PHA dispersion coating composition and coated fiber substrate

Abstract

The present invention relates to a dispersion coating composition for coating a fibrous substrate, wherein the dispersion coating composition comprises, in a liquid medium, 50 to 99% by weight of PHA (polyhydroxyalkanoate) particles based on the total solids content of the dispersion coating composition, and 1 to 50% by weight of a low molecular weight polyol dispersant based on the total solids content of the dispersion coating composition, and the total solids content of the dispersion coating composition is in the range of 20 to 80% by weight. The present invention further relates to a fibrous substrate coated with such a dispersion coating composition, and a packaging container containing such a dispersion coated fibrous substrate.

Description

[Technical Field]

[0001] This disclosure relates to a method for preparing coated fiber substrates, specifically polyhydroxyalkanoate (PHA) coated paper or cardboard, for use as packaging materials. [Background technology]

[0002] Plastic coatings of fibrous substrates such as paper and cardboard are often used to combine the mechanical properties of the fibrous substrate with the barrier and sealing properties of the plastic film. Even paper or cardboard with relatively small amounts of suitable plastic material can provide the properties necessary to make the paper or cardboard suitable for many demanding applications, such as liquid or food packaging.

[0003] In addition to the liquid barrier inside the packaging, fiber-based packaging products, such as cups or trays, especially those intended for packaging cold products, typically require a condensation layer on the outside of the packaging. This condensation layer prevents condensation from softening the bulky fibrous substrate. The packaging product also typically includes at least one heat-sealable liquid barrier on the inside.

[0004] In liquid or food packaging paperboard, extruded polyolefin coatings are frequently used as liquid barrier layers, heat seal layers, and adhesives. However, recycling such polymer-coated paperboard is not easy because separating the polymer from the fibers is difficult.

[0005] Prior art has attempted to replace extruded polyolefin coatings with more environmentally friendly and / or more recyclable solutions, but so far there have been no actual successes. In many cases, some, if not all, of the properties of extruded polyolefin coatings are achieved by the alternative solutions.

[0006] Dispersion barrier coatings for paper and cardboard are an interesting alternative to extrusion coatings for improving the repulpability and recyclability of barrier-coated fibrous substrates. Dispersion coatings are particularly useful because they can be carried out online in paper machines or cardboard manufacturers. However, many dispersions or emulsions, such as styrene / acrylate emulsions or styrene / butadiene emulsions, are not biodegradable or compostable.

[0007] On the other hand, polyhydroxyalkanoate (PHA)-based dispersion coating barriers are compostable and biodegradable. The challenge with PHA dispersions is finding the right composition to enable good runability in coating machines, good coating holdout, and good barrier performance. Coating holdout and subsequent barrier performance depend heavily on the roughness of the substrate and the amount of coating, but too much coating negatively impacts recyclability, drying efficiency, and cost. PHA dispersions are usually stabilized by surfactants and / or surfactant polymers, but migration of dispersants and increased foaming tendencies can lead to non-uniformity of barrier performance. Foaming tendencies can cause further problems during recycling, repulping, or defibration of coated webs.

[0008] Many of the aforementioned problems can be avoided by applying PHA using melt extrusion coating. However, unfortunately, extrusion coating of PHA cannot be performed online on a full-scale paper machine or paperboard manufacturer. Furthermore, extrusion coating usually requires a relatively large amount of coating and tends to have inferior adhesion compared to dispersion-coated products. In addition, extruded-coated products are more difficult to repulp than dispersion-coated products.

[0009] Therefore, there is still a need for an improved solution to replace conventional plastic coatings, particularly polyolefin coatings, in paper and cardboard-based packaging materials while maintaining acceptable liquid barrier properties. At the same time, there is a need for a liquid barrier layer for fibrous substrates such as paper or cardboard that facilitates the repulping and recycling of used packaging materials compared to packaging laminates using conventional plastic films. SUMMARY OF THE INVENTION

[0010] An object of the present disclosure is to provide an alternative to plastic films commonly used as barrier layers for providing liquid barrier properties in paper or cardboard-based packaging materials such as liquid or food packaging boards. <L

[0011] A further object of the present disclosure is to provide a liquid barrier layer for paper or cardboard-based packaging materials such as liquid or food packaging cardboard, based on renewable raw materials.

[0012] A further object of the present disclosure is to provide a liquid barrier layer for paper or cardboard-based packaging materials such as liquid or food packaging cardboard that facilitates the repulping of the packaging materials compared to packaging laminates using conventional plastic films.

[0013] A further object of the present disclosure is to provide an improved PHA coating dispersion that overcomes or ameliorates at least some of the problems associated with conventional PHA coating dispersions.

[0014] The above objects, as well as other objects realized by those skilled in the art in light of the present disclosure, are achieved by various aspects of the present disclosure.

[0015] The present invention is based on the understanding that by using a relatively large amount of a low molecular weight polyol as a dispersant for PHA particles, it is possible to overcome problems related to the dispersion coating of a PHA dispersion on a fibrous substrate. Surprisingly, it has been confirmed that a large amount of the low molecular weight polyol does not adversely affect the barrier properties of the PHA coating. Typically, a dispersant is expected to reduce the barrier properties of the PHA coating and is therefore used in an amount of less than 1% by weight.

[0016] According to a first aspect shown herein, a dispersion coating composition for coating a fibrous substrate, wherein the dispersion coating composition comprises, in a liquid medium, 50 to 99% by weight of polyhydroxyalkanoate (PHA) particles based on the total solids of the dispersion coating composition, and 1 to 50% by weight of a low molecular weight polyol dispersant based on the total solids of the dispersion coating composition, and the total solids of the dispersion coating composition are in the range of 20 to 80% by weight, a dispersion coating composition is provided.

[0017] PHA particles are preferably the main component of the dispersion coating composition based on the dry weight of the composition. In some embodiments, the dispersion coating composition contains at least 50% by weight, at least 65% by weight, at least 70% by weight, or at least 90% by weight of PHA particles based on the total solids content of the dispersion coating composition. In some embodiments, the dispersion coating composition contains 70-99% by weight, preferably 90-99% by weight, of PHA particles based on the total solids content of the dispersion coating composition. In some embodiments, the dispersion coating composition contains 50-97% by weight, 50-95% by weight, 50-92.5% by weight, 50-90% by weight, 50-87.5% by weight, or 50-85% by weight of PHA particles based on the total solids content of the dispersion coating composition. In some embodiments, the dispersion coating composition contains 65-97% by weight, 65-95% by weight, 65-92.5% by weight, 65-90% by weight, 65-87.5% by weight, or 65-85% by weight of PHA particles based on the total solids content of the dispersion coating composition. In some embodiments, the dispersion coating composition contains 70-97% by weight, 70-95% by weight, 70-92.5% by weight, 70-90% by weight, 70-87.5% by weight, or 70-85% by weight of PHA particles based on the total solids content of the dispersion coating composition. In some embodiments, the dispersion coating composition contains 90-97% by weight, 90-95% by weight, or 90-92.5% by weight of PHA particles based on the total solids content of the dispersion coating composition.

[0018] The particle size distribution of PHA particles can be multimodal or unimodal. In some embodiments, PHA particles have a unimodal or bimodal particle size distribution. In some embodiments, PHA particles have a unimodal particle size distribution.

[0019] In some embodiments, the PHA particles have a median particle size (D50) of less than 15 μm, preferably less than 12 μm, more preferably in the range of 0.5 to 11 μm, or in the range of 0.8 to 8 μm.

[0020] In some embodiments, the dispersion coating composition does not contain, or substantially does not contain, particles or particle aggregates having a particle size greater than about 50 μm, greater than about 20 μm, or greater than about 15 μm.

[0021] Unless otherwise specified, all particle sizes and particle size distributions herein are determined by laser diffraction using a Mastersizer 3000 in accordance with ISO 13320:2009.

[0022] In some embodiments, the PHA particles contain 70 to 99.9% by weight, preferably 90 to 99.9% by weight, of PHA based on the dry weight of the PHA particles.

[0023] In some embodiments, PHA is selected from the group consisting of poly(3-hydroxyoctanoate) (PHO), poly(3-hydroxydecanoate) (PHD), poly(3-hydroxyhexanoate) (PHH), and poly(3-hydroxyvalerate) (PHV), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB4HB), poly(3-hydroxyoctanoate-co-3-hydroxyhexanoate) (PHOHH), poly(3-hydroxyoctanoate-co-3-hydroxydecanoate) (PHOHD), and poly(3-hydroxyoctanoate-co-3-hydroxydodecanoate) (PHDHDD), or combinations thereof. Those skilled in the art will understand that PHAs suitable for use in dispersion coating compositions are not limited to those listed herein.

[0024] In some embodiments, PHA is a PHA copolymer.

[0025] In some embodiments, the PHA is selected from the group consisting of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB4HB), poly(3-hydroxyoctanoate-co-3-hydroxyhexanoate) (PHOHH), poly(3-hydroxyoctanoate-co-3-hydroxydecanoate) (PHOHD), and poly(3-hydroxyoctanoate-co-3-hydroxydodecanoate) (PHDHDD), or combinations thereof. Those skilled in the art will understand that PHA copolymers suitable for use in dispersion coating compositions are not limited to those listed herein.

[0026] In some embodiments, the PHA is a medium-chain PHA, preferably a PHA having 6 to 14 carbon atoms per monomer unit.

[0027] The type of PHA suitable for use in dispersion coating compositions can be characterized by its melting point. In some embodiments, the PHA has a melting point in the range of 100 to 170°C, preferably in the range of 120 to 160°C. Unless otherwise specified, the melting points referred to herein are determined by differential scanning calorimetry according to standard ASTM D3418.

[0028] The PHA used in the dispersion coating composition is preferably biodegradable and compostable.

[0029] The dispersion coating composition of the present invention contains 1 to 50% by weight of a low molecular weight polyol dispersant based on the total solids content of the dispersion coating composition. Dispersants are typically low molecular weight polymers used to improve the colloidal stability of dispersions and reduce viscosity (e.g., by reducing floc formation). Dispersants are not typically used to improve the barrier properties of coatings. In fact, many dispersants, especially at higher concentrations, are expected to migrate and reduce the barrier properties of barrier coatings.

[0030] In some embodiments, the dispersion coating composition contains 3 to 35% by weight, more preferably 5 to 30% by weight, of a low molecular weight polyol dispersant based on the total solids content of the dispersion coating composition. In some embodiments, the dispersion coating composition contains 7.5 to 35% by weight, preferably 10 to 35% by weight, more preferably 12.5 to 35% by weight, and more preferably 15 to 35% by weight, of a low molecular weight polyol dispersant based on the total solids content of the dispersion coating composition. In some embodiments, the dispersion coating composition contains 7.5 to 30% by weight, preferably 10 to 30% by weight, more preferably 12.5 to 30% by weight, and more preferably 15 to 30% by weight, of a low molecular weight polyol dispersant based on the total solids content of the dispersion coating composition. In some embodiments, the dispersion coating composition contains 7.5 to 25% by weight, preferably 10 to 25% by weight, more preferably 12.5 to 25% by weight, and more preferably 15 to 25% by weight, of a low molecular weight polyol dispersant based on the total solids content of the dispersion coating composition.

[0031] In some embodiments, the dispersion coating composition comprises 3 to 35% by weight of a low molecular weight polyol dispersant and 65 to 97% by weight of PHA particles, or 5 to 30% by weight of a low molecular weight polyol dispersant and 70 to 95% by weight of PHA particles, based on the total solids content of the dispersion coating composition. In some embodiments, the dispersion coating composition comprises 7.5 to 30% by weight of a low molecular weight polyol dispersant and 70 to 92.5% by weight of PHA particles, or 10 to 30% by weight of a low molecular weight polyol dispersant and 70 to 90% by weight of PHA particles, or 12.5 to 30% by weight of a low molecular weight polyol dispersant and 70 to 87.5% by weight of PHA particles, or 15 to 30% by weight of a low molecular weight polyol dispersant and 70 to 85% by weight of PHA particles, based on the total solids content of the dispersion coating composition.

[0032] In some embodiments, the low molecular weight polyol dispersant has a molecular weight in the range of 50 to 2000 g / mol, preferably in the range of 50 to 1500 g / mol, more preferably in the range of 50 to 1000 g / mol or in the range of 50 to 500 g / mol.

[0033] In some embodiments, the low molecular weight polyol dispersant is selected from the group consisting of low molecular weight polysaccharides and sugar alcohols, as well as combinations thereof.

[0034] In some embodiments, the low molecular weight polyol dispersant is selected from the group consisting of low molecular weight polysaccharides having a degree of polymerization (DP) in the range of 2 to 100, preferably in the range of 2 to 50. In some embodiments, the low molecular weight polyol dispersant is selected from the group consisting of low molecular weight polysaccharides having a degree of polymerization (DP) in the range of 2 to 12. The low molecular weight polysaccharides may be charged, uncharged, amphoteric, or a combination thereof. The low molecular weight polysaccharides may be linear or branched.

[0035] In some embodiments, the low molecular weight polyol dispersant is a sugar alcohol, preferably selected from the group consisting of sorbitol, maltitol, xylitol, mannitol, and glycerol, and combinations thereof. In some embodiments, the low molecular weight polyol dispersant is selected from the group consisting of sorbitol, maltitol, xylitol, mannitol, and combinations thereof. In some embodiments, the low molecular weight polyol dispersant is sorbitol.

[0036] In some embodiments, the dispersion coating composition further comprises 0.01 to 15% by weight, preferably 0.01 to 10% by weight, and more preferably 0.1 to 5% by weight, of a rheological modifier based on the total solids content of the dispersion coating composition. The rheological modifier is used to adjust the viscosity and water retention of the dispersion coating composition to suit application by preferred application methods.

[0037] In some embodiments, the rheological modifier includes a polymer selected from the group consisting of polysaccharides, polysaccharide derivatives, polypeptides, polypeptide derivatives, or combinations thereof.

[0038] In some embodiments, the dispersion coating composition further comprises 1 to 30% by weight of filler particles based on the total solids content of the dispersion coating composition. Too many filler particles can lead to cracking and reduced barrier properties. The amount of filler particles is preferably 5 to 25% by weight, more preferably 5 to 15% by weight, based on the total solids content of the dispersion coating composition.

[0039] In some embodiments, the filler particles are selected from the group consisting of clay (such as kaolin or calcined kaolin), talcam, CaCO3 (such as PCC or GCC), TiO2, Al2O3, SiO2, bentonite, fibers, phyllosilicates, or combinations thereof. The filler particles are preferably high aspect ratio filler particles, for example, flake particles having a median particle size (D90) of less than 2 μm.

[0040] In some embodiments, the dispersion coating composition comprises, based on the total solids content of the dispersion coating composition, at least 50% by weight of polyhydroxyalkanoate (PHA) particles, an amount of low molecular weight polyol dispersant as disclosed herein, optionally an amount of rheological modifier as disclosed herein, and optionally an amount of filler particles as disclosed herein. In some embodiments, the dispersion coating composition comprises, based on the total solids content of the dispersion coating composition, at least 70% by weight of polyhydroxyalkanoate (PHA) particles, 7.5 to 30% by weight of low molecular weight polyol dispersant, 0.1 to 5% by weight of rheological modifier, and optionally 5 to 25% by weight of filler particles.

[0041] In some embodiments, the dispersion coating composition may also include further additives such as lubricants, humectants or softeners, sizing agents, dehydration accelerators, slime inhibitors, wetting strength agents, pH adjusters, defoamers, crosslinking agents, biocides, preservatives, and / or colorants.

[0042] In some embodiments, the dispersion coating composition does not contain any foaming agent, such as a nonpolymer or polymer surfactant. In some embodiments, the dispersion coating composition contains less than 0.5% by weight, preferably less than 0.1% by weight, and more preferably less than 0.01% by weight, an added foaming agent, such as a nonpolymer or polymer surfactant.

[0043] In some embodiments, the dispersion coating composition is degassed. Low molecular weight polyol dispersants are advantageous in this respect because they are less likely to trap air bubbles than high molecular weight dispersants. Therefore, in some embodiments, the dispersion coating composition is preferably free of or substantially free of air and other gas bubbles.

[0044] In some embodiments, the dispersion coating composition has a total solids content in the range of 30 to 70% by weight, preferably in the range of 40 to 60% by weight.

[0045] In some embodiments, the dispersion coating composition has a viscosity in the range of 50 to 4000 mPas, preferably in the range of 250 to 3500 mPas, determined according to SCAN-P50:84 using a Brookfield viscometer equipped with an LV-4 spindle at a rotational speed of 100 rpm.

[0046] In some embodiments, the dispersion coating composition is determined according to TAPPI T701pm-0, at 250 g / m². 2 Less than 200 g / m², preferably 200 g / m² 2 Less than 50-150 g / m² is preferable. 2 It has an ÅAGWR water retention value (Åbo Akademi water retention value) in the range of [value].

[0047] The liquid medium may include water, an organic solvent, or a mixture of water and an organic solvent. In some embodiments, the liquid medium is water.

[0048] The dispersion coating composition according to the first embodiment described herein enables the preparation of improved PHA-coated fiber-based substrates.

[0049] According to a second embodiment shown herein, a dispersion-coated fiber substrate, A fibrous substrate having a first main surface and a second main surface, It includes a dispersion coating layer on a first main surface, and the dispersion coating layer is Based on the total solid content of the dispersion coating layer, 50-99% by weight of polyhydroxyalkanoate (PHA) particles, and 1 to 50% by weight of low molecular weight polyol dispersant based on the total solid content of the dispersion coating layer A dispersion-coated fiber substrate is provided, which includes the above.

[0050] The fibrous substrate (also referred to herein as the “substrate”) is preferably a sheet or web of material mainly formed from pulp of wood or other fibrous material. In some embodiments, the fibrous substrate is paper or cardboard, preferably cardboard.

[0051] Paper generally refers to a material manufactured in sheets or rolls from pulp of wood or other fibrous materials, including cellulose fibers, and is used, for example, for writing, drawing, printing, or as packaging material. Paper can be bleached or unbleached, depending on the requirements of its end use, and can be manufactured in various thicknesses.

[0052] Cardboard generally refers to strong cardboard or corrugated cardboard containing cellulose fibers, used, for example, as a flat substrate, tray, box, and / or other types of packaging. Depending on the requirements of the end use, cardboard can be either bleached or unbleached and can be manufactured in various thicknesses.

[0053] In some embodiments, the fibrous substrate is composed of two or more cellulosic layers. Each of the cellulosic layers can have a specific composition of pulp fibers such as bleached and / or unbleached kraft pulp, sulfite pulp, dissolving pulp, thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP), pressure groundwood pulp (PGW), high-temperature CTMP (HT-CTMP), broke, recycled fibers such as pre- and post-consumer waste, and / or mixtures thereof. Different layers can have different basis weights and / or thicknesses and can contain different amounts of additives such as internal sizing agents.

[0054] As an example, the fibrous substrate can be composed of an upper layer of one layer of bleached or unbleached kraft pulp, an intermediate layer of a mixture of bleached or unbleached kraft pulp and CTMP, and a lower layer of bleached or unbleached kraft pulp, and the intermediate layer has a higher thickness and / or lower density than both the upper and lower layers.

[0055] A preferred fibrous substrate is a paper or board having a high content of unbleached fibers, such as at least 50 wt% in at least one of the layers, thus forming a rough surface, but having good mechanical properties and a natural appearance.

[0056] In some embodiments, the basis weight of the fibrous substrate is in the range of 20 - 800 g / m 2 In some embodiments, the fibrous substrate has a basis weight of at least 100 g / m 2 In some embodiments, the fibrous substrate has a basis weight of at least 150 g / m 2 , 200 g / m 2 , 250 g / m 2 , 300 g / m 2 , 350 g / m 2 , or 400 g / m 2 . The basis weight of the fibrous substrate is preferably less than 1000 g / m 2 , less than 800 g / m 2 , or less than 600 g / m 2It is less than [amount missing]. Unless otherwise specified, the basis weight is determined according to standard ISO 536.

[0057] The fibrous substrate may also be surface-sized or impregnated. In some embodiments, the fibrous substrate may be surface-sized or impregnated on one or both sides with a surface-sizing composition, preferably comprising a starch derivative, a cellulose derivative, or polyvinyl alcohol (PVOH) or a combination thereof. The starch derivative may be lightly modified, for example, oxidized starch or cationized starch. The cellulose derivative may be sodium carboxymethylcellulose having a degree of substitution greater than 0.4, for example, in the range of 0.5 to 1.5. PVOH may be completely or partially hydrolyzed. The surface-sizing composition may also contain hydrophobic sizing agents such as alkyl ketene dimer (AKD), alkenyl succinic anhydride (ASA), or rosin sizing agents. It is preferable that the fibrous substrate is surface-sized or impregnated on the first main surface to which the dispersion coating is applied. Surface sizing or impregnation can provide a more uniform and less water-absorbent surface for the dispersion coating composition. Surface sizing or impregnation treatment may also promote the release of the PHA coating structure from the fibrous substrate during repulping.

[0058] In some embodiments, the basis weight of the surface sizing composition is 0.2 to 10 g / m² per side, based on dry weight. 2 Preferably 0.4 to 8 g / m 2 , more preferably 0.8~5 g / m 2 That is the case.

[0059] The fibrous substrate itself may have relatively high permeability to liquids such as water, oil, and grease, water vapor, and gases such as oxygen, air, and carbon dioxide, prior to PHA coating. In some embodiments, the fibrous substrate has a density of at least 200 g / m², as measured according to standard ASTM F1249-20 at 50% relative humidity and 23°C. 2It has a water vapor transmission rate (WVTR) of 100 g / m² / 24h. In some embodiments, the fibrous substrate is measured according to the standard ISO 535:2014 and has a density of 100 g / m². 2 Less than 80 g / m² 2 Less than 60g / m² 2 Less than 40g / m² 2 It has a COBB60 value of less than .

[0060] Before PHA coating, the fibrous substrate itself is determined according to ISO 2493-1, L&W (15 o Preferably, the bending resistance is at least 145 mN(MD).

[0061] PHA particles are preferably the main component of the dispersion coating layer based on the total solid content of the dispersion coating layer. In some embodiments, the dispersion coating layer contains at least 50% by weight, at least 65% by weight, at least 70% by weight, or at least 90% by weight of PHA particles based on the total solid content of the dispersion coating layer. In some embodiments, the dispersion coating layer contains 70-99% by weight, preferably 90-99% by weight, of PHA particles based on the total solid content of the dispersion coating layer. In some embodiments, the dispersion coating layer contains 50-97% by weight, 50-95% by weight, 50-92.5% by weight, 50-90% by weight, 50-87.5% by weight, or 50-85% by weight of PHA particles based on the total solid content of the dispersion coating layer. In some embodiments, the dispersion coating layer contains 65-97% by weight, 65-95% by weight, 65-92.5% by weight, 65-90% by weight, 65-87.5% by weight, or 65-85% by weight of PHA particles based on the total solid content of the dispersion coating layer. In some embodiments, the dispersion coating layer contains 70-97% by weight, 70-95% by weight, 70-92.5% by weight, 70-90% by weight, 70-87.5% by weight, or 70-85% by weight of PHA particles based on the total solid content of the dispersion coating layer. In some embodiments, the dispersion coating layer contains 90-97% by weight, 90-95% by weight, or 90-92.5% by weight of PHA particles based on the total solid content of the dispersion coating layer.

[0062] The particle size distribution of PHA particles can be multimodal or unimodal. In some embodiments, PHA particles have a unimodal or bimodal particle size distribution. In some embodiments, PHA particles have a unimodal particle size distribution.

[0063] In some embodiments, the PHA particles have a median particle size (D50) of less than 15 μm, preferably less than 12 μm, more preferably in the range of 0.5 to 11 μm, or in the range of 0.8 to 8 μm.

[0064] In some embodiments, the dispersion coating layer does not contain, or substantially does not contain, particles or particle aggregates having particle sizes greater than about 50 μm, greater than about 20 μm, or greater than about 15 μm.

[0065] In some embodiments, the PHA particles contain 70 to 99.9% by weight, preferably 90 to 99.9% by weight, of PHA based on the dry weight of the PHA particles.

[0066] In some embodiments, PHA is selected from the group consisting of poly(3-hydroxyoctanoate) (PHO), poly(3-hydroxydecanoate) (PHD), poly(3-hydroxyhexanoate) (PHH), and poly(3-hydroxyvalerate) (PHV), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB4HB), poly(3-hydroxyoctanoate-co-3-hydroxyhexanoate) (PHOHH), poly(3-hydroxyoctanoate-co-3-hydroxydecanoate) (PHOHD), and poly(3-hydroxyoctanoate-co-3-hydroxydodecanoate) (PHDHDD), or combinations thereof.

[0067] In some embodiments, PHA is a PHA copolymer.

[0068] In some embodiments, PHA is selected from the group consisting of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB4HB), poly(3-hydroxyoctanoate-co-3-hydroxyhexanoate) (PHOHH), poly(3-hydroxyoctanoate-co-3-hydroxydecanoate) (PHOHD), and poly(3-hydroxyoctanoate-co-3-hydroxydodecanoate) (PHDHDD), or combinations thereof.

[0069] In some embodiments, the PHA is a medium-chain PHA, preferably a PHA having 6 to 14 carbon atoms per monomer unit.

[0070] In some embodiments, PHA has a melting point in the range of 100 to 170°C, preferably in the range of 120 to 160°C.

[0071] In some embodiments, the dispersion coating layer contains 3 to 35% by weight, more preferably 5 to 30% by weight, of a low molecular weight polyol dispersant based on the total solids content of the dispersion coating layer. In some embodiments, the dispersion coating layer contains 7.5 to 35% by weight, preferably 10 to 35% by weight, more preferably 12.5 to 35% by weight, and more preferably 15 to 35% by weight, of a low molecular weight polyol dispersant based on the total solids content of the dispersion coating layer. In some embodiments, the dispersion coating layer contains 7.5 to 30% by weight, preferably 10 to 30% by weight, more preferably 12.5 to 30% by weight, and more preferably 15 to 30% by weight, of a low molecular weight polyol dispersant based on the total solids content of the dispersion coating layer. In some embodiments, the dispersion coating layer contains 7.5 to 25% by weight, preferably 10 to 25% by weight, more preferably 12.5 to 25% by weight, and more preferably 15 to 25% by weight, of a low molecular weight polyol dispersant based on the total solids content of the dispersion coating layer.

[0072] In some embodiments, the dispersion coating layer comprises 3 to 35% by weight of a low molecular weight polyol dispersant and 65 to 97% by weight of PHA particles, or 5 to 30% by weight of a low molecular weight polyol dispersant and 70 to 95% by weight of PHA particles, based on the total solid content of the dispersion coating layer. In some embodiments, the dispersion coating layer comprises 7.5 to 30% by weight of a low molecular weight polyol dispersant and 70 to 92.5% by weight of PHA particles, or 10 to 30% by weight of a low molecular weight polyol dispersant and 70 to 90% by weight of PHA particles, or 12.5 to 30% by weight of a low molecular weight polyol dispersant and 70 to 87.5% by weight of PHA particles, or 15 to 30% by weight of a low molecular weight polyol dispersant and 70 to 85% by weight of PHA particles, based on the total solid content of the dispersion coating layer.

[0073] In some embodiments, the low molecular weight polyol dispersant has a molecular weight in the range of 50 to 2000 g / mol, preferably in the range of 50 to 1500 g / mol, more preferably in the range of 50 to 1000 g / mol or in the range of 50 to 500 g / mol.

[0074] In some embodiments, the low molecular weight polyol dispersant is selected from the group consisting of low molecular weight polysaccharides and sugar alcohols, as well as combinations thereof.

[0075] In some embodiments, the low molecular weight polyol dispersant is selected from the group consisting of low molecular weight polysaccharides having a degree of polymerization (DP) in the range of 2 to 100, preferably in the range of 2 to 50. In some embodiments, the low molecular weight polyol dispersant is selected from the group consisting of low molecular weight polysaccharides having a degree of polymerization (DP) in the range of 2 to 12. The low molecular weight polysaccharides may be charged, uncharged, amphoteric, or a combination thereof. The low molecular weight polysaccharides may be linear or branched.

[0076] In some embodiments, the low molecular weight polyol dispersant is a sugar alcohol, preferably selected from the group consisting of sorbitol, maltitol, xylitol, mannitol, and glycerol, and combinations thereof. In some embodiments, the low molecular weight polyol dispersant is selected from the group consisting of sorbitol, maltitol, xylitol, mannitol, and combinations thereof. In some embodiments, the low molecular weight polyol dispersant is sorbitol.

[0077] In some embodiments, the dispersion-coated fiber substrate further comprises 0.01 to 15% by weight, preferably 0.01 to 10% by weight, and more preferably 0.1 to 5% by weight, of a rheological modifier based on the total solid content of the dispersion coating layer.

[0078] In some embodiments, the rheological modifier includes a polymer selected from the group consisting of polysaccharides, polysaccharide derivatives, polypeptides, polypeptide derivatives, or combinations thereof.

[0079] In some embodiments, the dispersion-coated fiber substrate further comprises 1 to 30% by weight of filler particles based on the total solid content of the dispersion coating layer.

[0080] In some embodiments, the filler particles are selected from the group consisting of clay, talcam, CaCO3, TiO2, Al2O3, SiO2, bentonite, fibers, phyllosilicates, or combinations thereof.

[0081] In some embodiments, the dispersion coating layer comprises, based on the total solids content of the dispersion coating layer, at least 50 wt% polyhydroxyalkanoate (PHA) particles, a low molecular weight polyol dispersant in an amount disclosed herein, optionally a rheological modifier in an amount disclosed herein, and optionally a filler particle in an amount disclosed herein. In some embodiments, the dispersion coating layer comprises, based on the total solids content of the dispersion coating layer, at least 70 wt% polyhydroxyalkanoate (PHA) particles, 7.5 to 30 wt% low molecular weight polyol dispersant, 0.1 to 5 wt% rheological modifier, and optionally 5 to 25 wt% filler particles.

[0082] In some embodiments, the dispersion coating layer does not contain any foaming agent, such as a nonpolymer or polymer surfactant. In some embodiments, the dispersion coating layer contains less than 0.5% by weight, preferably less than 0.1% by weight, and more preferably less than 0.01% by weight, an added foaming agent, such as a nonpolymer or polymer surfactant.

[0083] In some embodiments, the dispersion coating layer is degassed. Therefore, in some embodiments, the dispersion coating layer is preferably free of or substantially free of air and other gas bubbles.

[0084] In some embodiments, the dispersion coating layer is 5-40 g / m². 2 In the range of 5-30 g / m², preferably 5-30 g / m² 2 In the range of 5-20 g / m², more preferably 5-20 g / m² 2 It has a basis weight in the range of [range]. In some embodiments, the dispersion coating layer has a thickness in the range of 8 to 20 μm.

[0085] In some embodiments, the dispersion-coated fiber substrate is determined according to ISO 2493-1, L&W(15 o Preferably, the bending resistance is at least 145 mN(MD).

[0086] In some embodiments, the dispersion-coated fiber substrate further includes a heat-fusible liquid barrier layer on a second main surface.

[0087] In some embodiments, it may be preferable to coat both main surfaces of the fibrous substrate with a PHA dispersion coating. Therefore, in some embodiments, the dispersion-coated fibrous substrate further includes a dispersion coating layer on a second main surface, and the dispersion coating layer is Based on the total solid content of the dispersion coating layer, 50-99% by weight of polyhydroxyalkanoate (PHA) particles, and 1 to 50% by weight of low molecular weight polyol dispersant based on the total solid content of the dispersion coating layer Includes.

[0088] The dispersion coating layer on the second main surface may be further defined as the dispersion coating layer on the first main surface. The dispersion coating layer on the second main surface may be identical to or different from the dispersion coating layer on the first main surface.

[0089] In some embodiments, the dispersion-coated fiber substrate was measured at 50% relative humidity and 23°C according to standard ASTM F1249-20 to 25 g / m². 2 Less than 24 hours, preferably 20 g / m² 2 Less than 24 hours, more preferably 17 g / m² 2 It has a water vapor transmission rate (WVTR) of less than / 24h.

[0090] In some embodiments, the dispersion-coated first main surface of the dispersion-coated fibrous substrate is measured according to standard ISO 535:2014 to 25 g / m². 2 Less than 20 g / m², preferably 20 g / m² 2 Less than 15 g / m², more preferably 15 g / m² 2 It has a COBB600 value of less than 600.

[0091] In some embodiments, the dispersion-coated first main surface of the dispersion-coated fibrous substrate has a KIT value of at least 5, preferably at least 10, as measured according to TAPPI standard T 559.

[0092] In some embodiments, the dispersion-coated first main surface of the dispersion-coated fibrous substrate is free of pinholes. The number of pinholes can be determined by optical inspection, for example, according to standard EN13676:2001. The substrate film is measured according to standard EN13676:2001, preferably 10 pinholes / m². 2 Less than 8 pieces / m 2 Less than, more preferably 2 pieces / m 2 Includes pinholes smaller than 1.

[0093] Dispersion-coated fibrous substrates can be recycled into other paper products using common repulping techniques. In repulping, the cellulose fibers of the fibrous substrate are separated from a non-repulpable fraction called the impurity. The impurity may include, for example, aggregated fibers and solid foreign matter that need to be removed for disposal or conversion into energy. In some embodiments, the dispersion-coated fibrous substrate has repulpability characterized by an impurity rate of less than 20%, preferably less than 10%, and more preferably less than 5%, as determined according to the PTS RH 021 / 97 test method for Category II products. Thus, the dispersion-coated fibrous substrate offers very good repulpability. Therefore, the dispersion-coated fibrous substrate can be referred to as a repulpable material.

[0094] In some embodiments, the dispersed coating fiber substrate is biodegradable and compostable according to standard EN 13432.

[0095] According to a third aspect described herein, a method for producing a dispersion-coated fiber substrate, wherein the method is a) A step of preparing a fibrous substrate having a first main surface and a second main surface, b) A step of forming a dispersion coating layer by applying a dispersion coating composition defined with reference to the first embodiment to a first main surface and drying the applied dispersion coating composition; A method is provided that includes this.

[0096] In some embodiments, the method is c) further comprising forming a heat-fusible liquid barrier on a second main surface.

[0097] In some embodiments, the dispersion coating composition is further defined as described herein with reference to the first embodiment.

[0098] In some embodiments, the fibrous substrate is further defined as described herein with reference to a second embodiment.

[0099] The method of the present invention can be carried out online on a full-scale paper machine or paperboard manufacturing machine.

[0100] The dispersion coating layer is preferably formed by a liquid film coating process, in which the dispersion coating composition is applied to the substrate, spread into a thin, uniform layer, and then dried.

[0101] In some embodiments, the dispersion coating composition is 5-40 g / m² based on dry weight. 2 In the range of 5-30 g / m², preferably 5-30 g / m² 2 In the range of 5-20 g / m², more preferably 5-20 g / m² 2 It is applied in basis weights within the range of [range]. The thickness of the wet dispersion coating composition when applied to a substrate is typically in the range of 20 to 100 μm, preferably in the range of 20 to 50 μm. Therefore, it is preferable that the dispersion coating composition does not contain particles or particle aggregates larger than 20 to 50 μm. Thus, in some embodiments, the dispersion coating composition does not contain, or substantially does not contain, particles or particle aggregates having particle sizes greater than about 50 μm, greater than about 20 μm, or greater than about 15 μm.

[0102] In some embodiments, the dispersion coating composition is applied by a non-contact application method. In some embodiments, the dispersion coating composition is applied by an application method selected from the group consisting of roller coating, spray coating, curtain, blade coating, slot coating, dipping coating, gravure roll coating, reverse direct gravure coating, rod coating, soft tip blade coating, short dwell, and soft tip rod coating, and combinations thereof. In some embodiments, the dispersion coating composition is applied by blade coating or rod coating. The dispersion coating composition may be applied directly to a fibrous substrate or indirectly, for example, via a transfer roll or belt.

[0103] To minimize the risk of pinholes in the dispersion coating layer, the dispersion coating layer may be formed by applying the dispersion coating composition in two or more steps, with pre-drying between steps. In such embodiments, the dispersion coating composition in each step is 5 to 10 g / m² based on dry weight. 2 It can be applied in basis weights within the range of [specify range]. In some embodiments, the dispersion coating composition applied in the first step may be different from the dispersion coating composition applied in the second step. In some embodiments, the PHA particles in the dispersion coating composition applied in the second step have a median particle size smaller than the median particle size of the particles in the dispersion coating composition applied in the first step. In some embodiments, the median particle size of the PHA in the second step is at least 10% smaller, preferably at least 20% smaller, and more preferably at least 30% smaller than the median particle size of the PHA in the first step.

[0104] In some embodiments, drying includes subjecting the dispersion coating composition to heating. In some embodiments, drying includes subjecting the dispersion coating composition to at least one non-contact drying step, such as hot air with infrared radiation, electron beam radiation, ultraviolet radiation, microwave radiation, impingement, or a combination thereof. Optionally, the dispersion coating composition is then subjected to at least one further drying step, which may be a hot air drying step or a contact drying step, such as heat conduction drying using a heating belt or heating cylinder.

[0105] In some embodiments, the dry dispersion coating layer is 5-40 g / m². 2 In the range of 5-30 g / m², preferably 5-30 g / m² 2 In the range of 5-20 g / m², more preferably 5-20 g / m² 2 It has a basis weight in the range of [value]. In some embodiments, the dry dispersion coating layer has a thickness in the range of 8 to 20 μm.

[0106] In some embodiments, the resulting dispersion-coated fiber substrate is further defined as described herein with reference to a second embodiment.

[0107] In some embodiments, both the fibrous substrate provided in a) and the dispersion-coated fibrous substrate obtained in b) are determined according to ISO 2493-1, and contain at least 145 mN(MD) L&W(15 o It has bending resistance.

[0108] A fourth aspect of this specification provides a packaging container comprising a dispersion-coated fiber substrate as defined by reference to the second aspect.

[0109] The dispersion coating layer of the dispersion-coated fiber substrate of the present invention has been found to be particularly useful as a moisture / liquid barrier for use on the outer surface of food and liquid packaging containers. Therefore, in some embodiments, the dispersion-coated first main surface forms the outer surface of the container.

[0110] The packaging containers are particularly useful for liquids, oily foods, dry foods, and / or frozen foods. In some embodiments, the packaging is a beverage container, preferably a cup.

[0111] In some embodiments, the packaging container is biodegradable and compostable in accordance with standard EN 13432.

[0112] The dispersion-coated fiber substrates of this disclosure preferably exhibit some or all of the following characteristics: - Small coating amount, preferably 5-20 g / m² 2 Coating amount within the range - A dispersion coating layer that is virtually pinhole-free - Low COBB600 value, preferably 25 g / m² 2 COBB600 value less than - Grease resistance, preferably a KIT value > 10. - Good crack resistance - The percentage of repulped PTS nonconformities, as determined according to the PTS RH 021 / 97 test method for Category II products, is preferably less than 20%. - Compostable for home and industrial use -Printable

[0113] Generally, products, polymers, materials, layers, and processes are described using the term "contains" various components or processes, but products, polymers, materials, layers, and processes can also "essentially consist of" or "be made of" various components and processes.

[0114] Although the present invention has been described with reference to various exemplary embodiments, it will be understood by those skilled in the art that various modifications can be made and elements can be replaced with equivalents without departing from the scope of the invention. Furthermore, many modifications can be made to adapt the teachings of the invention to specific situations or materials without departing from the essential scope of the invention. Thus, the present invention is not limited to the specific embodiments disclosed as the best mode intended to carry out the invention, and the invention is intended to include all embodiments that fall within the scope of the appended claims. [Examples]

[0115] A series of tests were conducted to evaluate the dispersion coating compositions of the present invention. Dispersion coating compositions were prepared by adding dry PHA to an aqueous solution containing a dispersant, followed by the addition of other components. All percentages were calculated as dry solids content (weight%).

[0116] Example 1 (Comparative Example) - PVOH as a dispersant containing filler particles A poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) dispersion containing a PVOH-based dispersant was prepared, and filler particles were added (see Table 1, Criterion 1). The dispersion exhibited poor stability, a granular texture, and uneven coating quality. The dispersion coating composition was applied to one side of a cardboard sheet using a pilot rod coater, and the barrier properties and rigidity of the coated cardboard sheet were evaluated. The cardboard sheet was coated in two steps, with intermediate drying between steps. The COBB600 value was high, indicating insufficient moisture barrier properties. The dispersion coating composition generated a large amount of foam during preparation and during the subsequent defibration of the sample sheet.

[0117] Example 2 (Comparative Example) - PVOH as a dispersant without filler particles A poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) dispersion containing a PVOH-based dispersant was prepared (see Table 1, Criterion 2). The dispersion exhibited poor stability, a granular texture, and uneven coating quality. The dispersion coating composition was applied to cardboard using a pilot rod coater, and the barrier properties and rigidity of the coated cardboard were evaluated. One side of the cardboard was coated in two steps, with intermediate drying between steps. The COBB600 value was high, indicating insufficient moisture barrier properties. The dispersion coating composition generated a large amount of foam during preparation and during subsequent defibration of the sample sheet.

[0118] Example 3 - Sorbitol as a dispersant without filler particles A poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) dispersion containing sorbitol as a dispersant was prepared (see Table 1, Dispersion 1). A rheology modifier (water-soluble polysaccharide) was added to the dispersion, and a small amount of defoamer was added to suppress bubbles in the dispersion caused by vigorous mixing during dispersion preparation. The dispersion exhibited good stability, resulting in uniform coating quality. The dispersion coating composition was coated onto cardboard using a pilot rod coater, and the barrier properties and rigidity of the coated cardboard were evaluated. One side of the cardboard was coated in two steps, with intermediate drying between steps. The COBB600 value was low, indicating good moisture barrier properties. Grease resistance, measured by the KIT method according to TAPPI standard T 559, was within acceptable limits. The dispersion coating composition did not generate bubbles during preparation or during subsequent defibration of the sample sheet.

[0119] Example 4 - Sorbitol as a dispersant containing filler particles A poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) dispersion containing sorbitol as a dispersant was prepared (see Table 1, Dispersion 2). Rheology modifiers and filler particles were added to the dispersion, and a small amount of defoamer was added to suppress bubbles in the dispersion caused by vigorous mixing during dispersion preparation. The dispersion exhibited good stability, resulting in uniform coating quality. The dispersion coating composition was coated onto cardboard using a pilot rod coater, and the barrier properties and rigidity of the coated cardboard were evaluated. One side of the cardboard was coated in two steps, with intermediate drying between steps. The coatings on the cardboard were prepared as shown in Table 2. The COBB600 value was low, indicating good moisture barrier properties. The KIT value was good. The dispersion coating composition did not generate bubbles during preparation or during subsequent defibration of the sample sheet.

[0120] Example 5 - Different dispersion coating compositions The dispersion coating composition was coated onto cardboard using a pilot rod coater, and the barrier properties and rigidity of the coated cardboard were evaluated. The coating was applied to one side of the cardboard in two steps, with intermediate drying between steps. Dispersion 1 from Example 3 was used in the first coating step, and dispersion 2 from Example 4 was used in the second coating step, as shown in Table 2. The COBB600 values ​​were low, indicating good moisture barrier properties. KIT was within the acceptable range. The dispersion coating composition did not generate bubbles during preparation or during subsequent defibration of the sample sheet. Table 1 - Dispersion Coating Compositions TIFF2026509900000001.tif66170 Table 2 - Dispersion-coated paperboard samples TIFF2026509900000002.tif46170

Claims

1. A dispersion coating composition for coating a fibrous substrate, wherein the dispersion coating composition is in a liquid medium, Based on the total solid content of the dispersion coating composition, 50 to 99% by weight of PHA (polyhydroxyalkanoate) particles, and The dispersion coating composition contains 1 to 50% by weight of a low molecular weight polyol dispersant based on the total solids content. A dispersion coating composition in which the total solid content of the dispersion coating composition is in the range of 20 to 80% by weight.

2. The dispersion coating composition according to claim 1, wherein the PHA particles have a unimodal particle size distribution.

3. The dispersion coating composition according to claim 1 or 2, wherein the PHA particles have a median particle size (D50) of less than 15 μm, preferably less than 12 μm, more preferably in the range of 0.5 to 11 μm, or in the range of 0.8 to 8 μm.

4. The dispersion coating composition according to any one of claims 1 to 3, wherein the dispersion coating composition does not contain or substantially contains particles or particle aggregates having a particle size greater than about 50 μm, greater than about 20 μm, or greater than about 15 μm.

5. The dispersion coating composition according to any one of claims 1 to 4, wherein the PHA particles contain 70 to 99.9% by weight, preferably 90 to 99.9% by weight, of PHA based on the dry weight of the PHA particles.

6. PHA is poly(3-hydroxyoctanoate) (PHO), poly(3-hydroxydecanoate) (PHD), poly(3-hydroxyhexanoate) (PHH), and poly(3-hydroxyvalerate) (PHV), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), poly(3-hydroxybutyrate-co-4-hydroxy A dispersion coating composition according to any one of claims 1 to 5, selected from the group consisting of sibutyrate (P3HB4HB), poly(3-hydroxyoctanoate-co-3-hydroxyhexanoate) (PHOHH), poly(3-hydroxyoctanoate-co-3-hydroxydecanoate) (PHOHD), and poly(3-hydroxyoctanoate-co-3-hydroxydodecanoate) (PHHDHDD), or a combination thereof.

7. The dispersion coating composition according to any one of claims 1 to 6, wherein the dispersion coating composition comprises 3 to 35% by weight, more preferably 5 to 30% by weight, of a low molecular weight polyol dispersant based on the total solid content of the dispersion coating composition.

8. The dispersion coating composition according to any one of claims 1 to 7, wherein the low molecular weight polyol dispersant has a molecular weight in the range of 50 to 2000 g / mol, preferably in the range of 50 to 1500 g / mol, more preferably in the range of 50 to 1000 g / mol or in the range of 50 to 500 g / mol.

9. The dispersion coating composition according to any one of claims 1 to 8, wherein the low molecular weight polyol dispersant is selected from the group consisting of low molecular weight polysaccharides and sugar alcohols, and combinations thereof.

10. A fibrous substrate having a first main surface and a second main surface, It includes a dispersion coating layer on a first main surface, and the dispersion coating layer is Based on the total solid content of the dispersion coating layer, 50 to 99% by weight of PHA (polyhydroxyalkanoate) particles, and 1 to 50% by weight of low molecular weight polyol dispersant based on the total solid content of the dispersion coating layer including Dispersion-coated fiber-based substrate.

11. The dispersion coating layer comprises 3 to 35% by weight, more preferably 5 to 30% by weight, of a low molecular weight polyol dispersant based on the total solid content of the dispersion coating layer, as described in claim 10.

12. The dispersion-coated fiber substrate according to claim 10 or 11, wherein the low molecular weight polyol dispersant has a molecular weight in the range of 50 to 2000 g / mol, preferably in the range of 50 to 1500 g / mol, more preferably in the range of 50 to 1000 g / mol or in the range of 50 to 500 g / mol.

13. The dispersion-coated fiber substrate according to any one of claims 10 to 12, wherein the low molecular weight polyol dispersant is selected from the group consisting of low molecular weight polysaccharides and sugar alcohols, and combinations thereof.

14. A method for producing a dispersion-coated fiber substrate, wherein the method is a) A step of preparing a fibrous substrate having a first main surface and a second main surface, b) A step of forming a dispersion coating layer by applying the dispersion coating composition according to any one of claims 1 to 9 to a first main surface and drying the applied dispersion coating composition; Methods that include...

15. A packaging container comprising a dispersion-coated fiber-based substrate according to any one of claims 10 to 13.

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