Polyvinyl acetate resin modified polyurethane dispersion and preparation method thereof

Abstract

The invention discloses a polyvinyl acetate resin modified polyurethane dispersoid and a preparation method thereof, and belongs to the technical field of organic synthesis.The polyvinyl acetate resin modified polyurethane dispersoid is prepared by modifying the surfaces of polyvinyl acetate resin particles subjected to surface hydroxylation treatment with furan and maleimide derivatives respectively; doping the surface furan modified polyvinyl acetate resin particles and the surface maleimide modified polyvinyl acetate resin particles into polyurethane, and heating to enable furyl groups and amide groups on the surfaces of the particles to be subjected to D-A reaction (Diels-Alder reaction); thus, the doped resin particles are linked in polyurethane to form a net structure, and the whole polymer dispersion system is hardened; under heating or strong shear stress, furyl and amide groups which have been subjected to D-A reaction among resin particles in polyurethane are subjected to inverse D-A reaction for ring opening, so that a resin particle network in a corresponding area is disintegrated, and the polyvinyl acetate resin modified polyurethane dispersion is softened.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis, and in particular relates to a polyvinyl acetate resin modified polyurethane dispersion and a preparation method thereof. Background Art

[0002] Polyurethane materials play a key role in many industrial fields with their excellent elasticity, wear resistance and environmental adaptability. The application of this polymer material in industries such as furniture, construction, footwear, transportation and home appliances not only improves the functionality and durability of products, but also promotes environmental protection and energy saving.

[0003] However, polyurethane materials still have some limitations in terms of mechanical properties. Currently, the mechanical properties of polyurethane can be improved through modification, but it will also bring some processing difficulties. Therefore, it is necessary to balance and optimize the mechanical properties and processing properties of polyurethane materials. How to modify polyurethane to reduce the processing difficulty of polyurethane materials, improve the processing and use efficiency of polyurethane materials, and further improve the environmental protection standards of polyurethane materials, so as to prepare a polyurethane material with excellent mechanical properties and easy processing, is of great significance to expanding the application range of polyurethane materials and meeting the specific application requirements of materials. Summary of the invention

[0004] To solve the above problems, the object of the present invention is to provide a polyvinyl acetate resin modified polyurethane dispersion and a preparation method thereof.

[0005] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0006] A polyvinyl acetate resin modified polyurethane dispersion is composed of the following raw materials in parts by weight: 1 part of polyvinyl acetate resin particles modified with furan on the surface, 1-1.2 parts of polyvinyl acetate resin particles modified with maleimide on the surface and 10-20 parts of polyurethane.

[0007] The surface furan-modified polyvinyl acetate resin particles are prepared according to the following method: by weight, 1 part of surface hydroxylated polyvinyl acetate resin particles and 0.1-1 part of terminal carboxyl furan derivatives are added to 10-15 parts of organic solvent 1, and then 0.1-1 part of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 0.02-0.2 part of 4-dimethylaminopyridine are added thereto, and the mixture is stirred and mixed evenly, and the mixture is heated to 25-80° C. to react for 12-24 hours. After the reaction is completed, the organic solvent is removed by reduced pressure distillation, and the residue is washed with organic solvent 1 and water for 3-5 times respectively, and dried to obtain surface furan-modified polyvinyl acetate resin particles.

[0008] The organic solvent 1 is dichloromethane, chloroform, acetonitrile or ethyl acetate.

[0009] The method for preparing the carboxyl-terminated furan derivative comprises the following steps:

[0010] 1) In parts by weight, 1 part of methyl 3-bromopropionate and 0.6-1 part of furan methanol are added to 5-10 parts of organic solvent 2, stirred to dissolve, and then 0.7-2 parts of base 1 are added thereto, and the mixture is reacted at 50-110° C. for 12-24 hours. After the reaction is completed, 8-10 parts of water are added under ice bath to quench the reaction, and the solvent is removed by distillation under reduced pressure. The residue is washed with water 3-5 times and dried to obtain compound 1;

[0011] 2) Add 1 part of the compound 1 obtained in step 1) to 5-10 parts of an alcohol solvent, and then add 0.3-1 part of a base 2, and react at 25-50° C. for 6-8 hours. After the reaction is completed, remove the solvent by distillation under reduced pressure, wash the residue with water 3-5 times, and dry it to obtain a terminal carboxyl furan derivative.

[0012] In step 1), the organic solvent 2 is dimethyl sulfoxide or dimethylformamide.

[0013] In step 1), the base 1 is sodium hydride, potassium hydride, sodium tert-butoxide or potassium tert-butoxide.

[0014] The alcohol solvent in step 2) is methanol or ethanol.

[0015] In step 2), the base 2 is sodium hydroxide or potassium hydroxide.

[0016] The preparation method of the surface hydroxylated polyvinyl acetate resin particles is as follows:

[0017] In parts by weight, 1 part of polyvinyl acetate resin is added to a mixed solvent of 5 to 10 parts of an organic solvent 3 and an alcohol solvent, and then 0.5 to 1.5 parts of a base 2 is added thereto, and the mixture is reacted at 25 to 50° C. for 12 to 24 hours. After the reaction is completed, the solvent is removed by reduced pressure distillation, and the obtained residue is washed with water for 3 to 5 times, and then added to a mixed solution of 5 to 10 parts of chloroform and water to obtain a reaction solution, and then an inert gas is introduced into the reaction solution at a rate of 1 to 5 L / min, and the reaction solution is stirred at 5 to 50 r / min. After the solvent is evaporated, polyvinyl acetate resin particles with surface hydroxylation treatment are obtained.

[0018] The organic solvent 3 is tetrahydrofuran, chloroform, dichloromethane or acetone.

[0019] The mass ratio of the organic solvent 3 to the alcohol solvent in the mixed solvent of the organic solvent 3 and the alcohol solvent is 1:1-2.

[0020] The mass ratio of chloroform to water in the mixed solution of chloroform and water is 1-5:0.1.

[0021] The inert gas is nitrogen or argon.

[0022] The surface maleimide-modified polyvinyl acetate resin particles are prepared according to the following method: by weight, 1 part of surface hydroxylated polyvinyl acetate resin particles and 0.1-1.2 parts of terminal carboxyl maleimide derivatives are added to 10-15 parts of organic solvent 1, and then 0.08-0.8 parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 0.015-0.16 parts of 4-dimethylaminopyridine are added thereto, and the mixture is stirred and mixed evenly, and the mixture is heated to 25-80° C. to react for 12-24 hours. After the reaction is completed, the organic solvent is removed by reduced pressure distillation, and the residue is washed with organic solvent 1 and water for 3-5 times respectively, and dried to obtain surface maleimide-modified polyvinyl acetate resin particles.

[0023] The preparation method of the carboxyl-terminated maleimide derivative comprises the following steps:

[0024] (1) In parts by weight, 1 part of N-hydroxyethylmaleimide and 1.2-1.5 parts of methyl 3-bromopropionate are added to 8-15 parts of organic solvent 2, stirred to dissolve, and then 0.8-1.5 parts of base 1 are added, and the mixture is reacted at 50-110° C. for 12-24 hours. After the reaction is completed, 5-8 parts of water are added under ice bath to quench the reaction, and the solvent is removed by distillation under reduced pressure. The residue is washed with water 3-5 times and dried to obtain compound 2;

[0025] (2) Add 1 part of the compound 2 prepared in step (1) to 5-10 parts of an alcohol solvent, then add 0.25-1 part of a base 2, and react at 25-50° C. for 6-8 hours. After the reaction is completed, remove the solvent by distillation under reduced pressure, wash the residue with water 3-5 times, and dry it to obtain a terminal carboxyl maleimide derivative.

[0026] The preparation method of the polyvinyl acetate resin modified polyurethane dispersion comprises the following steps:

[0027] In parts by weight, 1 part of polyvinyl acetate resin particles modified with furan on the surface, 1 to 1.2 parts of polyvinyl acetate resin particles modified with maleimide on the surface and 10 to 20 parts of polyurethane are added to 10 to 50 parts of organic solvent 3, heated to 50 to 70° C., mixed and reacted for 24 to 48 hours, and filtered to obtain a polyvinyl acetate resin modified polyurethane dispersion;

[0028] The organic solvent 3 is tetrahydrofuran, chloroform, dichloromethane or acetone.

[0029] The synthetic route of the present invention is:

[0030] Synthesis of carboxyl-terminated furan derivatives:

[0031]

[0032] Synthesis of Carboxyl-Terminated Maleimide Derivatives:

[0033]

[0034] Compared with the prior art, the present invention has the following advantages:

[0035] The polyvinyl acetate resin modified polyurethane dispersion of the present invention is modified with furan and maleimide derivatives on the surface of polyvinyl acetate resin particles subjected to surface hydroxylation treatment, and then the polyvinyl acetate resin particles with furan modified on the surface and the polyvinyl acetate resin particles with maleimide modified on the surface are doped into polyurethane. On the one hand, the introduction of polyvinyl acetate resin increases the flexibility, chemical stability and aging resistance of the material; on the other hand, the furan group and the amide group on the surface of the particle can undergo DA reaction (Diels-Alder reaction) by heating, so that the doped resin particles are linked into a network structure in the polyurethane, and the cross-linking modification can improve the mechanical properties, thermal stability and chemical stability of the material; under heating or strong shear stress, the furan group and the amide group that have undergone DA reaction between the resin particles in the polyurethane undergo reverse DA reaction and ring opening, so that the resin particle network in the corresponding area is disintegrated, the polyvinyl acetate resin modified polyurethane dispersion is softened, and the reprocessability of the material is improved. The schematic diagram of its action is shown in FIG. Figure 1 shown.

[0036] The polyvinyl acetate resin modified polyurethane dispersion of the invention has excellent mechanical properties and improves the processability of the material, thus having good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram of the reversible change of the polyvinyl acetate resin modified polyurethane dispersion of the present invention under heating or strong shear stress conditions. DETAILED DESCRIPTION

[0038] In order to better understand the technical solution of the present invention, the above content of the present invention is further described in detail below through specific implementation methods in the form of embodiments, but this should not be understood as the scope of the above subject matter of the present invention being limited to the following examples. All technologies realized based on the above content of the present invention belong to the scope of the present invention.

[0039] The polyurethane used in this embodiment is a polyurethane with a model number of WHT-1172IC purchased from Shenzhen Ruidasheng Plastic Co., Ltd.

[0040] Example 1

[0041] Preparation of polyvinyl acetate resin particles with surface hydroxylation treatment:

[0042] 0.1 kg of polyvinyl acetate resin was added to a mixed solvent of 0.5 kg of tetrahydrofuran and ethanol, and then 0.05 kg of sodium hydroxide was added thereto, and the mixture was reacted at 25°C for 12 hours. After the reaction was completed, the solvent was removed by distillation under reduced pressure, and the residue was washed with water three times, and then added to a mixed solution of 0.5 kg of chloroform and water to obtain a reaction solution. Nitrogen was then introduced into the reaction solution at a rate of 1 L / min, and the reaction solution was stirred at 5 r / min. After the solvent was evaporated, polyvinyl acetate resin particles with surface hydroxylation were obtained.

[0043] The mass ratio of tetrahydrofuran to ethanol in the mixed solvent of tetrahydrofuran and ethanol is 1:1.

[0044] The mass ratio of chloroform to water in the mixed solution of chloroform and water is 1:0.1.

[0045] Preparation of carboxyl-terminated furan derivatives:

[0046] 1) 0.1 kg of methyl 3-bromopropionate and 0.06 kg of furan methanol were added to 0.5 kg of dimethyl sulfoxide, stirred to dissolve, and then 0.07 kg of sodium hydride was added thereto, and the mixture was reacted at 50° C. for 24 h. After the reaction was completed, 0.8 kg of water was added under ice bath to quench the reaction, and the solvent was removed by distillation under reduced pressure. The residue was washed with water 3 times and dried to obtain compound 1; 1 H NMR (300MHz, DMSO-d6, 293K): δ7.59(d,1H),6.35-6.51(m,2H),4.44(s,2H),3.68(t,2H),3.56(s,3H),2.45(t,2H).

[0047] 2) 0.1 kg of compound 1 obtained in step 1) was added to 0.5 kg of methanol, and then 0.03 kg of sodium hydroxide was added, and the mixture was reacted at 25° C. for 8 h. After the reaction was completed, the solvent was removed by distillation under reduced pressure, and the residue was washed with water 3 times and dried to obtain a terminal carboxyl furan derivative. 1 H NMR (300MHz, DMSO-d6, 293K): δ12.05(s,1H),7.57(d,1H),6.32-6.52(m,2H),4.46(s,2H),3.65(t,2H),2.42(t,2H).

[0048] Preparation of surface furan-modified polyvinyl acetate resin particles:

[0049] 0.1 kg of surface hydroxylated polyvinyl acetate resin particles and 0.01 kg of terminal carboxyl furan derivatives were added to 1 kg of dichloromethane, and then 0.01 kg of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 0.002 kg of 4-dimethylaminopyridine were added thereto, stirred and mixed evenly, heated to 25°C and reacted for 24 hours. After the reaction was completed, the organic solvent was removed by reduced pressure distillation, and the residue was washed with dichloromethane and water for 3 times respectively, and dried to obtain surface furan-modified polyvinyl acetate resin particles.

[0050] Preparation of carboxyl-terminated maleimide derivatives:

[0051] (1) 0.1 kg of N-hydroxyethylmaleimide and 0.12 kg of methyl 3-bromopropionate were added to 0.8 kg of dimethyl sulfoxide, stirred and dissolved, and then 0.08 kg of sodium hydride was added. The mixture was reacted at 50° C. for 24 h. After the reaction was completed, 0.5 kg of water was added under ice bath to quench the reaction. The solvent was removed by distillation under reduced pressure, and the residue was washed with water three times and dried to obtain compound 2; 1 H NMR (300MHz, DMSO-d6, 293K): δ7.79 (s, 2H), 3.52-3.82 (m, 9H), 2.40 (t, 2H).

[0052] (2) 0.1 kg of the compound 2 prepared in step (1) was added to 0.5 kg of methanol, and then 0.025 kg of sodium hydroxide was added, and the mixture was reacted at 25° C. for 8 h. After the reaction was completed, the solvent was removed by distillation under reduced pressure, and the residue was washed three times with water and dried to obtain a terminal carboxyl maleimide derivative. 1 H NMR (300MHz, DMSO-d6, 293K): δ12.02(s,1H),7.82(s,2H),3.61-3.77(m,6H),2.41(t,2H).

[0053] Preparation of polyvinyl acetate resin particles modified with maleimide on the surface:

[0054] 0.1 kg of surface hydroxylated polyvinyl acetate resin particles and 0.01 kg of terminal carboxyl maleimide derivatives were added to 1 kg of dichloromethane, and then 0.008 kg of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 0.0015 kg of 4-dimethylaminopyridine were added thereto, stirred and mixed evenly, heated to 25°C for reaction for 24 hours, and after the reaction was completed, the organic solvent was removed by reduced pressure distillation, and the residue was washed with dichloromethane and water for 3 times respectively, and dried to obtain surface maleimide-modified polyvinyl acetate resin particles.

[0055] Preparation of polyvinyl acetate resin modified polyurethane dispersion:

[0056] 0.1 kg of polyvinyl acetate resin particles modified with furan on the surface, 0.1 kg of polyvinyl acetate resin particles modified with maleimide on the surface and 1 kg of polyurethane were added into 1 kg of tetrahydrofuran, heated to 50° C., mixed and reacted for 48 hours, and filtered to obtain a polyvinyl acetate resin modified polyurethane dispersion.

[0057] Example 2

[0058] Preparation of polyvinyl acetate resin particles with surface hydroxylation treatment:

[0059] 0.1 kg of polyvinyl acetate resin was added to a mixed solvent of 0.7 kg of chloroform and methanol, and then 0.07 kg of potassium hydroxide was added thereto, and the mixture was reacted at 30°C for 15 hours. After the reaction was completed, the solvent was removed by distillation under reduced pressure. The residue was washed with water 5 times, and then added to a mixed solution of 0.8 kg of chloroform and water to obtain a reaction solution. Argon was then introduced into the reaction solution at a rate of 2 L / min, and the reaction solution was stirred at 20 r / min. After the solvent was evaporated, polyvinyl acetate resin particles with surface hydroxylation were obtained.

[0060] The mass ratio of chloroform to methanol in the mixed solvent of chloroform and methanol is 1:1.5.

[0061] The mass ratio of chloroform to water in the mixed solution of chloroform and water is 2:0.1.

[0062] Preparation of carboxyl-terminated furan derivatives:

[0063] 1) 0.1 kg of methyl 3-bromopropionate and 0.07 kg of furan methanol were added to 0.6 kg of dimethyl sulfoxide, stirred to dissolve, and then 0.1 kg of potassium hydride was added thereto, and the mixture was reacted at 60° C. for 22 h. After the reaction was completed, 0.85 kg of water was added under ice bath to quench the reaction, and the solvent was removed by distillation under reduced pressure. The residue was washed with water 4 times and dried to obtain compound 1;

[0064] 2) 0.1 kg of compound 1 obtained in step 1) was added to 0.6 kg of ethanol, and then 0.04 kg of potassium hydroxide was added, and the mixture was reacted at 30° C. for 7.5 h. After the reaction was completed, the solvent was removed by distillation under reduced pressure, and the residue was washed with water 4 times and dried to obtain a terminal carboxyl furan derivative.

[0065] Preparation of surface furan-modified polyvinyl acetate resin particles:

[0066] 0.1 kg of surface hydroxylated polyvinyl acetate resin particles and 0.03 kg of terminal carboxyl furan derivatives were added to 1.1 kg of chloroform, and then 0.03 kg of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 0.008 kg of 4-dimethylaminopyridine were added thereto, stirred and mixed evenly, heated to 35°C for reaction for 22 hours, and after the reaction was completed, the organic solvent was removed by reduced pressure distillation, and the residue was washed with chloroform and water for 4 times respectively, and dried to obtain surface furan-modified polyvinyl acetate resin particles.

[0067] Preparation of carboxyl-terminated maleimide derivatives:

[0068] (1) 0.1 kg of N-hydroxyethylmaleimide and 0.13 kg of methyl 3-bromopropionate were added to 1 kg of dimethylformamide, stirred to dissolve, and then 0.1 kg of potassium hydride was added. The mixture was reacted at 70° C. for 20 h. After the reaction was completed, 0.65 kg of water was added under ice bath to quench the reaction. The solvent was removed by distillation under reduced pressure, and the residue was washed with water 4 times and dried to obtain compound 2;

[0069] (2) 0.1 kg of the compound 2 prepared in step (1) was added to 0.6 kg of ethanol, and then 0.05 kg of potassium hydroxide was added, and the reaction was carried out at 30° C. for 7.5 hours. After the reaction was completed, the solvent was removed by distillation under reduced pressure, and the residue was washed with water 4 times and dried to obtain a terminal carboxyl maleimide derivative.

[0070] Preparation of polyvinyl acetate resin particles modified with maleimide on the surface:

[0071] 0.1 kg of surface hydroxylated polyvinyl acetate resin particles and 0.04 kg of terminal carboxyl maleimide derivatives were added to 1.1 kg of chloroform, and then 0.01 kg of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 0.008 kg of 4-dimethylaminopyridine were added thereto, stirred and mixed evenly, heated to 40°C for reaction for 20 hours, and after the reaction was completed, the organic solvent was removed by reduced pressure distillation, and the residue was washed with chloroform and water for 3 times respectively, and dried to obtain surface maleimide-modified polyvinyl acetate resin particles.

[0072] Preparation of polyvinyl acetate resin modified polyurethane dispersion:

[0073] 0.1 kg of polyvinyl acetate resin particles modified with furan on the surface, 0.11 kg of polyvinyl acetate resin particles modified with maleimide on the surface and 1.2 kg of polyurethane were added into 2 kg of dichloromethane, heated to 55° C., mixed and reacted for 40 hours, and filtered to obtain a polyvinyl acetate resin modified polyurethane dispersion.

[0074] Example 3

[0075] Preparation of polyvinyl acetate resin particles with surface hydroxylation treatment:

[0076] 0.1 kg of polyvinyl acetate resin was added to a mixed solvent of 0.9 kg of acetone and ethanol, and then 0.1 kg of potassium hydroxide was added thereto, and the mixture was reacted at 40°C for 18 hours. After the reaction was completed, the solvent was removed by distillation under reduced pressure. The residue was washed with water four times, and then added to a mixed solution of 0.9 kg of chloroform and water to obtain a reaction solution. Argon was then introduced into the reaction solution at a rate of 3 L / min, and the reaction solution was stirred at 30 r / min. After the solvent was evaporated, surface hydroxylated polyvinyl acetate resin particles were obtained.

[0077] The mass ratio of acetone to ethanol in the mixed solvent of acetone and ethanol is 1:1.8.

[0078] The mass ratio of chloroform to water in the mixed solution of chloroform and water is 3:0.1.

[0079] Preparation of carboxyl-terminated furan derivatives:

[0080] 1) 0.1 kg of methyl 3-bromopropionate and 0.08 kg of furan methanol were added to 0.7 kg of dimethylformamide, stirred and dissolved, and then 0.14 kg of sodium tert-butoxide was added thereto, and the reaction was carried out at 80° C. for 18 hours. After the reaction was completed, 0.9 kg of water was added under ice bath to quench the reaction, and the solvent was removed by distillation under reduced pressure. The residue was washed with water 5 times and dried to obtain compound 1;

[0081] 2) 0.1 kg of compound 1 obtained in step 1) was added to 0.8 kg of ethanol, and then 0.06 kg of potassium hydroxide was added, and the mixture was reacted at 40° C. for 7 h. After the reaction was completed, the solvent was removed by distillation under reduced pressure, and the residue was washed with water 5 times and dried to obtain a terminal carboxyl furan derivative.

[0082] Preparation of surface furan-modified polyvinyl acetate resin particles:

[0083] 0.1 kg of surface hydroxylated polyvinyl acetate resin particles and 0.06 kg of terminal carboxyl furan derivatives were added to 1.3 kg of ethyl acetate, and then 0.06 kg of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 0.014 kg of 4-dimethylaminopyridine were added thereto, stirred and mixed evenly, heated to 50° C. and reacted for 18 hours. After the reaction was completed, the organic solvent was removed by reduced pressure distillation, and the residue was washed with ethyl acetate and water for 5 times respectively, and dried to obtain surface furan-modified polyvinyl acetate resin particles.

[0084] Preparation of carboxyl-terminated maleimide derivatives:

[0085] (1) 0.1 kg of N-hydroxyethylmaleimide and 0.14 kg of methyl 3-bromopropionate were added to 1.2 kg of dimethylformamide, stirred and dissolved, and then 0.12 kg of sodium tert-butoxide was added. The mixture was reacted at 90° C. for 16 h. After the reaction was completed, 0.7 kg of water was added under ice bath to quench the reaction. The solvent was removed by distillation under reduced pressure, and the residue was washed with water 5 times and dried to obtain compound 2;

[0086] (2) 0.1 kg of the compound 2 prepared in step (1) was added to 0.7 kg of ethanol, and then 0.07 kg of potassium hydroxide was added, and the mixture was reacted at 40° C. for 7 h. After the reaction was completed, the solvent was removed by distillation under reduced pressure, and the residue was washed with water 5 times and dried to obtain a terminal carboxyl maleimide derivative.

[0087] Preparation of polyvinyl acetate resin particles modified with maleimide on the surface:

[0088] 0.1 kg of surface hydroxylated polyvinyl acetate resin particles and 0.06 kg of terminal carboxyl maleimide derivatives were added to 1.3 kg of acetonitrile, and then 0.05 kg of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 0.01 kg of 4-dimethylaminopyridine were added thereto, stirred and mixed evenly, heated to 55°C for reaction for 18 hours, and after the reaction was completed, the organic solvent was removed by reduced pressure distillation, and the residue was washed with acetonitrile and water for 4 times respectively, and dried to obtain surface maleimide-modified polyvinyl acetate resin particles.

[0089] Preparation of polyvinyl acetate resin modified polyurethane dispersion:

[0090] 0.1 kg of polyvinyl acetate resin particles modified with furan on the surface, 0.11 kg of polyvinyl acetate resin particles modified with maleimide on the surface and 1.5 kg of polyurethane were added into 3 kg of dichloromethane, heated to 60° C., mixed and reacted for 36 hours, and filtered to obtain a polyvinyl acetate resin modified polyurethane dispersion.

[0091] Example 4

[0092] Preparation of polyvinyl acetate resin particles with surface hydroxylation treatment:

[0093] 0.1 kg of polyvinyl acetate resin was added to a mixed solvent of 1 kg of dichloromethane and ethanol, and then 0.12 kg of potassium hydroxide was added thereto, and the mixture was reacted at 45°C for 22 hours. After the reaction was completed, the solvent was removed by distillation under reduced pressure. The residue was washed with water 5 times, and then added to a mixed solution of 0.9 kg of chloroform and water to obtain a reaction solution. Nitrogen was then introduced into the reaction solution at a rate of 4 L / min, and the reaction solution was stirred at 40 r / min. After the solvent was evaporated, polyvinyl acetate resin particles with surface hydroxylation were obtained.

[0094] The mass ratio of dichloromethane to ethanol in the mixed solvent of dichloromethane and ethanol is 1:1.9.

[0095] The mass ratio of chloroform to water in the mixed solution of chloroform and water is 4:0.1.

[0096] Preparation of carboxyl-terminated furan derivatives:

[0097] 1) 0.1 kg of methyl 3-bromopropionate and 0.09 kg of furan methanol were added to 0.9 kg of dimethylformamide, stirred and dissolved, and then 0.17 kg of potassium tert-butoxide was added thereto, and the mixture was reacted at 100° C. for 15 h. After the reaction was completed, 1 kg of water was added under ice bath to quench the reaction, and the solvent was removed by distillation under reduced pressure. The residue was washed with water 5 times and dried to obtain compound 1;

[0098] 2) 0.1 kg of compound 1 obtained in step 1) was added to 0.9 kg of methanol, and then 0.08 kg of potassium hydroxide was added, and the mixture was reacted at 45° C. for 6.5 h. After the reaction was completed, the solvent was removed by distillation under reduced pressure, and the residue was washed with water 5 times and dried to obtain a terminal carboxyl furan derivative.

[0099] Preparation of surface furan-modified polyvinyl acetate resin particles:

[0100] 0.1 kg of surface hydroxylated polyvinyl acetate resin particles and 0.08 kg of terminal carboxyl furan derivatives were added to 1.4 kg of acetonitrile, and then 0.08 kg of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 0.017 kg of 4-dimethylaminopyridine were added thereto, stirred and mixed evenly, heated to 70°C for reaction for 15 hours, and after the reaction was completed, the organic solvent was removed by reduced pressure distillation, and the residue was washed with acetonitrile and water for 5 times respectively, and dried to obtain surface furan-modified polyvinyl acetate resin particles.

[0101] Preparation of carboxyl-terminated maleimide derivatives:

[0102] (1) 0.1 kg of N-hydroxyethylmaleimide and 0.14 kg of methyl 3-bromopropionate were added to 1.4 kg of dimethyl sulfoxide, stirred to dissolve, and then 0.14 kg of potassium tert-butoxide was added. The mixture was reacted at 100° C. for 14 h. After the reaction was completed, 0.75 kg of water was added under ice bath to quench the reaction. The solvent was removed by distillation under reduced pressure, and the residue was washed with water 5 times and dried to obtain compound 2;

[0103] (2) 0.1 kg of the compound 2 prepared in step (1) was added to 0.9 kg of methanol, and then 0.09 kg of sodium hydroxide was added, and the mixture was reacted at 45° C. for 6.5 h. After the reaction was completed, the solvent was removed by distillation under reduced pressure, and the residue was washed with water 5 times and dried to obtain a terminal carboxyl maleimide derivative.

[0104] Preparation of polyvinyl acetate resin particles modified with maleimide on the surface:

[0105] 0.1 kg of surface hydroxylated polyvinyl acetate resin particles and 0.09 kg of terminal carboxyl maleimide derivatives were added to 1.4 kg of ethyl acetate, and then 0.07 kg of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 0.014 kg of 4-dimethylaminopyridine were added thereto, stirred and mixed evenly, heated to 70°C for reaction for 15 hours, and after the reaction was completed, the organic solvent was removed by reduced pressure distillation, and the residue was washed with ethyl acetate and water for 5 times respectively, and dried to obtain surface maleimide-modified polyvinyl acetate resin particles.

[0106] Preparation of polyvinyl acetate resin modified polyurethane dispersion:

[0107] 0.1 kg of polyvinyl acetate resin particles modified with furan on the surface, 0.12 kg of polyvinyl acetate resin particles modified with maleimide on the surface and 1.8 kg of polyurethane were added into 4 kg of acetone, heated to 65° C., mixed and reacted for 30 hours, and filtered to obtain a polyvinyl acetate resin modified polyurethane dispersion.

[0108] Example 5

[0109] Preparation of polyvinyl acetate resin particles with surface hydroxylation treatment:

[0110] 0.1 kg of polyvinyl acetate resin was added to a mixed solvent of 1 kg of tetrahydrofuran and ethanol, and then 0.15 kg of sodium hydroxide was added thereto, and the mixture was reacted at 50°C for 24 hours. After the reaction was completed, the solvent was removed by distillation under reduced pressure. The residue was washed with water 5 times, and then added to a mixed solution of 1 kg of chloroform and water to obtain a reaction solution. Nitrogen was then introduced into the reaction solution at a rate of 5 L / min, and the reaction solution was stirred at 50 r / min. After the solvent was evaporated, polyvinyl acetate resin particles with surface hydroxylation were obtained.

[0111] The mass ratio of tetrahydrofuran to ethanol in the mixed solvent of tetrahydrofuran and ethanol is 1:2.

[0112] The mass ratio of chloroform to water in the mixed solution of chloroform and water is 5:0.1.

[0113] Preparation of carboxyl-terminated furan derivatives:

[0114] 1) 0.1 kg of methyl 3-bromopropionate and 0.1 kg of furan methanol were added to 1 kg of dimethyl sulfoxide, stirred to dissolve, and then 0.2 kg of potassium hydride was added thereto, and the mixture was reacted at 110° C. for 12 h. After the reaction was completed, 1 kg of water was added under ice bath to quench the reaction, and the solvent was removed by distillation under reduced pressure. The residue was washed with water 5 times and dried to obtain compound 1;

[0115] 2) 0.1 kg of compound 1 obtained in step 1) was added to 1 kg of ethanol, and then 0.1 kg of sodium hydroxide was added, and the mixture was reacted at 50° C. for 6 h. After the reaction was completed, the solvent was removed by distillation under reduced pressure, and the residue was washed with water 5 times and dried to obtain a terminal carboxyl furan derivative.

[0116] Preparation of surface furan-modified polyvinyl acetate resin particles:

[0117] 0.1 kg of surface hydroxylated polyvinyl acetate resin particles and 0.1 kg of terminal carboxyl furan derivatives were added to 1.5 kg of acetonitrile, and then 0.1 kg of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 0.02 kg of 4-dimethylaminopyridine were added thereto, stirred and mixed evenly, heated to 80°C for reaction for 12 hours, and after the reaction was completed, the organic solvent was removed by reduced pressure distillation, and the residue was washed with acetonitrile and water for 5 times respectively, and dried to obtain surface furan-modified polyvinyl acetate resin particles.

[0118] Preparation of carboxyl-terminated maleimide derivatives:

[0119] (1) 0.1 kg of N-hydroxyethylmaleimide and 0.15 kg of methyl 3-bromopropionate were added to 1.5 kg of dimethyl sulfoxide, stirred and dissolved, and then 0.15 kg of sodium tert-butoxide was added. The mixture was reacted at 110° C. for 12 h. After the reaction was completed, 0.8 kg of water was added under ice bath to quench the reaction. The solvent was removed by distillation under reduced pressure, and the residue was washed with water 5 times and dried to obtain compound 2;

[0120] (2) 0.1 kg of the compound 2 prepared in step (1) was added to 1 kg of methanol, and then 0.1 kg of sodium hydroxide was added, and the mixture was reacted at 50° C. for 6 h. After the reaction was completed, the solvent was removed by distillation under reduced pressure, and the residue was washed with water 5 times and dried to obtain a terminal carboxyl maleimide derivative.

[0121] Preparation of polyvinyl acetate resin particles modified with maleimide on the surface:

[0122] 0.1 kg of surface hydroxylated polyvinyl acetate resin particles and 0.12 kg of terminal carboxyl maleimide derivatives were added to 1.5 kg of ethyl acetate, and then 0.08 kg of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 0.016 kg of 4-dimethylaminopyridine were added thereto, and the mixture was stirred and mixed evenly, and heated to 80° C. for reaction for 12 hours. After the reaction was completed, the organic solvent was removed by reduced pressure distillation, and the residue was washed with ethyl acetate and water for 5 times respectively, and dried to obtain surface maleimide-modified polyvinyl acetate resin particles.

[0123] Preparation of polyvinyl acetate resin modified polyurethane dispersion:

[0124] 0.1 kg of polyvinyl acetate resin particles modified with furan on the surface, 0.12 kg of polyvinyl acetate resin particles modified with maleimide on the surface and 2 kg of polyurethane were added into 5 kg of tetrahydrofuran, heated to 70° C., mixed and reacted for 24 hours, and filtered to obtain a polyvinyl acetate resin modified polyurethane dispersion.

[0125] The polyvinyl acetate resin modified polyurethane dispersions prepared in Examples 1 to 5 were subjected to performance tests, wherein the tensile strength and elongation tests were conducted according to the method in ASTM D412, and the comparative example was unmodified polyurethane. It can be seen from the results in Table 1 that the polyvinyl acetate resin modified polyurethane dispersion prepared in the present invention has greater elongation and tensile strength than the comparative example, and has excellent mechanical properties.

[0126] Table 1 Mechanical properties of prepared materials

[0127] project Elongation(%) Tensile strength(MPa) Example 1 432 68.3 Example 2 449 71.2 Example 3 461 73.7 Example 4 454 72.4 Example 5 440 70.5 Comparative Example 255 44.9

[0128] The polyvinyl acetate resin modified polyurethane dispersion prepared in Example 3 was heated to 130°C to cause a decomposition and cross-linking reaction, and then the polyvinyl acetate resin modified polyurethane dispersion was quickly cooled to room temperature and then reacted at 60°C for 36 hours to obtain a reprocessed polyvinyl acetate resin modified polyurethane dispersion. This cycle was repeated three times, and the obtained reprocessed polyvinyl acetate resin modified polyurethane dispersions were tested for mechanical properties, and the test results are shown in Table 2. It can be seen from the results in Table 2 that the mechanical properties of the polyvinyl acetate resin modified polyurethane dispersion prepared by the present invention remain basically unchanged after multiple cycles of DA reaction, and the processability is good, which has broad application prospects.

[0129] Table 2 Reprocessing performance test results

[0130] frequency Elongation(%) Tensile strength(MPa) 0 461 73.7 1 457 72.5 2 453 72.1 3 451 72.0

[0131] Although the above describes the specific implementation methods of the present invention, it does not limit the scope of protection of the present invention. Based on the technical solution of the present invention, various modifications or variations that can be made by those skilled in the art without creative work are still within the scope of protection of the present invention.

Claims

1. A polyvinyl acetate resin modified polyurethane dispersion, characterized in that: The invention is composed of the following raw materials in parts by weight: 1 part of polyvinyl acetate resin particles with surface modified by furan, 1-1.2 parts of polyvinyl acetate resin particles with surface modified by maleimide and 10-20 parts of polyurethane.

2. The polyvinyl acetate resin modified polyurethane dispersion according to claim 1, characterized in that: The surface furan-modified polyvinyl acetate resin particles are prepared according to the following method: by weight, 1 part of surface hydroxylated polyvinyl acetate resin particles and 0.1-1 part of terminal carboxyl furan derivatives are added to 10-15 parts of organic solvent 1, and then 0.1-1 part of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 0.02-0.2 part of 4-dimethylaminopyridine are added thereto, and the mixture is stirred and mixed evenly, and the mixture is heated to 25-80° C. to react for 12-24 hours. After the reaction is completed, the organic solvent is removed by reduced pressure distillation, and the residue is washed with organic solvent 1 and water for 3-5 times, respectively, and dried to obtain surface furan-modified polyvinyl acetate resin particles; The organic solvent 1 is dichloromethane, chloroform, acetonitrile or ethyl acetate.

3. The polyvinyl acetate resin modified polyurethane dispersion according to claim 2, characterized in that: The method for preparing the carboxyl-terminated furan derivative comprises the following steps: 1) In parts by weight, 1 part of methyl 3-bromopropionate and 0.6-1 part of furan methanol are added to 5-10 parts of organic solvent 2, stirred to dissolve, and then 0.7-2 parts of base 1 are added thereto, and the mixture is reacted at 50-110° C. for 12-24 hours. After the reaction is completed, 8-10 parts of water are added under ice bath to quench the reaction, and the solvent is removed by distillation under reduced pressure. The residue is washed with water 3-5 times and dried to obtain compound 1; 2) Add 1 part of the compound 1 obtained in step 1) to 5-10 parts of an alcohol solvent, and then add 0.3-1 part of a base 2, and react at 25-50° C. for 6-8 hours. After the reaction is completed, remove the solvent by distillation under reduced pressure, wash the residue with water 3-5 times, and dry it to obtain a terminal carboxyl furan derivative.

4. The polyvinyl acetate resin modified polyurethane dispersion according to claim 3, characterized in that: The organic solvent 2 in step 1) is dimethyl sulfoxide or dimethylformamide; the base 1 in step 1) is sodium hydride, potassium hydride, sodium tert-butoxide or potassium tert-butoxide; the alcohol solvent in step 2) is methanol or ethanol; the base 2 in step 2) is sodium hydroxide or potassium hydroxide.

5. The polyvinyl acetate resin modified polyurethane dispersion according to claim 4, characterized in that: The preparation method of the surface hydroxylated polyvinyl acetate resin particles is as follows: In parts by weight, 1 part of polyvinyl acetate resin is added to a mixed solvent of 5 to 10 parts of an organic solvent 3 and an alcohol solvent, and then 0.5 to 1.5 parts of a base 2 is added thereto, and the mixture is reacted at 25 to 50° C. for 12 to 24 hours. After the reaction is completed, the solvent is removed by reduced pressure distillation, and the obtained residue is washed with water for 3 to 5 times, and then added to a mixed solution of 5 to 10 parts of chloroform and water to obtain a reaction solution, and then an inert gas is introduced into the reaction solution at a rate of 1 to 5 L / min, and the reaction solution is stirred at 5 to 50 r / min. After the solvent is evaporated, polyvinyl acetate resin particles with surface hydroxylation treatment are obtained.

6. The polyvinyl acetate resin modified polyurethane dispersion according to claim 5, characterized in that: The organic solvent 3 is tetrahydrofuran, chloroform, dichloromethane or acetone; the mass ratio of the organic solvent 3 to the alcohol solvent in the mixed solvent of the organic solvent 3 and the alcohol solvent is 1:1-2.

7. The polyvinyl acetate resin modified polyurethane dispersion according to claim 5, characterized in that: The mass ratio of chloroform to water in the mixed solution of chloroform and water is 1-5:0.1; and the inert gas is nitrogen or argon.

8. The polyvinyl acetate resin modified polyurethane dispersion according to claim 5, characterized in that: The surface maleimide-modified polyvinyl acetate resin particles are prepared according to the following method: by weight, 1 part of surface hydroxylated polyvinyl acetate resin particles and 0.1-1.2 parts of terminal carboxyl maleimide derivatives are added to 10-15 parts of organic solvent 1, and then 0.08-0.8 parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 0.015-0.16 parts of 4-dimethylaminopyridine are added thereto, and the mixture is stirred and mixed evenly, and the mixture is heated to 25-80° C. to react for 12-24 hours. After the reaction is completed, the organic solvent is removed by reduced pressure distillation, and the residue is washed with organic solvent 1 and water for 3-5 times respectively, and dried to obtain surface maleimide-modified polyvinyl acetate resin particles.

9. The polyvinyl acetate resin modified polyurethane dispersion according to claim 8, characterized in that: The preparation method of the carboxyl-terminated maleimide derivative comprises the following steps: (1) In parts by weight, 1 part of N-hydroxyethylmaleimide and 1.2-1.5 parts of methyl 3-bromopropionate are added to 8-15 parts of organic solvent 2, stirred to dissolve, and then 0.8-1.5 parts of base 1 are added, and the mixture is reacted at 50-110° C. for 12-24 hours. After the reaction is completed, 5-8 parts of water are added under ice bath to quench the reaction, and the solvent is removed by distillation under reduced pressure. The residue is washed with water 3-5 times and dried to obtain compound 2; (2) Add 1 part of the compound 2 prepared in step (1) to 5-10 parts of an alcohol solvent, then add 0.25-1 part of a base 2, and react at 25-50° C. for 6-8 hours. After the reaction is completed, remove the solvent by distillation under reduced pressure, wash the residue with water 3-5 times, and dry it to obtain a terminal carboxyl maleimide derivative.

10. The method for preparing the polyvinyl acetate resin modified polyurethane dispersion according to claim 1, characterized in that: The following steps are involved: In parts by weight, 1 part of polyvinyl acetate resin particles modified with furan on the surface, 1 to 1.2 parts of polyvinyl acetate resin particles modified with maleimide on the surface and 10 to 20 parts of polyurethane are added to 10 to 50 parts of organic solvent 3, heated to 50 to 70° C., mixed and reacted for 24 to 48 hours, and filtered to obtain a polyvinyl acetate resin modified polyurethane dispersion; The organic solvent 3 is tetrahydrofuran, chloroform, dichloromethane or acetone.

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