A polymer aqueous dispersion

Abstract

This invention provides a polymer aqueous dispersion with good adhesive properties, long-term storage at room temperature, and good viscosity stability. Furthermore, this polymer aqueous dispersion is particularly suitable for bonding between fiber textile materials and polymer foam materials, exhibiting high wet bond strength and excellent water resistance.

Description

Technical Field

[0001] This invention relates to a polymer aqueous dispersion and its use in the interfacial bonding of porous polymer materials. Background Technology

[0002] Commercially available products 192CGN is a self-crosslinking aqueous dispersion containing an ethylene-vinyl acetate polymer. This product can crosslink at 150°C and is used for bonding nonwoven fabrics. The recommended method of use is: before use, […]. In product 192CGN, the catalyst is added at a ratio of 1 wt% (based on the product's solids content) and stirred until homogeneous. The catalyst is typically prepared as a 10% aqueous solution. Commonly used catalysts include ammonium chloride, citric acid, and sodium bisulfate. At room temperature, if... If the mixing time of 192CGN with the catalyst is too long, exceeding thirty minutes, the mixture will gel, the viscosity will increase significantly, and it will become unusable.

[0003] CN102869828B discloses a VAE aqueous dispersion for carpet bonding. The amount of protective colloid is less than 1 pphm, and the sum of the amounts of nonionic and anionic surfactants is between 2-4 pphm. This product has poor water resistance.

[0004] CN102333799B discloses a VAE aqueous dispersion suitable for bonding applications in paper products, plastics, textiles and fiber materials; in Example 41, the amount of hydroxyethyl cellulose (HEC) is 1.1 pphm, and the amount of nonionic surfactant is 2.0 pphm.

[0005] CN104411488B discloses a VAE aqueous dispersion for paper bonding. In Example 6, the amount of polyvinyl alcohol used is 0.2 pphm, the amount of anionic surfactant is 0.5 pphm, and the amount of nonionic surfactant is 3 pphm. Summary of the Invention

[0006] Currently, there is no adhesive product containing VAE emulsion with excellent water resistance.

[0007] This invention provides a polymer aqueous dispersion with high wet bond strength and excellent water resistance. It also features long-term storage at room temperature and good viscosity stability. Furthermore, this polymer aqueous dispersion is particularly suitable for bonding between polymer interface materials, and even more so for bonding between fiber textile materials and polymer foam materials.

[0008] As used in this article, the term "pphm" refers to the number of parts per 100 parts of the main monomer, that is, the number of parts per 100 parts of vinyl acetate and ethylene.

[0009] A polymer aqueous dispersion containing

[0010] Component (a) is one or more ethylene-vinyl ester copolymers.

[0011] Component (b) one or more protective colloids,

[0012] Optional component (c1) one or more nonionic surfactants, and

[0013] Optional component (c2) is one or more ionic surfactants.

[0014] The protective colloid of component (b) is less than or equal to 3.4 pphm, for example 1.8 pphm, 2.2 pphm, 2.4 pphm, 2.6 pphm, 2.8 pphm, 3 pphm, 3.2 pphm, preferably between 1 and 3.4 pphm, more preferably between 2 and 3.1 pphm, and even more preferably between 2.3 and 2.9 pphm;

[0015] The sum of the amounts of component (c1) nonionic surfactant and component (c2) ionic surfactant is less than 0.1 pphm, preferably less than or equal to 0.01 pphm.

[0016] The aqueous dispersion described above, wherein component (b) the protective colloid comprises partially alcoholyzed polyvinyl alcohol of component (b1) and fully alcoholyzed polyvinyl alcohol of component (b2).

[0017] In the aqueous dispersion described above, the sum of the amounts of partially alcoholyzed polyvinyl alcohol (b1) and fully alcoholyzed polyvinyl alcohol (b2) is less than or equal to 3.4 pphm, for example 1.6 pphm, 1.8 pphm, 2.2 pphm, 2.4 pphm, 2.6 pphm, 2.8 pphm, 3 pphm, 3.2 pphm, preferably between 1 and 3.4 pphm, more preferably between 2 and 3.1 pphm, and even more preferably between 2.3 and 2.9 pphm.

[0018] In the aqueous dispersion described above, the weight ratio of partially alcoholyzed polyvinyl alcohol (b1) to fully alcoholyzed polyvinyl alcohol (b2) is between 0.8 and 4, preferably between 1.01 and 3, more preferably between 1.05 and 1.9, for example 1.1, 1.2, 1.3, 1.4, 1.8, 2.0, 2.2, 2.4.

[0019] The aqueous dispersion described above, wherein the amount of polyvinyl alcohol (PVOH) is greater than 50 wt%, preferably greater than or equal to 65 wt%, more preferably greater than or equal to 75 wt%, more preferably greater than or equal to 85 wt%, and more preferably greater than or equal to 95 wt%, is calculated based on a total amount of protective colloid in component (b) of 100 wt%.

[0020] In the aqueous dispersion described above, the amount of polyvinyl alcohol partially hydrolyzed in component (b1) is less than or equal to 2 pphm, preferably less than or equal to 1.6 pphm, more preferably between 1.1 and 1.7 pphm, for example 1.8, 1.4, 1.2, 1.0 pphm.

[0021] In the aqueous dispersion described above, the amount of polyvinyl alcohol from total alcoholysis of component (b2) is less than or equal to 1.5 pphm, preferably less than or equal to 1.3 pphm, more preferably between 0.3 and 1.1 pphm, for example 0.4, 0.6, 0.8, 0.9 pphm.

[0022] In this invention, partially hydrolyzed polyvinyl alcohol refers to a product with a degree of hydrolysis between 87% and 89%, and fully hydrolyzed polyvinyl alcohol refers to a product with a degree of hydrolysis between 98% and 100%.

[0023] The aqueous dispersion described above, wherein component (b1) is partially hydrolyzed polyvinyl alcohol, and its 4 wt% aqueous solution has a viscosity of 20-28 mPa·s, preferably 21-27 mPa·s, as measured according to DIN 53015 at 20°C.

[0024] The aqueous dispersion described above, wherein component (b2) is a fully alcoholyzed polyvinyl alcohol, has a viscosity of 15-18 mPa·s, preferably 16-17 mPa·s, as measured by DIN 53015 at 20°C in a 4 wt% aqueous solution.

[0025] The aqueous dispersion described above, where PVOH refers to polyvinyl alcohol, has a viscosity of 3-5 mPa·s, 15-18 mPa·s, or 20-28 mPa·s at 20°C, as measured by DIN53015. Commonly traded products are PVOH04 / 88, PVOH17 / 88, and PVOH25 / 88.

[0026] In the aqueous dispersion described above, the amount of sodium vinyl sulfonate is less than 0.5 pphm, preferably less than or equal to 0.1 pphm, and more preferably less than 0.01 pphm.

[0027] The aqueous dispersion described above further contains component (f) one or more thickeners, the amount of which is less than or equal to 1 pphm, preferably less than or equal to 0.2 pphm, more preferably less than or equal to 0.5 pphm, and even more preferably between 0.05 and 0.2 pphm, for example 0.08, 0.1, 0.12, 0.14, 0.16, 0.18 pphm.

[0028] In this invention, the thickener component (f) includes component (f1) which is composed of ASE (alkali-swellable emulsion) thickener and HASE (hydrophobic modified alkali-swellable emulsion) thickener, and component (f2) natural polymer and its derivatives.

[0029] In the aqueous dispersion described above, component (f) is preferably component (f1), which is composed of ASE (alkali-swellable emulsion) thickener and HASE (hydrophobically modified alkali-swellable emulsion) thickener; preferably, it contains ASE thickener containing acrylamide and / or acrylic monomer; or preferably, it contains HASE thickener containing acrylamide and / or acrylic monomer.

[0030] There are two main categories of alkali-swellable acrylic thickeners: ASE (alkali-swellable emulsion) thickeners and HASE (hydrophobically modified alkali-swellable emulsion) thickeners. The former refers to copolymers of methacrylic acid with a non-water-soluble ester of the acid, while the latter refers to copolymers of a non-water-soluble ester of (meth)acrylic acid with a monomer possessing a so-called "associative" hydrophobic group based on methacrylic acid. Furthermore, these copolymers can be cross-linked.

[0031] The aqueous dispersion described above is a product in single-package form.

[0032] In the aqueous dispersion described above, in component (a) the ethylene-vinyl ester copolymer, the amount of vinyl ester monomer is greater than or equal to 70 wt%, preferably greater than or equal to 80 wt%, more preferably between 80-90 wt%, and even more preferably between 82-88 wt%, calculated with the total amount of all monomers being 100 wt%.

[0033] In the dispersion described above, in component (a) the ethylene-vinyl ester copolymer, the amount of ethylene monomer is less than or equal to 30 wt%, preferably between 10-20 wt%, more preferably between 12-18 wt%, calculated with the total amount of all monomers being 100 wt%.

[0034] In the aqueous dispersion described above, the amount of vinyl acetate and ethylene in component (a) is greater than or equal to 95 wt%, preferably greater than or equal to 98 wt%, more preferably greater than or equal to 99 wt%, and even more preferably greater than or equal to 99.9 wt%, calculated with component (a) being 100 wt%.

[0035] The aqueous dispersion described above, wherein component (a) contains vinyl acetate and ethylene as monomers.

[0036] The aqueous dispersion as described above, wherein the ratio of component (a) ethylene-vinyl ester copolymer to the total amount of all polymers and copolymers in the composition is greater than or equal to 0.8, preferably greater than or equal to 0.9, and more preferably greater than or equal to 0.95.

[0037] The aqueous dispersion as described above, wherein component (a) ethylene-vinyl ester copolymer is ethylene-vinyl acetate copolymer.

[0038] The aqueous dispersion described above, wherein the polymer aqueous dispersion is an emulsion, has a Brookfield viscosity of 3000-12000 mPa·s according to the ST-2 Brookfield viscosity test method; preferably between 5000-8000 mPa·s; and a Brookfield viscosity change rate of less than 100 wt% under storage conditions of 23°C for 60 days, preferably less than 30 wt%; more preferably less than 10 wt%; and a Brookfield viscosity change rate of less than 30 wt% under storage conditions of 50°C for 14 days.

[0039] The aqueous dispersion described above has a solid content between 49-66 wt%, preferably between 53-63 wt%, and more preferably between 54-60 wt%. For example, 55 wt%, 56 wt%, 57 wt%, 58 wt%, and 59 wt%.

[0040] In the aqueous dispersion described above, the amount of optional component (a') other copolymers is less than or equal to 1 wt%, preferably less than or equal to 0.1 wt%. Calculated based on 100 wt% of the aqueous dispersion, component (a') other copolymers include vinyl acrylic copolymers, styrene acrylate copolymers, styrene butadiene copolymers, acrylic polymers, and vinyl acetate homopolymers.

[0041] The above-described aqueous dispersions are used in the interfacial bonding of porous polymer materials.

[0042] The aqueous dispersion described above is used to improve water resistance at the bonding interface of porous polymer materials.

[0043] The aqueous dispersion described above is used to improve wet bonding performance at the bonding interface of porous polymer materials.

[0044] The improved water resistance refers to the definition of wet bond strength in the wet bond test according to the present invention.

[0045] The polymer porous material interface bonding is the bonding between one or more of the interfaces of fiber textile materials and polymer foam materials; preferably, it is the bonding between one or more of the interfaces of man-made fiber textile materials, man-made fiber nonwoven materials, natural fiber textile materials, natural fiber nonwoven materials, regenerated cellulose materials, EVA ethylene-vinyl acetate copolymer foam, and PU polyurethane foam; more preferably, it is the bonding between PU polyurethane foam and man-made fiber textile materials, or the bonding between PU polyurethane foam and natural fiber textile materials, or the bonding between EVA ethylene-vinyl acetate copolymer foam and man-made fiber textile materials, or the bonding between EVA ethylene-vinyl acetate copolymer foam and natural fiber textile materials.

[0046] The aqueous dispersions described above are used in bonding textile and nonwoven materials.

[0047] As described above, the Tg of the aqueous dispersion is between 0-5°C, preferably between 0-4°C, and more preferably between 0-2°C.

[0048] A composite material structure for shoe insoles, the structure comprising synthetic fiber textile material and polymer foam material, which are bonded together by the aforementioned aqueous dispersion.

[0049] Composite materials are obtained by interfacial bonding of porous polymer materials. Some composite products require frequent contact with water or frequent cleaning in their operating environments. These composite materials are used in applications such as shoe linings, insoles, and sportswear. Composite products with poor water resistance are prone to debonding upon contact with water, i.e., separation of the material interfaces. This results in a short product lifespan.

[0050] As described above, the preferred method for interfacial bonding of porous polymer materials is a layered bonding and lamination of man-made fiber textile materials and polymer foam materials.

[0051] As described above, the preferred interfacial bonding of the polymer porous material is the bonding between the polyester, acrylic, or cotton textile material and the EVA ethylene-vinyl acetate copolymer foam interface.

[0052] As described above, the preferred application of polymer porous material interfacial bonding is bonding between cotton textile materials.

[0053] As described above, in this application, a polymer aqueous dispersion is applied between the interfaces of a polymer porous material, and the resulting product is heated in contact with a heat source for a period of time.

[0054] As described above, the field of interfacial bonding of porous polymer materials does not include the field of bulk bonding of porous polymer materials. Bulk bonding of porous polymer materials mainly refers to the bonding of fibrous polymer materials with a diameter of less than 5 mm. For example, in the manufacturing process of nonwoven fabrics, adhesives are used to bond wood pulp fibers, rayon, cotton, wool, acetate fibers, etc., to form nonwoven fabrics; or in the papermaking process, adhesives are used to bond pulp fibers to form paper webs, paper, or paperboard.

[0055] As described above, the polymer aqueous dispersion is applied between the interfaces of the polymer porous materials, and the resulting product is heated in contact with a heat source at 100-200°C for 25 to 120 seconds to complete the drying step.

[0056] As described above, a roller coater is used to apply a polymer aqueous dispersion to the interface of a porous polymer material under certain pressure, and then a drying step is completed.

[0057] For the purposes described above, after the drying step is completed using a roller coater, no further hot pressing is required.

[0058] As described above, the coating weight of the polymer aqueous dispersion is 120-210 g / m². 2 between.

[0059] When the viscosity of the polymer aqueous dispersion is too low, the amount of adhesive taken up by the coating roller during production is small, resulting in poor product adhesion. When the viscosity of the polymer aqueous dispersion is too high, the amount of adhesive taken up by the coating roller is large, leading to excessive product coating and high consumption costs of the polymer aqueous dispersion, which is uneconomical.

[0060] The vinyl esters typically include vinyl esters of straight-chain or branched alkyl carboxylic acids having 1 to 15 carbon atoms, such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl pentanoate, vinyl 2-ethylhexanoate, vinyl laurate, or any combination thereof.

[0061] To enhance the properties of component (a) the ethylene-vinyl ester copolymer, in addition to vinyl ester and ethylene monomers, other comonomers may be included, such as halogenated vinyl groups, like vinyl chloride; olefins, like propylene; olefinically unsaturated carboxylic acids and their derivatives, such as fumaric acid, maleic acid, maleic anhydride, acrylamide, and acrylonitrile; pre-crosslinked or post-crosslinked comonomers, such as divinyl adipate, diallyl maleate, allyl methacrylate, triallyl cyanurate, acrylamide glycolic acid, and so on. Methyl acrylamide glycolate, N-hydroxymethylacrylamide, N-hydroxymethylmethacrylamide, N-hydroxymethylallyl carbamate, isobutoxy ether or ester of N-hydroxymethylacrylamide, isobutoxy ether or ester of N-hydroxymethylmethacrylamide, isobutoxy ether or ester of N-hydroxymethylallyl carbamate; epoxy functional comonomers, such as glycidyl methacrylate and glycidyl acrylate; silicone functional comonomers, such as vinyltrialkoxysilane and vinylmethyldialkoxysilane.

[0062] The amount of these other comonomers is less than or equal to 2 wt%, preferably less than or equal to 1 wt%, more preferably less than or equal to 0.1 wt%, calculated based on a vinyl ester monomer amount of 100 wt%.

[0063] The polymer is prepared by solution, emulsion, or suspension polymerization, preferably by emulsion polymerization, at a polymerization temperature typically between 20°C and 100°C, more preferably between 45°C and 80°C. Polymerization of gas-phase monomers such as ethylene, 1,3-butadiene, or vinyl chloride can also be carried out at absolute pressures typically between 5 bar and 100 bar. The required pH for polymerization is generally between 2.5 and 10, preferably between 3 and 8, which can be determined by known methods using acids, bases, or conventional buffer salts such as alkali metal phosphates or alkali metal carbonates.

[0064] The polymerization reaction is initiated by a combination of water-soluble or monomer-soluble initiators or redox initiators, as is commonly used in emulsion polymerization or suspension polymerization. Examples of water-soluble initiators include sodium, potassium, and ammonium salts of persulfate, hydrogen peroxide, tert-butyl peroxide, tert-butyl hydroperoxide, potassium perbisphosphate, tert-butyl peroxypentanoate, and azobisisobutyronitrile. In each case, the amount of the initiator used is typically 0.01 to 3 wt% of the total dry weight of the monomer.

[0065] As a redox initiator, a combination of the aforementioned initiator and reducing agent is used. Suitable reducing agents are alkali metal or ammonium sulfites, alkali metal or ammonium bisulfites, derivatives of alkali metal or ammonium hyposulfites, or alkali metal or ammonium sulfites. In each case, the amount of the reducing agent used is typically 0.01 to 3 wt% of the total dry weight of component (a) monomer.

[0066] To control molecular weight, modifiers can be used during polymerization. If a modifier is used, its amount is typically 0.01 to 5.0 wt% of the total dry weight of component (a) monomers, and it is introduced alone or premixed with the reaction components. Examples of such substances are n-dodecyl mercaptan, tert-dodecyl mercaptan, mercaptopropionic acid, methyl mercaptopropionate, isopropanol, and acetaldehyde.

[0067] Suitable protective colloids for polymerization include polyvinyl alcohol, polyvinyl acetal, polyvinylpyrrolidone, water-soluble polysaccharides such as starch (amylose and amylopectin), cellulose and its carboxymethyl, methyl, hydroxyethyl, hydroxypropyl derivatives, dextrin and cyclodextrin.

[0068] Polymerization reactions can be carried out in batches or continuously.

[0069] After polymerization, post-polymerization can be carried out using known methods to remove residual monomers, typically by post-polymerization methods initiated by redox catalysts. Volatile residual monomers can also be removed by distillation, preferably under reduced pressure, and, if appropriate, using an inert entrainment gas such as air, nitrogen, or steam passing through the polymerization mixture. The polymer aqueous dispersion obtained in this way has a solids content of 40 to 70 wt%.

[0070] Defoamers and anti-caking agents can be added to the polymer aqueous dispersion of the present invention to prepare a redispersible polymer powder in water. This process is a conventional fluidized bed drying, freeze-drying, or spray-drying process.

[0071] Sample preparation and testing methods

[0072] Glass transition temperature sample preparation and testing method ST-1:

[0073] A certain amount of polymer aqueous dispersion sample was taken, dried at 25°C overnight, and then placed in a vacuum oven at 40°C for 24 hours to obtain the dried polymer aqueous dispersion.

[0074] Take 8-15 mg of the dried polymer aqueous dispersion and, according to ISO 11357-1 2014, under nitrogen protection, use a NETZSCH F203 closed sample cell to heat from -80℃ to 100℃ at a heating rate of 10 K / min to obtain the glass transition temperature Tg of the dried polymer aqueous dispersion.

[0075] Test method ST-2 cloth viscosity:

[0076] According to GB / T 11175-2002, the viscosity of the sample was tested using a Brookfield RV / DV rotational viscometer at 25°C and 20 rpm using rotor No. 4.

[0077] The room temperature conditions of this invention refer to: temperature 23±2℃, relative humidity 65±5%.

[0078] Laboratory bond strength sample preparation method:

[0079] Following the modified test method of ISO 11339-2010, polyurethane foam and polyester fabric were cut into 15cm*20cm sheets. First, the polyurethane foam was laid flat on a glass plate, and the top and bottom ends were secured with 1.8cm wide 3M electrical tape. A polymer aqueous dispersion was applied to the polyurethane foam using a doctor blade, and then smoothed using a 300µm wet film preparer. The sample was then placed in an oven and heat-treated at 130℃ for 1 minute before being removed.

[0080] Then, the polymer aqueous dispersion was coated onto a glass plate using a 300μm wet film preparation device. The polyester fabric was then laid flat on the glass plate, pressed twice with a glass rod, and the polyester fabric was removed.

[0081] Finally, the polyester fabric and polyurethane foam are bonded together, pressed horizontally twice with a 2kg roller, placed in an oven, and heat-treated at 130℃ for a period of time before being removed.

[0082] When it is necessary to test the bonding performance between cotton fabrics, replace the above-mentioned polyester fabric and polyurethane foam with cotton fabrics respectively.

[0083] Test method ST-3 dry bond strength:

[0084] Following the method shown in Figure 1 of ISO 11339-2010, the above-described dry fabric sample was tested for 180° peel strength using a Shandong Langguang XLW(G)-PC intelligent electronic tensile testing machine. The vertical stretch distance of the fabric sample was 40 mm, and the width was 25.4 mm (i.e., 1 inch). The 2 mm values ​​at the front and rear ends were not considered. The stretching speed was 100 mm / min.

[0085] Test method ST-4 wet bond strength:

[0086] Refer to test method ST-3, but soak the above dry cloth sample in water at 25°C for 1 hour to obtain a wet cloth sample, and immediately test its bonding strength. Example

[0087] Unless otherwise specified, all dosages described in this invention are calculated in parts by weight.

[0088] Unless otherwise specified, the weight parts of each raw material in Table 1 are calculated with the total weight of vinyl acetate and ethylene monomers being 100 parts as a reference.

[0089] In Table 1, the solution concentration is the weight percentage of the solute in the solution.

[0090] PVOH 04 / 88 is a 20wt% aqueous solution containing 88wt% hydrolyzed polyvinyl alcohol. Its 4wt% aqueous solution has a viscosity of 4-5 mPa·s at 20°C as measured by DIN 53015. It should be prepared as a 20wt% aqueous solution before use.

[0091] PVOH 25 / 88 is a 10.3wt% aqueous solution containing 88wt% hydrolyzed polyvinyl alcohol. Its 4wt% aqueous solution has a viscosity of 25 mPa·s at 20°C as measured according to DIN 53015. It should be prepared as a 10.3wt% aqueous solution before use.

[0092] PVOH 17 / 99 is a 10wt% aqueous solution of 99wt% hydrolyzed polyvinyl alcohol. Its 4wt% aqueous solution has a viscosity of 17 mPa·s at 20°C as measured according to DIN 53015. It should be prepared as a 10wt% aqueous solution before use.

[0093] The EDTA-2Na 8wt% aqueous solution is EDTA-2Na prepared as an 8wt% aqueous solution before use.

[0094] FeAS 10wt% aqueous solution is ferrous ammonium sulfate prepared as a 10wt% aqueous solution before use.

[0095] tBHP 10wt% aqueous solution is tert-butyl hydroperoxide prepared as a 10wt% aqueous solution before use.

[0096] FF6 5wt% aqueous solution is disodium hydroxyacetinate sulfinate (purchased from Brüggemann Chemical incorporates) prepared as a 5wt% aqueous solution before use.

[0097] Preparation method

[0098] Step 1: Add deionized water, PVOH 25 / 88 10.3wt% aqueous solution, PVOH 17 / 99 10wt% aqueous solution, and FAS to a 5-liter reactor.

[0099] Heat the reactor to 70°C, add the first portion of vinyl acetate and ethylene, and keep the reactor pressure below 45 bar.

[0100] The temperature was raised to 70°C, and simultaneously, 10 wt% tert-butyl hydrogen peroxide aqueous solution and 5 wt% FF6 aqueous solution were added dropwise using a pump to initiate the reaction. The addition was continued until the reaction was complete. To initiate the reaction, the temperature was raised to 85°C, and the second portion of vinyl acetate and ethylene were continuously added, while maintaining the pressure in the reactor at approximately 58 bar.

[0101] Step 2: After reacting for 4 hours, the mixture is transferred to a degassing tank. A 10wt% tert-butyl hydrogen peroxide aqueous solution and a 5wt% FF6 aqueous solution are continuously added dropwise. Then, an antifoaming agent and a pH adjuster are added. After degassing for 30 minutes, the polymer aqueous dispersion is discharged. The product has a Tg between 0-5℃ and a solid content between 54-60wt%.

[0102] Referring to the steps above and the material composition in Table 1, preparation examples and comparative examples are provided.

[0103] Table 1

[0104]

[0105] *The ethylene usage in Table 1 refers to the amount of ethylene gas fed in each example.

[0106] Comparative Example C.Ex.3 failed to form a uniform aqueous dispersion. Examples Ex.1-2 and Comparative Examples C.Ex.1-2 and 4 all yielded stable aqueous dispersions, with viscosity changes of less than 100% after storage at 23°C for 60 days.

[0107] Table 2.1 Bonding of cotton fabrics to cotton fabrics using a hot press at 160℃ / 1min

[0108] Ex1 Ex2 C.Ex.1 C.Ex.2 C.Ex.3 C.Ex4 Dry bond strength (N) 50 33.4 48.3 46.6 / 44.50 Wet bond strength (N) 30.8 30.1 10.5 9.8 / 9.20 Retention rate 61.60％ 90.12％ 21.74％ 21.03％ / 20.67％

[0109] In Table 2.1, a retention rate greater than 50% indicates excellent water resistance. Samples bonded using Ex.1 and Ex.2 exhibit high wet bond strengths, both exceeding 15 N. More preferably, the sample using Ex.1 also demonstrates a dry bond strength greater than 40 N, exhibiting excellent overall performance.

[0110] Table 2.2 Bonding of polyurethane foam to polyester fabric using a hot press at 130℃ / 1min

[0111] Ex1 Ex2 C.Ex.1 C.Ex.2 C.Ex.3 C.Ex4 Dry bond strength (N) Greater than 7 Greater than 7 Greater than 7 Greater than 7 / Greater than 7 Wet bond strength (N) Greater than 7 Greater than 7 1.5 1.2 / 0.90

[0112] In Table 2.2, a dry bond strength greater than 7 indicates that the polyurethane foam bulk has failed. At this point, the interfacial bond strength is greater than the bulk strength of the polyurethane foam. Samples obtained using Ex.1 and Ex.2 bonding exhibit high wet bond strength and excellent water resistance.

Claims

1. A polymer aqueous dispersion, comprising... Component (a) is one or more ethylene-vinyl ester copolymers. Component (b) one or more protective colloids, Optional component (c1) one or more nonionic surfactants, and Optional component (c2) is one or more ionic surfactants. Component (b) contains a protective colloid of less than or equal to 2.2 pphm. The sum of the amounts of component (c1) nonionic surfactant and component (c2) ionic surfactant is less than 0.1 pphm; In component (a) the ethylene-vinyl ester copolymer, the amount of other comonomers is less than or equal to 0.1 wt%, calculated based on the amount of vinyl ester monomer as 100 wt%.

2. The aqueous dispersion as described in claim 1, wherein component (b) protective colloid is between 1 and 2.2 pphm.

3. The aqueous dispersion as described in claim 1, wherein the sum of the amounts of the nonionic surfactant of component (c1) and the ionic surfactant of component (c2) is less than or equal to 0.01 pphm.

4. The aqueous dispersion according to any one of claims 1-3, wherein component (b) the protective colloid comprises partially alcoholyzed polyvinyl alcohol of component (b1) and fully alcoholyzed polyvinyl alcohol of component (b2).

5. The aqueous dispersion of claim 4, wherein the weight ratio of partially alcoholyzed polyvinyl alcohol (b1) to fully alcoholyzed polyvinyl alcohol (b2) is between 0.8 and 4.

6. The aqueous dispersion of claim 4, wherein the amount of partially alcoholyzed polyvinyl alcohol in component (b1) is between 1.1 and 1.7 pphm.

7. In the aqueous dispersion of claim 4, the amount of polyvinyl alcohol of component (b2) after complete alcoholysis is between 0.3 and 1.1 pphm.

8. The use of the aqueous dispersion as described in any one of claims 1-3 and 5-7 in the interfacial bonding of porous polymer materials.

9. The use of the aqueous dispersion as described in any one of claims 1-3 and 5-7 to improve water resistance at the bonding interface of porous polymer materials.

10. The use of the aqueous dispersion as described in any one of claims 1-3 and 5-7 to improve wet bonding performance at the bonding interface of porous polymer materials.

11. Use of the aqueous dispersion as described in any one of claims 1-3 and 5-7 in bonding textile and nonwoven materials.

Images