Aqueous flame-retardant adhesive composition and method for its preparation

Abstract

The present invention relates to an aqueous flame-retardant adhesive composition, which is environmentally friendly, can reduce costs by replacing organic flame retardants, improves layer separation of the adhesive caused by the addition of inorganic flame retardants, and has excellent adhesive strength, low-temperature stability, processability, and resistance to extraction, and a method for preparing the same.

Description

TECHNICAL FIELD

[0001] Cross Reference to Related Applications

[0002] This application claims the benefit of Korean Patent Application No. 10-2020-0186088, filed December 29, 2020, the disclosure of which is incorporated herein in its entirety by reference.

[0003] The present invention relates to a water-based flame-retardant adhesive composition and a method for preparing the same, and more particularly, to a water-based flame-retardant adhesive composition, which is environmentally friendly, reduces costs by replacing organic flame retardants, improves layer separation of an adhesive caused by the addition of inorganic flame retardants, and has excellent adhesive strength, low-temperature stability, processability, and extraction resistance, and a method for preparing the same. BACKGROUND

[0004] Most of the adhesives used at present are adhesives using organic solvents. However, as internal and external environmental regulations are strengthened and the demand for clean work environments increases, and due to the advantages in cost reduction and productivity improvement, the demand for water-dispersible adhesives is expanding.

[0005] If the existing organic solvent-based adhesives are replaced with water-based adhesives, since water is used as a continuous medium, usability can be improved due to ease of mixing and handling and cost reduction, and cleaning of the work environment and post-processing procedures can be omitted.

[0006] As water-based adhesives, adhesives based on chloroprene latex in the form of a polymer emulsion, a vinyl chloride emulsion, a vinylidene chloride emulsion, a vinyl chloride-acrylate copolymer emulsion, or a vinyl chloride-ethylene-vinyl acetate copolymer emulsion, etc. are being proposed. However, in the case of using these polymer emulsions alone, it can be difficult to achieve flame retardancy.

[0007] Therefore, in order to achieve flame retardancy, methods of using organic or inorganic flame retardants are proposed. Organic flame retardants are mainly classified into non-halogen-based flame retardants such as phosphorus-based, nitrogen-based, etc., and halogen-based flame retardants such as bromine-based, chlorine-based, etc., and inorganic flame retardants are mainly classified into metal hydroxide-based such as aluminum hydroxide, magnesium hydroxide, etc., and antimony-based.

[0008] Although organic flame retardants have excellent flame-retardant effects, they are expensive, and some organic flame retardants, particularly bromine-based flame retardants, generate dioxins when burned, which are harmful to the human body. Also, since inorganic flame retardants should be used in excess, over time, it can be separated or precipitated, so that work cannot be performed, or an additional mixing process is required. SUMMARY

[0009] [TECHNICAL PROBLEM]

[0010] To solve the above problems, according to the present application, there is provided a water-based flame-retardant adhesive composition, which is environmentally friendly, reduces costs by replacing organic flame retardants, improves layer separation of an adhesive caused by the addition of inorganic flame retardants, and has excellent adhesive strength, low-temperature stability, processability, and extraction resistance, and a method for preparing the same.

[0011] [TECHNICAL SOLUTION]

[0012] To achieve this object, according to the present application, there is provided a water-based flame-retardant adhesive composition, which comprises: a base resin selected from the group consisting of a vinyl acetate-ethylene copolymer, an acrylic-based resin, a polyurethane-based resin, and a silicon-based resin; a water-based polyvinyl chloride emulsion; a cyclohexane-based plasticizer; and a benzoate-based plasticizer.

[0013] According to the present application, there is also provided a method for preparing the water-based flame-retardant adhesive composition, comprising the steps of: performing emulsion polymerization or seed emulsion polymerization of a vinyl chloride monomer alone or a mixture of a vinyl chloride monomer and a comonomer copolymerizable therewith in an aqueous medium to prepare a water-based polyvinyl chloride emulsion in which polyvinyl chloride is dispersed in the aqueous medium; and mixing the water-based polyvinyl chloride emulsion with a base resin selected from the group consisting of a vinyl acetate-ethylene copolymer, an acrylic-based resin, a polyurethane-based resin, and a silicon-based resin, and adding and mixing a cyclohexane-based plasticizer and a benzoate-based plasticizer.

[0014] According to the present application, there is also provided an article comprising the water-based flame-retardant adhesive composition.

[0015] [ADVANTAGEOUS EFFECTS]

[0016] The water-based flame-retardant adhesive composition of the present application is environmentally friendly, reduces costs by replacing organic flame retardants, improves layer separation of an adhesive caused by the addition of inorganic flame retardants, and has excellent adhesive strength and low-temperature stability, and has improved processability and extraction resistance. Accordingly, the adhesive composition can be applied to various fields, such as construction, various industries, etc., and in particular, it can be usefully applied to construction / industrial adhesives, adhesive films, decorative sheets, flooring materials, artificial leather, or toys. DETAILED DESCRIPTION

[0017] The terms used herein are used only to explain specific embodiments, and are not intended to limit the present application. Singular expressions include their plural expressions unless explicitly stated or clearly apparent from the context that they are not intended to do so.

[0018] While various modifications can be suggested by those skilled in the art, and it is intended that the present application encompass all such modifications, the specific examples will be illustrated and described in detail herein. It is also understood that this application is not intended to be limited to the particular examples disclosed, but it is intended to cover all modifications and equivalents falling within the spirit and technical scope of the present application.

[0019] Hereinafter, the aqueous flame-retardant adhesive composition and the method for preparing the same according to the present application will be explained in detail.

[0020] The present inventors confirmed that, in preparing the aqueous adhesive composition, when an aqueous polyvinyl chloride-based emulsion is mixed with a base resin, even if a flame retardant is not used or the amount thereof is reduced, excellent flame retardancy can be shown, in addition, by using an environmentally friendly cyclohexane dicarboxylate-based plasticizer as a processing aid, the adhesion strength can be improved, and by using a benzoate-based plasticizer, the processability and the resistance to extraction can be improved, thereby completing the present application.

[0021] Specifically, the aqueous flame-retardant adhesive composition according to the present application comprises

[0022] a base resin selected from the group consisting of a vinyl acetate-ethylene copolymer, an acrylic-based resin, a polyurethane-based resin, and a silicon-based resin;

[0023] an aqueous polyvinyl chloride emulsion;

[0024] a cyclohexane-based plasticizer; and

[0025] a benzoate-based plasticizer.

[0026] In the aqueous flame-retardant adhesive composition, the base resin can be a vinyl acetate-ethylene (VAE) copolymer, an acrylic-based resin, a rubber-based resin, a polyurethane-based resin, or a silicon-based resin, etc. These base resins are environmentally friendly compared to existing synthetic rubber latexes used in adhesive compositions, since they do not use a bromine-based flame retardant.

[0027] Among the base resins, a vinyl acetate-ethylene (VAE) copolymer, which has excellent adhesion and excellent compatibility with the aqueous polyvinyl chloride emulsion, can be preferred.

[0028] Also, the base resin can be an aqueous medium, particularly an aqueous emulsion in which base resin particles are dispersed in water. Among them, it is preferred that the average particle diameter of the base resin is 100 nm to 1.5 μm, more specifically 500 nm to 1.2 μm. If the average particle diameter is less than 100 nm, the particle stability can be deteriorated, and if the average particle diameter is greater than 1.5 μm, the cohesion of the particles after drying can be reduced, thus the adhesion can be deteriorated.

[0029] The base resin can have a weight average molecular weight of 100,000 g / mol or more and 700,000 g / mol or less. If the weight average molecular weight is less than 100,000 g / mol, there is a concern that durability can be reduced due to a decrease in cohesive force, and if the weight average molecular weight is greater than 700,000 g / mol, adhesion or coatability can be deteriorated due to an increase in particle size or viscosity.

[0030] For example, in the case of using a vinyl acetate-ethylene (VAE) copolymer as the base resin, the vinyl acetate-ethylene copolymer can be an emulsion copolymer formed by emulsion polymerization of 10 to 20% by weight of ethylene and 30 to 50% by weight of vinyl acetate with 40 to 60% by weight of polyvinyl alcohol, based on the total weight of the copolymer.

[0031] For example, in the case of using a vinyl acetate-ethylene (VAE) copolymer as the base resin, the vinyl acetate-ethylene copolymer can be an emulsion copolymer formed by emulsion polymerization of 10 to 20% by weight of ethylene and 30 to 50% by weight of vinyl acetate with 40 to 60% by weight of polyvinyl alcohol, based on the total weight of the copolymer.

[0032] The kind of the (meth)acrylate-based monomer is not particularly limited, and for example, an alkyl methacrylate can be used. In this case, if the alkyl group contained in the monomer is too long, the cohesive force of the cured product can be deteriorated, and the glass transition temperature or the adhesion can become difficult to control, and thus an alkyl methacrylate having a carbon number of 1 to 14, preferably 1 to 8, can be used. As examples of these monomers, there can be mentioned methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, sec-butyl methacrylate, amyl methacrylate, 2-ethylhexyl methacrylate, 2-ethylbutyl methacrylate, n-octyl methacrylate, isooctyl methacrylate, isobornyl methacrylate, or isononyl methacrylate, and one or a mixture of two or more of these can be used here.

[0033] Further, the crosslinkable monomer contained in the monomer mixture refers to a monomer that contains both a copolymerizable functional group (for example, a carbon-carbon double bond) and a crosslinkable functional group in the molecular structure, and these monomers can give a crosslinkable functional group to the polymer that is capable of reacting with a polyfunctional crosslinking agent.

[0034] As examples of the crosslinkable monomer, there can be mentioned a hydroxyl group-containing monomer, a carboxyl group-containing monomer, or a nitrogen-containing monomer, and one or a mixture of two or more of these can be used here. In the present disclosure, it is particularly preferable to use a carboxyl group-containing monomer as the crosslinkable monomer, but the crosslinkable monomer is not limited thereto.

[0035] As examples of the hydroxyl group-containing monomer, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, 6-hydroxyhexyl methacrylate, 8-hydroxyoctyl methacrylate, 2-hydroxyethyleneglycol methacrylate, or 2-hydroxypropyleneglycol methacrylate, and the like can be given; as examples of the carboxyl group-containing monomer, acrylic acid, methacrylic acid, 2-methacryloyloxyacetic acid, 3-methacryloyloxypropionic acid, 4-methacryloyloxybutyric acid, acrylic acid dimer, itaconic acid, or maleic acid, and the like can be given; as examples of the nitrogen-containing monomer, 2-isocyanatoethyl methacrylate, 3-isocyanatopropyl methacrylate, 4-isocyanatobutyl methacrylate, methacrylamide, N-vinylpyrrolidone, or N-vinylcaprolactam, and the like can be given, but are not limited thereto.

[0036] The monomer mixture can contain 80 to 99.9% by weight of the methacrylate-based monomer and 0.1 to 20% by weight of the crosslinkable monomer, preferably 90 to 99.9% by weight of the methacrylate-based monomer and 0.1 to 10% by weight of the crosslinkable monomer, based on the total weight of the monomer mixture.

[0037] The method of preparing the base resin containing the above ingredients is not particularly limited, and for example, it can be prepared by a general polymerization method such as solution polymerization, photopolymerization, bulk polymerization, suspension polymerization, or emulsion polymerization. In the present disclosure, it is preferable to prepare a water-dispersed base resin by suspension polymerization or emulsion polymerization, and more preferably by emulsion polymerization.

[0038] Meanwhile, in the aqueous flame-retardant adhesive composition, the aqueous polyvinyl chloride emulsion is a water-dispersed emulsion in which polyvinyl chloride is dispersed in water, and when contained in the adhesive composition, it can exhibit more excellent flame retardancy than other aqueous base resins due to the molecular structure of polyvinyl chloride.

[0039] Throughout the specification, "polyvinyl chloride" means a (co)polymer of only a monomer based on vinyl chloride, or a (co)polymer of a monomer based on vinyl chloride and a comonomer copolymerizable therewith. In addition, it can also be prepared by mixing a suspending agent, a buffer, and a polymerization initiator, etc., by suspension polymerization, micro-suspension polymerization, emulsion polymerization, or mini-emulsion polymerization, etc.

[0040] The comonomer copolymerizable with the vinyl chloride monomer can include, for example, ethylene ester-based monomers including ethylene vinyl acetate monomers and vinyl propionate monomers; olefin-based monomers including ethylene, propylene, isobutyl vinyl ether, and halogenated olefins; methacrylic ester-based monomers including alkyl methacrylate; maleic anhydride monomers; acrylonitrile monomers; styrene monomers; and halogenated polyvinylidene, etc., one or more of which can be mixed to prepare a copolymer with the vinyl chloride monomer. However, the present application is not limited to the above-mentioned monomers, and one or more monomers commonly used in the art to which the present application pertains to form a copolymer through a polymerization reaction with a vinyl chloride monomer can be used without particular limitation according to the desired properties or uses of the aqueous flame-retardant adhesive composition.

[0041] Also, the polyvinyl chloride properties such as the glass transition temperature, the particle size, etc. can be controlled by controlling the polymerization conditions during the polymerization reaction.

[0042] Also, although the glass transition temperature (Tg) of the polyvinyl chloride required can vary depending on the adhesive base, for example, the glass transition temperature (Tg) of the polyvinyl chloride can be -20℃ or more and 80℃ or less.

[0043] In the present disclosure, the glass transition temperature (Tg) of the polyvinyl chloride can be measured using a DSC (Differential Scanning Calorimeter) device.

[0044] Also, the polyvinyl chloride exists as particles dispersed in water, and has an average particle size of 100 nm to 1 μm, more specifically, 100 nm to 0.5 μm. If the average particle size is less than 100 nm, the particle stability can be deteriorated, and thus the dispersibility in the emulsion can be deteriorated due to aggregation between the polyvinyl chloride particles, and if the average particle size is more than 1 μm, the storage stability can be reduced, and the cohesion of the particles after drying can be reduced, and thus the adhesiveness can be deteriorated.

[0045] Meanwhile, in the present disclosure, the average particle size of the polyvinyl chloride and the base resin can be measured according to a commonly used particle size distribution measurement method such as an optical microscope, a light scattering measurement method, etc., and specifically, can be measured using a Zetasizer or a Master Sizer of Malvern Co.

[0046] Also, the polyvinyl chloride can have a weight average molecular weight (Mw) of 45,000 to 300,000 g / mol, more specifically, 50,000 to 130,000 g / mol. In the above weight average molecular weight range, the dispersibility in the emulsion is excellent, thereby improving the mechanical stability. In the present disclosure, the weight average molecular weight of the polyvinyl chloride is a standard polystyrene conversion value of a gel permeation chromatography method.

[0047] Specifically, the weight average molecular weight (Mw) of the polyvinyl chloride and the base resin each refers to a polyvinyl chloride and polystyrene conversion value measured by GPC (gel permeation chromatography). Specifically, the measurement can be performed using a Polymer Laboratories PLgel MIX-B 300 mm column and a Waters PL-GPC220 device, at a measurement temperature of 160°C, using tetrahydrofuran or 1,2,4-trichlorobenzene as a solvent, and at a flow rate of 1 mL / min. The polyvinyl chloride or base resin sample is prepared at a concentration of 10 mg / 10 mL, and then supplied in an amount of 200 μL. The Mw and Mn values are obtained using a calibration curve formed using polyvinyl chloride and polystyrene standards, wherein the molecular weight (g / mol) of the polyvinyl chloride standards is 100,000 to 150,000, and the molecular weight (g / mol) of the polystyrene standards is 190,000.

[0048] The content of the aqueous polyvinyl chloride emulsion solid component can be 10 to 90 parts by weight, based on 100 parts by weight of the base resin solid component. If the content of the aqueous polyvinyl chloride emulsion solid component is less than 10 parts by weight, based on 100 parts by weight of the base resin solid component, there is a concern that the flame retardancy deteriorates, and if it is greater than 90 parts by weight, there is a concern that the adhesion becomes poor. The "aqueous polyvinyl chloride emulsion solid component" refers to all components in the aqueous polyvinyl chloride emulsion except for the aqueous medium, and the "base resin solid component" refers to all components in the base resin except for the aqueous medium.

[0049] The base resin solid component and the aqueous polyvinyl chloride emulsion solid component can be contained in a weight ratio (base resin solid component:aqueous polyvinyl chloride emulsion solid component) of 90:10 to 10:90. Outside of the above mixing weight ratio, if the base resin solid component is less than 10 parts by weight, and the aqueous polyvinyl chloride emulsion is greater than 90 parts by weight, there is a concern that the adhesion deteriorates, and if the base resin solid component is greater than 90 parts by weight, and the aqueous polyvinyl chloride emulsion is less than 10 parts by weight, there is a concern that the flame retardancy deteriorates.

[0050] In consideration of the excellent adhesion and flame retardancy improvement effects by controlling the content ratio of the base resin and the aqueous polyvinyl chloride emulsion, more specifically, the base resin solid component and the aqueous polyvinyl chloride emulsion solid component can be contained in a weight ratio of 60:40 to 90:10, or 70:30 to 85:15.

[0051] In the aqueous flame-retardant adhesive composition, the cyclohexane-based plasticizer can specifically be a cyclohexane dicarboxylic acid ester-based compound containing 2 C 4-10 alkyl groups.

[0052] In the cyclohexane dicarboxylate-based compound, the two alkyl groups can be the same as or different from each other. More specifically, the two alkyl groups can be the same as each other, and they can be C 4-10 alkyl groups, more specifically, the two alkyl groups can be C 4-8 straight-chain alkyl groups such as n-butyl group, and the like; or can be C 6-10 branched-chain alkyl groups such as iso-nonyl group, and the like.

[0053] In the case where the cyclohexane dicarboxylate-based compound is included in the adhesive composition, the Tg can be lowered, and a thickening effect can be provided. Also, due to the excellent frost resistance, the adhesion and the low-temperature stability of the adhesive composition can be improved.

[0054] As more specific examples, cyclohexane-1,2-dicarboxylic acid di(2-ethylhexyl) ester, cyclohexane-1,3-dicarboxylic acid di(2-ethylhexyl) ester, cyclohexane dicarboxylic acid di(2-ethylhexyl) ester (DEHCH), cyclohexane-1,2-dicarboxylic acid diisononyl ester (DINCH), di(2-ethylhexyl)cyclohexane-1,4-diester (DOCH), or cyclohexane-1,4-dicarboxylic acid dibutyl ester (DBCH), and the like can be given, and one or a mixture of two or more kinds thereof can be used. The cyclohexane dicarboxylic acid di(2-ethylhexyl) ester (DEHCH) can be one or more selected from the group consisting of cyclohexane-1,2-dicarboxylic acid di(2-ethylhexyl) ester, cyclohexane-1,3-dicarboxylic acid di(2-ethylhexyl) ester, and cyclohexane-1,4-dicarboxylic acid di(2-ethylhexyl) ester.

[0055] wherein DEHCH is one or more selected from the group consisting of compounds represented by Chemical Formula 1 to Chemical Formula 3, and has an excellent adhesion and low-temperature stability improvement effect, and due to the low viscosity at room temperature and low temperature, excellent coating performance can be achieved. Also, compared to the existing phthalate-based plasticizer, it can minimize the generation of volatile organic compounds.

[0056] [Chemical Formula 1]

[0057]

[0058] [Chemical Formula 2]

[0059]

[0060] [Chemical Formula 3]

[0061]

[0062] The content of the plasticizer based on cyclohexane can be 10 to 30 parts by weight based on 100 parts by weight of the solid content of the base resin. If the content of the plasticizer based on cyclohexane is less than 10 parts by weight based on 100 parts by weight of the solid content of the base resin, the adhesion and low-temperature stability improvement effects by the inclusion of the plasticizer can not be significant, while if it is more than 30 parts by weight, the shear strength of the adhesive can be reduced. In view of the excellent improvement effects by the control of the content, the content of the plasticizer is more preferably 20 to 30 parts by weight based on 100 parts by weight of the solid content of the base resin.

[0063] In the aqueous flame-retardant adhesive composition, the benzoate-based plasticizer can be, for example, one or more selected from the group consisting of sodium benzoate, isononyl benzoate, isodecyl benzoate, 2-propylheptyl benzoate, diethylene glycol dibenzoate, dipropylene glycol dibenzoate, 1,2-dipropylene glycol dibenzoate, and dibutyleneglycol dibenzoate.

[0064] In the case of including the benzoate-based compound in the adhesive composition, with the improvement in the gelling speed, the processability can be improved, and due to the excellent compatibility with the base resin, the resistance to extraction can be improved.

[0065] The content of the benzoate-based plasticizer can be 5 to 30 parts by weight based on 100 parts by weight of the solid content of the base resin. If the content of the benzoate-based plasticizer is less than 5 parts by weight based on 100 parts by weight of the solid content of the base resin, the processability and resistance to extraction improvement effects can not be significant, while if it is more than 30 parts by weight, the viscosity of the composition can increase, and the storage stability can deteriorate.

[0066] Also, the aqueous flame-retardant adhesive composition according to the embodiment of the present application can further include an additive, for example, one or more selected from the group consisting of a crosslinking agent, an initiator, a low-molecular-weight body, an epoxy resin, an ultraviolet stabilizer, an antioxidant, a colorant, a reinforcing agent, an antifoaming agent, a plasticizer, a blowing agent, an organic salt, a thickening agent, and a flame retardant. In the vinyl chloride-based resin composition, the additive can be appropriately selected depending on the property to be improved.

[0067] The aqueous flame-retardant adhesive composition can be prepared by a preparation method including: emulsion polymerization or seed emulsion polymerization of a vinyl chloride monomer alone or a mixture of a vinyl chloride monomer and a comonomer copolymerizable therewith in an aqueous medium to prepare an aqueous polyvinyl chloride emulsion in which polyvinyl chloride is dispersed in the aqueous medium (step 1); and mixing the aqueous polyvinyl chloride emulsion with a base resin selected from the group consisting of a vinyl acetate-ethylene copolymer, an acrylic-based resin, a polyurethane-based resin, and a silicon-based resin, and adding and mixing a plasticizer based on cyclohexane and a plasticizer based on benzoate (step 2).

[0068] Hereinafter, each step will be described, and first, Step 1 of preparing the water-based flame-retardant adhesive composition is a step of preparing a water-based polyvinyl chloride emulsion.

[0069] Specifically, the water-based polyvinyl chloride emulsion can be prepared by emulsion polymerization or seed emulsion polymerization of a vinyl chloride monomer alone or a mixture of a vinyl chloride monomer and a copolymerizable monomer copolymerizable therewith in a water-based medium while adding an emulsifier and a polymerization initiator.

[0070] Here, the types of the vinyl chloride monomer and the copolymerizable monomer copolymerizable therewith are as previously described.

[0071] Also, as the emulsifier, an anionic emulsifier or a nonionic emulsifier, etc. can be used alone or in combination of two or more. As the anionic emulsifier, a carboxylic acid, an alkyl sulfonic acid, an alkyl benzene sulfonic acid, an a-olefin sulfonic acid, or an alkyl phosphoric acid, etc. can be used. As the nonionic emulsifier, a polyoxyethylene ether, a polyoxyethylene alkyl phenyl ether, a polyoxyethylene alkenyl ether, a polyoxyethylene derivative, a glycerol fatty acid ester, a sorbitan fatty acid ester, a polyoxyethylene fatty acid ester, a silicon-based emulsifier, etc. can be used.

[0072] The emulsifier can be added to the water-based medium all at once before the polymerization reaction, or it can be continuously added to the water-based medium during the polymerization reaction. Alternatively, it can be added to the latex after the polymerization reaction is completed, and the above methods can be combined as necessary.

[0073] Also, in the emulsion polymerization or seed emulsion polymerization, a dispersing aid can be further used as necessary.

[0074] The dispersing aid is used together with the emulsifier, particularly a higher alcohol such as lauryl alcohol, myristyl alcohol, stearyl alcohol, or a higher fatty acid such as lauric acid, myristic acid, palmitic acid, stearic acid, etc., to maintain the stability of the polymerization and the latex.

[0075] Also, as the polymerization initiator used in the emulsion polymerization or seed emulsion polymerization, a water-soluble polymerization initiator such as ammonium persulfate, potassium persulfate, sodium persulfate, or hydrogen peroxide, etc. can be used, and a reducing agent such as sodium sulfite, sodium ascorbate, etc. can be used together as necessary.

[0076] Also, as the water-based medium, water such as distilled water, deionized water, etc. can be used.

[0077] By mixing the above components and performing polymerization, a water-based polyvinyl chloride emulsion (or a vinyl chloride resin latex) in which polyvinyl chloride microparticles are dispersed in a water-based medium (particularly water) can be prepared.

[0078] After the polymerization is completed, a process for removing unreacted monomers can be further optionally performed, and the polymerization conditions can be appropriately changed depending on the properties of the polyvinyl chloride to be achieved.

[0079] Also, in the aqueous polyvinyl chloride emulsion, the solid content including the polyvinyl chloride can be about 30 to about 60% by weight, but it can vary depending on the polymerization method.

[0080] Next, Step 2 is a step of mixing the aqueous polyvinyl chloride emulsion prepared in Step 1 with a base resin, and adding and mixing a cyclohexane-based plasticizer and a benzoate-based plasticizer.

[0081] Here, the types and mixing ratios of the base resin can be mixed in the same manner as described above.

[0082] Also, when the aqueous polyvinyl chloride emulsion is mixed with the base resin, a cyclohexane-based plasticizer and a benzoate-based plasticizer are further added, and the types and contents of the respective plasticizers are as described above.

[0083] The aqueous flame-retardant adhesive composition prepared according to the above preparation method can exhibit excellent flame retardancy even without using a general flame retardant. Specifically, when the flame retardancy is evaluated according to the UL94 V flame retardancy regulation, the adhesive composition exhibits V0 or VI flame retardancy. Thus, the cost can be reduced by replacing a conventional organic flame retardant, and the layer separation of the adhesive caused by the addition of an inorganic flame retardant is improved.

[0084] Thus, the aqueous flame-retardant adhesive composition is environmentally friendly, and can be used in various fields such as construction, industry, which require excellent flame retardancy and adhesion, and low-temperature stability.

[0085] Thus, according to another embodiment of the present application, there is provided an article including the aqueous flame-retardant adhesive composition. The article can be specifically a construction / industrial adhesive, an adhesive film, a decorative sheet, a flooring material, artificial leather, or a toy.

[0086] Hereinafter, the present application will be explained in more detail for better understanding of the present application. However, the following examples are only for illustrating the present application, and the scope of the present application is not limited thereto.

[0087] <Preparation of aqueous PVC emulsion>

[0088] Preparation Example

[0089] In a high-pressure reactor, 76 kg of deionized water, 39.55 kg of a vinyl chloride monomer, and 16.95 kg of a vinyl acetate monomer were added, and then an aqueous polyvinyl chloride emulsion in which a vinyl chloride / vinyl acetate copolymer was dispersed in water was prepared by emulsion polymerization at a high-pressure reactor temperature of 65°C.

[0090] The polyvinyl chloride in the prepared aqueous polyvinyl chloride emulsion has a Tg of 60°C, an average particle diameter of 180 nm, a weight average molecular weight of 75,000 g / mol, and a solid content in the emulsion of 43 wt%.

[0091] <Preparation of the aqueous flame-retardant adhesive composition>

[0092] Example 1

[0093] As the base resin, an aqueous VAE emulsion (VINNAPAS TM EP 706, Wacker Chemie AG, average particle diameter 1 pm, Tg 5°C) and the solid content of the aqueous PVC emulsion prepared in the preparation example were mixed in a weight ratio of 70:30, and based on 100 parts by weight of the solid content of the base resin, 20 parts by weight of a cyclohexane-based plasticizer (cyclohexane-1,4-dicarboxylic acid di(2-ethylhexyl) ester, Eco-DEHCH, HANWHA) was additionally added, and based on 100 parts by weight of the solid content of the base resin, 10 parts by weight of a benzoate-based plasticizer (dipropylene glycol dibenzoate, BF 9-88, Eastman) was additionally added, thereby preparing the aqueous flame-retardant adhesive composition.

[0094] Example 2

[0095] The aqueous flame-retardant adhesive composition was prepared by the same method as in Example 1, except that 30 parts by weight, not 10 parts by weight, of the benzoate-based plasticizer (dipropylene glycol dibenzoate, BF 9-88, Eastman) was used based on 100 parts by weight of the solid content of the base resin.

[0096] Example 3

[0097] The aqueous flame-retardant adhesive composition was prepared by the same method as in Example 1, except that diethylene glycol dibenzoate (BF 50, Eastman) was used as the benzoate-based plasticizer.

[0098] Example 4

[0099] The aqueous flame-retardant adhesive composition was prepared by the same method as in Example 1, except that diethylene glycol dibenzoate (BF 50, Eastman) was used as the benzoate-based plasticizer in an amount of 30 parts by weight based on 100 parts by weight of the solid content of the base resin.

[0100] Comparative Example 1

[0101] An aqueous flame-retardant adhesive composition was prepared by the same method as in Example 1 except that a benzoate-based plasticizer was not used.

[0102] Comparative Example 2

[0103] An aqueous flame-retardant adhesive composition was prepared by the same method as in Example 1 except that a cyclohexane-based plasticizer was not used.

[0104] Experimental Example

[0105] The flame retardancy, adhesive strength, low temperature stability, extraction resistance and processability of the adhesive compositions prepared in the examples and comparative examples were evaluated. The results are shown in Table 2 below.

[0106] (1) Flame Retardancy: The flame retardancy was determined according to the UL94 V (Vertical Burning Test) flame retardancy test on a bar sample of 125 mm * 13 mm * 1 mm, and evaluated according to the standards described in Table 1 below.

[0107] <Flame Retardancy Evaluation Standards>

[0108] [Table 1]

[0109]

[0110] (2) Low Temperature Stability: Each of the adhesive compositions prepared in the examples and comparative examples was stored in an oven at -4°C and -15°C for 1 day, and then the state and viscosity of the composition were confirmed.

[0111] <Evaluation Standards>

[0112] Excellent: Both the state and viscosity of the composition were normal

[0113] Good: The viscosity of the composition changed (usable level)

[0114] Poor: Caking due to aggregation (unusable level)

[0115] (3) Storage Stability: The BF viscosity of each of the adhesive compositions prepared in the examples and comparative examples was measured after 1 hour in a 25°C oven, the measured value was taken as the initial viscosity, the composition was stored for 7 days, and then the viscosity was confirmed.

[0116] <Evaluation Standards>

[0117] Excellent: The viscosity change (initial viscosity / viscosity after 7 days) of the composition was 5% or less

[0118] Good: The viscosity change (initial viscosity / viscosity after 7 days) of the composition was 15% or less

[0119] Good: Viscosity change (initial viscosity / viscosity after 7 days) of the composition is 5% or less

[0120] (4) Adhesion strength (peeling strength): Measured by 180° peeling strength test (ISO 8510-2).

[0121] On both adhering sides of a test specimen of width 25 mm*length 150 mm, adhesive was coated in a thickness range of 0.5 mm, and the coating amount was controlled to be 400-500 g / m2. After the adhesive was coated to the adhering side, the open time was maintained for about 10 minutes. After curing for 7 days under pressing with a load of about 49 N (5 kgf), the test specimen was used for the test. One end of the adhered part of the test specimen was peeled off by about 50 mm, and both sides were fixed to the clamps of the testing machine. The tensile speed or moving speed of the clamps was set to 200 ± 20 mm per minute.

[0122] (5) Resistance to extraction: The coated / dried composition was then placed with / without oil paper on the coated surface, a load of 5 kg was applied in a constant temperature oven at 60°C, stored for 7 days, and the weight change of the sheet was measured, with reference to the test standard of ISO 177:1988.

[0123] <Evaluation Criteria>

[0124] Excellent: Sheet weight change 3% or less

[0125] Good: Sheet weight change 5% or less

[0126] Poor: Sheet weight change more than 5%

[0127] (6) Processability (gelation speed): The gelation speed was measured at a temperature of 120°C using an SVNC (scanning vibration needle type curing instrument). As the gelation proceeds in the SVNC device, the amplitude decreases, and using this decreased speed, the gelation speed was compared and measured, and the gelation speed was scored (very excellent 5 > 4 > 3 > 2 > 1 very poor)

[0128] [Table 2]

[0129]

[0130] As shown in Table 2, it can be confirmed that in the examples of the present application, the low-temperature stability and the adhesion strength are equivalent to or better than those of the comparative examples, but the resistance to extraction and the processability are greatly improved.

Claims

1. An aqueous flame-retardant adhesive composition comprising a base resin of vinyl acetate-ethylene copolymer; an aqueous polyvinyl chloride emulsion; a cyclohexane-based plasticizer; and a benzoate-based plasticizer, wherein the polyvinyl chloride in the aqueous polyvinyl chloride emulsion has an average particle diameter of 100 nm to 1 μm, and a weight average molecular weight of 45,000 to 300,000 g / mol, wherein, based on 100 parts by weight of the base resin solid content, the cyclohexane-based plasticizer is contained in an amount of 10 to 30 parts by weight, and the benzoate-based plasticizer is contained in an amount of 5 to 30 parts by weight.

2. The aqueous fire-retardant adhesive composition according to claim 1, wherein, the base resin is an aqueous emulsion.

3. The aqueous fire-retardant adhesive composition of claim 1, wherein, based on 100 parts by weight of the base resin solid content, the aqueous polyvinyl chloride emulsion solid content is contained in an amount of 10 to 90 parts by weight.

4. The aqueous fire-retardant adhesive composition of claim 1, wherein, the composition contains the base resin solid content and the aqueous polyvinyl chloride emulsion solid content in a weight ratio of 10:90 to 90:

10.

5. The aqueous fire-retardant adhesive composition according to claim 1, wherein, The cyclohexane-based plasticizer is a compound comprising 2 C 4-10 alkyl cyclohexane dicarboxylate.

6. The aqueous fire-retardant adhesive composition of claim 1, wherein, the cyclohexane-based plasticizer includes one or more selected from the group consisting of cyclohexane-1,2-dicarboxylic acid di(2-ethylhexyl) ester, cyclohexane-1,3-dicarboxylic acid di(2-ethylhexyl) ester, cyclohexane-1,4-dicarboxylic acid di(2-ethylhexyl) ester, cyclohexane-1,2-dicarboxylic acid diisononyl ester, di(2-ethylhexyl)cyclohexane-1,4-diester, and cyclohexane-1,4-dicarboxylic acid dibutyl ester.

7. The aqueous fireblocking adhesive composition of claim 1, wherein, the benzoate-based plasticizer is one or more selected from the group consisting of sodium benzoate, isononyl benzoate, isodecyl benzoate, 2-propylheptyl benzoate, diethylene glycol dibenzoate, dipropylene glycol dibenzoate, 1,2-dipropylene glycol dibenzoate, and dibutyrolactone dibenzoate.

8. The aqueous flame-retardant adhesive composition according to claim 1, further comprising one or more additives selected from the group consisting of an initiator, a low molecular weight body, an epoxy resin, an ultraviolet stabilizer, an antioxidant, a colorant, a reinforcing agent, an antifoaming agent, a plasticizer, a foaming agent, an organic salt, a thickening agent, and a flame retardant.

9. The aqueous fireblocking adhesive composition of claim 1, wherein, the aqueous flame-retardant adhesive composition shows a flame retardancy of V0 or VI when evaluated for flame retardancy according to the flame retardancy regulation UL94 V.

10. A method of producing the aqueous flame-retardant adhesive composition according to claim 1, comprising the steps of: emulsion polymerizing or seed emulsion polymerizing a vinyl chloride monomer alone or a mixture of a vinyl chloride monomer and a copolymerizable monomer copolymerizable therewith in an aqueous medium to produce an aqueous polyvinyl chloride emulsion in which polyvinyl chloride is dispersed in the aqueous medium; and mixing the aqueous polyvinyl chloride emulsion with a base resin of vinyl acetate-ethylene copolymer, and adding and mixing a cyclohexane-based plasticizer and a benzoate-based plasticizer, wherein the polyvinyl chloride in the aqueous polyvinyl chloride emulsion has an average particle diameter of 100 nm to 1 μm, and a weight average molecular weight of 45,000 to 300,000 g / mol.

11. The method of claim 10, wherein, The cyclohexane-based plasticizer is a cyclohexane di- carboxylate ester compound comprising 2 C 4-10 alkyl groups.

12. The method of claim 10, wherein, The benzoate-based plasticizer is one or more selected from the group consisting of sodium benzoate, isononyl benzoate, isodecyl benzoate, 2-propylheptyl benzoate, diethylene glycol dibenzoate, dipropylene glycol dibenzoate, 1,2-dipropylene glycol dibenzoate, and dibutylene glycol dibenzoate.

13. An article comprising the aqueous flame-retardant adhesive composition of any one of claims 1 to 9.

14. The article of claim 13, wherein, The article is an adhesive, an adhesive film, a decorative sheet, a flooring material, artificial leather, or a toy.

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