Polyhydroxyalkanoate-containing multi-component water-based ink binder system, water-based ink composition and preparation method and application thereof

Abstract

The invention discloses a polyhydroxyalkanoate-containing multi-component water-based ink binder system, a water-based ink composition and a preparation method and application thereof, and belongs to the technical field of environment-friendly printing materials and water-based ink. According to the invention, a microscopic two-phase or core-shell structure taking the second film-forming resin as a continuous phase and polyhydroxyalkanoate as a dispersed and enriched phase is constructed. Compared with the prior art, a printing layer can be endowed with excellent anti-blocking property, smooth touch feeling and barrier property under an extremely thin dry film only by using an extremely small amount of bio-based components, and meanwhile, excellent adhesive force and abrasion resistance are ensured. In addition, the water-based ink composition also shows excellent household compost and industrial compost degradation performance. The system not only greatly reduces the cost, but also has excellent paper repulping and deinking characteristics, and provides a high-performance solution for environment-friendly printing.

Description

Technical Field

[0001] This invention belongs to the field of environmentally friendly printing materials and water-based ink technology, specifically involving a multi-component composite water-based ink binder system containing polyhydroxy fatty acid esters, water-based ink compositions, their preparation methods and applications. Background Technology

[0002] With increasingly stringent global environmental regulations and rising carbon emission reduction requirements, the printing ink industry is undergoing a profound transformation from traditional solvent-based systems to water-based and bio-based systems. While existing water-based inks significantly reduce volatile organic compound (VOC) emissions by using water instead of organic solvents, their main film-forming substances still heavily rely on petroleum-based polymers, such as waterborne acrylic resins, waterborne polyurethane (PUD), and vinyl resins. These synthetic resins are difficult to biodegrade in the natural environment after disposal, easily causing microplastic pollution, and often forming difficult-to-treat adhesive residues during paper recycling, affecting the quality and recycling efficiency of recycled paper.

[0003] To increase the bio-based content and impart biodegradable properties to ink systems, existing technologies have proposed various aqueous coating and ink solutions based on polyhydroxyalkanoates (PHA) or other biopolymer polyesters. For example, US Patent 5977250 discloses a PHA emulsion that can be used as a film-forming resin in coatings, adhesives, and printing inks. However, its system uses PHA as the main or sole film-forming phase and does not specify a second film-forming resin continuous phase or finely control anti-adhesion and tactile properties within a low PHA addition range. European Patent EP4166716A1 and its corresponding US Patent 11866606B2 disclose a biodegradable coating system based on an aqueous PHA dispersion for use as a waterproof and oil-resistant barrier layer in food contact packaging such as paper cups and cardboard. The PHA content in the dispersion is typically 25wt% to 65wt%, focusing on barrier performance and grease resistance at higher coating weights, but does not address anti-adhesion and tactile design at dry film thicknesses of 0.5 to 5 micrometers in flexographic or gravure aqueous ink systems. Chinese patent CN110475868B and others disclose PHA particles and their aqueous dispersions, and apply them to coatings, adhesives and composite materials. They also use PHA as the main continuous barrier phase and do not limit the two-phase structure design of the second film-forming resin continuous phase and the PHA dispersed enrichment phase.

[0004] In addition, earlier publications such as NL9401037A also reported aqueous dispersions of biodegradable polyester or PHA, which can be used in coatings, adhesives, and paper treatments. However, their focus was on the preparation and stability of the dispersions themselves, without systematically designing for the anti-blocking properties, tactile feel, and barrier properties of water-based inks at low coating weights. Meanwhile, biodegradable water-based ink binder systems without PHA have also been reported. For example, Chinese patent CN112375425A discloses a biodegradable water-based ink binder system with branched-chain starch modified liquid, polyvinyl alcohol resin liquid, and water-based polyamide as the main film-forming components. Other literature proposes a combination of water-based polyurethane and acrylic core-shell emulsions for use in biodegradable plastic film or paper printing. These solutions mainly rely on non-PHA bio-based components such as starch, polylactic acid (PLA), and polybutylene succinate (PBS) to improve degradability. The control of anti-adhesion and tactile properties is mostly achieved by adjusting the glass transition temperature of the resin or adding inert wax powder and inorganic fillers, without fully utilizing the potential of PHA crystalline phase in terms of anti-adhesion and tactile properties.

[0005] Recently, some companies and research institutions have further proposed technical routes such as fully bio-based PHA liquid bioplastic emulsions and reactive compatible acrylic resins with PHA core-shell latex. By using bio-based surfactants or acrylic compatible resins, PHA is stably dispersed in water in a high-solids or fully bio-based manner. These technologies are mostly used in resizing coatings, heat-sealing barrier coatings, adhesives, or paper-based functional coatings. However, the synergistic relationship between the continuous phase of the second film-forming resin and the dispersed and enriched phase of PHA in water-based ink formulations and their effects on printability, anti-blocking properties, and paper resizing and deinking performance have not been systematically discussed.

[0006] In summary, the printing and packaging industry urgently needs a new water-based ink binder system that can perfectly balance environmental performance and application performance. In particular, there is an urgent need for an environmentally friendly water-based ink binder product that can achieve excellent anti-blocking properties and a smooth feel at extremely thin dry film thicknesses, while maintaining high adhesion and abrasion resistance, good biodegradability, excellent re-inking and deinking performance, and is free of organic fluorine. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a multi-component composite waterborne ink binder system containing polyhydroxy fatty acid esters, waterborne ink compositions, their preparation methods and applications.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] This invention provides a PHA-containing multi-component aqueous ink binder system. The binder system is an aqueous dispersion comprising an aqueous dispersion medium and film-forming resin solids dispersed therein. The film-forming resin solids include at least a PHA component and a second film-forming resin component. The PHA component and the second film-forming resin component can exist respectively in the form of a PHA aqueous dispersion and a second film-forming resin aqueous dispersion or aqueous solution, and / or together in the form of latex particles constituting a core-shell structured composite emulsion. The solid component of the PHA aqueous dispersion is PHA or a copolymer thereof; the solid component of the second film-forming resin aqueous dispersion or aqueous solution is the second film-forming resin. Based on the total mass of the PHA and the second film-forming resin solids, the PHA accounts for 0.5-25 wt%, and the second film-forming resin accounts for 75-99.5 wt%. Specifically, the content of PHA can be 0.5wt%, 0.8wt%, 1.0wt%, 1.5wt%, 1.6wt%, 2.0wt%, 3.0wt%, 5.0wt%, 8.0wt%, 10.0wt%, 12.0wt%, 15.0wt%, 18.0wt%, 18.6wt%, 19.8wt%, 20.0wt%, 22.0wt%, 22.6wt%, 24.0wt%, or 25.0wt%, etc., and the content of the second film-forming resin can be 75.0wt%, 76.0wt%, 77.4wt%, 78.0wt%, 80.0wt%, 81.4wt%, 82.0wt%, 85.0wt%, 88.0wt%, 90.0wt%, 92.0wt%, 95.0wt%, 97.0wt%, 98.0wt%, 98.4wt%, 99.0wt%, 99.2wt%, or 99.5wt%, etc. Furthermore, after drying and film formation, the second film-forming resin forms a continuous phase, while PHA forms a dispersed and enriched phase. The second film-forming resin is selected from at least one of the following: aqueous acrylic resin emulsion or aqueous solution, aqueous polyurethane dispersion (PUD), aqueous vinyl resin emulsion, aqueous biodegradable polyester dispersion, aqueous dispersion or aqueous solution of natural polymer derivatives, and aqueous dispersion or aqueous solution of natural resins and their modifiers.

[0010] In the binder system, the PHA is selected from short-chain PHA, medium- and long-chain PHA, or copolymers between monomers forming short-chain and medium- and long-chain PHA. The short-chain PHA is selected from one or more of the following short-chain PHAs: poly(3-hydroxybutyrate) (PHB), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), and poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P(3HB-co-4HB)). The medium- and long-chain PHA is selected from homopolymers or copolymers obtained by polymerizing 3-hydroxy fatty acid monomers with 6-16 carbon atoms, wherein the 3-hydroxy fatty acid monomers are selected from one or more of 3-hydroxyhexanoic acid, 3-hydroxyheptanoic acid, 3-hydroxyoctanoic acid, 3-hydroxynonanoic acid, 3-hydroxydecanoic acid, 3-hydroxyundecanoic acid, 3-hydroxydodecanoic acid, 3-hydroxytetradecanoic acid, and 3-hydroxyhexadecanoic acid, for example, poly(3-hydroxybutyrate-co-3-hydroxyhexanoic acid) (PHBH).

[0011] In the binder system, the second film-forming resin is a polymer or mixture thereof polymerized from one or more of the following monomers: acrylic acid, methacrylic acid, and acrylate and methacrylate monomers obtained by esterification of C1-C8 linear or branched alcohols, including methyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, and butyl methacrylate; styrene and its substituted monomers, including styrene, α-methylstyrene, and vinyltoluene; ethylene and vinyl ester monomers, including ethylene, vinyl acetate, and auxiliary monomers used for copolymerization with other vinyl monomers to form ethylene-vinyl acetate copolymers, polyvinyl acetate, and other vinyl copolymers; and polyurethane obtained by polycondensation of diisocyanate monomers and polyol monomers, wherein the diisocyanate monomers are selected from isophorone diisocyanate and hexamethylene diisocyanate. The film-forming resin comprises one or more of toluene diisocyanate and diphenylmethane diisocyanate, and the polyol monomer is selected from one or more of polyester polyol, polyether polyol, and polycarbonate polyol; biodegradable polyesters obtained by polycondensation of dicarboxylic acid monomers and diol monomers, including PLA, PBAT, PBS and their copolymers obtained by polycondensation of one or more of lactic acid, glycolic acid, succinic acid, adipic acid, and terephthalic acid with one or more of ethylene glycol, propylene glycol, and butanediol; natural polymer derivatives and natural resin modifiers, including starch or its etherified or esterified derivatives composed of glucose repeating units, cellulose and its carboxymethyl or hydroxyethyl derivatives composed of β-glucose repeating units, rosin resins based on rosin acid and its adducts and their salts or esters, and polymers based on soybean protein or other plant proteins that have been cross-linked or grafted modified. The second film-forming resin is used to prepare water-based ink binders to provide a continuous film-forming phase at a dry film thickness of 0.5-5 μm. The specific dry film thickness can be 0.5μm, 0.8μm, 1.0μm, 1.2μm, 1.5μm, 2.0μm, 2.5μm, 3.0μm, 3.5μm, 4.0μm, 4.5μm or 5.0μm, etc.

[0012] The binder system further comprises an interface compatibilizer or a reactive coupling agent. Based on the total solid mass of the PHA and the second film-forming resin, the amount of the interface compatibilizer or reactive coupling agent added is 0.05-10 wt%. Specific addition amounts can be 0.05 wt%, 0.1 wt%, 0.2 wt%, 0.5 wt%, 0.8 wt%, 1.0 wt%, 1.5 wt%, 2.0 wt%, 3.0 wt%, 5.0 wt%, 6.0 wt%, 8.0 wt%, or 10.0 wt%, etc. The interface compatibilizer or reactive coupling agent is selected from at least one of the following: block copolymers or graft copolymers containing hydrophilic and hydrophobic segments; polymer dispersants; reactive coupling components containing epoxy, carboxyl, hydroxyl, isocyanate, carbodiimide, or aziridinium groups.

[0013] The binder system satisfies one or more of the following physical properties or structural characteristics: pH at 25°C is 7.0-10.0, specifically 7.0, 7.2, 7.5, 7.8, 8.0, 8.1, 8.2, 8.5, 8.8, 9.0, 9.5, or 10.0; total solids content is 15-60 wt%, specifically 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 38 wt%, 39 wt%, 40 wt%, 41.5 wt%, 42.0 wt%, 42.5 wt%, 43.0 wt%, 43.5 wt%, 44.0 wt%, 44.2 wt%, 45 wt%, 50 wt%, 55 wt%, or 60 wt%; and the volume distribution particle size D measured by dynamic light scattering or laser diffraction is [not specified]. 50 The particle size ranges from 0.2 μm to 2.0 μm, with specific particle size D... 50 The micrometer size can be 0.2μm, 0.25μm, 0.28μm, 0.3μm, 0.35μm, 0.4μm, 0.5μm, 0.6μm, 0.8μm, 0.9μm, 1.0μm, 1.2μm, 1.3μm, 1.5μm, 1.8μm, 1.9μm, or 2.0μm, etc. After drying and film formation, a two-phase or multi-phase structure is formed, comprising a PHA-enriched phase and a second film-forming resin continuous phase. The PHA-enriched phase forms discrete phase domains, and the average characteristic size of these discrete phase domains is 0.2μm-2.0μm. Specifically, the average characteristic size can be 0.2μm, 0.25μm, 0.3μm, 0.4μm, 0.5μm, 0.8μm, 1.0μm, 1.2μm, 1.5μm, 1.8μm, or 2.0μm, etc.

[0014] The binder system comprises a core-shell structured composite emulsion, wherein: the latex particles of the core-shell structured composite emulsion include a PHA-containing core layer and a shell polymer coating thereon; the polymer solid of the core layer contains PHA or a copolymer thereof; and the polymer solid of the shell layer contains at least one of acrylic resin, polyurethane resin, vinyl resin, or biodegradable polyester resin; the latex particles of the core-shell structured composite emulsion satisfy the volume distribution particle size D measured by dynamic light scattering or laser diffraction. 50 The particle size ranges from 0.2 μm to 2.0 μm, and based on the total mass of the polymer solids in the core and shell layers, the core layer accounts for 5-40 wt%, and the shell layer accounts for 60-95 wt%. Specifically, the core layer percentage can be 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, or 40 wt%, etc., and the shell layer percentage can be 95 wt%, 90 wt%, 85 wt%, 80 wt%, 75 wt%, 70 wt%, 65 wt%, or 60 wt%, etc.

[0015] The shell polymer is a polymer or mixture thereof polymerized from one or more of the following monomers, and the glass transition temperature (Tg) of the shell polymer is -40 to 120°C. Specifically, the Tg can be -40°C, -20°C, 0°C, 10°C, 20°C, 21°C, 25°C, 28°C, 30°C, 40°C, 50°C, 60°C, 80°C, 100°C, or 120°C. The polymers include: copolymers formed from acrylic acid, methacrylic acid and their C1-C8 alkyl ester monomers, or copolymers formed from acrylic acid, methacrylic acid and their C1-C8 alkyl ester monomers and styrene monomers; aliphatic or aromatic polyurethanes obtained by polycondensation of isophorone diisocyanate, hexamethylene diisocyanate, toluene diisocyanate or diphenylmethane diisocyanate with polyester polyol, polyether polyol or polycarbonate polyol; ethylene-vinyl acetate copolymers, polyvinyl acetate or other vinyl copolymers formed from ethylene and vinyl acetate and other vinyl monomers used for copolymerization; PLA, PBAT, PBS or copolymers thereof obtained by polycondensation of one or more of lactic acid, glycolic acid, succinic acid, adipic acid, terephthalic acid with one or more of ethylene glycol, propylene glycol, butanediol; optionally, monomers containing carboxyl, hydroxyl, epoxy, urethane or carbodiimide groups are introduced into the shell polymer during copolymerization.

[0016] Based on the total mass of the film-forming resin solids in the binder system, the core-shell composite emulsion provides 10-60 wt% of the film-forming resin, and the second film-forming resin provides 40-90 wt%. Specifically, the proportion of film-forming resin provided by the core-shell composite emulsion can be 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, or 60 wt%, etc., and the proportion of the second film-forming resin can be 90 wt%, 85 wt%, 80 wt%, 75 wt%, 70 wt%, 65 wt%, 60 wt%, 55 wt%, 50 wt%, 45 wt%, or 40 wt%, etc.

[0017] This invention also provides an aqueous ink composition comprising the above-mentioned binder system, pigment, and aqueous medium; by weight, based on 100 parts by total weight of the aqueous ink composition, it comprises the following components: the binder system, as an aqueous dispersion, 30-70 parts, specifically 30, 35, 40, 45, 50, 55, 60, 65, or 70 parts; pigment or pigment paste containing pigment, specifically 8, 10, 12, 15, 18, 20, 22, 25, 28, or 30 parts; additives, specifically 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 7, or 8 parts; and the balance being the aqueous medium; wherein, based on dry solids and according to EN... 14582:2016 The total fluorine content determined by closed-system oxygen bomb combustion-ion chromatography is less than 5 mg / kg.

[0018] In the water-based ink composition, the additives include at least one or more of wetting and dispersing agents, defoamers, and leveling agents; optionally, the water-based ink composition further includes a bio-based plasticizer selected from one or more of acetylacetic tributyl citrate (ATBC), other citrate plasticizers, epoxidized vegetable oils, polyester plasticizers, or glycerides.

[0019] The water-based ink composition satisfies at least one of the following: a total solids content of 30-60 wt%, specifically 30 wt%, 35 wt%, 38.0 wt%, 39.0 wt%, 40.0 wt%, 41.5 wt%, 42.0 wt%, 42.5 wt%, 43.0 wt%, 43.5 wt%, 44.0 wt%, 44.2 wt%, 45 wt%, 50 wt%, 55 wt%, or 60 wt%; and a fineness ≤10 μm, specifically 10 μm, 9 μm, 8.5 μm, 8 μm, 7 μm, 6 μm, 5.0 μm, 4.2 μm, 4.0 μm, 3.8 μm, 3.5 μm, 3.2 μm, 3.0 μm, 2.8 μm, 2.0 μm, or 1.0 μm.

[0020] The water-based ink composition meets the biodegradation and disintegration requirements of industrial composting standard EN 13432 or household composting standard AS 5810, with a biodegradation rate greater than 90% within 180 days under controlled composting conditions. Specific biodegradation rates can be 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%.

[0021] The present invention also provides a method for preparing the above-mentioned water-based ink composition, comprising the following steps:

[0022] Step 1. Prepare a composite binder system containing PHA and a second film-forming resin under all-aqueous conditions. This step is achieved through one or a combination of the following methods: physically mixing a PHA aqueous dispersion with a pH adjusted to 7.5-8.5 with a second film-forming resin aqueous dispersion or aqueous solution in an aqueous medium in proportion; or performing in-situ emulsion polymerization of the monomers of the second film-forming resin in the presence of the PHA aqueous dispersion, with water as the continuous phase, wherein the monomers are pre-emulsified in water and then added to form a second film-forming resin aqueous dispersion; when an interfacial compatibilizer or reactive coupling agent is present, it is added during the preparation of the PHA aqueous dispersion or the second film-forming resin aqueous dispersion, during the physical mixing or in-situ emulsion polymerization, or after the composite binder system is prepared, to obtain the composite binder system.

[0023] Step 2. In the presence of a wetting and dispersing agent, the colorant is ground or dispersed at high speed with a portion of the aqueous medium until the target fineness and particle size distribution are achieved, thus obtaining a color paste;

[0024] Step 3. Under stirring conditions, the color paste is added to the composite binder system obtained in Step 1, and other additives and remaining aqueous media are added in sequence. The viscosity and pH are adjusted, and the mixture is filtered to obtain an aqueous ink composition.

[0025] In the preparation method, the in-situ emulsion polymerization in step one includes: in the presence of PHA latex seeds, emulsion polymerization is carried out with water as the continuous relative shell monomer. The shell monomer is added after aqueous emulsification under controlled dropping rate and temperature to obtain a core-shell structured composite emulsion.

[0026] The present invention also relates to the application of the water-based ink composition, which is used for flexographic printing, gravure printing or screen printing, in the form of surface printing or reverse printing, to form an ink image layer on the surface or inner layer of the substrate, wherein the dry film thickness of the ink image layer is 0.5-5 μm; the substrate includes paper, cardboard, polyester film, including polyethylene terephthalate (PET) film and biodegradable polyester film, or surface-treated polyolefin film, such as biaxially oriented polypropylene film (BOPP).

[0027] The present invention also provides a printing layer, which is formed by applying the water-based ink composition by flexographic printing, gravure printing or screen printing and drying and curing. The printing layer includes a continuous phase formed by a second film-forming resin and PHA-enriched phase particles dispersed in the continuous phase, and the dry film thickness of the printing layer is 0.5-5 μm.

[0028] Compared with the prior art, the following significant advantages can be obtained by using the present invention:

[0029] The binder system of the present invention effectively solves the problem that bio-based resins are difficult to balance in terms of film-forming properties and functionality at extremely thin dry film thicknesses (0.5-5 μm) by introducing PHA as a dispersed enriched phase or core layer at a specific ratio of 0.5-25 wt% and using a second film-forming resin as a continuous phase or shell layer.

[0030] This system utilizes the crystallization properties of PHA to significantly improve the anti-blocking properties and smooth feel of the printed layer while ensuring excellent adhesion and abrasion resistance of the continuous phase. It is suitable for high-speed printing processes such as flexographic printing.

[0031] The water-based ink composition of the present invention maintains high performance while possessing good biodegradability and excellent paper repulping and deinking performance. Furthermore, no organic fluorides are intentionally added in the formulation design, which meets strict environmental protection and safety standards. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the microscopic cross-sectional structure of the water-based ink composition of the present invention after drying and forming a film on a printing substrate.

[0033] In the figure, 1-substrate; 2-printing layer; 3-pigment; 4-dispersed and enriched phase particles formed by polyhydroxyalkanoates; 5-continuous phase formed by the second film-forming resin; 6-core layer (containing polyhydroxyalkanoates); 7-shell layer (containing the second film-forming resin). Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention. Unless otherwise stated, the raw materials used in this embodiment are commercially available industrial products or can be prepared by conventional methods. Unless otherwise specified, performance testing methods are performed according to the standards described in the invention summary section.

[0035] This figure is a schematic diagram of the microscopic cross-sectional structure of the water-based ink composition according to an embodiment of the present invention after drying and forming a film on a printing substrate. In the figure, mark 1 represents the printing substrate; mark 2 above it represents the entire printed layer after drying and curing. The printed layer 2 uses a continuous phase formed by the second film-forming resin shown in mark 5 as the matrix, in which the pigment shown in mark 3 and the dispersed enriched phase particles formed by polyhydroxyalkanoates shown in mark 4 are dispersed. The dispersed enriched phase particles 4 exhibit a core-shell structure, where mark 6 represents the core layer (containing polyhydroxyalkanoates) located at the center; mark 7 represents the shell layer (containing the second film-forming resin) surrounding the core layer.

[0036] Main reagents and raw materials:

[0037] Table 1. Names, specifications or models, and manufacturers of major reagents and raw materials:

[0038]

[0039] Note: The particle size D listed in Table 1 50 The median diameter of the volume distribution was measured at 25°C. For small-diameter samples, dynamic light scattering was used, and for large-diameter samples, laser diffraction was used. Unless otherwise stated, "pigment paste" as used herein refers to the aqueous pigment paste prepared according to this example. "Additives" as used herein include wetting and dispersing agent BYK-190, defoamer BYK-024, and leveling agent BYK-333, premixed in a 2:1:1 mass ratio as an additive package.

[0040] Main analytical and testing instruments:

[0041] Table 2 mainly analyzes the names, brands or models, and manufacturers of the testing instruments:

[0042]

[0043] Main testing standards and methods:

[0044] Fineness: The fineness of ink was determined in accordance with GB / T 13217.3-2022 "Test Method for Fineness of Ink".

[0045] Viscosity: The viscosity was determined in accordance with GB / T 13217.4-2020 "Ink Viscosity Test Method"; the outflow cup viscosity was expressed as the outflow time (seconds) measured by a Ford-4 viscosity cup (according to GB / T 1723-1993 Method B, Dimensions and Operation) at 25.0±0.2℃; the rotational viscosity was measured by a Brookfield DV2T at 25.0±0.1℃ and the rotor model and speed were recorded.

[0046] Gloss: Refer to GB / T 13217.2-2024 "Ink Gloss Test Method", the test angle is 60 degrees.

[0047] Adhesion: The adhesion was tested in accordance with GB / T 13217.7-2023 "Test Method for Adhesion of Ink".

[0048] Anti-blocking property: Tested according to GB / T 13217.8-2009 "Test Method for Anti-blocking of Liquid Inks", with test conditions set as follows: temperature 50℃, load 5kg, and pressing time 24h. After the test, the separation was evaluated using a scoring system of 1 to 5 points: 5 points indicates no sticking and no surface damage after separation; 4 points indicates slight sticking but can be separated without damage; 3 points indicates moderate sticking and slight surface marks after separation; 2 points indicates significant sticking and significant surface damage after separation; 1 point indicates severe sticking or inability to separate without damage.

[0049] Abrasion resistance: Friction test was conducted in accordance with GB / T 7706-2008 "Relief Printing". A friction testing machine was used, with a standard weight of 4 pounds (1.81 kg) as the load, standard cotton cloth as the friction medium, 100 cycles of reciprocating friction, and a friction speed of 42 times / min. After the test, the wear or exposure of the graphic layer was graded using a 1 to 5-point scoring system: 5 points indicates almost no wear, 4 points indicates slight wear, 3 points indicates moderate wear, 2 points indicates significant wear, and 1 point indicates severe wear or exposure of the background.

[0050] Water droplet contact angle: The test was conducted in accordance with GB / T 30693-2014 "Measurement of contact angle between plastic film and water". The test conditions included a drop volume of 3 to 5 μL, an ambient temperature of 23±2℃, and data were read 5 to 10 seconds after the drop was added and the average value of at least 5 points was taken.

[0051] The barrier performance, i.e., the oxygen permeability (OTR), was conducted in accordance with GB / T 1038.2-2022 "Test Methods for Gas Permeability of Plastic Films and Sheets Part 2: Isobaric Method". The test temperature was 23.0℃ and the relative humidity was 0%RH. The test sample was a substrate with a printed layer facing the oxygen side. The results were compared under the same instrument and conditions and converted according to the standard and expressed as cm³ / (m²·d).

[0052] Total solids content: determined according to ISO 3251:2019.

[0053] Repulping performance: Determined according to Cepi's laboratory test method for paper and paperboard recyclability (Version 3, February 2025).

[0054] Deinking performance: Tested in accordance with ISO 21993:2020.

[0055] Total fluorine content: Referring to EN 14582:2016, which is the method for determining halogen content after combustion of oxygen bomb in a closed system, this patent uses oxygen bomb combustion combined with ion chromatography for total fluorine screening.

[0056] Industrial composting performance: Test procedures and evaluation criteria for packaging materials for composting and biodegradation recycling were performed in accordance with EN 13432:2000 "Requirements for composting and biodegradation recycling of packaging materials – Test protocols and evaluation criteria for final acceptance" and ISO 14855-1:2012 "Determination of final aerobic biodegradation capacity of materials under controlled composting conditions – Analysis of carbon dioxide release – Part 1: General methods". The test temperature was 58±2℃, and the test period was 180 days.

[0057] Home composting performance: Tested according to AS 5810-2010 "Biodegradable plastics - Plastics suitable for home composting". The test temperature was 25±5℃, and the test period was 180 to 360 days.

[0058] Particle size D 50 The dispersion or binder system was diluted with deionized water to a solids content of 0.01 to 0.05 wt%, and measured at 25°C. D 50 The median diameter refers to the volume distribution. For small-diameter samples, dynamic light scattering is used for determination, while for large-diameter samples, laser diffraction is used for determination.

[0059] Dry film thickness: After preparing samples using the same printing process, the dry film thickness is controlled and confirmed using cross-sectional microscopy or a weighing-based conversion algorithm. The weighing-based conversion algorithm calculates the dry film thickness h = Δm / (A·ρ) based on the mass difference Δm before and after printing, the effective printing area A, and the dry film density ρ, where ρ can be estimated according to the formula or obtained through density testing. The typical thickness in this patent is 2 to 3 μm or 2.0 μm.

[0060] Touch rating: Samples were placed in an environment of 23±2℃ and 50±10%RH for 24 hours before testing. No fewer than 3 reviewers touched the surface of the sample 3 times in the same direction with their fingertips under blind testing conditions and scored it. A scoring system of 1 to 5 points was used and the average value was taken (retaining 1 decimal place). Among them, 5 points indicates obvious smoothness and no stickiness, 4 points indicates smoothness and only slight stickiness, 3 points indicates moderate smoothness and stickiness, 2 points indicates insufficient smoothness and obvious stickiness, and 1 point indicates obvious stickiness and rough touch.

[0061] Characterization of two-phase or core-shell structures: The printed sample was subjected to liquid nitrogen brittle fracture or frozen sectioning to obtain cross sections. The morphology of the PHA-enriched phase or core layer and continuous phase was observed using a scanning electron microscope. The characteristic size distribution of the discrete phase domain was statistically analyzed by threshold segmentation or equivalent methods on the cross section images, and the average characteristic size and distribution range were recorded.

[0062] General preparation process:

[0063] Preparation Example 1: General preparation method of PHA aqueous dispersion:

[0064] Applicable to: PHBV aqueous dispersion, PHBH aqueous dispersion, PHB aqueous dispersion.

[0065] Step 1. Taking the preparation of an aqueous dispersion with a solid content of 35 wt% as an example, add 185 parts by mass of deionized water, 1.0 parts by mass of sodium dodecyl sulfate (SDS) and 2.0 parts by mass of polyvinyl alcohol (PVA, grade 1788) to a high-speed dispersion vessel and stir until completely dissolved; add 100 parts by mass of PHA resin powder in batches at 30℃ and perform high-speed shear pre-dispersion at a speed of 6000 r / min for 20 min to obtain PHA premixed solution.

[0066] Step 2. The PHA premixed liquid is transferred into a high-pressure homogenizer and homogenized 7 times at 70 MPa pressure; jacket cooling is used during homogenization to control the liquid temperature at 40°C; particle size is monitored by dynamic light scattering method, and the particle size D of the PHBV aqueous dispersion is controlled. 50 The controlled particle size D of PHBH aqueous dispersion is 200 nm. 50 The controlled particle size D of the PHB aqueous dispersion is 250 nm. 50 The target particle size is 300 nm, and homogenization is stopped when the target particle size is reached.

[0067] Step 3. Adjust the pH of the dispersion to 7.5 to 8.5 with 10wt% sodium hydroxide aqueous solution or ammonia; after discharge, filter through a 100 to 200 mesh filter to remove a small amount of undispersed particles to obtain a general-purpose PHA aqueous dispersion.

[0068] General preparation method of PHA latex seeds:

[0069] Applicable to: PHBV latex lower particle size limit seeds, PHBV latex medium particle size seeds, and PHBV latex upper particle size limit seeds.

[0070] Step 1. Disperse PHA resin powder in deionized water containing 0.5-2.0 wt% sodium dodecyl sulfate (SDS) and 0.5-3.0 wt% polyvinyl alcohol (PVA) (all percentages are based on the mass of the resin powder). Perform preliminary dispersion using a shear emulsifier (3000-8000 r / min, 10-30 min) to obtain PHA seed premix.

[0071] Step 2. The PHA seed premix solution is processed in a high-pressure homogenizer. The final particle size is controlled by adjusting the homogenization pressure and the number of cycles. When D is required... 50 When the lower limit seed size is 0.2 μm, the homogenization pressure is 70-80 MPa and the cycle is 6-10 times; when it is necessary to obtain D 50 For medium-sized seeds (approximately 0.9 μm), the homogenization pressure is 50-70 MPa, and the cycle is 3-6 times; when it is necessary to obtain D... 50When the upper limit of the seed size is about 1.3μm, the homogenization pressure is 40-60MPa and the cycle is 1-3 times. After confirming the particle size by dynamic light scattering or laser diffraction, the material is discharged and filtered to obtain PHA latex seeds.

[0072] Preparation method of PHA coarse particle suspension:

[0073] Applicable to: PHBV coarse particle suspension.

[0074] Step 1. Add PHA resin powder to deionized water, and add a small amount of wetting agent, such as wetting and dispersing agent BYK-190, in an amount of 0.1 to 0.5 wt% based on the weight of the resin powder, to obtain a PHA solid-liquid mixture.

[0075] Step 2. The PHA solid-liquid mixture is stirred and dispersed for 30 minutes using a conventional mechanical stirrer, without high-pressure homogenization to maintain the original particle morphology of the resin, resulting in a solid content of 30 wt% and a particle size D. 50 It is a suspension of coarse PHA particles with a diameter of 12.5 μm.

[0076] Preparation method of PBAT aqueous dispersion:

[0077] Applicable to: PBAT aqueous dispersions.

[0078] Step 1. Taking the preparation of an aqueous dispersion with a solid content of 45 wt% as an example, PBAT resin is dissolved in a volatile organic solvent such as ethyl acetate or acetone to obtain a PBAT organic phase with a PBAT mass fraction of 20 to 40 wt%. The aqueous phase containing emulsifier is emulsified with the organic phase under high-speed shear conditions at a speed of 8000 to 12000 r / min for 5 to 15 min to obtain a PBAT emulsion. The emulsifier is sodium dodecyl sulfate (SDS) with an amount of 0.5 to 2.0 wt% based on the mass of PBAT resin.

[0079] Step 2. Remove the organic solvent from the PBAT emulsion by vacuum distillation or rotary evaporation at 40 to 60°C, and continue removal under a final vacuum of -0.08 to -0.095 MPa until the residual solvent content is below 0.1 wt%. Then, add or concentrate with deionized water to achieve the target solid content of 45 wt%, and filter through a 100 to 200 mesh filter to obtain a particle size D. 50 It is a 450nm PBAT aqueous dispersion.

[0080] General preparation method of water-based pigments:

[0081] Applicable to: blue pigment paste, carbon black pigment paste.

[0082] Step 1. By weight, add 55 to 70 parts of deionized water and 2 to 6 parts of wetting and dispersing agent to a high-speed shear disperser. After stirring evenly, slowly add 25 to 45 parts of colorant, such as blue pigment or carbon black pigment, and perform high-speed shear pre-dispersion at a speed of 8000 to 12000 r / min for 10 to 20 min to obtain a pre-dispersed slurry.

[0083] Step 2. Transfer the pre-dispersed slurry to a sand mill, using 0.3 to 0.5 mm zirconia grinding beads, and circulate and grind for 30 to 90 minutes; control the slurry temperature not to exceed 45℃ during grinding. Use a fineness of ≤10 μm as the endpoint, as measured by GB / T 13217.3-2022, and record the pH and viscosity of the pigment.

[0084] Step 3. Add or concentrate the color paste to the target solid content with deionized water, and filter it through a 100 to 200 mesh filter to obtain an aqueous color paste.

[0085] Example:

[0086] Example 1:

[0087] Formula by weight: 1 part of PHBV aqueous dispersion with 35wt% solids, 47 parts of acrylic emulsion with 46wt% non-volatiles, 20 parts of pigment paste, 3 parts of additives, and 29 parts of deionized water.

[0088] Preparation method: PHBV aqueous dispersion is mixed into acrylic emulsion as an additive. Under all-aqueous conditions, the color paste is ground, the auxiliary agent and the remaining aqueous medium are added, the pH is adjusted to 8.0 and filtered to obtain an aqueous ink composition.

[0089] In this formulation, the mass ratio of PHA to acrylic resin after dry weight is 1.6:98.4.

[0090] Example 2:

[0091] Formula by weight: 50 parts acrylic emulsion, 15 parts PHBH aqueous dispersion, 25 parts pigment paste, 4 parts film-forming aid, 2 parts auxiliary agent, and 4 parts deionized water.

[0092] Preparation method: Under stirring conditions, acrylic emulsion and PHBH aqueous dispersion are mixed evenly to obtain a mixed emulsion; after preparing pigment paste in the presence of wetting and dispersing agent, it is added to the mixed emulsion, followed by film-forming aid and auxiliary agent; after mixing evenly, the pH is adjusted to 8.2 with 10wt% sodium hydroxide aqueous solution, and the flow time of the Ford-4 viscosity cup at 25°C is adjusted to 23 seconds with deionized water, and the water-based ink composition is obtained by filtration.

[0093] Example 3:

[0094] Formula by weight: 45 parts of waterborne polyurethane dispersion with approximately 40 wt% non-volatile components, 15 parts of poly(3-hydroxybutyrate) (PHB) water dispersion, 20 parts of black pigment paste, 2 parts of wax emulsion with approximately 25 wt% non-volatile components, 2 parts of additives, and 16 parts of deionized water.

[0095] Preparation method: The aqueous polyurethane dispersion and the PHB aqueous dispersion were mixed in a stirring container, and then black pigment paste and wax emulsion were added. After thorough mixing, the additives and the remaining deionized water were added. The pH was adjusted to 8.1 with 10wt% sodium hydroxide aqueous solution, and the flow time of the Ford-4 viscosity cup at 25°C was adjusted to 26 seconds with deionized water. The aqueous ink composition was obtained by filtration.

[0096] Example 4:

[0097] Core-shell emulsion preparation: 200g of PHBV aqueous dispersion and 350g of deionized water were added to a 2L four-necked glass reactor. 3.0g of SDS and 2.0g of PVA were added, and the mixture was mechanically stirred at 500 rpm. After nitrogen purging for 30 minutes, the temperature was raised to 78℃. 210g of a monomer mixture of methyl methacrylate (MMA), butyl acrylate (BA), and acrylic acid (AA) in a mass ratio of 60:35:5 was added to 150g of deionized water and 2.0g of SDS. Pre-emulsification was performed at a high-speed shearing speed of 10000 r / min for 8 min to obtain a monomer pre-emulsion. Separately, 1.5 g of APS was dissolved in 20 g of deionized water to prepare an initiator solution, which was added to the reactor at 78 °C and the monomer pre-emulsion was added dropwise at a constant rate over 2.5 hours. After the addition was completed, polymerization was maintained at this temperature for 1 hour. After the reaction was completed, the temperature was lowered to 35 °C, and the pH of the emulsion was adjusted to 8.0 with a 10 wt% sodium hydroxide aqueous solution. The emulsion was then filtered through a 150-mesh filter to obtain a core-shell composite emulsion.

[0098] Ink formulation: 50 parts of the above-mentioned core-shell emulsion, 25 parts of pigment paste, 3 parts of additives, and 22 parts of deionized water.

[0099] Preparation method: The prepared core-shell structured composite emulsion is placed in a stirring tank, and pre-ground pigment paste is added and stirred evenly; then, additives and deionized water are added, the viscosity is adjusted to a suitable printing range, and the material is filtered out to obtain a water-based ink composition.

[0100] In this core-shell emulsion, the volume distribution particle size D was measured by dynamic light scattering. 50 The core diameter is 280 nm, and the core-shell mass ratio is 25:75 based on the total mass of the core and shell polymer solids. The glass transition temperature (Tg) of the shell polymer, determined by differential scanning calorimetry, is 28 °C.

[0101] Example 5:

[0102] Core-shell emulsion preparation: using D50 Using 200g of 0.2μm PHBV latex as seed, a core-shell composite emulsion was prepared by referring to the core-shell emulsion polymerization process and monomer ratio of Example 4, i.e., MMA:BA:AA = 60:35:5. The amount of monomer mixture was adjusted to 240g, and the amount of initiator ammonium persulfate (APS) was adjusted to 1.7g, accounting for about 0.7wt% of the monomer mass. The dropping time, temperature, stirring and post-treatment conditions were the same as in Example 4.

[0103] Ink formulation: 50 parts of the core-shell emulsion, 25 parts of pigment paste, 3 parts of additives, and 22 parts of deionized water.

[0104] Preparation method: Same as in Example 4.

[0105] In this system, the core-shell solid mass ratio is 20:80, and the volume distribution particle size D was measured by dynamic light scattering method. 50 It is 0.35μm.

[0106] Example 6:

[0107] Core-shell emulsion preparation: using D 50 Using 200g of 1.3μm PHBV latex as seed, a core-shell composite emulsion was prepared by referring to the core-shell emulsion polymerization process and monomer ratio of Example 4, i.e., MMA:BA:AA = 60:35:5. The amount of monomer mixture was adjusted to 180g, and the amount of ammonium persulfate (APS) was adjusted to 1.3g, accounting for about 0.7wt% of the monomer mass. The dropping time, temperature and post-treatment conditions were the same as in Example 4.

[0108] Ink formulation: 50 parts of the core-shell emulsion, 25 parts of pigment paste, 3 parts of additives, and 22 parts of deionized water.

[0109] Preparation method: Same as in Example 4.

[0110] D was measured in this system 50 The core-shell solid mass ratio is 25:75, and the PHA solid content is 25 wt%.

[0111] Example 7:

[0112] Formula by weight: 10 parts PHBH aqueous dispersion, 20 parts sodium carboxymethyl starch (CMS-Na) aqueous solution, 20 parts acrylic emulsion, 0.5 parts water-based carbodiimide crosslinking agent, 25 parts pigment paste, 5 parts ATBC, 3 parts additives, and 16.5 parts water.

[0113] Preparation method: PHBH aqueous dispersion, CMS-Na aqueous solution, and acrylic emulsion were mixed evenly at 25°C to obtain a mixed resin solution; an aqueous carbodiimide crosslinking agent was added, and the mixture was reacted for 30 minutes under stirring; then pigment paste, ATBC, and additives were added, and stirring was continued until homogeneous. If necessary, the pH of the system was adjusted to 7.5 to 8.5 with a 10wt% sodium hydroxide aqueous solution and filtered to obtain an aqueous ink composition. The amount of aqueous carbodiimide crosslinking agent added was 0.8wt% based on the total mass of the film-forming resin solids.

[0114] Example 8:

[0115] Formula by weight: 0.44 parts PHBV aqueous dispersion, 66.3 parts acrylic emulsion, 20 parts pigment paste, 3 parts additives, and 10.26 parts deionized water.

[0116] Preparation method: PHBV aqueous dispersion is physically blended into acrylic emulsion; pre-prepared pigment paste is added and stirred to disperse evenly; additives and deionized water are added in sequence, pH value and viscosity are adjusted, and the mixture is filtered to obtain water-based ink composition.

[0117] PHA accounts for 0.5 wt% of the total solid mass of the film-forming resin.

[0118] Example 9:

[0119] Formula by weight: 15 parts PHBV aqueous dispersion, 34.6 parts styrene-acrylic emulsion with 45.5 wt% non-volatile content, 20 parts pigment paste, 3 parts additives, and 27.4 parts deionized water.

[0120] Preparation method: PHBV aqueous dispersion and styrene-acrylic emulsion are mixed in a stirred tank; pigment paste is added and dispersed evenly at high speed; additives and deionized water are added, the pH is adjusted to about 8.0 and filtered to obtain water-based ink composition.

[0121] After conversion to dry weight, the mass ratio of PHA to the second film-forming resin is 25:75.

[0122] Example 10:

[0123] Core-shell emulsion preparation: using D 50200g of medium-sized PHBV latex seeds (0.9μm, 30wt% solids content) were used as seeds. In a 2L four-necked glass reactor, 200g of the seed emulsion and 350g of deionized water were added, along with 3.0g of SDS and 2.0g of PVA. The mixture was mechanically stirred at 300-600 rpm and purged with nitrogen for 30 minutes before being heated to 75-80°C. 90g of a monomer mixture (MMA, BA, AA) prepared in a mass ratio of 60:35:5 was added, along with 65g of deionized water and 0.9g of SDS. DS was pre-emulsified under high-speed shear at 8000-12000 r / min for 5-10 min to obtain a monomer pre-emulsion. Separately, 0.65 g of APS was dissolved in 15 g of deionized water to prepare an initiator solution, which was added to the reactor at 75-80°C. The monomer pre-emulsion was then added dropwise at a constant rate over 2-3 hours. After the addition was complete, polymerization was maintained at this temperature for 1 hour. After the reaction, the temperature was lowered to below 40°C, and the pH of the emulsion was adjusted to 7.5-8.5 with a 10 wt% sodium hydroxide aqueous solution. The emulsion was then filtered through a 100-200 mesh filter to obtain a core-shell composite emulsion. The core-shell solid mass ratio in this emulsion was approximately 40:60, and the volume distribution particle size D of the core-shell latex particles was... 50 It is 1.2μm.

[0124] Preparation of binder system: The non-volatile content of the above core-shell structure composite emulsion and acrylic emulsion were determined according to ISO 3251:2019. After conversion, they were mixed at a ratio of 50:50 based on the total mass of film-forming resin solids to obtain the binder system, in which PHA solids accounted for 20 wt% based on the total mass of film-forming resin solids.

[0125] Ink formulation: The binder system consists of 50 parts of water-based dispersion, 25 parts of pigment paste, 3 parts of additives, and 22 parts of deionized water.

[0126] Preparation method: Place the prepared binder system in a dispersion vessel, add pigment paste, and stir evenly; add additives and deionized water, adjust the pH value and viscosity of the system, and filter to obtain the water-based ink composition.

[0127] Comparative example:

[0128] Comparative Example 1:

[0129] Formula by weight: 70 parts PHBV aqueous dispersion, 20 parts pigment paste, 5 parts ATBC, 2 parts additives, and 3 parts water.

[0130] Preparation method: Place the PHBV aqueous dispersion in a stirring container, add ATBC plasticizer, and stir evenly; add pigment paste and disperse evenly; add additives and water, adjust the system state, and filter to obtain water-based ink with single PHA film formation.

[0131] Comparative Example 2:

[0132] Formula by weight: 70 parts acrylic emulsion, 25 parts pigment paste, 3 parts additives, and 2 parts water.

[0133] Preparation method: Place acrylic emulsion in a stirring container; add pigment paste and stir to disperse; add additives and water, adjust the pH value to weakly alkaline, and filter to obtain water-based ink with single acrylic film formation.

[0134] Comparative Example 3:

[0135] Formula by weight: 60 parts waterborne polyurethane dispersion, 20 parts black pigment paste, 2 parts wax emulsion, 2 parts additives, and 16 parts water.

[0136] Preparation method: Aqueous polyurethane dispersion is used as the main resin; black pigment paste and wax emulsion are added and stirred evenly; additives and water are added, viscosity is adjusted, and the mixture is filtered to obtain a single polyurethane film-forming water-based ink.

[0137] Comparative Example 4:

[0138] Formulation by weight: PHBV aqueous dispersion and acrylic emulsion are physically mixed at a dry weight ratio of 30:70. The total solid content of the film-forming resin is consistent with that in Example 4. Pigment paste is 25 parts, additives are 3 parts, and water is added to make up to 100 parts.

[0139] Preparation method: PHBV aqueous dispersion and acrylic emulsion are physically blended in a certain proportion; pigment paste is added and stirred evenly; additives and water are added to adjust the pH and viscosity, and the mixture is filtered to obtain a physically blended water-based ink. This comparative example is used to compare the advantages of core-shell structure and the adverse effects of high PHA content.

[0140] Comparative Example 5:

[0141] Core-shell emulsion preparation: Referring to the polymerization process in Example 4, the ratio of monomer to seed was adjusted to control the core-shell solid mass ratio at 3:97, so that the core layer polymer accounted for only 3 wt% of the total film-forming resin solids, thus preparing a core-shell emulsion with low PHA content.

[0142] Ink formulation: 50 parts of the low PHA content core-shell emulsion, 25 parts of pigment paste, 3 parts of additives, and 22 parts of deionized water.

[0143] Preparation method: Same as in Example 4.

[0144] Comparative Example 6:

[0145] Core-shell emulsion preparation: using D 50 Using a 12.5 μm PHBV coarse particle suspension as a seed, emulsion polymerization was carried out according to the polymerization process in Example 4 to prepare a large-particle-size core-shell emulsion.

[0146] Ink formulation: 50 parts of the large-particle-size core-shell emulsion, 25 parts of pigment paste, 3 parts of additives, and 22 parts of deionized water.

[0147] Preparation method: Same as in Example 4.

[0148] Comparative Example 7:

[0149] Formula by weight: 50 parts PHBV aqueous dispersion, 10 parts acrylic emulsion, 10 parts pigment paste, 0.5 parts additives, and 29.5 parts water.

[0150] Preparation method: PHBV aqueous dispersion is mixed with acrylic emulsion; pigment paste is added and stirred to disperse; additives and water are added to adjust the system state, and the mixture is filtered to obtain water-based ink with high PHA content. The mass ratio of PHA to acrylic resin in this formulation is 79.2:20.8.

[0151] Comparative Example 8:

[0152] Formula by weight: 50 parts PHBV aqueous dispersion, 20 parts PBAT aqueous dispersion, 20 parts pigment paste, 5 parts ATBC, 2 parts additives, and 3 parts water.

[0153] Preparation method: Physically mix PHBV aqueous dispersion and PBAT aqueous dispersion; add ATBC plasticizer and stir evenly; add pigment paste and disperse evenly; add additives and water, and filter to obtain fully biodegradable polyester compound water-based ink.

[0154] Comparative Example 9:

[0155] Formula by weight: 0.175 parts PHBV aqueous dispersion, 66.5 parts acrylic emulsion, 20 parts pigment paste, 3 parts additives, and 10.325 parts water.

[0156] Preparation method: A very small amount of PHBV aqueous dispersion is added to acrylic emulsion; pigment paste is added and stirred evenly; additives and water are added, the pH value is adjusted, and the mixture is filtered to obtain a water-based ink with trace PHA content. In this formulation, PHA accounts for 0.2 wt% of the film-forming resin solids.

[0157] To clearly illustrate the key formulation parameters of each embodiment and comparative example, they are summarized in Table 3.

[0158] Table 3 Summary of Formulation Parameters for Examples and Comparative Examples:

[0159]

[0160] Note: The percentage of PHA in the film-forming resin (wt%) in Table 3 is calculated based on the dry weight of the film-forming resin solids (excluding colorants and additives); for core-shell structure systems, this percentage is the proportion of PHA solids in the core layer to the total mass of the core-shell emulsion film-forming resin solids; the percentage of PHA solids in the core layer to the total mass of the core-shell emulsion film-forming resin solids in Table 3 is as follows:50 "(μm)" represents the median diameter of the volume distribution of the binder system or its main latex particles. Comparative Example 8, containing two types of latex particles, lists the diameters of the PHBV and PBAT dispersions respectively. 50 .

[0161] Application example:

[0162] Application Example 1: Printability test of biaxially oriented polypropylene film (BOPP).

[0163] Experimental Description: This application example uses biaxially oriented polypropylene film treated with industrial-grade surface corona as the standard non-absorbent printing substrate. Before the experiment, the surface wetting tension was rigorously tested using a surface tension tester to ensure a value of not less than 40 mN / m to guarantee good ink wetting. The printing proofing process used a laboratory flexographic proofing machine with a ceramic anilox roller of 1200 lpi and a cell volume of 2.0 cm³ / m² to control the ink application. The printing speed was set to 0.8 m / s. Immediately after proofing, the sample was placed in a precision forced-air drying oven and dried at a constant temperature of 60℃ for 1 minute. The thickness was measured and screened at 5 points using a cross-sectional microscope, and the dry film thickness was controlled to be 2.5 μm. Subsequently, a full set of performance tests were conducted according to national standards. Adhesion was tested using the cross-cut adhesion test with standard pressure-sensitive tape; the anti-blocking grade was evaluated by pressing the tape together for 24 hours at 50℃ and a 5kg load using a dedicated anti-blocking tester; abrasion resistance was tested using a friction tester with 4-pound weights; surface gloss was measured using a 60-degree angle gloss meter; tactile feel was evaluated under blind testing conditions by a professional team; the surface water droplet contact angle was analyzed using a contact angle meter; and oxygen permeability was measured under standard temperature and humidity conditions using an oxygen permeability meter. This series of tests aims to comprehensively verify the film-forming quality and application potential of the binder system on typical plastic packaging substrates.

[0164] Table 4 shows the performance test results on the BOPP film substrate in Application Example 1:

[0165]

[0166] Analysis: Table 4 shows that on BOPP substrates, Examples 1-10, by introducing 0.5wt% to 25wt% PHA components, improved the anti-blocking performance from 2 points to 3-5 points compared to Comparative Example 2 with a pure acrylic system, and also significantly improved the water droplet contact angle, confirming the effectiveness of the PHA-enriched phase in reducing surface energy. At the lower limit of content, Example 8, with 0.5% PHA, showed better anti-blocking performance than Comparative Example 9, which only added 0.2% PHA; at the upper limit of content, Example 9, with 25% PHA, maintained a grade 0 adhesion, while Comparative Example 7, with a PHA content as high as 79.2%, saw its adhesion drop to grade 2 and its abrasion resistance deteriorate. Furthermore, the core-shell structure and the compound system showed a better overall balance, while the ultra-large particle size in Comparative Example 6 resulted in unsatisfactory adhesion and appearance. The results indicate that controlling the second film-forming resin to be a continuous phase is fundamental to ensuring mechanical properties.

[0167] Application Example 2: PLA film printing performance test.

[0168] Experimental Description: This application example aims to systematically evaluate the adhesion performance and interfacial compatibility of water-based inks on biodegradable PLA films to verify their applicability in the field of fully biodegradable packaging. A 25μm thick commercial PLA film was selected. Before the experiment, surface cleaning was performed to remove grease and dust, and its surface energy state was confirmed to meet printing requirements. Proofing and drying conditions were performed as in Application Example 1, but special attention was paid to strictly controlling the temperature to not exceed 60℃ during drying to prevent deformation or shrinkage of the heat-sensitive PLA substrate, which could affect the test results. Performance testing focused on three dimensions: adhesion, anti-blocking, and surface feel. Adhesion testing used the standard tape peeling method, paying particular attention to the interfacial bonding strength between the biopolyester substrate and the PHA-containing ink layer. Anti-blocking testing simulated the pressure state after roll-up, evaluating the anti-blocking ability under certain temperature and pressure conditions. The feel rating was conducted by several senior technicians using fingertip touch to quantitatively rate the smoothness and fineness of the ink layer from 1 to 5 points, without knowing the sample information. In addition, the water droplet contact angle was tested to characterize the surface's hydrophobic properties. The purpose of the above tests is to confirm whether the ink system can effectively overcome the technical problems of poor adhesion and slow drying that are common to traditional water-based inks on bio-based polyester films.

[0169] Table 5 shows the performance test results on the PLA film substrate in Application Example 2:

[0170]

[0171] Analysis: Table 5 shows that the PHA component exhibits significant interfacial affinity on PLA substrates. Comparative Example 2, with its pure acrylic system, showed an adhesion level of only 3 on PLA, while Examples 2, 4, 9, and 10, which incorporated PHA, all achieved an adhesion level of 0, indicating that PHA, as a bio-polyester, has good thermodynamic compatibility with PLA. The polyurethane and PHA system in Example 3 also performed better than the pure polyurethane system in Comparative Example 3. However, when the PHA content was too high and there was a lack of continuous phase support, as shown in Comparative Example 1, the cohesive force decreased, leading to an adhesion degradation to level 4. The data confirms that introducing an appropriate amount of PHA, while maintaining a continuous phase structure, is an effective way to improve the adhesion and anti-blocking properties of water-based inks on biodegradable polyester substrates.

[0172] Application Example 3: Paper repulping and deinking performance test.

[0173] Experimental Description: This application example, based on relevant international paper industry standards, simulates an industrial waste paper recycling process, focusing on the re-sizing properties and deinking efficiency of inks. First, the inks from each example and comparative example were printed on standard coated paper, and after thorough drying and aging, served as test samples. The samples were shredded and placed in a laboratory high-consistency hydraulic pulper, where dissociation was performed under alkaline conditions controlled at 40-50°C and a concentration of 10%-15%, with a dissociation time set at 20 minutes to ensure sufficient fiber dispersion. The pulp was then diluted and passed through a slotted screen with a specific aperture to remove large pieces of plastic and impurities. The flotation deinking stage was conducted in a laboratory flotation cell, with the addition of appropriate amounts of fatty acid trapping agents and foaming agents, followed by microbubbling for 10-15 minutes. The scum was collected, and the ink removal rate was calculated. Finally, the pulp was washed and formed into hand-made sheets on a laboratory press. The whiteness of the deinked pulp was measured using a whiteness meter under a D65 light source, and the residual ink dot area was calculated using an image analysis system. Simultaneously, fiber yield and coarse residue rate were calculated using mass balance. This experiment comprehensively evaluated the environmental friendliness and resource recycling value of the bio-based ink system in the papermaking circular economy through quantitative indicators, and verified whether it would generate adhesive obstacles.

[0174] Table 6. Results of re-sizing and deinking tests on coated paper printed materials:

[0175]

[0176] Analysis: Table 6 shows that within the PHA addition range of 0.5 wt% to 25 wt%, the fiber yield of Examples 1-10 remained around 90%, and the whiteness of the deinked pulp was comparable to that of Comparative Example 2, which used pure acrylic ink. This demonstrates that an appropriate amount of PHA does not become an adhesive impurity that hinders recycling. In contrast, Comparative Examples 1 and 7, with excessively high PHA content, showed a coarse residue rate exceeding 0.5%, and a significant decrease in the whiteness of the deinked pulp, indicating that excessive hydrophobic biopolyester is difficult to disperse effectively in hydraulic pulping. Furthermore, large-diameter PHA particles led to an increase in the residual ink dot area in Examples 6 and 6. The experimental results confirm that strictly controlling the content and particle size distribution of PHA is crucial to ensuring that bio-based inks possess good paper repulping and deinking performance.

[0177] Application Example 4: Performance test of 2.0μm dry film thickness.

[0178] Experimental Description: This application example aims to establish the intrinsic performance differences of various formulations under standard flexible packaging printing conditions by strictly controlling the thickness of a single dry film and eliminating the interference of ink layer thickness fluctuations on performance evaluation. The experiment used BOPP film with extremely high flatness. During the sampling process, a precision doctor blade or a high-line-count anilox roller of specific specifications was used for micro-coating. Five-point sampling measurements of the dried ink layer were performed using a cross-sectional microscope or a high-precision profilometer. Samples with a uniform and stable dry film thickness of 2.0 μm were rigorously selected for subsequent testing. The tests covered three key indicators: adhesion, anti-blocking, and abrasion resistance. The anti-blocking test not only examined the film at room temperature but also under strict testing conditions simulating high temperature and high pressure during summer transportation to verify the anti-blocking stability between film layers. The abrasion resistance test focused on examining the integrity and dust-removal ability of the extremely thin ink layer under mechanical friction. This standardized quantitative control method allows for a more sensitive capture of the subtle effects of different PHA contents and particle size distributions on the final film quality, providing precise data support for product formulation optimization and industrial quality control.

[0179] Table 7 shows the performance test results at a dry film thickness of 2.0 μm:

[0180]

[0181] Analysis: Table 7 shows that at a typical flexographic dry film thickness of 2.0 μm, all Examples 1-10 achieved adhesion grades of 0 to 1 and anti-blocking properties of 3 or higher, with Examples 2, 3, 4, and 10 achieving double 5-point levels. This indicates that at this thickness, the second film-forming resin can form a good continuous phase to encapsulate the PHA microregions, balancing film integrity and surface function. Conversely, Comparative Examples 2 and 9 only scored 2 points due to insufficient anti-blocking properties, failing to meet the winding requirements. Comparative Examples 1, 6, and 7 failed to meet adhesion or abrasion resistance standards due to film continuity disruption or excessively large particle size. This test further verifies that a PHA content of 0.5 wt% to 25 wt% and a particle size range of 0.2 μm to 2.0 μm are necessary conditions for achieving high-performance water-based inks at standard industrial thicknesses.

[0182] Application Example 5: Routine physical property testing.

[0183] Experimental Description: This application example, based on national and international standards, precisely determined the routine physicochemical properties of all prepared water-based ink samples. pH measurements were performed using a high-precision acidity meter calibrated at three points under constant temperature conditions of 25°C to ensure data accuracy and repeatability. For total solids content testing, a quantitative sample was placed in a pre-weighed weighing bottle, dried to constant weight in a 105°C forced-air drying oven, and the volatile content ratio was calculated using an analytical balance with a sensitivity of 0.1 mg. Fineness testing was conducted using a scraper fineness meter with a range of 0 to 25 μm or 0 to 50 μm, with two parallel measurements performed strictly according to the scraper operation specifications, and the critical scale value for particle appearance was read. Viscosity testing was performed in a constant temperature water bath at 25.0 ± 0.1°C, using a standard flow cup, with the flow time precisely recorded using a stopwatch, and necessary kinematic viscosity conversions performed. The collection of these basic physical property data not only verified the stability and reproducibility of the preparation process of each formulation, but also provided core parameter basis for subsequent rheological matching, drying speed prediction and storage stability assessment for printing, ensuring that the ink meets the factory standards for commercial products.

[0184] Table 8 Results of routine physical property tests:

[0185]

[0186] Analysis: Table 8 shows that the physical properties of all sample examples exhibit good process stability. The pH value of each formulation was controlled between 7.5 and 8.5, and the total solids content was maintained between 38% and 45%, meeting the basic requirements for ink application. Regarding fineness, except for Example 6 which intentionally used a larger particle size of approximately 8.5 μm, the fineness of the remaining examples was controlled below 5 μm, ensuring printing clarity. In contrast, Comparative Example 6, using coarse-grained PHA, achieved a fineness of 9.5 μm, approaching the industry standard upper limit, resulting in reduced gloss. Overall, the multi-component composite binder system of this invention, while introducing bio-based components, did not alter the basic rheological and processing characteristics of water-based inks, demonstrating good industrial adaptability.

[0187] Application Example 6: Screening for total fluoride content.

[0188] Experimental Description: This application strictly adheres to halogen determination standards, employing oxygen bomb combustion combined with ion chromatography for trace screening of total fluorine content in ink samples to verify the product's environmental compliance. First, the dried and cured ink coating was peeled off from the substrate and pulverized. 0.05 to 0.30 g of sample was accurately weighed and placed in a quartz combustion cup. 10 mL of a specific concentration of alkaline absorbent was added to the oxygen bomb, and high-purity oxygen was introduced to a pressure of 3.0 MPa before closed-loop ignition and combustion, converting organic fluorine into fluoride ions and completely dissolving them in the absorbent. After combustion and cooling, the inner wall of the bomb was washed multiple times with ultrapure water and the volume was adjusted. Subsequently, the processed solution was analyzed using a high-performance ion chromatograph equipped with an anion separation column and a conductivity detector, with a carbonate eluent system as the mobile phase. A standard curve was established using the external standard method, and blank experiments and spiked recovery rate verification were performed simultaneously during the testing process to ensure the reliability of the data below the detection limit of 5 mg / kg. This test aims to confirm that the developed bio-based ink formulation did not intentionally contain any fluorinated surfactants or additives, and fully complies with increasingly stringent global regulations on fluorine-free food contact materials.

[0189] Table 9. Results of Total Fluorine Content Test:

[0190]

[0191] Analysis: Table 9 shows that the total fluorine content of all examples and comparative samples was below the instrument detection limit of 5 mg / kg, and was therefore determined to be undetectable. This data objectively confirms that the formulation system of this invention did not intentionally add organic fluorides, meeting the requirements of fluorine-free technology. Experimental results show that the excellent anti-blocking and hydrophobic properties exhibited by each example are entirely due to the crystallization characteristics of PHA biopolyester and the micro-phase separation structure constructed in the binder, rather than relying on fluorinated surfactants or additives. This verifies the compliance and reliability of this technical solution in meeting stringent environmental regulations and food contact material safety standards.

[0192] Application Example 7: Characterization of dry film microstructure and discrete phase domain size.

[0193] Experimental Description: This application example aims to directly observe and quantitatively analyze the microscopic two-phase structure of water-based ink after drying and film formation using high-resolution microscopic imaging technology, in order to verify the microscopic discrete phase domain size characteristics of the water-based ink composition of the present invention.

[0194] Sample preparation: The ink samples of each embodiment and comparative example were coated on a surface-treated PET film and dried in a 60°C forced-air drying oven for 24 hours to ensure complete solvent evaporation. The dry film thickness was controlled at 2.0±0.2μm.

[0195] Freeze-fracture: The sample containing the dry film is immersed in liquid nitrogen for 5 minutes and subjected to rapid brittle fracture to expose the undeformed coating cross section.

[0196] Morphology observation: The brittle fracture section was sputter-coated with gold (approximately 5 nm thick), and the cross-sectional morphology was observed using field emission scanning electron microscopy (FE-SEM) at an accelerating voltage of 3.0 kV. For systems with small phase differences, osmium tetroxide (OsO4) vapor staining was used to enhance the contrast between the PHA phase and the second film-forming resin phase.

[0197] Data analysis: SEM cross-sectional images were processed using ImageJ image analysis software. PHA-enriched phases (typically appearing as spherical or ellipsoidal particles) were selected as target regions for threshold segmentation and edge recognition. At least three fields of view were randomly selected for each sample, and no fewer than 100 discrete phase domain particles were counted. Their equivalent circle diameters were calculated as feature sizes, and the average value and distribution range (D) were obtained. 10 -D 90 ).

[0198] Table 10 Statistical results of discrete phase domain dimensions of dry film cross-section:

[0199]

[0200] Analysis: The microscopic statistical data in Table 10 provides direct evidence for the "average characteristic size of the discrete phase domain" in this invention. Size compliance verification: After drying and film formation, the PHA-enriched phases of all examples (1-10) maintained a stable discrete state, with the average characteristic size strictly falling within the protection range of 0.2 μm to 2.0 μm. Among them, the core-shell structure system (such as Examples 4 and 5) showed a larger size distribution range (D) of the discrete phase domain compared to the physically blended system (such as Examples 1 and 2). 10 -D 90 The narrower core-shell structure indicates that the core-shell structure can more effectively suppress micro-region aggregation and maintain the original morphology of particles during film formation.

[0201] Correlation between morphology and performance: Combining the performance data of Application Example 1 and Application Example 4, it can be seen that when the discrete phase domain size is controlled in the range of 0.2-0.4 μm (as in Examples 1-5), the ink exhibits high gloss (>30 GU) and excellent adhesion; when the size is close to the upper limit of 2.0 μm (as in Example 6), the coating exhibits a matte effect (gloss 1.5 GU), while having excellent anti-blocking properties, but the adhesion decreases slightly.

[0202] Comparative Example Analysis: Comparative Example 6 used large-diameter seeds, resulting in an average size of 12.60 μm for the discrete phase domain after film formation, far exceeding the upper limit of 2.0 μm. This directly explains its poor adhesion (level 2) and low abrasion resistance (2 points) in Application Example 4—excessively large particles disrupt the continuity and integrity of the paint film. Comparative Examples 1 and 7, due to their excessively high PHA content, could not form an "island structure" with the second resin as the continuous phase and PHA as the dispersed phase, and therefore this size characteristic limitation was not applicable.

[0203] Application Example 8: Industrial composting performance test.

[0204] Experimental Description: This application example aims to verify the biodegradation and disintegration performance of the water-based ink composition under industrial composting conditions. The experiment was conducted according to EN 13432:2000, including chemical characterization, biodegradability, disintegration capacity, and ecotoxicity testing. The water-based inks of Examples 1-10 and Comparative Examples 1-9 were uniformly coated onto certified compostable PLA films, dried, and used to prepare test samples with a dry film thickness controlled at 2.0 μm. The samples were placed in a composting reactor at a controlled temperature of 58±2℃ and humidity of 50-55%, inoculated with mature compost as inoculum. The samples were periodically turned and aerated, and carbon dioxide release was continuously monitored using an infrared gas analyzer to calculate the biodegradation rate (percentage relative to reference cellulose). Disintegration tests were conducted at week 12, and residues larger than 2 mm were screened and weighed; the biodegradation test concluded at day 180. The composted material was collected for plant (watercress and summer barley) germination rate and biomass testing to assess ecotoxicity. Comparative Example 2 (pure acrylic acid) and Comparative Example 9 (trace amount of PHA) were used as negative controls because they were expected to be difficult to degrade, while Comparative Example 1 (pure PHA) and Comparative Example 8 (fully bio-based) were used as positive controls.

[0205] Table 11 Performance test results under industrial composting conditions:

[0206]

[0207] Analysis: The industrial composting test results in Table 11 show that Examples 1-10 of this invention all meet the requirements of EN 13432. All examples exhibited a disintegration rate exceeding 90% (virtually close to 100%) within 12 weeks, and an absolute biodegradation rate greater than 90% within 180 days. This is because the PHA dispersed phase was rapidly eroded by thermophilic microorganisms under high-temperature composting conditions (58°C), forming numerous microporous defects within the ink layer, promoting the physical disintegration of the continuous phase resin and subsequent mineralization. In contrast, the pure acrylic acid system (Comparative Example 2) and the trace PHA system (Comparative Example 9) lacked sufficient biodegradation sites, forming a complete inert plastic film, resulting in disintegration and biodegradation rates far below the standard requirements. Notably, Example 7 (containing starch derivatives) exhibited the highest biodegradation rate (98.2%), demonstrating the synergistic degradation effect of the natural polymer and PHA. Furthermore, phytotoxicity tests showed that the germination rate of all examples was above 90%, proving that the degradation products were non-ecotoxic.

[0208] Application Example 9: Home composting performance test.

[0209] Experimental Description: This application example aims to evaluate the degradation performance of water-based ink compositions in a home composting environment (low temperature, uncontrolled). The experiment was conducted according to AS 5810-2010 standard. Sample preparation was the same as in Application Example 8. Samples were placed in a simulated home composting bin at a temperature of 25±5℃, mixed with garden waste and kitchen waste. Due to the lower temperature in home composting, microbial activity is weaker than in industrial composting; therefore, the focus was on examining the sample's disintegration capacity and final biodegradation rate at room temperature. The test period was extended to 360 days. Samples were taken periodically to observe changes in the physical morphology of the samples, and the mass of the residue and biodegradation rate were measured at the end of the test.

[0210] Table 12 Performance test results under home composting conditions:

[0211]

[0212] Analysis: Table 12 shows that, even in the more temperate home composting environment, Examples 1-10 of this invention still exhibit good degradation potential, meeting the AS 5810 standard requirements (biodegradability > 90%). Among them, Examples 4 and 5, with their core-shell structures, showed superior disintegration rates compared to the physically mixed system (Example 1). This is presumably because the interfacial effect of the core-shell particles introduced more micro-phase interfaces during the ink drying process, facilitating the penetration of moisture and room-temperature microorganisms. For Example 8 (0.5 wt% PHA), with its low PHA content, although it barely passed the 90% threshold, its degradation rate was significantly slower than that of Example 9 (25% PHA), further confirming the positive contribution of PHA content to degradation performance. Comparative Example 5, due to its excessively low and unevenly dispersed PHA content, failed to meet the 90% biodegradability requirement under home composting conditions, indicating that a sufficient amount of bio-based components is needed to drive the degradation process in the absence of high-temperature assistance.

[0213] Experimental Results and Analysis:

[0214] Based on the performance test data of Examples 1-10 and Comparative Examples 1-9 at BOPP film, PLA film, paper re-pulping and deinking, and a dry film thickness of 2.0 μm, the technical effects and structure-property relationship of the PHA-containing multi-component water-based ink binder system proposed in this invention are analyzed as follows:

[0215] Analysis of the influence trend of PHA content on performance: By systematically comparing examples and comparative examples with different PHA contents, this experiment reveals the significant influence of the content of PHA as a dispersed enriched phase or core layer component in the film-forming resin solid on ink performance.

[0216] (1) Improvement range of anti-blocking properties and tactile feel: Data shows that as the PHA content increased from 0.5 wt% (Example 8) to 25.0 wt% (Examples 4, 6, and 9), the anti-blocking score of the printed layer improved from 3 to 5, and the tactile feel score improved from 4 to 5. In particular, when the PHA content exceeded 5 wt%, the anti-blocking performance generally reached above 4 (excellent). This indicates that the crystallization characteristics and microphase separation structure of PHA can effectively reduce the viscosity coefficient of the film surface.

[0217] (2) Definition of the critical threshold: When the PHA content is below 0.5 wt% (e.g., 0.2 wt% in Comparative Example 9), its anti-blocking properties (2 points) and tactile feel (2 points) are almost identical to those of the pure acrylic system (Comparative Example 2), indicating that trace amounts of PHA are insufficient to construct effective roughness or low surface energy micro-regions on the film surface. When the PHA content exceeds the upper limit of 25 wt% (e.g., 30 wt% in Comparative Example 4 and 79.2 wt% in Comparative Example 7), although the anti-blocking properties remain excellent (5 points), the adhesion deteriorates significantly from level 0 to level 1-2, and the abrasion resistance decreases from 4-5 points to 2-3 points. This is because excessive PHA disrupts the continuous phase structure formed by the second film-forming resin (e.g., acrylic acid or polyurethane), leading to a decrease in the cohesive force of the ink layer and the failure of the interfacial bonding force. This confirms that 0.5 wt%-25 wt% is the necessary range for achieving a balance between anti-blocking properties and mechanical properties, perfectly matching the structural design theory of this invention regarding "the second film-forming resin forming a continuous phase, and PHA forming a dispersed and enriched phase".

[0218] Analysis of the influence of dispersed phase particle size and dry film microstructure on film quality: Regarding the influence of dispersed phase particle size on performance, the SEM cross-sectional observation results of Application Example 7 and the performance data of Application Examples 1 and 4 reveal a strong correlation between microstructure and macroscopic performance.

[0219] (1) Correspondence between liquid particle size and dry film phase domain: Compare the liquid D in Table 3 50 The data, compared with the dry film discrete phase domain size data in Table 10, show that the core-shell structure system (Examples 4 and 5) can maintain the original particle size to a high extent after film formation without significant fusion; while the dry film phase domain size of the physical blend system (Examples 1 and 2) is slightly larger than the liquid particle size, indicating that there is slight particle accumulation during the drying process, but the average size is still strictly controlled within the range of 0.2-2.0 μm.

[0220] (2) Inverse relationship between size and gloss: Under the same composition, the smaller the size of the discrete phase domain, the higher the gloss of the coating. The systems of Examples 1, 4, 5 and 9, with dry film phase domain sizes of 0.2-0.36 μm, all have glosses above 30 degrees; while Example 6, with a dry film phase domain size close to the upper limit (1.95 μm), has a gloss level of 1.5 degrees, exhibiting a matting effect.

[0221] (3) Necessity of Size Limitation: This invention limits the average characteristic size of the discrete phase domain to 0.2 μm-2.0 μm. Data shows that when the size far exceeds this range (e.g., in Comparative Example 6, the dry film phase domain size reaches 12.60 μm), the huge PHA particles severely disrupt the film continuity at a dry film thickness of 2.0 μm, resulting in an adhesion level of 2 and an abrasion resistance score of only 2. This strongly confirms the critical significance of controlling the size of the dispersed and enriched phase below 2.0 μm.

[0222] Comparative analysis of core-shell structure and physical blending processes: A comparison of Examples 4 and 5 (core-shell structure) with Examples 1 and 9 (physical blending) shows that, at similar PHA contents, the core-shell structure system generally exhibits superior overall performance stability. For example, Example 4 (25% PHA, core-shell) showed an adhesion grade of 0 and an abrasion resistance score of 5 on BOPP; while physical blending at the same content also met the standards, under extreme conditions (such as high-shear printing), the compatibility protection provided by the core-shell structure better prevented the shedding of PHA particles, and the storage stability of the core-shell emulsion was theoretically superior to that of a simple physical mixture.

[0223] Structure-activity relationship analysis of compost degradation performance: By combining the data from Example 8 and Example 9, the key influence of the microstructure of the binder system on biodegradability was revealed.

[0224] (1) Driving effect of PHA content: In both industrial and household composting modes, the biodegradation rate increases with the increase of PHA content. Data shows that when the PHA content is in the range of 0.5-25wt%, it can not only meet the physical requirements for anti-blocking, but also provide sufficient biodegradable active sites to ensure the compliance of the ink in the environmentally friendly disposal terminal.

[0225] (2) Synergistic effect of phase structure: Compared with simple physical blending, the core-shell structure (as in Example 4) exhibits more stable degradation consistency in home composting. This is because the core-shell particles construct uniformly distributed "biodegradable islands," avoiding disintegration residues caused by local PHA depletion.

[0226] Substrate adaptability and biodegradability / recyclability analysis:

[0227] (1) Substrate versatility: The system of this invention not only performs well on non-polar substrates (BOPP), but also exhibits unique affinity advantages on bio-based polar substrates (PLA). The adhesion of the system in the examples to PLA is generally better than that of the pure acrylic system (Comparative Example 2), which is attributed to the thermodynamic compatibility of PHA and PLA, both belonging to the polyester family.

[0228] (2) Re-pulping and deinking performance: Application Example 3 confirmed that when the PHA content is controlled within 25 wt% (Examples 1-10), the ink can form appropriately sized fragments and be effectively removed during the paper recycling process, with high fiber yield (approximately 90%) and deinked pulp brightness (approximately 85%). Conversely, pure PHA or high PHA content systems (Comparative Examples 1 and 7) are prone to forming adhesives during pulping due to their excessive hydrophobicity and thermoplasticity, leading to an increase in coarse residue and a decrease in pulp brightness.

[0229] In summary, this invention successfully constructed a microstructure with the second resin as the continuous phase and PHA as the dispersed and enriched phase by precisely controlling the mass ratio of PHA to the second film-forming resin (0.5-25:75-99.5) and the particle size of the dispersed phase. The microscopic characterization in Application Example 7 directly confirms that this two-phase structure maintains the discrete phase domain size within the range of 0.2-2.0 μm after drying and film formation. This specific structure, at an extremely thin dry film thickness, utilizes the film-forming continuity of the second resin to ensure adhesion and abrasion resistance, while leveraging the crystallization characteristics of the PHA microregions to impart surface anti-adhesion and a bio-based feel. Simultaneously, it also achieves excellent paper recycling performance, solving the problem of balancing performance and environmental friendliness in existing bio-based water-based inks.

[0230] Those skilled in the art should understand that the above embodiments are merely exemplary and are not intended to limit the scope of the present invention. Any modifications, equivalent substitutions, improvements, etc., made to the technical solutions of the present invention within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A polyhydroxyalkanoate-containing multi-component aqueous ink vehicle system, characterized in that, The binder system is an aqueous dispersion comprising an aqueous dispersion medium and dispersed therein film-forming resin solids, the film-forming resin solids comprising at least a polyhydroxyaliphatic ester component and a second film-forming resin component, wherein: The solid content of the polyhydroxyaliphatic ester component is a polyhydroxyaliphatic ester or a copolymer thereof; The solid content of the second film-forming resin component is a second film-forming resin; The polyhydroxyaliphatic ester component and the second film-forming resin component are dispersed in the aqueous dispersion medium by one or a combination of both of the following: 1) the polyhydroxyaliphatic ester component is present as an aqueous dispersion of polyhydroxyaliphatic ester and the second film-forming resin component is present as an aqueous dispersion or aqueous solution of a second film-forming resin; 2) the polyhydroxyaliphatic ester component and the second film-forming resin component together form the latex particles of a core-shell structured complex emulsion, the latex particles comprising a core layer comprising polyhydroxyaliphatic ester and a shell polymer comprising the second film-forming resin coating the core layer; The polyhydroxyaliphatic ester component comprises 0.5 to 25 wt% of the total mass of film-forming resin solids and the second film-forming resin component comprises 75 to 99.5 wt% of the total mass of film-forming resin solids, and the second film-forming resin forms a continuous phase and the polyhydroxyaliphatic ester forms a dispersed rich phase after drying and film formation; The binder system has a volume distribution particle size D50 of 0.2 μm to 2.0 μm at 25°C as measured by dynamic light scattering or laser diffraction; The second film-forming resin is selected from at least one of the following: an aqueous acrylic resin emulsion or aqueous solution, an aqueous polyurethane dispersion, an aqueous vinyl resin emulsion, an aqueous biodegradable polyester dispersion, an aqueous dispersion or aqueous solution of a natural polymer derivative, and an aqueous dispersion or aqueous solution of a natural resin and its modified product.

2. The polyhydroxyalkanoate-containing multiple composite aqueous ink binder system according to claim 1, characterized in that, The polyhydroxyaliphatic ester is selected from a short chain polyhydroxyaliphatic ester, a medium chain polyhydroxyaliphatic ester, or a copolymer between monomers forming short chain and medium chain polyhydroxyaliphatic esters; The short chain polyhydroxyaliphatic ester is selected from one or more of the following short chain polyhydroxyaliphatic esters: poly-3-hydroxybutyrate, poly-3-hydroxybutyrate-co-3-hydroxyvalerate, poly-3-hydroxybutyrate-co-4-hydroxybutyrate; The medium chain polyhydroxyaliphatic ester is selected from a homopolymer or copolymer of 3-hydroxyaliphatic acid monomers having a carbon number of 6 to 16, the 3-hydroxyaliphatic acid monomers being selected from one or more of the following: 3-hydroxyhexanoic acid, 3-hydroxyheptanoic acid, 3-hydroxyoctanoic acid, 3-hydroxynonanoic acid, 3-hydroxydecanoic acid, 3-hydroxyundecanoic acid, 3-hydroxydodecanoic acid, 3-hydroxytetradecanoic acid, and 3-hydroxyhexadecanoic acid.

3. The polyhydroxyalkanoate-containing multiple composite aqueous ink binder system of claim 1, wherein, The second film-forming resin is a polymer polymerized from one or more of the following monomers and mixtures thereof: acrylic acid, methacrylic acid, and acrylic and methacrylic ester monomers esterified from C1-C8 linear or branched alcohols, including methyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, butyl methacrylate; Styrene and substituted styrene monomers, including styrene, alpha-methyl styrene, vinyl toluene; ethylene and vinyl ester monomers, including ethylene, vinyl acetate, and auxiliary monomers used in copolymerization with other vinyl monomers to form ethylene-vinyl acetate copolymers, polyvinyl acetate, and other vinyl copolymers; Polyurethanes resulting from the polycondensation of diisocyanate monomers selected from one or more of isophorone diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, and diphenylmethane diisocyanate, with polyol monomers selected from one or more of polyester polyols, polyether polyols, and polycarbonate polyols; Biodegradable polyesters, including PLA and copolymers thereof resulting from the polycondensation or ring-opening polymerization of lactic acid and / or glycolic acid; and / or poly(butylene adipate-co-terephthalate), poly(butylene succinate), and copolymers thereof resulting from the polycondensation of one or more of succinic acid, adipic acid, terephthalic acid, with one or more of ethylene glycol, propylene glycol, butylene glycol; Natural polymer derivatives and natural resin modifications, including starch composed of glucose repeat units or etherized or esterified derivatives thereof, cellulose composed of beta-glucose repeat units and carboxymethyl or hydroxyethyl derivatives thereof, rosin resins based on rosin acids and adducts thereof and salts or esters thereof, and polymers modified by crosslinking or grafting based on soy protein or other plant proteins; the second film-forming resin being used to prepare an aqueous ink vehicle to provide a continuous film-forming phase at a dry film thickness of 0.5-5 μm.

4. The polyhydroxyalkanoate-containing multiple composite aqueous ink binder system of claim 1, wherein, The vehicle system further comprises an interfacial compatibilizer or reactive coupling agent, the interfacial compatibilizer or reactive coupling agent being added in an amount of 0.05-10 wt% based on the total mass of film-forming resin solids of the polyhydroxyalkanoate component and the second film-forming resin component, the interfacial compatibilizer or reactive coupling agent being selected from at least one of: a block or graft copolymer containing hydrophilic and hydrophobic segments; a polymeric dispersant; a reactive coupling component containing an epoxy, carboxyl, hydroxyl, isocyanate, carbodiimide, or aziridine group.

5. The polyhydroxyalkanoate-containing multiple composite aqueous ink binder system of claim 1, wherein, The vehicle system satisfies one or more of the following physical property parameters or structural features: a pH of 7.0-10.0 at 25°C; a total solids content of 15-60 wt%; and, upon drying to form a film, the polyhydroxyalkanoate-rich phase forms discrete phase domains having an average characteristic size of 0.2-2.0 μm.

6. The polyhydroxyalkanoate-containing multiple composite aqueous ink binder system of claim 1, wherein, The adhesive system comprises a core-shell structure composite emulsion, wherein: the latex particles of the core-shell structure composite emulsion comprise a core layer containing polyhydroxyaliphatic ester and a shell layer polymer coated outside, the polymer solid of the core layer comprises polyhydroxyaliphatic ester or a copolymer thereof, and the shell layer polymer solid comprises at least one of an acrylic resin, a polyurethane resin, a vinyl resin or a biodegradable polyester resin; the latex particles of the core-shell structure composite emulsion satisfy the volume distribution particle size D 50 is 0.2 μm-2.0 μm, and the core layer accounts for 5-40 wt% and the shell layer accounts for 60-95 wt% based on the total mass of the core layer and the shell layer polymer solid.

7. The polyhydroxyalkanoate-containing multiple composite aqueous ink binder system of claim 1, wherein, The shell layer polymer is a polymer polymerized from one or more of the following monomers and mixtures thereof, and the glass transition temperature Tg of the shell layer polymer is -40-120℃: a copolymer formed from acrylic acid, methacrylic acid and C1-C8 alkyl ester monomers thereof, or a copolymer formed from acrylic acid, methacrylic acid and C1-C8 alkyl ester monomers thereof and styrene monomers; an aliphatic or aromatic polyurethane obtained by polycondensation of isophorone diisocyanate, hexamethylene diisocyanate, toluene diisocyanate or diphenylmethane diisocyanate with polyester polyol, polyether polyol or polycarbonate polyol; an ethylene-vinyl acetate copolymer, polyvinyl acetate or other vinyl copolymer formed from ethylene and vinyl acetate and other vinyl monomers copolymerized therewith; a polylactic acid, polybutylene adipate terephthalate, polybutylene succinate or copolymer thereof obtained by polycondensation of one or more of lactic acid, glycolic acid, succinic acid, adipic acid, terephthalic acid with one or more of ethylene glycol, propylene glycol, butanediol; optionally, the shell layer polymer copolymerizes a monomer containing carboxyl, hydroxyl, epoxy, carbamate or carbodiimide groups.

8. The polyhydroxyalkanoate-containing multiple composite aqueous ink binder system of claim 1, wherein, The core-shell structure composite emulsion provides 10-60wt% of the total mass of the film-forming resin solids in the binder system, and the second film-forming resin solids provided by the second film-forming resin aqueous dispersion or aqueous solution additionally added in the binder system account for 40-90wt%.

9. An aqueous ink composition characterized in that, The water-based ink composition comprises the polyhydroxy aliphatic ester-containing multi-component water-based ink binder system, a colorant, and a water-based medium; the water-based ink composition comprises, by weight, 30-70 parts of the binder system in the form of an aqueous dispersion, 8-30 parts of the colorant or a colorant-containing color paste, 0.5-8 parts of an additive, and the balance of the water-based medium; wherein the total fluorine content, measured as dry solids and according to EN 14582:2016 closed system oxygen bomb combustion-ion chromatography, is less than 5mg / kg. The additive at least comprises one or more of wetting dispersants, defoamers, and leveling agents; optionally, the water-based ink composition further comprises a bio-based plasticizer selected from one or more of acetyl tributyl citrate, triethyl citrate, tributyl citrate, tri(2-ethylhexyl) citrate, epoxidized vegetable oil, polyester plasticizer, or glycerol ester.

10. The aqueous ink composition according to claim 9, characterized in that, The water-based ink composition satisfies at least one of the following: a total solid content of 30-60wt%; a fineness of ≤10μm.

11. The aqueous ink composition according to claim 9, characterized in that, The water-based ink composition satisfies the biodegradation and disintegration requirements of the industrial composting standard EN 13432 or the home composting standard AS 5810, and the biodegradation rate is greater than 90% within 180 days under controlled composting conditions.

12. The aqueous ink composition according to claim 9, characterized in that, The method comprises the following steps:

13. A method of producing the aqueous ink composition according to claim 9, characterized by, The shell layer polymer is a polymer polymerized from one or more of the following monomers and mixtures thereof, and the glass transition temperature Tg of the shell layer polymer is -40-120℃: a copolymer formed from acrylic acid, methacrylic acid and C1-C8 alkyl ester monomers thereof, or a copolymer formed from acrylic acid, methacrylic acid and C1-C8 alkyl ester monomers thereof and styrene monomers; an aliphatic or aromatic polyurethane obtained by polycondensation of isophorone diisocyanate, hexamethylene diisocyanate, toluene diisocyanate or diphenylmethane diisocyanate with polyester polyol, polyether polyol or polycarbonate polyol; an ethylene-vinyl acetate copolymer, polyvinyl acetate or other vinyl copolymer formed from ethylene and vinyl acetate and other vinyl monomers copolymerized therewith; a polylactic acid, polybutylene adipate terephthalate, polybutylene succinate or copolymer thereof obtained by polycondensation of one or more of lactic acid, glycolic acid, succinic acid, adipic acid, terephthalic acid with one or more of ethylene glycol, propylene glycol, butanediol; optionally, the shell layer polymer copolymerizes a monomer containing carboxyl, hydroxyl, epoxy, carbamate or carbodiimide groups. The core-shell structure composite emulsion provides 10-60wt% of the total mass of the film-forming resin solids in the binder system, and the second film-forming resin solids provided by the second film-forming resin aqueous dispersion or aqueous solution additionally added in the binder system account for 40-90wt%. The water-based ink composition comprises the polyhydroxy aliphatic ester-containing multi-component water-based ink binder system, a colorant, and a water-based medium; the water-based ink composition comprises, by weight, 30-70 parts of the binder system in the form of an aqueous dispersion, 8-30 parts of the colorant or a colorant-containing color paste, 0.5-8 parts of an additive, and the balance of the water-based medium; wherein the total fluorine content, measured as dry solids and according to EN 14582:2016 closed system oxygen bomb combustion-ion chromatography, is less than 5mg / kg. The additive at least comprises one or more of wetting dispersants, defoamers, and leveling agents; optionally, the water-based ink composition further comprises a bio-based plasticizer selected from one or more of acetyl tributyl citrate, triethyl citrate, tributyl citrate, tri(2-ethylhexyl) citrate, epoxidized vegetable oil, polyester plasticizer, or glycerol ester. The water-based ink composition satisfies at least one of the following: a total solid content of 30-60wt%; a fineness of ≤10μm. The water-based ink composition satisfies the biodegradation and disintegration requirements of the industrial composting standard EN 13432 or the home composting standard AS 5810, and the biodegradation rate is greater than 90% within 180 days under controlled composting conditions. The method comprises the following steps: Step 1. Preparing a composite binder system comprising polyhydroxyal-kanoate and second film-forming resin under the condition of full aqueous phase, by one or a combination of the following ways: physically mixing polyhydroxyalkanoate aqueous dispersion with pH adjusted to 7.5-8.5 and second film-forming resin aqueous dispersion or aqueous solution in aqueous medium in proportion; or in-situ emulsion polymerization of monomers of second film-forming resin in the presence of polyhydroxyalkanoate aqueous dispersion, the monomers being added after pre-emulsified in water to form second film-forming resin aqueous dispersion; when interfacial compatibilizer or reactive coupling agent is present, it is added in the preparation of polyhydroxyalkanoate aqueous dispersion or second film-forming resin aqueous dispersion, in the process of physical mixing or in-situ emulsion polymerization, or after the preparation of the composite binder system is completed, to obtain the composite binder system; Step 2. Grinding or high-speed dispersing colorant with part of aqueous medium in the presence of wetting dispersant until the target fineness and particle size distribution are reached to obtain color paste; Step 3. Adding the color paste into the composite binder system obtained in Step 1 under stirring, sequentially adding other additives and the remaining aqueous medium, adjusting the viscosity and pH, and filtering to obtain aqueous ink composition.

14. The method of claim 13, wherein, The way of in-situ emulsion polymerization in Step 1 includes: emulsion polymerization of shell monomers in the presence of polyhydroxyalkanoate latex seed with water as continuous phase, the shell monomers being added after aqueous emulsification under the condition of controlling the dropping rate and temperature to obtain core-shell structure composite emulsion.

15. Use of the aqueous ink composition according to claim 9, characterized in that, The aqueous ink composition is used for flexographic printing, gravure printing or screen printing, in the form of top printing or inside printing, to form ink graphic layer on the surface or inner layer of the printing substrate, the dry film thickness of the ink graphic layer being 0.5-5 μm; The printing substrate includes paper, paperboard, polyester film including polyethylene terephthalate film and biodegradable polyester film, or surface-treated polyolefin film.

16. A printed layer, characterized in that The printing layer formed by flexographic printing, gravure printing or screen printing of the aqueous ink composition of claim 9 and drying and curing has a dry film thickness of 0.5-5 μm; the printing layer comprises continuous phase formed by second film-forming resin and polyhydroxyalkanoate-rich phase particles dispersed in the continuous phase.

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