Aqueous dispersion composition comprising ethylene-based copolymer

Abstract

An aqueous dispersion composition according to an embodiment of the present disclosure includes: a first ethylene-based copolymer having a melting temperature of 84 DEG C or more; and a second ethylene-based copolymer having a melting temperature of less than 80 DEG C, the content of the second ethylene-based copolymer being 70 wt% to 90 wt% based on the total weight of the first ethylene-based copolymer and the second ethylene-based copolymer, the total content of the first ethylene-based copolymer and the second ethylene-based copolymer being 70 wt% to 90 wt% based on the total weight of the solids of the aqueous dispersion composition, and 50% by weight or more.

Description

Technical Field

[0001] The present disclosure relates to an aqueous dispersion composition including an ethylene-based copolymer. Background Art

[0002] Ethylene-based copolymers (e.g., ethylene-(meth)acrylic acid copolymers) are used for various applications such as sealing materials, adhesive materials, packaging materials, and optical films. For example, they can be made into an aqueous dispersion and used for forming a coating film or an adhesive layer. The aqueous dispersion can be coated on the surface of a polymer film, paper, metal foil, fabric, etc., and then heated to form an adhesive layer or a welded layer for use.

[0003] Since an ethylene-carboxylic acid copolymer includes an acid group in the copolymer structure, it has adhesive properties by itself. Therefore, during the storage of the dispersion, a blocking phenomenon may occur, such as sticking to other media like a container. To solve the blocking phenomenon, when the dispersion includes an additive such as an anti-blocking agent, the adhesive strength of the dispersion and the mechanical properties of the resulting adhesive layer can be reduced.

[0004] In view of the above aspects, there is a need to design an aqueous dispersion with improved adhesion reliability. Summary of the Invention

[0005] One problem of the present disclosure is to provide an aqueous dispersion composition including an ethylene-based copolymer with improved adhesion reliability.

[0006] According to an embodiment of the present disclosure, the aqueous dispersion composition includes: a first ethylene-based copolymer having a melting temperature of 84 °C or higher; and a second ethylene-based copolymer having a melting temperature of lower than 80 °C, wherein the content of the second ethylene-based copolymer is 70 wt% to 90 wt% in the total weight of the first ethylene-based copolymer and the second ethylene-based copolymer, and the total content of the first ethylene-based copolymer and the second ethylene-based copolymer is 50 wt% or more in the total weight of the solid content of the aqueous dispersion composition.

[0007] In some embodiments, the first ethylene-based copolymer may include an ethylene-(meth)acrylic acid copolymer or an ethylene-maleic anhydride-alkyl acrylate copolymer.

[0008] In some embodiments, the ratio of (meth)acrylic acid or maleic anhydride in the first ethylene-based copolymer may be 10 wt% or less in the total weight of the first ethylene-based copolymer.

[0009] In some embodiments, the second ethylene-based copolymer may include an ethylene-(meth)acrylic acid copolymer.

[0010] In some embodiments, it may be that the ratio of (meth)acrylic acid in the second vinyl copolymer is 19% by weight or more based on the total weight of the second vinyl copolymer.

[0011] In some embodiments, it may be that the melting temperature of the first vinyl copolymer measured by differential scanning calorimetry (DSC) is 90°C to 110°C.

[0012] In some embodiments, it may be that the melting temperature of the second vinyl copolymer measured by differential scanning calorimetry (DSC) is 65°C or higher and lower than 80°C.

[0013] In some embodiments, it may be that the melt flow index (MFI) of the first vinyl copolymer measured at 190°C and 2.16 kg is 5 g / 10 min to 250 g / 10 min.

[0014] In some embodiments, it may be that the melt flow index (MFI) of the second vinyl copolymer measured at 190°C and 2.16 kg is 250 g / 10 min to 1500 g / 10 min.

[0015] In some embodiments, it may be that the density of the second vinyl copolymer is greater than the density of the first vinyl copolymer.

[0016] In some embodiments, it may be that the weight average molecular weight of the first vinyl copolymer is greater than the weight average molecular weight of the second vinyl copolymer.

[0017] In some embodiments, it may be that the aqueous dispersion composition further includes a neutralizing agent and an aqueous dispersion medium.

[0018] In some embodiments, it may be that the neutralizing agent includes at least one of NH4OH, organic amine, KOH, NaOH, CsOH, and LiOH.

[0019] In some embodiments, it may be that the aqueous dispersion composition has a solids content of 10% by weight to 30% by weight.

[0020] In some embodiments, it may be that the viscosity of the aqueous dispersion composition at 25°C is 100 cP to 10000 cP.

[0021] According to an exemplary embodiment, the aqueous dispersion composition may include heterogeneous vinyl copolymers having different melting temperatures from each other. The ratio of the content of the vinyl copolymer may be adjusted within a predetermined range. Thereby, the adhesion phenomenon during storage can be reduced, and while improving the barrier properties and heat resistance, the adhesive strength can be improved together.

[0022] The vinyl copolymer can be contained in the solid content of the aqueous dispersion composition in an amount equal to or more than a predetermined content. Accordingly, while the adhesiveness and anti-blocking properties can be enhanced, the mechanical properties, water resistance, and heat resistance of the coating layer can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic cross-sectional view showing a coating film and a multilayer film according to an exemplary embodiment.

[0024] REFERENCE NUMERALS: 100: Multilayer film, 10: Coating film, 20: Upper layer, 30: Lower layer. DETAILED DESCRIPTION

[0025] The aqueous dispersion composition according to an embodiment of the present disclosure may include a vinyl copolymer and an aqueous dispersion medium (e.g., water). The aqueous dispersion composition may further include a neutralizing agent.

[0026] The term “(meth)acrylic acid” used in the present disclosure is used to mean including both acrylic acid and methacrylic acid. The term “(meth)acrylate” used in the present disclosure is used to mean including both acrylate and methacrylate.

[0027] Hereinafter, embodiments of the present disclosure will be specifically described. However, it should be understood that the present disclosure is not limited to the specific embodiments illustrated exemplarily, and includes all modifications, equivalents, and alternatives included in the concept and technical scope of the present disclosure.

[0028] The aqueous dispersion composition may include heterogeneous vinyl copolymers having different melting temperatures from each other.

[0029] According to an exemplary embodiment, the vinyl copolymer may include a first vinyl copolymer having a melting temperature of 84° C. or higher and a second vinyl copolymer having a melting temperature of lower than 80° C.

[0030] The melting temperature Tm can be measured using a differential scanning calorimeter (DSC). The melting temperature Tm of the vinyl copolymer measured using the differential scanning calorimeter (DSC) can represent the temperature at which the crystallinity disappears in a semi-crystalline polymer as the temperature at which the vinyl copolymer is transformed from a solid state into a fluid liquid state.

[0031] Through the second vinyl copolymer, the dispersibility of the vinyl copolymer in the aqueous dispersion composition can be increased, and the fluidity of the aqueous dispersion composition can be improved, thereby improving the coating characteristics and coating uniformity.

[0032] However, due to the low melting temperature of the second vinyl copolymer, the heat resistance and barrier properties of the coating layer formed from the second vinyl copolymer can be reduced.

[0033] The first vinyl copolymer can improve the barrier properties and heat resistance. Therefore, through the first vinyl copolymer, the thermal stability and chemical stability of the coating layer can be enhanced, and the mechanical properties and barrier properties can be further improved.

[0034] According to an exemplary embodiment, the first vinyl copolymer may include an ethylene-(meth)acrylic acid copolymer or an ethylene-maleic anhydride-alkyl (meth)acrylate copolymer.

[0035] In one embodiment, the alkyl (meth)acrylate may include an alkyl group having 1 to 8 carbon atoms. For example, the alkyl (meth)acrylate may include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc.

[0036] According to an exemplary embodiment, the ratio of the acidic monomer (e.g., (meth)acrylic acid and / or maleic anhydride) in the first vinyl copolymer may be 15% by weight or less based on the total weight of the first vinyl copolymer. For example, the content of the (meth)acrylic acid and / or maleic anhydride-derived monomer in the total weight of the first vinyl copolymer may be 15% by weight or less or 10% by weight or less.

[0037] According to an exemplary embodiment, the second vinyl copolymer may include an ethylene-(meth)acrylic acid copolymer.

[0038] According to an exemplary embodiment, the ratio of the acidic monomer (e.g., (meth)acrylic acid) in the second vinyl copolymer may be 19% by weight or more based on the total weight of the second vinyl copolymer. For example, the content of the (meth)acrylic acid-derived monomer in the total weight of the second vinyl copolymer may be 19% by weight or more.

[0039] Through the acid group in the acidic monomer included in the second vinyl copolymer, the dispersibility of the vinyl copolymer in the aqueous dispersion composition can be further improved. In addition, due to the interaction between the acid group and the external medium, the water resistance, adhesion, and adhesiveness of the coating layer can be improved.

[0040] However, through the acid group of the second vinyl copolymer, during the storage of the dispersion, a blocking phenomenon may occur, such as sticking to other media like containers. According to an exemplary embodiment, through the first vinyl copolymer, the blocking phenomenon can be suppressed, and the anti-blocking property of the aqueous dispersion composition can be improved.

[0041] According to an exemplary embodiment, the content of the second vinyl copolymer may be 70% by weight to 90% by weight in the total weight of the first vinyl copolymer and the second vinyl copolymer. For example, the ratio of the contents of the first vinyl copolymer and the second vinyl copolymer may be 1:9 to 3:7 by weight.

[0042] When the content of the second vinyl copolymer is less than 70% by weight, the adhesion phenomenon of the aqueous dispersion composition can be increased, and the storage stability of the aqueous dispersion composition and the heat resistance and high-temperature water resistance of the coating layer formed from the aqueous dispersion composition can be reduced.

[0043] When the content of the second vinyl copolymer is greater than 90% by weight, the dispersibility, fluidity and coating properties of the aqueous dispersion composition are reduced, and the coating uniformity and the water resistance, adhesion and adhesion of the coating layer can be reduced.

[0044] In some embodiments, the content of the second vinyl copolymer may be 72% by weight to 88% by weight, 73% by weight to 87% by weight, 75% by weight to 87% by weight or 75% by weight to 85% by weight. Within this range, the anti-adhesion properties of the aqueous dispersion composition are ensured without reducing the dispersibility and coating properties, and the barrier properties and heat resistance of the coating layer can be further improved.

[0045] According to an exemplary embodiment, the content of the vinyl copolymer may be 50% by weight or more in the total solid weight of the aqueous dispersion composition. For example, the total content of the first vinyl copolymer and the second vinyl copolymer may be 50% by weight to 99.9% by weight, 60% by weight to 99% by weight, 70% by weight to 95% by weight or 70% by weight to 90% by weight in the total solid weight of the aqueous dispersion composition.

[0046] The vinyl copolymer is contained at a high concentration, so that the vinyl copolymer can function as a base polymer or a base resin, and the coating properties of the aqueous dispersion composition and the thermal stability and chemical stability of the coating layer can be further improved.

[0047] In one embodiment, the content of the second vinyl copolymer may be 50% by weight or more in the total solid weight of the aqueous dispersion composition. Thereby, the heat resistance, barrier properties and mechanical properties of the coating layer formed from the aqueous dispersion composition can be further improved.

[0048] In some embodiments, the melting temperature of the first vinyl copolymer may be 84°C to 110°C, 90°C to 110°C, 95°C to 105°C or 95°C to 102°C. Within this range, the adhesion phenomenon can be further reduced in the aqueous dispersion composition, and the fluidity of the aqueous dispersion composition and the heat resistance of the coating layer can be further improved.

[0049] In some embodiments, the melting temperature of the second vinyl copolymer can be 65 °C or higher and lower than 80 °C, 70 °C or higher and lower than 80 °C, 73 °C to 79 °C, or 75 °C to 79 °C. Within this range, the heat resistance and mechanical properties of the coating layer do not decrease sharply, and the dispersibility of the vinyl copolymer and the coating characteristics of the aqueous dispersion composition can be further improved.

[0050] In some embodiments, the ratio of the acidic monomer (acrylic acid and / or maleic anhydride) in the first vinyl copolymer in the total weight of the first vinyl copolymer can be 2 wt% to 15 wt%, 2 wt% to 10 wt%, or 2.5 wt% to 5 wt%. Within this range, the dispersibility in the aqueous dispersion composition can be improved, and the anti-blocking property can be further enhanced.

[0051] In some embodiments, the ratio of the acidic monomer (acrylic acid) in the second vinyl copolymer in the total weight of the second vinyl copolymer can be 19 wt% to 30 wt%, 19 wt% to 25 wt%, or 20 wt% to 23 wt%. Within this range, the adhesion and bonding strength of the coating layer to the substrate can be further improved without reducing the storage stability of the aqueous dispersion composition.

[0052] In some embodiments, the solid content in the total weight of the aqueous dispersion composition can be 10 wt% to 30 wt%, 15 wt% to 30 wt%, or 20 wt% to 30 wt%. Within this range, the fluidity and coating uniformity of the aqueous dispersion composition can be improved, and the volatile components can be easily removed, thereby further improving the mechanical properties, thermal stability, and chemical stability of the coating layer. For example, as the solid content of the aqueous dispersion composition increases, the gelation of the vinyl copolymer can be promoted, and it may be substantially difficult to adjust the viscosity and coating characteristics of the aqueous dispersion composition to an appropriate range.

[0053] In some embodiments, it can be that the melt flow index (MFI) of the second vinyl copolymer is greater than the melt flow index of the first vinyl copolymer. The melt flow index (MFI) can be measured under the conditions of 190 °C and 2.16 kg. For example, the melt flow index can be measured according to the ASTM D1238 standard test method (e.g., ASTM D1238:2023).

[0054] In one embodiment, the melt flow index (MFI) of the first vinyl copolymer can be 5 g / 10 min to 250 g / 10 min, 50 g / 10 min to 230 g / 10 min, or 100 g / 10 min to 230 g / 10 min. Within this range, the heat resistance and mechanical strength of the coating layer formed from the aqueous dispersion composition can be further improved.

[0055] In one embodiment, the melt flow index (MFI) of the second vinyl copolymer can be 250 g / 10 min to 1500 g / 10 min, or 250 g / 10 min to 1400 g / 10 min, 270 g / 10 min to 1000 g / 10 min, or 280 g / 10 min to 500 g / 10 min. Within this range, the melt fluidity of the aqueous dispersion composition can be increased, thereby improving the coating properties.

[0056] In some embodiments, it can be that the Vicat softening temperature of the first vinyl copolymer is greater than that of the second vinyl copolymer. The Vicat softening temperature of the copolymer can be measured according to the ASTM D1525 standard test method.

[0057] For example, the Vicat softening temperature of the first vinyl copolymer can be 70 °C to 95 °C, 75 °C to 90 °C, or 80 °C to 90 °C. For example, the Vicat softening temperature of the second vinyl copolymer can be below 50 °C, 30 °C to 50 °C, or 35 °C to 45 °C.

[0058] Within this range, the heat resistance, high-temperature water resistance, and high-temperature barrier properties of the coating layer formed from the aqueous dispersion composition can be improved, and morphological deformation caused by shrinkage, stretching, etc. at high temperatures can be inhibited.

[0059] In some embodiments, it can be that the density of the second vinyl copolymer is greater than that of the first vinyl copolymer. The density of the copolymer can be measured according to the ASTM D792 standard test method.

[0060] The second vinyl copolymer having a low melting temperature and a high acid value has a relatively high density characteristic, so that while the adhesion phenomenon of the aqueous dispersion composition can be further inhibited, the mechanical properties and strength of the coating layer can be further improved.

[0061] In one embodiment, the density of the first vinyl copolymer can be 0.920 g / cm 3 to 0.940 g / cm 3 , 0.925 g / cm 3 to 0.939 g / cm 3 or 0.930 g / cm 3 to 0.938 g / cm 3 . Within this range, through the first vinyl copolymer, the heat resistance and barrier properties of the coating layer can be further improved.

[0062] In one embodiment, the density of the second vinyl copolymer can be 0.950 g / cm 3 to 0.960 g / cm 3, 0.952 g / cm 3 to 0.959 g / cm 3 or 0.955 g / cm 3 to 0.959 g / cm 3 . Within the said range, the water dispersibility of the ethylene-based copolymer can be further improved, and through the second ethylene-based copolymer, the coating uniformity and water resistance of the coating layer can be further improved.

[0063] In some embodiments, the weight average molecular weight (Mw) of the ethylene-based copolymer can be from 10,000 to 60,000. The weight average molecular weight of the copolymer can be measured by the light scattering method using gel permeation chromatography (GPC).

[0064] Within the said range, the increase in the viscosity of the water dispersion composition can be inhibited, and the mechanical properties and strength of the coating layer formed from the water dispersion composition can be improved.

[0065] In one embodiment, the weight average molecular weight of the ethylene-based copolymer can be from 10,000 to 50,000 or from 20,000 to 45,000. Within the said range, the coating properties of the water dispersion composition, the stability and barrier properties of the coating layer, etc. can be further improved.

[0066] In some embodiments, it can be that the weight average molecular weight of the second ethylene-based copolymer is less than that of the first ethylene-based copolymer. Thus, through the second ethylene-based copolymer, the water resistance of the coating layer can be further improved, and through the first ethylene-based copolymer, the barrier properties and mechanical properties can be further improved.

[0067] In one embodiment, the weight average molecular weight of the first ethylene-based copolymer can be from 25,000 to 55,000, from 30,000 to 50,000 or from 35,000 to 45,000. Within the said range, the mechanical properties, stability and barrier properties of the coating layer formed from the water dispersion composition can be further improved.

[0068] In one embodiment, the weight average molecular weight of the second ethylene-based copolymer can be from 15,000 to 45,000, from 20,000 to 40,000 or from 25,000 to 35,000. Within the said range, the coating properties of the water dispersion composition can be improved, and the chemical stability and water resistance of the coating layer can be further improved.

[0069] Water can be provided as a solvent and / or dispersion medium for the ethylene-based copolymer. In some embodiments, the water can include pure water or deionized water.

[0070] A neutralizing agent is mixed with the ethylene-based copolymer, and through the neutralizing agent, the water dispersion composition can be substantially provided as a stable viscous fluid.

[0071] As a neutralizing agent, an alkaline compound can be used without particular limitation. In one embodiment, the neutralizing agent may include an organic base such as an organic amine compound or an inorganic base such as ammonium hydroxide (NH4OH), lithium hydroxide (LiOH), sodium hydroxide (NaOH), potassium hydroxide (KOH), cesium hydroxide (CsOH), etc. They can be used alone or in combination of two or more.

[0072] The neutralizing agent can perform an acid-base neutralization reaction with the acid groups (e.g., carboxyl groups) included in the vinyl copolymer. Thereby, the dispersibility of the aqueous dispersion composition can be improved and the amount of insoluble components can be reduced.

[0073] In one embodiment, triethylamine (TEA) can be used as the neutralizing agent. Triethylamine has high compatibility with the vinyl copolymer, so it can further promote the neutralization reaction between the neutralizing agent and the vinyl copolymer. Thereby, the aqueous dispersibility of the vinyl copolymer can be further improved and the viscosity of the aqueous dispersion composition can be reduced.

[0074] In some embodiments, the content of the neutralizing agent in the total weight of the aqueous dispersion composition can be 1 wt% to 10 wt% or 2 wt% to 6 wt%. Within this range, while suppressing the increase in the viscosity of the aqueous dispersion composition, the water dispersibility of the vinyl copolymer can be further improved.

[0075] In some embodiments, the aqueous dispersion composition may further include an inorganic salt compound. The inorganic salt compound can increase the ion concentration in the mixed solution, thereby reducing the viscosity of the aqueous dispersion liquid composition.

[0076] In one embodiment, the inorganic salt compound may include sodium chloride (NaCl), calcium chloride (CaCl2), sodium sulfite (Na2SO3), sodium sulfate (Na2SO4), sodium carbonate (Na2CO3), potassium chloride (KCl), sodium phosphate (Na3PO4), ammonium chloride (NH4Cl), etc.

[0077] In one embodiment, the content of the inorganic salt compound in the total weight of the aqueous dispersion composition can be 0.01 wt% to 0.5 wt%. Within this range, while suppressing the formation of precipitates of the inorganic salt compound, the viscosity of the aqueous dispersion composition can be further reduced.

[0078] In some embodiments, the viscosity of the aqueous dispersion composition measured at 25 °C can be 100 cP to 10000 cP. Within this range, while suppressing the reduction of the adhesion property, the coating property and coating uniformity of the aqueous dispersion composition can be further improved.

[0079] For example, the viscosity of the aqueous dispersion composition can be measured using a Brookfield viscometer at 25°C. In one embodiment, a plate spindle can be used as the viscometer to measure the viscosity.

[0080] In one embodiment, the viscosity of the aqueous dispersion composition measured at 25°C can be from 100 cP to 5000 cP or from 100 cP to 2500 cP. Within this range, the aqueous dispersion composition can be further uniformly coated while further improving the mechanical properties and barrier properties of the coating layer.

[0081] The aqueous dispersion composition can also include other additives within a range that does not damage the physical properties of the vinyl copolymer such as dispersibility and thermal properties. For example, the additives can include antistatic agents, surfactants, inorganic particles, anti-blocking agents, and the like.

[0082] The aqueous dispersion composition can be coated on various objects such as paper, resin films, and metal foils, thereby being used to improve the water resistance, heat resistance, crack resistance, insulation, adhesiveness, etc. of the objects.

[0083] In addition, the aqueous dispersion composition can also be used as a sealing material for packaging films including polyethylene, polypropylene, polymethyl methacrylate, polyethylene terephthalate, etc.

[0084] Figure 1 It is a schematic cross-sectional view showing a coated film and a multilayer film according to an exemplary embodiment.

[0085] Reference Figure 1 , the aqueous dispersion can be coated on a substrate and then dried, thereby forming a coated film 10. The substrate can include paper, resin film, or metal foil, etc.

[0086] In some embodiments, other layers can also be laminated on at least one side of the coated film 10 to form a multilayer film 100. For example, an upper layer 20 can be laminated on the upper part of the coated film 10, and a lower layer 30 can be laminated on the lower part to form a multilayer film 100. The other layers can include a polymer film layer and a metal thin film layer.

[0087] For example, the upper layer 20 can be a polymer film layer and the lower layer 30 can be a metal thin film layer. For example, a polyolefin layer can be joined to one side of the coated film 10, and an aluminum layer can be joined to the other side of the coated film 10.

[0088] In one embodiment, the upper layer 20 and the lower layer 30 can both be metal thin film layers. In one embodiment, the upper layer 20 and the lower layer 30 can also both be polymer film layers.

[0089] The coated film 10 or the multilayer film 100 can be provided as, for example, a food packaging material or a food coating material.

[0090] Hereinafter, for the purpose of facilitating the understanding of the present disclosure, test examples including specific examples and comparative examples are presented. However, they are only for exemplifying the present disclosure and are not used to limit the scope of the appended patent claims. Those skilled in the art should clearly understand that various modifications and changes can be made to the examples within the scope and technical concept of the present disclosure, and such modifications and changes should also fall within the scope of the appended patent claims.

[0091] Examples and Comparative Examples (1) Preparation of aqueous dispersion composition 860.1 g of water was filled into a 3000 ml glass double jacket (Autoclave) container. As recorded in Table 1, the first vinyl copolymer and the second vinyl copolymer were dry-blended, and 250 g (25% solids) of the copolymer mixture was added to the container. The first vinyl copolymer and the second vinyl copolymer were formed by neutralizing the monomers in Table 2 below, respectively.

[0092] 33 g (based on a neutralization degree of 60%) of TEA (triethylamine) was added to the container as a neutralizing agent, and 250 g of ethanol was added to adjust the reaction rate and viscosity.

[0093] After closing the glass double jacket container, it was continuously stirred at a speed of 300 rpm and heated to 130°C. After reacting at 130°C for 2 hours, the container was heated and cooled to 60°C, and the undispersed components were removed by filtration.

[0094]

Table 1

[0095] (2) Measurement of physical properties of vinyl copolymer 1) Method for measuring acrylic acid content (AA%) / maleic anhydride content (MAH%) The content of acidic monomers (AA% or MAH%) in the vinyl copolymer was measured by Fourier Transform Infrared Spectroscopy. A Deuterated Triglycine Sulfate detector was used, and Resolution ProTM software (Agilent Corporation) was used to calculate the content value.

[0096] Specifically, a 120 mg particulate ethylene copolymer sample was pressed in a hydraulic hot press (Hot Press; 130 °C) to obtain a 50-μm sheet. After measuring the background spectrum, the sheet sample was fixed at the center of a film holder through which the IR beam passed. In transmission mode, measurements were carried out at a resolution of 4 cm -1 and a repeat measurement number of 32 scans.

[0097] Three standard samples with known acrylic acid contents were pretreated in the same manner as the measurement samples, and thus a first-order calibration equation for the integrated value of the C-O peak with respect to the acrylic acid content was calculated. Then, the integrated value of the C-O peak of the measurement sample was substituted into the calibration equation to calculate the acidic monomer content (%).

[0098] 2) Method for measuring the melting temperature (Tm) The melting temperature was measured using differential scanning calorimetry (Differential Scanning Calorimeter, equipment name: DSC822e, Mettler Toledo).

[0099] Specifically, a 6 mg particulate ethylene copolymer sample was taken out and placed in an aluminum crucible, and a lid including a pinhole was covered.

[0100] As a purge gas, while supplying nitrogen at a flow rate of 50 mL / min, after heating from -50 °C to 200 °C at a rate of 10 °C / min (the first heating range), it was held at 200 °C for 1 minute. Then, it was cooled from 200 °C to -50 °C at a rate of 5 °C / min to crystallize the sample. In the second heating range, the temperature was changed from -50 °C to 200 °C at a rate of 10 °C / min, and the highest point of the melting peak generated in the second heating range was measured as the melting temperature (Tm).

[0101] 3) Method for measuring the melt flow index (MFI) The melt flow index (MFI) was measured in accordance with ASTM D1238. The measurement temperature was 125 °C and the weight of the weight was 2.16 kg. Using a 20-fold correlation of the value measured in accordance with ASTM D1238 (125 °C / 2.16 kg), the melt flow index (MFI) under the conditions of a measurement temperature of 190 °C and a weight of 2.16 kg of the weight was calculated.

[0102] 4) Measurement of the weight-average molecular weight (Mw) The weight-average molecular weight was measured using gel permeation chromatography (gel permeation chromatography, PL GPC220, Agilent) and polystyrene standard substances.

[0103] Specifically, 200 μL of an ethylenic copolymer sample was injected into a GPC system set at a temperature of 160 °C and a GPC flow rate of 1 mL / min. Three chromatographic columns (Agilent, PLgel Olexis 7.5X300 mm, 13 μm) and one guard column (Agilent, PLgel Olexis 7.5×50 mm, 13 μm) were connected to the GPC system.

[0104] The measurement results are shown together in Table 2 below.

[0105]

Table 2

[0106] In Table 2, AA is acrylic acid, MAH is maleic anhydride, and EA is ethyl acrylate.

[0107] In Table 2, the acidic monomer content (MAH%) of L8200 is 2.8% by weight, and the EA content (EA%) is 6.5% by weight. The acidic monomer content (AA%) of 5980i is 20.5%.

[0108] The density of 5980i measured according to ASTM D792 is 0.958 g / cm 3 , and the Vicat softening temperature of 5980i measured according to ASTM D1525 is 42 °C.

[0109] Experimental Example 1) Evaluation of water resistance The aqueous dispersion composition was coated on a paper substrate and dried at 150 °C for 5 minutes to obtain a specimen sheet. According to ISO532, the specimen sheet was made into a circular sample with an area of 100 cm 2 . After fixing the sample in a circular mold, 100 ml of boiling water was poured onto the sample, and then it was left standing for 10 minutes. The difference (water absorption) between the weight of the sample before evaluation (dry mass) and the weight of the sample after evaluation (wet mass) was measured, and the water resistance A was evaluated by the following formula.

[0110] A = (m2 - m1) × F m1: Dry mass (g) m2: Wet mass (g) F: 10000 / test area (100 cm 2 ) The A value of each copolymer was measured repeatedly. When the measured A value was less than 5 g / m 2When it is, it is marked as "<5" in Table 3 below. When the measured value of A is distributed between 5 g / m 2 and 20 g / m 2 , it is marked as "5 - 20" in Table 3 below.

[0111] 2) Evaluation of static friction coefficient and dynamic friction coefficient The aqueous dispersion composition is coated on the paper substrate and dried at 150°C for 5 minutes to obtain a specimen sheet.

[0112] The friction coefficient of the specimen sheet is measured using a friction coefficient measuring instrument (Plane Surface Friction Tester, TOYOSEIKI). Specifically, the specimen sheet is closely attached and fixed to a 60 mm × 60 mm quadrilateral plate to prepare a moving friction surface. After fixing the opposite surface of the moving friction surface on the glass substrate, the two surfaces are rubbed at a gravity of 500 g and a speed of 150 mm / min to measure the static friction coefficient and dynamic friction coefficient.

[0113] The measurement results are recorded in Table 3 below.

[0114]

Table 3

[0115] Referring to Table 3, the aqueous dispersion composition of the example has improved DSC evaluation, water resistance, static friction coefficient, and dynamic friction coefficient compared to the aqueous dispersion composition of the comparative example.

[0116] In Comparative Example 1, the aqueous dispersion composition includes only the second vinyl copolymer as a vinyl copolymer. The static friction coefficient and dynamic friction coefficient of the specimen sheet obtained from this aqueous dispersion composition are increased compared to the example.

[0117] In Comparative Example 2, the aqueous dispersion composition includes only the first vinyl copolymer as a vinyl copolymer. The water resistance of the specimen sheet obtained from this aqueous dispersion composition is decreased compared to the example.

Claims

1. A water-dispersible composition comprising: a first vinyl copolymer having a melting temperature of above 84 °C; and a second vinyl copolymer having a melting temperature of below 80 °C, wherein the content of the second vinyl copolymer is 70% to 90% by weight based on the total weight of the first vinyl copolymer and the second vinyl copolymer, and the total content of the first vinyl copolymer and the second vinyl copolymer is 50% by weight or more based on the total weight of the solid content of the water-dispersible composition.

2. The water-dispersible composition according to claim 1, wherein the first vinyl copolymer comprises an ethylene-(meth)acrylic acid copolymer or an ethylene-maleic anhydride-alkyl acrylate copolymer.

3. The water-dispersible composition according to claim 2, wherein the ratio of (meth)acrylic acid or maleic anhydride in the first vinyl copolymer is 10% by weight or less based on the total weight of the first vinyl copolymer.

4. The water-dispersible composition according to claim 1, wherein the second vinyl copolymer comprises an ethylene-(meth)acrylic acid copolymer.

5. The water-dispersible composition according to claim 4, wherein the ratio of (meth)acrylic acid in the second vinyl copolymer is 19% by weight or more based on the total weight of the second vinyl copolymer.

6. The water-dispersible composition according to claim 1, wherein the melting temperature of the first vinyl copolymer measured by differential scanning calorimetry is 90 °C to 110 °C.

7. The water-dispersible composition according to claim 1, wherein the melting temperature of the second vinyl copolymer measured by differential scanning calorimetry is 65 °C or above and below 80 °C.

8. The water-dispersible composition according to claim 1, wherein the melt flow index of the first vinyl copolymer measured at 190 °C and 2.16 kg is 5 g / 10 min to 250 g / 10 min.

9. The water-dispersible composition according to claim 1, wherein the melt flow index of the second vinyl copolymer measured at 190 °C and 2.16 kg is 250 g / 10 min to 1500 g / 10 min.

10. The water-dispersible composition according to claim 1, wherein the density of the second vinyl copolymer is greater than the density of the first vinyl copolymer.

11. The water-dispersible composition according to claim 1, wherein the weight-average molecular weight of the first vinyl copolymer is greater than the weight-average molecular weight of the second vinyl copolymer.

12. The water-dispersible composition according to claim 1, wherein the water-dispersible composition further comprises a neutralizing agent and an aqueous dispersion medium.

13. The water-dispersible composition according to claim 12, wherein the neutralizing agent comprises at least one of organic amines, NH4OH, KOH, NaOH, CsOH, and LiOH.

14. The water-dispersible composition according to claim 12, wherein the water-dispersible composition has a solid content of 10% to 30% by weight.

15. The water-dispersible composition according to claim 1, wherein The viscosity of the aqueous dispersion composition at 25 °C is from 100 cP to 10,000 cP.

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