WO2020230962A1 - Method for manufacturing pulp molded product with excellent antimicrobial performance and pulp molded product manufactured thereby - Google Patents

Abstract

The present invention relates to a method for manufacturing a pulp molded product with excellent antimicrobial performance and gas adsorption capacity, and excellent strength, and a pulp molded product manufactured thereby, the method comprising the steps of: pulverizing natural minerals; preparing a suspension of the natural minerals and calcium carbonate, the suspension having excellent dispersibility; preparing a pulp suspension in which calcium carbonate is uniformly attached to the surface of pulp; and manufacturing a pulp molded product by molding using a mixed solution in which the suspension of the natural minerals and calcium carbonate and the pulp suspension are mixed.

Description

Method for producing a pulp molded body with excellent antibacterial performance and a pulp molded body manufactured thereby

The present invention relates to a method for producing a pulp molded article having excellent antibacterial performance and gas adsorption ability and excellent strength, and a pulp molded article produced thereby.

Recently, as consumers' interest in the food environment has increased, there has been a high interest in the safety and rationality of packaging for storage and distribution when purchasing food or agricultural products. Therefore, there has been a lot of development and growth in related packaging technology and packaging materials.

In particular, packaging technology and packaging materials maintain the freshness of foods (which may be referred to as "food") such as meat, fish, vegetables, fruits, and processed foods for a certain period of time, and prevent contamination from various harmful external environments. It has been developed in the direction of When food is stored, the freshness of the food decreases over time, and the spoilage situation of the food cannot be avoided due to the growth of mold and bacteria. In particular, due to the increase in single-person households and the development of eating out culture, there is an increasing number of cases where foods must be stored for a long period of time, and a large amount of foods are spoiled and discarded.

On the other hand, during long-term storage and transportation of fruits and vegetables, it adsorbs and removes ethylene gas and carbon dioxide gas generated by the respiration of fruits and vegetables, and maintains the freshness of fruits and vegetables by preventing or delaying decay by microorganisms and deodorizing by adsorption and removal of ammonia. In addition to the effect of prolonging the distribution and storage period, since the purchase value of fruit and vegetables products is increased and only the scent remains, it is possible to stimulate the purchase desire of consumers, thereby improving marketability.

However, polymer resins such as polyethylene (PE), polypropylene (PP), and polyester (PET) used as raw materials have various chemical substances added to satisfy the physical properties, so they are not only harmful to the environment, but also There is a concern of adversely affecting the human body due to elution, and environmental hormones are released during disposal. In addition, since it is a form that prevents moisture from leaving the food stored inside and inflow of external air, short-term freshness and spoilage can be prevented, but long-term spoilage and deterioration of food cannot be managed, and harmful substances such as residual pesticides are also in the packaging. There is a problem that remains and is passed on to consumers.

On the other hand, agricultural products such as fresh foods, fruits and vegetables are mainly packaged and distributed in cardboard boxes. The corrugated cardboard box serves to protect the appearance of the product, but since it does not have a function to maintain freshness in the long-term distribution process, fresh foods such as fruits and vegetables are deteriorated due to over-ripe, and the shelf life is shortened. Most fruits and vegetables ripen over time. At this time, ethylene gas, the ripening hormone of the plant, is generated, which accelerates ripening, causing rancidity.

To solve this problem, in Korean Patent Publication Nos.0788874 and 1155857, a coating agent containing zeolite and bentonite having moisture absorption and adsorption properties is applied to at least one side of a base paper (non-woven fabric or paper) to improve the freshness of food. It was intended to prevent vegetables and fruits from withering or deteriorating by providing sustainable packaging materials. However, the coating agent has low fluidity and very poor dispersibility, and problems such as clogging of the nozzle continue to occur during the manufacturing process.

In addition, the applicant of the present invention prepares a coating solution by mixing zeolite powder, diatomaceous earth powder, calcium carbonate powder, water and polylactic acid through Korean Patent Publication No.1768910, and uses the coating solution as a base paper (paper, textile). Or, a method of manufacturing a food packaging material coated on a nonwoven fabric) and dried has been proposed. However, the polylactic acid contained in the food packaging material has a high heat shrinkage rate and low heat resistance, so there is a concern that the packaging material may be deformed in summer, and the impact resistance is low, so that it is easily broken by external force.

In addition, as the use of recycled fibers increases in the manufacture of the pulp molded body, the physical properties of the pulp molded body rapidly deteriorate, so thick papermaking is performed to maintain a certain level of physical properties. As a result, as the weight of the packaging paper becomes heavier, the logistics cost increases accordingly. Therefore, there is an urgent need for lightweight, strong, and eco-friendly functional pulp molded articles.

In addition, even in the case of a precision machine such as a watch or a camera, damage to the product may be caused by harmful gases such as carbonic acid or ammonia generated from the inside of the packaging box. For this reason, there is a need to develop a wrapping paper that can protect the precision machine from the outside while adsorbing harmful gas to the precision machine.

The present invention was conceived to solve the above problems, and prevents the propagation of mold and bacteria in the distribution and sale of food, and prevents the problem of rapidly deteriorating freshness by ethylene gas generated in the cell respiration process of food. In order to solve this problem, a method for producing a pulp molded body that can not only adsorb and remove biological overripe substances such as ethylene gas, amine, ammonia, acetic acid, etc., but also reduce strength or breakage while being environmentally friendly, and the pulp produced thereby It is intended to provide a molded body.

In one embodiment of the present invention, for one or more natural minerals selected from the group consisting of zeolite, diatomaceous earth, illite, pozzolan, and mixtures thereof, pulverizing the particle size to 200 to 500 mesh; With respect to 100 parts by weight of the pulverized natural mineral, 10 to 30 parts by weight of calcium carbonate, 5 to 15 parts by weight of an acrylate-based copolymer, 1 to 5 parts by weight of a surfactant, and 500 to 1000 parts by weight of water are mixed to provide excellent dispersibility. Preparing a suspension of natural minerals and calcium carbonate; With respect to 100 parts by weight of at least one pulp selected from the group consisting of softwood pulp, hardwood pulp, old paper pulp, and mixtures thereof, water at a concentration of 1000 to 2000 parts by weight, calcium carbonate 5 to 25 parts by weight, 1 to 5% by weight After mixing and stirring 50 to 70 parts by weight of an aqueous calcium hydroxide solution and 0.1 to 2 parts by weight of citric acid, CO ₂ gas is injected to carbonate, and 5 to 15 parts by weight of a water-soluble polymer are further added while the carbonation is in progress. Preparing a pulp suspension evenly attached to the pulp surface; And using the natural mineral and calcium carbonate suspension, and a mixed solution of the pulp suspension in a weight ratio of 1: 5 to 10, the method for producing a pulp molded article comprising the step of forming a pulp molded article by molding to provide.

In the step of preparing a suspension of the natural mineral and calcium carbonate; The calcium carbonate has an average particle diameter of 100 to 700 nm, and the acrylate copolymer is an acrylate/acrylamide copolymer, an acrylate/acetoacetoxyethylmeth-acrylate copolymer and an acrylate/C10-C30 alkyl It is one or more acrylate-based copolymers selected from the group consisting of acrylate crosslinked polymers, and the surfactant may be a compound represented by Formula 1 below.

[Formula 1]

In Formula 1, R ₁ is an alkyl group having 5 to 20 carbon atoms, R ₂ is an alkyl group having 1 to 10 carbon atoms, and X is 1 to 40.

In the step of preparing the pulp suspension; The calcium carbonate has an average particle diameter of 1 to 100 nm, and the water-soluble polymer may be a mixture of polymethacrylic acid (PMAA) and water-soluble cellulose in a weight ratio of 2:1.

Another embodiment of the present invention provides a pulp molded article manufactured by the method for manufacturing a pulp molded article according to the exemplary embodiment of the present invention.

The method of manufacturing a pulp molded article according to an embodiment of the present invention has an effect of providing a pulp molded article having excellent antibacterial performance and gas adsorption ability and excellent strength.

More specifically, the pulp molded body according to an embodiment of the present invention exhibits strong antibacterial activity against microorganisms such as fungi, mold and yeast that cause deterioration and decay of contents such as fruits and vegetables to maintain freshness of contents such as fruits and vegetables for a long time. It has the effect of increasing product value.

In addition, it has excellent gas adsorption ability to adsorb and remove substances that cause overripe of fruits and vegetables such as ethylene gas, amine, ammonia, acetic acid, etc., solving the problem of rapidly deteriorating freshness due to ethylene gas generated in the cell respiration process of fresh food. It has a very suitable effect as a packaging material for fresh food and/or precision home appliances.

Further, by solving the problem that may cause damage to the product by harmful gases such as carbonic acid or ammonia in a very small amount generated from the inside of the packaging box, there is an effect very suitable as a packaging material for precision machinery such as watches and cameras.

In addition, the pulp molded article according to an embodiment of the present invention has a very excellent tensile strength effect.

1 shows a schematic image of a molding tank for manufacturing a pulp mold according to an embodiment of the present invention.

Figures 2 and 3 are images showing a comparison of the state of proliferation by inoculating a control piece and a pulp mold prepared according to an embodiment of the present invention, Figure 2 is pneumococcal, Figure 3 is 18 hours by inoculating Salmonella bacteria It is a proliferation.

Hereinafter, embodiments of the present invention will be described in detail. However, this is presented as an example, and the present invention is not limited thereby, and the present invention is only defined by the scope of the claims to be described later.

In one embodiment of the present invention, for one or more natural minerals selected from the group consisting of zeolite, diatomaceous earth, illite, pozzolan, and mixtures thereof, pulverizing the particle size to 200 to 500 mesh; With respect to 100 parts by weight of the pulverized natural mineral, 10 to 30 parts by weight of calcium carbonate, 5 to 15 parts by weight of an acrylate-based copolymer, 1 to 5 parts by weight of a surfactant, and 500 to 1000 parts by weight of water are mixed. Preparing a suspension of excellent natural minerals and calcium carbonate; With respect to 100 parts by weight of at least one pulp selected from the group consisting of softwood pulp, hardwood pulp, old paper pulp, and mixtures thereof, water at a concentration of 1000 to 2000 parts by weight, calcium carbonate 5 to 25 parts by weight, 1 to 5% by weight After mixing and stirring 50 to 70 parts by weight of an aqueous calcium hydroxide solution and 0.1 to 2 parts by weight of citric acid, CO ₂ gas is injected to carbonate, and 5 to 15 parts by weight of a water-soluble polymer are further added while the carbonation is in progress. Preparing a pulp suspension evenly attached to the pulp surface; And using the natural mineral and calcium carbonate suspension, and a mixed solution of the pulp suspension in a weight ratio of 1: 5 to 10, the method for producing a pulp molded article comprising the step of forming a pulp molded article by molding to provide.

Accordingly, the natural mineral and calcium carbonate having excellent antimicrobial performance and gas adsorption ability are very uniformly attached to the pulp and suspended evenly, and molded to thereby improve the antimicrobial performance and gas adsorption ability of the finally produced pulp molded body. Strength can also be greatly improved.

The natural mineral according to the present invention has excellent moisture absorption capacity and gas and heavy metal adsorption capacity, such as ethylene gas, amine, ammonia, acetic acid, etc. due to the structural characteristics of the numerous pore shapes made up of fine open cells and a large surface area of the inner space. It works. These natural minerals can be used together with those commonly used in the art.

The natural mineral is described in more detail as follows.

The zeolite is an aluminum silicate mineral of a porous crystal mainly containing an alkali metal or an alkaline earth metal, and the tetrahedron of (Si,Al)O ₄ forms a three-dimensional three-dimensional network skeleton structure by apical oxygen, and the central part Large pores are formed on the surface and contain water molecules and exchangeable cations. Water molecules are easily removed by heating at a relatively low temperature, but the skeleton of the zeolite structure does not change, so the zeolite after heating can absorb moisture in the air, and its chemical composition is W _y (Si,Al)(O ₂ ×nH ₂ O) W is mainly composed of sodium (Na) and calcium (Ca), and also contains potassium (K), magnesium (Mg), barium (Ba), and lithium (Li). In addition, zeolite has a pore diameter of a certain size, so it selectively passes and adsorbs molecules smaller than this, and selectively and strongly adsorbs unsaturated hydrocarbons or polar substances by the action of cations in the crystal structure. In addition, the cations can be easily exchanged with other cations, so that harmful substances can be removed, useful components are concentrated and recovered, and some of the cations are replaced with anions to have antibacterial properties, so that food quality and freshness can be maintained. do.

The diatomaceous earth is a rock or sediment formed by accumulating the remains of diatoms, which are single-celled organisms, mainly composed of silicon dioxide (SiO2), mostly amorphous silica, and some crystalline silica therein, Due to the complex structure and primary and secondary voids of the shell, the density is very low, and there are countless gaps in the diatom cell, so it can filter out impurity particles, and it has excellent properties of thermal insulation, fire resistance, chemical resistance, and water absorption.

The illite is a representative clay mineral, which has a large surface area and rich reactivity because it is fine, has a layered structure, has a void formed between layers, has plasticity in the state of containing moisture, and is sintered when heated. Have.

The pozzolan is a porous material, and there are natural pozzolans such as cement mixtures, soluble clay, silicate clay, weathered rocks of parliament, and artificial pozzolans such as fly-ash, and contain a lot of soluble silicic acid and are hydroponic. It does not have the property of hardening by easily compounding with lime in the presence of water, absorbing and adsorbing volatile organic compounds harmful to the human body such as formaldehyde, generating far-infrared rays and anions, removing odor, removing mold, removing odor, sterilizing, supplying oxygen, etc. Has the effect of.

More specifically, the above effect can be further improved by using a mixture of zeolite, diatomaceous earth, illite, and pozzolan in a weight ratio of 1:1 as the natural mineral. In addition, the natural mineral has an effect of further improving the above effect by pulverizing the particle size into 200 to 500 mesh, and improving strength by further improving miscibility and dispersibility with other components.

Then, based on 100 parts by weight of the pulverized natural mineral, 10 to 30 parts by weight of calcium carbonate, 5 to 15 parts by weight of an acrylate-based copolymer, 1 to 5 parts by weight of a surfactant, and 500 to 1000 parts by weight of water are mixed, A suspension of natural minerals and calcium carbonate with excellent acidity is prepared.

The calcium carbonate is not toxic to the human body, has antibacterial and disinfecting power against various harmful bacteria and microorganisms, and has high hydrophilicity and low oil absorption, as well as functions as extenders and reinforcing agents with excellent hardness, heat insulation, moisture absorption, and hiding properties. It has excellent homogeneity and is dispersed in water to form a suspension, and it serves to control the fluidity of the ceramic particles. In addition, by mixing and molding with the natural minerals and pulp, the surface of the pulp molded body is smoothed, and the strength of the pulp molded body is prevented from deteriorating due to moisture of the packaged object.

It is preferable that these calcium carbonates have a small particle size, but the smaller the particle size, the more the fibers do not spread even if they are inserted between the fibers of the pulp, so that the fibers can be formed in close contact with each other. Therefore, the strength of the pulp molded body is improved and cracking can be suppressed.

More specifically, the calcium carbonate present in the suspension of natural minerals and calcium carbonate having excellent dispersibility may have an average particle diameter of 100 to 700 nm, thereby further improving the above effect.

Since the acrylate-based copolymer has a network-type bond structure due to its three-dimensional crosslinking structure, it is present in a suspension of natural minerals and calcium carbonate, which significantly improves the dispersibility and persistence of dispersion of the natural mineral and calcium carbonate. It can have an effect. As a result, the natural mineral and calcium carbonate are distributed very evenly, so that the effects of antibacterial performance and gas adsorption capacity are remarkably improved. These acrylate-based copolymers are generally used in the art and are not particularly limited in their kind, but, for example, acrylate/acrylamide copolymer, acrylate/acetoacetoxyethylmeth-acrylate copolymer, and acrylic It is preferable to use at least one selected from the group consisting of rate/C10-C30 alkyl acrylate cross-polymer.

The surfactant allows the natural mineral and calcium carbonate to be easily distributed in the three-dimensional crosslinked structure of the acrylate-based copolymer, thereby further improving dispersibility and persistence of dispersion. As a result, the natural mineral and calcium carbonate are distributed very evenly, so that the effects of antibacterial performance and gas adsorption capacity are remarkably improved.

These surfactants can further improve the above-described effects by using a compound represented by the following formula (1).

[Formula 1]

In Formula 1, R ₁ is an alkyl group having 5 to 20 carbon atoms, R ₂ is an alkyl group having 1 to 10 carbon atoms, and X is 1 to 40.

In addition, the surfactant represented by Formula 1 is polyoxyethylene glycol ether, polyoxyethylene polyoxypropylene glycol ether, polyoxyethylene alkylphenyl ether, polyoxyethylene alkyl ether, naphthyl polyoxyethylene ether, polyoxyethylene lanolin By mixing and using at least one selected from the group consisting of alcohol ethers and mixtures thereof, the above effects can be further improved. In particular, by mixing and using the surfactant represented by Formula 1 and polyoxyethylene polyoxypropylene glycol ether in a weight ratio of 4:1, the above effect can be further improved.

Then, with respect to 100 parts by weight of at least one pulp selected from the group consisting of softwood pulp, hardwood pulp, old paper pulp, and mixtures thereof, 1000 to 2000 parts by weight of water, 5 to 25 parts by weight of calcium carbonate, 1 to 5% by weight After mixing and stirring 50 to 70 parts by weight of an aqueous solution of calcium hydroxide and 0.1 to 2 parts by weight of citric acid, CO ₂ gas is injected to carbonate, and 5 to 15 parts by weight of a water-soluble polymer are further added while the carbonation is in progress. To prepare a pulp suspension in which calcium is evenly attached to the pulp surface.

Since the pulp contains a large amount of lignin, it is possible to increase the binding power of the pulp molded body, and the wood crushed material can be used after a simple treatment process, thereby reducing manufacturing cost.Since chemical treatment is omitted, environmental pollution caused by chemical treatment It has the effect of maintaining freshness and improving preservation when the object to be packaged is food because it can reduce and absorb quickly and uniformly and has excellent moisture adsorption and gas binding power.

In particular, by using a mixture of softwood pulp, hardwood pulp, and old paper pulp, long and short types of fibers are mixed to form a pulp molded body, so the density of the pulp molded body increases, and the natural mineral and calcium carbonate are dispersed between these fibers. Since it is inserted and fixed, the strength of the pulp molded body is increased, and natural minerals and calcium carbonate are sandwiched between the fibers in a dense state, so that the powder is separated during use of the pulp molded body and is prevented from being mixed into packaging objects such as food. There is an effect.

The calcium carbonate has an average particle diameter of 1 to 100 nm, and has an effect of inducing the growth of calcium carbonate generated by carbonation to be evenly formed between pulp. As a result, there is an effect that the strength of the pulp molded body is remarkably improved.

The citric acid develops pores of calcium carbonate generated by carbonation and is further micronized, thereby having a large specific surface area and excellent reactivity.

The carbonation may be performed by stirring while maintaining a stirring speed of 1000 rpm and a flow rate of CO ₂ gas at 0.7 L/min.

The water-soluble polymer serves to evenly attach calcium carbonate to the pulp surface, and is a water-soluble polymer generally known in the art, and the type is not particularly limited. For example, using a mixture of polymethacrylic acid (PMAA) and water-soluble cellulose in a weight ratio of 2:1 may further improve the above-described effect. At this time, the water-soluble cellulose may preferably be at least one selected from the group consisting of hydroxyethylcellulose (HEC), hydroxypropylmethylcellulose (HPMC), carboxymethylcellulose (CMC), and mixtures thereof. .

Accordingly, it is possible to prepare a pulp suspension in which calcium carbonate having excellent particle shape and dispersion stability is evenly attached to the pulp surface while removing contaminants that may exist in the pulp. As a result, not only the strength of the pulp molded body is remarkably improved, but as a result, the antibacterial performance and gas adsorption ability are excellent.

Then, the natural mineral and calcium carbonate suspension and the pulp suspension are mixed in a weight ratio of 1: 5 to 10, and molded using a mixed solution to obtain a pulp molded body having excellent antibacterial performance and gas adsorption ability and excellent strength. Will be manufactured.

In the mold molding, a mixed solution obtained by mixing the natural mineral and calcium carbonate suspension and the pulp suspension in a weight ratio of 1: 5 to 10 is injected into a lower mold heated to 100 to 400° C., and then 100 to the lower mold. The upper mold heated to 400° C. may be molded to be compressed and molded. More preferably, in consideration of the uniform distribution of the components in the mixed solution and the strength of the final pulp molded body accordingly, the lower and upper molds are preferably heated to 280 to 380°C, respectively.

At this time, between the lower mold and the upper mold each heated to 100 to 400 °C, the mixed solution is continuously heated, and compression/decompression and vacuum/vacuum release are continuously repeated. Thereby, water can be easily and quickly removed, thereby making a pulp molded body possible.

A schematic image of a molding tank for manufacturing a pulp mold according to an embodiment of the present invention is as shown in FIG. 1.

More specifically, when the mixed solution is injected into a molding tank and filled, the lower mold heated to 100 to 400° C. vacuum adsorbs the mixed solution and adheres to the lower mold surface, and water in the mixed solution is It is first removed from the surface of. In this state, the upper mold heated to 100 to 400° C. descends, is molded with the lower mold, and compressed and molded into a product shape, thereby producing a primary molded body containing a small amount of water.

Subsequently, when the vacuum of the lower mold is released and a vacuum is applied to the upper mold, the upper mold vacuum-adsorbs the primary molded body and attaches it to the surface of the upper mold and then raises the upper mold. In this process, a small amount of water contained in the primary molded body is secondarily removed from the upper mold surface by vacuum adsorption. Subsequently, the upper mold is lowered again and molded with the lower mold, and compressed and molded into a product shape, thereby producing a secondary molded body containing a trace amount of water.

Conversely, when the vacuum of the upper mold is released and a vacuum is applied to the lower mold, the lower mold vacuum-adsorbs the secondary molded body and attaches it to the surface of the lower mold and then raises the upper mold. In this process, a trace amount of water contained in the secondary molded body is thirdly removed from the lower mold surface by vacuum adsorption. Subsequently, the upper mold is lowered again to be molded with the lower mold, and compressed and molded into a product shape, thereby producing a tertiary molded body containing a very small amount of water.

In the above, the case where the lower mold is fixed and the upper mold is lowered and raised is illustrated, but the upper mold is fixed and the lower mold is raised or lowered, or the lower mold and the upper mold are alternately raised and lowered as necessary. You may.

In addition, after the first to third molded articles are manufactured, they may be directly heated and dried in a drying device. More specifically, after the first to third molded bodies are manufactured, they are transported by a conveyor belt, and each 100 is heated and dried using various types of heating and drying devices such as a heater, an infrared lamp, and hot air. It can be dried for 3 to 10 minutes at a temperature of to 200 ℃. As a result, the manufacturing time can be shortened, and the above processes can be performed as a continuous process.

Thus, a pulp molded article according to an embodiment of the present invention can be manufactured.

In other words, since the lower and upper molds are alternately vacuum-adsorbed and the water contained in the pulp molded body is alternately removed in the downward and upward directions, the components constituting the pulp molded body can be uniformly distributed without being biased up and down by vacuum adsorption. There is an effect.

In addition, since the heating of the pulp molded body is alternately performed up and down according to the vacuum adsorption of the lower mold and the upper mold, the heat is evenly provided up and down to ensure uniform drying, thereby improving the strength and impact resistance of the pulp molded body. There is. In addition, it is possible to prevent a phenomenon in which the pulp molded body turns black due to high temperature heating.

In addition, since the lower mold and the upper mold are separated by vacuum adsorption of water on either side of the mold, water can be removed from the pulp molded body smoothly, and the lower mold and the upper mold do not simultaneously vacuum adsorption. It is prevented that the strength of the molded body decreases.

In other words, water flows out alternately to the upper and lower portions of the molded body, and the upper and lower portions of the molded body are alternately heated to dry uniformly as a whole.Therefore, no stress remains in the manufactured pulp molded body, resulting in a decrease in strength or damage during use. The occurrence is reduced.

Accordingly, the method of manufacturing a pulp molded article according to an embodiment of the present invention has an effect of providing a pulp molded article having excellent antibacterial performance and gas adsorption ability and excellent strength.

In addition, another embodiment of the present invention provides a pulp molded article manufactured by the method for manufacturing a pulp molded article according to the exemplary embodiment of the present invention.

The pulp molded body according to one embodiment of the present invention exhibits strong antibacterial activity against microorganisms such as fungi, mold and yeast that cause deterioration and decay of contents such as fruits and vegetables, thereby maintaining the freshness of contents such as fruits and vegetables for a long time, thereby providing product value. It has the effect of increasing.

In addition, it has excellent gas adsorption ability to adsorb and remove substances that cause overripe of fruits and vegetables such as ethylene gas, amine, ammonia, acetic acid, etc., solving the problem of rapidly deteriorating freshness due to ethylene gas generated in the cell respiration process of fresh food. It has a very suitable effect as a packaging material for fresh food and/or precision home appliances.

Further, by solving the problem that may cause damage to the product by harmful gases such as carbonic acid or ammonia in a very small amount generated from the inside of the packaging box, there is an effect very suitable as a packaging material for precision machinery such as watches and cameras.

In addition, the pulp molded article according to an embodiment of the present invention has a very excellent tensile strength effect.

Hereinafter, the configuration and effects of the present invention will be described in more detail through examples. However, it is obvious to those skilled in the art that the present invention is not limited to these examples.

Example 1

13 g of zeolite, 34 g of diatomaceous earth, 22 g of illite, and 31 g of pozzolan were pulverized to have a particle size of 250 mesh.

100 g of the pulverized natural mineral, 25 g of calcium carbonate having an average particle diameter of about 578 nm, 7 g of an acrylate-based copolymer (acrylate/acetoacetoxyethyl meth-acrylate copolymer), a surfactant (

) 2g and 700g of water were mixed to prepare a suspension of natural minerals and calcium carbonate having excellent dispersibility.

With respect to the pulp of 37 g of softwood pulp, 37 g of hardwood pulp, and 26 g of old paper pulp, 1800 g of water, 5 g of calcium carbonate having an average particle diameter of about 74 nm, 60 g of a 5% by weight aqueous calcium hydroxide solution, and 0.5 g of citric acid were mixed at a stirring speed of 1000 rpm and While stirring, the gas flow rate was maintained at 0.7 L/min and CO ₂ gas was injected for carbonation, and 6 g of polymethacrylic acid (PMAA) and 3 g of hydroxypropyl methylcellulose (HPMC) were further added during the carbonation process, A pulp suspension with calcium carbonate evenly attached to the pulp surface was prepared.

A mixed solution obtained by mixing 300 g of the prepared natural mineral and calcium carbonate suspension and 1800 g of the pulp suspension was charged into a molding tank as shown in FIG. 1.

The molding tank is equipped with a lower mold and an upper mold, which are engraved on a mold surface to form a box-shaped molded body by combining them with each other, and are capable of moving up and down and are equipped to apply a vacuum to an object placed on the mold surface. After heating the lower mold and the upper mold to 350 ℃, the lower mold is moved below the water surface of the mixed solution filled in the molding tank, and then rises above the water surface so that the pulp composition is contained in the lower mold mold surface, and then stopped and vacuum is applied. Water was first removed.

Subsequently, the upper mold was lowered to be molded and compressed with the lower mold to form a box shape while dehydrating and primary drying to prepare a primary molded body.

Subsequently, the vacuum of the lower mold was released, the upper mold was applied with a vacuum, and the upper mold was raised so that the primary molded body was vacuum-adsorbed to the mold surface of the upper mold and the water in the primary molded body was secondarily removed.

The upper mold is lowered again so that it is molded and compressed with the lower mold to produce a secondary dried secondary molded body, and then the vacuum of the upper mold is released, a vacuum is applied to the lower mold, and the upper mold is raised to lower the secondary molded body. It was vacuum-adsorbed on the mold surface of the mold so that water in the secondary molded body was thirdly removed.

Subsequently, the upper mold was lowered again to be molded and compressed with the lower mold to produce a third-dried third molded body.After raising the upper mold, the vacuum of the lower mold was released and the third molded body was taken out to remove the pulp molded body. Was prepared.

Test Example 1: Antibacterial performance test

The pulp molded article prepared in the above example was commissioned to the Korea Institute of Construction Living Environment Test and tested for antibacterial performance, and the results are shown in Tables 1, 2, and 3. Test strains were Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 6538), pneumonia (Klebsiella pneumoniae, ATCC 4352), and Salmonella (Salmonella Enterica, KCTC 1925), KS K 0693:2006 Test Method It was tested according to.

Test Items		Test result at (37.0±0.2)℃
		Initial bacterial count (CFU/mL)	Count of bacteria after 18 hours (CFU/mL)	Bacterial reduction rate (%)
Coli	Example	3.1×10 5	<50	99.9
	Control		8.0×10 7	-
Staphylococcus aureus	Example	2.3×10 5	<50	99.9
	Control		2.9×10 8	-
Pneumonia	Example	3.6×10 5	<50	99.9
	Control		1.7×10 8	-
Salmonella	Example	2.4×10 5	<50	99.9
	Control		1.1×10 8	-

As can be seen in Table 1, the bacteria proliferated in the control piece (stomacher film) after 18 hours, but in the pulp molded body according to the example, the bacteria were killed, and the bacterial reduction rate was measured to be 99.9%. In addition, this could be confirmed through the visual observation result images of FIGS. 2 (pneumococcal) and 3 (Salmonella).

Accordingly, it was confirmed that the pulp molded article of the example had very excellent antibacterial activity.

Test Example 2: Analysis of ethylene content change during fruit storage

The apples were put in the pulp mold (box) prepared in the above example, sealed, and stored for 14 days, and then the changes in ethylene content 1 and 14 days after storage were analyzed and shown in Table 2 below. At this time, the ethylene content analysis was performed using a gas chromatography (GC-14B, Shimadzu, Japan) equipped with a TCD (thermal conductivity detector) after collecting air in the box with a syringe syringe, and helium (helium) as the carrier gas. , 20 cc/min) was used, and Porapak Q (80~100 mesh, 3 ㎜Φ×2 m,stainless steel tube) was used as a packing material for analysis. As a control, apples were put in a normal cardboard box and stored for 14 days, and then compared with the above example.

Mg/ℓ	1 day	14 days
Example	3.52±0.37	6.12±1.41
Control	2.15±0.56	9.85±0.89

As can be seen in Table 2 above, it can be seen that the pulp molded body (box) according to the embodiment of the present invention adsorbs ethylene gas generated from apples, and after 14 days storage, the ethylene gas content in the box is less than that of a general corrugated box. there was. As a result, it is judged that the product's marketability can be improved by suppressing overripe during storage of apples, maintaining freshness for a long time and extending the shelf life.

Test Example 3: Noxious gas adsorption ability test

For the pulp molded article prepared in the above example, gas adsorption properties were evaluated. For gas adsorption characteristics, the pulp molded body was cut into 5 cm × 5 cm × 0.37 mm (width × length × thickness) and then put in a desiccator and exposed to ammonia gas for 7 days. Thereafter, the ammonia adsorption amount was measured by the following method and is shown in Table 3 below. At this time, the ammonia adsorption amount (µl/kg) was performed according to KS M 1998-4. In addition, as a control, a general cardboard box was used to compare gas adsorption properties.

Μl/kg	Ammonia adsorption amount
Example	852
Control	49

As can be seen in Table 3, it was confirmed that the pulp molded article according to the embodiment of the present invention has a very excellent effect of adsorbing harmful gases such as ammonia. As a result, it is judged to be very suitable as a wrapping paper for fresh food and/or precision home appliances.

Test Example 4: Measurement of tensile strength

For the pulp molded body prepared in the above example, the tensile strength was evaluated. The tensile strength evaluation was performed according to KS M 7014. The measured tensile strength is shown in Table 4 below. In addition, as a control, a general cardboard box was used to compare the tensile strength.

(kN/m)	The tensile strength
Example	54
Control	21

As can be seen in Table 4, the pulp molded article according to the embodiment of the present invention can provide a pulp molded article having a very improved strength and less damage.

As described above, those skilled in the art to which the present invention pertains will understand that the present invention can be implemented in other specific forms without changing the technical spirit or essential features. Therefore, all the embodiments described above are illustrative and should be understood as non-limiting. The scope of the present invention should be construed as including all altered or modified forms derived from the meaning and scope of the claims to be described later rather than the above detailed description, and equivalent concepts thereof.

Claims (4)

1. Pulverizing a particle size of 200 to 500 mesh for at least one natural mineral selected from the group consisting of zeolite, diatomaceous earth, illite, pozzolan, and mixtures thereof;

   With respect to 100 parts by weight of the pulverized natural mineral, 10 to 30 parts by weight of calcium carbonate, 5 to 15 parts by weight of an acrylate-based copolymer, 1 to 5 parts by weight of a surfactant, and 500 to 1000 parts by weight of water are mixed to provide excellent dispersibility. Preparing a suspension of natural minerals and calcium carbonate;

   With respect to 100 parts by weight of at least one pulp selected from the group consisting of softwood pulp, hardwood pulp, old paper pulp, and mixtures thereof, water at a concentration of 1000 to 2000 parts by weight, calcium carbonate 5 to 25 parts by weight, 1 to 5% by weight After mixing and stirring 50 to 70 parts by weight of an aqueous calcium hydroxide solution and 0.1 to 2 parts by weight of citric acid, CO ₂ gas is injected to carbonate, and 5 to 15 parts by weight of a water-soluble polymer are further added while the carbonation is in progress. Preparing a pulp suspension evenly attached to the pulp surface; And

   A pulp molded article comprising the step of forming a pulp molded body by molding using a mixture solution of the natural mineral and calcium carbonate suspension and the pulp suspension in a weight ratio of 1:5 to 10 Manufacturing method.
2. The method of claim 1,

   In the step of preparing a suspension of the natural mineral and calcium carbonate,

   The calcium carbonate has an average particle diameter of 100 to 700 nm,

   The acrylate-based copolymer is at least one acrylate selected from the group consisting of an acrylate/acrylamide copolymer, an acrylate/acetoacetoxyethylmeth-acrylate copolymer, and an acrylate/C10-C30 alkyl acrylate crosspolymer It is a system copolymer,

   The surfactant is a method of producing a pulp mold, characterized in that the compound represented by the following formula (1).

   [Formula 1]

   

   In Formula 1, R ₁ is an alkyl group having 5 to 20 carbon atoms, R ₂ is an alkyl group having 1 to 10 carbon atoms, and X is 1 to 40.
3. The method of claim 1,

   In the step of preparing the pulp suspension,

   The calcium carbonate has an average particle diameter of 1 to 100 nm,

   The water-soluble polymer is a method for producing a pulp molded article, characterized in that a mixture of polymethacrylic acid (PMAA) and water-soluble cellulose in a weight ratio of 2:1.
4. A pulp molded article produced by the method for producing a pulp molded article according to any one of claims 1 to 3.

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