Hydrolysis-resistant acetoacetamido-modified polyvinyl alcohol and a method for preparing the same

Abstract

The application discloses a kind of hydrolysis-resistant acetylacetamide modified polyvinyl alcohol and preparation method thereof, and the preparation method comprises the following steps: double vinyl ketone and first and alcohol amine compound are reacted to generate N-(hydroxyalkyl) acetylacetamide intermediate;Then trichloro cyanogen and N-(hydroxyalkyl) acetylacetamide intermediate are reacted to generate 3,5-bis[acetylacetamide alkoxyl] monochloro s-triazine;Finally, 3,5-bis[acetylacetamide alkoxyl] monochloro s-triazine is reacted with PVA in polar solvent to generate AAM-PVA.The AAM-PVA prepared in the application can be used as a protective colloid for polyvinyl acetate emulsion polymerization, and the prepared emulsion adhesive has obvious improvement in water resistance, tensile strength and stability;The raw materials of the application are cheap and easy to obtain, the preparation process is simple, the reaction conditions are mild, and there is no waste water and waste gas emission.

Description

Technical Field

[0001] This invention belongs to the field of protective colloids in emulsion polymerization, specifically relating to a hydrolysis-resistant acetylacetamide-modified polyvinyl alcohol and its preparation method. Background Technology

[0002] With the continuous development of society and economy and the improvement of people's living standards, people's requirements for the quantity and quality of timber are also increasing year by year. As a result, engineered wood products, made from timber or other non-timber materials and bonded together with adhesives, are playing an increasingly important role. The production of plywood is inseparable from the use of adhesives; therefore, optimizing the performance of adhesives plays a vital role in the timber processing industry.

[0003] Commonly used wood adhesives in my country mainly include phenolic, urea-formaldehyde, melamine-formaldehyde, epoxy resin adhesives, and polyvinyl acetate emulsion adhesives. Among these, phenolic, urea-formaldehyde, and melamine-formaldehyde resin adhesives are collectively referred to as "three-aldehyde adhesives," and the adhesives used in my country's wood-based panel industry are dominated by "three-aldehyde adhesives" and their modified forms. "Three-aldehyde adhesives" possess excellent water and high-temperature resistance and chemical stability; boards bonded with them exhibit strong weather resistance and excellent processing and usage stability. Furthermore, the raw materials for "three-aldehyde adhesives" are widely available and inexpensive, thus they are extensively used in plywood production. However, during the production and use of "three-aldehyde adhesives," harmful gases such as formaldehyde are released, polluting the air in production workshops and homes, thereby harming human health. With the increasing awareness of environmental protection and health, the existing adhesive market dominated by "three-aldehyde adhesives" no longer meets the needs of social environmental protection and sustainable development. Therefore, finding a safe, effective wood adhesive that meets the needs of large-scale production has become an inevitable trend in the development of the wood industry.

[0004] Vinyl acetate is one of the world's largest-produced organic chemical raw materials, with a global production capacity exceeding 5.85 million tons since 2000. Vinyl acetate is primarily used to manufacture polyvinyl acetate (PVAc), a thermoplastic adhesive obtained through the polymerization of vinyl acetate monomers. A patent for vinyl acetate synthesis was first granted in Germany in 1912, using water as a dispersant and vinyl acetate ester as a monomer, employing an emulsion polymerization method. Due to the high molecular weight, high bonding strength, and broad compatibility of polyvinyl acetate and its copolymers, they are easily mixed with various additives, allowing for viscosity adjustment and the formulation of diverse products. Therefore, they have rapidly become a general-purpose adhesive that can replace aldehyde-based adhesives. However, they also have many drawbacks in use, such as poor water and moisture resistance, and especially poor acid and alkali resistance, hindering their complete replacement of aldehyde-based adhesives.

[0005] Protective colloids are water-soluble polymers that function similarly to emulsifiers during emulsion polymerization and are an important component of the process. Protective colloids form a protective layer on the surface of latex particles through steric hindrance, preventing particle aggregation and reducing surface tension, thus stabilizing the emulsion. Adding protective colloids during the production of polyvinyl acetate emulsions can effectively control the size distribution of latex particles and improve emulsion stability. Furthermore, compared to ordinary emulsifiers, protective colloids can also improve the strength of the emulsion film and enhance its crack resistance. Commonly used protective colloids include polyethylene alcohol (PVA), polyvinylpyrrolidone, and hydroxyl cellulose. Animal glue and gelatin can also be used as protective colloids, with PVA being the most widely used and applied.

[0006] PVA itself is a water-soluble polymer that is non-toxic, odorless, and harmless, with good environmental compatibility. It also has good density, high crystallinity, and strong adhesion. It can be used as an emulsifying stabilizer (protective colloid) in the polymerization of polyvinyl acetate emulsion (PVAc), in the manufacture of water-soluble adhesives, sealants resistant to benzene solvents, and thermal adhesives in thermal paper, among other applications.

[0007]

[0008] To improve the water resistance of PVA and broaden its application areas, people often modify PVA with acetyl groups to prepare acetyl-modified polyvinyl alcohol (AA-PVA), which is then used in emulsion protective colloids. Patents US20030186811A1, US20040209014A1, US4624985A, and US 20030083200A1 describe the formation of AA-PVA by introducing acetylacetyl groups into polyvinyl alcohol, which can improve the water resistance and other properties of PVA to a certain extent. Patents CN200780000122.9, CN201010117420.X, CN201580046964.2, CN202311454792.5, and CN202410260710.1 describe the application of AA-PVA in the adhesives of polarizers, which can improve the performance and lifespan of polarizers. However, the improved water resistance achieved by modifying the acetoacetyl group alone is still insufficient to fully support its application in adhesives and protective colloids. This is because the acetoacetyl group is easily hydrolyzed under acidic or alkaline conditions, which reduces the degree of acetylation in PVA. This directly affects the performance of AA-PVA, thereby reducing its ability to act as a protective colloid in emulsion polymerization. Ultimately, this results in insufficient film strength, water resistance, and crosslinking properties after the emulsion film is formed.

[0009]

[0010] Atsushi Mori et al. (Journal of Applied Polymer Science, 2004, 91(5): 2739-3420) found in their study of wood melamine adhesives that the bonding strength increases with the degree of acetylation of AA-PVA. Patent US20070148483A1 describes how the use of AA-PVA with a crosslinking agent as a polarizer adhesive layer can effectively improve the adhesive durability of polarizers, but the improvement in durability is still affected by the crosslinking agent. Patent US20050197441A1 also describes an aqueous emulsion prepared by using AA-PVA and acrylic monomers together, which can be used as an adhesive for particleboard, thereby effectively improving the stability of the adhesive. Patent CN202311454758.8 describes a vinyl acetate-ethylene copolymer emulsion and its adhesive, which improves the performance of the emulsion by adding different polymer monomers to make it act as a protective colloid.

[0011] Therefore, acetylation modification of PVA to enhance the crosslinking of its active sites with the adhesive substrate can improve the performance of the adhesive, including bond strength, solvent resistance and water resistance.

[0012] The acetylacetamide group possesses both the β-dicarbonyl active structure of the acetoacetyl group (i.e., a highly reactive ketone carbonyl group and a methylene group) and better hydrolysis resistance compared to the acetoacetyl ester group. However, because the amide group does not readily react directly with the hydroxyl groups on PVA, it has not been used in the acetylation modification of PVA. Therefore, this invention uses a triazine group as a bridging group to introduce the acetylacetamide group into PVA through chemical bonds, thus preparing a modified PVA (AAM-PVA) containing a diacetylacetamide group. Summary of the Invention

[0013] The technical problem to be solved by this invention is to provide a hydrolysis-resistant acetylacetamide-modified polyvinyl alcohol and its preparation method. The preparation method is simple, efficient, exhibits good hydrolysis resistance, and can introduce more acetylacetamide groups. When the hydrolysis-resistant acetylacetamide-modified polyvinyl alcohol prepared by this invention is applied to the emulsion polymerization of PVAc as a protective colloid, it can significantly improve the strength and hydrolysis resistance of the film after emulsion formation, as well as the adhesive properties of the downstream PVAc emulsion adhesive.

[0014] To address the aforementioned technical problems, embodiments of the present invention provide a hydrolysis-resistant acetylacetamide-modified polyvinyl alcohol having the structure shown in Formula I:

[0015]

[0016] Wherein, R is a straight-chain alkyl group having 2-3 carbon atoms;

[0017] Both x and y are integers, with x ranging from 200 to 2500 and y ranging from 20 to 400; the value of z is related to the grafting rate.

[0018] The raw materials for preparing the hydrolysis-resistant acetoacetamide-modified polyvinyl alcohol include: diketene, cyanuric chloride, polyvinyl alcohol (PVA), tertiary amine compounds, and alkanolamine compounds.

[0019] Preferably, the tertiary amine compound is one of trimethylamine, N,N-di-isopropylethylamine (DIEA), triethylamine, and dicyclohexylmethylamine.

[0020] Preferably, the alkanolamine compound is one of ethanolamine and n-propanolamine.

[0021] Preferably, the raw material used in the preparation is PVA with a degree of polymerization of 300-2400, a degree of hydrolysis of 85-99.9 mol%, and a particle size of 120-300 mesh.

[0022] This invention also provides a method for preparing hydrolysis-resistant acetylacetamide-modified polyvinyl alcohol, comprising the following steps:

[0023] S1. In a first polar solvent, diketene and an alcohol amine compound are reacted at -5 to 0°C to prepare an acetylacetylamine compound;

[0024] S2. In a second polar solvent, the acetoacetolamine compound prepared in step S1 is reacted with cyanuric chloride by heating to prepare cyanuric chloride acetoacetamide compound;

[0025] S3. The trichlorocyanuric acid acetoacetamide compound prepared in step S2 reacts with the tertiary amine compound and polyvinyl alcohol in a third polar solvent to generate hydrolysis-resistant acetoacetamide-modified polyvinyl alcohol.

[0026] In step S1, the first polar solvent is one of acetone, tetrahydrofuran, and acetonitrile; the alkanolamine compound is one of ethanolamine and n-propanolamine.

[0027] In step S2, the heating temperature is 65°C; the second polar solvent is one of acetone, tetrahydrofuran, and acetonitrile.

[0028] In step S3, the degree of polymerization of the polyvinyl alcohol is 300-2400, the degree of alcoholysis is 85-99.9 mol%, and the particle size is 120-300 mesh; the third polar solvent is one of acetone, DMF, and acetonitrile; and the alkanolamine compound is one of ethanolamine and n-propanolamine.

[0029] The beneficial effects of the above technical solution of the present invention are as follows:

[0030] 1. This invention provides an acetylacetamide-modified polyvinyl alcohol (AAM-PVA) that uses triazine as a bridging group, so that each equivalent of PVA can be linked to two molecules of acetylacetamide groups, while retaining the active acetylacetamide group, and improving hydrolysis resistance compared to acetylacetamide.

[0031] 2. The acetylacetamide-modified polyvinyl alcohol (AAM-PVA) with Formula I provided by this invention has better water resistance than ordinary acetylated polyethylene (AA-PVA). When AAM-PVA of this invention is used as a protective colloid for polyvinyl acetate (PVAc) emulsion polymerization, it is easier to undergo grafting reaction with crosslinking agents, thereby increasing the grafting rate of AA-PVA. This improves the water resistance of PVAc emulsion adhesives while enhancing the tensile strength and stability of the adhesives.

[0032] 3. The AAM-PVA with Formula I structure provided by this invention has a simple synthesis procedure and high reaction yield; moreover, its structure is novel and has not been reported before. This is of great significance for broadening the types of protective colloids for PVAc emulsion polymerization and their subsequent industrial applications in adhesives. Attached Figure Description

[0033] Figure 1 The N-(hydroxyethyl)acetylacetamide in Example 1 of this invention 1 H NMR spectrum;

[0034] Figure 2 The 3,5-bis[acetylacetamidoethoxy]monochlorotriazine in Example 1 of this invention 1 H NMR spectrum;

[0035] Figure 3 The 3,5-bis[acetylacetamidoethoxy]triazine-modified PVA (AA) in Example 1 of this invention et -M-PVA) 1 H NMR spectrum;

[0036] Figure 4 AA in Embodiment 1 of the present invention et Infrared spectrum of M-PVA;

[0037] Figure 5 AA in Embodiment 1 of the present invention et TG spectrum of M-PVA. Detailed Implementation

[0038] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0039] This invention provides a hydrolysis-resistant acetylacetamide-modified polyvinyl alcohol having the structure shown in Formula I:

[0040]

[0041] Wherein, R is a straight-chain alkyl group having 2-3 carbon atoms;

[0042] Both x and y are integers, with x ranging from 200 to 2500 and y ranging from 20 to 400; the value of z is related to the grafting rate.

[0043] The raw materials for preparing the hydrolysis-resistant acetoacetamide-modified polyvinyl alcohol include: diketene, cyanuric chloride, polyvinyl alcohol (PVA), tertiary amine compounds, and alkanolamine compounds.

[0044] Preferably, the tertiary amine compound is one of trimethylamine, N,N-diisopropylethylamine (DIEA), triethylamine, and dicyclohexylmethylamine. The alkanolamine compound is one of ethanolamine and n-propanolamine. The raw material used in the preparation is PVA with a degree of polymerization of 300-2400, a degree of alcoholysis of 85-99.9 mol%, and a particle size of 120-300 mesh.

[0045] This invention also provides a method for preparing hydrolysis-resistant acetylacetamide-modified polyvinyl alcohol, comprising the following steps:

[0046] S1. In a first polar solvent, diketene and an alkanolamine compound react at -5 to 0°C to prepare an acetoacetyl alcoholamine compound. In this step, the first polar solvent is one of acetone, tetrahydrofuran, and acetonitrile; the alkanolamine compound is one of ethanolamine and n-propanolamine. The detailed steps of step S1 are as follows:

[0047] Diketene and an alkanolamine compound were reacted in a first polar solvent at a controlled temperature of 0°C. After standing, the solvent was removed by rotary evaporation, vacuum distillation, and vacuum drying, finally yielding the first product: N-(hydroxyalkyl)acetylacetamide, with the structure shown in Formula II.

[0048]

[0049] The reaction equation is as follows:

[0050]

[0051] Wherein, R is a straight-chain alkyl group with 2-3 carbon atoms.

[0052] The alkanolamine is ethanolamine or n-propanolamine, preferably ethanolamine.

[0053] The first polar solvent includes, but is not limited to, acetone, tetrahydrofuran, and acetonitrile, with acetonitrile being preferred.

[0054] The reaction temperature is below 0°C, preferably -5 to 0°C.

[0055] The settling time after the reaction is 6-18 hours, preferably 12 hours.

[0056] The molar ratio of diketene to alkanolamine is 1:1.1-1:1.4, preferably 1:1.2.

[0057] The molar ratio of diketene to acetonitrile is 1:1.4-1:1.6, preferably 1:1.5.

[0058] S2. In a second polar solvent, the acetoacetylamine compound prepared in step S1 is reacted with cyanuric chloride under heating to prepare cyanuric chloride acetoacetamide compound; in this step, the heating temperature is 65℃; the second polar solvent is one of acetone, tetrahydrofuran, and acetonitrile. The detailed steps of step S2 are as follows:

[0059] The N-(hydroxyalkyl)acetylacetamide prepared in step S1, as shown in Formula II, is reacted with cyanuric chloride in a second polar solvent by heating. The solvent is then removed by rotary evaporation, vacuum distillation, and vacuum drying to finally generate the second product: 3,5-bis[acetylacetamidoalkoxy]monochlorotriazine, with the structure shown in Formula III.

[0060]

[0061] The reaction equation is as follows:

[0062]

[0063] Wherein, R is a straight-chain alkyl group with 2-3 carbon atoms.

[0064] The N-(hydroxyalkyl)acetylacetamide is N-(hydroxyethyl)acetylacetamide or N-(hydroxypropyl)acetylacetamide, preferably N-(hydroxyethyl)acetylacetamide.

[0065] The second polar solvent includes, but is not limited to, acetone, tetrahydrofuran, and acetonitrile, with acetonitrile being preferred.

[0066] The reaction temperature is between 50-70℃, preferably 65℃.

[0067] The reaction time is 3 hours.

[0068] The molar ratio of cyanuric chloride to N-(hydroxyalkyl)acetylacetamide is 1:2.

[0069] S3. The cyanochloroacetylacetamide compound prepared in step S2 reacts with a tertiary amine compound and polyvinyl alcohol in a third polar solvent to generate hydrolysis-resistant acetylacetamide-modified polyvinyl alcohol. In this step, the degree of polymerization of the polyvinyl alcohol is 300-2400, the degree of alcoholysis is 85-99.9 mol%, and the particle size is 120-300 mesh; the third polar solvent is one of acetone, DMF, and acetonitrile. The detailed steps of step S3 are as follows:

[0070] The 3,5-bis[acetylacetamidoalkoxy]monochlorotriazine and tertiary amine compound prepared in step S2, and PVA, are heated and reacted in a third polar solvent under alkaline conditions. The solvent is then removed by washing with alcohol, rotary evaporation, vacuum distillation, and vacuum drying, finally yielding a PVA product modified with bisacetamido groups (AAM-PVA), as shown in Formula I.

[0071]

[0072] The reaction equation is as follows:

[0073]

[0074] Wherein, R is a straight-chain alkyl group with 2-3 carbon atoms.

[0075] Both x and y are integers, with x ranging from 200 to 2500 and y ranging from 20 to 400. The specific value of z is related to its subsequent grafting rate, and the specific range is not listed here.

[0076] The raw material PVA has a degree of polymerization of 300-2400 and a degree of alcoholysis of 85-99.9 mol%. Preferably, the degree of polymerization is 500-2000 and the degree of alcoholysis is 95-99 mol%.

[0077] The molar ratio of 3,5-bis[acetylacetamoxy]monochlorotriazine shown in Formula III to the tertiary amine compound is 1:1.

[0078] The molar ratio of 3,5-bis[acetylacetamidoalkoxy]monochlorotriazine shown in Formula III to the base is 1:1.

[0079] The mass ratio of 3,5-bis[acetylacetamidoalkoxy]monochlorotriazine shown in Formula III to PVA is 1:1-4:1, preferably 2:1.

[0080] The catalysts include, but are not limited to, trimethylamine, N,N-diisopropylethylamine (DIEA), triethylamine, dicyclohexylmethylamine, and other commonly used tertiary amines for preparing quaternary ammonium salts, with N,N-diisopropylethylamine being preferred.

[0081] The average particle size of the raw material PVA is between 120 mesh and 300 mesh, preferably 200 mesh.

[0082] The organic solvents include, but are not limited to, acetone, acetonitrile, and DMF, with acetonitrile being preferred.

[0083] The alkali may be any one or more combinations of sodium hydroxide, potassium hydroxide, potassium carbonate, or sodium carbonate, preferably sodium hydroxide.

[0084] The reaction temperature is 75-90℃, preferably 85℃.

[0085] The reaction time is 3 hours.

[0086] The washing process of the product uses anhydrous methanol as the washing solvent; the equipment used is a container equipped with heating and stirring, such as various mixers or reaction vessels.

[0087] The drying process of the product has a drying temperature of 40-70℃, a drying pressure of -0.2-1MPa, and a drying time of 1-6h. The preferred drying temperature is 45-50℃, the preferred drying pressure is -0.1-0MPa, and the preferred drying time is 4h.

[0088] To further illustrate the technical solution of the present invention, the following embodiments are provided.

[0089] Example 1

[0090] (1-a) Preparation of N-(hydroxyethyl)acetylacetamide

[0091] Diketene (1.86 g, 0.022 mol, 0.05 eq) and acetonitrile (35.24 mL) were added to a 500 mL four-necked flask. While stirring thoroughly, the temperature inside the flask was maintained between -5°C and 0°C. Then, diketene (35.2 g, 0.418 mol, 0.95 eq) and ethanolamine (31.44 g, 0.51 mol, 1.2 eq) were added separately to two separatory funnels. Diketene was added dropwise at a rate of 220 g / h, and ethanolamine at a rate of 196.5 g / h, for a total of four hours. The entire dropwise reaction was carried out in a low-temperature constant-temperature circulating bath, maintaining the temperature inside the flask at -5°C to 0°C throughout. After the reaction was complete, the temperature was raised to room temperature, and after standing for 12 hours, the reaction solution was subjected to vacuum rotary evaporation to remove the solvent acetonitrile, and then dried in a vacuum drying oven. N-(hydroxyethyl)acetylacetamide, designated 1-1a, with the structure shown in Formula IV, was obtained in 90% yield. 1 H NMR (400MHz, CDCl3) δ7.44 (s, 1H), 3.79-3.54 (m, 2H), 3.45-3.37 (m, 4H), 2.26 (s, 3H).

[0092]

[0093] (1-b) Preparation of 3,5-bis[acetylacetamidoethoxy]monochlorotriazine

[0094] Cyanuric chloride (5.96 g, 0.04 mol, 1 eq) and acetonitrile (200 mL) were added to a 500 mL four-necked flask and stirred thoroughly until the cyanuric chloride was completely dissolved in the acetonitrile, and the solution became clear and transparent. Then, N-(hydroxyethyl)acetylacetamide (11.61 g, 0.08 mol, 2 eq) and Na₂CO₃ (8.4 g, 0.08 mol, 2 eq) prepared in Example 1 (1-a) were also added to the 500 mL four-necked flask, and the mixture was stirred and heated to 65 °C for 3 h. After the reaction was complete, the solid and liquid were separated by vacuum filtration. The reaction solution was then subjected to vacuum rotary evaporation to remove the solvent acetonitrile, and then dried in a vacuum drying oven. 3,5-bis[acetylacetamidoethoxy]monochlorotriazine, designated 1-2b, with the structure of formula V, was obtained in 85% yield. 1 H NMR (400MHz, DMSO-d6) δ8.15 (s, 1H), 3.40 (t, J=6.0Hz, 2H), 3.12 (q, J=5.8Hz, 4H), 2.12 (s, 3H).

[0095]

[0096] (1-c) Preparation of AA et M-PVA

[0097] In a 250 mL four-necked flask, 11.32 g (0.5 eq) of 200-mesh 9905 PVA (99% degree of alcoholysis, 500 degree of polymerization), 70 mL of acetonitrile, 25.81 g (0.1 mol, 1 eq) of 3,5-bis[acetylacetamidoethoxy]monochlorotriazine prepared in Example 1 (1-b), 12.93 g (0.1 mol, 1 eq) of DIEA, and 4 g (0.1 mol, 1 eq) of NaOH were added. The mixture was stirred thoroughly and heated to 85 °C for 3 h. After the reaction was complete, the solid and liquid were separated by vacuum filtration. The acetonitrile solvent was removed by vacuum rotary evaporation of the reaction solution, and then the solution was dried in a vacuum drying oven to obtain AA. et M-PVA, numbered 1-3c, has the structure shown in Formula VI, with a yield of 97% and a grafting rate of 10%.

[0098]

[0099] in, Figure 1 The N-(hydroxyethyl)acetylacetamide in Example 1 of this invention 1 H NMR spectrum; Figure 2The 3,5-bis[acetylacetamidoethoxy]monochlorotriazine in Example 1 of this invention 1 H NMR spectrum; Figure 3 The 3,5-bis[acetylacetamidoethoxy]triazine-modified PVA (AA) in Example 1 of this invention et M-PVA) 1 H NMR spectrum; Figure 4 AA in Embodiment 1 of the present invention et Infrared spectrum of M-PVA; Figure 5 AA in Embodiment 1 of the present invention et TG spectrum of M-PVA.

[0100] Example 2

[0101] (2-a) Preparation of N-(hydroxyethyl)acetylacetamide

[0102] Diketene (1.86 g, 0.022 mol, 0.05 eq) and acetonitrile (32.89 mL) were added to a 500 mL four-necked flask. While stirring thoroughly, the temperature inside the flask was maintained between -5 and 0 °C. Then, diketene (35.2 g, 0.418 mol, 0.95 eq) and ethanolamine (26.2 g, 0.425 mol, 1 eq) were added separately to two separatory funnels. Diketene was added dropwise at a rate of 220 g / h, and ethanolamine at a rate of 196.5 g / h, for a total of four hours. The entire dropwise reaction was carried out in a low-temperature constant-temperature circulating bath, maintaining the temperature inside the flask at -5 to 0 °C throughout. After the reaction was complete, the temperature was raised to room temperature, and after standing for 6 hours, the reaction solution was subjected to vacuum rotary evaporation to remove the solvent acetonitrile, and then dried in a vacuum drying oven. N-(hydroxyethyl)acetylacetamide, designated 2-1a, was obtained, with a yield of 85%.

[0103] (2-b) Preparation of 3,5-bis[acetylacetamidoethoxy]monochlorotriazine

[0104] Cyanuric chloride (5.96 g, 0.04 mol, 1 eq) and acetonitrile (200 mL) were added to a 500 mL four-necked flask and stirred thoroughly until the cyanuric chloride was completely dissolved in the acetonitrile, and the solution became clear and transparent. Then, N-(hydroxyethyl)acetylacetamide (11.61 g, 0.08 mol, 2 eq) and Na₂CO₃ (8.4 g, 0.08 mol, 2 eq) prepared in Example 2 (2-a) were also added to the 500 mL four-necked flask, and the mixture was stirred and heated to 50 °C for 3 h. After the reaction was complete, the solid and liquid were separated by vacuum filtration. The reaction solution was then subjected to vacuum rotary evaporation to remove the solvent acetonitrile, and then dried in a vacuum drying oven. 3,5-bis[acetylacetamidoethoxy]monochlorotriazine was obtained, designated 2-2b, with a yield of 83%.

[0105] (2-c) Preparation of AA et M-PVA

[0106] In a 250 mL four-necked flask, 25.81 g (1 eq) of 200-mesh 9905 PVA (99% degree of alcoholysis, 500 degree of polymerization), 50 mL of acetone, 25.81 g (0.1 mol, 1 eq) of 3,5-bis[acetylacetamamidoethoxy]monochlorotriazine prepared in Example 2 (2-b), 12.93 g (0.1 mol, 1 eq) of DIEA, and 5.6 g (0.1 mol, 1 eq) of KOH were added. The mixture was stirred thoroughly and heated to 75 °C for 3 h. After the reaction was complete, the solid and liquid were separated by vacuum filtration. The acetone solvent was removed by vacuum rotary evaporation of the reaction solution, and then the solution was dried in a vacuum drying oven to obtain AA. et M-PVA, numbered 2-3c, yield 93%, grafting rate 7.3%.

[0107] Example 3

[0108] (3-a) Preparation of N-(hydroxyethyl)acetylacetamide

[0109] Diketene (1.86 g, 0.022 mol, 0.05 eq) and acetonitrile (37.59 mL) were added to a 500 mL four-necked flask. While stirring thoroughly, the temperature inside the flask was maintained between -5 and 0 °C. Then, diketene (35.2 g, 0.418 mol, 0.95 eq) and ethanolamine (36.68 g, 0.595 mol, 1.4 eq) were added separately to two separatory funnels. Diketene was added dropwise at a rate of 220 g / h, and ethanolamine at a rate of 196.5 g / h, for a total of four hours. The entire dropwise reaction was carried out in a low-temperature constant-temperature circulating bath, maintaining the temperature inside the flask at -5 to 0 °C throughout. After the reaction was complete, the temperature was raised to room temperature, and after standing for 18 hours, the reaction solution was subjected to vacuum rotary evaporation to remove the solvent acetonitrile, and then dried in a vacuum drying oven. N-(hydroxyethyl)acetylacetamide was obtained, designated 3-1a, with a yield of 87%.

[0110] (3-b) Preparation of 3,5-bis[acetylacetamidoethoxy]monochlorotriazine

[0111] Cyanuric chloride (5.96 g, 0.04 mol, 1 eq) and acetonitrile (200 mL) were added to a 500 mL four-necked flask and stirred thoroughly until the cyanuric chloride was completely dissolved in the acetonitrile, and the solution became clear and transparent. Then, N-(hydroxyethyl)acetylacetamide (11.61 g, 0.08 mol, 2 eq) and Na₂CO₃ (8.4 g, 0.08 mol, 2 eq) prepared in Example 3 (3-a) were also added to the 500 mL four-necked flask, and the mixture was stirred and heated to 70 °C for 3 h. After the reaction was complete, the solid and liquid were separated by vacuum filtration. The reaction solution was then subjected to vacuum rotary evaporation to remove the solvent acetonitrile, and then dried in a vacuum drying oven. 3,5-bis[acetylacetamidoethoxy]monochlorotriazine was obtained, designated 3-2b, with a yield of 83%.

[0112] (3-c) Preparation of AA et M-PVA

[0113] In a 250 mL four-necked flask, 5.2 g (0.25 eq) of 200-mesh 9905 PVA (99% degree of alcoholysis, 500 degree of polymerization), 65 mL of DMF, 25.81 g (0.1 mol, 1 eq) of 3,5-bis[acetylacetamidoethoxy]monochlorotriazine prepared in Example 3 (3-b), 12.93 g (0.1 mol, 1 eq) of DIEA, and 10.5 g (0.1 mol, 1 eq) of Na₂CO₃ were added and stirred thoroughly. The mixture was heated to 90 °C and reacted for 3 h. After the reaction was complete, the solid and liquid were separated by vacuum filtration. The solvent DMF was removed by vacuum rotary evaporation of the reaction solution, and then the solution was dried in a vacuum drying oven to obtain AA. et M-PVA, designated 3-3c, yield 90%, grafting rate 6.9%.

[0114] Example 4

[0115] (4-a) Preparation of N-(hydroxyethyl)acetylacetamide

[0116] Diketene (1.86 g, 0.022 mol, 0.05 eq) and acetone (38.33 mL) were added to a 500 mL four-necked flask. While stirring thoroughly, the temperature inside the flask was maintained between -10 and -5 °C. Then, diketene (35.2 g, 0.418 mol, 0.95 eq) and ethanolamine (31.44 g, 0.51 mol, 1.2 eq) were added separately to two separatory funnels. Diketene was added dropwise at a rate of 220 g / h, and ethanolamine at a rate of 196.5 g / h, for a total of four hours. The entire dropwise reaction was carried out in a low-temperature constant-temperature circulating bath, maintaining the temperature inside the flask between -10 and -5 °C at all times. After the reaction was complete, the temperature was raised to room temperature, and after standing for 12 hours, the acetone solvent was removed by vacuum rotary evaporation, and then the reaction solution was dried in a vacuum drying oven. N-(hydroxyethyl)acetylacetamide was obtained, designated 4-1a, in 84% yield.

[0117] (4-b) Preparation of 3,5-bis[acetylacetamidoethoxy]monochlorotriazine

[0118] Cyanuric chloride (5.96 g, 0.04 mol, 1 eq) and acetone (160 mL) were added to a 500 mL four-necked flask and stirred thoroughly until the cyanuric chloride was completely dissolved in the acetone, and the solution became clear and transparent. Then, N-(hydroxyethyl)acetylacetamide (11.61 g, 0.08 mol, 2 eq) and Na₂CO₃ (8.4 g, 0.08 mol, 2 eq) prepared in Example 4 (4-a) were also added to the 500 mL four-necked flask, and the mixture was stirred and heated to 65 °C for 3 h. After the reaction was complete, the solid and liquid were separated by vacuum filtration. The reaction solution was then subjected to vacuum rotary evaporation to remove the solvent acetone, and then dried in a vacuum drying oven to obtain 3,5-bis[acetylacetamidoethoxy]monochlorotriazine, designated 4-2b, with a yield of 84%.

[0119] (4-c) Preparation of AA et M-PVA

[0120] In a 250 mL four-necked flask, 11.32 g (0.5 eq) of PVA (85% degree of hydrolysis, 300 degree of polymerization) of 120 mesh 8503, acetonitrile (70 mL), 25.81 g (0.1 mol, 1 eq) of 3,5-bis[acetylacetamidoethoxy]monochlorotriazine prepared in Example 4 (4-b), trimethylamine (5.91 g, 0.1 mol, 1 eq), NaOH (2 g, 0.05 mol, 0.5 eq), and Na₂CO₃ (5.25 g, 0.05 mol, 0.5 eq) were added and stirred thoroughly. The mixture was heated to 85 °C and reacted for 3 h. After the reaction was completed, the solid and liquid were separated by suction filtration. The reaction solution was then subjected to vacuum rotary evaporation to remove the solvent acetonitrile, and then dried in a vacuum drying oven to obtain AA. etM-PVA, designated 4-3c, yield 80%, grafting rate 4.3%.

[0121] Example 5

[0122] (5-a) Preparation of N-(hydroxyethyl)acetylacetamide

[0123] Diketene (1.86 g, 0.022 mol, 0.05 eq) and acetone (35.78 mL) were added to a 500 mL four-necked flask. While stirring thoroughly, the temperature inside the flask was maintained between -5 and 0 °C. Then, diketene (35.2 g, 0.418 mol, 0.95 eq) and ethanolamine (31.44 g, 0.51 mol, 1.2 eq) were added separately to two separatory funnels. Diketene was added dropwise at a rate of 220 g / h, and ethanolamine at a rate of 196.5 g / h, for a total of four hours. The entire dropwise reaction was carried out in a low-temperature constant-temperature circulating bath, maintaining the temperature inside the flask at -5 to 0 °C throughout. After the reaction was complete, the temperature was raised to room temperature, and after standing for 18 hours, the acetone solvent was removed by vacuum rotary evaporation, and then the mixture was dried in a vacuum drying oven. N-(hydroxyethyl)acetylacetamide was obtained, designated 5-1a, with a yield of 89%.

[0124] (5-b) Preparation of 3,5-bis[acetylacetamidoethoxy]monochlorotriazine

[0125] Cyanurium chloride (5.96 g, 0.04 mol, 1 eq) and acetone (160 mL) were added to a 500 mL four-necked flask and stirred thoroughly until the cyanurium chloride was completely dissolved in tetrahydrofuran, and the solution became clear and transparent. Then, N-(hydroxyethyl)acetylacetamide (11.61 g, 0.08 mol, 2 eq) and Na₂CO₃ (8.4 g, 0.08 mol, 2 eq) prepared in Example 5 (5-a) were also added to the 500 mL four-necked flask, and the mixture was stirred and heated to 50 °C for 3 h. After the reaction was complete, the solid and liquid were separated by vacuum filtration, and the solvent acetone was removed by vacuum rotary evaporation of the reaction solution, followed by drying in a vacuum drying oven. 3,5-bis[acetylacetamidoethoxy]monochlorotriazine was obtained, designated 5-2b, with a yield of 81%.

[0126] (5-c) Preparation of AA et M-PVA

[0127] In a 250 mL four-necked flask, 11.32 g (0.5 eq) of 300-mesh 9510 PVA (95% degree of alcoholysis, 1000 degree of polymerization), 70 mL of acetonitrile, 25.81 g (0.1 mol, 1 eq) of 3,5-bis[acetylacetamidoethoxy]monochlorotriazine prepared in Example 5 (5-b), 12.93 g (0.1 mol, 1 eq), 2.8 g (0.05 mol, 0.5 eq) of KOH, and 5.25 g (0.05 mol, 0.5 eq) of Na₂CO₃ were added and stirred thoroughly. The mixture was heated to 85 °C and reacted for 3 h. After the reaction was complete, the solid and liquid were separated by vacuum filtration. The reaction solution was then subjected to vacuum rotary evaporation to remove the solvent acetonitrile, and then dried in a vacuum drying oven to obtain AA. et M-PVA, designated 5-3c, yield 89%, grafting rate 7.7%.

[0128] Example 6

[0129] (6-a) Preparation of N-(hydroxyethyl)acetylacetamide

[0130] Diketene (1.86 g, 0.022 mol, 0.05 eq) and acetone (40.89 mL) were added to a 500 mL four-necked flask. While stirring thoroughly, the temperature inside the flask was maintained between -15 and -10 °C. Then, diketene (35.2 g, 0.418 mol, 0.95 eq) and ethanolamine (31.44 g, 0.51 mol, 1.2 eq) were added separately to two separatory funnels. Diketene was added dropwise at a rate of 220 g / h, and ethanolamine at a rate of 196.5 g / h, for a total of four hours. The entire dropwise reaction was carried out in a low-temperature constant-temperature circulating bath, maintaining the temperature inside the flask between -15 and -10 °C at all times. After the reaction was complete, the temperature was raised to room temperature, and after standing for 6 hours, the acetone solvent was removed by vacuum rotary evaporation, and then the reaction solution was dried in a vacuum drying oven. N-(hydroxyethyl)acetylacetamide was obtained, designated 6-1a, in 83% yield.

[0131] (6-b) Preparation of 3,5-bis[acetylacetamidoethoxy]monochlorotriazine

[0132] Cyanurium chloride (5.96 g, 0.04 mol, 1 eq) and acetone (160 mL) were added to a 500 mL four-necked flask and stirred thoroughly until the cyanurium chloride was completely dissolved in tetrahydrofuran, and the solution became clear and transparent. Then, N-(hydroxyethyl)acetylacetamide (11.61 g, 0.08 mol, 2 eq) and Na₂CO₃ (8.4 g, 0.08 mol, 2 eq) prepared in Example 6 (6-a) were also added to the 500 mL four-necked flask, and the mixture was stirred and heated to 70 °C for 3 h. After the reaction was complete, the solid and liquid were separated by suction filtration, and the reaction solution was subjected to vacuum rotary evaporation to remove the solvent acetone, and then dried in a vacuum drying oven. 3,5-bis[acetylacetamidoethoxy]monochlorotriazine was obtained, designated 6-2b, with a yield of 83%.

[0133] (6-c) Preparation of AA et M-PVA

[0134] In a 250 mL four-necked flask, 11.32 g (0.5 eq) of 200-mesh 9915 PVA (99% degree of alcoholysis, 1500 degree of polymerization), 70 mL of acetonitrile, 25.81 g (0.1 mol, 1 eq) of 3,5-bis[acetylacetamidoethoxy]monochlorotriazine prepared in Example 6 (6-b), 10.19 g (0.1 mol, 1 eq), 2 g (0.05 mol, 0.5 eq) of NaOH, and 2.8 g (0.05 mol, 0.5 eq) of KOH were added. The mixture was stirred thoroughly and heated to 85 °C for 3 h. After the reaction was completed, the solid and liquid were separated by vacuum filtration. The solvent acetonitrile was removed by vacuum rotary evaporation of the reaction solution, and then the solution was dried in a vacuum drying oven to obtain AA. et M-PVA, numbered 6-3c, yield 88%, grafting rate 9.6%.

[0135] Example 7

[0136] (7-a) Preparation of N-(hydroxyethyl)acetylacetamide

[0137] Diketene (1.86 g, 0.022 mol, 0.05 eq) and tetrahydrofuran (47.59 mL) were added to a 500 mL four-necked flask. While stirring thoroughly, the temperature inside the flask was maintained between -5 and 0 °C. Then, diketene (35.2 g, 0.418 mol, 0.95 eq) and ethanolamine (31.44 g, 0.51 mol, 1.2 eq) were added separately to two separatory funnels. Diketene was added dropwise at a rate of 220 g / h, and ethanolamine at a rate of 196.5 g / h, for a total of four hours. The entire dropwise reaction was carried out in a low-temperature constant-temperature circulating bath, maintaining the temperature inside the flask at -5 to 0 °C throughout. After the reaction was complete, the temperature was raised to room temperature and allowed to stand for 12 hours. The reaction solution was then subjected to vacuum rotary evaporation to remove the solvent tetrahydrofuran, and then dried in a vacuum drying oven to obtain N-(hydroxyethyl)acetylacetamide, designated 7-1a, with a yield of 85%.

[0138] (7-b) Preparation of 3,5-bis[acetylacetamidoethoxy]monochlorotriazine

[0139] Cyanurium chloride (5.96 g, 0.04 mol, 1 eq) and tetrahydrofuran (190 mL) were added to a 500 mL four-necked flask and stirred thoroughly until the cyanurium chloride was completely dissolved in the tetrahydrofuran, and the solution became clear and transparent. Then, N-(hydroxyethyl)acetylacetamide (11.61 g, 0.08 mol, 2 eq) and Na₂CO₃ (8.4 g, 0.08 mol, 2 eq) prepared in Example 7 (7-a) were also added to the 500 mL four-necked flask, and the mixture was stirred and heated to 65 °C for 3 h. After the reaction was complete, the solid and liquid were separated by vacuum filtration. The reaction solution was then subjected to vacuum rotary evaporation to remove the solvent tetrahydrofuran, and then dried in a vacuum drying oven to obtain 3,5-bis[acetylacetamidoethoxy]monochlorotriazine, designated 7-2b, with a yield of 84%.

[0140] (7-c) Preparation of AA et M-PVA

[0141] In a 250 mL four-necked flask, 11.32 g (0.5 eq) of 200-mesh 9920 PVA (99% degree of alcoholysis, 2000 degree of polymerization), 70 mL of acetonitrile, 25.81 g (0.1 mol, 1 eq) of 3,5-bis[acetylacetamidoethoxy]monochlorotriazine prepared in Example 7 (7-b), 19.53 g (0.1 mol, 1 eq) of dicyclohexylmethylamine, and 4 g (0.1 mol, 1 eq) of NaOH were added. The mixture was stirred thoroughly and heated to 85 °C for 3 h. After the reaction was completed, the solid and liquid were separated by vacuum filtration. The acetonitrile solvent was removed by vacuum rotary evaporation of the reaction solution, and then dried in a vacuum drying oven to obtain AA. etM-PVA, designated 7-3c, yield 88%, grafting rate 9.2%.

[0142] Example 8

[0143] (8-a) Preparation of N-(hydroxyethyl)acetylacetamide

[0144] Diketene (1.86 g, 0.022 mol, 0.05 eq) and tetrahydrofuran (44.42 mL) were added to a 500 mL four-necked flask. While stirring thoroughly, the temperature inside the flask was maintained between -5 and 0 °C. Then, diketene (35.2 g, 0.418 mol, 0.95 eq) and ethanolamine (31.44 g, 0.51 mol, 1.2 eq) were added separately to two separatory funnels. Diketene was added dropwise at a rate of 220 g / h, and ethanolamine at a rate of 196.5 g / h, for a total of four hours. The entire dropwise reaction was carried out in a low-temperature constant-temperature circulating bath, maintaining the temperature inside the flask at -5 to 0 °C throughout. After the reaction was complete, the temperature was raised to room temperature and allowed to stand for 12 hours. The reaction solution was then subjected to vacuum rotary evaporation to remove the solvent tetrahydrofuran, and then dried in a vacuum drying oven to obtain N-(hydroxyethyl)acetylacetamide, designated 8-1a, with a yield of 84%.

[0145] (8-b) Preparation of 3,5-bis[acetylacetamidoethoxy]monochlorotriazine

[0146] Cyanurium chloride (5.96 g, 0.04 mol, 1 eq) and tetrahydrofuran (190 mL) were added to a 500 mL four-necked flask and stirred thoroughly until the cyanurium chloride was completely dissolved in the tetrahydrofuran, and the solution became clear and transparent. Then, N-(hydroxyethyl)acetylacetamide (11.61 g, 0.08 mol, 2 eq) and Na₂CO₃ (8.4 g, 0.08 mol, 2 eq) prepared in Example 8 (8-a) were also added to the 500 mL four-necked flask, and the mixture was stirred and heated to 50 °C for 3 h. After the reaction was complete, the solid and liquid were separated by vacuum filtration. The reaction solution was then subjected to vacuum rotary evaporation to remove the solvent tetrahydrofuran, and then dried in a vacuum drying oven to obtain 3,5-bis[acetylacetamidoethoxy]monochlorotriazine, designated 8-2b, with a yield of 82%.

[0147] (8-c) Preparation of AA et M-PVA

[0148] In a 250 mL four-necked flask, 11.32 g (0.5 eq) of 200-mesh 9820 PVA (98% degree of alcoholysis, 2000 degree of polymerization), 70 mL of acetonitrile, 25.81 g (0.1 mol, 1 eq) of 3,5-bis[acetylacetamidoethoxy]monochlorotriazine prepared in Example 8 (8-b), 12.93 g (0.1 mol, 1 eq) of DIEA, and 4 g (0.1 mol, 1 eq) of NaOH were added. The mixture was stirred thoroughly and heated to 85 °C for 3 h. After the reaction was completed, the solid and liquid were separated by vacuum filtration. The acetonitrile solvent was removed by vacuum rotary evaporation of the reaction solution, and then dried in a vacuum drying oven to obtain AA. et M-PVA, designated 8-3c, yield 89%, grafting rate 8.4%.

[0149] Example 9

[0150] (9-a) Preparation of N-(hydroxyethyl)acetylacetamide

[0151] Diketene (1.86 g, 0.022 mol, 0.05 eq) and tetrahydrofuran (50.77 mL) were added to a 500 mL four-necked flask. While stirring thoroughly, the temperature inside the flask was maintained between -5 and 0 °C. Then, diketene (35.2 g, 0.418 mol, 0.95 eq) and ethanolamine (31.44 g, 0.51 mol, 1.2 eq) were added separately to two separatory funnels. Diketene was added dropwise at a rate of 220 g / h, and ethanolamine at a rate of 196.5 g / h, for a total of four hours. The entire dropwise reaction was carried out in a low-temperature constant-temperature circulating bath, maintaining the temperature inside the flask at -5 to 0 °C throughout. After the reaction was complete, the temperature was raised to room temperature and allowed to stand for 12 hours. The reaction solution was then subjected to vacuum rotary evaporation to remove the solvent tetrahydrofuran, and then dried in a vacuum drying oven to obtain N-(hydroxyethyl)acetylacetamide, designated 9-1a, with a yield of 84%.

[0152] (9-b) Preparation of 3,5-bis[acetylacetamidoethoxy]monochlorotriazine

[0153] In a 500 mL four-necked flask, 5.96 g (0.04 mol, 1 eq) of cyanuric chloride and 190 mL of tetrahydrofuran were added and stirred thoroughly until the cyanuric chloride was completely dissolved in the tetrahydrofuran, and the solution became clear and transparent. Then, N-(hydroxyethyl)acetylacetamide (11.61 g, 0.08 mol, 2 eq) and Na₂CO₃ (8.4 g, 0.08 mol, 2 eq) prepared in Example 9 (9-a) were also added to the 500 mL four-necked flask, and the mixture was stirred and heated to 70 °C for 3 h. After the reaction was complete, the solid and liquid were separated by vacuum filtration. The reaction solution was then subjected to vacuum rotary evaporation to remove the solvent tetrahydrofuran, and then dried in a vacuum drying oven to obtain 3,5-bis[acetylacetamidoethoxy]monochlorotriazine, designated 9-2b, with a yield of 83%.

[0154] (9-c) Preparation of AA et M-PVA

[0155] In a 250 mL four-necked flask, 11.32 g (0.5 eq) of 200-mesh 9924 PVA (99% degree of alcoholysis, 2400 degree of polymerization), 70 mL of acetonitrile, 25.81 g (0.1 mol, 1 eq) of 3,5-bis[acetylacetamidoethoxy]monochlorotriazine prepared in Example 9 (9-b), 12.93 g (0.1 mol, 1 eq) of DIEA, and 4 g (0.1 mol, 1 eq) of NaOH were added. The mixture was stirred thoroughly and heated to 85 °C for 3 h. After the reaction was completed, the solid and liquid were separated by vacuum filtration. The solvent acetonitrile was removed by vacuum rotary evaporation of the reaction solution, and then the solution was dried in a vacuum drying oven to obtain AA. et M-PVA, designated 9-3c, yield 85%, grafting rate 6.8%.

[0156] Example 10

[0157] (10-a) Preparation of N-(hydroxypropyl)acetylacetamide

[0158] The preparation process was the same as step (1-a) of Example 1, except that the alkanolamine compound used was n-propanolamine. The result was N-(hydroxypropyl)acetylacetamide, numbered 10-1a, with the structure shown in Formula VII, and a yield of 89%.

[0159]

[0160] (10-b) Preparation of 3,5-bis[acetylacetamidopropoxy]monochlorotriazine

[0161] Except for the use of product 10-1a obtained in Example 10 (10-a) for the alkanolamine compound, the preparation process was the same as step (1-b) of Example 1, yielding 3,5-bis[acetylacetamidopropoxy]monochlorotriazine, designated 10-2b, with the structure of formula (VIII), in a yield of 84%.

[0162]

[0163] (10-c) Preparation of AA pr M-PVA

[0164] The preparation process was identical to step (1-c) of Example 1, except that the alkanolamine compound used was product 10-2b obtained in Example 10 (10-b). The result was AA. pr M-PVA, designated 10-3c, has the structure shown in Formula IX, with a yield of 92% and a grafting rate of 6.5%.

[0165]

[0166] Comparative Example 1

[0167] Choose PVA series products from China Chuanwei Chemical Co., Ltd., model 9905 (degree of hydrolysis 99%, degree of polymerization 500, viscosity 5-6.5 MPa.s, volatile content max 5%, pH=5-7).

[0168] Comparative Example 2

[0169] Choose GOHSENX from Mitsubishi Chemical Company, Japan. TM Z Series product, model Z-200 (degree of hydrolysis 99%, degree of polymerization 500, viscosity 11.5-14 MPa.s, volatile content max 5%, pH=3.5-5).

[0170] Comparative Example 3

[0171] Choose GOHSENX from Mitsubishi Chemical Company, Japan. TM Z Series product, model Z-210 (degree of hydrolysis 95-97%, degree of polymerization 500, viscosity 11.5-15MPa.s, volatile content max 5%, pH=4-5.3).

[0172] Performance testing

[0173] Test 1: Performance testing as a protective colloid in PVAc emulsion polymerization

[0174] The main relevant indicators of the PVAc emulsions prepared using products 1-3c, 10-3c, and Comparative Examples 1-3 are shown in Table 1. (There are no special requirements for the preparation of PVAc emulsions. You only need to choose one commercially available product and replace the protective colloidal PVA or AA-PVA with the products 1-3c, 10-3c, and Comparative Examples 1-3, while keeping other conditions unchanged. A commonly used laboratory preparation method is provided here as shown in Example 1.)

[0175] Example 1

[0176] 1. Dissolve polyvinyl alcohol

[0177] In a 250 mL four-necked reaction flask equipped with an electric stirrer, a spherical condenser, a dropping funnel, a thermometer, and a nitrogen delivery tube, add 3 g of 9905PVA (degree of alcoholysis 99%, degree of polymerization 500) from Comparative Example 1 and 50 mL of deionized water, and start stirring; gradually raise the water bath temperature to 80 °C and keep it constant until all polyvinyl alcohol is dissolved.

[0178] 2. Preparation of solution

[0179] Weigh 0.3g of ammonium persulfate, dissolve it in 3mL of water to prepare a 10% solution.

[0180] 3. Aggregation

[0181] (1) Add 1g of emulsifier OP-10 to the dissolved polyvinyl alcohol solution, stir and heat to 60℃.

[0182] (2) Add 11 mL of vinyl acetate and 1 / 4 (about 1.2 mL) of the prepared ammonium persulfate solution to the above emulsion; purge the air with nitrogen and keep the temperature at 60-65℃ (reflux) for reaction.

[0183] (3) When the temperature rises to 80-83℃, the reflux gradually decreases. Start by slowly adding 43mL of vinyl acetate using a dropping funnel to control the dropping rate so that the reaction temperature is kept between 80±2℃ and there is moderate reflux. The addition is completed in about 2 hours. During the addition of vinyl acetate, add 1.2mL of initiator solution in 3-4 portions.

[0184] (4) After the monomer is added, add the remaining initiator solution at once. When the reaction temperature rises to 90-95℃, maintain it for 0.5h and then stop the reaction.

[0185] (5) When the emulsion is cooled to 50°C, the pH is adjusted to 5-6 with 10% sodium bicarbonate solution; 5g of dibutyl phthalate is added, stirred evenly, and cooled to room temperature to obtain the product.

[0186] Table 1 shows the water resistance of the emulsion, which was tested according to GB / T 23445-2009. The tensile strength and elongation at break of the emulsion were tested, and the results are as follows:

[0187] Tensile strength test: After the emulsion is made into a film, it is tested using a universal testing machine.

[0188] The film-forming method is as follows: Weigh 5g of raw PVA (products 1-3c, 10-3c, and the products in comparative examples 1-3), add 100mL of pure water, heat to above 90℃ until completely dissolved, and prepare a 5% PVA aqueous solution. Then, in a film with dimensions of 23x17cm... 2 A PVA aqueous solution was poured onto a framed glass plate, and a film was formed using the casting method and dried at room temperature. Finally, the film was cut into strips 50 mm long and 20 mm wide and stored in a desiccator. (Tests were conducted using films with a uniform thickness of 0.05 mm.)

[0189] Tensile strength reduction rate = (untreated tensile strength - water-treated tensile strength) * 100% / untreated tensile strength.

[0190] The rate of decrease in elongation at break = (Elongation at break without treatment - Elongation at break with water treatment) * 100% / Elongation at break without treatment.

[0191] Table 1 Performance Indicators of PVAc Emulsion

[0192]

[0193] Table 1 shows that the tensile strength and elongation at break of samples prepared using products 1-3c, 10-3c, and Comparative Examples 1-3 as protective colloids all decreased to varying degrees after water treatment. Specifically, the emulsion using 1-3c as the protective colloid showed a 7% decrease in tensile strength and a 9% decrease in elongation at break; the emulsion using 10-3c showed an 8% decrease in tensile strength and an 11% decrease in elongation at break; while the emulsions prepared using PVA from Sichuan Weihua or AA-PVA from Mitsubishi Chemical Corporation of Japan showed a 9%-13% decrease in tensile strength and an 11%-22% decrease in elongation at break. This indicates that using AAM-PVA as a protective colloid can significantly improve the water resistance of the emulsion.

[0194] Test 2: Water resistance test after membrane fabrication

[0195] Film preparation: Weigh 5g of raw PVA (products 1-3c, 10-3c, and the products in comparative examples 1-3) and add 100mL of pure water. Heat to above 90℃ until completely dissolved to prepare a 5% PVA aqueous solution. Then, film with dimensions of 23x17cm... 2PVA aqueous solution was poured onto a framed glass plate, and a film was formed using the casting method and dried at room temperature. Finally, it was cut into 50mm diameter discs and stored in a desiccator. (Tests were conducted using films with a uniform thickness of 0.05mm).

[0196] Three circular membranes of 50 mm diameter each (with a uniform thickness of 0.05 mm) were selected from products 1-3c, 10-3c, and Comparative Examples 1-3. The membranes were then immersed in pure water, 0.1 mol / L NaOH solution, and 2% (volume fraction) acetic acid solution, respectively, and allowed to stand at room temperature for 24 hours. Their water resistance properties are shown in Table 2 (√ for good performance, × for poor performance, and - for average performance).

[0197] Table 2 Water resistance properties of AAM-PVA membrane

[0198] Serial Number pure water 0.1 mol / L NaOH solution 2% (volume fraction) acetic acid solution 1-3c √ √ √ 10-3c √ √ - Comparative Example 1 - × × Comparative Example 2 √ - - Comparative Example 3 √ - -

[0199] As shown in Table 2, when the products 1-3c, 10-3c and the commercial products of Comparative Examples 1-3 were made into films and tested in neutral, alkaline and acidic solutions, products 1-3c and 10-3c showed the best water resistance and also significantly improved acid and alkali resistance.

[0200] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0201] 1. This invention provides a diacetylacetamide-modified polyvinyl alcohol (AAM-PVA) that uses triazine as a bridging group, so that each equivalent of PVA can be linked to two molecules of acetylacetamide groups, while retaining the active acetylacetamide group, and improving hydrolysis resistance compared to acetylacetamide.

[0202] 2. The acetylacetamide-modified polyvinyl alcohol (AAM-PVA) with Formula I provided by this invention has better water resistance than ordinary acetylated polyethylene (AA-PVA). When AAM-PVA of this invention is used as a protective colloid for polyvinyl acetate (PVAc) emulsion polymerization, it is easier to undergo grafting reaction with crosslinking agents, thereby increasing the grafting rate of AA-PVA. This improves the water resistance of PVAc emulsion adhesives while enhancing the tensile strength and stability of the adhesives.

[0203] 3. The AAM-PVA with Formula I structure provided by this invention has a simple synthesis procedure and high reaction yield; moreover, its structure is novel and has not been reported before. This is of great significance for broadening the types of protective colloids for PVAc emulsion polymerization and their subsequent industrial applications in adhesives.

[0204] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A hydrolysis-resistant acetylacetam-modified polyvinyl alcohol, characterized in that, It has a structure as shown in Equation I: Wherein, R is a straight-chain alkyl group having 2-3 carbon atoms; Both x and y are integers, with x ranging from 200 to 2500 and y ranging from 20 to 400; the value of z is related to the grafting rate.

2. The hydrolysis-resistant acetylacetam-modified polyvinyl alcohol according to claim 1, characterized in that, The raw materials for preparing the hydrolysis-resistant acetoacetamide-modified polyvinyl alcohol include: diketene, cyanuric chloride, polyvinyl alcohol, tertiary amine compounds, and alkanolamine compounds.

3. The hydrolysis-resistant acetylacetam-modified polyvinyl alcohol according to claim 2, characterized in that, The tertiary amine compound is one of trimethylamine, N,N-diisopropylethylamine, triethylamine, and dicyclohexylmethylamine.

4. The hydrolysis-resistant acetylacetam-modified polyvinyl alcohol according to claim 2, characterized in that, The alkanolamine compound is one of ethanolamine and n-propanolamine.

5. The hydrolysis-resistant acetylacetam-modified polyvinyl alcohol according to claim 2, characterized in that, The raw material used in the preparation is PVA with a degree of polymerization of 300-2400, a degree of alcoholysis of 85-99.9 mol%, and a particle size of 120-300 mesh.

6. A method for preparing hydrolysis-resistant acetylacetam-modified polyvinyl alcohol as described in any one of claims 1-5, characterized in that, Includes the following steps: S1. In a first polar solvent, diketene and an alcohol amine compound are reacted at -5 to 0°C to prepare an acetylacetylamine compound; S2. In a second polar solvent, the acetoacetolamine compound prepared in step S1 is reacted with cyanuric chloride by heating to prepare cyanuric chloride acetoacetamide compound; S3. The trichlorocyanuric acid acetoacetamide compound prepared in step S2 reacts with the tertiary amine compound and polyvinyl alcohol in a third polar solvent to generate hydrolysis-resistant acetoacetamide-modified polyvinyl alcohol.

7. The method for preparing hydrolysis-resistant acetylacetam-modified polyvinyl alcohol according to claim 6, characterized in that, In step S1, the first polar solvent is one of acetone, tetrahydrofuran, and acetonitrile; the alkanolamine compound is one of ethanolamine and n-propanolamine.

8. The method for preparing hydrolysis-resistant acetylacetam-modified polyvinyl alcohol according to claim 6, characterized in that, In step S2, the temperature of the heating reaction is 65°C; the second polar solvent is one of acetone, tetrahydrofuran, and acetonitrile.

9. The method for preparing hydrolysis-resistant acetylacetam-modified polyvinyl alcohol according to claim 6, characterized in that, In step S3, the degree of polymerization of the polyvinyl alcohol is 300-2400, the degree of alcoholysis is 85-99.9 mol%, and the particle size is 120-300 mesh; the third polar solvent is one of acetone, DMF, and acetonitrile; and the alkanolamine compound is one of ethanolamine and n-propanolamine.

Images