KR20210111187A - Preparation method of polyhydroxyalkanoates dispersion - Google Patents

Abstract

The present invention relates to polyhydroxyalkanoates (PHA) dispersions and a method for preparing the same. Specifically, according to one embodiment of the present invention, a method for preparing a polyhydroxyalkanoates (PHA) dispersion comprises a step of dispersing polyhydroxyalkanoates (PHA) in a solvent using a particle dispersion method, a melt dispersion method, or a solvent extraction method, thereby effectively preparing polyhydroxyalkanoates (PHA) dispersion having excellent dispersibility, dispersion stability, and processability.

Description

PREPARATION METHOD OF POLYHYDROXYALKANOATES DISPERSION

The present invention relates to a process for preparing a polyhydroxyalkanoate (PHA) dispersion.

Recently, as concerns about environmental problems increase, research on the treatment of various household wastes and their recycling is being actively conducted. Specifically, inexpensive polymer materials with excellent processability and other properties are widely used to manufacture various products such as paper, films, fibers, packaging materials, bottles, containers, etc. Substances can be released, and it takes hundreds of years depending on the type to be completely decomposed in nature.

Therefore, it is possible to improve the eco-friendliness by decomposing in a short time, while improving the mechanical properties, oil resistance, water resistance and processability to increase the lifespan of the product itself, thereby reducing the amount of waste or improving recyclability. research is ongoing.

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

On the other hand, 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 or water resistance and oil resistance. In order to improve these properties, a process of forming a coating layer on the surface of the product may be used, but there is a problem in that biodegradability or recyclability is reduced due to the coating layer. Therefore, there is a need to develop an environmentally friendly, biodegradable dispersion having excellent biodegradability and biocompatibility and excellent dispersibility, coating property and processability, and a method for effectively preparing the same.

Korean Patent Publication No. 2012-0103158

Accordingly, an object of the present invention is to provide a method for preparing a polyhydroxyalkanoate (PHA) dispersion that is environmentally friendly and can improve dispersibility, dispersion stability and processability due to excellent biodegradability and biocompatibility.

A method for preparing a polyhydroxyalkanoate (PHA) dispersion according to another embodiment of the present invention comprises dispersing the polyhydroxyalkanoate (PHA) in a solvent using a particle dispersion method, a melt dispersion method, or a solvent extraction method. includes steps.

The method for preparing a polyhydroxyalkanoate (PHA) dispersion according to an embodiment of the present invention comprises dispersing polyhydroxyalkanoate (PHA) in a solvent using a particle dispersion method, a melt dispersion method, or a solvent extraction method. By including, it is possible to effectively prepare a polyhydroxyalkanoate (PHA) dispersion having excellent dispersibility, dispersion stability and processability.

1 is a photograph of PHA prepared in step (1) of Examples 1-3.
2 is a photograph of the PHA dispersion prepared in Examples 1 to 3.
3 shows a biodegradable article according to an embodiment of the present invention.
4 shows a biodegradable article according to another embodiment of the present invention.

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

In the present specification, when a part "includes" a certain component, this means that other components may be further included, rather than excluding other components, unless otherwise stated.

All numbers and expressions indicating amounts of ingredients, reaction conditions, etc. described herein are to be understood as being modified by the term "about" in all cases unless otherwise specified.

In this specification, a component described as being formed above or below another component means that a component is formed directly above or below another component or indirectly through another component. include

In this specification, terms such as first, second, primary, secondary, etc. are used to describe various components, and the components are not limited by the terms. The above terms are used only for the purpose of distinguishing one component from another.

In this specification, the standards for "one side" / "other surface" or "upper" / "lower" of each component are described based on the drawings, and these terms are only terms for distinguishing the components, and actual application may be interchangeable.

In addition, the size of each component in the drawings may be exaggerated for explanation, and does not mean the size actually applied. Also, like reference numerals refer to like elements throughout.

Polyhydroxyalkanoate (PHA) dispersion

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

The solid content of the polyhydroxyalkanoate (PHA) dispersion may be 10 wt% to 60 wt%. For example, the solids content of the PHA dispersion may be 10 wt% to 60 wt%, 15 wt% to 55 wt%, 20 wt% to 55 wt%, 25 wt% to 50 wt%, 30 wt% to 45 wt% or 35% to 45% by weight.

The viscosity of the polyhydroxyalkanoate (PHA) dispersion may be 100 mPa·s to 1,000 mPa·s. For example, the viscosity of the PHA dispersion may be 100 mPa·s to 1,000 mPa·s, 100 mPa·s to 900 mPa·s, 100 mPa·s to 650 mPa·s, 100 mPa·s to 650 mPa·s, 105 mPa·s to 500 mPa·s, 105 mPa·s to 400 mPa·s, 110 mPa·s to 350 mPa·s or 115 mPa·s to 315 mPa·s.

The haze of the polyhydroxyalkanoate (PHA) dispersion may be 5% to 400%. For example, the haze of the PHA dispersion may be between 5% and 400%, between 15% and 390%, between 40% and 385%, between 50% and 360%, between 80% and 360%, between 100% and 355%, between 120% and 350%. %, 140% to 345%, 150% to 340%, 160% to 340%, 180% to 340%, 200% to 340%, 215% to 340%, 225% to 340%, 233% to 338%, 235% to 335%, 236% to 331%, 250% to 340%, 280% to 335%, 295% to 330%, 300% to 330%, 300% to 400%, 350% to 400%, 5% to 300%, 10% to 250%, 15% to 200%, 20% to 180%, 35% to 150%, or 50% to 130%.

In addition, L* of the polyhydroxyalkanoate (PHA) dispersion may be 40 or more, a* may be less than 0.44, and b* may be 6 or less. For example, L* of the PHA dispersion may be 40 or more, 42 or more, 45 or more, 48 or more, 40 to 60, 42 to 58, 45 to 55 or 48 to 55, and a* is less than 0.44, 0.43 or less. , 0.42 or less, 0.4 or less, 0.01 or more and less than 0.44, 0.05 to 0.42, 0.08 to 0.4, 0.1 to 0.4 or 0.1 to 0.38, b* is 6 or less, 5.8 or less, 5.6 or less, 5.5 or less, 3 to 6 , 3.3 to 5.8, 3.5 to 5.6, 3.7 to 5.6, 4 to 6, 4.2 to 5.8 or 4.4 to 5.5.

The L*, the a*, and the b* are the color systems established by the International Standard Color Measuring Organization (CIE (Commission International d'Eclairage)). , b (complementary colors from yellow to blue) to express colors, and can be measured using a spectrophotometer CM-5 (manufacturer: Konica Minolta).

The yellowness (Y.I.) of the polyhydroxyalkanoate (PHA) dispersion is measured according to ASTME313 and may be 30 or less. For example, the yellowness (YI) of the PHA dispersion may be 30 or less, 25 or less, 23 or less, 20 or less, 18 or less, 15 or less, 14 or less, 13 or less, 12.95 or less, or 12.8 or less, 3 to 30, 4 to 28, 5 to 25, 6 to 20, 6 to 13, 7 to 18, 8 to 13, 3 to 15, 3 to 10, 5 to 30, 10 to 30, 10 to 15, 13 to 30, 15 to 28 or 20 to 30.

When the haze, color characteristics such as L*, a* and b*, and yellowness of the PHA dispersion satisfy the above ranges, it has excellent color characteristics and can improve the anti-yellowing effect.

In addition, the zeta potential of the polyhydroxyalkanoate (PHA) dispersion may be -10 mV or less. For example, the zeta potential of the PHA dispersion may be -10 mV or less, -15 mV or less, -20 mV or less, -25 mV or less, or -30 mV or less, and may be -150 mV or more, -125 mV or more, -100 mV or less. or higher or -80 mV or higher. When the zeta potential of the PHA dispersion satisfies the above range, the dispersion stability between particles in the PHA dispersion and the dispersibility of the high content PHA dispersion can be further improved.

Zeta potential (or electrokinetic potential) refers to the difference in electrical potential between the charge of the ions surrounding the particle and the charge of the dispersion. Specifically, there are two types of the liquid layer existing around the particles. It is an outer region (Defuse) in which ions are relatively weakly coupled to an inner region (Stem layer: electron layer) that forms a strong boundary. The Defuse is the region within the theoretical boundary where ions and particles stably exist. For example, when a particle moves, the ions in the inner region move within a predetermined boundary. On the other hand, ions existing outside the predetermined boundary move independently like a huge dispersant regardless of the particles. The potential at this boundary is the zeta potential.

The zeta potential may be measured by a ZetaPlus Zeta Potential Analyzer (manufactured by: Brookhaven Instruments), a zeta sizer (manufactured by: melbourne instrument), or the like, but is not limited thereto.

The pH of the polyhydroxyalkanoate (PHA) dispersion may be 3 to 11 or 4 to 10.

In addition, the light transmittance of the polyhydroxyalkanoate (PHA) dispersion may be 5% to 99%. For example, the light transmittance of the PHA dispersion may be the light transmittance of the biodegradable coating layer formed from the PHA dispersion, 5% to 99%, 10% to 99%, 10% to 90%, 15% to 95%, 20% to 90%, 25% to 85%.

Polyhydroxyalkanoate (PHA)

Polyhydroxyalkanoate (PHA) is derived from conventional petroleum, polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS), polybutylene succinate terephthalate (PBST), polybutylene It has properties similar to synthetic polymers such as succinate adipate (PBSA), shows complete biodegradability, and has excellent biocompatibility.

Specifically, the PHA is a thermoplastic natural polyester polymer that accumulates in microbial cells. Since it is a biodegradable material, it can be composted and finally decomposed into carbon dioxide, water and organic waste without generating toxic waste. In particular, since the PHA can be biodegradable in soil and sea, a dispersion containing the same and a biodegradable article manufactured using the same may have environmentally friendly properties. Accordingly, the dispersion containing the PHA and the biodegradable article manufactured using the dispersion have excellent biodegradability and are environmentally friendly, and thus have a great advantage in that they can be utilized in various fields.

Since the polyhydroxyalkanoate (PHA) dispersion according to an embodiment of the present invention contains polyhydroxyalkanoate (PHA) particles, biodegradability can be improved without deterioration of mechanical properties.

The PHA may be formed by polymerizing one or more repeating monomer units in living cells using an enzyme catalyst.

The PHA may be a polyhydroxyalkanoate (PHA) copolymer (hereinafter referred to as a PHA copolymer), specifically, a copolymer in which different repeating units are randomly distributed in a polymer chain. .

Examples of the repeating unit that can be incorporated into the PHA include 2-hydroxybutyrate, lactic acid, glycolic acid, 3-hydroxybutyrate (hereinafter referred to as 3-HB), 3-hydroxypropionate (hereinafter, 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-HHep), 3-hydroxyoctanoate (hereinafter referred to as 3-HO), 3-hydroxynonanoate (hereinafter referred to as 3-HN), 3-hydroxy Roxydecanoate (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) may be, and the PHA may contain one or more repeating units selected from them.

Specifically, the PHA is 3-HB, 4-HB, 3-HP, 3-HH. It may include 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 include a 4-HB repeating unit. That is, the PHA may be a PHA copolymer including a 4-HB repeating unit.

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

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

According to an embodiment of the present invention, it is important to control the content of the 4-HB repeating unit included in the PHA copolymer.

Specifically, in order to implement the physical properties desired in the present invention, in particular, to enhance biodegradability in soil and sea, dispersibility, dispersion stability, storage stability, coating property, water resistance, processability, productivity, etc. without deterioration of mechanical properties In order to realize excellent physical properties, it is very important to control the content of the 4-HB repeating unit included in the PHA copolymer.

More specifically, the PHA copolymer may include 0.1 wt% to 60 wt% of the 4-HB repeating unit based on the total weight of the PHA copolymer. For example, the content of the 4-HB repeating unit may be 0.1 wt% to 60 wt%, 0.1 to 55 wt%, 0.5 to 60 wt%, 0.5 to 55 wt%, 1 wt% based on the total weight of the PHA copolymer % to 60 wt%, 1 wt% to 55 wt%, 1 wt% to 50 wt%, 2 wt% to 55 wt%, 3 wt% to 55 wt%, 3 wt% to 50 wt%, 5 wt% to 55 wt%, 5 wt% to 50 wt%, 10 wt% to 55 wt%, 10 wt% to 50 wt%, 1 wt% to 40 wt%, 1 wt% to 30 wt%, 1 wt% to 29 wt% % 1% to 25%, 1% to 24%, 2% to 20%, 2% to 23%, 3% to 20%, 3% to 15%, 4 wt% to 18 wt%, 5 wt% to 15 wt%, 8 wt% to 12 wt%, 9 wt% to 12 wt%, 15 wt% to 55 wt%, 15 wt% to 50 wt%, 20 wt% to 55 wt%, 20 wt% to 50 wt%, 25 wt% to 55 wt%, 25 wt% to 50 wt%, 35 wt% to 60 wt%, 40 wt% to 55 wt% or 45 wt% to 55 wt% % by weight.

When the content of 4-HB repeating unit satisfies the above range, biodegradability in soil and sea is improved, and properties such as dispersibility, dispersion stability, storage stability, coating property, processability and productivity are further improved without deterioration of mechanical properties. can be improved

According to an embodiment of the present invention, the PHA may be a PHA copolymer with controlled crystallinity. Specifically, the PHA may include at least one 4-HB repeating unit, and the crystallinity of the PHA may be controlled by controlling the content of the 4-HB repeating unit.

In addition, 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-HH) ) may be a polyhydroxyalkanoate (PHA) copolymer comprising one or more repeating units selected from the group consisting of.

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

For example, the PHA copolymer contains 20 wt% or more, 35 wt% or more, 40 wt% or more, or 50 wt% or more, 60 wt% or more, 70 wt% or more of 3-HB repeating units based on the total weight of the PHA copolymer It may be included in weight % or more or 75 wt% or more, 99 wt% or less, 98 wt% or less, 97 wt% or less, 96 wt% or less, 95 wt% or less, 93 wt% or less, 91 wt% or less, 90 wt% or less Weight % or less, 80 wt% or less, 70 wt% or less, 60 wt% or less, or 55 wt% or less may be included.

The crystallinity-controlled PHA may be one in which crystallinity and amorphous properties are adjusted by increasing molecular structure irregularities, and specifically, the type or ratio of monomers or the type or content of isomers may be adjusted.

According to an embodiment of the present invention, the PHA may include two or more kinds of PHAs having different crystallinities. Specifically, the PHA may be prepared by mixing two or more PHAs having different crystallinities to have the content of the 4-HB repeating unit in the specific range.

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 a 4-HB repeating unit in an amount of 0.1 wt% to 30 wt%. For example, the first PHA may contain 0.1 wt% to 30 wt%, 0.5 wt% to 30 wt%, 1 wt% to 30 wt%, 3 wt% to 30 wt%, 1 wt% of the 4-HB repeating unit. to 28 wt%, 1 wt% to 25 wt%, 1 wt% to 24 wt%, 1 wt% to 15 wt%, 2 wt% to 25 wt%, 3 wt% to 25 wt%, 3 wt% to 24 wt% Weight %, 5% to 24% by weight, 7% to 20% by weight, 10% to 20% by weight, 15% to 25% by weight or 15% to 24% by weight may be included.

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. to 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) is 105 °C to 165 °C, 110 °C to 160 °C, 115°C to 155°C or 120°C to 150°C.

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.

In addition, the PHA may include a second PHA, which is an atypical PHA with controlled crystallinity.

The second PHA is an amorphous PHA with controlled crystallinity (hereinafter referred to as aPHA), and contains 15 to 60% by weight, 15 to 55% by weight, 20 to 55% by weight of the 4-HB repeating unit. %, 25% to 55%, 30% to 55%, 35% to 55%, 20% to 50%, 25% to 50%, 30% to 50%, 35 wt% to 50 wt% or 20 wt% to 40 wt% may be included.

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.

In addition, 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 weight 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 have.

The first PHA and the second PHA may be distinguished according to 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 may have at least one characteristic. Specifically, the first PHA and the second PHA may be distinguished according to the content of the 4-HB repeating unit, the glass transition temperature (Tg), the crystallization temperature (Tg), the melting temperature (Tm), and the like.

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

Specifically, since the PHA includes the first PHA that is a semi-crystalline PHA, or includes both the first PHA that is a semi-crystalline PHA and the second PHA that is an amorphous PHA, more specifically, the content of the first PHA and the second PHA By controlling the dispersibility, dispersion stability, storage stability, coatability and processability can be further improved.

In addition, the glass transition temperature (Tg) of the PHA is -45 ℃ to 80 ℃, -35 ℃ to 80 ℃, -30 ℃ to 80 ℃, -25 ℃ to 75 ℃, -20 ℃ to 70 ℃, -35 ℃ to 5 °C, -25 °C to 5 °C, -35 °C to 0 °C, -25 °C to 0 °C, -30 °C to -10 °C, -35 °C to -15 °C, -35 °C to -20 °C, - 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 ℃ to 110 ℃.

The melting temperature (Tm) of the PHA is not measured, or 100°C to 170°C, 105°C to 170°C, 105°C to 165°C, 110°C to 160°C, 115°C to 155°C, 110°C to 150°C, 120 It may be from ℃ to 150 ℃ or from 120 ℃ to 140 ℃.

In addition, 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 1,200,000 g/mol, 50,000 g/mol to 1,000,000 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 1,000,000 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, 200,000 g/mol to 700,000 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 800,000 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 1,050,000 g/mol, 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 as measured by Differential Scanning Calorimeter (DSC) may be 90% or less. For example, the crystallinity of the PHA may be measured by differential scanning calorimetry, and may be 90% or less, 85% or less, 80% or less, 75% or less, or 70% or less.

According to one embodiment of the present invention, the PHA dispersion comprises PHA particles. Specifically, the PHA dispersion may include PHA particles obtained from the PHA.

The average particle diameter of the PHA particles may be 0.5 μm to 5 μm. For example, the average particle diameter of the PHA particles may be 0.5 μm to 5 μm, 0.5 μm to 4.5 μm, 0.7 μm to 4 μm, 1 μm to 3.5 μm, or 1.2 μm to 3.5 μm.

In addition, the particle size deviation of the PHA particles may be within ±0.3 μm. For example, the particle size deviation of the PHA particles may be within ±0.2 μm, within ±0.15 μm, within ±0.1 μm, or within ±0.05 μm.

The average particle diameter and particle size deviation of the PHA particles may be measured with a nano particle size analyzer (ex. Zetasizer Nano ZS). Specifically, for the PHA particles, the average particle diameter and particle size deviation were measured through 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 value of the peak derived through the polydispersity index (PDI) in the confidence interval of 0.5 was measured as the particle size.

The polydispersity index (PDI) of the PHA may be less than 3. For example, the polydispersity index of the PHA may be less than 3, 2.8 or less, 2.5 or less, 2.1 or less, or 2 or less.

When the average particle diameter, particle size deviation, and polydispersity index of PHA satisfy the above ranges, dispersibility, dispersion stability, storage stability, coating property and processability can be further improved.

In addition, the PHA may be obtained by cell disruption using a mechanical method or a physical method, or may be obtained by cell disruption using a non-mechanical method or a chemical method. . Specifically, since the PHA is a thermoplastic natural polyester polymer that accumulates in microbial cells and has a relatively large average particle diameter, it may be obtained through a crushing process to improve dispersibility, coating property and processability.

According to another embodiment of the present invention, the PHA dispersion may further include a biodegradable polymer.

Specifically, the biodegradable polymer is polylactic acid (PLA), polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS), thermoplastic starch (TPS), polybutylene succinate terephthalate (PBST) , polyethylene terephthalate (PET), polybutylene succinate adipate (PBSA), polybutylene adipate (PBA), polypropylene (PP), polyethylene (PE) and polycaprolactone (PCL) selected from the group consisting of It may include one or more types. Since the PHA dispersion further includes the biodegradable polymer, it may be more advantageous to control properties such as mechanical properties.

According to another embodiment of the present invention, the PHA dispersion may include a surfactant. When the PHA dispersion contains a surfactant, dispersibility, dispersion stability, storage stability, coatability and processability can be further improved.

Specifically, the surfactant is one selected from the group consisting of cationic surfactants, anionic surfactants, phosphoric acid-based surfactants, fatty acid-based surfactants, acrylic surfactants, urethane-based surfactants, epoxy-based surfactants, and nonionic surfactants It may be more than one species, and may be a polymer surfactant including one or more selected from the group consisting of carboxylic acids, amines, isocyanates, and derivatives thereof.

For example, the surfactant may include polyvinyl alcohol, sodium dodecylbenzene sulfonate, polyvinyl pyrrolidone, methyl polyethylene alkyl ether, alkylbenzene sulfonate, nonylphenol ether sulfate, sodium lauryl sulfate, lithium dodecyl sulfate, It may be at least one selected from the group consisting of alkyl phosphates, glyceryl esters and polypropylene glycol esters.

The PHA dispersion may include 0.01 wt% to 30 wt% of the surfactant relative to the total weight of the PHA dispersion based on solid content. For example, the content of the surfactant may be 0.01 wt% to 30 wt%, 0.05 wt% to 25 wt%, 0.05 wt% to 20 wt%, 0.1 wt% to 15 wt%, based on the solid content, based on the total weight of the PHA dispersion. , 0.1 wt% to 10 wt%, 0.1 wt% to 5 wt%, 0.01 wt% to 5 wt%, 0.05 wt% to 4 wt%, 0.1 wt% to 5 wt%, 1 wt% to 5 wt%, 1.5 weight % to 5 weight %, 0.1 weight % to 3 weight % or 0.1 weight % to 2.8 weight %.

The PHA dispersion has excellent dispersibility, dispersion stability, storage stability, coatability and processability despite including a small amount of surfactant compared to the prior art.

The PHA dispersion may further include at least one additive selected from the group consisting of a rheology control agent, an antioxidant, a stabilizer, an antibacterial agent, an antifoaming agent, an antiseptic agent, and a pH adjusting agent.

The rheology control agent may be at least one selected from the group consisting of gums, clay minerals, cellulose derivatives, cellulose-based regulators, acrylic-based regulators, and urethane-based regulators. For example, the rheology modifier may be one type of gum, a clay mineral, or a cellulosic modifier, or a mixture of two such as gum and a clay mineral or a gum and a cellulosic modifier.

The gum may be at least one selected from the group consisting of xanthan gum, guar gum, gellan gum, locust gum, xanthan gum, gum arabic, carrageenan, karaya gum, ghati gum, tara gum, tamarind gum and tragacanth gum. . The clay mineral may be at least one selected from the group consisting of bentonite, smectite, eterpulgite, montmorillonite, kaolinite, sericite, and illite.

The cellulose derivative may be at least one selected from the group consisting of casein, sodium caseinate and sodium alginate. The cellulose-based regulator may be at least one selected from the group consisting of methyl cellulose, hydroxypropyl cellulose and methyl hydroxypropyl cellulose.

In addition, the rheology modifier may have a branched, straight, plate, irregular, spherical or rod-shaped shape. By having the rheology control agent as described above, it is possible to further improve coating properties, processability and productivity.

The rheology modifier is 0.01 wt% to 20 wt%, 0.01 wt% to 15 wt%, 0.01 wt% to 12 wt%, 0.01 wt% to 10 wt%, 0.01 wt% based on the total weight of the PHA dispersion on a solids basis to 8 wt%, 0.01 wt% to 5 wt%, 0.01 wt% to 4 wt%, 0.01 wt% to 3 wt%, 0.02 wt% to 2 wt%, 0.02 wt% to 1.5 wt% or 0.03 wt% to 1 wt% It may be included in weight %.

The antioxidant is an additive to prevent decomposition by ozone or oxygen, or to prevent oxidation during storage, and to prevent deterioration of physical properties. As long as the effect of the present invention is not impaired, commonly used antioxidants can be used.

Specifically, the antioxidant may include at least one selected from the group consisting of a hindered phenol-based antioxidant and a phosphite-based (phosphorus) antioxidant.

For example, the hindered phenolic antioxidant is 4,4'-methylene-bis(2,6-di-t-butylphenol), octadecyl-3-(3,5-di-t-butyl-4) -hydroxyphenyl)propionate, pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate) and 3,9-bis[2-[3- from the group consisting of (3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane It may include at least one selected type.

In addition, the phosphite-based (phosphorus-based) antioxidant is tris-(2,4-di-t-butylphenyl)phosphite, bis-(2,4-di-t-butylphenyl)pentaerythritol-diphosphite, Bis-(2,6-di-t-butyl-4-methylphenyl)pentaerythritol-diphosphite, distearyl-pentaerythritol-diphosphite, [bis(2,4-di-t-butyl-5- Methylphenoxy)phosphino]biphenyl and N,N-bis[2-[[2,4,8,10-tetrakis(1,1-dimethylethyl)dibenzo[d,f][1,3, 2] It may include at least one selected from the group consisting of deoxyphosphepin-6-yl]oxy]-ethyl]ethanamine.

The antioxidant is 0.01 wt% to 20 wt%, 0.01 wt% to 15 wt%, 0.01 wt% to 12 wt%, 0.01 wt% to 10 wt%, 0.01 wt% to the total weight of the PHA dispersion on a solids basis 8 wt%, 0.01 wt% to 5 wt%, 0.2 wt% to 4.5 wt%, 0.2 wt% to 4 wt% or 0.5 wt% to 3 wt% may be included.

The stabilizer is an additive to protect from oxidation and heat, and to prevent color change. As long as the stabilizer does not impair the effects of the present invention, a commonly used stabilizer may be used.

Specifically, the stabilizer may be at least one selected from the group consisting of trimethyl phosphate, triphenyl phosphate, trimethyl phosphine, phosphoric acid and phosphorous acid.

The stabilizer is 0.01 wt% to 20 wt%, 0.01 wt% to 15 wt%, 0.01 wt% to 12 wt%, 0.01 wt% to 10 wt%, 0.01 wt% to the total weight of the PHA dispersion on a solids basis 8 wt%, 0.01 wt% to 5 wt%, 0.2 wt% to 4.5 wt%, 0.2 wt% to 4 wt% or 0.5 wt% to 3 wt% may be included.

The antibacterial agent may be at least one natural antibacterial agent selected from the group consisting of organic acids, bacteriocins and calcium agents or a compound containing an element such as colloid or silver, polylysine, benzisothiazolinone, vinegar powder, chitooligosaccharide, hydrogen peroxide, It may be at least one selected from the group consisting of ethylenediaminetetraacetic acid, potassium sorbate, sorbic acid, propionic acid, potassium propionate, sodium benzoate, 1,2-hexanediol, and 1,2-octanediol.

The antimicrobial agent is 0.01 wt% to 5 wt%, 0.01 wt% to 3 wt%, 0.01 wt% to 1 wt%, 0.1 wt% to 1 wt%, 0.2 wt% based on the total weight of the biodegradable coating composition on a solids basis to 1% by weight or 0.3% to 1% by weight.

In addition, the antifoaming agent is an additive for preventing or reducing foaming. As long as the anti-foaming agent does not impair the effects of the present invention, a conventionally used anti-foaming agent may be used.

For example, the anti-foaming agent may be at least one selected from the group consisting of alcohol-based anti-foaming agents, polar compound-based anti-foaming agents, inorganic particle-based anti-foaming agents and silicone-based anti-foaming agents, ethyl alcohol, 2-ethylhexanol, polysiloxane, dimethyl polysiloxane, silicone paste , silicone emulsion, silicone treatment powder, fluorosilicone, distearic acid, ethylene glycol, and may be at least one selected from the group consisting of natural wax.

The antifoaming agent is 0.0001% to 5% by weight, 0.0001% to 3% by weight, 0.0001% to 1% by weight, 0.001% to 1% by weight or 0.001% to 0.5% by weight based on the total weight of the PHA dispersion on a solids basis It may be included in weight %.

In addition, the preservative is at least one natural selected from the group consisting of hydroxyacetophenone, centella asiatica extract, 1,2-hexanediol and 1,3-butanediol extracted from camprina oak tree. It may be a preservative, and may be at least one preservative selected from the group consisting of benzisothiazolin-3-one and potassium benzoate, but is not limited thereto.

The preservative is 0.01% to 20% by weight, 0.01% to 15% by weight, 0.01% to 12% by weight, 0.01% to 10% by weight, 0.01% to 8% by weight, based on the solids content, based on the total weight of the PHA dispersion Weight %, 0.01% to 5% by weight, 0.2% to 4.5% by weight, 0.2% to 4% by weight or 0.5% to 3% by weight may be included.

In addition, the pH adjusting agent refers to a material that is added to a solution to adjust the pH, and may include both a pH reducing agent for decreasing pH and a pH increasing agent for increasing pH. Specifically, the pH reducing agent may be a strong acid material such as sulfuric acid or hydrochloric acid, or an aqueous ammonium salt solution, and the pH increasing agent may be a basic material such as aqueous ammonia, sodium hydroxide, lithium hydroxide, potassium hydroxide, or the like, or an aqueous acetate salt solution. , but is not limited thereto.

For example, the pH increasing agent may be at least one 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 hydrogen carbonate and sodium phosphate.

The pH adjuster is 0.01 wt% to 20 wt%, 0.01 wt% to 15 wt%, 0.01 wt% to 12 wt%, 0.01 wt% to 10 wt%, 0.01 wt% to the total weight of the PHA dispersion on a solids basis 8 wt%, 0.01 wt% to 5 wt%, 0.2 wt% to 4.5 wt%, 0.2 wt% to 4 wt% or 0.5 wt% to 3 wt% may be included.

Method for preparing polyhydroxyalkanoate (PHA) dispersion

A method for preparing a polyhydroxyalkanoate (PHA) dispersion according to another embodiment of the present invention comprises dispersing the polyhydroxyalkanoate (PHA) in a solvent using a particle dispersion method, a melt dispersion method, or a solvent extraction method. includes steps.

The polyhydroxyalkanoate (PHA) may be obtained by cell disruption using a mechanical or physical method. Alternatively, the polyhydroxyalkanoate (PHA) may be obtained by cell disruption using a non-mechanical or chemical method.

In the case of cell disruption using the mechanical or physical method, since the average particle diameter of the crushed PHA is larger than that of the cell disruption using the non-mechanical or chemical method, the dispersibility is lower. However, the method for preparing a PHA dispersion according to the present invention may have excellent dispersibility even when cell disruption using a mechanical or physical method is performed.

In addition, the method for preparing the polyhydroxyalkanoate (PHA) dispersion is 1 selected from the group consisting of an agitator, a homogenizer, a high pressure homogenizer, a high pressure disperser (microfluidizer) and a colloid mill. It may be carried out by more than one type of apparatus, or by one or more methods selected from the group consisting of high shear force, ultrasonic emulsification (ultra sonicator), and membrane emulsification.

particle dispersion method

Another method for preparing a PHA dispersion according to an embodiment of the present invention comprises the steps of (1) preparing the polyhydroxyalkanoate (PHA) obtained by cell disruption using a physical or chemical method; and (2) dispersing the polyhydroxyalkanoate (PHA) in a solvent using a particle dispersing method.

First, the polyhydroxyalkanoate (PHA) obtained by cell disruption using a physical or chemical method may be prepared (step (1)).

The description of the cell disruption and PHA is the same as described above.

In addition, the PHA prepared in step (1) may be in the form of fine particles. Specifically, the PHA obtained by cell disruption using a physical or chemical method in step (1) may be a powder in the form of fine particles.

Thereafter, the polyhydroxyalkanoate (PHA) may be dispersed in a solvent using a particle dispersing method (step (2)).

Specifically, step (2) may include adding the surfactant to the PHA prepared in step (1). For example, in step (2), 0.01 wt% to 30 wt%, 0.05 wt% to 25 wt%, 0.05 wt% to 20 wt%, 0.1 wt% to 15 wt%, 0.1 wt% to 10 wt%, 0.1 wt% to 5 wt%, 0.01 wt% to 5 wt%, 0.05 wt% to 4 wt%, 0.1 wt% to 5 wt%, 1 wt% to 5 wt% %, 1.5 wt% to 5 wt%, 0.1 wt% to 3 wt%, or 0.1 wt% to 2.8 wt% may include adding.

The surfactant may be at least one selected from the group consisting of cationic surfactants, anionic surfactants, phosphoric acid surfactants, fatty acid surfactants, acrylic surfactants, urethane surfactants, epoxy surfactants, and nonionic surfactants. and may be a polymer surfactant comprising at least one selected from the group consisting of carboxylic acids, amines, isocyanates, and derivatives thereof.

For example, the surfactant may be polyvinyl alcohol, sodium dodecylbenzene sulfonate, polyvinyl pyrrolidone, methyl polyethylene alkyl ether, alkylbenzene sulfonate, nonylphenol ether sulfate, sodium lauryl sulfate, lithium dodecyl sulfate, It may be at least one selected from the group consisting of alkyl phosphates, glyceryl esters, and polypropylene glycol esters. In the case of the particle dispersion method, the polyvinyl alcohol surfactant may be preferable in terms of high solubility, high reaction rate, low toxicity, and improved productivity and processability, but is not limited thereto.

In addition, the dispersing step may be performed by high-speed dispersion treatment for 1 minute to 90 minutes at a speed of 50% to 90% compared to the maximum rotation speed per minute (rpm) using a homogenizer. For example, the dispersing step may include 50% to 90%, 55% to 85%, 60% to 80%, 65% to 75% or 60% of the maximum rotational speed (rpm) using a homogenizer. High speed dispersion for 10 minutes to 90 minutes, 15 minutes to 80 minutes, 15 minutes to 70 minutes, 20 minutes to 60 minutes, 25 minutes to 55 minutes, 25 minutes to 45 minutes or 25 minutes to 40 minutes at a rate of to 70% It can be done by processing.

Alternatively, the dispersing step may be performed by ultrasonication with an energy amount of 20 Hz or more for 1 hour or less. For example, the dispersing step may be performed in an amount of energy of 20 Hz or more, 25 Hz or more, 30 Hz or more, 40 Hz or more, 50 Hz or more, or 60 Hz or less for 1 hour or less, 55 minutes or less, 50 minutes or less, 45 minutes or less, It may be performed by sonication for a time of 35 minutes or less or 30 minutes or less, or by sonication for a time of 1 minute or more, 2 minutes, 3 minutes or more, 5 minutes or more, 10 minutes or more, 15 minutes or more, or 20 minutes or more. can

By performing the dispersing step under the above conditions, dispersibility, dispersion stability, storage stability, coatability and processability may be further improved.

According to another embodiment of the present invention, the dispersing step is a first dispersing process; and secondary dispersion treatment.

Specifically, the dispersion step may be performed by filtering, washing, and secondary dispersion treatment of the first dispersion-treated first aqueous dispersion.

More specifically, in the dispersing step, the PHA obtained by cell disruption using a physical method in step (1), a mixture of the PHA and a surfactant, or a mixture of the PHA, a surfactant and a solvent is subjected to a primary dispersion treatment to prepare a first aqueous dispersion, and after filtering and washing the first aqueous dispersion, a solvent is additionally added, followed by secondary dispersion treatment to prepare a PHA dispersion.

The filtration step may be performed using a filter medium such as paper, woven fabric, nonwoven fabric, screen, polymer membrane or wedge wire, and may be a suction filter, a pressure filter, a membrane separator, a vacuum filter, a vacuum filter, an industrial filter press, a tube press. , a plate press, a gauge press, a belt press, a screw press, a disc press, a pressing function press or a centrifuge.

The washing step may be performed using a solvent. Specifically, the solvent used in the washing step may be water, distilled water, or a hydrophilic solvent, 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 alcohol It may be at least one selected from the group consisting of alcohol, 1-ethyl-1-propanol, 2-methyl-1-butanol, n-hexanol and cyclohexanol.

In addition, the solvent added to the filtered and washed primary aqueous dispersion may be water, distilled water, or a hydrophilic solvent. For example, the solvent added to the first aqueous dispersion may be the same as the solvent used in the washing step.

The first and second dispersing steps may be carried out by dispersing treatment for 20 to 60 minutes at a rate of 60% to 80% compared to the maximum rotation speed per minute (rpm) using a homogenizer. For example, the first and second dispersing steps may be performed at a rate of 60% to 80%, 65% to 75%, or 60% to 70% of the maximum rotational speed (rpm) using a homogenizer, respectively. It may be carried out by dispersing treatment for 20 to 60 minutes, 25 to 55 minutes, 25 to 45 minutes, or 25 to 40 minutes.

In addition, the dispersing step may be performed by dispersing the PHA obtained by cell disruption using a chemical method. Specifically, the dispersing step is performed by dispersing the PHA obtained by cell disruption using a chemical method in step (1), a mixture of the PHA and a surfactant, or a mixture of the PHA, a surfactant and a solvent to obtain a PHA dispersion solution. can be manufactured.

More specifically, the average particle diameter of PHA obtained by cell disruption using a mechanical or physical method in step (1) is higher than the average particle diameter of PHA obtained by cell disruption using a non-mechanical or chemical method. Because of the lower dispersibility of the cursor, it may be preferable that filtration, washing, and secondary dispersion treatment are additionally performed. However, since the average particle diameter of PHA obtained by cell disruption using a non-mechanical or chemical method in step (1) is relatively small and thus has higher dispersibility, filtration, washing and secondary dispersion steps are optionally additionally performed can do.

melt dispersion method

Another method for preparing a PHA dispersion according to an embodiment of the present invention comprises the steps of (1) preparing polyhydroxyalkanoate (PHA); and (2) dispersing the polyhydroxyalkanoate (PHA) in a solvent using a melt dispersion method.

First, polyhydroxyalkanoate (PHA) may be prepared (step (1)).

The description of the PHA is the same as described above.

In the melt dispersion method, unlike the particle dispersion method, the PHA prepared in step (1) may not be the PHA obtained by cell disruption using a non-mechanical or chemical method. Specifically, since the melt-dispersion method includes the step of melting PHA, the average particle diameter is relatively larger than that of PHA obtained by cell disruption using a non-mechanical or chemical method, and is suitable for cell disruption using a mechanical or physical method. Dispersibility can be further improved even by using the PHA obtained by

For example, even if the PHA obtained by cell disruption using a mechanical or physical method in step (1) is in a form with a large average particle size, such as granules or pellets, dispersibility can be further improved.

Thereafter, the polyhydroxyalkanoate (PHA) may be dispersed in a solvent using a melt dispersion method (step (2)).

Specifically, the dispersing step may include melting the polyhydroxyalkanoate (PHA); mixing the molten polyhydroxyalkanoate with a surfactant; and high-pressure dispersing in a solvent.

More specifically, after melting the PHA prepared in step (1), the melt or a mixture of the melt and the surfactant is subjected to a first dispersion treatment to prepare a first aqueous dispersion, and the first aqueous dispersion is dissolved in a solvent. A PHA dispersion can be prepared by secondary high-pressure dispersion treatment.

The melting step may be performed at 100 °C to 220 °C. For example, the melting step may be performed at 100 °C to 220 °C, 110 °C to 200 °C, 120 °C to 170 °C, or 130 °C to 160 °C.

In addition, the content of the surfactant mixed with the melt is 0.01 wt% to 30 wt%, 0.05 wt% to 25 wt%, 0.05 wt% to 20 wt%, 0.1 wt% to 15 wt% based on the total weight of the PHA dispersion based on the solid content wt%, 0.1 wt% to 10 wt%, 0.1 wt% to 5 wt%, 0.01 wt% to 5 wt%, 0.05 wt% to 4 wt%, 0.1 wt% to 5 wt%, 1 wt% to 5 wt% , 1.5 wt% to 5 wt%, 0.1 wt% to 3 wt%, or 0.1 wt% to 2.8 wt%.

Specifically, the surfactant is one selected from the group consisting of cationic surfactants, anionic surfactants, phosphoric acid-based surfactants, fatty acid-based surfactants, acrylic surfactants, urethane-based surfactants, epoxy-based surfactants, and nonionic surfactants It may be more than one species, and may be a polymer surfactant including one or more selected from the group consisting of carboxylic acids, amines, isocyanates, and derivatives thereof.

For example, the surfactant may be polyvinyl alcohol, sodium dodecylbenzene sulfonate, polyvinyl pyrrolidone, methyl polyethylene alkyl ether, alkylbenzene sulfonate, nonylphenol ether sulfate, sodium lauryl sulfate, lithium dodecyl sulfate, It may be at least one selected from the group consisting of alkyl phosphates, glyceryl esters, and polypropylene glycol esters. In the case of the melt dispersion method, sodium dodecylbenzene sulfonate surfactant may form an efficient core cell and may be preferable in that the zeta potential can be controlled in a desired range, but is not limited thereto.

The first dispersion treatment may be performed by dispersing treatment for 20 minutes to 60 minutes at a rate of 60% to 80% compared to the maximum rotation speed per minute (rpm) using a homogenizer. For example, the first or second dispersion step may be performed at a rate of 60% to 80%, 65% to 75%, or 60% to 70% of the maximum rotational speed per minute (rpm) using a homogenizer, respectively. It may be carried out by dispersing treatment for 20 to 60 minutes, 25 to 55 minutes, 25 to 45 minutes, or 25 to 40 minutes.

In addition, the second high-pressure dispersion treatment may be performed by high-pressure dispersion treatment for 20 minutes to 60 minutes at a rate of 60% to 80% compared to the maximum rotation speed per minute (rpm) using a homogenizer. For example, the second high-pressure dispersion step is performed at a rate of 60% to 80%, 65% to 75%, or 60% to 70% of the maximum rotational speed per minute (rpm) using a homogenizer for 20 minutes, respectively. It may be carried out by high-pressure dispersion dispersion treatment for 60 minutes, 25 minutes to 55 minutes, 25 minutes to 45 minutes, or 25 minutes to 40 minutes.

The solvent used in the secondary high-pressure dispersion treatment may be water, distilled water, or a hydrophilic solvent. Specifically, the solvent may be water, distilled water, or a hydrophilic solvent, 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 alcohol It may be at least one selected from the group consisting of alcohol, 1-ethyl-1-propanol, 2-methyl-1-butanol, n-hexanol and cyclohexanol.

solvent extraction

A method for preparing a PHA dispersion according to another embodiment of the present invention comprises the steps of (1) preparing polyhydroxyalkanoate (PHA); and (2) dispersing the polyhydroxyalkanoate (PHA) in a solvent using a solvent extraction method.

First, polyhydroxyalkanoate (PHA) may be prepared (step (1)).

The description of the PHA is the same as described above.

In the solvent extraction method, unlike the particle dispersion method, the PHA prepared in step (1) may not be the PHA obtained by cell disruption using a non-mechanical or chemical method. Specifically, since the solvent extraction method includes the step of preparing a first solution of PHA using a specific first solvent, the average particle diameter of PHA is relatively larger than that of PHA obtained by cell disruption using a non-mechanical or chemical method. Even if PHA obtained by cell disruption using a physical or physical method is used, dispersibility can be further improved.

For example, even if the PHA obtained by cell disruption using a mechanical or physical method in step (1) is in a form with a large average particle size, such as granules or pellets, dispersibility can be further improved.

Thereafter, the polyhydroxyalkanoate (PHA) may be dispersed in a solvent using a solvent extraction method (step (2)).

Specifically, the dispersing step may include preparing a first solution by mixing the polyhydroxyalkanoate (PHA) with a first solvent; preparing a second solution by mixing a surfactant with a second solvent; mixing the first solution and the second solution; and ultrasonically dispersing the mixture.

The first solvent is chloroform, ethyl acetate, butyl acetate, isobutyl acetate, amyl acetate, isoamyl acetate, propyl propionate, butyl propionate, isobutyl propionate, ethyl butyrate, isobutyl isobutyrate, dichloromethane , N,N-dimethylformamide, dimethylacetamide, dimethylsulfoxide, N-methylpyrrolidone, methylethylketone, methylene chloride, tetrahydrofuran, may be at least one selected from the group consisting of toluene and acetone.

By using a solvent having high solubility with PHA as the first solvent, dispersibility can be improved. Chloroform may be preferable in terms of high solubility with PHA, but is not limited thereto.

In the first solution preparation step, the weight ratio of the first solvent to the PHA may be 1: 9, 1.5: 8.5, 2: 8, or 3: 7.

The second solvent may be water, distilled water, or a hydrophilic solvent. Specifically, the solvent may be water, distilled water, or a hydrophilic solvent, 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 alcohol It may be at least one selected from the group consisting of alcohol, 1-ethyl-1-propanol, 2-methyl-1-butanol, n-hexanol and cyclohexanol.

The content of the surfactant mixed in the preparation step of the second solution is 0.01 wt% to 30 wt%, 0.05 wt% to 25 wt%, 0.05 wt% to 20 wt%, 0.1 wt% based on the total weight of the PHA dispersion based on the solid content % to 15 wt%, 0.1 wt% to 10 wt%, 0.1 wt% to 5 wt%, 0.01 wt% to 5 wt%, 0.05 wt% to 4 wt%, 0.1 wt% to 5 wt%, 1 wt% to 5 wt%, 1.5 wt% to 5 wt%, 0.1 wt% to 3 wt% or 0.1 wt% to 2.8 wt%.

Specifically, the surfactant is one selected from the group consisting of cationic surfactants, anionic surfactants, phosphoric acid-based surfactants, fatty acid-based surfactants, acrylic surfactants, urethane-based surfactants, epoxy-based surfactants, and nonionic surfactants It may be more than one species, and may be a polymer surfactant including one or more selected from the group consisting of carboxylic acids, amines, isocyanates, and derivatives thereof.

For example, the surfactant may be polyvinyl alcohol, sodium dodecylbenzene sulfonate, polyvinyl pyrrolidone, methyl polyethylene alkyl ether, alkylbenzene sulfonate, nonylphenol ether sulfate, sodium lauryl sulfate, lithium dodecyl sulfate, It may be at least one selected from the group consisting of alkyl phosphates, glyceryl esters, and polypropylene glycol esters. In the case of the solvent extraction method, the polyvinyl alcohol surfactant may be preferable in terms of improving miscibility due to fast and excellent solubility in the second solvent, particularly water or distilled water, but is not limited thereto.

In addition, the step of preparing the second solution may further include the step of dispersing treatment. For example, the dispersing step is performed using a homogenizer at a rate of 60% to 80%, 65% to 75%, or 60% to 70% of the maximum rotational speed per minute (rpm) for 20 minutes to 60 minutes, Dispersion treatment may be performed for 25 minutes to 55 minutes, 25 minutes to 45 minutes, or 25 minutes to 40 minutes.

Thereafter, the mixed solution of the first solution and the second solution may be subjected to ultrasonic dispersion treatment with an energy amount of 20 Hz or more for 1 hour or less. For example, the ultrasonic dispersion treatment is performed with an amount of energy of 20 Hz or more, 25 Hz or more, 30 Hz or more, 40 Hz or more, or 50 Hz or more for 1 hour or less, 55 minutes or less, 50 minutes or less, or 45 minutes or less. It may be carried out by treatment or by ultrasonication for a time of 5 minutes or more, 10 minutes or more, 15 minutes or more, or 20 minutes or more.

In addition, after the ultrasonic dispersion treatment step, the step of distilling the mixed solution of the first solution and the second solution under reduced pressure may be further performed. For example, the residual solvent may be removed from the mixed solution using a vacuum distiller at 60° C. or less, 50° C. or less, or 40° C. or less.

In addition, after the ultrasonic dispersion treatment step, after filtering and washing the mixed solution of the first solution and the second solution, the step of redispersing may be additionally performed. Specifically, after filtering and washing the mixture from which the residual solvent is removed through the reduced pressure distillation, the step of redispersing may be additionally performed.

The filtration step may be performed using a filter medium such as paper, woven fabric, nonwoven fabric, screen, polymer membrane or wedge wire, and may be a suction filter, a pressure filter, a membrane separator, a vacuum filter, a vacuum filter, an industrial filter press, a tube press. , a plate press, a gauge press, a belt press, a screw press, a disc press, a pressing function press or a centrifuge.

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

In addition, the redispersion is performed at a rate of 60% to 80%, 65% to 75%, or 60% to 70% of the maximum rotational speed per minute (rpm) using a homogenizer for 20 minutes to 60 minutes, 25 minutes Dispersion treatment may be performed for 55 minutes to 55 minutes, 25 minutes to 45 minutes, or 25 minutes to 40 minutes.

Method for manufacturing biodegradable article

A method for manufacturing a biodegradable article according to another embodiment of the present invention comprises the steps of preparing a polyhydroxyalkanoate (PHA) dispersion; and forming a biodegradable coating layer with the polyhydroxyalkanoate (PHA) dispersion.

The description of the preparation of the PHA dispersion is the same as described above.

Thereafter, a biodegradable coating layer is formed on one surface of the substrate using the PHA dispersion.

According to an embodiment of the present invention, the forming of the biodegradable coating layer may be performed by applying the PHA dispersion on the substrate and drying it.

The substrate is not limited as long as it is an article capable of forming a biodegradable coating layer on the surface of the substrate. For example, the substrate is paper, kraft paper, fabric, nonwoven fabric, polyethylene terephthalate (PET) film, polybutylene succinate (PBS), polybutylene adipate (PBA), polybutylene adipate terephthalate ( PBAT) and polybutylene succinate terephthalate (PBST) may be at least one selected from the group consisting of a polyester film and a polyimide (PI) film.

Specifically, the substrate may be preferably a single material substrate in terms of improving the coatability of the substrate, and the substrate may be paper, kraft paper, woven or non-woven fabric, but is not limited thereto. In addition, when the substrate includes paper or kraft paper, it may be more advantageous in providing an eco-friendly packaging material because it has superior biodegradability than other plastic materials.

The thickness of the substrate may be 20 μm or more. For example, the thickness of the substrate may be 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.

In addition, 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 fabric, knitted fabric or nonwoven 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 may be.

On the other hand, a barrier layer may be disposed on at least one surface of the substrate, and an eco-friendly blocking film is coated on the surface of the substrate to have barrier properties of moisture and/or oxygen, or a functional coating layer having antistatic performance or adhesive performance may include more. The functional coating layer may include a primer coating layer and an adhesive coating layer, which may have materials and properties commonly used as long as they do not impair the desired effect in the present invention.

In addition, the PHA dispersion applied on the substrate may be applied in an application amount ^{of 5 g/m 2} to 100 g/m ^{2 .} For example, the application amount is 5 g/m ² to 100 g/m ² , 5 g/m ² to 85 g/m ² , 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 or 10 g/m ² to 40 g/m ² . When the coating amount satisfies the above range, coatability, productivity, and workability can be further improved.

In addition, the application may be performed once to form a single coating layer, and may be performed two or more times to form a plurality of coating layers. The application amount may be adjusted within the above range according to the desired number of coating layers. Specifically, the application amount may be the total amount of the application amount applied to the plurality of coating layers.

After the PHA dispersion is applied on the substrate, it may be dried at 100° C. to 200° C. for 5 seconds to 30 minutes. For example, the drying may be performed at 100° C. to 200° C., 110° C. to 185° C., 120° C. to 180° C. or 130° C. to 175° C. for 5 seconds to 30 minutes, 10 seconds to 25 minutes, 20 seconds to 20 minutes, 30 seconds to 15 minutes or 40 seconds to 10 minutes.

The step of forming the biodegradable coating layer may be applied without being particularly limited as long as it is a coating process generally 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.

biodegradable products

A biodegradable article according to another embodiment of the present invention includes a substrate; and a biodegradable coating layer, wherein the biodegradable coating layer includes polyhydroxyalkanoate (PHA) particles.

Figure 3 shows a biodegradable article according to an embodiment of the present invention, Figure 4 shows a biodegradable article according to another embodiment of the present invention.

Specifically, FIG. 3 illustrates a biodegradable article 1 having a biodegradable coating layer 200 formed on one surface of the substrate 100 , and FIG. 4 is a biodegradable coating layer 200 formed on both sides of the substrate 100 . A biodegradable article (1) is illustrated.

The biodegradable article includes a biodegradable coating layer on one or both sides of the substrate, and the biodegradable coating layer contains polyhydroxyalkanoate (PHA) particles, so that it has excellent biodegradability and biocompatibility, so that it is environmentally friendly and has excellent dispersibility , coatability, productivity and processability.

The description of the description is the same as described above.

In addition, the thickness of the biodegradable coating layer may be 5 μm to 50 μm, 5 μm to 40 μm, or 6 μm to 30 μm, but is not limited thereto.

The biodegradable article including the biodegradable coating layer may be a packaging material, a corrugated cardboard box, a shopping bag, disposable tableware, a packaging container, or a paper straw, but is not limited thereto.

The above will be described in more detail with reference to the following examples. However, the following examples are only for illustrating the present invention, and the scope of the examples is not limited thereto.

[Example]

Preparation of PHA Dispersion

<Particle dispersion method>

Example 1

(1) PHA preparation step

Content of polyhydroxyalkanoate (PHA) (4-hydroxybutyrate (4-HB): 10% by weight, weight average molecular weight (Mw): 800,000 g/mol, polydispersity index (PDI): 2.0, manufacturer: CJ) powder was prepared. The PHA powder was obtained by physical crushing using a homogenizer (product name: homomixer mark2, manufacturer: primix).

(2) Preparation of PHA dispersion

30 parts by weight of the PHA powder, 20 parts by weight of polyvinyl alcohol (PVA, manufacturer: kuraray, hydration rate: 80%) of 10% concentration as a surfactant, and 50 parts by weight of distilled water (DI water) in 1L of glass Put it in a beaker, and use a homogenizer (homogenizer, linear speed: 1,250 cm/sec, product name: Homomixer mark2, manufacturer: primix, maximum revolutions per minute: 12,000 rpm) for 30 minutes at 70% of the maximum revolutions per minute. The first dispersion treatment was performed to prepare a first aqueous dispersion.

Thereafter, the first aqueous dispersion is filtered using a pressure filter, washed with water, distilled water is further added, and a second dispersion treatment is performed in an aqueous system using a homogenizer (product name: homomixer mark2, manufacturer: primix). Thus, a PHA dispersion having a solid content of 40% by weight was prepared.

<Method for dispersing melt>

Example 2

(1) PHA preparation step

Content of polyhydroxyalkanoate (PHA) (4-hydroxybutyrate (4-HB): 10% by weight, weight average molecular weight (Mw): 800,000 g/mol, polydispersity index (PDI): 1.9, manufacturer: CJ) granules were prepared. The PHA granules are obtained by physical crushing using a homogenizer (product name: homomixer mark2, manufacturer: primix).

(2) Preparation of PHA dispersion

After melting 30 parts by weight of the PHA granules at 170° C., it was mixed with 2 parts by weight of sodium dodecylbenzene sulfonate (SDS), and a homogenizer (linear speed: 1,250 cm/sec), product name: Homomixer mark2 , manufacturer: primix, maximum rotational speed: 12,000 rpm) was used to prepare a primary aqueous dispersion by primary dispersion treatment at a speed of 70% compared to the maximum rotational speed for 30 minutes.

Thereafter, the first aqueous dispersion was subjected to a second high-pressure dispersion treatment for 30 minutes using a high-pressure homogenizer (product name: homomixer mark2, manufacturer: premix, maximum rotational speed: 8,000 rpm) in a solvent to have a solid content of 40 wt% A PHA dispersion with

<Solvent extraction method>

Example 9

(1) PHA preparation and first solution preparation

Content of polyhydroxyalkanoate (PHA) (4-hydroxybutyrate (4-HB): 10% by weight, weight average molecular weight (Mw): 800,000 g/mol, polydispersity index (PDI): 2.0, manufacturer: CJ) pellets were prepared. The PHA pellets were obtained by physical crushing using a homogenizer (product name: homomixer mark2, manufacturer: primix).

A first solution was prepared by mixing 10 parts by weight of the PHA pellets with 90 parts by weight of chloroform.

(2) Preparation of the second solution

20 parts by weight of polyvinyl alcohol (PVA, manufacturer: kuraray, hydration rate: 80%) with a concentration of 2% as a surfactant (PVA) is placed in a 1L glass beaker, distilled water as a second solvent is added, and a homogenizer ( Using a homogenizer, linear speed: 1,250 cm/sec, product name: Homomixer mark2, manufacturer: primix, maximum revolutions per minute: 12,000 rpm), the second solution was dispersed for 5 minutes at 10% of the maximum revolutions per minute. prepared.

(3) Preparation of PHA dispersion

The mixed solution obtained by mixing the first solution and the second solution was subjected to ultrasonic dispersion treatment with an energy of 35 Hz for 30 minutes.

After removing the residual solvent at 40°C using a vacuum distiller (product name: N-21000, manufacturer: eyela), the ultrasonic dispersion-treated mixed solution is filtered using a pressure filter, washed with water, and then redispersed in water. to prepare a PHA dispersion having a solid content of 40% by weight.

[Experimental example]

Experimental Example 1: Haze

For the PHA dispersions of Examples 1 to 3, haze was measured using a haze meter (CM-5 manufactured by Konica Minolta).

Experimental Example 2: Color

For the PHA dispersions of Examples 1 to 3, L*, a*, and b*, which are color characteristics, were measured using a spectrocolorimeter CM-5 (manufacturer: Konica Minolta).

Experimental Example 3: Yellowness (Y.I.)

With respect to the PHA dispersions of Examples 1 to 3, yellowness was measured according to ASTM E313 using an optical measuring device, a spectrocolorimeter CM-5 (manufactured by Konica Minolta).

Experimental Example 4: Zeta potential

For the PHA dispersions of Examples 1 to 3, the zeta potential was measured using a ZetaPlus Zeta Potential Analyzer (manufactured by: Brookhaven Instruments).

Experimental Example 5: Average particle diameter and particle size deviation

Dynamic light scattering (DLS) at a temperature of 25 ° C and a measurement angle of 175 ° using a nano particle size analyzer (product name: Zetasizer Nano ZS, manufacturer: Marven) for the PHA particles included in the PHA dispersions of Examples 1 to 3 ), the average particle diameter and particle size deviation were measured. At this time, the value of the peak derived through the polydispersity index (PDI) in the confidence interval of 0.5 was measured as the particle size.

Experimental Example 6: Dispersion Stability

After putting the PHA dispersions of Examples 1 to 3 into test tubes and leaving them at 50°C for 2 weeks, dispersion stability was visually evaluated according to the following evaluation criteria.

◎: Phase separation and precipitation do not occur.

○: A slight phase separation occurred, but no precipitation occurred.

△: Partial phase separation and precipitation occurred.

x: Phase separation and precipitation occurred clearly.

Experimental Example 7: Viscosity

For the PHA dispersions of Examples 1 to 3, the viscosity was measured at 23° C. at a shear rate of 12 rpm using a viscometer (manufacturer: Brookfiled) that measures shear stress according to shear rate.

division haze (%) L* a* b* Y.I. Zeta avant-garde
(mV) average particle diameter
(μm) particle size deviation
(μm) Example 1 305 48.86 0.34 4.53 11.57 -56.1 2.75 ±0.3 Example 2 325 54.69 0.11 5.46 12.72 -63.5 2.13 ±0.3 Example 3 305 48.13 0.38 4.44 11.45 -58.5 3.17 ±0.3

division dispersion stability Viscosity (mPa s) Example 1 ◎ 260 Example 2 ○ 120 Example 3 ○ 180

As shown in Tables 1 and 2, the PHA dispersions of Examples 1 to 3 were excellent in dispersibility and processability.

Specifically, the PHA dispersions of Examples 1 to 3 were prepared by the particle dispersion method, melt dispersion method, or solvent extraction method according to an embodiment of the present invention, so that the average particle diameter and particle size deviation of the PHA particles included in the PHA dispersion were specific. The range was satisfied, and the zeta potential, dispersion stability, and viscosity properties all satisfied the preferable ranges, thereby exhibiting excellent dispersibility and processability.

1: Biodegradable article
100: description
200: biodegradable coating layer

Claims (15)

A method for preparing a polyhydroxyalkanoate (PHA) dispersion comprising the step of dispersing polyhydroxyalkanoate (PHA) in a solvent using a particle dispersing method, a melt dispersing method or a solvent extraction method. The method of claim 1,
The method for preparing the polyhydroxyalkanoate (PHA) dispersion is at least one selected from the group consisting of an agitator, a homogenizer, a high-pressure homogenizer, a high-pressure disperser (microfluidizer) and a colloid mill. performed by the device, or
A method for preparing a polyhydroxyalkanoate (PHA) dispersion, which is performed by at least one method selected from the group consisting of high shear force, ultrasonic emulsification (ultra sonicator), and membrane emulsification. The method of claim 1,
A method for preparing a polyhydroxyalkanoate (PHA) dispersion, wherein the molecular weight of the polyhydroxyalkanoate (PHA) is 10,000 g/mol to 1,200,000 g/mol. The method of claim 1,
A method for producing a polyhydroxyalkanoate (PHA) dispersion, wherein the polyhydroxyalkanoate dispersion has a solid content of 10% to 60% by weight. The method of claim 1,
The polyhydroxyalkanoate (PHA) is 3-hydroxybutyrate (3-HB), 4-hydroxybutyrate (4-HB), 3-hydroxypropionate (3-HP), 3-hydroxy Hexanoate (3-HH), 3-hydroxyvalerate (3-HV), 4-hydroxyvalerate (4-HV), 5-hydroxyvalerate (5-HV) and 6-hydroxyhexa A method for producing a polyhydroxyalkanoate (PHA) dispersion, which is a polyhydroxyalkanoate (PHA) copolymer comprising at least one repeating unit selected from the group consisting of noate (6-HH). 6. The method of claim 5,
The polyhydroxyalkanoate (PHA) copolymer contains 0.1 wt% to 60 wt% of a 4-hydroxybutyrate (4-HB) repeating unit based on the total weight of the polyhydroxyalkanoate (PHA) copolymer A method for preparing a polyhydroxyalkanoate (PHA) dispersion comprising a. The method of claim 1,
(1) preparing the polyhydroxyalkanoate (PHA) obtained by cell disruption using a physical or chemical method; and
(2) A method for preparing a polyhydroxyalkanoate (PHA) dispersion comprising the step of dispersing the polyhydroxyalkanoate (PHA) in a solvent using a particle dispersing method. 8. The method of claim 7,
The step (2) comprises adding a surfactant in an amount of 0.01 wt% to 30 wt% based on the total weight of the dispersion,
The surfactant is at least one selected from the group consisting of cationic surfactants, anionic surfactants, phosphoric acid surfactants, fatty acid surfactants, acrylic surfactants, urethane surfactants, epoxy surfactants and nonionic surfactants, or A method for preparing a polyhydroxyalkanoate (PHA) dispersion, which is a polymer surfactant comprising at least one selected from the group consisting of , carboxylic acids, amines, isocyanates and derivatives thereof. 8. The method of claim 7,
Polyhydroxyalkanoate (PHA) dispersion, wherein the dispersion step is high-speed dispersion treatment for 1 minute to 90 minutes at a rate of 50% to 90% compared to the maximum rotation speed (rpm) per minute using a homogenizer manufacturing method. 8. The method of claim 7,
The dispersing step is
Including the step of primary dispersion processing and secondary dispersion processing,
A method for producing a polyhydroxyalkanoate (PHA) dispersion, wherein the primary dispersion-treated primary aqueous dispersion is filtered, washed, and secondary dispersion-treated. The method of claim 1,
(1) preparing polyhydroxyalkanoate (PHA); and
(2) dispersing the polyhydroxyalkanoate (PHA) in a solvent using a melt dispersion method;
The dispersing step is
melting the polyhydroxyalkanoate (PHA);
mixing the molten polyhydroxyalkanoate with a surfactant; and
A method for preparing a polyhydroxyalkanoate (PHA) dispersion comprising the step of high-pressure dispersion in a solvent. 12. The method of claim 11,
A method for preparing a polyhydroxyalkanoate (PHA) dispersion, wherein the melting step is performed at 100° C. to 200° C. The method of claim 1,
(1) preparing polyhydroxyalkanoate (PHA); and
(2) dispersing the polyhydroxyalkanoate (PHA) in a solvent using a solvent extraction method;
The dispersing step is
preparing a first solution by mixing the polyhydroxyalkanoate (PHA) with a first solvent;
preparing a second solution by mixing a surfactant with a second solvent;
mixing the first solution and the second solution; and
A method for preparing a polyhydroxyalkanoate (PHA) dispersion, comprising the step of ultrasonic dispersion treatment. 14. The method of claim 13,
The first solvent is chloroform, ethyl acetate, butyl acetate, isobutyl acetate, amyl acetate, isoamyl acetate, propyl propionate, butyl propionate, isobutyl propionate, ethyl butyrate, isobutyl isobutyrate, dichloromethane , N,N-dimethylformamide, dimethylacetamide, dimethylsulfoxide, N-methylpyrrolidone, methylethylketone, methylene chloride, tetrahydrofuran, at least one selected from the group consisting of toluene and acetone,
The method for preparing a polyhydroxyalkanoate (PHA) dispersion, wherein the second solvent is water or a hydrophilic solvent. 14. The method of claim 13,
The method for producing a polyhydroxyalkanoate (PHA) dispersion, wherein the ultrasonic dispersion treatment is performed for 1 hour or less with an energy amount of 20 Hz or more.

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