WO2023234670A1

WO2023234670A1 - Biodegradable aqueous dispersion solution, and biodegradable product and manufacturing method therefor

Info

Publication number: WO2023234670A1
Application number: PCT/KR2023/007366
Authority: WO
Inventors: 박소연; 심유경; 윤기철
Original assignee: 씨제이제일제당(주)
Priority date: 2022-05-31
Filing date: 2023-05-30
Publication date: 2023-12-07
Also published as: KR20230166693A

Abstract

The present invention relates to a biodegradable aqueous dispersion solution, and a biodegradable product and a manufacturing method therefor. Specifically, according to one embodiment of the present invention, a biodegradable aqueous dispersion solution comprises a polyhydroxyalkanoate, water and a polyol, which has an average degree of polymerization of 100-25,000, so as to have a drying rate at 170°C, according to relation 1, of 7.0 g/m2·s or less, and thus has excellent biodegradability and biocompatibility, thereby improving pH, viscosity characteristics, dispersibility and storage stability while being eco-friendly.

Description

Biodegradable aqueous dispersion, and biodegradable article and method for producing the same

The present invention relates to biodegradable aqueous dispersions, and biodegradable articles and methods for producing the same.

Recently, as concerns about environmental issues have increased, research on the treatment and recycling of various household waste has been actively conducted. Specifically, polymer materials that are inexpensive and have excellent properties such as processability are widely used to manufacture various products such as paper, film, fiber, packaging materials, bottles, containers, etc. However, when these products reach the end of their lifespan, they are harmful when incinerated. It has the disadvantage that substances can be released and that it takes hundreds of years depending on the type to completely decompose naturally.

Accordingly, biodegradable polymers can improve eco-friendliness by decomposing quickly, while increasing the lifespan of the product itself by improving mechanical properties, oil resistance, water resistance, and processability, thereby reducing the amount of waste or improving recyclability. Research on this is continuing.

Polyhydroxyalkanoates (PHA) are biodegradable polymers composed of several types of hydroxy carboxylic acids produced by numerous microorganisms and used as intracellular storage substances. Polyhydroxyalkanoates are polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS), and polybutylene succinate derived from conventional petroleum. It has similar physical properties to synthetic polymers such as terephthalate (PBST) and polybutylene succinate adipate (PBSA), is completely biodegradable, and has excellent biocompatibility.

Meanwhile, in order to improve the service life and recyclability of various products such as paper, film, fiber, packaging materials, bottles, containers, etc., it is important to improve mechanical properties such as strength, oil resistance, and water resistance. In particular, food packaging materials that pack foods with a lot of moisture or oil, such as fruits, vegetables, bread, cookies, ice cream, etc., have problems with moisture or oil seeping from the food, tearing the packaging material, contaminating the food, or having a short service life.

In order to improve these mechanical properties, water resistance, and oil resistance, a process of forming a coating layer on the surface of the product is used, but there is a problem that biodegradability and recyclability are reduced due to the coating layer. For example, the biodegradability of the coating layer component that can improve water resistance and oil resistance is low, or even if the biodegradability of the coating layer is excellent, the lifespan of the product may be poor due to low storage stability, and the coating layer may be removed from the surface of a used product. Additional processes may be required to do this. Therefore, research is continuing on biodegradable dispersions that are environmentally friendly due to their excellent biodegradability and biocompatibility, and have excellent dispersibility, storage stability, water resistance, oil resistance, coating properties, and processability.

[Prior art literature]

[Patent Document]

(Patent Document 1) Korean Patent Publication No. 2012-0103158

Therefore, the present invention provides a biodegradable aqueous dispersion that is environmentally friendly due to its excellent biodegradability and biocompatibility, has excellent dispersibility and storage stability, which can improve the lifespan of biodegradable articles using it, and also has excellent coating properties, water resistance, and processability, and The object is to provide a biodegradable article and a method for manufacturing the same.

The biodegradable aqueous dispersion according to an embodiment of the present invention includes polyhydroxyalkanoate; water; and a polyol having an average degree of polymerization of 100 to 25,000, and a drying rate at 170° C. according to Equation 1 below of 7.0 g/m ² ·s or less.

[Equation 1]

According to one embodiment of the present invention, the biodegradable aqueous dispersion may include 0.1% by weight to 15% by weight of the polyol based on the total weight of solid content.

According to one embodiment of the present invention, the biodegradable aqueous dispersion may have a drying rate of 6.0 g/m ² ·s or less at 170° C. according to Equation 1 above. ,

According to one embodiment of the present invention, the biodegradable aqueous dispersion is polyacrylate-based, polyvinyl alcohol, polyvinylpyrrolidone, methylpolyethylene alkyl ether, sodium dodecylbenzene sulfonate, alkylbenzene sulfonate, and nonylphenol ether. It may include one or more dispersants selected from the group consisting of sulfate, sodium lauryl sulfate, lithium dodecyl sulfate, alkyl phosphate, and polypropylene glycol ester.

According to one embodiment of the present invention, the dispersant may include a polyacrylate-based dispersant, and the polyacrylate-based dispersant may be an anionic dispersant having a carboxylic acid functional group.

According to one embodiment of the present invention, the biodegradable aqueous dispersion may include 0.01% by weight to 12% by weight of the dispersant based on the total weight of solids.

According to one embodiment of the present invention, the polyhydroxyalkanoate is 3-hydroxybutyrate (3-HB), 4-hydroxybutyrate (4-HB), 3-hydroxypropionate (3-HP) ), 3-hydroxyhexanoate (3-HH), 3-hydroxyvalerate (3-HV), 4-hydroxyvalerate (4-HV), 5-hydroxyvalerate (5-HV) and 6-hydroxyhexanoate (6-HH).

According to one embodiment of the present invention, the polyhydroxyalkanoate is a copolymerized polyhydroxyalkanoate comprising a 4-hydroxybutyrate (4-HB) repeating unit and a 3-hydroxybutyrate (3-HB) repeating unit. As decanoate, it may contain 0.1% to 60% by weight of the 4-hydroxybutyrate (4-HB) repeating unit.

According to one embodiment of the present invention, the biodegradable aqueous dispersion may have a viscosity of 105 mPa·s to 2,500 mPa·s and a pH of more than 7.

According to one embodiment of the present invention, the average particle size of polyhydroxyalkanoate in the biodegradable aqueous dispersion may be 0.5 ㎛ to 5 ㎛.

According to one embodiment of the present invention, the solid content of the biodegradable aqueous dispersion may be 10% by weight to 60% by weight.

A method for producing a biodegradable article according to another embodiment of the present invention includes preparing a biodegradable aqueous dispersion; And forming a biodegradable coating layer on at least one side of the substrate using the biodegradable aqueous dispersion, wherein the biodegradable aqueous dispersion includes polyhydroxyalkanoate, water, and a polyol having an average degree of polymerization of 100 to 25,000. and the drying rate at 170°C according to Equation 1 above is 7.0 g/m ² ·s or less.

According to another embodiment of the present invention, forming the biodegradable coating layer may include applying and drying the biodegradable aqueous dispersion, and the application is 3 g/m ² to 50 g/m ² It can be performed in an application amount, and the drying can be performed at 120°C to 200°C for 5 seconds to 10 minutes.

A biodegradable article according to another embodiment of the present invention includes a substrate; and a biodegradable coating layer on at least one side of the substrate, wherein the biodegradable coating layer is formed using a biodegradable aqueous dispersion, and the biodegradable aqueous dispersion is polyhydroxyalkanoate, water, and an average degree of polymerization of 100 to 25,000. It contains phosphorus polyol, and the drying rate at 170°C according to Equation 1 above is 7.0 g/m ² ·s or less.

According to another embodiment of the present invention, the water resistance of the biodegradable coating layer may be less than 27 g/m ² .

The biodegradable aqueous dispersion according to an embodiment of the present invention includes polyhydroxyalkanoate, water, and a polyol with an average degree of polymerization of 100 to 25,000, so that the drying rate at 170 ° C. according to Equation 1 is 7.0 g / m Since it satisfies ² ·s or less, it has excellent biodegradability and biocompatibility, making it environmentally friendly and improving pH and viscosity characteristics, dispersibility, and storage stability.

In particular, the biodegradable aqueous dispersion according to the present invention contains a polyol with an average degree of polymerization of 100 to 25,000, so when coating it, the drying time can be shortened, thereby improving productivity and processability.

Therefore, the biodegradable aqueous dispersion not only has excellent coating properties, water resistance, and processability, but also when biodegradable products manufactured using it are applied to products that require water resistance, such as food packaging materials for packaging foods with high moisture content. , it can demonstrate excellent characteristics. In addition, the biodegradable aqueous dispersion has excellent viscosity characteristics and storage stability, which can improve the lifespan of biodegradable products using it.

Hereinafter, the present invention will be described in detail. The present invention is not limited to the content disclosed below, and may be modified into various forms as long as the gist of the invention is not changed.

In this specification, when a part “includes” a certain component, this means that it may further include other components rather than excluding other components, unless specifically stated to the contrary.

All numbers and expressions indicating the amounts of components, reaction conditions, etc. described in this specification should be understood as being modified by the term “about” in all cases unless otherwise specified.

In this specification, when one component is described as being formed on or under another component, it means that one component is formed directly on or under the other component, or indirectly through another component. Includes.

생분해성 수계 분산액Biodegradable aqueous dispersion

[Equation 1]

While polyhydroxyalkanoate has excellent biodegradability and biocompatibility, coating of a dispersion containing it requires drying at high temperature for a long time, so processability may be relatively low. The biodegradable aqueous dispersion according to an embodiment of the present invention contains a polyol, especially a polyol having a specific average degree of polymerization suitable for the polyhydroxyalkanoate according to the present invention, so that the drying time can be shortened when coating it. Productivity and processability can be improved.

Specifically, the biodegradable aqueous dispersion may have a drying rate of 7.0 g/m ² ·s or less at 170°C according to Equation 1 above. For example, the biodegradable aqueous dispersion has a drying rate at 170°C according to Equation 1 of 6.8 g/m ² ·s or less, 6.2 g/m ² ·s or less, 6.0 g/m ² ·s or less, 5.6 It may be g/m ² ·s or less or 5.5 g/m ² ·s or less.

The viscosity of the biodegradable aqueous dispersion may be 105 mPa·s to 2,500 mPa·s. For example, the viscosity of the biodegradable aqueous dispersion may be 105 mPa·s to 2,400 mPa·s, 105 mPa·s to 2,300 mPa·s, or 110 mPa·s to 2,250 mPa·s.

Additionally, the pH of the biodegradable aqueous dispersion may be greater than 7. For example, the pH of the biodegradable aqueous dispersion may be 7.1 or higher, 7.3 or higher, 7.5 or higher, or 7.7 or higher, and may be greater than 7 to 12 or lower, 7.1 to 11, 7.3 to 10, 7.6 to 9, or 7.8 to 8. . When the pH of the biodegradable aqueous dispersion satisfies the above range, dispersion stability, processability, and storage stability can be improved due to the negative charge on the outside of the particles.

The solid content of the biodegradable aqueous dispersion may be 10% by weight to 60% by weight. For example, the solid content of the biodegradable aqueous dispersion is 15% to 55% by weight, 20% to 55% by weight, 25% to 50% by weight, 30% to 45% by weight, or 35% to 45% by weight. It may be weight percent.

The average particle size of the polyhydroxyalkanoate in the biodegradable aqueous dispersion may be 0.5 ㎛ to 5 ㎛. For example, the average particle size of the polyhydroxyalkanoate in the biodegradable aqueous dispersion is 0.7 ㎛ to 4.6 ㎛, 1.1 ㎛ to 4.5 ㎛, 1.5 ㎛ to 4.3 ㎛, 2.2 ㎛ to 4.2 ㎛, 2.6 ㎛ to 4.0 ㎛. ㎛, 2.8 ㎛ to 3.9 ㎛ or 3.1 ㎛ to 3.8 ㎛.

Polyhydroxyalkanoate

The biodegradable aqueous dispersion according to an embodiment of the present invention includes polyhydroxyalkanoate (PHA).

The PHA is a thermoplastic natural polyester polymer that accumulates in microbial cells. Since it is a biodegradable material, it can be composted and biodegraded in the ocean, and can ultimately be decomposed into carbon dioxide, water, and organic waste without generating toxic waste.

Specifically, PHA is a thermoplastic natural polyester polymer that accumulates within microbial cells. When certain bacteria are unbalanced with nutrients (nitrogen source, phosphorus, etc.), they accumulate PHA within cells to store carbon sources and energy. It is formed by doing

In addition, the PHA is polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS), polybutylene succinate terephthalate (PBST), and polybutylene succinate adipate (PBAT) derived from existing petroleum. It has similar physical properties to synthetic polymers such as (PBSA), is completely biodegradable, and has excellent biocompatibility.

In particular, unlike other eco-friendly plastic materials such as PBS, PLA, and PTT, PHA can be synthesized from more than 150 types of monomers, so hundreds of types of PHA can be manufactured depending on the type of monomer, and different types of PHA can be produced depending on the type of monomer. Hundreds of types of PHAs each have completely different structures and properties.

The PHA may be composed of a single monomer repeating unit within living cells, or may be formed by polymerizing one or more monomer repeating units. Specifically, the PHA may be a single polyhydroxyalkanoate (hereinafter referred to as HOMO PHA), or a copolymerized polyhydroxyalkanoate (hereinafter referred to as copolymer PHA), i.e., a polymer chain with different repeating units. It may be a copolymer in which they are randomly distributed.

Examples of repeating units that may be included in the PHA include 2-hydroxybutyrate, lactic acid, glycolic acid, 3-hydroxybutyrate (hereinafter referred to as 3-HB), 3-hydroxypropionate (hereinafter referred to as 3) -HP), 3-hydroxyvalerate (hereinafter referred to as 3-HV), 3-hydroxyhexanoate (hereinafter referred to as 3-HH), 3-hydroxyheptanoate (hereinafter referred to as 3-HH) Hereinafter referred to as 3-HHep), 3-hydroxyoctanoate (hereinafter referred to as 3-HO), 3-hydroxynonanoate (hereinafter referred to as 3-HN), 3-hydroxy Decanoate (hereinafter referred to as 3-HD), 3-hydroxydodecanoate (hereinafter referred to as 3-HDd), 4-hydroxybutyrate (hereinafter referred to as 4-HB), 4- Hydroxyvalerate (hereinafter referred to as 4-HV), 5-hydroxyvalerate (hereinafter referred to as 5-HV), and 6-hydroxyhexanoate (hereinafter referred to as 6-HH) There may be, and the PHA may contain one or more repeating units selected from these.

Specifically, the PHA is 3-HB, 4-HB, 3-HP, 3-HH. It may contain one or more repeating units selected from the group consisting of 3-HV, 4-HV, 5-HV and 6-HH.

More specifically, the PHA may contain 0.1% to 100% by weight of the 4-HB repeating unit. For example, the PHA contains 4-HB repeating units in an amount of 0.2 to 100 wt%, 0.5 to 100 wt%, 1 to 100 wt%, 5 wt% to 100 wt%, 10 wt% to 100 wt%, and 20 wt%. to 100% by weight, 30% to 100% by weight, 40% to 100% by weight, 50% to 100% by weight, 60% to 100% by weight, 70% to 100% by weight, 80% to 100% by weight. It may be included in weight% or 90% to 100% by weight. That is, the PHA may be a HOMO PHA consisting only of 4-HB repeating units, or it may be a copolymer PHA containing a 4-HB repeating unit.

In addition, the PHA includes a 4-HB repeating unit and additionally includes one repeating unit different from the 4-HB, or 2, 3, 4, 5, 6 or more repeating units different from each other. It may be a copolymer PHA further comprising. For example, the PHA may be poly 3-hydroxybutyrate-co-4-hydroxybutyrate (hereinafter referred to as 3HB-co-4HB).

Additionally, the PHA may include isomers. For example, the PHA may include structural isomers, enantiomers, or geometric isomers. Specifically, the PHA may include structural isomers.

Additionally, the PHA may be a copolymer PHA with controlled crystallinity. For example, the PHA may include at least one 4-HB repeating unit, and the crystallinity of the PHA can be adjusted by controlling the content of the 4-HB repeating unit.

For example, the PHA is 3-hydroxybutyrate (3-HB), 4-hydroxybutyrate (4-HB), 3-hydroxypropionate (3-HP), 3-hydroxyhexanoate ( 3-HH), 3-hydroxyvalerate (3-HV), 4-hydroxyvalerate (4-HV), 5-hydroxyvalerate (5-HV) and 6-hydroxyhexanoate (6 It may be a copolymer PHA containing one or more repeating units selected from the group consisting of -HH).

Specifically, the copolymerized PHA includes a 4-HB repeating unit, a 3-HB repeating unit, a 3-HP repeating unit, a 3-HH repeating unit, a 3-HV repeating unit, a 4-HV repeating unit, and a 5-HV repeating unit. It may further include one or more repeating units selected from the group consisting of a unit and a 6-HH repeating unit. More specifically, the copolymerized PHA may include a 4-HB repeating unit and a 3-HB repeating unit.

More specifically, the PHA is a copolymer PHA containing a 4-HB repeating unit and a 3-HB repeating unit, and may include the 4-HB repeating unit in an amount of 0.1% to 60% by weight. For example, the PHA may contain the 4-HB repeating unit in an amount of 0.1% to 55% by weight, 0.5% to 50% by weight, 1% to 48% by weight, 2% to 45% by weight, or 5% to 5% by weight. It may be included at 35% by weight, 6% by weight to 20% by weight, 8% by weight to 15% by weight, or 9% by weight to 12% by weight.

In addition, the PHA is a copolymer PHA containing a 4-HB repeating unit and a 3-HB repeating unit, and may contain 20% by weight or more of the 3-HB repeating unit. For example, the PHA may contain more than 35% by weight, more than 40% by weight, more than 50% by weight, more than 60% by weight, more than 70% by weight, or more than 75% by weight, 99 Weight% or less, 98 weight% or less, 97 weight% or less, 96 weight% or less, 95 weight% or less, 93 weight% or less, 91 weight% or less, 90 weight% or less, 80 weight% or less, 70 weight% or less, 60 It may be included in weight% or less or 55% by weight or less.

The PHA with controlled crystallinity may have its crystallinity and amorphousness adjusted by increasing the irregularity in the molecular structure. Specifically, it may be one by adjusting the type or ratio of monomers or the type or content of isomers.

According to one embodiment of the present invention, the PHA may include two or more types of PHA with different crystallinity. Specifically, the PHA may be adjusted to have the content of the 4-HB repeating unit within the specific range by mixing two or more types of PHAs with different crystallinities.

Specifically, the PHA may include a first PHA that is a semi-crystalline PHA.

The first PHA is a semi-crystalline PHA with controlled crystallinity (hereinafter referred to as scPHA), and may include 0.1% by weight to 30% by weight of a 4-HB repeating unit. For example, the first PHA contains 4-HB repeating units in an amount of 0.5% to 30% by weight, 1% to 30% by weight, 3% to 30% by weight, 1% to 28% by weight, 1% by weight. to 25% by weight, 1% to 24% by weight, 1% to 15% by weight, 2% to 25% by weight, 3% to 25% by weight, 3% to 24% by weight, 5% to 24% by weight It may be included in weight%, 7% to 20% by weight, 10% to 20% by weight, 15% to 25% by weight, or 15% to 24% by weight.

The glass transition temperature (Tg) of the first PHA is -30°C to 80°C, -30°C to 10°C, -25°C to 5°C, -25°C to 0°C, -20°C to 0°C, or -15°C. It may be from 0°C. The crystallization temperature (Tc) of the first PHA may be 70°C to 120°C, 75°C to 120°C, or 75°C to 115°C, and the melting temperature (Tm) of the first PHA may be 105°C to 165°C, 110°C. It may be ℃ to 160℃, 115℃ to 155℃ or 120℃ to 150℃.

The weight average molecular weight of the first PHA is 10,000 g/mol to 1,200,000 g/mol, 50,000 g/mol to 1,100,000 g/mol, 100,000 g/mol to 1,000,000 g/mol, 100,000 g/mol to 900,000 g/mol, 200,000 g /mol to 800,000 g/mol, 200,000 g/mol to 600,000 g/mol, or 200,000 g/mol to 400,000 g/mol.

Additionally, the PHA may include a second PHA, which is an amorphous PHA with controlled crystallinity.

The second PHA is an amorphous PHA with controlled crystallinity (hereinafter referred to as aPHA), and contains 4-HB repeating units in an amount of 15% to 60% by weight, 15% to 55% by weight, and 20% to 55% by weight. %, 25% to 55% by weight, 30% to 55% by weight, 35% to 55% by weight, 20% to 50% by weight, 25% to 50% by weight, 30% to 50% by weight, It may contain 35% to 50% by weight or 20% to 40% by weight.

The glass transition temperature (Tg) of the second PHA may be -45°C to -10°C, -35°C to -15°C, -35°C to -20°C, or -30°C to -20°C.

Additionally, the crystallization temperature (Tc) of the second PHA may not be measured, or may be 60°C to 120°C, 60°C to 110°C, 70°C to 120°C, or 75°C to 115°C. The melting temperature (Tm) of the second PHA may not be measured, or may be 100°C to 170°C, 100°C to 160°C, 110°C to 160°C, or 120°C to 150°C.

The average molecular weight of the second PHA is 10,000 g/mol to 1,200,000 g/mol, 10,000 g/mol to 1,000,000 g/mol, 50,000 g/mol to 1,000,000 g/mol, 200,000 g/mol to 1,200,000 g/mol, 300,000 g/mol to 1,000,000 g/mol, 100,000 g/mol to 900,000 g/mol, 500,000 g/mol to 900,000 g/mol, 200,000 g/mol to 800,000 g/mol, or 200,000 g/mol to 400,000 g/mol. there is.

The first PHA and the second PHA can be distinguished depending on the content of the 4-HB repeating unit, and are selected from the group consisting of the glass transition temperature (Tg), the crystallization temperature (Tc), and the melting temperature (Tm). It can have at least one characteristic. Specifically, the first PHA and the second PHA can be distinguished according to the content of 4-HB repeating units, glass transition temperature (Tg), crystallization temperature (Tg), melting temperature (Tm), etc.

According to one embodiment of the present invention, the PHA may include the first PHA, or may include both the first PHA and the second PHA.

Specifically, the PHA includes a first PHA that is a semi-crystalline PHA, or includes both a first PHA that is a semi-crystalline PHA and a second PHA that is an amorphous PHA, and more specifically, the content of the first PHA and the second PHA. By controlling , the yield of the desired material can be more effectively controlled.

In addition, the glass transition temperature (Tg) of the PHA is -45°C to 80°C, -35°C to 80°C, -30°C to 80°C, -25°C to 75°C, -20°C to 70°C, -35°C. to 5℃, -25℃ to 5℃, -35℃ to 0℃, -25℃ to 0℃, -30℃ to -10℃, -35℃ to -15℃, -35℃ to -20℃, - It may be 20°C to 0°C, -15°C to 0°C, or -15°C to -5°C.

The crystallization temperature (Tc) of the PHA is not measured, or is 60°C to 120°C, 60°C to 110°C, 70°C to 120°C, 75°C to 120°C, 75°C to 115°C, 75°C to 110°C, or 90°C. It may be from ℃ to 110℃.

Additionally, the weight average molecular weight of the PHA may be 10,000 g/mol to 1,200,000 g/mol. For example, the weight average molecular weight of the PHA is 50,000 g/mol to 1,200,000 g/mol, 100,000 g/mol to 1,000,000 g/mol, 200,000 g/mol to 1,200,000 g/mol, 250,000 g/mol to 1,150,000 g/mol. , 300,000 g/mol to 1,100,000 g/mol, 350,000 g/mol to 950,000 g/mol, 100,000 g/mol to 900,000 g/mol, 200,000 g/mol to 800,000 g/mol, 250,000 g/mol to 650,000 g/ mol , 200,000 g/mol to 400,000 g/mol, 300,000 g/mol to 600,000 g/mol, 500,000 g/mol to 1,200,000 g/mol, 500,000 g/mol to 1,000,000 g/mol 550,000 g/mol to 1,050,00 0 g/mol, It may be 550,000 g/mol to 900,000 g/mol, 600,000 g/mol to 900,000 g/mol or 500,000 g/mol to 900,000 g/mol.

The crystallinity of the PHA measured by differential scanning calorimeter (DSC) may be 90% or less. For example, the crystallinity of the PHA may be measured by differential scanning heat capacity analysis and may be 90% or less, 85% or less, 80% or less, 75% or less, or 70% or less.

Additionally, the average particle size of the PHA may be 0.5 ㎛ to 5 ㎛. For example, the average particle size of PHA in the biodegradable aqueous dispersion is 0.7 ㎛ to 4.6 ㎛, 1.1 ㎛ to 4.5 ㎛, 1.5 ㎛ to 4.3 ㎛, 2.2 ㎛ to 4.2 ㎛, 2.6 ㎛ to 4.0 ㎛, 2.8 ㎛ to 3. 9 It may be ㎛ or 3.1 ㎛ to 3.8 ㎛.

The average particle size of the PHA can be measured using a nano particle size analyzer (ex. Zetasizer Nano ZS). Specifically, for the PHA, the average particle size was measured using the principle of dynamic light scattering (DLS) at a temperature of 25°C and a measurement angle of 175° using Zetasizer Nano ZS (manufacturer: Marven). At this time, the peak value derived through the polydispersity index (PDI) at a confidence interval of 0.5 was measured as the particle size.

The polydispersity index (PDI) of the PHA may be less than 2.5. For example, the polydispersity index of the PHA may be less than 2.5, less than 2.3, less than 2.1, or less than 2.0.

Additionally, the PHA may be obtained by cell disruption using a non-mechanical method or a chemical method. Specifically, the PHA is a thermoplastic natural polyester polymer that accumulates in microbial cells and has a relatively large average particle size, so it was obtained through a crushing process to more effectively control the yield of the desired material and improve process efficiency. It may be.

polyol

The biodegradable aqueous dispersion according to an embodiment of the present invention includes polyol with an average degree of polymerization of 100 to 25,000.

Specifically, the polyol may be one or more selected from the group consisting of polyethylene glycol, polypropylene glycol, polybutylene glycol, polytetramethylene ether glycol, and polyoxypropylene glycol. Preferably, the polyol may be polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, or polyoxypropylene glycol, and more preferably, it may be polyethylene glycol.

For example, the average degree of polymerization of the polyol may be 120 to 23,000, 150 to 22,500, 180 to 21,000, 200 to 20,000, 150 to 8,000, 200 to 65,000, or 5,000 to 21,000. When the average degree of polymerization of the polyol satisfies the above range, dispersion stability and processability can be further improved.

Additionally, the biodegradable aqueous dispersion may contain 0.1% to 15% by weight of the polyol based on the total weight of solids. For example, the content of the polyol is 0.1% to 14% by weight, 0.5% to 12.5% by weight, 1% to 12% by weight, or 2% to 12% by weight, based on the total weight of solids of the biodegradable aqueous dispersion. It may be weight percent.

The content of the polyol can be adjusted depending on the average degree of polymerization of the polyol. Specifically, by adjusting the weight portion according to the average degree of polymerization of the polyol to maximize compatibility with PHA, viscosity characteristics, dispersion stability, water resistance, and processability can be further improved.

For example, when the average degree of polymerization of a suitable polyol according to the PHA is 200 or more to less than 400, the content of the polyol is 6% by weight to 15% by weight, 7.5% by weight to 14% by weight, or 9% by weight based on the total weight of solids. It may be from 12.5% by weight. In addition, when the average degree of polymerization of a suitable polyol according to the PHA is 400 or more to less than 6,000, the content of the polyol is 3% by weight to 13% by weight, 3.5% by weight to 10% by weight, or 5% by weight to 8% by weight based on the total weight of solids. It may be % by weight or 5.5% to 7% by weight. In addition, when the average degree of polymerization of the polyol suitable for the PHA is 6,000 to 25,000, the content of the polyol is 0.1% by weight to 9% by weight, 0.5% by weight to 8.5% by weight, and 1.5% by weight to 8% by weight based on the total weight of solids. % or 2.5% to 7.5% by weight.

dispersant

The biodegradable aqueous dispersion according to an embodiment of the present invention may include a dispersant.

Specifically, the dispersant may be one or more selected from the group consisting of phosphoric acid-based dispersants, fatty acid-based dispersants, acrylic-based dispersants, urethane-based dispersants, and epoxy-based dispersants, and may be selected from the group consisting of carboxylic acids, amines, isocyanates, and derivatives thereof. It may be a polymer dispersant containing one or more types.

More specifically, the dispersant is polyacrylate-based, polyvinyl alcohol, polyvinylpyrrolidone, methylpolyethylene alkyl ether, sodium dodecylbenzene sulfonate, alkylbenzene sulfonate, nonylphenol ether sulfate, sodium lauryl sulfate, and lithium. It may include one or more selected from the group consisting of dodecyl sulfate, alkyl phosphate, and polypropylene glycol ester.

Additionally, the dispersant may include an anionic dispersant. For example, the anionic dispersant may include an acid functional group such as phosphoric acid, sulfuric acid, or carboxylic acid, or a salt thereof.

According to one embodiment of the present invention, the dispersant may include a polyacrylate type. Specifically, the dispersant may be an anionic dispersant having a carboxylic acid functional group, and when used together with the PHA and polyol, it may be most preferable in that it can maximize viscosity characteristics and storage stability.

According to another embodiment of the present invention, the dispersant may be polyvinyl alcohol.

Polyvinyl alcohol can be obtained by polymerizing polyvinyl acetate (PVAc) and then substituting the hydrophobic CH ₃ COO- with the hydrophilic -OH through a hydrolysis reaction, where -OH is substituted for the total amount. The degree, that is, the ratio of CH ₃ COO- and -OH, is the degree of saponification. That is, the degree of saponification may vary depending on the molecular weight or distribution characteristics of polyvinyl alcohol during the -OH substitution reaction, and may affect the final resin physical properties.

Specifically, the degree of saponification of the polyvinyl alcohol may be 80 mol% to 98 mol%. For example, the degree of saponification of the polyvinyl alcohol may be 82 mol% to 98 mol% or 85 mol% to 98 mol%.

When the degree of saponification of polyvinyl alcohol satisfies the above range, dispersibility and storage stability can be improved, and an appropriate viscosity for coating can be obtained, thereby improving coating properties, productivity, and processability. Specifically, if the degree of saponification is outside the above range, the solubility or dispersibility of the dispersant may be greatly reduced, making it impossible to form a coating layer using a biodegradable aqueous dispersion.

Additionally, the average degree of polymerization of the polyvinyl alcohol may be 200 or less. For example, the average degree of polymerization of the polyvinyl alcohol may be 180 or less or 150 or less, and may be 80 to 200, 90 to 200, or 100 to 200. When the degree of polymerization of polyvinyl alcohol satisfies the above range, dispersibility, storage stability, coating properties, water resistance, and processability can be improved without deteriorating mechanical properties.

When the saponification degree and polymerization degree of polyvinyl alcohol both satisfy the above range, dispersibility, storage stability, coating properties, water resistance, and processability can all be improved. In particular, polyvinyl alcohol with a degree of saponification and polymerization that satisfies the above range has excellent compatibility with PHA, which has the above-mentioned characteristics, and can maximize improvements in dispersibility, storage stability, coating properties, water resistance, and processability. there is.

The biodegradable aqueous dispersion may include 0.01% to 12% by weight of the dispersant based on the total weight of solids. For example, the content of the dispersant is 0.01% by weight to 10% by weight, 0.02% by weight to 8% by weight, 0.05% by weight to 6% by weight, and 0.1% by weight to 5% by weight, based on the total weight of solids of the biodegradable aqueous dispersion. Weight %, 0.2 weight % to 4.5 weight %, 0.3 weight % to 4 weight %, 0.5 weight % to 3.8 weight %, 0.8 weight % to 3.5 weight %, 1 weight % to 3 weight %, 5 weight % to 12 weight % , may be 5.5% by weight to 10.5% by weight or 6.5% by weight to 10% by weight.

According to another embodiment of the present invention, the biodegradable aqueous dispersion may further include one or more additives selected from the group consisting of antibacterial agents, thickeners, waxes, and pH adjusters.

The antibacterial agent may be one or more natural antibacterial agents selected from the group consisting of organic acids, bacteriocins, and calcium agents, colloids, or compounds containing elements such as silver, benzisothiazolinone, polylysine, benzisothiazolinone, and vinegar powder. , chitooligosaccharide, hydrogen peroxide, ethylenediaminetetraacetic acid, potassium sorbate, sorbic acid, propionic acid, potassium propionate, sodium benzoate, 1,2-hexanediol, and 1,2-octanediol.

Additionally, the biodegradable aqueous dispersion may contain 0.01% to 5% by weight of the antibacterial agent based on the total weight of solids. For example, the content of the antibacterial agent is 0.01% to 3% by weight, 0.01% to 2.2% by weight, 0.02% to 1.5% by weight, 0.02% to 1% by weight, based on the total weight of solids of the biodegradable aqueous dispersion. It may be % by weight, 0.03% by weight to 0.8% by weight, or 0.03% by weight to 0.5% by weight.

The thickener refers to a substance that induces a thickening effect through association on the surface of particles present in the dispersion, and includes polysaccharides including inorganic particles, polyurethane-based, hydrophobically modified polyacrylate-based, hydrophobically modified polyether-based and hydrophobic It may be one or more selected from the group consisting of modified cellulose ethers. For example, the inorganic particles are selected from the group consisting of silica, copper, zinc, calcium, aluminum, iron, platinum, palladium, ruthenium, iridium, rhodium, osmium, chromium, cobalt, nickel, manganese, vanadium, molybdenum and gallium. It may be formed from a precursor that is an acetate, chloride, or nitrate of one or more metals. Specifically, when the thickener is a polysaccharide containing silicate-based inorganic particles, especially about 60% by weight of silicate-based inorganic particles, it may be preferable in that storage stability can be further improved, but is limited thereto. no.

Additionally, the biodegradable aqueous dispersion may include 0.01% to 5% by weight of the thickener based on the total weight of solids. For example, the content of the thickener is 0.01% to 3% by weight, 0.01% to 2.2% by weight, 0.02% to 1.5% by weight, 0.02% to 1% by weight, based on the total weight of solids of the biodegradable aqueous dispersion. It may be % by weight, 0.03 wt% to 0.8 wt%, 0.03 wt% to 0.5 wt%, 0.05 wt% to 0.2 wt%, or 0.1 wt% to 0.2 wt%.

The wax may include natural wax, such as mineral wax, vegetable wax, animal wax, and/or mixtures thereof, or synthetic wax. For example, the waxes include crude montan wax, fully refined wax, microcrystalline wax, petroleum jelly, carnauba wax, candelilla wax, beeswax and shellac wax, Fischer-Tropsch synthetic paraffin. , oxidized Fischer-Tropsch paraffin, polyethylene wax, polypropylene wax and its oxidized derivatives, polycaprolactone wax, silicone wax, wax alcohol, polyethylene-vinyl acetate copolymer, polyethylene-acrylic acid copolymer, polyglycol wax, V -Wachs (polyvinyl ether), etc.

Additionally, the biodegradable aqueous dispersion may include 0.01% by weight to 10% by weight of the wax based on the total weight of solids. For example, the content of the wax is 0.01% by weight to 8% by weight, 0.05% by weight to 6% by weight, 0.1% by weight to 5% by weight, and 0.5% by weight to 3.5% by weight based on the total weight of solids of the biodegradable aqueous dispersion. It may be % by weight or 1% to 3% by weight.

The pH adjuster refers to a substance that is added to a solution to adjust pH, and may include both a pH reducer that decreases pH and a pH increase agent that increases pH. Specifically, the pH reducing agent may be a strong acid such as sulfuric acid, hydrochloric acid, or an aqueous ammonium salt solution, and the pH increasing agent may be a basic substance such as ammonia water, sodium hydroxide, lithium hydroxide, or potassium hydroxide, or an aqueous acetate salt solution. , but is not limited to this.

For example, the pH increasing agent may be one or more selected from the group consisting of acetic acid, lactic acid, hydrochloric acid, phosphoric acid, sodium hydroxide, citric acid, malic acid, fumaric acid, potassium phosphate, sodium bicarbonate, and sodium phosphate.

Additionally, the biodegradable aqueous dispersion may include 0.01% to 20% by weight of the pH adjuster based on the total weight of solids. For example, the content of the pH adjuster is 0.01% by weight to 15% by weight, 0.01% by weight to 12% by weight, 0.01% by weight to 10% by weight, 0.01% by weight to 8% by weight, 0.01% by weight to 5% by weight, It may be 0.2% to 4.5% by weight, 0.2% to 4% by weight, or 0.5% to 3% by weight.

생분해성 수계 분산액의 제조 방법Method for preparing biodegradable aqueous dispersion

A method for producing a biodegradable aqueous dispersion according to another embodiment of the present invention includes mixing and stirring polyhydroxyalkanoate and a dispersant to prepare a suspension; filtering, washing and redispersing the suspension; And mixing and stirring the redispersed suspension with a polyol having an average degree of polymerization of 100 to 25,000, wherein the biodegradable aqueous dispersion has a drying rate at 170° C. of 7.0 g/m ² ·s according to Equation 1 above. It is as follows.

The description of the polyhydroxyalkanoate, polyol, and dispersant is the same as above.

Preparing a suspension by mixing and stirring polyhydroxyalkanoate and dispersant

A method for producing a biodegradable aqueous dispersion according to another embodiment of the present invention includes mixing and stirring polyhydroxyalkanoate and a dispersant to prepare a suspension.

According to another embodiment of the present invention, a solvent may be added to the mixture of the PHA and the dispersant. Specifically, the solvent may be water or distilled water, or a mixture of water or distilled water and a hydrophilic solvent. For example, the hydrophilic solvent is methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-amyl alcohol, isoamyl alcohol, sec-amyl alcohol, tert-amyl It may be one or more selected from the group consisting of alcohol, 1-ethyl-1-propanol, 2-methyl-1-butanol, n-hexanol, and cyclohexanol.

Additionally, additives may be additionally added to the mixture of the PHA and the dispersant. The description of the additive is as described above.

The stirring step may be performed at 1,500 rpm to 13,000 rpm for 10 to 70 minutes. For example, the stirring may be performed by centrifugation, homomixer, agitator, or homogenizer, and may be performed at 2,500 rpm to 12,000 rpm, 4,000 rpm to 10,000 rpm, 4,500 rpm to 9,500 rpm, or 5,500 rpm to 5,500 rpm. It may be performed at 9,000 rpm or 6,500 rpm to 8,500 rpm for 15 to 55 minutes, 20 to 50 minutes, or 25 to 40 minutes. When the stirring process conditions satisfy the above range, dispersibility, storage stability, coating properties, and processability can be further improved.

Filtering, washing and redispersing the suspension.

A method for producing a biodegradable aqueous dispersion according to another embodiment of the present invention includes filtering, washing, and redispersing the suspension.

The filtration step may be performed using a filtration material such as paper, woven fabric, non-woven fabric, screen, polymer membrane, or wedge wire, and may be performed using a suction filter, pressure filter, membrane separator, vacuum filter, reduced pressure vacuum filter, industrial filter press, or tube press. , it can be performed using a plate press, gauge press, belt press, screw press, disk press, pressing function press, or centrifuge.

The washing and redispersing steps may be performed using the solvent. Specifically, the solvent used in the washing and redispersing steps may be water or distilled water, or a mixture of water or distilled water and a hydrophilic solvent.

The solids content of the redispersed suspension may be 10% to 60% by weight. Specifically, the suspension can be filtered, washed, and redispersed to adjust the solid content to the above range. For example, the solids content of the redispersed suspension may be 15% to 55% by weight, 20% to 55% by weight, 25% to 50% by weight, 30% to 45% by weight or 35% to 45% by weight. It may be weight percent.

In addition, the redispersion step uses a homogenizer to achieve 10% to 80%, 15% to 75%, 20% to 60%, 20% to 50%, and 40% of the maximum rotation speed per minute (rpm). 10 minutes to 60 minutes, 20 minutes to 60 minutes, 25 minutes to 55 minutes, 25 minutes to 80%, 45% to 70%, 60% to 80%, 65% to 75%, or 60% to 70%. It may be performed for 45 minutes or 25 to 40 minutes.

Mixing and stirring the redispersed suspension with a polyol having an average degree of polymerization of 100 to 25,000.

A method for producing a biodegradable aqueous dispersion according to another embodiment of the present invention includes mixing and stirring the redispersed suspension with a polyol having an average degree of polymerization of 100 to 25,000.

Additives may be additionally added to the mixture of the redispersed suspension and polyol. The description of the additive is as described above.

The stirring step may be performed at 1,500 rpm to 13,000 rpm for 10 to 70 minutes. For example, the stirring may be performed by centrifugation, homomixer, agitator, or homogenizer, and may be performed at 2,500 rpm to 12,000 rpm, 4,000 rpm to 10,000 rpm, 4,500 rpm to 8,500 rpm, or 5,000 rpm to 5,000 rpm. It may be performed at 7,000 rpm for 15 to 55 minutes, 20 to 50 minutes, or 25 to 40 minutes. When the stirring process conditions satisfy the above range, dispersibility, storage stability, coating properties, and processability can be further improved.

생분해성 물품의 제조 방법Method for manufacturing biodegradable articles

A method for producing a biodegradable article according to another embodiment of the present invention includes preparing a biodegradable aqueous dispersion; And forming a biodegradable coating layer on at least one side of the substrate using the biodegradable aqueous dispersion, wherein the biodegradable aqueous dispersion includes polyhydroxyalkanoate, water, and a polyol having an average degree of polymerization of 100 to 25,000. And, the drying rate at 170°C according to Equation 1 above is 7.0 g/m ² ·s or less.

The method for preparing the biodegradable aqueous dispersion is as described above.

The substrate is not limited as long as it is an article that can form a biodegradable coating layer on the surface of the substrate. For example, the substrate may include paper, kraft paper, fabric, non-woven fabric, polyethylene terephthalate (PET) film, polybutylene succinate (PBS), polybutylene adipate (PBA), polybutylene adipate terephthalate ( It may be one or more types selected from the group consisting of polyester-based films such as PBAT), polybutylene succinate terephthalate (PBST), and polyimide (PI) films.

Specifically, it may be preferable that the substrate is a single material in terms of improving the coating properties of the substrate, and the substrate may be paper, kraft paper, fabric, or non-woven fabric, but is not limited thereto. Additionally, when the substrate includes paper or kraft paper, it has better biodegradability than other plastic materials, making it more advantageous to provide eco-friendly packaging materials.

The thickness of the substrate may be 15 μm or more. For example, the thickness of the substrate may be 15 μm or more, 20 μm or more, 50 μm or more, 70 μm or more, 100 μm or more, 130 μm or more, 150 μm or more, 200 μm or more, 300 μm or more, or 500 μm or more. .

Additionally, the basis weight of the substrate may be 30 g/m ² to 500 g/m ² . For example, when the substrate is paper, kraft paper, woven, knitted or non-woven fabric, the basis weight of the substrate is 30 g/m ² to 500 g/m ² , 30 g/m ² to 350 g/m ² , 30 g/m ² to 200 g/m ² , 50 g/m ² to 200 g/m ² , 80 g/m ² to 200 g/m ² , 100 g/m ² to 200 g/m ² , 130 g/ m ² to 190 g/m ² , 150 g/m ² to 185 g/m ² or 120 g/m ² to 320 g/m ² .

Meanwhile, a barrier layer may be disposed on at least one side of the substrate, and an eco-friendly barrier film may be coated on the surface of the substrate to have moisture and/or oxygen barrier properties, or a functional coating layer with antistatic performance or adhesive performance may be applied. Additional information may be included. The functional coating layer may include a primer coating layer and an adhesive coating layer, and these may have commonly used materials and physical properties as long as they do not impair the effect desired in the present invention.

Forming the biodegradable coating layer may include applying and drying the biodegradable aqueous dispersion. Specifically, the step of forming the biodegradable coating layer may be performed by applying the biodegradable aqueous dispersion to at least one surface of the substrate and drying it.

Specifically, the application may be performed at an application amount of 3 g/m ² to 50 g/m ² , and the drying may be performed at 120°C to 200°C for 5 seconds to 10 minutes.

For example, the application amount of the biodegradable aqueous dispersion applied to at least one side of the substrate is 5 g/m ² to 100 g/m ² , 5 g/m ² to 85 g/m ² , and 5 g/m ² to 70 g/m ² , 8 g/m ² to 60 g/m ² , 9 g/m ² to 50 g/m ² , 5 g/m ² to 50 g/m ² , 3 g/m ² to 50 g /m ² , 6 g/m ² to 40 g/m ² , 7 g/m ² to 30 g/m ² , 8 g/m ² to 20 g/m ² or 10 g/m ² to 40 g/m It could be ² . When the application amount satisfies the above range, coating properties, productivity, and processability can be further improved.

Additionally, the application may be performed once to form a single coating layer, or may be performed twice or more to form a plurality of coating layers. The application amount can be adjusted within the above range depending on the desired number of coating layers. Specifically, the application amount may be the total amount applied to a plurality of coating layers.

After the biodegradable coating composition is applied on the substrate, it may be dried at 120°C to 200°C for 5 seconds to 10 minutes. For example, the drying is performed at 125°C to 190°C, 130°C to 185°C, 135°C to 180°C, 140°C to 175°C, or 150°C to 175°C for 5 seconds to 10 minutes, 10 seconds to 8 minutes, 35 It may be performed for seconds to 4 minutes, 40 seconds to 3 minutes, 50 seconds to 2 minutes, 55 seconds to 90 seconds, or 55 seconds to 80 seconds.

The step of forming the biodegradable coating layer can be applied without particular limitations as long as it is a coating process commonly used in the art. For example, the step of forming the biodegradable coating layer may be performed by gravure coating, throat coating, doctor blade coating, spray coating, bar coating, spin coating, or inline coating, but is not limited thereto.

생분해성 물품biodegradable items

Specifically, the biodegradable article may be manufactured according to the method for manufacturing the biodegradable article.

The water resistance of the biodegradable coating layer may be less than 27 g/m ² . For example, the water resistance of the biodegradable coating layer is 25 g/m ² or less, 22 g/m ² or less, 18 g/m ² or less, 17 g/m ² or less, 16 g/m ² or less, or 15 g/m. It may be ² or less.

The water resistance can be measured through a Cobb water absorption test (test time: 10 minutes) according to the TAPPI T441 standard.

The biodegradable article including the biodegradable coating layer may be, but is not limited to, packaging materials, cardboard boxes, shopping bags, disposable tableware, packaging containers, or paper straws.

The above will be explained in more detail by the following examples. However, the following examples are only for illustrating the present invention, and the scope of the examples is not limited to these only.

[실시예][Example]

생분해성 수계 분산액의 제조Preparation of biodegradable aqueous dispersions

실시예 1-1Example 1-1

(1) PHA preparation step

Polyhydroxyalkanoate (PHA) (weight average molecular weight (Mw): 400,000 g/mol, polydispersity index (PDI): 2.6, average particle size: <80 ㎛, 4-hydroxybutyrate (4-HB) Content: 10% by weight, manufacturer: CJ) powder was prepared. The PHA powder was obtained by physical crushing using a homogenizer (product name: homomixer mark2, manufacturer: primix).

(2) Production of suspension

40 parts by weight of the PHA powder, 0.2 parts by weight of 10% concentration of 1,2-benzisothiazolin-3-one antibacterial agent, 7.5 parts by weight of 40% concentration of polyacrylate dispersant, and 55.5 parts by weight of distilled water were placed in a 1 L glass beaker. A suspension was prepared by stirring at 8,000 rpm for 30 minutes using a stirrer (Product name: Homomixer Mark II, Manufacturer: Premix). At this time, the solid content of the suspension was 41.7% by weight.

Afterwards, the suspension was filtered using filter paper and washed with water, then distilled water was additionally added, and the solids of the suspension were redispersed in the water system using a stirrer (product name: Homomixer MarkⅡ, manufacturer: Premix). The content was adjusted to 40% by weight.

(3) Preparation of biodegradable aqueous dispersion

100 parts by weight of the redispersed suspension (solid content 40 parts by weight) contains 0.3 parts by weight of a 1,2-benzisothiazolin-3-one antibacterial agent at a concentration of 10%, and 60% by weight of silicate-based inorganic particles as a thickener. Add 0.1 parts by weight of polysaccharide, 3 parts by weight of 30% concentration carnauba wax, and 5 parts by weight of polyethylene glycol (PEG, average degree of polymerization: 200, manufacturer: Daejung Chemical), and use a stirrer (product name: Homomixer MarkⅡ, manufacturer: Premix). A biodegradable aqueous dispersion with a solid content of 42.5% by weight was prepared by stirring at 6,000 rpm for 30 minutes. At this time, the average particle size of PHA in the biodegradable aqueous dispersion was 2.8 ㎛.

실시예 1-2Example 1-2

A biodegradable aqueous dispersion with a solid content of 41.1% by weight was prepared in the same manner as Example 1-1, except that 2.5 parts by weight of PEG (average degree of polymerization: 400, manufacturer: Daejeong Chemical Gold) was used in step (3). did. At this time, the average particle size of PHA in the biodegradable aqueous dispersion was 2.8 ㎛.

실시예 1-3Example 1-3

A biodegradable aqueous dispersion with a solid content of 40.3% by weight was prepared in the same manner as Example 1-1, except that 1 part by weight of PEG (average degree of polymerization: 20.000, manufacturer: Daejeong Chemical) was used in step (3). did. At this time, the average particle size of PHA in the biodegradable aqueous dispersion was 2.8 ㎛.

실시예 1-4Example 1-4

(1) PHA preparation step

The same PHA as in step (1) of Example 1-1 was prepared.

(2) Production of suspension

40 parts by weight of the PHA powder, 0.2 parts by weight of a benzisothiazolinone antibacterial agent at a 10% concentration, and 10 parts by weight of polyvinyl alcohol (PVA, degree of saponification: 80 mol%, average degree of polymerization: 200, manufacturer: kuraray) at a 10% concentration. and 51.0 parts by weight of distilled water were placed in a 1L glass beaker and stirred at 8,000 rpm for 30 minutes using a stirrer (Product name: Homomixer Mark II, Manufacturer: Premix) to prepare a suspension. At this time, the solid content of the suspension was 40.5% by weight.

(3) Preparation of biodegradable aqueous dispersion

A biodegradable aqueous dispersion with a solid content of 42.5% by weight was prepared in the same manner as step (3) of Example 1-1, except that the redispersed suspension prepared in step (2) was used. At this time, the average particle size of PHA in the biodegradable aqueous dispersion was 2.8 ㎛.

실시예 1-5Examples 1-5

A biodegradable aqueous dispersion with a solid content of 40.3% by weight was prepared in the same manner as Example 1-4, except that 1 part by weight of PEG (average degree of polymerization: 20.000, manufacturer: Daejeong Chemical Gold) was used in step (3). did. At this time, the average particle size of PHA in the biodegradable aqueous dispersion was 3.4 ㎛.

실시예 1-6Example 1-6

A biodegradable aqueous dispersion with a solid content of 41.4% by weight was prepared in the same manner as Example 1-1, except that 3 parts by weight of PEG (average degree of polymerization: 6.000, manufacturer: Daejeong Chemical Gold) was used in step (3). did. At this time, the average particle size of PHA in the biodegradable aqueous dispersion was 3.4 ㎛.

실시예 1-7Example 1-7

(1) PHA preparation step

Polyhydroxyalkanoate (PHA) (weight average molecular weight (Mw): 700,000 g/mol, polydispersity index (PDI): 2.6, average particle size: <60 ㎛, 4-hydroxybutyrate (4-HB) Content: 8.5% by weight, manufacturer: CJ) powder was prepared. The PHA powder was obtained by physical crushing using a homogenizer (product name: homomixer mark2, manufacturer: primix).

(2) Production of suspension

A suspension was prepared in the same manner as step (2) of Example 1-1, except that the PHA powder in step (1) was used.

(3) Preparation of biodegradable aqueous dispersion

Step (3) of Example 1-1, except that 100 parts by weight of the suspension prepared in step (2) and 2.5 parts by weight of polyethylene glycol (PEG, average degree of polymerization: 400, manufacturer: Daejung Chemical) A biodegradable aqueous dispersion with a solid content of 41.1% by weight was prepared in the same manner. At this time, the average particle size of PHA in the biodegradable aqueous dispersion was 2.2 ㎛.

실시예 1-8Examples 1-8

(1) PHA preparation step

The same PHA as in step (1) of Example 1-7 was prepared.

(2) Production of suspension

A suspension was prepared in the same manner as step (2) of Example 1-4, except that the PHA powder in step (1) was used.

(3) Preparation of biodegradable aqueous dispersion

A biodegradable aqueous dispersion with a solid content of 41.1% by weight was prepared in the same manner as step (3) of Example 1-1, except that the suspension prepared in step (2) was used. At this time, the average particle size of PHA in the biodegradable aqueous dispersion was 2.2 ㎛.

비교예 1-1Comparative Example 1-1

A biodegradable aqueous dispersion with a solid content of 39.7% by weight was prepared in the same manner as Example 1-1, except that PEG was not used in step (3). At this time, the average particle size of PHA in the biodegradable aqueous dispersion was 3.7 ㎛.

비교예 1-2Comparative Example 1-2

A biodegradable aqueous dispersion with a solid content of 39.7% by weight was prepared in the same manner as Example 1-4, except that PEG was not used in step (3). At this time, the average particle size of PHA in the biodegradable aqueous dispersion was 3.7 ㎛.

비교예 1-3Comparative Example 1-3

A biodegradable aqueous dispersion with a solid content of 41.4% by weight was prepared in the same manner as Example 1-1, except that 3 parts by weight of glycerin was used instead of PEG in step (3). At this time, the average particle size of PHA in the biodegradable aqueous dispersion was 3.7 ㎛.

비교예 1-4Comparative Example 1-4

A biodegradable aqueous dispersion with a solid content of 41.4% by weight was prepared in the same manner as Example 1-4, except that 3 parts by weight of glycerin was used instead of PEG in step (3). At this time, the average particle size of PHA in the biodegradable aqueous dispersion was 3.7 ㎛.

생분해성 물품의 제조Manufacture of biodegradable articles

실시예 2-1Example 2-1

The biodegradable aqueous dispersion prepared in Example 1-1 was applied on a substrate using a bar coater (manufacturer: RDS) at an application rate of 15 g/m ² and dried at 170°C for 70 seconds. A biodegradable article with a biodegradable coating layer was manufactured. At this time, the substrate was uncoated kraft paper (manufacturer: Hansol Paper) with a basis weight of 180 g/m ² .

실시예 2-2 내지 2-8 및 비교예 2-1 내지 2-4Examples 2-2 to 2-8 and Comparative Examples 2-1 to 2-4

A biodegradable article was prepared in the same manner as Example 2-1, except that the biodegradable aqueous dispersions of Examples 1-2 to 1-8 and Comparative Examples 1-1 to 1-4 were used. At this time, the application amount and drying time of the biodegradable aqueous dispersion were varied as shown in Table 3 below.

[실험예][Experimental example]

실험예 1: 점도Experimental Example 1: Viscosity

For the biodegradable aqueous dispersions prepared in Examples 1-1 to 1-8 and Comparative Examples 1-1 to 1-4, spindle No. 3 was used at a rotation speed of 12 rpm using a DV1MLVTJ0 viscometer (manufacturer: BROOKFIELD) The viscosity was measured for 60 seconds.

실험예 2: pHExperimental Example 2: pH

The pH of the biodegradable aqueous dispersions prepared in Examples 1-1 to 1-8 and Comparative Examples 1-1 to 1-4 was measured using a pH meter (manufacturer: METTLER TOREDO).

실험예 3: 분산 안정성Experimental Example 3: Dispersion stability

The biodegradable aqueous dispersions prepared in Examples 1-1 to 1-8 and Comparative Examples 1-1 to 1-4 were placed in test tubes and left at 50°C for 2 weeks, and then visually dispersed according to the following evaluation criteria. Stability was evaluated.

◎: Phase separation and precipitation do not occur.

○: Slight phase separation occurred, but no precipitation occurred.

△: Some phase separation and precipitation occurred.

×: Phase separation and precipitation clearly occur.

실험예 4: 내수성Experimental Example 4: Water resistance

For the biodegradable articles prepared in Examples 2-1 to 2-8 and Comparative Examples 2-1 to 2-4, a Cobb water absorption test (Cobb water absorption test, test conditions: 25 ml and Water resistance was measured through 10 minutes).

As shown in Table 3, the biodegradable products of Examples 2-1 to 2-8 had very excellent coating properties and water resistance compared to the products of Comparative Examples 2-1 to 2-4.

Specifically, the biodegradable articles of Examples 2-1 to 2-8 include a biodegradable coating layer prepared using the biodegradable aqueous dispersion of Examples 1-1 to 1-8 with excellent pH and viscosity properties, Cobb The water absorption test result was less than 27 g/m ² , showing excellent water resistance. In particular, the biodegradable aqueous dispersions of Examples 1-1 to 1-8 have superior viscosity characteristics and storage stability compared to the dispersions of Comparative Examples 2-1 to 2-4, so even though the drying time is short, the biodegradable aqueous dispersions prepared using them The water resistance of the biodegradable product was excellent. Therefore, the biodegradable aqueous dispersion not only has excellent coating properties, water resistance, and processability, but also when biodegradable products manufactured using it are applied to products that require water resistance, such as food packaging materials for packaging foods with high moisture content. , it can demonstrate excellent characteristics.

On the other hand, the products of Comparative Examples 2-1 to 2-4 include a coating layer prepared using the dispersion of Comparative Examples 1-1 to 1-4, which has poor coating properties due to poor viscosity characteristics and storage stability, and thus has very high water resistance. It wasn't good. In particular, the dispersions of Comparative Examples 1-1 to 1-4 had poor viscosity characteristics and storage stability compared to the biodegradable aqueous dispersions of Examples 1-1 to 1-8, so although the drying time was longer, they were prepared using them. The water resistance of the biodegradable product was very poor.

Claims

polyhydroxyalkanoate;

water; and

Contains a polyol with an average degree of polymerization of 100 to 25,000,

A biodegradable aqueous dispersion with a drying rate at 170°C of 7.0 g/m 2 ·s or less according to Equation 1 below:

[Equation 1]
According to claim 1,

The biodegradable aqueous dispersion is a biodegradable aqueous dispersion containing 0.1% by weight to 15% by weight of the polyol based on the total weight of solids.
According to claim 1,

A biodegradable aqueous dispersion having a drying rate of 6.0 g/m 2 ·s or less at 170°C according to Equation 1 above.
According to claim 1,

The biodegradable aqueous dispersion is polyacrylate-based, polyvinyl alcohol, polyvinylpyrrolidone, methylpolyethylene alkyl ether, sodium dodecylbenzene sulfonate, alkylbenzene sulfonate, nonylphenol ether sulfate, sodium lauryl sulfate, lithium dodecyl ether. A biodegradable aqueous dispersion comprising at least one dispersant selected from the group consisting of syl sulfate, alkyl phosphate, and polypropylene glycol ester.
According to claim 4,

The dispersant includes a polyacrylate type,

A biodegradable aqueous dispersion in which the polyacrylate-based dispersant is an anionic dispersant having a carboxylic acid functional group.
According to claim 4,

The dispersant includes polyvinyl alcohol,

A biodegradable aqueous dispersion wherein the degree of saponification of the polyvinyl alcohol is 80 mol% to 98 mol% and the average degree of polymerization is 200 or less.
According to claim 4,

The biodegradable aqueous dispersion is a biodegradable aqueous dispersion containing 0.01% to 12% by weight of the dispersant based on the total weight of solids.
According to claim 1,

The polyhydroxyalkanoate is 3-hydroxybutyrate (3-HB), 4-hydroxybutyrate (4-HB), 3-hydroxypropionate (3-HP), and 3-hydroxyhexanoate. (3-HH), 3-hydroxyvalerate (3-HV), 4-hydroxyvalerate (4-HV), 5-hydroxyvalerate (5-HV) and 6-hydroxyhexanoate ( A biodegradable aqueous dispersion, which is a copolymerized polyhydroxyalkanoate containing at least one repeating unit selected from the group consisting of 6-HH).
According to claim 8,

The polyhydroxyalkanoate is a copolymerized polyhydroxyalkanoate containing a 4-hydroxybutyrate (4-HB) repeating unit and a 3-hydroxybutyrate (3-HB) repeating unit, wherein the 4-hydroxyalkanoate A biodegradable aqueous dispersion comprising 0.1% to 60% by weight of butyrate (4-HB) repeating unit.
According to claim 1,

The biodegradable aqueous dispersion has a viscosity of 105 mPa·s to 2,500 mPa·s and a pH of greater than 7.
According to claim 1,

A biodegradable aqueous dispersion, wherein the average particle size of the polyhydroxyalkanoate in the biodegradable aqueous dispersion is 0.5 ㎛ to 5 ㎛.
According to claim 1,

A biodegradable aqueous dispersion, wherein the solid content of the biodegradable aqueous dispersion is 10% to 60% by weight.
Preparing a biodegradable aqueous dispersion; and

Comprising the step of forming a biodegradable coating layer on at least one side of the substrate using the biodegradable aqueous dispersion,

The biodegradable aqueous dispersion includes polyhydroxyalkanoate, water, and a polyol with an average degree of polymerization of 100 to 25,000, and has a drying rate at 170 ° C. of 7.0 g/m 2 ·s or less according to Equation 1 below. Method of manufacturing sex articles:

[Equation 1]
According to claim 13,

Forming the biodegradable coating layer includes applying and drying the biodegradable aqueous dispersion,

The application is carried out at an application rate of 3 g/m 2 to 50 g/m 2 ,

A method for producing a biodegradable article, wherein the drying is performed at 120°C to 200°C for 5 seconds to 10 minutes.
write; And a biodegradable coating layer on at least one side of the substrate,

The biodegradable coating layer is formed using a biodegradable aqueous dispersion,

The biodegradable aqueous dispersion includes polyhydroxyalkanoate, water, and a polyol with an average degree of polymerization of 100 to 25,000, and has a drying rate at 170° C. of 7.0 g/m 2 ·s or less according to the following formula 1. article:

[Equation 1]
According to claim 15,

A biodegradable article, wherein the water resistance of the biodegradable coating layer is less than 27 g/m 2 .