Aqueous polymer dispersion

Abstract

A method for producing an aqueous polymer dispersion and an aqueous polymer dispersion are provided. A method for coating a substrate with a composition containing the polymer dispersion is also provided.

Description

[Technical Field]

[0001] The present invention generally relates to a method for producing an aqueous polymer dispersion and to an aqueous polymer dispersion, and more particularly to a method for coating a substrate with a composition containing the aqueous polymer dispersion to achieve barrier properties. [Background technology]

[0002] This section does not consider any of the technologies described herein to represent the latest technologies, but rather provides useful background information as an example.

[0003] Packaging materials must be safe, allow for long-term storage, and reduce food loss. Packaging materials can range from polymers to metals. Often, fiber-based materials are used for food packaging. However, due to the hydroxyl groups within cellulose fibers, these materials are hydrophilic, and therefore require one or more barrier coating layers. Furthermore, for fiber-based packaging to meet the requirements for protecting products, it is crucial that the material possesses a certain level of barrier performance accompanied by one or more barrier coating layers. These barrier materials typically need to provide protection against oxygen, carbon dioxide, moisture, and grease. Examples of such packaging include corrugated cardboard, paperboard, wrapping paper, trays, bowls, and cups.

[0004] Various compositions and techniques have been developed for coating films / layers on packaging materials to improve their moisture and oil resistance. One of the most common methods is the extrusion coating method, which involves applying (one or more) polyolefin-based plastic layers to a fiber-based substrate.

[0005] Due to the growing demand for sustainable alternatives to fossil fuel-derived polymers, other coating methods and compositional solutions need to be developed. Furthermore, packaging with sufficient moisture and grease barrier properties is also required. [Overview of the project]

[0006] The following is a simplified overview of the features disclosed herein to provide a basic understanding of some exemplary embodiments of the present invention. This overview is not a comprehensive overview of the present invention. It is not intended to identify the main / important elements of the present invention or to limit its scope. Its sole purpose is to present some of the concepts disclosed herein in a simplified form as a prelude to a more detailed explanation.

[0007] In a first aspect, the present invention provides a method for producing a polymer dispersion, the method being (a) A step of polymerizing an acrylate monomer in the presence of wax to produce a polymer dispersion; (b) A step of polymerizing acrylate monomers to produce a polymer material, and introducing wax into the polymer material to produce a polymer dispersion; (c) A step of polymerizing an acrylate monomer in the presence of a first wax to produce a polymer material, and introducing a second wax into the polymer material to produce a polymer dispersion; (d) A step of polymerizing acrylate monomers in the presence of a first wax and a second wax to produce a polymer dispersion; or (e) The process includes the steps of polymerizing an acrylate monomer in the presence of a first wax to produce a polymer material (A), polymerizing an acrylate monomer in the presence of a second wax to produce a polymer material (B), and mixing polymer material (A) and polymer material (B) to produce a polymer dispersion.

[0008] In a second aspect, the present invention is (a) A step of polymerizing an acrylate monomer in the presence of wax to produce a polymer dispersion; (b) A step of polymerizing acrylate monomers to produce a polymer material, and introducing wax into the polymer material to produce a polymer dispersion; (c) A step of polymerizing an acrylate monomer in the presence of a first wax to produce a polymer material, and introducing a second wax into the polymer material to produce a polymer dispersion; (d) A step of polymerizing acrylate monomers in the presence of a first wax and a second wax to produce a polymer dispersion; or (e) A polymer dispersion is provided, formed by the steps of (e) polymerizing an acrylate monomer in the presence of a first wax to produce a polymer material (A), polymerizing an acrylate monomer in the presence of a second wax to produce a polymer material (B), and mixing polymer material (A) and polymer material (B) to produce a polymer dispersion.

[0009] In a third aspect, the present invention provides a use for coating at least one layer on at least a portion of at least one surface of a substrate with a polymer dispersion produced by the method of the present invention, or a composition comprising the polymer dispersion of the present invention and optionally additional agents.

[0010] In a fourth aspect, the present invention provides a coated substrate comprising at least one coating layer on at least a portion of at least one surface of the substrate, wherein the coating is formed from a polymer dispersion produced by the method of the present invention, or from a composition comprising the polymer dispersion of the present invention and optionally additional agents.

[0011] In a fifth aspect, the present invention provides a method for producing a multilayer coated substrate, the method being: A step of applying a pre-coat composition to at least a portion of at least one surface of a substrate to form a first coating, The present invention includes the step of applying a polymer dispersion produced by the method of the present invention, or a composition comprising the polymer dispersion of the present invention and optionally additional agents, to a first coating to form a second coating.

[0012] In a sixth aspect, the present invention provides a multilayer coated substrate having at least two coatings, the at least two coatings being A first coating on at least a portion of at least one surface of the substrate, The present invention comprises a first coating on which a polymer dispersion produced by the method of the present invention is applied, or a second coating comprising a composition containing the polymer dispersion of the present invention and optionally additional agents.

[0013] In a seventh aspect, the present invention provides a packaging material comprising a multilayer coated substrate according to the present invention.

[0014] The present invention provides a polymer dispersion that can be prepared by polymerization, incorporated into a composition, and constructed into (one or more) coating layers to provide optimal barrier performance. The present invention also provides the use of bio-based waxes to increase the bio-content of the product and improve barrier properties.

[0015] The waxes in the polymer dispersion, the first wax and the second wax, are plant waxes, plant-based waxes, animal waxes, or animal-based waxes. In one embodiment, the polymer dispersion is substantially free of fossil fuel-derived waxes such as petroleum wax and polyethylene wax, and preferably free of fossil fuel-derived waxes. Generally, waxes are a group of certain organic substances with a melting point below 100°C that melt without decomposing. Waxes can naturally exist on the surface of plants and tend to crystallize to exhibit good oil absorption properties. These naturally occurring waxes may consist of fatty acids, alcohols, amides, esters, ketones, aldehydes, aromatic structures, carboxylic acids, or mixtures thereof. Biowaxes can be produced by modifying triglycerides in vegetable oils from various sources. Biowaxes can be produced by hydrogenation, esterification, transesterification, chemical substitution, and transesterification reactions. The most definitive properties of biowaxes are their melting point and freezing point.

[0016] In one embodiment, the polymer dispersion substantially does not contain styrene and preferably does not contain styrene.

[0017] Surprisingly, by using a polymer dispersion formed by polymerizing an acrylate monomer in the presence of a wax and a composition optionally containing additional agents, the water and moisture resistance of the coating (i.e., barrier performance) is improved compared to a polymer dispersion containing only a polymer formed by polymerizing the same acrylate monomer.

[0018] Even more surprisingly, by using a polymer dispersion formed by polymerizing an acrylate monomer and subsequently adding a wax to the formed polymer material and a coating optionally containing additional agents, even better barrier properties (water and moisture resistance) can be obtained.

[0019] Also, without being bound by any theory, it is considered that the barrier properties (water and moisture resistance) are improved by a polymer dispersion formed by polymerizing an acrylate monomer in the presence of a first wax to produce a polymer material and subsequently adding a second wax to the polymer material and a coating optionally containing additional agents.

[0020] Also, without being bound by any theory, it is considered that the barrier properties (water and moisture resistance) are improved by a polymer dispersion formed by polymerizing an acrylate monomer in the presence of a first wax and a second wax to produce a polymer material and a coating optionally containing additional agents.

[0021] Even more surprisingly, a multilayer-coated substrate having two coating layers including a first coating having grease resistance and a second coating including the polymer dispersion of the present invention and optionally additional agents on the first coating has been found to have both grease resistance and water and moisture resistance.

[0022] The appended claims define the scope of protection.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Detailed Description In a first aspect, the present invention provides a method for producing a polymer dispersion, the method comprising: (a) polymerizing an acrylate monomer in the presence of a wax to produce a polymer dispersion; (b) polymerizing an acrylate monomer to produce a polymer material and introducing a wax into the polymer material to produce a polymer dispersion; (c) polymerizing an acrylate monomer in the presence of a first wax to produce a polymer material and introducing a second wax into the polymer material to produce a polymer dispersion; (d) polymerizing an acrylate monomer in the presence of a first wax and a second wax to produce a polymer dispersion; or (e) polymerizing an acrylate monomer in the presence of a first wax to produce a polymer material (A), polymerizing an acrylate monomer in the presence of a second wax to produce a polymer material (B), and mixing the polymer material (A) and the polymer material (B) to produce a polymer dispersion.

[0024] In option (a), a polymer dispersion is produced by polymerizing an acrylate monomer in the presence of a wax. In this method, the acrylate monomer and the wax are placed in the same container and the acrylate monomer is polymerized in the presence of the wax. The monomer can be supplied to the wax-containing composition for polymerization or the wax can be supplied to the polymerization mixture during polymerization.

[0025] Option (b) involves polymerizing an acrylate monomer, followed by introducing wax into the resulting polymer material. In this method, the wax is introduced (added) to the polymer material. In one embodiment, the polymer material and the wax are mixed to produce a polymer dispersion. The mixing can be applied over a predetermined period of time. The mixing can be carried out by any suitable method known in the art.

[0026] In option (c), an acrylate monomer is polymerized in the presence of a first wax to produce a polymer material, followed by the introduction of a second wax into the polymer material. In one embodiment, the polymer material and the second wax are mixed to produce a polymer dispersion. The mixing can be applied over a predetermined period of time. The mixing can be carried out by any suitable method known in the art. The monomer can be supplied to the wax-containing composition for polymerization, or the wax can be supplied to the polymerization mixture during polymerization.

[0027] Option (d) involves polymerizing an acrylate monomer in the presence of a first wax and a second wax to produce a polymer dispersion. In this method, the acrylate monomer and the first and second waxes are placed in the same container, and the polymerization of the acrylate monomer is carried out in the presence of the first and second waxes. The monomer can be supplied to the wax-containing composition for polymerization, or the wax can be supplied to the polymerization mixture during polymerization.

[0028] Option (e) involves polymerizing an acrylate monomer in the presence of a first wax to produce polymer material (A), polymerizing an acrylate monomer in the presence of a second wax to produce polymer material (B), and mixing polymer material (A) and polymer material (B) to produce a polymer dispersion. The monomer can be supplied to the wax-containing composition for polymerization, or the wax can be supplied to the polymerization mixture during polymerization.

[0029] The first wax and the second wax may be the same or different. In one embodiment, the first wax and the second wax are the same. In one embodiment, the first wax and the second wax are different.

[0030] In one embodiment, the total amount of wax in option (a) is 0.1 to 45% by weight, preferably 0.5 to 25% by weight, more preferably 1 to 15% by weight, and most preferably 1.5 to 9.9% by weight, based on the total weight of the polymer dispersion.

[0031] In one embodiment, the total amount of wax in option (b) is 0.1 to 45% by weight, preferably 0.5 to 25% by weight, more preferably 1 to 15% by weight, and most preferably 1.5 to 9.9% by weight, based on the total weight of the polymer dispersion.

[0032] In one embodiment, the total amount of the first wax and the second wax in option (c) is 0.1 to 45% by weight, preferably 0.5 to 25% by weight, more preferably 1 to 15% by weight, and most preferably 1.5 to 9.9% by weight, based on the total weight of the polymer dispersion.

[0033] In one embodiment, the total amount of the first wax and the second wax in option (d) is 0.1 to 45% by weight, preferably 0.5 to 25% by weight, more preferably 1 to 15% by weight, and most preferably 1.5 to 9.9% by weight, based on the total weight of the polymer dispersion.

[0034] In one embodiment, the total amount of the first wax and the second wax in option (e) is 0.1 to 45% by weight, preferably 0.5 to 25% by weight, more preferably 1 to 15% by weight, and most preferably 1.5 to 9.9% by weight, based on the total weight of the polymer dispersion.

[0035] In one embodiment, the wax, the first wax, and the second wax have melting points of 30°C to 90°C, preferably 35°C to 65°C, and more preferably 40°C to 55°C.

[0036] In one embodiment, the wax, the first wax, and the second wax have different melting points. The difference in melting points between the first wax and the second wax is 0 to 60°C, preferably 5 to 55°C, and more preferably 20 to 50°C.

[0037] In one embodiment, the wax, the first wax and the second wax are a plant wax, a plant-based wax, an animal wax, or an animal-based wax, and preferably the plant wax of the wax, the first wax and the second wax contains fatty acids, alcohols, amides, esters, ketones, aldehydes, aromatic structures, carboxylic acids, or mixtures thereof.

[0038] In one embodiment, the wax, first wax and second wax are plant wax, plant-based wax, animal wax, or animal-based wax, preferably the wax is a plant wax or plant-based wax, more preferably the wax is a plant-based wax, and even more preferably the wax is selected from palm oil-based wax, coconut oil-based wax, candelilla wax, carnauba wax, rice bran wax, soybean wax, sugarcane wax, sunflower wax, canola wax, rapeseed wax, or mixtures thereof, most preferably selected from palm oil-based wax, coconut oil-based wax, or mixtures thereof.

[0039] In one embodiment, the wax, the first wax and the second wax are a plant wax, a plant-based wax, an animal wax, or an animal-based wax, and preferably the plant wax of the wax, the first wax and the second wax contains fatty acids, alcohols, amides, esters, ketones, aldehydes, aromatic structures, carboxylic acids, or mixtures thereof.

[0040] In one embodiment, the wax, the first wax, and the second wax are natural waxes, preferably stable natural waxes containing a crystalline phase, more preferably waxes containing a triclinic or orthorhombic crystalline phase, and most preferably waxes containing an orthorhombic phase.

[0041] In one embodiment, the wax, the first wax and / or the second wax have undergone one or more melting and solidification cycles.

[0042] The wax, the first wax, and the second wax may be in any form.

[0043] In one embodiment, the wax, the first wax and / or the second wax are in solid form. The wax is in solid form when it exists at a temperature lower than its own melting point.

[0044] In one embodiment, the wax, the first wax and / or the second wax are in liquid form. The wax is in liquid form if it exists at a temperature higher than its own melting point.

[0045] In one embodiment, the wax, the first wax and / or the second wax is a wax dispersion, preferably an aqueous wax dispersion.

[0046] If the wax is in solid form, it is preferable to first prepare a wax dispersion before introducing the wax components into the method.

[0047] Aqueous wax dispersions can be produced in various ways. It is preferable to produce a stable wax dispersion, meaning that phase separation should not occur or the aqueous wax dispersion is redispersible. Typically, an aqueous stabilizer solution is used to stabilize the wax dispersion. When preparing the wax dispersion, the selected wax is melted and mixed with a stabilizer using a blender or mixer such as an Ultraturrax, and then passed through a homogenizer under high pressure to form the aqueous wax dispersion. The stabilizer may be an electrostatic stabilizer, an electrostatic steric stabilizer, a steric stabilizer, or a combination thereof. The stabilizer in the stabilizer solution may be anionic, cationic, or nonionic. Preferably, the stabilizer is anionic or nonionic, and more preferably, nonionic. The solids content of the aqueous wax dispersion may be 10-50% by weight. The volume-based particle size D50 of the aqueous dispersion is preferably 100-1500 nm, as measured with a Malvern Mastersizer 3000.

[0048] In one embodiment, the polymer dispersion is a nonionic or anionic aqueous polymer dispersion, preferably an anionic aqueous polymer dispersion.

[0049] In one embodiment, the acrylate monomer comprises a vinyl monomer, preferably the vinyl monomer comprises at least one first monomer (a) selected from either C1-C8 alkyl (meth)acrylates or mixtures thereof, at least one second monomer (b) selected from either vinyl monomers or mixtures thereof that optionally contain aromatic structures, and / or at least one monomer (c) optionally comprising other vinyl monomers.

[0050] At least one monomer (c) comprises at least one first monomer (a) and at least one monomer (b) that is different from vinyl monomer.

[0051] In one embodiment, the acrylate monomer comprises at least one monomer (a), at least one monomer (b), and at least one monomer (c).

[0052] In one embodiment, the acrylate monomer comprises at least one monomer (a) and at least one monomer (b).

[0053] In one embodiment, the acrylate monomer comprises at least one monomer (a) and at least one monomer (c).

[0054] In one embodiment, the vinyl monomer may comprise at least one first monomer (a) selected from any of the alkyl (meth)acrylates, such as C1-C8 alkyl (meth)acrylates, and mixtures thereof. A suitable first monomer (a) may be, for example, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-propyl or isopropyl acrylate and the corresponding propyl methacrylate, n-butyl, iso-butyl, tert-butyl or 2-butyl acrylate and the corresponding butyl methacrylate, n-pentyl or neopentyl acrylate and the corresponding pentyl methacrylate, 2-hexyl or 2-ethylhexyl acrylate and the corresponding methacrylate, n-octyl or isooctyl acrylate and the corresponding methacrylate. For example, the first monomer (a) may be a mixture of n-butyl acrylate, methyl methacrylate, 2-ethylhexyl acrylate, or isobutyl methacrylate.

[0055] In one embodiment, the first monomer (a) is selected from any of the following: C1-C6 alkyl acrylates, C1-C6 alkyl methacrylates, or mixtures thereof, for example, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl, isobutyl, tert-butyl or 2-butyl acrylate and the corresponding butyl methacrylate, n-hexyl, isohexyl or 2-hexyl acrylate and the corresponding methacrylate. For example, the first monomer (a) may be a mixture of n-butyl acrylate, methyl methacrylate, n-hexyl acrylate or isobutyl methacrylate.

[0056] In one embodiment, the vinyl monomer may comprise at least one second monomer (b) selected from aromatic vinyl monomers such as styrene, α-methylstyrene, vinyltoluene, ethylvinyltoluene, divinylbenzene, vinylphenol, and mixtures thereof.

[0057] The polymer material can be obtained by radical polymerization of a first monomer (a) in an amount of 25-100% by weight, preferably 30-100% by weight, more preferably 45-99.9% by weight, and a second monomer (b) in an amount of 0-75% by weight, preferably 0-70% by weight, more preferably 0-55% by weight, calculated from the total dry solids content of monomers (a) and (b).

[0058] In one embodiment, the polymer material may be obtained by radical polymerization of at least a first monomer (a), at least one second monomer (b), and at least one third monomer (c), wherein the at least one third monomer is ethylenically unsaturated and different from the at least one first monomer (a) and the at least one second monomer (b). Suitable ethylenically unsaturated third monomers (c) are stearyl acrylate, stearyl methacrylate, esters of acrylic acid and methacrylic acid with alcohols having more than eight carbon atoms, and further anionic comonomers such as acrylonitrile, methacrylonitrile, acrylamide, vinyl acetate, or acrylic acid and methacrylic acid. Acrylic acid and methacrylic acid may be preferred as the third monomer (c). The amount of the third monomer (c) may be 0 to 9% by weight, preferably 0 to 7% by weight, more preferably 0.1 to 5% by weight, calculated from the total dry solids content of monomers (a) + (b) + (c).

[0059] In one embodiment, the polymer material may have at least one glass transition temperature Tg in the range of -30°C to +95°C, preferably -25°C to +80°C, more preferably -20°C to +40°C, and even more preferably -14°C to +20°C. The polymer material does not have to have a distinct glass transition temperature. The glass transition temperature is measured from a lyophilized sample using a differential scanning calorimeter Mettler Toledo DSC 3+.

[0060] In one embodiment, polymerization of the polymer material is carried out in the presence of a free radical initiator. Suitable free radical initiators include azo initiators such as 2,2'-azobis(2-methylpropionitrile), 2,2'-azobis(2-methylbutyronitrile), or dimethyl-2,2'-azobis(2-methylpropionate), peroxides such as hydrogen peroxide, sodium peroxodisulfate, potassium peroxodisulfate, ammonium peroxodisulfate, dibenzoyl peroxide, dilauroyl peroxide, di-tert-butyl peroxide, tert-butyl hydroperoxide, or mixtures thereof. In one preferred embodiment, the initiator is sodium peroxodisulfate, potassium peroxodisulfate, ammonium peroxodisulfate, or a mixture thereof.

[0061] In one embodiment, polymerization of the polymer material is carried out in the presence of at least one additive, for example, a stabilizer for the dispersion, such as a surfactant, preferably an anionic or nonionic surfactant. The polymerization of the polymer material may also include additional steps such as the addition of an antifoaming agent, pH adjustment, and post-treatment of residual monomers during or after polymerization. The polymer material may be filtered after polymerization. In one embodiment, the at least one additive includes a stabilizer, a surfactant such as an anionic or nonionic surfactant, an antifoaming agent, a pH adjuster, an initiator, or a mixture thereof. The at least one additive may be the same as the additives described later herein.

[0062] In one embodiment, a polymer dispersion comprising an acrylate polymer and a wax, or an acrylate polymer, a first wax and a second wax, and optionally at least one additive, preferably at least one additive, has a solids content of at least 20% by weight, preferably at least 30% by weight, and possibly at least 40% by weight. In one embodiment, the solids content of the polymer dispersion may be in the range of 20 to 60% by weight, preferably 30 to 59% by weight, and more preferably 40 to 55% by weight.

[0063] In one embodiment, a polymer dispersion comprising an acrylate polymer and a wax, or an acrylate polymer, a first wax and a second wax, and optionally at least one additive, preferably at least one additive, has a viscosity of ≤1500 mPa·s, preferably ≤800 mPa·s, more preferably ≤400 mPa·s. The viscosity may also be in the range of 1 to 1500 mPa·s, preferably 1 to 800 mPa·s, more preferably 2 to 500 mPa·s. All viscosity values ​​were measured at 25°C using a Brookfield LVDV viscometer in a small sample adapter with a spindle 18, and the solids content was measured at 40% by weight.

[0064] In one embodiment, the pH of a polymer dispersion containing an acrylate polymer and a wax, or an acrylate polymer, a first wax and a second wax, and optionally at least one additive, preferably at least one additive, is 3.0 to 9.5, preferably 5.5 to 9.0, and more preferably 7.0 to 8.5, when measured at 25°C.

[0065] In one embodiment, a polymer dispersion comprising an acrylate polymer and a wax, or an acrylate polymer, a first wax and a second wax, and optionally at least one additive, preferably at least one additive, has a particle size D50 in the range of, for example, 50 to 800 nm, preferably 60 to 500 nm, and more preferably 80 to 350 nm. The particle size D50 is measured by using a Zetasizer Nano ZS, Malvern. In relation to the present invention, the particle size D50 refers to the value relative to the 50th percentile of the volume-based distribution.

[0066] In one embodiment, an additional agent is introduced into the polymer dispersions produced by (a), (b), (c), (d), and (e).

[0067] The additional agents may be any suitable agents known in the art used in the manufacture of paper or cardboard.

[0068] In one embodiment, the additional agents include stabilizers, surfactants, dispersants, rheological modifiers, pigments, pH adjusters, defoamers, additional waxes, or mixtures thereof, preferably stabilizers, surfactants, dispersants, or mixtures thereof, more preferably surfactants.

[0069] In one embodiment, the surfactant has an anionic functional group at its head, such as sulfates, sulfonates, phosphates, and carboxylates; major alkyl sulfates such as ammonium lauryl sulfate, sodium lauryl sulfate (SLS), and potassium lauryl sulfate; related alkyl ether sulfates such as sodium laureth sulfate, sodium lauryl ether sulfate (SLES), and sodium myreth sulfate; sulfosuccinate esters such as sodium dioctyl sulfosuccinate; carboxylates such as carboxylates (soaps), for example, sodium stearate; and pH-dependent primary, secondary, or tertiary surfactants. The materials include cationic surfactants such as amines, octenidine dihydrochloride, or permanently charged quaternary ammonium salts such as cetrimonium bromide (CTAB), cetylpyridinium chloride (CPC), benzalkonium chloride (BAC), benzethonium chloride (BZT), dimethyldioctadecylammonium chloride, and dioctadecyldimethylammonium bromide (DODAB); and nonionic surfactants such as polyglycol ethers, aliphatic alcohol polyglycol ethers such as polyethylene glycol dioleate and polysorbate, or derivatives thereof and mixtures thereof.

[0070] In one embodiment, the stabilizer includes additional polymer stabilizers such as water-soluble polysaccharides, for example, anionic starch, carboxymethylcellulose, or other water-soluble polymers, for example, polyvinyl alcohol, or mixtures thereof.

[0071] In one embodiment, the dispersant includes anionic polymers such as homopolymers and copolymers of acrylic acid, methacrylic acid, and maleic acid, as well as their salts or mixtures thereof.

[0072] In one embodiment, the rheological modifier includes an anionic polyacrylamide polymer, an anionic acrylate polymer, (one or more) ionic hydrophobic polyethers, polyvinyl alcohol, carboxymethylcellulose, hydroxyethylcellulose, starch, protein derivatives, (one or more) alkali-swellable polyacrylates, nonionic associated (HEUR / HMPE), anionic associated (HASE), and non-associative (ASE) thickener (ASE) compounds, or mixtures thereof.

[0073] In one embodiment, the pigment comprises kaolin, calcium carbonate, talc, or a mixture thereof.

[0074] In one embodiment, the pH adjuster comprises NaOH, KOH, ammonium hydroxide, or a mixture thereof, preferably KOH, ammonium hydroxide, or a mixture thereof.

[0075] In one embodiment, the defoaming agent includes an oil-based defoaming agent, a powder defoaming agent, a silicone-based defoaming agent, a polymer defoaming agent (EO / PO-based defoaming agent), an alkyl polyacrylate, or a mixture thereof.

[0076] In one preferred embodiment, the polymer dispersion does not contain any intentionally added fluorine compounds.

[0077] In one embodiment, the polymer dispersion does not contain a silicone compound except for an amount added for defoaming purposes. The amount of the silicone compound for defoaming purposes may be less than 0.1% by weight, more preferably less than 0.01% by weight.

[0078] In a second aspect, the present invention is (a) A step of polymerizing an acrylate monomer in the presence of wax to produce a polymer dispersion; (b) A step of polymerizing acrylate monomers to produce a polymer material, and introducing wax into the polymer material to produce a polymer dispersion; (c) A step of polymerizing an acrylate monomer in the presence of a first wax to produce a polymer material, and introducing a second wax into the polymer material to produce a polymer dispersion; (d) A step of polymerizing acrylate monomers in the presence of a first wax and a second wax to produce a polymer dispersion; or (e) A polymer dispersion is provided, formed by the steps of (e) polymerizing an acrylate monomer in the presence of a first wax to produce a polymer material (A), polymerizing an acrylate monomer in the presence of a second wax to produce a polymer material (B), and mixing polymer material (A) and polymer material (B) to produce a polymer dispersion.

[0079] Option (a) produces a polymer dispersion by polymerizing an acrylate monomer in the presence of wax. In this method, the acrylate monomer and wax are placed in the same container, and the polymerization of the acrylate monomer is carried out in the presence of wax. The monomer can be supplied to the wax-containing composition for polymerization, or the wax can be supplied to the polymerization mixture during polymerization.

[0080] Option (b) involves polymerizing an acrylate monomer, followed by introducing wax into the resulting polymer material. In this method, the wax is introduced (added) to the polymer material. In one embodiment, the polymer material and the wax are mixed to produce a polymer dispersion. The mixing can be applied over a predetermined period of time. The mixing can be carried out by any suitable method known in the art.

[0081] In option (c), an acrylate monomer is polymerized in the presence of a first wax to produce a polymer material, followed by the introduction of a second wax into the polymer material. In one embodiment, the polymer material and the second wax are mixed to produce a polymer dispersion. The mixing can be applied over a predetermined period of time. The mixing can be carried out by any suitable method known in the art.

[0082] Option (d) involves polymerizing an acrylate monomer in the presence of a first wax and a second wax to produce a polymer dispersion. In this method, the acrylate monomer and the first and second waxes are placed in the same container, and the polymerization of the acrylate monomer is carried out in the presence of the first and second waxes. The monomer can be supplied to the wax-containing composition for polymerization, or the wax can be supplied to the polymerization mixture during polymerization.

[0083] Option (e) involves polymerizing an acrylate monomer in the presence of a first wax to produce polymer material (A), polymerizing an acrylate monomer in the presence of a second wax to produce polymer material (B), and mixing polymer material (A) and polymer material (B) to produce a polymer dispersion. The monomer can be supplied to the wax-containing composition for polymerization, or the wax can be supplied to the polymerization mixture during polymerization.

[0084] The first wax and the second wax may be the same or different. In one embodiment, the first wax and the second wax are the same. In one embodiment, the first wax and the second wax are different.

[0085] In one embodiment, the total amount of wax in option (a) is 0.1 to 45% by weight, preferably 0.5 to 25% by weight, more preferably 1 to 15% by weight, and most preferably 1.5 to 9.9% by weight, based on the total weight of the polymer dispersion.

[0086] In one embodiment, the total amount of wax in option (b) is 0.1 to 45% by weight, preferably 0.5 to 25% by weight, more preferably 1 to 15% by weight, and most preferably 1.5 to 9.9% by weight, based on the total weight of the polymer dispersion.

[0087] In one embodiment, the total amount of the first wax and the second wax in option (c) is 0.1 to 45% by weight, preferably 0.5 to 25% by weight, more preferably 1 to 15% by weight, and most preferably 1.5 to 9.9% by weight, based on the total weight of the polymer dispersion.

[0088] In one embodiment, the total amount of the first wax and the second wax in option (d) is 0.1 to 45% by weight, preferably 0.5 to 25% by weight, more preferably 1 to 15% by weight, and most preferably 1.5 to 9.9% by weight, based on the total weight of the polymer dispersion.

[0089] In one embodiment, the total amount of the first wax and the second wax in option (e) is 0.1 to 45% by weight, preferably 0.5 to 25% by weight, more preferably 1 to 15% by weight, and most preferably 1.5 to 9.9% by weight, based on the total weight of the polymer dispersion.

[0090] In one embodiment, the wax, the first wax, and the second wax have melting points of 30°C to 90°C, preferably 35°C to 65°C, and more preferably 40°C to 55°C.

[0091] In one embodiment, the wax, the first wax, and the second wax have different melting points. The difference in melting points between the first wax and the second wax is 0 to 60°C, preferably 5 to 55°C, and more preferably 20 to 50°C.

[0092] In one embodiment, the wax, first wax and second wax are plant wax, plant-based wax, animal wax, or animal-based wax, preferably the wax is a plant wax or plant-based wax, more preferably the wax is a plant-based wax, and even more preferably the wax is selected from palm oil-based wax, coconut oil-based wax, candelilla wax, carnauba wax, rice bran wax, soybean wax, sugarcane wax, sunflower wax, canola wax, rapeseed wax, or mixtures thereof, most preferably selected from palm oil-based wax, coconut oil-based wax, or mixtures thereof.

[0093] In one embodiment, the wax, the first wax, and the second wax are natural waxes, preferably stable natural waxes containing a crystalline phase, more preferably waxes containing a triclinic or orthorhombic crystalline phase, and most preferably waxes containing an orthorhombic phase.

[0094] In one embodiment, the wax, the first wax and / or the second wax have undergone one or more melting and solidification cycles.

[0095] The wax, the first wax, and the second wax may be in any form.

[0096] In one embodiment, the wax, the first wax and / or the second wax are in solid form. The wax is in solid form when it exists at a temperature lower than its own melting point.

[0097] In one embodiment, the wax, the first wax and / or the second wax are in liquid form. The wax is in liquid form if it exists at a temperature higher than its own melting point.

[0098] In one embodiment, the wax, the first wax and / or the second wax is a wax dispersion, preferably an aqueous wax dispersion.

[0099] If the wax is in solid form, it is preferable to first prepare a wax dispersion before introducing the wax components into the method.

[0100] Aqueous wax dispersions can be produced in various ways. It is preferable to produce a stable wax dispersion, meaning that phase separation should not occur or the aqueous wax dispersion is redispersible. Typically, an aqueous stabilizer solution is used to stabilize the wax dispersion. When preparing the wax dispersion, the selected wax is melted and mixed with a stabilizer using a kitchen blender or a mixer such as an Ultraturrax, and then passed through a homogenizer under high pressure to form the aqueous wax dispersion. The stabilizer may be an electrostatic stabilizer, an electrostatic steric stabilizer, a steric stabilizer, or a combination thereof. The stabilizer in the stabilizer solution may be anionic, cationic, or nonionic. Preferably, the stabilizer is anionic or nonionic, and more preferably, nonionic. The solids content of the aqueous wax dispersion may be 10-50% by weight. The volume-based particle size D50 of the aqueous dispersion is preferably 100-1500 nm, as measured with a Malvern Mastersizer 3000.

[0101] In one embodiment, the polymer dispersion is an aqueous polymer dispersion, preferably an anionic aqueous polymer dispersion.

[0102] In one embodiment, the acrylate monomer comprises a vinyl monomer, preferably the vinyl monomer comprises at least one first monomer (a) selected from either C1-C8 alkyl (meth)acrylates or mixtures thereof, at least one second monomer (b) selected from either vinyl monomers or mixtures thereof that optionally contain aromatic structures, and / or at least one monomer (c) optionally comprising other vinyl monomers.

[0103] At least one monomer (c) comprises at least one first monomer (a) and at least one monomer (b) that is different from vinyl monomer.

[0104] In one embodiment, the acrylate monomer comprises at least one monomer (a), at least one monomer (b), and at least one monomer (c).

[0105] In one embodiment, the acrylate monomer comprises at least one monomer (a) and at least one monomer (b).

[0106] In one embodiment, the acrylate monomer comprises at least one monomer (a) and at least one monomer (c).

[0107] In one embodiment, the vinyl monomer may comprise at least one first monomer (a) selected from any of the alkyl (meth)acrylates, such as C1-C8 alkyl (meth)acrylates, and mixtures thereof. A suitable first monomer (a) may be, for example, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-propyl or isopropyl acrylate and the corresponding propyl methacrylate, n-butyl, iso-butyl, tert-butyl or 2-butyl acrylate and the corresponding butyl methacrylate, n-pentyl or neopentyl acrylate and the corresponding pentyl methacrylate, 2-hexyl or 2-ethylhexyl acrylate and the corresponding methacrylate, n-octyl or isooctyl acrylate and the corresponding methacrylate. For example, the first monomer (a) may be a mixture of n-butyl acrylate, methyl methacrylate, 2-ethylhexyl acrylate, or isobutyl methacrylate.

[0108] In one embodiment, the first monomer (a) is selected from any of the following: C1-C6 alkyl acrylates, C1-C6 alkyl methacrylates, or mixtures thereof, for example, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl, isobutyl, tert-butyl or 2-butyl acrylate and the corresponding butyl methacrylate, n-hexyl, isohexyl or 2-hexyl acrylate and the corresponding methacrylate. For example, the first monomer (a) may be a mixture of n-butyl acrylate, methyl methacrylate, n-hexyl acrylate or isobutyl methacrylate.

[0109] In one embodiment, the vinyl monomer may comprise at least one second monomer (b) selected from aromatic vinyl monomers such as styrene, α-methylstyrene, vinyltoluene, ethylvinyltoluene, divinylbenzene, vinylphenol, and mixtures thereof.

[0110] The polymer material can be obtained by radical polymerization of a first monomer (a) in an amount of 25-100% by weight, preferably 30-100% by weight, more preferably 45-99.9% by weight, and a second monomer (b) in an amount of 0-75% by weight, preferably 0-70% by weight, more preferably 0-55% by weight, calculated from the total dry solids content of monomers (a) and (b).

[0111] In one embodiment, the polymer material may be obtained by radical polymerization of at least a first monomer (a), at least one second monomer (b), and at least one third monomer (c), wherein the at least one third monomer is ethylenically unsaturated and different from the at least one first monomer (a) and the at least one second monomer (b). Suitable ethylenically unsaturated third monomers (c) are stearyl acrylate, stearyl methacrylate, esters of acrylic acid and methacrylic acid with alcohols having more than eight carbon atoms, and further anionic comonomers such as acrylonitrile, methacrylonitrile, acrylamide, vinyl acetate, or acrylic acid and methacrylic acid. Acrylic acid and methacrylic acid may be preferred as the third monomer (c). The amount of the third monomer (c) may be 0 to 9% by weight, preferably 0 to 7% by weight, more preferably 0.1 to 5% by weight, calculated from the total dry solids content of monomers (a) + (b) + (c).

[0112] In one embodiment, the polymer material may have at least one glass transition temperature Tg in the range of -30°C to +95°C, preferably -25°C to +80°C, more preferably -20°C to +40°C, and even more preferably -14°C to +20°C. The polymer dispersion does not need to have a distinct glass transition temperature.

[0113] Polymerization of polymer materials can be carried out in the presence of a free radical initiator. Suitable free radical initiators may be azo initiators such as 2,2'-azobis(2-methylpropionitrile), 2,2'-azobis(2-methylbutyronitrile), or dimethyl-2,2'-azobis(2-methylpropionate), or peroxides such as hydrogen peroxide, sodium peroxodisulfate, potassium peroxodisulfate, ammonium peroxodisulfate, dibenzoyl peroxide, dilauroyl peroxide, di-tert-butyl peroxide, or tert-butyl hydroperoxide. In one preferred embodiment, the initiator may be sodium peroxodisulfate, potassium peroxodisulfate, ammonium peroxodisulfate, or a mixture thereof.

[0114] In one embodiment, polymerization of the polymer material is carried out in the presence of at least one additive, for example, a stabilizer for the dispersion, such as a surfactant, preferably an anionic or nonionic surfactant. The polymerization of the polymer material may also include additional steps such as the addition of an antifoaming agent, pH adjustment, and post-treatment of residual monomers during or after polymerization. The polymer material may be filtered after polymerization. In one embodiment, the at least one additive includes a stabilizer, a surfactant such as an anionic or nonionic surfactant, an antifoaming agent, a pH adjuster, an initiator, or a mixture thereof. The at least one additive may be the same as the additives described later herein.

[0115] In one embodiment, a polymer dispersion comprising an acrylate polymer and a wax, or an acrylate polymer, a first wax and a second wax, and optionally at least one additive, preferably at least one additive, has a solids content of at least 20% by weight, preferably at least 30% by weight, and possibly at least 40% by weight. In one embodiment, the solids content of the polymer dispersion may be in the range of 20 to 60% by weight, preferably 30 to 59% by weight, and more preferably 40 to 55% by weight.

[0116] In one embodiment, a polymer dispersion comprising an acrylate polymer and a wax, or an acrylate polymer, a first wax and a second wax, and optionally at least one additive, preferably at least one additive, has a viscosity of ≤1500 mPa·s, preferably ≤800 mPa·s, more preferably ≤400 mPa·s. The viscosity may also be in the range of 1 to 1500 mPa·s, preferably 1 to 800 mPa·s, more preferably 2 to 500 mPa·s. All viscosity values ​​were measured at 25°C using a Brookfield LVDV viscometer in a small sample adapter with a spindle 18, and the solids content was measured at 40% by weight.

[0117] In one embodiment, the pH of a polymer dispersion containing an acrylate polymer and a wax, or an acrylate polymer, a first wax and a second wax, and optionally at least one additive, preferably at least one additive, is 3.0 to 9.5, preferably 5.5 to 9.0, and more preferably 7.0 to 8.5, when measured at 25°C.

[0118] In one embodiment, a polymer dispersion comprising an acrylate polymer and a wax, or an acrylate polymer, a first wax and a second wax, and optionally at least one additive, preferably at least one additive, has a particle size D50 in the range of, for example, 50 to 800 nm, preferably 60 to 500 nm, and more preferably 80 to 350 nm. The particle size D50 is measured by using a Zetasizer Nano ZS, Malvern. In relation to the present invention, the particle size D50 refers to the value relative to the 50th percentile of the volume-based distribution.

[0119] In one embodiment, the polymer dispersions of (a), (b), (c), and (e) contain additional agents.

[0120] The additional agents may be any suitable agents known in the art used in the manufacture of paper or cardboard.

[0121] In one embodiment, the additional agents include stabilizers, surfactants, dispersants, rheological modifiers, pigments, pH adjusters, defoamers, additional waxes, or mixtures thereof, preferably stabilizers, surfactants, dispersants, or mixtures thereof, more preferably surfactants.

[0122] In one embodiment, the surfactant has an anionic functional group at its head, such as sulfates, sulfonates, phosphates, and carboxylates; major alkyl sulfates such as ammonium lauryl sulfate, sodium lauryl sulfate (SLS), and potassium lauryl sulfate; related alkyl ether sulfates such as sodium laureth sulfate, sodium lauryl ether sulfate (SLES), and sodium myreth sulfate; sulfosuccinate esters such as sodium dioctyl sulfosuccinate; carboxylates such as carboxylates (soaps), for example, sodium stearate; and pH-dependent primary, secondary, or tertiary surfactants. The materials include cationic surfactants such as amines, octenidine dihydrochloride, or permanently charged quaternary ammonium salts such as cetrimonium bromide (CTAB), cetylpyridinium chloride (CPC), benzalkonium chloride (BAC), benzethonium chloride (BZT), dimethyldioctadecylammonium chloride, and dioctadecyldimethylammonium bromide (DODAB); and nonionic surfactants such as polyglycol ethers, aliphatic alcohol polyglycol ethers such as polyethylene glycol dioleate and polysorbate, or derivatives thereof and mixtures thereof.

[0123] In one embodiment, the stabilizer includes additional polymer stabilizers such as water-soluble polysaccharides, for example, anionic starch, carboxymethylcellulose, or other water-soluble polymers, for example, polyvinyl alcohol, or mixtures thereof.

[0124] In one embodiment, the dispersant includes anionic polymers such as homopolymers and copolymers of acrylic acid, methacrylic acid, and maleic acid, as well as their salts or mixtures thereof.

[0125] In one embodiment, the rheological modifier includes an anionic polyacrylamide polymer, an anionic acrylate polymer, (one or more) ionic hydrophobic polyethers, polyvinyl alcohol, carboxymethylcellulose, hydroxyethylcellulose, starch, protein derivatives, (one or more) alkali-swellable polyacrylates, nonionic associated (HEUR / HMPE), anionic associated (HASE), and non-associative (ASE) thickener (ASE) compounds, or mixtures thereof.

[0126] In one embodiment, the pigment comprises kaolin, calcium carbonate, talc, or a mixture thereof.

[0127] In one embodiment, the pH adjuster includes NaOH, KOH, ammonium hydroxide, or a mixture thereof.

[0128] In one embodiment, the defoaming agent includes an oil-based defoaming agent, a powder defoaming agent, a silicone-based defoaming agent, a polymer defoaming agent (EO / PO-based defoaming agent), an alkyl polyacrylate, or a mixture thereof.

[0129] In one preferred embodiment, the polymer dispersion does not contain any intentionally added fluorine compounds.

[0130] In one embodiment, the polymer dispersion does not contain a silicone compound except for an amount added for defoaming purposes. The amount of the silicone compound for defoaming purposes may be less than 0.1% by weight, more preferably less than 0.01% by weight.

[0131] In one embodiment, the polymer dispersion is produced by the method of the present invention.

[0132] In a third aspect, the present invention provides the use of a polymer dispersion produced by the method according to the present invention, or a composition comprising the polymer dispersion of the present invention and optionally an additional agent for coating at least one layer on at least a portion of at least one surface of a substrate.

[0133] In one embodiment, the substrate is a fiber-based substrate.

[0134] In one embodiment, the composition includes additional agents.

[0135] The additional agents include stabilizers, surfactants, dispersants, rheological modifiers, pigments, pH adjusters, defoamers, additional waxes, or mixtures thereof, preferably including stabilizers, surfactants, dispersants, or mixtures thereof.

[0136] In one embodiment, the composition is used to coat at least one layer onto at least one surface of a substrate.

[0137] In one embodiment, the composition is used to coat at least two layers onto at least one identical surface of a substrate. In one embodiment, the at least two layers are identical.

[0138] In one embodiment, at least two layers are different. Each layer may have a different composition. One or more layers may not contain additional agents, or one or more layers may have different additional agents in different layers. By changing the additional agents in the composition used to coat one of the layers, the layers have different compositions.

[0139] In one embodiment, the polymer dispersion produced by the method of the present invention or the polymer dispersion of the present invention is used to coat one of at least two layers.

[0140] In one embodiment, a polymer dispersion produced by the method of the present invention, or a composition comprising the polymer dispersion of the present invention and an additional agent, is used to coat one of at least two layers.

[0141] Each of the at least two layers may be the same or different, and it is preferable that they be different.

[0142] In a fourth aspect, the present invention provides a coated substrate comprising at least one coating layer on at least a portion of at least one surface of the substrate, wherein the at least one coating layer is formed from a polymer dispersion produced using the method of the present invention, or from a composition comprising the polymer dispersion of the present invention and optionally additional agents.

[0143] In one embodiment, the substrate is a fiber-based substrate.

[0144] In one embodiment, the composition includes additional agents.

[0145] The additional agents include stabilizers, surfactants, dispersants, rheological modifiers, pigments, pH adjusters, defoamers, additional waxes, or mixtures thereof, preferably including stabilizers, surfactants, dispersants, or mixtures thereof.

[0146] In one embodiment, the coated substrate includes at least one layer on at least one surface of the substrate.

[0147] In one embodiment, the composition containing the polymer dispersion forms a coating layer having a polar component of surface energy of 0 to 30 mN / m, preferably 0.01 to 30, and more preferably 0.05 to 29 mN / m.

[0148] In one embodiment, the coated substrate includes at least two layers on at least one identical surface of the substrate.

[0149] In one embodiment, at least two layers are identical.

[0150] In one embodiment, at least two layers are different. Each layer may have a different composition. One or more layers may not contain additional agents, or one or more layers may have different additional agents in different layers. By changing the additional agents in one or more compositions, one or more coating layers may have different compositions.

[0151] In one embodiment, at least two layers that are in contact with each other have a difference in the polarity component of their surface energy of 3 to 30 mN / m, preferably 4 to 30 mN / m, and 6 to 29 mN / m.

[0152] In one embodiment, at least one of two coating layers is formed from a polymer dispersion produced by the method of the present invention or from the polymer dispersion of the present invention.

[0153] In one embodiment, at least one of two coating layers is formed from a polymer dispersion produced by the method of the present invention, or from a composition comprising the polymer dispersion of the present invention and additional agents.

[0154] Each of the at least two coating layers may be the same or different, and is preferably different.

[0155] In one embodiment, the total weight of one coating layer is 2-35 g / m². 2 Preferably 5-20 g / m 2 That is the case.

[0156] In a fifth aspect, the present invention provides a method for producing a multilayer coated substrate having at least two coatings, the method being: A step of applying a pre-coat composition to at least a portion of at least one surface of a substrate to form a first coating, The present invention includes the step of applying a polymer dispersion produced by the method of the present invention, or a composition comprising the polymer dispersion of the present invention and optionally additional agents, to a first coating to form a second coating.

[0157] In one embodiment, the substrate is a fiber-based substrate.

[0158] In one embodiment, the composition includes additional agents.

[0159] In one embodiment, the additional agents include stabilizers, surfactants, dispersants, rheological modifiers, pigments, pH adjusters, defoamers, additional waxes, or mixtures thereof, preferably including stabilizers, surfactants, dispersants, or mixtures thereof.

[0160] In one embodiment, the precoat composition is applied to at least one surface of a substrate to form a first coating, and the composition is applied on the first coating to form a second coating.

[0161] In one embodiment, the precoat composition is substantially wax-free, preferably wax-free.

[0162] In one embodiment, the precoat composition comprises at least one component selected from polymer dispersions or polymer solutions, stabilizers, surfactants, dispersants, rheological modifiers, pigments, pH adjusters, defoamers, waxes, or mixtures thereof. In one embodiment, the first coating may be a pigment-coated layer or a surface-size layer substantially containing starch.

[0163] In one embodiment, the pre-coat composition is substantially free of the polymer dispersion of the present invention, preferably free of the polymer dispersion of the present invention.

[0164] In one embodiment, the precoat composition forms a first coating on the substrate having a polar component with a surface energy of more than 8.5 mN / m.

[0165] In one embodiment, the precoat composition forms a first coating on the substrate having a polar component of surface energy of 6 to 30 mN / m, preferably 7 to 30, more preferably 8 to 29 mN / m.

[0166] In one embodiment, the total weight of the first coating is 2-35 g / m². 2 Preferably 5-20 g / m 2 That is the case.

[0167] In one embodiment, the total weight of the second coating is 2-35 g / m². 2 Preferably 5-20 g / m 2 That is the case.

[0168] In a sixth aspect, the present invention provides a multilayer coated substrate having at least two coatings, the at least two coatings being A first coating on at least a portion of at least one surface of the substrate, The present invention comprises a first coating on which a polymer dispersion produced by the method of the present invention is applied, or a second coating comprising a composition containing the polymer dispersion of the present invention and optionally additional agents.

[0169] In one embodiment, the composition includes additional agents.

[0170] In one embodiment, the additional agents include stabilizers, surfactants, dispersants, rheological modifiers, pigments, pH adjusters, defoamers, additional waxes, or mixtures thereof, preferably including stabilizers, surfactants, dispersants, or mixtures thereof.

[0171] In one embodiment, the first coating is on at least one surface of the substrate, and the second coating is on the first coating.

[0172] In one embodiment, the first coating is substantially wax-free, preferably wax-free.

[0173] In one embodiment, the first coating comprises at least one component selected from a polymer dispersion or solution, a stabilizer, a surfactant, a dispersant, a rheology modifier, a pigment, a pH adjuster, an antifoaming agent, a wax, or a mixture thereof. In one embodiment, the first coating can be a layer coated with a pigment or a surface sizing layer substantially containing starch.

[0174] In one embodiment, the first coating does not substantially contain the polymer dispersion of the present invention and preferably does not contain the polymer dispersion of the present invention.

[0175] In one embodiment, the first coating has a polar component of surface energy exceeding 8.5 mN / m.

[0176] In one embodiment, the first coating has a polar component of surface energy of 6 to 30 mN / m, preferably 7 to 30, more preferably 8 to 29 mN / m.

[0177] In one embodiment, the total weight of the first coating is 2 to 35 g / m 2 , preferably 5 to 20 g / m 2 .

[0178] In one embodiment, the total weight of the second coating is 2 to 35 g / m 2 , preferably 5 to 20 g / m 2 .

[0179] In a seventh aspect, the present invention provides a packaging material comprising the multi-layer coated substrate of the present invention.

[0180] In one embodiment, the substrate is a fiber-based substrate.

[0181] In one embodiment, the packaging material is a fiber-based material including a molded fiber-based article.

[0182] Preferably, the packaging material is for food packaging. [Examples]

[0183] Some embodiments of the present invention are illustrated in the following non-limiting examples.

[0184] Method for producing a polymer dispersion according to method (a) of the present invention Preparation of dispersion 1: 403 g of desalted water and 2.6 g of sodium dioctyl sulfosuccinate were mixed in a 1 L glass reactor equipped with a cooling / heating jacket under a nitrogen atmosphere. The pH was adjusted to 3.3 with citric acid. The mixture was heated to 90°C. Ammonium persulfate solution and monomers were supplied as starters. Monomers were supplied as a mixture: 345 g of a mixture consisting of 49 wt% 2-ethylhexyl acrylate, 47 wt% methyl methacrylate, and 4 wt% methacrylic acid was supplied for 120 minutes. 36.1 g of a 5.9% solution of ammonium persulfate was supplied for 180 minutes. 44.4 g of a 4.7% solution of ammonium hydroxide was supplied to the reactor for 70 minutes, starting 40 minutes after the start of monomer supply. After the supply of ammonium persulfate was terminated, 25 g of a 1.4% tert-butyl hydroperoxide solution was supplied to the reactor for 30 minutes to reduce residual monomers. Mixing was continued at 90°C for 90 minutes. The dispersion was cooled to room temperature and the pH was adjusted with a diluted ammonium hydroxide solution. Filtration was performed using a 100 μm filter cloth. A finely dispersed dispersion with a solid content of 41.1%, pH of 7.3, particle size D50 of 77 nm, and viscosity of 19 mPa·s was obtained.

[0185] Preparation of dispersion 2: The same dispersion as in dispersion 1, but with 10.3 g of palm oil-based wax added to a mixture of desalinated water and dioctyl sulfosuccinic acid in an aqueous dispersion with a solid content of 45% by weight. A finely dispersed dispersion was obtained with a solid content of 40.6%, a pH of 7.5, a particle size D50 of 207 nm, and a viscosity of 16 mPa·s.

[0186] Preparation of dispersion 3: The dispersion was the same as dispersion 1, but the amount of desalted water initially added to the reactor was 232 g. A finely dispersed dispersion was obtained with a solid content of 50.5%, a pH of 7.4, a particle size D50 of 48 nm, and a viscosity of 387 mPa·s.

[0187] Preparation of dispersion 4: This was the same as dispersion 3, but 10.3 g of coconut oil-based wax in an aqueous dispersion with a solid content of 38% by weight was added to a mixture of desalinated water and dioctyl sulfosuccinic acid. A finely dispersed dispersion was obtained with a solid content of 50.4%, a pH of 7.4, a particle size D50 of 119 nm, and a viscosity of 457 mPa·s.

[0188] Viscosity values ​​are measured at 25°C using a Brookfield LVDV viscometer in a small 60 rpm sample adapter equipped with a spindle 18.

[0189] The pH value is measured at 25°C using a standard laboratory pH meter.

[0190] The solid content is measured using a Mettler Toledo Halogen humidity analyzer.

[0191] Particle size is measured using the Malvern Zetasizer Nano.

[0192] Method for producing a polymer dispersion according to method (b) of the present invention The wax was introduced into a polymer material produced by polymerizing acrylate monomers, and then the wax was mixed for about 15 minutes using a high-shear mixer (e.g., a Diaf mixer) to form the polymer material. Samples "Dispersion 1 + Wax 1" and "Dispersion 3 + Wax 2" were prepared using method (b).

[0193] Coating of substrate A laboratory-scale rod coater equipped with an infrared (IR) drying unit was used. All base sheets (fiber-based substrates) were ventilated under standard conditions, weighed, and then coated. The dispersion was pipetteed onto the sheet in front of the rod, and then the machine was started to allow the rod to spread the dispersion evenly onto the sheet. The layer was then dried for 60 seconds using the IR drying unit located above the rod.

[0194] Test method The barrier properties of one or more coating layers were measured by the following method.

[0195] Water vapor permeability test The water vapor transmission rate (WVTR) test was performed using a method conforming to the following standards: ASTM F-1249, ISO 15105-2:2003, ISO 15106-3:2003, and DIN 53122-2. The instrument used was a Systech Illinois 7000 analyzer. The sample to be tested was cut into a circle and placed on the sample holder. Vacuum grease was applied between the opening and the frame of the sample holder. The sample was placed with the surface to be tested facing downwards. The sample holder was then closed and the screws inside the holder were tightened. After completing the setup and placing the sample in place, the measurement was started. The unit of water vapor transmission rate (WVTR) is [g / m³]. 2 [d]. WVTR was measured at 23°C and 50% relative humidity.

[0196] Palm kernel fat test The palm kernel fat test method is based on the ISO 16532-1:2008 standard. In the palm kernel fat test, a specified amount of red palm kernel fat was placed on the sample. A weight of 50-55 g was placed on the sample. The sample was observed visually, and the time was recorded.

[0197] Cobb water resistance test Water absorption tests were conducted according to ISO 535 standards. The test periods were 300 seconds and 1800 seconds. The unit of the Cobb water resistance test results is [g / m²]. 2This is calculated for each case according to the size of the sample tested.

[0198] Blocking test In the inhibition test, the sample is cut into strips. The test always requires both the uncoated and coated sides of the fibrous substrate as counterparts. The sample is then placed in a machine and the counterparts are compressed together using a pressure of 150 bar at 40°C for 4 hours. The test results are evaluated based on how the counterparts break apart from each other, and assigned a numerical value from 1 to 5.

[0199] Contact angle and surface energy testing Surface energy was measured using a Fibro Dynamic Angle Tester. The test should be performed with both water and diiodomethane, starting with water. Fill the machine's syringe with the test solution and attach the appropriate capillary tube to the syringe. Ensure there is no air between the syringe and the capillary tube. Attach the setup to the applicator. Place the sample (15mm x 150mm piece) on the test holder. Control the tester using the software. Collect and analyze the test results thereafter.

[0200] result The results are shown in Tables 1-7.

[0201] Table 1 shows the barrier properties of one coating layer formed from a polymer dispersion according to the present invention on a substrate. All dispersions are anionic and aqueous.

[0202] The product of the aqueous dispersion according to the present invention is a polyacrylate stabilized with a surfactant.

[0203] Dispersion 1 and Dispersion 2 have the same monomer composition, but Dispersion 2 is polymerized in the presence of wax 1. The sample of Dispersion 1 + wax 1 is obtained by polymerizing the acrylate monomer and then mixing wax 1 with Dispersion 1.

[0204] [Table 1]

[0205] Polymerizing acrylate monomers in the presence of wax 1 improves their moisture resistance. Mixing wax 1 into the polymer dispersion after polymerization of the acrylate monomers further improves their moisture resistance.

[0206] Table 2 shows the barrier properties of a single coating layer formed from a polymer dispersion on a substrate. All dispersions are anionic and aqueous.

[0207] Dispersions 3 and 4, which are products of the aqueous dispersion according to the present invention, are polyacrylates stabilized with a surfactant.

[0208] Dispersion 3 and dispersion 4 have the same monomer composition, but dispersion 4 is polymerized in the presence of wax 2. The sample of dispersion 3 + wax 2 is obtained by polymerizing the acrylate monomer and then mixing wax 2 with dispersion 3.

[0209] [Table 2]

[0210] Polymerizing acrylate monomers in the presence of wax 2 improves their moisture resistance. Mixing wax 2 into the polymer dispersion after polymerization of the acrylate monomers further improves their moisture resistance.

[0211] Table 3 shows the barrier properties of a single coating layer formed from a polymer dispersion on a substrate. All dispersions are anionic and aqueous. Reference 1 is poly(styrene-n-butyl acrylate) stabilized with decomposed starch. Reference 2 is a polyacrylate stabilized with a surfactant. The monomers for Reference 2 were 2-ethylhexyl acrylate, methyl methacrylate, and methacrylic acid. References 1 and 2 do not contain wax. Dispersions 5, 6, and 7, which are aqueous dispersions according to the present invention, are surfactant-stabilized polyacrylates. The monomers constituting dispersions 5, 6, and 7 are the same, but the wax dispersion additives added to dispersions 5, 6, and 7 of the present invention differ. Dispersions 5, 6, and 7 are prepared by polymerizing the acrylate, then adding the wax dispersion to the polyacrylate, followed by the addition of the surfactant. The melting points of the wax in the product are dispersion 5 < dispersion 6 < dispersion 7.

[0212] [Table 3]

[0213] The wax additive improves water resistance compared to references 1 and 2. The best results for Cobb and WVTR are obtained with the lowest melting point wax in dispersion 5. References 1 and 2 show better grease barrier properties than dispersions 5, 6, and 7.

[0214] Table 4 shows the barrier properties of the double coating layer on the substrate. The first coating layer is reference 1, and the second layer is dispersion 5, 6, or 7 according to the present invention.

[0215] [Table 4]

[0216] The double layer exhibits improved oil resistance compared to the aqueous dispersion composition alone. The best barrier properties (moisture barrier and grease barrier) are obtained with the lowest melting point wax in dispersion 5.

[0217] Table 5 shows the barrier properties of the double coating layer on the substrate. The first coating layer is reference 2, and the second layer is dispersion 5, 6, or 7 according to the present invention.

[0218] [Table 5]

[0219] The double layer exhibits improved oil resistance compared to the aqueous dispersion composition alone. The best barrier properties (moisture barrier and grease barrier) are obtained with the lowest melting point wax in dispersion 5.

[0220] Furthermore, the surface energies of dispersions 1, 2, 3, and 4 are studied. Table 6 shows the polar components of dispersions 1 and 2 at 0.01 sec, 10 sec, 30 sec, 40 sec, and 60 sec. Table 7 shows the polar components of dispersions 3 and 4 at 0.01 sec, 10 sec, 30 sec, 40 sec, and 60 sec.

[0221] [Table 6]

[0222] Dispersion 1 is polymerized without the presence of wax 1. Table 1 shows that the polar components of dispersion 1 are at a significantly higher level compared to the polar components of dispersion 2.

[0223] [Table 7]

[0224] Dispersion 3 is polymerized without the presence of wax 2. Table 2 shows that the polar components of dispersion 3 are at a significantly higher level compared to the polar components of dispersion 4.

[0225] Tables 6 and 7 show that dispersions 1 and 3 have a polar component of 9–11 mN / m, while dispersions 2 and 4 have a polar component of 0–3 mN / m. In practice, dispersions 1 and 3 have the ability to adhere to each other, meaning that both the precoat layer and the topcoat layer can be made from the same polymer dispersion. On the other hand, dispersions 2 and 4 have lower levels of polar components compared to dispersions 1 and 3, and due to their lower polar component levels, the topcoat layer does not adhere properly to the precoat layer.

[0226] Various embodiments have been demonstrated. It should be understood that, in this specification, the words comprise, include, and contain are each used as open-ended expressions not intended to be exclusive.

[0227] The foregoing description provides a complete and useful description of the best mode currently intended by the inventors to carry out the invention, as non-limiting examples of specific implementations and embodiments. However, it will be apparent to those skilled in the art that the invention is not limited to the details of the embodiments shown above and can be carried out in other embodiments using equivalent means or in various combinations of embodiments without departing from the features of the invention.

[0228] Furthermore, some of the features of the embodiments disclosed in advance may be used to their advantage without corresponding use of other features. Therefore, the foregoing description is merely illustrative of the principles of the present invention and is not intended to limit it. Accordingly, the scope of the present invention is limited only by the appended claims.

Claims

1. A method for producing a polymer dispersion, wherein the method is (a) A step of polymerizing acrylate monomers in the presence of wax to produce a polymer dispersion; (b) A step of polymerizing acrylate monomers to produce a polymer material, and introducing wax into the polymer material to produce a polymer dispersion; (c) A step of polymerizing an acrylate monomer in the presence of a first wax to produce a polymer material, and introducing a second wax into the polymer material to produce a polymer dispersion; (d) A step of polymerizing acrylate monomers in the presence of a first wax and a second wax to produce a polymer dispersion; or (e) A method comprising the steps of polymerizing an acrylate monomer in the presence of a first wax to produce a polymer material (A), polymerizing an acrylate monomer in the presence of a second wax to produce a polymer material (B), and mixing polymer material (A) and polymer material (B) to produce a polymer dispersion.

2. The method according to claim 1, wherein the polymer dispersion is an aqueous polymer dispersion, preferably an anionic aqueous polymer dispersion.

3. The method according to claim 1 or 2, wherein the wax, the first wax, and the second wax are natural waxes, preferably stable natural waxes containing a crystalline phase, more preferably waxes containing a triclinic or orthorhombic crystalline phase, and most preferably waxes containing an orthorhombic phase.

4. The method according to any one of claims 1 to 3, wherein the wax, the first wax and / or the second wax have undergone one or more melting and solidification cycles.

5. The method according to any one of claims 1 to 4, wherein the plant wax of the wax, the first wax and the second wax comprises a fatty acid, an alcohol, an amide, an ester, a ketone, an aldehyde, an aromatic structure, a carboxylic acid, or a mixture thereof.

6. The method according to any one of claims 1 to 5, wherein the wax, the first wax, and the second wax are plant waxes, plant-based waxes, animal waxes, or animal-based waxes, preferably the wax is a plant wax or plant-based wax, more preferably the wax is a plant-based wax, and even more preferably the wax is selected from palm oil-based waxes, coconut oil-based waxes, candelilla wax, carnauba wax, rice bran wax, soybean wax, sugarcane wax, sunflower wax, canola wax, rapeseed wax, or mixtures thereof, most preferably selected from palm oil-based waxes, coconut oil-based waxes, or mixtures thereof.

7. The method according to any one of claims 1 to 6, wherein the acrylate monomer comprises a vinyl monomer, preferably the vinyl monomer comprises at least one first monomer (a) selected from either C1-C8 alkyl (meth)acrylates or mixtures thereof, at least one second monomer (b) selected from either vinyl monomers or mixtures thereof that optionally contain an aromatic structure, and / or at least one monomer (c) optionally comprising another vinyl monomer.

8. The method according to any one of claims 1 to 7, wherein the total amount of the wax in option (a), the total amount of the wax in option (b), and the total amounts of the first wax and the second wax in options (c), option (d), and option (e) are 0.1 to 45% by weight, preferably 0.5 to 25% by weight, more preferably 1 to 15% by weight, and most preferably 1.5 to 9.9% by weight, based on the total weight of the polymer dispersion.

9. The method according to any one of claims 1 to 8, wherein at least one additive is introduced into the polymer dispersion of options (a), (b), (c), (d), and (e).

10. A polymer dispersion, wherein the polymer dispersion is (a) A step of polymerizing acrylate monomers in the presence of wax to produce a polymer dispersion; (b) A step of polymerizing acrylate monomers to produce a polymer material, and introducing wax into the polymer material to produce a polymer dispersion; (c) A step of polymerizing an acrylate monomer in the presence of a first wax to produce a polymer material, and introducing a second wax into the polymer material to produce a polymer dispersion; (d) A step of polymerizing acrylate monomers in the presence of a first wax and a second wax to produce a polymer dispersion; or (e) A polymer dispersion formed by the steps of polymerizing an acrylate monomer in the presence of a first wax to produce a polymer material (A), polymerizing an acrylate monomer in the presence of a second wax to produce a polymer material (B), and mixing polymer material (A) and polymer material (B) to produce a polymer dispersion.

11. The polymer dispersion according to claim 10, wherein the polymer material has at least one glass transition temperature Tg in the range of -30°C to +95°C, preferably -25°C to +80°C, more preferably -20°C to +40°C, and even more preferably -14°C to +20°C.

12. The polymer dispersion according to claim 10 or 11, wherein the acrylate monomer comprises a vinyl monomer, preferably the vinyl monomer comprises at least one first monomer (a) selected from either C1-C8 alkyl (meth)acrylates or mixtures thereof, at least one second monomer (b) selected from either vinyl monomers or mixtures thereof that optionally contain an aromatic structure, and / or at least one monomer (c) optionally containing another vinyl monomer.

13. The polymer dispersion according to any one of claims 10 to 12, wherein the total amount of the wax in option (a), the total amount of the wax in option (b), and the total amounts of the first wax and the second wax in options (c), option (d), and option (e) are 0.1 to 45% by weight, preferably 0.5 to 25% by weight, more preferably 1 to 15% by weight, and most preferably 1.5 to 9.9% by weight, based on the total weight of the polymer dispersion.

14. The polymer dispersion according to any one of claims 10 to 13, wherein the polymer dispersion further comprises at least one additive.

15. The polymer dispersion according to any one of claims 10 to 14, wherein the viscosity of the polymer dispersion is ≤1500 mPa·s, preferably ≤800 mPa·s, and more preferably ≤400 mPa·s.

16. The polymer dispersion according to any one of claims 10 to 15, wherein the pH of the polymer dispersion is 3.0 to 9.5, preferably 5.5 to 9.0, and more preferably 7.0 to 8.5, as measured at 25°C.

17. The polymer dispersion according to any one of claims 10 to 16, wherein the polymer dispersion has a particle size D50 in the range of 50 to 800 nm, preferably 60 to 500 nm, and more preferably 80 to 350 nm.

18. Use of a composition comprising a polymer dispersion produced by any one of claims 1 to 9, or a polymer dispersion according to any one of claims 10 to 17, and optionally additional agents, for coating at least one layer on at least a portion of at least one surface of a substrate.

19. A coated substrate comprising at least one coating layer on at least a portion of at least one surface of the substrate, wherein the at least one coating layer is formed from a composition comprising a polymer dispersion produced by any one of claims 1 to 9, or a polymer dispersion according to any one of claims 10 to 17, and optionally additional agents.

20. A method for producing a multilayer coated substrate, A step of applying a pre-coat composition to at least a portion of at least one surface of a substrate to form a first coating, A method comprising the step of applying a composition comprising a polymer dispersion produced by the method according to any one of claims 1 to 9, or a polymer dispersion according to any one of claims 10 to 17, and optionally additional agents, onto the first coating to form a second coating.

21. The method according to claim 19, wherein the pre-coat composition is substantially wax-free, preferably wax-free.

22. The method according to claim 19 or 20, wherein the precoat composition comprises at least one component selected from a polymer dispersion or polymer solution, a stabilizer, a surfactant, a dispersant, a rheological modifier, a pigment, a pH adjuster, an antifoaming agent, a wax, or a mixture thereof, preferably a stabilizer, a surfactant, a dispersant, or a mixture thereof.

23. A multilayer coated substrate having at least two coatings, A first coating on at least a portion of at least one surface of the substrate, A multilayer coated substrate comprising a second coating on the first coating, the second coating comprising a composition comprising a polymer dispersion produced by any one of claims 1 to 9, or a polymer dispersion according to any one of claims 10 to 17, and optionally additional agents.

24. The multilayer coated substrate according to claim 22, wherein the first coating is substantially wax-free, preferably wax-free.

25. The multilayer coated substrate according to claim 22 or 23, wherein the precoat composition comprises at least one component selected from a polymer dispersion or polymer solution, a stabilizer, a surfactant, a dispersant, a rheological modifier, a pigment, a pH adjuster, an antifoaming agent, a wax, or a mixture thereof, preferably a stabilizer, a surfactant, a dispersant, or a mixture thereof.

26. A packaging material comprising a multilayer coated substrate according to any one of claims 23 to 25.

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