[TECHNICAL FIELD] The present invention relates to an aqueous aerosol adhesive composition using a vinylacetate-ethylene (VAE) copolymer as a binder, and more particularly, to an aqueous aerosol VAE adhesive composition that does not include volatile solvents and propellants, thus being eco-friendly, and may exhibit adhesion and spray characteristics substantially equal to or higher than that of conventional volatile solvent-based adhesives.

[DISCUSSION OF RELATED ART]

Currently, most of adhesives are solid or liquid products. However, in order to uniformly apply such conventional solid and liquid adhesives to a surface of the adherend to be applied therewith, a lot of work processes are required, and a relatively long working time is required as well. In addition, while working with the adhesives, there may be problems in handling and safety, such as sticking of foreign substances to the hands of the operator.

Recently, in order to increase work convenience and productivity, a spray-type adhesive sprayed in the form of an aerosol has been introduced in the market. Since these spray-type adhesives indispensably use volatile organic solvents (VOC) for ease of spraying, problems such as fire risk, legal restrictions on storage amounts, toxicity to humans, and environmental load due to the destruction of the ozone layer may arise. Meanwhile, U.S. Patent No. 7,713,365 discloses an aqueous acrylic aerosol adhesive composed of an acrylic polymer and water. While these aqueous acrylic aerosol adhesives do not contain volatile solvents, thus being environmentally friendly, it is necessary to use surfactants or propellants to maintain the stability of the acrylic polymer adhesives, and it is also necessary to use additional propellants or spray gases in order to exhibit proper spray ability.

[DETAILED DESCRIPTION OF THE INVENTION] [TECHNICAL OBJECTIVES]

Aspects of embodiments of the present invention are directed to an aqueous aerosol adhesive composition capable of solving both the problems of the conventional volatile solvent-based spray adhesives and the aqueous aerosol-acrylic adhesives. Specifically, aspects of embodiments of the present invention are directed to an aqueous aerosol adhesive composition that does not require a separate propellant or spray gas to be eco-friendly and exhibits adhesion and spray characteristics substantially equal to or higher than that of conventional volatile solvent- based adhesives by including, as a binder, a vinylacetate-ethylene (VAE) copolymer which is applied to various fields with excellent adhesion performance and eco-friendliness and adjusting a composition of the adhesive including such a VAE emulsion and water to a predetermined ratio.

Other objectives and advantages of the present invention may be more clearly described by the following detailed description and claims. [TECHNICAL SOLUTION TO THE PROBLEM]

According to an embodiment, an aqueous aerosol adhesive composition includes: a vinylacetate-ethylene (VAE) emulsion; a surfactant; and a non-volatile (non-VOC) solvent containing water, wherein the vinylacetate-ethylene emulsion has a solid content of 5 percent by weight (wt%) or more, a viscosity in a range from 10 to 10,000 cps at 25°C; and a pH in a range from 2.0 to 10.0, and does not contain a volatile propellant.

In some embodiments, a vinylacetate-ethylene (VAE) copolymer contained in the vinylacetate-ethylene emulsion may have a vinylacetate (VA) content of more than 50 wt% with respect to the total weight of the copolymer; and an ethylene content of less than 50 wt%.

In some embodiments, the vinylacetate-ethylene (VAE) copolymer contained in the vinylacetate-ethylene emulsion may include at least one VAE copolymer having a glass transition temperature (Tg) in a range from -40°C to 35°C.

In some embodiments, the vinylacetate-ethylene (VAE) copolymer may include: a first VAE copolymer having a glass transition temperature (Tg) of -40°C or more and less than 0°C; and a second VAE copolymer having a glass transition temperature in a range from 0°C to 35°C.

In some embodiments, a mixing ratio of the first VAE copolymer and the second VAE copolymer may be in a range from 1 : 1 to 50 : 1 by weight.

In some embodiments, the surfactant may include at least one of an anionic surfactant, a cationic surfactant, and a non-ionic surfactant.

In some embodiments, the aqueous aerosol adhesive composition may include: with respect to the total weight of the composition, the vinylacetate-ethylene (VAE) emulsion in a range from 10 to 90 wt%; the surfactant in a range from 0.1 to 10 wt%; and the non-volatile solvent in a remaining amount to satisfy 100 wt%.

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

In some embodiments, a mixing ratio of water and alcohol in the mixture may be in a range from 1 : 0.1 to 1 : 50.0 by weight. In some embodiments, the aqueous aerosol adhesive composition may further include an acrylic polymer in a range from 0.1 to 10 wt% with respect to the total weight of the composition.

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

In some embodiments, the composition may further include a tackifier in a range from 0.1 to 10 wt% with respect to the total weight of the composition.

In some embodiments, the tackifier may include rosin and derivatives thereof, terpene and modified terpene, aliphatic, alicyclic and aromatic resins, hydrogenated hydrocarbon resins and mixtures thereof, terpene-phenol resins, polyethyleneimines, novolacs, or mixtures thereof.

In some embodiments, the aqueous aerosol adhesive composition may further include at least one additive of a defoaming agent, a plasticizer, a stabilizer, a dispersant, a corrosion inhibitor, a pigment, a dye, a diluent, a viscosity modifier, and a thickener. In some embodiments, the aqueous aerosol adhesive composition may be sprayable by manual pumping, mechanical or compressed air. 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, tile, plastic, glass, resin, ceramic, concrete, carbon material, fiber, and composite materials thereof. According to an embodiment, a method for preparing the aqueous aerosol adhesive composition includes: blending and then mixing the vinylacetate-ethylene (VAE) emulsion; the surfactant; and the non-volatile solvent containing water at 1000 rpm or less at a temperature in a range from 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.

In some embodiments, a mixing mixer or homogenizer may be used in the mixing.

[EFFECTS OF THE INVENTION]

According to one or more embodiments of the present invention, an aqueous aerosol adhesive composition may achieve both excellent adhesion and spray ability, while exhibiting eco-friendly properties, by including, as a binder, a vinylacetate-ethylene (VAE) copolymer, using a mixture of an emulsion including the VAE copolymer with water, and adjusting a composition of the adhesive composition to a predetermined ratio.

In addition, according to one or more embodiments of the present invention, an aqueous aerosol adhesive composition may achieve performance substantially equal to or higher than that of conventionally commercially available volatile solvent-based adhesives, and it does not contain volatile solvents or separate propellants (e.g., spray gases) such that problems such as fire risk, legal restrictions on storage amounts, toxicity to humans, and environmental load due to the destruction of the ozone layer may not fundamentally occur.

In addition, according to one or more embodiments of the present invention, an aqueous aerosol adhesive composition may increase productivity by improving convenience in work and handling, since it may be sprayed at a predetermined distance without a separate volatile propellant or spray gas. Accordingly, it may be applied not only to spray adhesive applications, but also to various fields.

The effects according to the present invention are not limited by the above exemplified descriptions, and more various effects are included in the present specification. [BRIEF DESCRIPTION OF DRAWINGS]

FIG. 1 is a schematic diagram illustrating a spray container provided with an aerosol adhesive and a process in which the aerosol adhesive is sprayed from the spray container according to an embodiment of the present invention. FIG. 2 is a graph illustrating initial spray ability and re- spray ability using the aerosol adhesives of Examples 1 to 7 and

Comparative Examples 2 and 3; and FIG. 3 is a graph illustrating paper adhesion and wood adhesion using the aerosol adhesives of Examples 1 to 7 and Comparative Examples 2 and 3. [MODES FOR CARRYING OUT THE INVENTION]

Hereinafter, the present invention will be described in detail. However, the present invention is not limited only by the following description, and each element may be variously modified or selectively used as necessary. Accordingly, it should be understood that all changes, equivalents, and substitutes are included in the spirit and scope of the present invention.

As used herein, the term "composition" includes mixtures of materials including the composition, as well as reaction products 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, whether of the same kind or different kinds. Accordingly, the term "polymer" used herein includes both of a homopolymer (used to refer to a polymer made from only one kind of monomer with the understanding that trace impurities may be incorporated into the polymer structure), and a copolymer to be defined below. In an example, the polymer may optionally include a polymer made from one or more different monomers, such as copolymers, terpolymers, tetrapolymers, pentapolymers, etc., and may mean any of random, block, graft, sequential, or gradient polymers.

In addition, throughout the present specification, when a certain part "includes (or comprises)" a certain element, it may mean that other elements may be further included, rather than excluding other elements, unless otherwise stated. In addition, the terms of the degree such as 'about' and 'substantially' in the present specification, when manufacturing and material tolerances specific to the meaning are indicated, only mean the numerical value or a value close to the numerical value, and the present invention is not limited to the numerical value.

Unless otherwise stated, all terms (including technical and scientific terms) used in the present specification may be used as meanings that may be commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in a commonly used dictionary are not interpreted ideally or excessively, unless explicitly stated specifically.

In the present specification, a volatile propellant is a term referring to a conventional propellant and/or spray gas used in the aerosol field. Examples thereof may include freon gas, liquefied natural gas (LNG), fluorocarbon (CFC, HCFC, HFC)-based and hydrofluoroalkane (HFA)-based propellants, and more specifically, propane, n-butane, isobutene compounds, chlorofluorocarbons, dimethyl ether, methyl ethyl ether, hydrofluoroalkane (HFA), hydrofluoroolefin, nitrogen, carbon dioxide, etc.

<Aqueous aerosol adhesive composition> An aqueous aerosol adhesive composition according to an embodiment of the present invention includes a vinylacetate- ethylene (VAE)-based emulsion; a surfactant; and a non-volatile (non-VOC) solvent containing water.

In specific, conventional volatile solvent-based spray adhesives have disadvantages such as fire risk, legal restrictions on storage amount, toxicity to humans, and environmental load problems due to ozone layer destruction, and in the case of the aqueous acrylic spray adhesive, there is a problem that a spray gas is indispensably required to secure proper spray ability. On the other hand, the aqueous aerosol adhesive composition according to an embodiment of the present invention may be differentiated from conventional volatile solvent-type adhesives and aqueous aerosol adhesives in that it is applicable in the form of an aerosol without the use of a harmful propellant and/or a spray gas (e.g., dispersible gas). Such an aqueous aerosol adhesive composition may be sprayed through manual pumping, mechanical or compressed air at room temperature when applied to the product and also allow smooth spraying at a predetermined distance, thereby enhancing the convenience and productivity of work.

In addition, the aqueous aerosol adhesive composition is environmentally friendly because it does not use volatile solvents and dispersible gases that cause toxicity and destruction of the ozone layer, and thus the problems of the aforementioned volatile solvent-based spray adhesive and aqueous acrylic spray adhesive may be fundamentally solved. In addition, it is possible to exhibit both adhesion (e.g., adhesiveness) and spray ability substantially equal to or higher than that of conventional commercially available volatile solvent-based spray adhesives.

Hereinafter, composition of the aerosol adhesive composition will be described in detail.

Vinylacetate-ethylene emulsion The aqueous aerosol adhesive composition according to an embodiment of the present invention includes an emulsion containing a vinylacetate-ethylene (VAE) copolymer having excellent adhesion performance and environmental friendliness. Such a VAE copolymer is a binder component included in an aqueous aerosol and exhibits excellent adhesion after being sprayed onto an adherend (substrate).

The vinylacetate-ethylene (VAE) copolymer includes conventional vinylacetate (VA) polymerization units and ethylene

(ethylene) polymerization units known in the art, and any VAE copolymer in which a content of vinylacetate (VA) is more than 50 percent by weight (wt%) with respect to the total weight of the copolymer (or polymer) may be used without limitation.

The polymers are based, in general, on vinylacetate/ethylene (VAE) copolymers having a vinylacetate content of more than 50 percent by weight (wt%), preferably ≥52 wt%, more preferably ≥55 wt%, and an ethylene content of less than 50 wt%, preferably 1 to 40 wt%, and optionally further monomers copolymerizable therewith, in each case with respect to the total weight of the monomer mixture, and the figures in wt% totaling 100 wt% in each case. According to an exemplary embodiment of the present invention, the vinylacetate-ethylene (VAE) copolymer has a vinylacetate (VA) content of more than 50 wt wt% and 99 wt wt% or less; and an ethylene content of 1 wt wt% or more and less than 50 wt wt% with respect to the total weight of the vinylacetate/ethylene (VAE) copolymer.

Suitable further vinyl ester monomers are vinyl higher esters, for example those of carboxylic acids having 3 to 15 C atoms. Suitable further monomers from the group of acrylic esters or methacrylic esters include, for example, esters of unbranched or branched alcohols having 1 to 15 C atoms. Preferred vinylaromatic further monomers are styrene, methylstyrene, and vinyltoluene. A preferred vinyl halide further monomer is vinyl chloride. The preferred olefin further monomers are propylene and butylene, and the preferred dienes are 1,3-butadiene and isoprene.

Optionally, it is also possible for 0.1 to 10 wt% of auxiliary monomers to be copolymerized, with respect to the total weight of the monomer mixture. Preference is given to using 0.1 to 5 wt% of optional auxiliary monomers. Embodiments of optional auxiliary monomers are ethylenically unsaturated monocarboxylic and dicarboxylic acids, ethylenically unsaturated carboxamides and carbonitriles, and also maleic anhydride, and ethylenically unsaturated sulfonic acids and their salts. Other Embodiments of optional auxiliary monomers are precrosslinking comonomers such as polyethylenically unsaturated comonomers, or post crosslinking comonomers, Embodiments being N-methylolacrylamide (NMA), and N- methylolmethacrylamide (NMMA). Also suitable are epoxide- functional comonomers such as glycidyl methacrylate and silicon- functional comonomers, such methacryloyloxypropyltrialkoxysilanes, and vinyltrialkoxysilanes.

Preference is given to copolymers of 60 to 99 wt% of vinylacetate with 1 to 40 wt% of ethylene; Copolymers of more than 50 wt% of vinylacetate with 1 to 40 wt% of ethylene and one or more further comonomers from the group of the vinyl esters having 1 to 12 carbon atoms in the carboxyl radical, such as vinyl propionate, vinyl laurate, and vinyl esters of alpha-branched carboxylic acids having 5 to 12 carbon atoms, such as VeoVa9® and VeoValO®;

Copolymers of more than 50 wt% of vinylacetate, 1 to 40 wt% of ethylene and one or more further comonomers from the group of (meth)acrylic esters of unbranched or branched alcohols having 1 to 15 carbon atoms, especially methyl methacrylate, methyl acrylate, n-butyl acrylate and 2-ethylhexyl acrylate; where the copolymers may each also contain the auxiliary monomers mentioned in the amounts mentioned, and the figures in wt% total 100 wt% in each case.

The monomer selection and the selection of the weight fractions of the comonomers are preferably selected so as to result in glass transition temperatures, Tg, ranging from -40°C. to +35°C., more preferably -40°C. to +20°C., and most preferably -20°C. to +20°C. The Tg of the polymers may be determined in a known way by means of Differential Scanning calorimetry (DSC, DIN EN ISO 11357-1/2), for example determined with a calorimeter DSC from Mettler-Toledo, with a heating rate of 10 K/min as midpoint temperature. The Tg may also be calculated approximately in advance using the Fox equation. According to Fox T. G., Bull. Am. Physics Soc. 1, 3, page 123 (1956) the following is the case

: 1/Tg=x1/Tg1+x2/Tg2+ . . +xn/Tgn, where xn stands for the mass fraction (wt %/100) of the monomer n, and Tgn is the glass transition temperature, in degrees Kelvin, of the homopolymer of the monomer n. Tg values for homopolymers are listed in Polymer Handbook 2nd Edition, J. Wiley & Sons, New York (1975).

The polymers are prepared generally in an aqueous medium and preferably by the emulsion or suspension polymerization process, as described for example in WO 2010/057888 A1. The polymers in that case are obtained in the form of aqueous dispersions. In the polymerization, it is possible to use the customary protective colloids and/or emulsifiers, as described in WO 2010/057888 A1.

As protective colloids preference is given to partially hydrolyzed or fully hydrolyzed polyvinyl alcohols, having a degree of hydrolysis of 80 to 100 mol- %, more particularly to partially hydrolyzed polyvinyl alcohols having a degree of hydrolysis of 80 to 94 mol- % and a Höppler viscosity, in 4 % strength aqueous solution, of 1 to 30 mPas (Hbppler method at 20°C., DIN 53015). The stated protective colloids may be obtained by methods known to the skilled person and are added generally in an amount of in total 1 to 20 wt%, with respect to the total weight of the monomers, in the polymerization.

The polymers in the form of aqueous dispersions will be dried in a conventional manner. In a preferred embodiment the polymers may be converted to water-dispersible polymer powders by the spray- drying process, as described in WO 2010/057888 A1, for example.

In that case it is usual to add a drying aid in a total amount of

3 to 30 wt%, based on the polymeric constituents of the dispersion. Preferred drying aids are the abovementioned polyvinyl alcohols. Additionally, anti-blocking agent may be added during or after the drying step.

The polymer powders are commercially available, for example as Vinnapas® and ETONIS® dispersion powders of Wacker Chemie AG.

The vinylacetate/ethylene polymers may also be prepared by other methods, including solution polymerization, or bulk (neat) polymerization. Polymers prepared by solution or bulk polymerization are preferably supplied in a form having a relatively high surface area. For this purpose, for example, the polymers may be extruded into pellets or granules by conventional processes or otherwise prepared in small particle sizes. The use of water-dispersible powders resulting from emulsion or suspension polymerization followed by drying, in particular, spray drying, reduces asphalt blending time significantly, and thus water dispersible powders are highly preferred.

In an embodiment, the vinylacetate-ethylene emulsion containing the VAE-based polymer has a solid content of 5 wt% or more, a viscosity in a range from 10 to 10,000 ops at 25°C; and a pH in a range from 2.0 to 10.0. More specifically, the solid content may be in a range from 10 to 75 wt%, the viscosity may be in a range from 20 to 9,000 ops with respect to 25°C, and the pH may be in a range from 3.0 to 10.0. When the VAE emulsion has all the above-described solid content, viscosity and pH properties, it is possible to manufacture a product that may be sprayed in the form of an aerosol.

In order to further improve the adhesion of the adhesive composition, the present invention may mix at least one kind of VAE copolymer or VAE copolymer-containing emulsion having different glass transition temperatures (Tg). That is, when the glass transition temperature (Tg) of the polymer is low, it has tacky properties, thereby increasing interfacial adhesion with other substrates and improving fluidity. On the other hand, when the content is increased beyond a predetermined range, internal cohesion of the VAE copolymer binder itself may decrease. In the present invention, by using at least two kinds of VAE copolymers or VAE emulsions having different glass transition temperatures (Tg) in a predetermined ratio, it is possible to secure high internal cohesion of the adhesive itself, while maintaining interfacial adhesion and fluidity.

In an embodiment, the vinylacetate-ethylene (VAE) copolymer may use at least one VAE copolymer having a glass transition temperature (Tg) in a range from -40°C to 35°C, and more specifically, may include a first VAE copolymer having a glass transition temperature (Tg) of -40°C or more and less than 0°C; and a second VAE copolymer having a glass transition temperature (Tg) in a range from 0°C to 35°C. Herein, the first VAE copolymer having a low Tg may exhibit an effect of improving initial tackiness to the adherend surface.

In such an embodiment, a mixing ratio of the first copolymer and the second copolymer is not particularly limited and may be appropriately adjusted in consideration of adhesion and fluidity. As an example, the mixing ratio of the first copolymer and the second copolymer may be in a range from 1 : 1 to 50 : 1 by weight, specifically 1 : 1 to 20 : 1 by weight, and more specifically 5 : 1 to 15 : 1 by weight. In the aqueous aerosol adhesive composition according to an embodiment of the present invention, the content of the VAE-based emulsion is not particularly limited, and as an example, it may be in a range from 10 to 90 wt%, and specifically 20 to 85 wt%, with respect to the total weight (e.g., 100 wt%) of the adhesive composition. When the content of the VAE-based emulsion is within the above numerical range, excellent adhesion, fluidity, and workability may be exhibited without deteriorating physical properties.

Surfactants The aqueous aerosol adhesive composition according to an embodiment of the present invention includes a surfactant.

The surfactant helps uniform and stable dispersion between raw materials in the process of mixing (e.g., blending) with other raw materials, and serves to improve storage stability and workability. In addition, since the surfactant adsorbs or surrounds on surfaces of the raw materials, re-aggregation is substantially prevented by maintaining a constant gap between the raw materials due to, for example, electrostatic repulsion or steric hindrance effect.

As the surfactant, a surfactant or dispersion stabilizer known in the art may be used without limitation, and for example, may include at least one of an anionic surfactant, a cationic surfactant, and a non-ionic surfactant. Non-limiting examples of the applicable surfactants may include sodium polyacrylate, saponification products of styrene (or olefin) maleic anhydride copolymer, sodium alkylnaphthalene sulfonic acid-formalin condensate, sodium lignin sulfonic acid, polyethylene glycol phenyl ether, polyethylene glycol higher alkyl, ether dialkyl sulfosuccinate, alkyl amine, alcohol amine, polycarboxylic acid, polyethyleneimine, sorbitan aliphatic ethylene oxide adduct, or mixtures thereof. Specifically, a polycarboxylic acid-type surfactant may be used.

In the aqueous aerosol adhesive composition according to an embodiment of the present invention, a content of the surfactant is not particularly limited, and for example, it may be in a range from 0.1 to 10 wt%, and specifically 0.5 to 9 wt%, with respect to the total weight (e.g., 100 wt%) of the adhesive composition. When the content of the surfactant is within the above-described numerical range, excellent dispersibility and workability may be exhibited without deteriorating physical properties.

Non-volatile solvent

The aqueous aerosol adhesive composition according to an embodiment of the present invention includes a conventional non- volatile (non-VOC) solvent known in the art.

In the present invention, the use of a volatile solvent known in the art, that is, an organic compound (VOC) having a sufficient vapor pressure to be vaporized under conventional conditions, is excluded.

The applicable non-VOC solvent is not particularly limited, and for example, water may be used alone or a mixture of water and alcohol may be used. Water is not particularly limited, and as an example, a distilled water or tap water may be used. And alcohol is not particularly limited, and as an example, lower alcohols having 1 to 6 C atoms may be used.

In addition, when a mixture of water and alcohol is used, a mixing ratio of water and alcohol may be appropriately adjusted in consideration of spray ability of the aqueous aerosol adhesive composition. For example, the mixing ratio of water and alcohol may be in a range from 1 : 0.1 to 1 : 50.0 by weight, specifically

1 : 0.5 to 1 : 20.0 by weight, and more specifically 1 : 0.5 to 1

: 10.0 by weight. In the aqueous aerosol adhesive composition according to an embodiment of the present invention, a content of the non-volatile solvent is not particularly limited, and may be, for example, a remaining amount that satisfies the total weight (e.g., 100 wt%) of the adhesive composition. For example, it may be in a range from 5 to 80 wt% with respect to the total weight of the adhesive composition.

Acrylic polymer

The aqueous aerosol adhesive composition according to an embodiment of the present invention may further include an acrylic polymer.

Such an acrylic polymer may be added for the purpose of enhancing adhesion of the adhesive composition, and a conventional (meth) acrylic polymer known in the art may be used without limitation.

Non-limiting examples of applicable acrylic polymers may include at least one of Ethyl acrylate, 2-hydroxyethyl acrylate, and butyl acrylate. A content of the acrylic polymer is not particularly limited, and as an example, may be in a range from 0.1 to 10 wt% with respect to the total weight (e.g., 100 wt%) of the adhesive composition.

Tackifier The aqueous aerosol adhesive composition according to an embodiment of the present invention may further include a conventional tackifier known in the art.

The tackifier is a material that is added to improve initial adhesion between objects to be bonded and/or improve adhesion persistence, and an adhesion promoter or a tackiness promoter known in the art may be used without limitation.

Applicable examples of the tackifier may include rosin and derivatives thereof (e.g., rosin esters); terpenes and modified terpene resins; aliphatic, alicyclic and aromatic resins; hydrogenated hydrocarbon resins and mixtures thereof; terpene- phenol resins, polyethyleneimines, novolacs, or mixtures thereof. Specific examples thereof may include rosin, rosin ester resins, polyterpene and aromatic modified polyterpene resins, coumarone indene resins, hydrocarbon resins (e.g., α-pinene resins, β-pinene resins, limonene resins, aliphatic hydrocarbon resins, aromatic modified hydrocarbon resins); or a combination thereof.

In an embodiment of the present invention, an amount of the tackifier is not particularly limited, and may be in a range from 0.1 to 10 wt% with respect to the total weight (e.g., 100 wt%) of the adhesive composition.

Additive

In addition to the above-described components, the aerosol adhesive composition according to an embodiment of the present invention may use at least one additive known in the art without limitation, within a range that does not impair the effect of the present invention.

Non-limiting examples of the applicable additives may include defoaming agents, plasticizers, stabilizers, dispersants, corrosion inhibitors, pigments, dyes, diluents, viscosity modifiers, thickeners, and the like. These may be used solely or may be used in combination of two or more. A content of the additive is not particularly limited, and may be appropriately adjusted within a content range known in the art. For example, the at least one additive may be included in an amount ranging from 0.01 to 10 wt%, and specifically 0.03 to 5 wt%, with respect to the total weight of the adhesive composition.

As the plasticizer, a conventional plasticizer component known in the art may be used without limitation. For example, hydrocarbon oil (e.g. aromatic, paraffinic or naphthenic), hydrocarbon resins, polyterpene, rosin ester, phthalate (e.g. terephthalate), phosphoric ester, dibasic acid ester, fatty acid ester, polyether (e.g. alkylphenyl ether), epoxy resins, sebacate, adipate, citrate, trimellitate, dibenzoate, or combinations thereof.

In addition, the corrosion inhibitor is a material capable of substantially preventing a chemical reaction between the composition and a metal constituting a container. Non-limiting examples of the applicable 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.

In addition, examples of antioxidants may include phenol, phosphite, thioester, amine, high molecular-hindered phenol, copolymers of 4-ethyl phenol, reaction products of dicyclopentadiene and butylene, or a combination thereof. The aerosol adhesive composition according to an embodiment of the present invention may be prepared by blending (e.g., mixing) the aforementioned VAE emulsion, the surfactant, the non-volatile solvent, and other additives such as acrylic polymers, emulsifiers, tackifiers, defoaming agents, plasticizers, etc., as required, and then mixing and stirring the blended mixture according to a conventional method known in the art until the VAE- based copolymer contained in the VAE emulsion is properly dispersed. If necessary, other additives or solvents may be further added. The mixing method is not particularly limited, and as an example, a mixer such as a conventional mixing mixer, homogenizer, homo disper, homo mixer, universal mixer, planetary mixer, or kneader known in the art may be used. In addition, as an example of the mixing condition, it may be carried out at a speed of 1000 rpm or less under a temperature condition in a range from 10 to 90 °C for 1 to 3 hours, and specifically, at a speed in a range from 200 to 800 rpm at a temperature in a range from 10 to 70 °C. In such an embodiment, the emulsion system may be broken during long- term stirring at a stirring speed exceeding 1000 rpm, and long- term heating at a temperature exceeding 90°C may affect the physical properties, and accordingly, it is desirable to carefully mix under the aforementioned mixing conditions.

When the prepared mixture is exposed to air, curing may proceed, and accordingly, before using the aerosol adhesive composition, it may be stored in a storage tank or spray container with limited exposure to air. Accordingly, in an embodiment of the present invention, the prepared mixture may be transferred to a sealed storage tank or spray container so as not to be cured by exposure to air, and then sealed according to a conventional method known in the art to manufacture a final product.

In an embodiment, the aerosol adhesive composition of the present invention may include, with respect to the total weight (e.g., 100 wt%) of the composition, the vinylacetate-ethylene (VAE) emulsion in a range from 10 to 90.0 wt%; the surfactant in a range from 0.1 to 10 wt%; and the non-volatile solvent with the remaining amount to satisfy 100 wt% of the composition. In such an embodiment, a content of the non-volatile solvent containing water is not particularly limited, and may be, for example, in a range from 5 to 80 wt%. If necessary, additives or solvents in the art may be additionally included, and a content thereof may be a remaining amount satisfying the total weight (e.g., 100 wt%) of the composition. In an embodiment, the aerosol adhesive composition may have a viscosity in a range from 10 to 10,000 ops, and specifically 20 to 9,000 ops, at 25°C. In addition, a solid content may be in a range from 10 to 80 wt%, and specifically 10 to 70 wt%.

The aerosol adhesive composition according to an embodiment of the present invention constituted as described above may satisfy the required properties (e.g., adhesion, spray ability, etc.) as an aerosol adhesive, and may secure convenience in workability and productivity, even though it does not contain harmful volatile propellants or spray gases. In particular, dissimilar to the conventional aqueous acrylic adhesives, it is possible to spray by conventional spraying methods known in the art, such as manual pumping, mechanical or compressed air. In such a case, the internal pressure of the container containing the aerosol adhesive composition is not particularly limited as long as it may be sprayed. For example, in the case of mechanical or compressed air, it may be 10 bar or less, and specifically in a range from 0.5 to 9.0 bar, at room temperature.

In addition, since the aerosol adhesive composition may be smoothly sprayed at a predetermined distance, there is an advantage that productivity may be improved by improving the convenience of work and handling. In such an embodiment, the spacing distance to allow spraying is not particularly limited, and may be, for example, in a range from 1 to 150 cm. In an embodiment, the aerosol adhesive composition may satisfy at least one physical property of the following (i) to (iv), and specifically, may satisfy two or more, and more specifically, all of (i) to (iv). For example, (i) a spray diameter according to the ASTM D4041 standard is 3.5 cm or more, (ii) a re-spray diameter after 10 days is 3.5 cm or more, (iii) an adhesion with paper according to the Pappi test is 2.5 or more, and (iv) a maximum adhesion force (e.g., adhesiveness) to wood according to the DIN EN 204/DIN EN 205 may exceed 0.5 kgf.

In the present invention, temporary securing or high- performance use (high adhesion) may be implemented by controlling the components constituting the aerosol adhesive composition and its composition.

As an embodiment of the aerosol adhesive composition for temporary securing, (i) the spray diameter according to the ASTM D4041 standard may be 3.5 cm or more, and specifically in a range from 3.5 to 5.0 cm, (ii) the re-spray diameter after 10 days may be 3.5 cm or more, and specifically in a range from 3.5 to 5.0 cm,

(iii) the adhesion with paper according to the Pappi test may be

2.5 or more, and specifically in a range from 2.5 to 4.0, and (iv) the maximum adhesion force with wood according to the DIN EN 204/DIN EN 205 may exceed 0.5 kgf, and specifically in a range from 1.0 to 6.0 kgf.

In addition, as an embodiment of the aerosol adhesive composition for high-performance use, (i) the spray diameter according to the ASTM D4041 standard may be 3.5 cm or more, and specifically in a range from 3.5 to 5.0 cm, (ii) the re-spray diameter after 10 days may be 3.5 cm or more, and specifically in a range from 3.5 to 5.0 cm, (iii) the adhesion with paper according to the Pappi test may be 4.0 or more, and specifically in a range from 4.0 to 5.0, and (iv) the maximum adhesion force (e.g., adhesion) to wood according to the DIN EN 204/DIN EN 205 may exceed 5.5 kgf, and specifically in a range from 7.5 to 30.0 kgf.

The aqueous aerosol adhesive composition according to an embodiment of the present invention may be accommodated (e.g., contained) in conventional aerosol devices known in the art.

Such an aerosol delivery device is not particularly limited, and may be, for example, a conventional accommodating container known in the art having a valve and/or a spray device. Referring to FIG. 1, the aerosol device may include: a container 1 accommodating an aqueous aerosol adhesive composition 2; a nozzle for spraying the composition 2 in the form of an aerosol 5; and a hose 3 provided between the container 1 and the nozzle to supply the adhesive composition 2 from the container 1 to the nozzle. In addition, a suction pump may further be included.

In order to effectively spray the aerosol adhesive composition accommodated in the accommodating container, a propellant and/or a spray gas may be further included. Such propellants and/or spray gases excludes conventional propellants or spray gases having harmfulness, may use at least one or more of carbon dioxide, nitrogen, compressed air typically known in the art, and may have an internal pressure of 10 bar or less at room temperature before spraying.

The aqueous aerosol adhesive composition according to an embodiment of the present invention may be applied to a substrate having various materials and/or shapes, thereby exhibiting excellent adhesion. The substrate is not particularly limited as long as it is a material capable of being sprayed with and applied by an aqueous aerosol adhesive to adhere to other substrates. For example, it may be applied to at least one substrate selected from the group consisting of paper, wood, metal, steel plate, film, tile, plastic, glass, resin, ceramic, concrete, carbon material, fiber, and composite materials thereof.

Since the aerosol adhesive composition according to an embodiment of the present invention as described above not only secures excellent adhesion and spray ability, but also has eco- friendliness, it may be usefully used as a spray-type adhesive and may be applied to various fields without limitation.

Hereinafter, the present invention will be described in detail through examples. However, the following examples are merely illustrative of the present invention, and the present invention is not limited by the following examples.

[Reference Example]

The vinylacetate-ethylene-based emulsion (VAE dispersion) used in the following Examples and Experimental Examples uses a VINNAPAS dispersion product of WACKER Chemical. In addition, a distilled water was used as water.

[Examples 1 to 7: Preparation of aerosol adhesive composition]

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

(Note) 1) First VAE copolymer: VINNAPAS EAF7012 [Tg: -14 ~ - 16°C, Viscosity: 100~500 ops (at 25°C), pH: 6~8, Solid content: 54~56 wt%] 2) Second VAE copolymer: VINNAPAS EP3360 [Tg: 5~7°C,

Viscosity: 3,000~8,000 ops (at 25°C), pH: 5~6, Solid content: 59~62 wt%]

[Experimental Example: Physical property evaluation of aerosol adhesive composition]

In order to identify applicability of the aqueous VAE (Vinylacetate-ethylene)-based aerosol adhesive composition according to an embodiment of the present invention, spray ability adhesion with paper (e.g., paper tear adhesion), and adhesion with wood are evaluated as compared to conventional volatile solvent- based spray adhesives.

As an example, as illustrated in Fig. 1, the aerosol adhesive compositions 2 prepared in Examples 1 to 7 were each put into the accommodating container 1, the aerosol adhesive 2 was sprayed from the accommodating container 1 onto the substrate 6, and then physical properties of the applied adhesive 7 were evaluated by the test methods shown in Table 2 below. The results are shown in Table 3 and FIGS. 2 to 3, respectively. As a control group, general tap water was used in Comparative Example 1, and typical volatile solvent-based spray adhesives were used in Comparative Examples 2 and 3, respectively.

<Physical property evaluation method> (1) Evaluation of spray ability of adhesive (initial spray ability)

Specifically, after filling the aqueous vinylacetate- ethylene (VAE) aerosol adhesive composition prepared in Examples 1 to 7 into a spray container, the adhesive was sprayed by manually (e.g., by human hand) operating, for about three minutes, a lever of a sprayer having a discharge port diameter of 0.2 mm horizontally at a height of about 10.2 cm (= 4 inch) from an A4- sized paper which is an adherend surface, according to the test conditions in Table 2 below according to the ASTM D4041-05 "Standard Practice for Determining Spray Patterns of Mechanical Pump Dispensers", thereby spraying the adhesive. In such a case, the adhesive was sprayed in the form of an aerosol and applied to the paper, which is an adherend, in the shape of a circle or oval, depending on the size and shape of the spray equipment tip. In order to evaluate the spray ability, the lengths in the X-axis and Y-axis of the adhesive sprayed onto the paper, which is the adherend, were measured after spraying. As a control group, water containing no adhesive (Comparative Example 1) and volatile solvent-based spray adhesives (Comparative Examples 2 to 3) were used to evaluate the spray pattern and spray ability in a relative manner. Herein, the general tap water used as Comparative Example 1 exhibited a constant circular shape after spraying, and its X- axis and Y-axis length (diameter) averaged about 5 cm. (2) Evaluation of re-spray ability of adhesive

After 10 days have elapsed after the above initial spraying experiment was carried out, spray pattern and spray ability were evaluated in a relative manner by re-spraying the aqueous VAE (Vinylacetate-ethylene) aerosol adhesive composition of Examples 1 to 7 according to the ASTM D4041-05 "Standard Practice for

Determining Spray Patterns of Mechanical Pump Dispensers". As a control group, volatile solvent-based spray adhesives (Comparative

Examples 2 to 3) were used. (3) Evaluation of adhesion with paper

The experiment was conducted in the same manner as the Tappi test. Specifically, a paper was cut into a size of 22 cm (length) x 10 cm (width) in a large area, and then the center was folded so that the top and bottom size was 11 cm (length) x 10 cm (width).

To prevent complete adhesion, about 1 cm of each top and bottom end was folded outward, and then an aerosol adhesive (spray adhesive) was evenly sprayed to 10 cm (length) x 10 cm (width) on one side to apply the adhesive and dried for about 10 minutes after evenly stacking the top and bottom. Then, opposite sides to which the adhesive was not applied were pulled to check the tearing of the bottom paper, and then the level of a remaining portion with respect to the total area was recorded. In such a case, the evaluation of the adhesion level between paper and paper was evaluated as 5 when an adhesive area was about 100 cm ² , 4 when 80 cm ² , 3 when 60 cm ² , 2 when 40 cm ² , 1 when 20 cm ² , and 0 when 0 cm ² .

(4) Evaluation of adhesion with wood

After filling the aqueous aerosol adhesive composition prepared in Examples 1 to 7 into a spray container, it was sprayed onto a wood specimen according to the 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", thereby evaluating adhesion. In such a case, a maximum load was recorded for the results of the adhesion test with wood.

[Table 2]

[Table 3]

Herein, the index of spray ability was evaluated through an

X-axis average length (diameter) of an adhesive-applied surface formed after spraying, and the index of adhesion with paper was evaluated through the adhesion area of the adhesive formed after spraying. In addition, the index of adhesion with wood was evaluated by the maximum load of the adherend after spraying. It was appreciated that the spray ability (spraying property) was improved, while the adhesion area decreases in the adhesion with paper test (Tappi test), as a content of the VAE emulsion decreases, and as a content of ethanol and water increases in the mixing ratio of the aerosol adhesive composition according to an embodiment of the present invention. Accordingly, in an embodiment of the present invention, it was found that spray ability, adhesion with paper, and the like may be controlled through adjustment of the mixing ratio of the aerosol adhesive composition.

As shown in Table 3, in the case of Comparative Example 2 (3M company, graphic art 75 spray, for temporary securing), which is a representative volatile solvent-based spray adhesive, the initial spray ability and re-spray ability were each 3.8 cm, the adhesion with paper was 3 cm, and the maximum adhesion force with wood was 1.2 kgf. On the other hand, in the case of the aqueous VAE aerosol adhesive of Example 2 of the present invention, the initial spray ability and re-spray ability were each 3.8 cm, the adhesion with paper was 2.8 cm, and the maximum adhesion force with wood was 4.7 kgf, exhibiting spray ability and adhesion length to paper substantially equal to or higher than those of Comparative Example 2. In particular, in terms of adhesion with wood, it was appreciated that the adhesive of Example 2 exceeded 3.5 kgf as compared to Comparative Example 2, which is a volatile solvent- based spray adhesive, which is about 3 times improvement. In addition, in the case of Comparative Example 3 (3M company, high strength 99 spray, for high performance), which is another volatile solvent-based spray adhesive, the initial spray ability and re-spray ability were each 4.0 cm, the adhesion with paper was 4.8 cm, and the adhesion with wood was 7.6 kgf. On the other hand, the aqueous VAE aerosol adhesives of Examples 3 to 7 of the present invention showed the initial spray ability, the re- spray ability, the adhesion with paper, and the adhesion with wood substantially equal to or higher than those of Comparative Example 3. Specifically, in the case of Examples 4 and 7, the spray ability was 4.5 cm or more, the adhesion with paper was 4.8 cm or more, and the maximum adhesion force with wood was 9.1 kgf and 11.6 kgf, respectively, which is equal to or higher than those of the high-performance volatile spray adhesive currently available on the market. In particular, in terms of adhesion with wood, Example 4 showed 9.1 kgf, exhibiting an improvement effect of about

20 % or more as compared to Comparative Example 3 (3M company, high strength 99 spray, for high performance), and Example 7 showed

11.6 kgf, exhibiting an improvement effect of about 53 % or more as compared to Comparative Example 3. Meanwhile, in the case of Example 6 in which a tackifier was included in a predetermined amount, viscosity and tackiness (e.g., stickiness) of the aerosol adhesive composition increased, and an initial spray diameter and an applicable area during re-spraying decreased. As described above, it was found that the spray ability and adhesion of the aerosol adhesive composition may be controlled by controlling the content of the tackifier.

Based on the above results, the aqueous VAE aerosol adhesive according to an embodiment of the present invention is not only eco-friendly because it does not use a volatile solvent (VOC) or a separate propellant, but also achieves the required properties as an adhesive that are equal to or higher than those of the conventional volatile solvent spray adhesive, and accordingly, it was appreciated that it may be usefully applied as an eco-friendly aerosol adhesive.

[Reference signs]

1. Spray Adhesive Container

2. Adhesive 3. Inlet

4. Spray head with comprising spray vale or comprising button

5. Aerosol adhesive

6. Substrate

7. Applied adhesive