PHA composition and method for producing same

Abstract

The present invention relates to a polyhydroxyalkanoic acid (PHA) composition with improved stability and water resistance, and a method for preparing the same. According to the present invention, it is possible to prevent aggregation between particles of polyhydroxyalkanoic acid (PHA) dispersed in an aqueous system, induce redispersion, and prevent precipitation, thereby improving the dispersion stability and water resistance of PHA. Furthermore, the composition of the present invention minimizes additives, allowing the recycling of biodegradable PHA, and has excellent compatibility with existing commonly used products and room temperature stability. Furthermore, the PHA manufacturing process does not require excessive use of surfactants or additional process steps for emulsion formation, thereby improving economic efficiency.

Description

[Technical field]

[0001] The present invention relates to a polyhydroxyalkanoic acid (PHA) composition having improved stability and water resistance, and a method for producing the same.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2020-0143256, filed on October 30, 2020, and all contents disclosed in the documents of the Korean Patent Application are incorporated herein by reference. [Background technology]

[0003] Polyhydroxyalkanoates (PHAs) are biodegradable plastics that are used, without limitation, in the manufacture of films (e.g., packaging films, agricultural films, mulch films), golf tees, caps and closures, agricultural supports and stakes, paper and board coatings (e.g., cups, plates, boxes, etc.), thermoformed products (e.g., trays, containers, yogurt pots, flower pots, noodle bowls, molded products, etc.), housings (e.g., for electronic products), bags (e.g., garbage bags, sundries bags, food bags, fertilizer bags, etc.), hygiene products (e.g., diapers, feminine hygiene products, urinary incontinence products, disposable wipes, etc.), and coatings for granular products (e.g., granular fertilizer, herbicides, insecticides, seeds, etc.).

[0004] PHAs are also used in the development of biomedical devices including sutures, repair devices, repair patches, slings, cardiovascular patches, orthopedic pins, attachment barriers, stents, guided tissue repair / regeneration devices, artificial cartilage repair devices, nerve guidance devices, tendon repair devices, bone marrow scaffolds, and wound dressings.

[0005] Polyhydroxyalkanoic acid (PHA) is produced by a fermentation process. When PHA is physically dispersed in an aqueous system, the particles aggregate and precipitate due to their self-aggregation forces, and the precipitated particles form a single mass due to strong attractive forces.

[0006] Korean Patent Publication No. 10-0602193 discloses an emulsion polymerization method in which a polyester (including PHA) resin is dispersed by reacting at a temperature of 230° C. or higher for a total of 10 hours or more, and then a surfactant is added.

[0007] In the past, to maintain dispersion stability in an aqueous system, a surfactant was generally used to carry out the polymerization process in the form of an emulsion. In this case, a process involving coating each particle one by one on the monomer or forming a micelles is carried out. In this case, a large amount of additives and a polymerization process of 10 hours or more under nitrogen purging are required. The surfactant used in the micellization process requires a high temperature reaction of 80°C or more, which is a disadvantage in that the manufacturing process is complicated.

[0008] Therefore, research is needed to simplify the process while improving the physical properties of PHA so that it is suitable for the intended use, thereby enabling efficient and economical use of PHA. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Korean Patent No. 10-0602193 Summary of the Invention [Problem to be solved by the invention]

[0010] An object of the present invention is to provide a polyhydroxyalkanoic acid (PHA) composition having improved dispersion stability and water resistance.

[0011] It is also an object of the present invention to provide a method for producing the PHA composition. [Means for solving the problem]

[0012] In order to solve the above problems, the present invention provides a PHA composition comprising, based on the total weight of the composition, 10-70 wt % of a polyhydroxyalkanoic acid (PHA); and 1-10 wt % of an additive; the PHA comprises poly-3-hydroxybutyrate-co-4-hydroxybutyrate (P3HB-4HB), the content of 4HB in the PHA copolymer is 0.1-20%, the additive comprises a rheology modifier together with a surfactant or dispersant, and the surfactant or dispersant is contained in an amount of less than 0.3 wt % based on the total weight of the composition.

[0013] According to an embodiment, the molecular weight of the PHA is Mw 10,000 to 1,000,000, and the particle size of the PHA is 10 μm or less.

[0014] According to an embodiment, the surfactant may include one or more selected from the group consisting of cationic, anionic, nonionic, and amphoteric surfactants.

[0015] According to an embodiment, the additive may further include one or more selected from the group consisting of a thickener and an antifoaming agent.

[0016] According to an embodiment, the rheology control agent may include one or more selected from the group consisting of gums, acrylics, urethanes, and epoxies.

[0017] The gums are not spherical and are acidic polysaccharides, and may include, for example, gellan gum, xanthan gum, carrageenan, curdlan gum, karaya gum, tragacanth gum, ghatti gum, algin, agar gum, and furcellaran.

[0018] According to an embodiment, the dispersant may include at least one selected from the group consisting of an acrylic dispersant, a urethane dispersant, an epoxy dispersant, polyvinyl alcohol, and cellulose.

[0019] According to one embodiment, the rheology control agent is present in an amount of 0.5% by weight or less based on the total weight of the composition.

[0020] The molecular weight of the polyvinyl alcohol is Mw 10,000 to 200,000, and the degree of saponification is 80 to 99 mol %.

[0021] According to one embodiment, the coating amount of the composition is 10 g / m 2 More than 30g / m 2 It is.

[0022] The Cobb value of the composition is 3 g / m 2 More than 20g / m 2 It is.

[0023] According to another embodiment of the present invention, there is provided a method for producing a PHA composition, the method including the steps of: preparing an aqueous PHA dispersion; and adding an additive while stirring the dispersion.

[0024] Further details of the embodiment of the present invention are included in the following detailed description. Effect of the Invention

[0025] According to the present invention, it is possible to prevent aggregation between particles of polyhydroxyalkanoic acid (PHA) dispersed in water and to induce redispersion to prevent precipitation, thereby improving the dispersion stability and water resistance of PHA.

[0026] In addition, the composition of the present invention can recycle biodegradable PHA by minimizing additives, has excellent compatibility with existing commonly used products, and has excellent room temperature stability.

[0027] In addition, the production process of PHA does not require excessive use of surfactants or an additional process step for emulsion formation, which can improve economic efficiency. [Brief description of the drawings]

[0028] [Figure 1] 1 is a photograph confirming the dispersion stability of an example. [Diagram 2]13 is a photograph confirming the dispersion stability of the comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] Since the present invention can be modified in various ways and has various embodiments, specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to a specific embodiment, and it should be understood that the present invention includes all modifications, equivalents, or alternatives within the spirit and technical scope of the present invention. In describing the present invention, if it is determined that a detailed description of related publicly known technology may obscure the gist of the present invention, the detailed description will be omitted.

[0030] Unless otherwise specified in the specification, the term "to" is used as an inclusive expression. For example, the term "1 to 2" does not only include 1 and 2, but also includes all numbers between 1 and 2.

[0031] In this specification, the singular expression includes the plural expression unless otherwise specified.

[0032] As used herein, the term "PHA copolymer" refers to a polymer comprised of at least two different hydroxyalkanoic acid monomers.

[0033] Hereinafter, polyhydroxyalkanoic acid (PHA) compositions and methods for preparing the same according to embodiments of the present invention will be described in more detail.

[0034] Specifically, the present invention provides a PHA composition comprising, based on the total weight of the composition, 10-70 wt % of a polyhydroxyalkanoic acid (PHA); and 1-10 wt % of an additive; the PHA comprises poly-3-hydroxybutyrate-co-4-hydroxybutyrate (P3HB-4HB), the content of 4HB in the PHA copolymer is 0.1-20%, the additive comprises a rheology modifier together with a surfactant or dispersant, and the surfactant or dispersant is contained in an amount of less than 0.3 wt % based on the total weight of the composition.

[0035] According to an embodiment, the composition of the present invention may contain 10 to 70 wt %, for example, 20 wt % or more, or 30 wt % or more, for example, 60 wt % or less, or 50 wt % or less of PHA polymer. The content of PHA polymer in the composition affects the physical properties of the composition. If the PHA content is too low, the coating film formed is not uniform and physical properties such as water resistance are reduced, and if the PHA content is too high, the surface coating properties may be hindered when coating a thin film with a low thickness.

[0036] In addition, the molecular weight of the PHA polymer in the composition depends on factors that affect the physical properties of the composition, and the weight average molecular weight of the PHA is Mw 10,000 to 1,000,000, for example, Mw 100,000 or more, Mw 200,000 or more, Mw 300,000 or more, for example, Mw 700,000 or less, or Mw 600,000 or less. If the molecular weight of the PHA is too low, the flexibility decreases during film formation, and if it is too high, the high-temperature drying and film formation speed decreases, resulting in poor processability.

[0037] According to one embodiment, the content of 4HB (4-hydroxybutyrate) in the PHA copolymer is a factor that affects the physical properties of PHA. The content of 4HB in the PHA copolymer of the present invention is 0.1 to 20%, for example, 0.1% or more, 1% or more, 2% or more, 3% or more, for example, 20% or less, 15% or less, or 10% or less. If the content of 4HB in the PHA is too low, the crystallinity increases, resulting in increased hardness, which may cause cracks after film formation or difficulty in adhesion to the substrate due to shrinkage after coating. If the content of 4HB is too high, the physical properties may change to an amorphous polymer, resulting in loss of water resistance.

[0038] According to one embodiment, the particle size of the PHA is 10 μm or less, for example, 5 μm or less, for example, 2 μm or less. The PHA of the present invention is suitable for use in coating agents because it has a small particle size and can be uniformly applied.

[0039] According to one embodiment, the composition of the present invention may include 1 to 10 wt % of the additive, for example, 1 wt % or more, or 2 wt % or more, or 3 wt % or more, for example, 10 wt % or less, or 8 wt % or less, or 7 wt % or less.

[0040] The additive may include, for example, one or more selected from the group consisting of a rheology modifier, a dispersant, a thickener, an antifoaming agent, and a surfactant, and may include, for example, a rheology modifier, a dispersant, and a thickener. In addition, as a specific example, the additive may include a surfactant or a dispersant, and may include a rheology modifier together with the surfactant or dispersant.

[0041] The rheology modifier may include one or more selected from the group consisting of gums, acrylics, urethanes, and epoxies. According to an embodiment, the gum rheology modifier used in the present invention is a non-spherical particle. The non-spherical gum rheology modifier may include acidic polysaccharides, and specific examples thereof include gellan gum, xanthan gum, carrageenan, curdlan gum, karaya gum, tragacanth gum, ghatti gum, algin, agar gum, and furcellaran. The content of the rheology modifier is 0.5% by weight or less, for example, 0.3% by weight or less, 0.1% by weight or less, 0.05% by weight or less, or 0.001% by weight or more, 0.01% by weight or more, based on the total composition.

[0042] The dispersant may be an aqueous dispersant, and may include, for example, one or more selected from the group consisting of acrylic dispersants, urethane dispersants, epoxy dispersants, pigment dispersants, polyvinyl alcohol, and cellulose. Specific examples include polyvinyl alcohol (PVA). When the composition of the present invention includes PVA, the weight average molecular weight is Mw 10,000 to 200,000, for example, Mw 10,000 to 100,000, for example, Mw 10,000 to 50,000, and any grade may be used.

[0043] The degree of hydrolysis (DH) of the PVA is 80 to 99 mol%, for example, 80 mol% or more, or 85 mol% or more, for example, 99 mol% or less, or 98 mol% or less, or 94 mol% or less, or 90 mol% or less.

[0044] Antifoaming agents include alcohol, silicone oil, and water-soluble surfactants, and may include octanol, cyclohexanol, ethylene glycol, sorbitan fatty acid esters, and the like.

[0045] The surfactant may include one or more of cationic, anionic, nonionic and amphoteric surfactants.

[0046] The cationic surfactant may include, for example, a quaternary ammonium salt, an alkylpyridinium salt, an alkylimidazolinium salt, an aliphatic amine salt, etc. Specifically, for example, the cationic surfactant may include a dialkyldimethylammonium salt, an alkylbenzylmethylammonium salt, a benzalkonium chloride, etc.

[0047] Anionic surfactants may include, for example, sodium fatty acid salts, monoalkyl sulfates, alkylbenzene sulfonates, monoalkyl phosphates, sodium lauryl sulfate (SDS), and the like.

[0048] Nonionic surfactants include polyoxyethylene alkyl ethers, fatty acid sorbitan esters, fatty acid diethanolamines, alkyl mono glyceryl ethers, and the like, and specific examples thereof include Tween 20, Triton X, Pluronic, and the like.

[0049] The amphoteric surfactant may include imidazoline-based and betaine-based surfactants, and specific examples thereof include cocamidopropyl betaine, lauryl hydroxy sulfobetaine, alkyl sulfobetaine, and alkyl carboxybetaine.

[0050] In the present invention, an emulsion forming process is not required as an essential component, and a surfactant is not required as an essential component. Therefore, when a surfactant is included in the composition of the present invention, it is used in an amount of less than 0.3 wt %, for example, 0.25 wt % or less, or 0.2 wt % or less, or for example, 0.0001 wt % or more, 0.001 wt % or more, or 0.01 wt % or more, based on the total weight of the composition, specifically, the solid content weight of the entire composition. Also, the surfactant is used as a dispersant instead of the surfactant.

[0051] If the surfactant is used at 0.3% by weight or more, the hydrophobic region of the surfactant increases, making it difficult to disperse uniformly in the water dispersion, and there are problems with the formation of an interface during coating.In addition, after dispersion, redispersion is difficult when the particles settle, and the PHA particles may aggregate together and form lumps.

[0052] According to the present invention, the use of additives such as surfactants can be significantly reduced, thereby making it possible to carry out the PHA production process economically and efficiently.

[0053] The additives of the present invention are not limited to the above types, and are not particularly limited as long as they are commonly used by those skilled in the art.

[0054] According to another embodiment of the present invention, there is provided a method for producing a PHA composition, comprising the steps of: preparing an aqueous PHA dispersion; and adding an additive while stirring the dispersion; wherein 4HB in the PHA copolymer is 0.1-20 wt %, the additive includes a rheology modifier together with a surfactant or dispersant, the surfactant or dispersant is less than 0.3 wt % based on the total weight of the composition, and the PHA in the final composition is 10-70 wt %.

[0055] According to an embodiment, the step of preparing the PHA aqueous dispersion may include a step of distilling a PHA aqueous dispersion having a solid content of, for example, 1 to 10%, e.g., 3 to 8%, or a step of dispersing the solid PHA powder dispersion through a disperser.

[0056] According to one embodiment, the step of adding the additive while stirring the dispersion is carried out at room temperature. The present invention is economical because a separate low-temperature or high-temperature operation is not necessarily required to improve the dispersibility. When stirring is carried out at room temperature, it is carried out at a temperature of 20 to 30°C, for example, 23 to 26°C.

[0057] The step of adding the additive may include adding a surfactant or dispersant in an amount of 0.1 to 5 wt %, for example, 0.1 wt % or more, or 0.5 wt % or more, or 1 wt % or more, or 2 wt % or more, for example, 5 wt % or less, or 4 wt % or less, or 3 wt % or less.

[0058] Also, the method may include adding a surfactant or dispersant so that the surfactant or dispersant is contained in the composition according to the present invention at 0.3 wt % or less, for example, 0.25 wt % or less, for example, 0.2 wt % or less.

[0059] The method may also include a step of adding a rheology modifier such that the rheology modifier is contained in the composition according to the present invention at 0.1 to 5 wt%, for example, 0.1 wt% or more, or 0.5 wt% or more, or 1 wt% or more, or 2 wt% or more, for example, 5 wt% or less, or 4 wt% or less, or 3 wt% or less.

[0060] According to one embodiment, the coating amount of the composition according to the present invention is 10 g / m 2 More than 30g / m 2 , e.g., 11 g / m 2 More than 12g / m 2 More than 13g / m 2 Above 25g / m 2 Below 20g / m 2 The following is the result.

[0061] The Cobb value of the composition according to the present invention is 3 to 20 g / m 2 , e.g., 4g / m 2 More than 5g / m 2 Above 15g / m 2 Below 10g / m 2Within the above range, the coating may have suitable water resistance.

[0062] According to an embodiment, the composition according to the present invention can be prepared as a coating agent, specifically, a latex composition that can be used as a coating agent for paper materials such as paper cups, books, printed matter, shopping bags, etc., or a coating agent for polymer film materials such as esters such as PET, EVOH, etc. Also, it can be prepared as a food packaging material such as oil paper, pizza boxes, bread bags, etc.

[0063] In addition, the physical properties of the PHA can be optimized to improve dispersibility and water resistance for coating applications.

[0064] According to the present invention, the use of additives is minimized, an additional process for emulsion formation is not required, and the content of surfactants is minimized, so that the PHA composition can be produced economically and efficiently.

[0065] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention may be embodied in various different forms and should not be construed as limited to the embodiments set forth herein.

[0066] Example 1 An aqueous dispersion of PHA (CJ CheilJedang, Mw 600,000, PDI 1.9, <2μm particle size, 4HB 10%) having a solid content of 5% was distilled under reduced pressure to produce an aqueous dispersion having a solid content of 41%.

[0067] 98 parts of the prepared 41% PHA aqueous dispersion was stirred at room temperature at 1500 rpm in a stirrer equipped with a paddle or turbine type impeller, while 1 part of 10% dissolved polyvinyl alcohol (PVA, Kuraray, Mw 14,200, degree of hydrolysis (DH) 88 mol%) was added and stirred for 1 hour.

[0068] Then, 1 part of 5% xanthan gum (Dyne Materials) dispersion was added and stirred for an additional 10 minutes to prepare a 40% PHA aqueous coating solution.

[0069] Thus, a composition was prepared containing 10% PVA, 0.24% by weight and 5% xanthan gum, 0.12% by weight on PHA solids.

[0070] Example 2 39 parts of completely dried PHA powder (CJ CheilJedang, Mw 600,000, PDI 1.9, 4HB 10% by weight) with a particle size of 2μm or less was mixed with 56 parts of deionized water and dispersed in a high-pressure disperser at room temperature for 2 hours to produce a PHA aqueous dispersion with a solid content of 41%.

[0071] 98 parts of the 41% PHA aqueous dispersion prepared above was stirred at room temperature at 1500 rpm in a stirrer having a paddle or turbine type impeller, while 1 part of 10% dissolved polyvinyl alcohol (PVA, Kuraray, Mw 14,200, DH 88%) was added and stirred for 1 hour.

[0072] Then, 1 part of 5% xanthan gum (Dyne Materials) dispersion was added and stirred for an additional 10 minutes to prepare a 40% PHA aqueous coating solution.

[0073] Thus, a composition was prepared containing 10% PVA, 0.24% by weight and 5% xanthan gum, 0.12% by weight on PHA solids.

[0074] Example 3 An aqueous dispersion of PHA (CJ CheilJedang, Mw 600,000, PDI 1.9, <2 μm particle size, 4HB 10 wt%) having a solid content of 5% was distilled under reduced pressure to produce an aqueous dispersion having a solid content of 41%.

[0075] The 41% PHA aqueous dispersion (99 parts) was stirred at room temperature at 1500 rpm in a stirrer having a paddle or turbine type impeller, and 0.1 parts of SDS (Sodium Lauryl Sulfate, Sigma Aldrich) was added and stirred for 1 hour.

[0076] Then, 1 part of 5% xanthan gum (Dyne Materials) dispersion was added and stirred for an additional 10 minutes to prepare a 40% PHA aqueous coating solution.

[0077] That is, a composition was prepared containing 0.24% SDS and 0.12% xanthan gum by weight relative to the PHA solids content.

[0078] Example 4 An aqueous dispersion of PHA (CJ CheilJedang, Mw 600,000, PDI 1.9, <2 μm particle size, 4HB 10 wt%) having a solid content of 5% was distilled under reduced pressure to produce an aqueous dispersion having a solid content of 41%.

[0079] 98 parts of the 41% PHA aqueous dispersion prepared above was stirred at room temperature at 1500 rpm in a stirrer having a paddle or turbine type impeller, while 1 part of 10% dissolved polyvinyl alcohol (PVA, Kuraray, Mw 14,200, DH 88%) was added and stirred for 1 hour.

[0080] Then, 1 part of 5% gellan gum (Dyne Materials) dispersion was added and stirred for an additional 10 minutes to prepare a 40% PHA aqueous coating solution.

[0081] Thus, a composition was prepared containing 10% PVA, 0.24% by weight and 5% gellan gum, 0.12% by weight on PHA solids.

[0082] Example 5 An aqueous dispersion of PHA (CJ CheilJedang, Mw 600,000, PDI 1.9, <2 μm particle size, 4HB 10 wt%) having a solid content of 5% was distilled under reduced pressure to produce an aqueous dispersion having a solid content of 41%.

[0083] 98 parts of the 41% PHA aqueous dispersion prepared above was stirred at room temperature at 1500 rpm in a stirrer having a paddle or turbine type impeller, while 1 part of 10% dissolved polyvinyl alcohol (PVA, Kuraray, Mw 14,200, DH 88%) was added and stirred for 1 hour.

[0084] Then, 1 part of 5% carrageenan (ES Food Ingredients) dispersion was added and stirred for an additional 10 minutes to prepare a 40% PHA aqueous coating solution.

[0085] That is, a composition was prepared containing 10% PVA, 0.24% by weight and 5% carrageenan, 0.12% by weight on PHA solids.

[0086] Comparative Example 1 An aqueous dispersion of PHA (CJ CheilJedang, Mw 600,000, PDI 1.9, <2 μm particle size, 4HB 10 wt%) having a solid content of 5% was distilled under reduced pressure to produce an aqueous dispersion having a solid content of 40%.

[0087] Comparative Example 2 An aqueous dispersion of PHA (CJ CheilJedang, Mw 600,000, PDI 1.9, <2 μm particle size, 4HB 10 wt%) having a solid content of 5% was distilled under reduced pressure to produce an aqueous dispersion having a solid content of 41%.

[0088] 99 parts of the 41% PHA aqueous dispersion prepared above was stirred at room temperature at 1500 rpm in a stirrer having a paddle or turbine type impeller, while 1 part of 10% dissolved polyvinyl alcohol (PVA, Kuraray, Mw 14,200, DH 88%) was added and stirred for 1 hour to prepare a coating solution.

[0089] That is, a composition containing 10% PHA solids and 0.24% PVA by weight was prepared.

[0090] Comparative Example 3 An aqueous dispersion of PHA (CJ CheilJedang, Mw 600,000, PDI 1.9, <2 μm particle size, 4HB 10 wt%) having a solid content was distilled under reduced pressure to prepare an aqueous dispersion having a solid content of 41%.

[0091] 95 parts of the 41% PHA aqueous dispersion prepared above was stirred at room temperature at 1500 rpm in a stirrer having a paddle or turbine type impeller, while 5 parts of 10% dissolved polyvinyl alcohol (PVA, Kuraray, Mw 14,200, DH 88%) was added and stirred for 1 hour to prepare a coating solution.

[0092] That is, a composition containing 10% PHA solids and 1.2% PVA by weight was prepared.

[0093] Comparative Example 4 An aqueous dispersion of PHA (CJ CheilJedang, Mw 600,000, PDI 1.9, <2 μm particle size, 4HB 10 wt%) having a solid content of 5% was distilled under reduced pressure to produce an aqueous dispersion having a solid content of 41%.

[0094] 98 parts of the 41% PHA aqueous dispersion prepared above was stirred at room temperature at 1500 rpm in a stirrer having a paddle or turbine type impeller, while 1 part of 10% dissolved polyvinyl alcohol (PVA, Kuraray, Mw 14,200, DH 88%) was added and stirred for 1 hour.

[0095] Then, 1 part of 5% gum arabic (ES food ingredient) dispersion was added and stirred for an additional 10 minutes to prepare a 40% PHA aqueous coating solution.

[0096] That is, a composition was prepared containing 10% PVA, 0.24% by weight and 5% gum arabic, 0.12% by weight on PHA solids.

[0097] Experimental Example 1 The compositions according to the examples and comparative examples were subjected to severe evaluation conditions (50°C, 2 weeks) to confirm the dispersion stability, and then the uncoated basis weight of 180 g / m 2 15g / m on Kraft paper 2 The coating was applied and dried at 170°C for 10 minutes to prepare a coated test piece.

[0098] The coating was done using a Mayer bar coater manufactured by RDS, and the water resistance was evaluated by measuring the Cobb value according to the TAPPI T 441 standard, with the test conditions being 10x10cm, 100mL, and 2min.

[0099] The results of the evaluation of dispersion stability are shown in Figure 1 for the Examples and in Figure 2 for the Comparative Examples. The results of the evaluation of water resistance are shown in Table 1. [Table 1]

[0100] As shown in Table 1, the compositions according to the examples exhibit excellent properties as paper coating solutions.

[0101] On the other hand, in the cases of Comparative Example 1, which contained no additive, Comparative Example 2, which contained no rheology modifier, Comparative Example 3, which used an excessive amount of additive, and Comparative Example 4, which used a gum arabic rheology modifier having spherical particles, it was confirmed that the physical properties were not suitable for paper coating.

[0102] As described above, the composition and method according to the present invention can simplify the manufacturing process of a PHA composition, minimize the amount of additives, and improve the physical properties of the composition to suit the intended use.

[0103] The above description is merely illustrative of the technical concept of the present invention, and those skilled in the art can make various modifications and variations without departing from the essential characteristics of the present invention.

[0104] Furthermore, the embodiments disclosed in the present invention are for illustrative purposes only and are not intended to limit the technical idea of ​​the present invention, and the scope of the technical idea of ​​the present invention is not limited by such embodiments. The scope of protection of the present invention should be interpreted according to the claims, and any technical idea within the scope equivalent thereto should be interpreted as being included in the scope of the rights of the present invention.

Claims

1. With respect to the total weight of the composition, 10 to 70% by weight of polyhydroxyalkanoic acid (PHA); less than 0.3% by weight of a surfactant or dispersant; and 0.5 wt. % or less of a rheology modifier; The PHA is Poly-3-hydroxybutyrate-co-4-hydroxybutyrate (P3HB-4HB), The content of 4HB in the PHA copolymer is 0.1 to 20%; The rheology modifier comprises one or more selected from the group consisting of gums, acrylics, urethanes, and epoxies; The PHA composition, wherein the particle shape of the gums is not spherical and is one or more selected from the group consisting of gellan gum, xanthan gum, carrageenan, curdlan gum, karaya gum, tragacanth gum, ghatti gum, algin, agar gum, and furcellaran.

2. The PHA composition described in claim 1, wherein the rheology modifier is contained in an amount of 0.3 weight percent or less based on the total weight of the composition.

3. 3. The PHA composition according to claim 1 or 2, wherein the molecular weight of the PHA is Mw 10,000 to 1,000,000.

4. The PHA composition according to claim 1 or 2, wherein the particle size of the PHA is 10 μm or less.

5. 3. The PHA composition of claim 1 or 2, wherein the surfactant comprises one or more selected from the group consisting of cationic, anionic, nonionic, and amphoteric surfactants.

6. A PHA composition described in claim 1 or 2, further comprising one or more selected from the group consisting of thickeners and antifoaming agents.

7. 3. The PHA composition of claim 1 or 2, wherein the dispersant comprises one or more selected from the group consisting of acrylic dispersants, urethane dispersants, epoxy dispersants, polyvinyl alcohol, and cellulose.

8. The PHA composition according to claim 7, wherein the molecular weight of the polyvinyl alcohol is Mw 10,000 to 200,000 and the degree of saponification is 80 to 99 mol%.

9. The coating amount of the composition is 10 g / m ２ 30g / m or more ２ The PHA composition according to claim 1 or 2,

10. The Cobb value of the composition is 3 g / m ２ 20g / m or more ２ The PHA composition according to claim 1 or 2,

11. 3. The PHA composition according to claim 1, wherein the composition is a coating composition for paper materials or polymeric film materials.

12. A method for producing the PHA composition according to claim 1 or 2, comprising the steps of: Producing a PHA aqueous dispersion; The dispersion is stirred. adding the surfactant or dispersant and the rheology modifier; A method for producing a PHA composition comprising the steps of:

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