd) Not detected (detection limit 5)
Dissolution test
Heavy metals (Pb)
mg / l
1.0 or less 1.0 or less KMnO ₄ below 10 One Evaporation residue (4% acetic acid) 30 or less 10

Food Code Article 7. Standards and standards for equipment, containers and packaging

In the case of Comparative Example 1, the water resistance was 0.52, 0.47 and 1.50 for each sample, whereas in Example 5, the water resistance was measured as 0.23 to 0.28, 0.35 to 0.38 and 1.50 to 1.55. For water resistance, a Cobb size gauge (35 mm size) was used, and each measurement value was placed on the basis of the measuring device of Comparative Examples 1 and 5, and the amount of 20 ml of each sample was placed in the measuring device for 1 minute. After placing, the moisture absorption of the paper was measured and converted into a value of g / m 2. The lower the measured value, the smaller the moisture absorption, indicating that the water resistance was good. As a result of the test, the water resistance was found to be equal to or higher than that of the comparative example.

Oil resistance is TAPPI's oil resistance evaluation criteria, there are 12 evaluation numbers from kit number 1 to 12, and the higher the number, the better oil resistance. The oil resistance test result was evaluated in the same manner as the result of the comparative example and the result of Example 12, it was found that the invention product is equivalent to the oil resistance of polyethylene products.

Food containers that need heat adhesiveness are glued using heat when they are molded by post-processing companies, such as paper cups. The general heat adhesion temperature of paper cup forming machines is 200-300 ℃. In the case of the embodiment it can be seen that the normal cup molding at a heat adhesion temperature of 200 ℃ or more, the heat adhesion is equivalent to the polyethylene product.

In the case of blocking resistance, the comparative example showed 4.7 points and the example 4.5 points in the 5-point evaluation.

Even in the case of no harm, the Food Environment Research Institute's' Food Environment Article 7. According to the dissolution test results of the standards and specifications of the equipment and container packaging according to Table 6, the product of Example 5 showed a good result as in Comparative Example 1.

Therefore, the present invention is recyclable and harmless, which is eco-friendly, and can be applied to food packaging containers requiring water / oil / heat adhesive properties. Thermal adhesiveness and blocking resistance are equivalent to those of conventional polyethylene coated products. It can be industrialized because it can be produced by machine coating method. In addition, it is suitable for packing foods directly through the surface treatment of products and meets domestic food packaging quality standards.

1 is a schematic of the base paper and the coating layer of the food packaging paper of the present invention.

Figure 2 is a schematic of the base and coating layer of the existing on-machine coating product, for comparison with the present invention.

3 is a process chart for the water / oil repellent coating process of the present invention.

4 is a schematic view of a facility of the water / oil repellent coating process of the present invention.

5 is a schematic of the structure of a core-shell structured copolymer latex.

Claims (19)

Latex water / oil repellents including core-shell structured copolymerized latex. The method of claim 1, The copolymer latex is latex water resistant / oil-resistant, characterized in that the glass transition temperature of the core portion and the shell portion are different from each other. The method of claim 2, The core portion of the copolymer latex has a glass transition temperature of-10 ℃ ~ 10 ℃, the shell portion of the latex water / oil resistant agent, characterized in that the glass transition temperature is 20 ℃ ~ 50 ℃. 4. The method according to any one of claims 1 to 3, Latex water- / oil-resistant agent, characterized in that the average particle diameter of the copolymerized latex is 800 ~ 2000 kPa. 4. The method according to any one of claims 1 to 3, The copolymer latex is a latex water- / oil-resistant agent, characterized in that the water-soluble emulsion of 40 to 60% by weight solids. Preparing a seed latex by adding a molecular weight regulator and an initiator to a mixture of a soft monomer, a hard monomer and a carboxylic acid monomer; Mixing the seed latex with a soft monomer, a hard monomer and a carboxylic acid monomer mixture and adding a molecular weight regulator and an initiator to prepare a core portion latex; And Adding a soft monomer, a hard monomer and a carboxylic acid monomer mixture to the core portion latex and adding a molecular weight regulator and an initiator to prepare a core-shell structured copolymer latex; A method of producing a latex water resistant / oil resistant agent comprising a. The method of claim 6, The soft monomer is one or more mixtures selected from butadiene, butyl acrylate, 2-ethylhexyl acrylate, ethyl acrylate, methyl acrylate, 2-hydroxyethyl acrylate and ethylene. Process for preparing shell structured copolymer latex. The method of claim 6, The hard monomer is a core-shell structuring, characterized in that one or two or more selected from styrene, acrylonitrile, methyl methacrylate, ethyl methacrylate, butyl methacrylate, vinyl acetate and methacrylonitrile. Of the prepared copolymerized latex. The method of claim 6, The carboxylic acid monomer is a method for producing a core-shell structured copolymer latex, characterized in that one or two or more selected from acrylic acid, itaconic acid, fumaric acid and methyl methacrylic acid. The method of claim 6, The molecular weight modifier is a method for producing a core-shell structured copolymer latex, characterized in that the mixture of one or two selected from tertiary-dodecyl methane and alpha methyl styrene. The method of claim 6, Wherein the initiator is one or a mixture of two or more selected from potassium persulfate, sodium persulfate and ammonium persulfate. 1 step of coating a pre-coating layer made of a composition comprising 50 to 100 parts by weight of the core-shell structured copolymer latex water / oil agent, 10 to 50 parts by weight and 10 to 30 parts by weight of starch on the upper surface of the base paper; 2 steps of drying the pre-coating layer at 100 ~ 200 ℃; 3 to coat the back coating layer made of a composition comprising 70 to 100 parts by weight of starch, 20 to 100 parts by weight of inorganic material, 10 to 40 parts by weight of core-shell structured copolymer latex and 2 to 10 parts of blocking agent on the lower layer of the base paper. step; 4 steps of drying the back coating layer at 100 ~ 200 ℃; Coating a top coating layer made of a composition comprising a core-shell structured copolymer latex water resistant / oil resistant agent 50 ~ 100 parts by weight, inorganic material 10 ~ 50 parts by weight, antiblocking agent 2 ~ 10 parts by weight in the preliminary layer of the upper surface of the base paper 5 steps; And 6 steps of drying the top coating layer at 100 ~ 200 ℃; Food packaging paper manufacturing method comprising a. A precoat layer made of a core-shell structured copolymer latex water resistant / oil starch composite composition is in contact with an upper surface of the base paper, and a top coating layer made of a core-shell structured copolymer latex water resistant / oil agent antiblocking agent composite composition is formed on the precoating layer. The food packaging paper is in contact with, the bottom layer of the base paper is in contact with the back coating layer made of a starch composition. The method of claim 13, The pre-coating layer composed of the core-shell structured copolymer latex water / oil starch composite composition may include 50 to 100 parts by weight of core-shell structured copolymer latex water / oil agent, 10 to 50 parts by weight of inorganic material, and 10 to 30 parts by weight of starch. Food packaging paper comprising a composition comprising. The method of claim 14, The food coating paper, characterized in that the coating amount of the pre-coat layer is 2 ~ 10 g / ㎡. The method of claim 13, The top coating layer is a food wrapping paper, characterized in that the core-shell structured copolymer latex water resistant to 50 to 100 parts by weight, consisting of 10 to 50 parts by weight of inorganic materials, 2 to 10 parts by weight of antiblocking agent. The method of claim 16, Food coating paper, characterized in that the coating amount of the top coating layer is 2 ~ 10 g / ㎡. The method of claim 13, The back coating layer is 70 to 100 parts by weight of starch, 20 to 100 parts by weight of inorganic material, core-shell structured copolymerization Food packaging paper comprising a composition comprising 10 to 40 parts by weight of latex and 2 to 10 parts by weight of an antiblocking agent. The method of claim 18, The coating amount of the back coating layer is food packaging paper, characterized in that 0.2 ~ 10 g / ㎡.

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