Aqueous aerosol vinyl acetate-ethylene adhesive compositions

Abstract

The present invention relates to a water-based aerosol adhesive composition using a vinyl acetate-ethylene (VAE) copolymer as an adhesive, and more particularly, to an environmentally-friendly water-based aerosol adhesive composition which can exhibit adhesion and spraying properties substantially equal to or higher than those of a conventional volatile solvent-based adhesive, while substantially inhibiting problems such as fire risk, legal restrictions on storage amount, toxicity to humans, and environmental load due to destruction of the ozone layer, and also achieving excellent spraying ability at a predetermined distance, thereby improving work convenience and productivity.

Description

[Technical Field]

[0001] This invention relates to an aqueous aerosol adhesive composition using vinyl acetate-ethylene (VAE) copolymer as a binder, and more specifically, to an aqueous aerosol VAE adhesive composition that does not contain volatile solvents and propellants, and is therefore environmentally friendly and can exhibit adhesion and spraying properties substantially equal to or higher than those of conventional volatile solvent-based adhesives. [Background Technology]

[0002] Currently, most adhesives are either solid or liquid products. However, applying these conventional solid and liquid adhesives uniformly to the surface of the substrate requires a significant amount of work and a relatively long working time. Furthermore, there can be operational and safety issues when using adhesives, such as foreign substances adhering to the operator's hands.

[0003] Recently, spray-on adhesives in aerosol form have been introduced to the market to increase work convenience and productivity. However, because these spray-on adhesives require the use of volatile organic solvents (VOCs) for application, potential problems arise such as fire risks, legal restrictions on storage, toxicity to humans, and environmental issues due to ozone layer depletion.

[0004] Meanwhile, U.S. Patent No. 7,713,365 discloses a waterborne acrylic aerosol adhesive composed of an acrylic polymer and water. Although these waterborne acrylic aerosol adhesives are environmentally friendly as they do not contain volatile solvents, surfactants or propellants must be used to maintain the stability of the acrylic polymer adhesive, and additional propellants or jet gases must be used to exhibit proper spraying capability. [Summary of the Invention]

[0005] [Technical Objectives]

[0006] Various aspects of embodiments of the present invention relate to an aqueous aerosol adhesive composition that can solve the problems of conventional spray adhesives based on volatile solvents and aqueous aerosol acrylic adhesives.

[0007] Specifically, various aspects of the embodiments of the present invention relate to an aqueous aerosol adhesive composition that is environmentally friendly by not requiring a separate propellant or jet gas, and exhibits adhesive and spraying properties substantially equal to or higher than those of conventional volatile solvent-based adhesives by including a vinyl acetate-ethylene (VAE) copolymer as an adhesive, the VAE copolymer being applicable in various fields with excellent adhesive properties and eco-friendliness, and the composition of the adhesive comprising such a VAE emulsion and water is adjusted to a predetermined ratio.

[0008] Other objects and advantages of the invention will be more clearly described by the following detailed description and claims.

[0009] [Technical solution to the problem]

[0010] According to one embodiment, an aqueous aerosol adhesive composition comprises: a vinyl acetate-ethylene (VAE) emulsion; a surfactant; and a water-containing non-volatile (non-VOC) solvent, wherein the vinyl acetate-ethylene emulsion has a solids content of 5% by weight or higher, a viscosity at 25°C in the range of 10 to 10,000 cp, a pH in the range of 2.0 to 10.0, and does not contain volatile propellants.

[0011] In some embodiments, the vinyl acetate / ethylene (VAE) copolymer contained in the vinyl acetate-ethylene emulsion may have a vinyl acetate (VA) content greater than 50% by weight relative to the total weight of the copolymer, and an ethylene content less than 50% by weight.

[0012] In some embodiments, the vinyl acetate / ethylene (VAE) copolymer contained in the vinyl acetate-ethylene emulsion may include at least one VAE copolymer with a glass transition temperature (Tg) in the range of -40°C to 35°C.

[0013] In some embodiments, the vinyl acetate-ethylene (VAE) copolymer may include: a first VAE copolymer with a glass transition temperature (Tg) of -40°C or higher and less than 0°C; and a second VAE copolymer with a glass transition temperature in the range of 0°C to 35°C.

[0014] In some embodiments, the mixing ratio of the first VAE copolymer and the second VAE copolymer can be in the range of 1:1 to 50:1 by weight.

[0015] In some embodiments, the surfactant may include at least one of anionic surfactants, cationic surfactants, and nonionic surfactants.

[0016] In some embodiments, the aqueous aerosol adhesive composition may include: a vinyl acetate-ethylene (VAE) emulsion in the range of 10 to 90% by weight relative to the total weight of the composition; a surfactant in the range of 0.1 to 10% by weight; and the remaining amount of a non-volatile solvent to meet 100% by weight.

[0017] In some embodiments, the non-volatile solvent may include water; or a mixture of water and alcohol.

[0018] In some embodiments, the mixing ratio of water and alcohol in the mixture can be in the range of 1:0.1 to 1:50.0 by weight.

[0019] In some embodiments, the aqueous aerosol adhesive composition may further comprise an acrylic polymer in the range of 0.1 to 10% by weight relative to the total weight of the composition.

[0020] In some embodiments, the acrylic polymer may include at least one of ethyl acrylate, 2-hydroxyethyl acrylate, and butyl acrylate.

[0021] In some embodiments, the aqueous aerosol adhesive composition may further include a tackifier in the range of 0.1 to 10% by weight relative to the total weight of the composition.

[0022] In some embodiments, the tackifier may include rosin and its derivatives, terpenes and modified terpenes, aliphatic, alicyclic and aromatic resins, hydrogenated hydrocarbon resins and mixtures thereof, terpene-phenol resins, polyethyleneimine, phenolic resins or mixtures thereof.

[0023] In some embodiments, the aqueous aerosol binder composition may further include at least one additive selected from defoamer, plasticizer, stabilizer, dispersant, corrosion inhibitor, pigment, dye, diluent, viscosity modifier and thickener.

[0024] In some implementations, the aqueous aerosol adhesive composition can be sprayed by manual pumping, mechanical means, or compressed air.

[0025] In some embodiments, the aqueous aerosol adhesive composition may be applied to at least one substrate selected from the group consisting of: paper, wood, metal, steel plate, film, ceramic tile, plastic, glass, resin, ceramic, concrete, carbon materials, fiber and composite materials thereof.

[0026] According to one embodiment, a method for preparing an aqueous aerosol adhesive composition includes: blending and then mixing a vinyl acetate-ethylene (VAE) emulsion; a surfactant; and a non-volatile solvent containing water, at a rotation speed of 1000 rpm or less, at a temperature in the range of 10 to 90°C for 1 to 3 hours; and transferring the prepared mixture into a storage tank or spray container to be sealed, and then sealing the prepared mixture.

[0027] In some implementations, a mixing mixer or homogenizer may be used in the mixing process.

[0028] [Effects of the Invention]

[0029] According to one or more embodiments of the present invention, an aqueous aerosol adhesive composition can achieve excellent adhesion and sprayability, while exhibiting environmental performance, by using a mixture of an emulsion comprising the vinyl acetate-ethylene (VAE) copolymer as an adhesive and water, and by adjusting the composition of the adhesive composition to a predetermined ratio.

[0030] Furthermore, according to one or more embodiments of the invention, the aqueous aerosol adhesive composition can achieve performance substantially equal to or higher than that of conventional commercially available volatile solvent-based adhesives, and it does not contain volatile solvents or propellants alone (e.g., jet gases), so problems such as fire risk, legal restrictions on storage, toxicity to humans, and environmental burdens caused by ozone layer depletion may not fundamentally occur.

[0031] Furthermore, according to one or more embodiments of the invention, the aqueous aerosol adhesive composition can increase productivity by improving ease of operation and handling, as it can be sprayed over a predetermined distance without the need for separate volatile propellants or jet gases. Therefore, it can be used not only in spray adhesive applications but also in a variety of other fields.

[0032] The effects of the invention are not limited to the exemplary descriptions above, and many more effects are included in this specification. [Image Description]

[0033] Figure 1 This is a schematic diagram illustrating a spray container provided with an aerosol adhesive according to an embodiment of the present invention and the process of spraying the aerosol adhesive from the spray container.

[0034] Figure 2 The graphs illustrate the initial spraying and recoating capabilities of the aerosol adhesives used in Examples 1-7 and Comparative Examples 2 and 3; and

[0035] Figure 3 The figures illustrate the paper adhesion and wood adhesion properties of the aerosol adhesives used in Examples 1-7 and Comparative Examples 2 and 3. [Detailed Implementation]

[0036] The invention will be described in detail below. However, the invention is not limited to the description below, and each element can be modified or used selectively as needed. Therefore, it should be understood that all changes, equivalents, and substitutions are included within the spirit and scope of the invention.

[0037] As used herein, the term "composition" includes mixtures of materials comprising the composition, as well as reaction and decomposition products formed from the materials of the composition. As used herein, the term "polymer" refers to a polymeric compound prepared by polymerizing monomers of the same or different kinds. Thus, the term "polymer" as used herein includes homopolymers (used to refer to polymers made from only one type of monomer, understood to mean that trace impurities may be incorporated into the polymer structure) and copolymers as defined below. In one instance, a polymer may optionally include polymers made from one or more different monomers, such as copolymers, ternary polymers, quaternary polymers, pentadienomers, etc., and may refer to any of random, block, graft, continuous, or gradient polymers.

[0038] Furthermore, throughout this specification, when a part “includes (or includes)” an element, this may mean that other elements may be further included, rather than excluding other elements, unless otherwise stated. Additionally, the terms of degree such as “about” and “substantially” used in this specification, when referring to manufacturing tolerances and material tolerances, indicate only numerical values ​​or values ​​close to those values, and the invention is not limited to those values.

[0039] Unless otherwise stated, all terms used in this specification (including technical and scientific terms) are to be used as they would be understood by one of ordinary skill in the art to which this invention pertains. Furthermore, terms defined in commonly used dictionaries are not to be ideally or excessively interpreted unless explicitly stated otherwise.

[0040] In this specification, volatile propellant refers to the term conventional propellants and / or jet gases used in the aerosol field. Examples may include Freon gases, liquefied natural gas (LNG), fluorocarbon-based (CFC, HCFC, HFC) and hydrofluorocarbon-based (HFA) propellants, and more specifically, propane, n-butane, isobutene compounds, chlorofluorocarbons, dimethyl ether, methyl ethyl ether, hydrofluorocarbons (HFA), hydrofluoroolefins, nitrogen, carbon dioxide, etc.

[0041] <Waterborne Aerosol Adhesive Composition>

[0042] According to one embodiment of the present invention, an aqueous aerosol adhesive composition comprises a vinyl acetate-ethylene (VAE) based emulsion; a surfactant; and a water-containing non-volatile (non-VOC) solvent.

[0043] Specifically, traditional solvent-based spray adhesives have drawbacks such as fire risk, legal restrictions on storage, toxicity to humans, and environmental impact due to ozone layer depletion. In the case of water-based acrylic spray adhesives, there is the problem that a gas must be sprayed to ensure proper spraying capability.

[0044] On the other hand, the aqueous aerosol adhesive composition according to one embodiment of the present invention differs from conventional volatile solvent-based adhesives and aqueous aerosol adhesives in that it can be applied in aerosol form without the use of harmful propellants and / or jet gases (e.g., dispersible gases). When such an aqueous aerosol adhesive composition is applied to a product, it can be sprayed at room temperature by manual pumping, mechanical or compressed air, and can also be smoothly sprayed at a predetermined distance, thereby improving ease of operation and productivity.

[0045] Furthermore, water-based aerosol adhesive compositions are environmentally friendly because they do not use volatile solvents and dispersible gases that cause ozone layer toxicity and damage, thus fundamentally solving the problems associated with the aforementioned volatile solvent-based spray adhesives and water-based acrylic spray adhesives. In addition, they can exhibit adhesion (e.g., tackiness) and spraying ability that are substantially equal to or higher than those of conventional commercially available volatile solvent-based spray adhesives.

[0046] The composition of the aerosol adhesive composition will be described in detail below.

[0047] Vinyl acetate-ethylene emulsion

[0048] The aqueous aerosol adhesive composition according to embodiments of the present invention comprises an emulsion containing a vinyl acetate-ethylene (VAE) copolymer, which has excellent adhesive properties and is environmentally friendly. This VAE copolymer is an adhesive component contained in the aqueous aerosol and exhibits excellent adhesion after being sprayed onto the substrate.

[0049] Vinyl acetate-ethylene (VAE) copolymers include conventional vinyl acetate (VA) polymerization units and ethylene (ethylene) polymerization units known in the art, and any VAE copolymer in which the content of vinyl acetate is greater than 50% by weight (wt%) relative to the total weight of the copolymer (or polymer) can be used without limitation.

[0050] The polymer is typically based on a vinyl acetate / ethylene (VAE) copolymer with a vinyl acetate content greater than 50% by weight (wt%), preferably ≥52% by weight, more preferably ≥55% by weight, and an ethylene content less than 50% by weight, preferably 1 to 40% by weight, and optionally other monomers that can be copolymerized therewith, in each case relative to the total weight of the monomer mixture, and in each case the total number of figures in weight % is 100% by weight. According to an exemplary embodiment of the invention, the vinyl acetate-ethylene (VAE) copolymer has a vinyl acetate (VA) content greater than 50% by weight to 99% by weight or less; and an ethylene content of 1% by weight or greater and less than 50% by weight relative to the total weight of the vinyl acetate / ethylene (VAE) copolymer.

[0051] Other suitable vinyl ester monomers are higher vinyl esters, such as those of carboxylic acids having 3-15 carbon atoms. Other suitable monomers selected from acrylates or methacrylates include, for example, esters of unbranched or branched alcohols having 1 to 15 carbon atoms. Preferred other vinyl aromatic monomers are styrene, methylstyrene, and vinyltoluene. Preferred other vinyl halide monomers are vinyl chloride. Preferred further olefin monomers are propylene and butene, and preferred dienes are 1,3-butadiene and isoprene.

[0052] Optionally, 0.1 to 10 wt% of auxiliary monomers may be copolymerized relative to the total weight of the monomer mixture. Preferably, 0.1-5 wt% of optional auxiliary monomers are used. Examples of optional auxiliary monomers include olefinically unsaturated monocarboxylic acids and dicarboxylic acids, olefinically unsaturated carboxamides and nitriles, and maleic anhydride and olefinically unsaturated sulfonic acids and their salts. Other embodiments of optional auxiliary monomers are pre-crosslinked comonomers, such as polyethylene unsaturated comonomers or post-crosslinked comonomers, examples being N-hydroxymethylacrylamide (NMA) and N-hydroxymethylmethacrylamide (NMMA). Epoxy-functionalized comonomers such as glycidyl methacrylate and silicone-functionalized comonomers such as methacryloxypropyltrialkoxysilane and vinyltrialkoxysilane are also suitable.

[0053] Preferably, it is a copolymer of 60 to 99% by weight vinyl acetate and 1 to 40% by weight ethylene;

[0054] Greater than 50% by weight of vinyl acetate with 1 to 40% by weight of ethylene and one or more other comonomers selected from vinyl esters having 1 to 12 carbon atoms in the carboxyl group (e.g., vinyl propionate, vinyl laurate, and vinyl esters of α-branched carboxylic acids having 5 to 12 carbon atoms, such as...). and copolymers of )

[0055] The copolymer comprises more than 50% by weight vinyl acetate, 1 to 40% by weight ethylene, and one or more comonomers selected from unbranched or branched alcohols having 1 to 15 carbon atoms, specifically methyl methacrylate, methyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate; wherein the copolymer may also each contain auxiliary monomers mentioned in the amounts, and in each case the total figures in weight percent are 100% by weight.

[0056] The selection of monomers and the weight fraction of comonomers are preferably chosen such that the glass transition temperature Tg is -40°C to +35°C, more preferably -40°C to +20°C, and most preferably -20°C to +20°C. The Tg of the polymer can be determined in a known manner by differential scanning calorimetry (DSC, DIN EN ISO 11357-1 / 2), for example, by a Mettler Toledo calorimeter DSC at a heating rate of 10 K / min as the midpoint temperature. Tg can also be approximately calculated in advance using the Fox equation. According to Fox TG, Bull. Am. Physics Soc. 1, 3, page 123 (1956), the following is true: 1 / Tg = x1 / Tg1 + x2 / Tg2 + ... + xn / Tgn, where xn represents the mass fraction of monomer n (wt% / 100), and Tgn is the glass transition temperature of the homopolymer of monomer n in Kelvin. The Tg values ​​of homopolymers are listed in Polymer Handbook 2nd Edition, J. Wiley & Sons, New York (1975).

[0057] The polymers are typically prepared in aqueous media, and preferably by emulsion or suspension polymerization processes, as described, for example, in WO 2010 / 057888A1. In this case, the polymer is obtained as an aqueous dispersion. Conventional protective colloids and / or emulsifiers, as described in WO2010 / 057888A1, can be used in the polymerization.

[0058] As a protective colloid, partially or completely hydrolyzed polyvinyl alcohol with a degree of hydrolysis of 80 to 100 mol-% is preferred; more particularly, a degree of hydrolysis of 80 to 94 mol-% in a 4% aqueous solution is preferred. Partially hydrolyzed polyvinyl alcohol with a viscosity of 1 to 30 mPas (Method, 20°C, DIN 53015). The protective colloid can be obtained by methods known to those skilled in the art and is typically added in the polymerization in an amount of 1-20% by weight relative to the total weight of the monomers.

[0059] The polymer in aqueous dispersion form will be dried using conventional methods. In a preferred embodiment, the polymer can be converted into an aqueous dispersion polymer powder by a spray drying process, such as that described in WO2010 / 057888A1. In this case, a drying aid, typically 3 to 30% by weight of the total polymer component based on the dispersion, is added. A preferred drying aid is the aforementioned polyvinyl alcohol. Additionally, an anti-blocking agent may be added during or after the drying step.

[0060] The polymer powder is commercially available, for example, from Wacker Chemie AG. and Dispersion powder.

[0061] Vinyl acetate / ethylene polymers can also be prepared by other methods, including solution polymerization or bulk (pure) polymerization. Polymers prepared by solution or bulk polymerization are preferably provided in a form with a relatively high surface area. For this purpose, the polymer can be extruded into pellets or granules by conventional methods, or otherwise prepared into small particle sizes. The use of water-dispersible powders obtained by emulsion or suspension polymerization followed by drying, especially spray drying, significantly reduces the asphalt mixing time, and therefore water-dispersible powders are highly preferred.

[0062] In one embodiment, the vinyl acetate-ethylene emulsion containing the VAE-based polymer has a solids content of 5% by weight or higher, a viscosity at 25°C in the range of 10 to 10,000 cp, and a pH in the range of 2.0 to 10.0. More specifically, the solids content can be in the range of 10 to 75% by weight, the viscosity can be in the range of 20 to 9,000 cp (relative to 25°C), and the pH can be in the range of 3.0 to 10.0. When the VAE emulsion has all the above-mentioned solids content, viscosity, and pH characteristics, a product that can be sprayed in aerosol form can be manufactured.

[0063] To further improve the adhesiveness of the adhesive composition, the present invention can blend at least one VAE copolymer or VAE copolymer-containing emulsion with different glass transition temperatures (Tg). That is, when the glass transition temperature (Tg) of the polymer is low, it is viscous, thereby increasing interfacial adhesion with other substrates and improving flowability. On the other hand, when the content increases beyond a predetermined range, the cohesive strength of the VAE copolymer adhesive itself may decrease. In the present invention, by using at least two VAE copolymers or VAE emulsions with different glass transition temperatures (Tg) in a predetermined ratio, high cohesive strength of the adhesive itself can be ensured while maintaining interfacial adhesion and flowability.

[0064] In one embodiment, the vinyl acetate-ethylene (VAE) copolymer may use at least one VAE copolymer with a glass transition temperature (Tg) in the range of -40°C to 35°C, and more specifically, may include a first VAE copolymer with a glass transition temperature (Tg) of -40°C or higher and less than 0°C; and a second VAE copolymer with a glass transition temperature in the range of 0°C to 35°C. In this document, the first VAE copolymer having a low Tg may exhibit an effect of improving initial adhesion to the surface of the adhesive.

[0065] In such an embodiment, the mixing ratio of the first copolymer and the second copolymer is not particularly limited, and the adhesion and flowability can be appropriately adjusted. For example, the mixing ratio of the first copolymer and the second copolymer can be in the range of 1:1 to 50:1 by weight, particularly 1:1 to 20:1 by weight, and even more particularly 5:1 to 15:1 by weight.

[0066] In an aqueous aerosol adhesive composition according to one embodiment of the invention, the content of the VAE-based emulsion is not particularly limited, and as an example, it can range from 10 to 90% by weight, and particularly from 20 to 85% by weight, relative to the total weight of the adhesive composition (e.g., 100% by weight). When the content of the VAE-based emulsion is within the above-mentioned numerical range, excellent adhesion, flowability, and processability can be exhibited without deteriorating physical properties.

[0067] surfactants

[0068] The aqueous aerosol adhesive composition according to embodiments of the present invention includes a surfactant.

[0069] Surfactants help to achieve uniform and stable dispersion of raw materials during mixing (e.g., blending) and are used to improve storage stability and processability. Furthermore, because surfactants adsorb or surround the surface of raw materials, they essentially prevent re-aggregation by maintaining a constant gap between the raw materials due to effects such as electrostatic repulsion or steric hindrance.

[0070] As a surfactant, surfactants or dispersants known in the art can be used without limitation, and may include, for example, at least one of anionic surfactants, cationic surfactants and nonionic surfactants.

[0071] Non-limiting examples of suitable surfactants may include sodium polyacrylate, saponified products of styrene (or olefin)-maleic anhydride copolymers, sodium formalin condensates of alkylnaphthalene sulfonates, sodium lignosulfonates, polyethylene glycol phenyl ethers, polyethylene glycol higher alkyl, ether dialkyl sulfosuccinates, alkylamines, alkanolamines, polycarboxylic acids, polyethyleneimine, sorbitan aliphatic ethylene oxide adducts, or mixtures thereof. Specifically, polycarboxylic acid surfactants may be used.

[0072] In an aqueous aerosol adhesive composition according to one embodiment of the invention, the content of surfactant is not particularly limited, and for example, it can be in the range of 0.1% to 10% by weight, and specifically 0.5% to 9% by weight, relative to the total weight of the adhesive composition (e.g., 100% by weight). When the content of surfactant is within the above-mentioned numerical range, excellent dispersibility and processability can be exhibited without deteriorating physical properties.

[0073] Non-volatile solvents

[0074] The aqueous aerosol adhesive composition according to embodiments of the present invention comprises conventional non-volatile (non-VOC) solvents known in the art.

[0075] In this invention, the use of volatile solvents known in the art, i.e., organic compounds (VOCs) having a vapor pressure sufficient to evaporate under normal conditions, is excluded.

[0076] There are no particular limitations on the applicable non-VOC solvents; for example, water alone or a mixture of water and alcohol can be used. Water is not particularly limited; distilled water or tap water can be used as an example. Alcohol is not particularly limited, and lower alcohols having 1 to 6 carbon atoms can be used as an example.

[0077] Furthermore, when using a mixture of water and alcohol, the mixing ratio of water and alcohol can be appropriately adjusted taking into account the spraying capability of the water-based aerosol adhesive composition. For example, the mixing ratio of water and alcohol can be in the range of 1:0.1 to 1:50.0 by weight, particularly 1:0.5 to 1:20.0 by weight, and more particularly 1:0.5 to 1:10.0 by weight.

[0078] In the aqueous aerosol adhesive composition according to embodiments of the present invention, the content of the non-volatile solvent is not particularly limited and can be, for example, a remaining amount that satisfies the total weight of the adhesive composition (e.g., 100% by weight). For example, it can be in the range of 5 to 80% by weight relative to the total weight of the adhesive composition.

[0079] acrylic polymers

[0080] The aqueous aerosol adhesive composition according to embodiments of the present invention may further include acrylic polymers.

[0081] To enhance the adhesiveness of the adhesive composition, such an acrylic polymer can be added, and there are no limitations on the use of conventional (meth)acrylic polymers known in the art.

[0082] Non-limiting examples of suitable acrylic polymers may include at least one of ethyl acrylate, 2-hydroxyethyl acrylate, and butyl acrylate. The content of the acrylic polymer is not particularly limited, and by way of example, it may range from 0.1% to 10% by weight relative to the total weight of the adhesive composition (e.g., 100% by weight).

[0083] Tackifier

[0084] The aqueous aerosol adhesive composition according to embodiments of the present invention may also contain conventional tackifiers known in the art.

[0085] Tackifiers are materials added to improve the initial adhesion and / or adhesion durability between objects to be bonded, and adhesive promoters or tack improvers known in the art may be used without limitation.

[0086] Suitable examples of tackifiers may include rosin and its derivatives (e.g., rosin esters); terpenes and modified terpene resins; aliphatic, alicyclic, and aromatic resins; hydrogenated hydrocarbon resins and mixtures thereof; terpene-phenol resins, polyethyleneimine, phenolic varnishes, or mixtures thereof. Specific examples may include rosin, rosin ester resins, polyterpenes and aromatically modified polyterpenes, coumarin-indene resins, hydrocarbon resins (e.g., α-pinene resins, β-pinene resins, limonene resins, aliphatic hydrocarbon resins, aromatically modified hydrocarbon resins); or combinations thereof.

[0087] In one embodiment of the invention, the amount of tackifier is not particularly limited and can be in the range of 0.1 to 10% by weight relative to the total weight of the adhesive composition (e.g., 100% by weight).

[0088] additive

[0089] In addition to the components described above, without impairing the effects of the present invention, the aerosol adhesive composition according to embodiments of the present invention may, without limitation, use at least one additive known in the art.

[0090] Non-limiting examples of suitable additives may include defoamers, plasticizers, stabilizers, dispersants, corrosion inhibitors, pigments, dyes, diluents, viscosity modifiers, thickeners, etc. These may be used alone or in combination of two or more. The content of the additive is not particularly limited and can be appropriately adjusted within the range known in the art. For example, the content of the at least one additive may be from 0.01 to 10% by weight, particularly from 0.03 to 5% by weight, relative to the total weight of the adhesive composition.

[0091] As plasticizers, conventional plasticizer components known in the art can be used without limitation. For example, hydrocarbon oils (e.g., aromatic hydrocarbons, alkanes, or cycloalkanes), hydrocarbon resins, polyterpenes, rosin esters, phthalates (e.g., terephthalates), phosphate esters, diesters, fatty acid esters, polyethers (e.g., alkylphenyl ethers), epoxy resins, sebacic acid esters, adipate esters, citrate esters, trimellitate esters, dibenzoic acid esters, or combinations thereof.

[0092] Furthermore, corrosion inhibitors are materials capable of substantially preventing chemical reactions between the composition and the metal constituting the container. Non-limiting examples of suitable corrosion inhibitors may include sulfonates, morpholines, benzotriazoles, various amines, sodium benzoate, sodium nitrite, quaternary ammonium nitrite, sodium silicate, sodium tetraborate, ammonium nitrite, acetylene derivatives, sodium molybdate, formamide, or mixtures thereof.

[0093] In addition, examples of antioxidants may include phenol, phosphites, thioesters, amines, sterically hindered phenols, copolymers of 4-ethylphenol, reaction products of dicyclopentadiene and butene, or combinations thereof.

[0094] An aerosol adhesive composition according to one embodiment of the invention can be prepared by blending (e.g., mixing) the above-mentioned VAE emulsion, surfactant, non-volatile solvent, and other additives such as acrylic polymers, emulsifiers, tackifiers, defoamers, plasticizers, etc., as needed, and then mixing and stirring the mixture according to conventional methods known in the art until the VAE-based copolymer contained in the VAE emulsion is properly dispersed. Further additives or solvents may be added if necessary.

[0095] There are no particular limitations on the mixing method; for example, mixers known in the art, such as conventional mixers, homogenizers, dispersants, homogenizing mixers, general-purpose mixers, planetary mixers, or kneaders, can be used. Furthermore, as an example of mixing conditions, it can be carried out at a temperature of 10 to 90°C at a speed of 1000 rpm or less for 1 to 3 hours, particularly at a speed of 200 to 800 rpm in the range of 10 to 70°C. In such embodiments, the emulsion system may break down during prolonged stirring at speeds exceeding 1000 rpm, and prolonged heating at temperatures exceeding 90°C may affect the physical properties; therefore, careful mixing under the aforementioned mixing conditions is desirable.

[0096] When the prepared mixture is exposed to air, it can be cured, and therefore can be stored in a tank or spray container with limited exposure to air before use of the aerosol adhesive composition. Thus, in one embodiment of the invention, the prepared mixture can be transferred to a sealed tank or spray container to cure without exposure to air, and then sealed according to conventional methods known in the art to manufacture the final product.

[0097] In one embodiment, the aerosol adhesive composition of the present invention may include, relative to the total weight of the composition (e.g., 100% by weight), a vinyl acetate-ethylene (VAE) emulsion in the range of 10 to 90.0% by weight; a surfactant in the range of 0.1 to 10% by weight; and the remainder of a non-volatile solvent to satisfy 100% by weight of the composition. In such embodiments, the content of the aqueous non-volatile solvent is not particularly limited and may be, for example, in the range of 5 to 80% by weight. If desired, additives or solvents in the art may be additionally included, and their content may be the remainder to satisfy the total weight of the composition (e.g., 100% by weight).

[0098] In one embodiment, the viscosity of the aerosol adhesive composition at 25°C can be in the range of 10 to 10,000 cp, particularly 20 to 9,000 cp. Furthermore, the solids content can be in the range of 10 to 80% by weight, particularly 10 to 70% by weight.

[0099] The aerosol adhesive composition according to one embodiment of the invention, as described above, can satisfy the properties required of an aerosol adhesive (e.g., adhesion, sprayability, etc.) and can ensure ease of operation and productivity, even if it does not contain harmful volatile propellants or jet gases. In particular, unlike conventional aqueous acrylic adhesives, it can be sprayed using conventional spraying methods known in the art, such as manual pumping, mechanical spraying, or compressed air. In this case, the internal pressure of the container containing the aerosol adhesive composition is not particularly limited, as long as it can be sprayed. For example, in the case of mechanical spraying or compressed air, it can be 10 bar or less at room temperature, and specifically in the range of 0.5 to 9.0 bar.

[0100] Furthermore, since the aerosol adhesive composition can be smoothly sprayed at a predetermined distance, it has the advantage of increasing productivity by improving ease of operation and handling. In this embodiment, there is no particular limitation on the allowable spray interval distance, and it can be, for example, in the range of 1 to 150 cm.

[0101] In one embodiment, the aerosol adhesive composition may satisfy at least one of the following physical properties (i) to (iv), and more specifically, may satisfy two or more, and more specifically, all of (i) to (iv). For example, (i) a spray diameter of 3.5 cm or greater according to ASTM D4041, (ii) a re-spray diameter of 3.5 mm or greater after 10 days; (iii) an adhesion to paper of 2.5 or greater according to Pappi testing; and (iv) a maximum adhesion (e.g., bond strength) to wood exceeding 0.5 kgf according to DIN EN 204 / DIN EN205.

[0102] In this invention, temporary fixation or high-performance use (high adhesion) can be achieved by controlling the components constituting the aerosol adhesive composition and the composition thereof.

[0103] As one embodiment of the aerosol adhesive composition for temporary fixation, (i) the spray diameter according to ASTM D4041 may be 3.5 cm or greater, particularly in the range of 3.5-5.0 cm, (ii) the re-spray diameter after 10 days may be 3.5 cm or greater, (iii) the adhesion to paper according to Pappi test may be 2.5 or greater, and (iv) the maximum adhesion to wood according to DIN EN 204 / DIN EN 205 may exceed 0.5 kgf, particularly in the range of 1.0 to 6.0 kgf.

[0104] Furthermore, as one embodiment of the aerosol adhesive composition for high-performance applications, (i) the spray diameter according to ASTM D4041 can be 3.5 cm or greater, particularly in the range of 3.5-5.0 cm, (ii) the re-spray diameter after 10 days can be 3.5 cm or greater, (iii) the adhesion to paper according to Pappi testing can be 4.0 or greater, particularly in the range of 4.0 to 5.0, and (iv) the maximum adhesion (e.g., tack) to wood according to DIN EN 204 / DIN EN 205 can exceed 5.5 kgf, particularly in the range of 7.5 to 30.0 kgf.

[0105] A water-based aerosol adhesive composition according to one embodiment of the invention can be contained (e.g., included) in conventional aerosol devices known in the art.

[0106] There are no particular limitations on this aerosol delivery device, and it can be, for example, a conventional containment container with valves and / or spraying devices known in the art. See also Figure 1 The aerosol device may include: a container 1 containing an aqueous aerosol adhesive composition 2; a nozzle for spraying the composition 2 in the form of an aerosol 5; and a hose 3 disposed between the container 1 and the nozzle to supply the adhesive composition 2 from the container 1 to the nozzle. Additionally, a suction pump may be included.

[0107] To effectively spray the aerosol adhesive composition contained in the containment container, a propellant and / or a jet gas may be further included. This propellant and / or jet gas does not include conventionally hazardous propellants or jet gases, and may use at least one or more of carbon dioxide, nitrogen, and compressed air known in the art, and may have an internal pressure of 10 bar or lower at room temperature prior to spraying.

[0108] The aqueous aerosol adhesive composition according to one embodiment of the present invention can be applied to substrates having various materials and / or shapes, thereby exhibiting excellent adhesion.

[0109] The substrate is not particularly limited, as long as it is a material that can be sprayed and applied with a water-based aerosol adhesive to bond to other substrates. For example, it can be applied to at least one substrate selected from the group consisting of: paper, wood, metal, steel plate, film, ceramic tile, plastic, glass, resin, ceramic, concrete, carbon materials, fiber and composite materials thereof.

[0110] Since the aerosol adhesive composition according to one embodiment of the present invention, as described above, not only ensures excellent adhesion and spraying ability but also has eco-friendliness, it can be effectively used as a sprayable adhesive and can be applied without limitation to a variety of fields.

[0111] The present invention will be described in detail below by way of examples. However, the following examples are merely illustrative of the invention, and the invention is not limited to the following examples.

[0112] [Reference Example]

[0113] The vinyl acetate-ethylene-based emulsions (VAE dispersions) used in the following examples and experimental cases are the VINNAPAS dispersion product of WACKER Chemical. Furthermore, distilled water was used as the water source.

[0114] [Examples 1-7: Preparation of Aerosol Adhesive Compositions]

[0115] As shown in Table 1 below, vinyl acetate-ethylene (VAE) emulsion, water, ethanol, surfactant, and additives were added at predetermined weight ratios, and then mixed at 400 rpm for 1 hour at room temperature (approximately 25°C) using a homogenizer until the VAE copolymer contained in the VAE emulsion was properly dispersed, thereby preparing the aerosol adhesive compositions of Examples 1 to 7. In Table 1 below, the mixing ratios of each composition are in wt%.

[0116] [Table 1]

[0117]

[0118] (Note) 1) First VAE copolymer: VINNAPAS EAF7012 [Tg: -14~-16℃, viscosity: 100~500cp (25℃), pH: 6~8, solids content: 54~56% by weight]

[0119] 2) Second VAE copolymer: VINNAPAS EP3360 [Tg: 5~7℃, viscosity: 3000~8000cp (25℃), pH: 5~6, solids content: 59~62% by weight]

[0120] [Experimental Example: Evaluation of the Physical Properties of Aerosol Adhesive Compositions]

[0121] To determine the suitability of a VAE (vinyl acetate-ethylene)-based aqueous aerosol adhesive composition according to one embodiment of the present invention, spraying ability, adhesion to paper (e.g., paper tear adhesion), and adhesion to wood were evaluated compared with conventional volatile solvent-based spray adhesives.

[0122] For example, such as Figure 1As shown, the aerosol adhesive compositions 2 prepared in Examples 1 to 7 were placed in container 1, and the aerosol adhesive 2 was sprayed from container 1 onto substrate 6. The physical properties of the applied adhesive 7 were then evaluated using the test methods shown in Table 2 below. The results are shown in Tables 3 and 4 respectively. Figures 2 to 3 In the control group, ordinary tap water was used in Comparative Example 1, while typical volatile solvent-based spray adhesives were used in Comparative Examples 2 and 3, respectively.

[0123] <Methods for evaluating physical properties>

[0124] (1) Evaluation of the adhesive’s spraying ability (initial spraying ability)

[0125] Specifically, after filling the spray container with the aqueous vinyl acetate-ethylene (VAE) aerosol adhesive compositions prepared in Examples 1 to 7, the adhesive was sprayed for approximately three minutes by manually (e.g., by hand) operating the stick of a sprayer with a 0.2 mm outlet diameter horizontally at a height of approximately 10.2 cm (=4 inches) above the A4-sized paper serving as the substrate, according to the test conditions in Table 2 below in ASTM D4041-05 "Standard Practice for Determining Spray Patterns of Mechanical Pump Dispensers". In this case, depending on the size and shape of the spraying device tip, the adhesive was sprayed in aerosol form and applied to the paper serving as the substrate in a circular or elliptical shape. To evaluate the spraying ability, the length of the adhesive sprayed onto the paper serving as the substrate was measured on the X and Y axes after spraying. As a control group, water without adhesive (Comparative Example 1) and spray adhesives based on volatile solvents (Comparative Examples 2 to 3) were used to evaluate the spray patterns and spraying ability in a relative manner. Here, ordinary tap water used as Comparative Example 1 exhibits a constant circular shape after spraying, and its X-axis and Y-axis lengths (diameters) average about 5 cm.

[0126] (2) Evaluation of adhesive recoating ability

[0127] Ten days after the initial spraying tests described above, the spray patterns and spraying capability were evaluated in a relative manner by re-spraying the aqueous VAE (vinyl acetate-ethylene) aerosol adhesive compositions of Examples 1 to 7, according to ASTM D4041-05 "Standard Practice for Determining Spray Patterns of Mechanical Pump Dispensers". As a control group, spray adhesives based on volatile solvents (Comparative Examples 2 and 3) were used.

[0128] (3) Evaluation of adhesion to paper

[0129] The experiment was conducted in the same manner as the Tappi test. Specifically, paper was cut into large sections of 22cm (length) x 10cm (width), then folded in the center so that the top and bottom dimensions were 11cm (length, width) x 10cm. To prevent complete adhesion, each top and bottom edge was folded outwards by about 1cm, and then aerosol adhesive (sprayed adhesive) was evenly sprayed onto one side of the 10cm (length) x 10cm (width) section to apply the adhesive. After evenly stacking the top and bottom edges, it was allowed to dry for about 10 minutes. Then, the opposite side without adhesive was pulled to check for tears in the backing paper, and the remaining area was recorded relative to the total area. In this case, the adhesive area was approximately 100cm². 2 At that time, the level of adhesion between the paper and the paper was rated as 5, when 80cm 2 When it is 4, when it is 60cm 2 When it is 3, when it is 40cm 2 When it is 2, when it is 20cm 2 When it is 1, and when it is 0cm 2 The time is 0.

[0130] (4) Evaluation of adhesion to wood

[0131] After the aqueous aerosol adhesive compositions prepared in Examples 1 to 7 were filled into a spray container, they were sprayed onto wood samples according to DIN EN 204 / DIN EN 205 "Classification of thermoplastic wood adhesives for non-structural applications" / "Wood adhesives for non-structural applications - Determination of tensile shear strength of lap joints" to evaluate adhesion. In this case, the maximum load of the adhesion test results with wood was recorded.

[0132] [Table 2]

[0133]

[0134] [Table 3]

[0135]

[0136] Here, the spraying ability index is evaluated by the average X-axis length (diameter) of the adhesive application surface formed after spraying, and the adhesion index with paper is evaluated by the adhesive bonding area formed after spraying. Furthermore, the adhesion index with wood is evaluated by the maximum load of the adhesive after spraying.

[0137] It is understood that in the mixing ratio of the aerosol adhesive composition according to an embodiment of the present invention, as the content of VAE emulsion decreases and the content of ethanol and water increases, the spraying ability (spraying performance) is improved, while the adhesive area decreases in the adhesion test with paper (Tappi test). Therefore, in one embodiment of the present invention, it has been found that the spraying ability, adhesion to paper, etc., can be controlled by adjusting the mixing ratio of the aerosol adhesive composition.

[0138] As shown in Table 3, in the case of Comparative Example 2 (3M, Graphic Art 75 Spray, used for temporary fixation), which is a representative volatile solvent-based spray adhesive, the initial spraying capacity and respraying capacity are both 3.8 cm, the adhesion to paper is 3 cm, and the maximum adhesion to wood is 1.2 kgf. On the other hand, in the case of the water-based VAE aerosol adhesive of Example 2 of the present invention, the initial spraying capacity and respraying capacity are both 3.8 cm, the adhesion to paper is 2.8 cm, and the maximum adhesion to wood is 4.7 kgf, showing a spraying capacity and adhesion length to paper that are substantially equal to or higher than those of Comparative Example 2. In particular, in terms of adhesion to wood, the adhesive of Example 2 exceeds 3.5 kgf compared to Comparative Example 2, which is a volatile solvent-based spray adhesive, representing an improvement of approximately three times.

[0139] Furthermore, in the case of Comparative Example 3 (3M, HighStrength 99 Spray, for high performance), which is another spray adhesive based on volatile solvents, the initial spraying capacity and respraying capacity are both 4.0 cm, the adhesion to paper is 4.8 cm, and the adhesion to wood is 7.6 kgf. On the other hand, the aqueous VAE aerosol adhesives of Examples 3 to 7 of the present invention exhibited initial spraying capacity, respraying capacity, adhesion to paper, and adhesion to wood that are substantially equal to or higher than those of Comparative Example 3. Specifically, in the cases of Examples 4 and 7, the spraying capacity is 4.5 cm or greater, the adhesion to paper is 4.8 cm or greater, and the maximum adhesion to wood is 9.1 kgf and 11.6 kgf, respectively, which are equal to or higher than those of currently available high-performance volatile spray adhesives on the market. Specifically, regarding adhesion to wood, Example 4 showed 9.1 kgf, representing an improvement of approximately 20% or more compared to Comparative Example 3 (3M, High Strength 99 Spray for high performance), and Example 7 showed 11.6 kgf, representing an improvement of approximately 53% or more compared to Comparative Example 3.

[0140] Meanwhile, in Example 6, where the tackifier is included in a predetermined amount, the viscosity and tackiness (e.g., stickiness) of the aerosol adhesive composition increase, and the initial spray diameter and applied area decrease during recoating. As described above, it has been found that the sprayability and adhesion of the aerosol adhesive composition can be controlled by controlling the content of the tackifier.

[0141] Based on the above results, the aqueous VAE aerosol adhesive according to one embodiment of the present invention is not only environmentally friendly because it does not use volatile solvents (VOCs) or propellants alone, but also achieves the performance required as an adhesive, which is equal to or higher than the performance of conventional volatile solvent spray adhesives. Therefore, it can be recognized that it can be effectively used as an environmentally friendly aerosol adhesive.

[0142] Figure Labels

[0143] 1. Adhesive spray container

[0144] 2. Adhesive

[0145] 3. Entrance

[0146] 4. Spray nozzle with a spray valve or button

[0147] 5. Aerosol adhesives

[0148] 6. Substrate

[0149] 7. The applied adhesive

Claims

1. An aqueous aerosol adhesive composition comprising: Vinyl acetate-ethylene (VAE) emulsion; Surfactants; and Non-volatile solvents containing water, The non-volatile solvent may be water alone, or a mixture of water and an alcohol having 1 to 6 carbon atoms. The vinyl acetate-ethylene emulsion has a solids content of 5% by weight (wt%) or higher, a viscosity at 25°C in the range of 10 to 10,000 cp, and a pH in the range of 2.0 to 10.

0. The vinyl acetate-ethylene (VAE) emulsion comprises: A first VAE copolymer with a glass transition temperature (Tg) of -40°C or higher and less than 0°C; and A second VAE copolymer with a glass transition temperature in the range of 0°C to 35°C. The glass transition temperature of the VAE copolymer is determined by differential scanning calorimetry according to DIN EN ISO 11357-1 / 2, and the mixing ratio of the first VAE copolymer and the second VAE copolymer is in the range of 1:1 to 20:1 by weight. The vinyl acetate-ethylene (VAE) copolymer contained in the vinyl acetate-ethylene emulsion has a vinyl acetate (VA) content greater than 50% by weight relative to the total weight of the copolymer, and an ethylene content less than 50% by weight. The aqueous aerosol binder composition thereof does not contain volatile propellants selected from the group consisting of: Freon gas, liquefied natural gas, fluorocarbon-based and hydrofluoroalkane-based propellants, propane, n-butane, isobutene compounds, chlorofluorocarbons, dimethyl ether, methyl ethyl ether, hydrofluoroalkane, hydrofluoroolefins, nitrogen, and carbon dioxide. Relative to the total weight of the composition, it comprises: The vinyl acetate-ethylene (VAE) emulsion is in the range of 10 to 90% by weight; The surfactant is present in amounts ranging from 0.1% to 10% by weight.

2. The aqueous aerosol adhesive composition according to claim 1, wherein the vinyl acetate-ethylene (VAE) copolymer contained in the vinyl acetate-ethylene emulsion has a vinyl acetate (VA) content of ≥52% by weight relative to the total weight of the copolymer; and an ethylene content of 1-40% by weight.

3. The aqueous aerosol adhesive composition according to claim 1, wherein the surfactant comprises at least one of anionic surfactants, cationic surfactants, and nonionic surfactants.

4. The aqueous aerosol adhesive composition according to claim 1, wherein the mixing ratio of water and alcohol in the mixture is in the range of 1:0.1 to 1:50.0 by weight.

5. The aqueous aerosol adhesive composition according to claim 1, further comprising an acrylic polymer in the range of 0.1 to 10% by weight relative to the total weight of the composition.

6. The aqueous aerosol adhesive composition according to claim 5, wherein the acrylic polymer comprises at least one selected from ethyl acrylate, 2-hydroxyethyl acrylate, and butyl acrylate.

7. The aqueous aerosol adhesive composition according to claim 1, wherein the composition further comprises a tackifier in the range of 0.1 to 10% by weight relative to the total weight of the composition.

8. The aqueous aerosol adhesive composition according to claim 7, wherein the tackifier comprises rosin, terpenes and modified terpenes, aliphatic, alicyclic and aromatic resins, hydrogenated hydrocarbon resins and mixtures thereof, terpene phenolic resins, polyethyleneimine, phenolic varnish, or mixtures thereof.

9. The aqueous aerosol adhesive composition according to claim 1, further comprising at least one additive selected from defoamers, plasticizers, stabilizers, dispersants, corrosion inhibitors, pigments, dyes, diluents, viscosity modifiers, and thickeners.

10. The aqueous aerosol adhesive composition according to claim 1, wherein the aqueous aerosol adhesive composition can be sprayed by manual pumping, mechanical means or compressed air.

11. A method of applying the aqueous aerosol adhesive composition according to claim 1 to at least one substrate, said substrate being selected from the group consisting of: paper, wood, metal, film, ceramic tile, plastic, glass, resin, ceramic, concrete, carbon material, fiber, and composite materials thereof.

12. A method for preparing the aqueous aerosol adhesive composition according to claim 1, the method comprising: The vinyl acetate-ethylene (VAE) emulsion, the surfactant, and the water-containing non-volatile solvent are blended at a speed of 1000 rpm or less and at a temperature ranging from 10 to 90°C for 1 to 3 hours; and The prepared mixture is transferred to a storage tank or spray container to be sealed, and then the prepared mixture is sealed.

13. The method of claim 12, wherein a mixing mixer or homogenizer is used in the mixing process.

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