Hydrolysis-resistant acetoacetamido modified polyvinyl alcohol and preparation method thereof

Abstract

The invention discloses hydrolysis-resistant acetoacetamido modified polyvinyl alcohol and a preparation method thereof, and the preparation method comprises the following steps: reacting diketene with an alcohol amine compound to generate an N-(hydroxyalkyl) acetoacetamide intermediate; then cyanuric chloride and the N-(hydroxyalkyl) acetoacetamide intermediate are subjected to a reaction, and 3, 5-bis [acetoacetamido alkoxy] monochloro-s-triazine is generated; and finally, reacting the 3, 5-bis [acetoacetamido alkoxy] monochloro-s-triazine with PVA (Polyvinyl Alcohol) in a polar solvent to generate the AAM-PVA. The prepared AAM-PVA can be used as a protective colloid for polyvinyl acetate emulsion polymerization, and the water resistance, the tensile strength and the stability of the prepared emulsion adhesive are obviously improved; the modified raw materials are cheap and easy to obtain, the preparation process is simple, the reaction conditions are mild, and no waste water or waste gas is discharged.

Description

Technical Field

[0001] The invention belongs to the field of protective colloids of emulsion polymerization, and in particular relates to hydrolysis-resistant acetoacetamide-modified polyvinyl alcohol and a preparation method thereof. Background Art

[0002] With the continuous development of social economy and the improvement of people's quality of life, people's requirements for the quantity and quality of wood are also increasing year by year. Therefore, artificial boards made of wood or other non-wood plants as raw materials and glued together by applying adhesives are playing an increasingly important role. The production of plywood is inseparable from the use of adhesives. Therefore, the performance optimization of adhesives plays a very important role in the field of wood processing.

[0003] Commonly used wood adhesives in my country mainly include phenolic, urea-formaldehyde, melamine formaldehyde, epoxy resin adhesives and polyvinyl acetate emulsion adhesives. Among them, phenolic, urea-formaldehyde and melamine formaldehyde resin adhesives are collectively referred to as "trialdehyde glue". my country's wood-based panel industrial adhesives are dominated by "trialdehyde glue" and its modified adhesives. "Trialdehyde glue" has excellent water and high temperature resistance and chemical stability. The adhesive board bonded with it has strong weather resistance and excellent processing and use stability. In addition, the raw materials of "trialdehyde glue" are widely available and low in cost, so it is widely used in the production of plywood. However, "trialdehyde glue" will release harmful gases such as formaldehyde during its production and use, polluting the air in the production workshop and housing, thereby damaging people's health. With the continuous improvement of people's environmental protection and health awareness, the existing adhesive market dominated by "trialdehyde glue" 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 organic chemical raw materials. Since 2000, the world's total vinyl acetate production capacity has exceeded 5.85 million tons. Vinyl acetate is mainly used to make polyvinyl acetate (PVAc). Vinyl acetate adhesive is a thermoplastic adhesive obtained by polymerization of vinyl acetate monomer. As early as 1912, Germany had a patent for the synthesis of vinyl acetate. It uses water as a dispersant and vinyl acetate as a monomer, and is polymerized by emulsion polymerization. Since polyvinyl acetate and its copolymers have high molecular weight, high bonding strength, wide compatibility, easy mixing with various additives, and can adjust viscosity and formulate varieties with diverse performance, it has quickly become a universal adhesive that can replace "trialdehyde glue". However, it also has many defects in its own use, such as poor water and moisture resistance, especially poor acid and alkali resistance, which hinders its complete replacement of "trialdehyde glue".

[0005] Protective colloid refers to a water-soluble polymer that can play the same or similar role as an emulsifier during the emulsion polymerization process. It is one of the important components of emulsion polymerization. Protective colloids will form a protective layer on the surface of latex particles through the effect of steric hindrance to prevent particle agglomeration, thereby reducing surface tension and stabilizing the emulsion. Adding protective colloids in the production process of polyvinyl acetate emulsion can effectively control the size distribution of latex particles and improve the stability of the emulsion. In addition, compared with ordinary emulsifiers, protective colloids can also improve the strength of the emulsion film and enhance the film's resistance to cracking. Commonly used protective colloids include polyvinyl alcohol (PVA), polyvinyl pyrrolidone and hydroxycellulose. Animal glue and gelatin and other substances can also be used as protective colloids, among which PVA is the most used and widely used protective colloid.

[0006] PVA itself is a water-soluble high molecular polymer that is non-toxic, odorless, harmless, and has good environmental affinity. At the same time, it has good density, high crystallinity, and strong adhesion. It can be used as an emulsifier stabilizer (protective colloid) for the polymerization of polyvinyl acetate emulsion (PVAc), to manufacture water-soluble adhesives, benzene solvent-resistant sealants, and thermal adhesives in thermal paper.

[0007]

[0008] In order to improve the water resistance of PVA and broaden the application field of PVA, people often use acetoacetyl to modify PVA to prepare acetoacetyl-modified polyvinyl alcohol (AA-PVA), and use it as a protective colloid in emulsions. Patents US20030186811A1, US20040209014A1, US4624985A and US 20030083200A1 introduce AA-PVA formed by introducing acetoacetyl 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 introduce that AA-PVA can be used in the adhesive of polarizers and improve the performance and service life of polarizers. However, the water resistance improved by the single acetoacetyl group modification is still not enough to fully support its application in adhesives and protective colloids, because the acetoacetyl group is easily hydrolyzed under acid and alkaline conditions, which reduces the degree of acetoacetylation in PVA, which directly affects the performance of AA-PVA, thereby reducing its ability to serve as a protective colloid in emulsion polymerization, and ultimately leads to the problem of insufficient strength, water resistance and cross-linking of the film after the emulsion is formed.

[0009]

[0010] Atsushi Mori et al. (Journal of Applied Polymer Science, 2004, 91(5): 2739-3420) found that as the degree of acetylation of AA-PVA increases, the bonding strength during bonding becomes stronger and stronger; Patent US20070148483A1 introduces that when AA-PVA is used in combination with a cross-linking agent as a polarizer bonding layer, the bonding durability of the polarizer can be effectively improved, but the durability improvement is still affected by the cross-linking agent; Patent US20050197441A1 also introduces an aqueous emulsion prepared by combining AA-PVA and acrylic acid monomers, which can be used as an adhesive for particleboard, thereby effectively improving the stability of the adhesive; Patent CN202311454758.8 introduces 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, acetoacetylation modification of PVA can improve the cross-linking of its active sites with the bonding substrate, which can improve the performance of the adhesive, including bonding strength, solubility resistance and water resistance.

[0012] The acetoacetamide group has both the β-dicarbonyl active structure of the acetoacetyl group, i.e., the ketocarbonyl group and the methylene group with high reactivity; and has better hydrolysis resistance than the acetoacetyl ester group. However, since the amide group is not easy to directly react and connect with the alcoholic hydroxyl group on PVA, it has not been used in the acetoacetylation modification of PVA. For this reason, the present invention adopts s-triazine as a bridging group, introduces the acetoacetamide group into PVA through a chemical bond, and prepares a modified PVA (AAM-PVA) containing a diacetoacetamide group. Summary of the invention

[0013] The technical problem to be solved by the present invention is to provide a hydrolysis-resistant acetoacetamide-modified polyvinyl alcohol and a preparation method thereof, wherein the preparation method has the advantages of being simple, efficient, having good hydrolysis resistance, and being able to introduce more acetoacetyl groups. When the hydrolysis-resistant acetoacetamide-modified polyvinyl alcohol prepared by the present invention is applied to the emulsion polymerization of PVAc and acts as a protective colloid of the PVAc emulsion, the strength and hydrolysis resistance of the film after the emulsion is formed and the adhesive performance of the downstream product PVAc emulsion adhesive can be significantly improved.

[0014] In order to solve the above technical problems, an embodiment of the present invention provides a hydrolysis-resistant acetoacetamide-modified polyvinyl alcohol having a structure as shown in Formula I:

[0015]

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

[0017] Both x and y are integers, x is 200-2500, y is 20-400; 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 alcohol amine compounds.

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

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

[0021] Preferably, the raw material for 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 meshes.

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

[0023] S1, in a first polar solvent, diketene and an alcohol amine compound react at -5-0°C to prepare an acetoacetyl alcohol amine compound;

[0024] S2, in a second polar solvent, heating the acetoacetolamine compound prepared in step S1 and cyanuric chloride to react to prepare a cyanuric chloride acetoacetamide compound;

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

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

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

[0028] Wherein, 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 alcoholamine 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. The present invention provides an acetoacetamide-modified polyvinyl alcohol (AAM-PVA), which uses s-triazine as a bridging group so that each equivalent of PVA can connect two molecules of acetoacetamide groups, while retaining the acetoacetyl active group and improving the hydrolysis resistance more than the acetoacetyl group.

[0031] 2. The acetoacetamide-modified polyvinyl alcohol (AAM-PVA) having a structure of formula I provided by the present invention has better water resistance than ordinary acetoacetylated polyethylene (AA-PVA). When the AAM-PVA of the present invention is used as a protective colloid in polyvinyl acetate (PVAc) emulsion polymerization, it is easier to undergo a grafting reaction with a cross-linking agent, thereby increasing the grafting rate of AA-PVA, thereby improving the water resistance of the PVAc emulsion adhesive and enhancing the tensile strength and stability of the adhesive.

[0032] 3. The AAM-PVA having the structure of Formula I provided by the present invention has simple synthesis steps and high reaction yield; at the same time, its structure is novel and has not been reported before. It is of great significance to broaden the types of PVAc emulsion polymerization protective colloids and their subsequent industrial applications in adhesives. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is N-(hydroxyethyl)acetoacetamide in Example 1 of the present invention 1 H NMR spectra;

[0034] Figure 2 is 3,5-bis[acetoacetylaminoethoxy]-chloro-s-triazine in Example 1 of the present invention 1 H NMR spectra;

[0035] Figure 3 The 3,5-bis[acetoacetylaminoethoxy]-triazine modified PVA (AA et -M-PVA 1 H NMR spectra;

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

[0037] Figure 5 AA in Example 1 of the present invention et TG spectrum of M-PVA. DETAILED DESCRIPTION

[0038] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0039] The present invention provides a hydrolysis-resistant acetoacetamide-modified polyvinyl alcohol having a structure as shown in Formula I:

[0040]

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

[0042] Both x and y are integers, x is 200-2500, y is 20-400; 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 alcohol amine compounds.

[0044] Preferably, the tertiary amine compound is one of trimethylamine, N,N-diisopropylethylamine (DIEA), triethylamine and dicyclohexylmethylamine. The alcoholamine compound is one of ethanolamine and n-propanolamine. The raw material for 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] The present invention also provides a method for preparing hydrolysis-resistant acetoacetamide-modified polyvinyl alcohol, comprising the following steps:

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

[0047] Diketene and an alcohol amine compound are reacted in a first polar solvent at a controlled temperature of 0°C. After standing, the solvent is removed by rotary evaporation, reduced pressure distillation and vacuum drying to finally generate the first step product: N-(hydroxyalkyl)acetoacetamide, the structure of which is shown in Formula II.

[0048]

[0049] The reaction equation is as follows:

[0050]

[0051] Here, R is a straight-chain alkyl group having 2 to 3 carbon atoms.

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

[0053] The first polar solvent includes but is not limited to acetone, tetrahydrofuran, acetonitrile, preferably acetonitrile.

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

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

[0056] The molar ratio of diketene to alcoholamine 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 acetoacetyl alcohol amine compound prepared in step S1 is heated to react with cyanuric chloride to prepare a cyanuric chloride acetoacetamide compound; in this step, the heating reaction temperature is 65°C; the second polar solvent is one of acetone, tetrahydrofuran and acetonitrile. The detailed steps of step S2 are as follows:

[0059] The N-(hydroxyalkyl) acetoacetamide shown in formula II prepared in step S1 and cyanuric chloride are subjected to heating reaction in a second polar solvent, and the solvent is removed by rotary evaporation, reduced pressure distillation and vacuum drying to finally generate the second step product: 3,5-bis[acetoacetamidoalkoxy]monochloro-s-triazine, the structure of which is shown in formula III.

[0060]

[0061] The reaction equation is as follows:

[0062]

[0063] Here, R is a straight-chain alkyl group having 2 to 3 carbon atoms.

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

[0065] The second polar solvent includes but is not limited to acetone, tetrahydrofuran, acetonitrile, preferably acetonitrile.

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

[0067] The reaction time is 3h.

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

[0069] S3, the cyanuric chloride acetoacetamide compound prepared in step S2 reacts with a tertiary amine compound and polyvinyl alcohol in a third polar solvent to generate hydrolysis-resistant acetoacetamide-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[acetoacetamidoalkoxy]-chloro-s-triazine shown in formula III prepared in step S2, a tertiary amine compound and PVA are subjected to heating reaction in a third polar solvent under alkaline conditions, and then washed with alcohol, rotary evaporated, reduced pressure distilled and vacuum dried to remove the solvent, and finally a PVA (AAM-PVA) product modified with a bisacetoacetamide group is generated, as shown in formula I.

[0071]

[0072] The reaction equation is as follows:

[0073]

[0074] Here, R is a straight-chain alkyl group having 2 to 3 carbon atoms.

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

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

[0077] The molar ratio of 3,5-bis[acetoacetamidoalkoxy]monochloro-s-triazine represented by formula III to the tertiary amine compound is 1:1.

[0078] The molar ratio of 3,5-bis[acetoacetamidoalkoxy]monochloro-s-triazine represented by formula III to the base is 1:1.

[0079] The mass ratio of 3,5-bis[acetoacetamidoalkoxy]monochloro-s-triazine represented by formula III to PVA is 1:1-4:1, preferably 2:1.

[0080] The catalyst includes but is not limited to trimethylamine, N, N-diisopropylethylamine (DIEA), triethylamine, dicyclohexylmethylamine and other tertiary amines commonly used to prepare quaternary ammonium salts, preferably N, N-diisopropylethylamine.

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

[0082] The organic solvent includes but is not limited to acetone, acetonitrile, DMF, preferably acetonitrile.

[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°C, preferably 85°C.

[0085] The reaction time is 3h.

[0086] In the washing process of the product, anhydrous methanol is used as the washing solvent; the equipment used is a container with heating and stirring, and various mixers, reactors and other equipment can be used.

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

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

[0089] Example 1

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

[0091] Add diketene (1.86g, 0.022mol, 0.05eq) and acetonitrile (35.24mL) to a 500mL four-necked flask and stir thoroughly while controlling the temperature in the flask between -5-0℃. Then add diketene (35.2g, 0.418mol, 0.95eq) and ethanolamine (31.44g, 0.51mol, 1.2eq) to two separating funnels respectively, add diketene at a rate of 220g / h, and add ethanolamine at a rate of 196.5g / h, for a total of four hours. The entire dropwise reaction is placed in a low-temperature constant temperature circulation tank to keep the temperature in the flask at -5-0℃. After the reaction is completed, warm up to room temperature, stand for 12h, vacuum evaporation the reaction solution to remove the solvent acetonitrile, and then put it into a vacuum drying oven for drying. N-(hydroxyethyl)acetoacetamide is obtained, numbered 1-1a, with a structure as shown in formula IV, and a yield of 90%. 1 H NMR (400 MHz, CDCl 3 )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[acetoacetylaminoethoxy]-chloro-s-triazine

[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)acetoacetamide (11.61 g, 0.08 mol, 2 eq) and Na 2 CO 3 (8.4 g, 0.08 mol, 2 eq) was also added to a 500 mL four-necked flask, and the mixture was stirred and heated to 65 ° C for 3 h. After the reaction was completed, the solid and liquid were separated by suction filtration, and the reaction liquid was vacuum evaporated to remove the solvent acetonitrile, and then placed in a vacuum drying oven for drying. 3,5-bis[acetoacetylaminoethoxy]-chloro-s-triazine was obtained, numbered 1-2b, with a structure as shown in Formula V, and a yield of 85%. 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] PVA (11.32 g, 0.5 eq) of 200 mesh 9905 (99% alcoholysis degree, 500 degree of polymerization), acetonitrile (70 mL), 3,5-bis[acetoacetamidoethoxy]-chloro-s-triazine (25.81 g, 0.1 mol, 1 eq) prepared in Example 1 (1-b), DIEA (12.93 g, 0.1 mol, 1 eq), and NaOH (4 g, 0.1 mol, 1 eq) were added to a 250 mL four-necked flask, stirred thoroughly, and heated to 85°C for 3 hours. After the reaction was completed, the solid and liquid were separated by suction filtration, the reaction solution was vacuum evaporated to remove the solvent acetonitrile, and then placed in a vacuum drying oven for drying. AA was obtained. et M-PVA, numbered 1-3c, has a structure as shown in Formula VI, a yield of 97%, and a grafting rate of 10%.

[0098]

[0099] in, Figure 1 is N-(hydroxyethyl)acetoacetamide in Example 1 of the present invention 1 H NMR spectra; Figure 2is 3,5-bis[acetoacetylaminoethoxy]-chloro-s-triazine in Example 1 of the present invention 1 H NMR spectra; Figure 3 The 3,5-bis[acetoacetylaminoethoxy]-triazine modified PVA (AA et M-PVA 1 H NMR spectra; Figure 4 AA in Example 1 of the present invention et IR spectrum of M-PVA; Figure 5 AA in Example 1 of the present invention et TG spectrum of M-PVA.

[0100] Example 2

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

[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 and stirred thoroughly while the temperature in the flask was controlled between -5 and 0 ° C. Subsequently, diketene (35.2 g, 0.418 mol, 0.95 eq) and ethanolamine (26.2 g, 0.425 mol, 1 eq) were added to two separating funnels, diketene was added dropwise at a rate of 220 g / h, and ethanolamine was added dropwise at a rate of 196.5 g / h for a total of four hours. The entire dropwise reaction was placed in a low-temperature constant temperature circulation tank to keep the temperature in the flask at -5 to 0 ° C. After the reaction was completed, 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 placed in a vacuum drying oven for drying. N-(hydroxyethyl)acetoacetamide was obtained, numbered 2-1a, with a yield of 85%.

[0103] (2-b) Preparation of 3,5-bis[acetoacetylaminoethoxy]-chloro-s-triazine

[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)acetoacetamide (11.61 g, 0.08 mol, 2 eq) and Na 2 CO 3(8.4g, 0.08mol, 2eq) was also added to a 500mL four-necked flask, and stirred and heated to 50°C for 3h. After the reaction was completed, the solid and liquid were separated by suction filtration, and the reaction liquid was vacuum evaporated to remove the solvent acetonitrile, and then placed in a vacuum drying oven for drying. 3,5-bis[acetoacetylaminoethoxy]-chloro-s-triazine was obtained, numbered 2-2b, with a yield of 83%.

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

[0106] PVA (25.81 g, 1 eq) of 200 mesh 9905 (99% alcoholysis degree, 500 degree of polymerization), acetone (50 mL), 3,5-bis[acetoacetamidoethoxy]-chloro-s-triazine (25.81 g, 0.1 mol, 1 eq) obtained in Example 2 (2-b), DIEA (12.93 g, 0.1 mol, 1 eq), and KOH (5.6 g, 0.1 mol, 1 eq) were added to a 250 mL four-necked flask, stirred thoroughly, and heated to 75°C for 3 hours. After the reaction was completed, the solid and liquid were separated by suction filtration, the reaction solution was vacuum evaporated to remove the solvent acetone, and then placed in a vacuum drying oven for drying. AA was obtained. et M-PVA, numbered 2-3c, had a yield of 93% and a grafting rate of 7.3%.

[0107] Example 3

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

[0109] Add diketene (1.86g, 0.022mol, 0.05eq) and acetonitrile (37.59mL) to a 500mL four-necked flask and stir thoroughly while controlling the temperature in the flask between -5-0℃. Then add diketene (35.2g, 0.418mol, 0.95eq) and ethanolamine (36.68g, 0.595mol, 1.4eq) to two separating funnels respectively, drip diketene at a rate of 220g / h, and drip ethanolamine at a rate of 196.5g / h, for a total of four hours. The entire dropwise reaction is placed in a low-temperature constant temperature circulation tank, and the temperature in the flask is always kept at -5-0℃. After the reaction is completed, the temperature is raised to room temperature, and after standing for 18h, the reaction solution is vacuum-rotated to remove the solvent acetonitrile, and then placed in a vacuum drying oven for drying. N-(hydroxyethyl)acetoacetamide is obtained, numbered 3-1a, with a yield of 87%.

[0110] (3-b) Preparation of 3,5-bis[acetoacetylaminoethoxy]-chloro-s-triazine

[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)acetoacetamide (11.61 g, 0.08 mol, 2 eq) and Na 2 CO 3 (8.4g, 0.08mol, 2eq) was also added to a 500mL four-necked flask, and stirred and heated to 70°C for 3h. After the reaction was completed, the solid and liquid were separated by suction filtration, and the reaction liquid was vacuum evaporated to remove the solvent acetonitrile, and then placed in a vacuum drying oven for drying. 3,5-bis[acetoacetylaminoethoxy]-chloro-s-triazine was obtained, numbered 3-2b, with a yield of 83%.

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

[0113] A 250 mL four-necked flask was charged with 200 mesh 9905 (alcoholysis degree of 99%, polymerization degree of 500) PVA (5.2 g, 0.25 eq), DMF (65 mL), 3,5-bis[acetoacetamidoethoxy]-chloro-s-triazine (25.81 g, 0.1 mol, 1 eq) obtained in Example 3 (3-b), DIEA (12.93 g, 0.1 mol, 1 eq), NA 2 CO 3 (10.5g, 0.1mol, 1eq) was stirred thoroughly and heated to 90°C for 3h. After the reaction, the solid and liquid were separated by suction filtration, the reaction liquid was vacuum evaporated to remove the solvent DMF, and then placed in a vacuum drying oven to dry. AA was obtained et M-PVA, numbered 3-3c, had a yield of 90% and a grafting rate of 6.9%.

[0114] Example 4

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

[0116] Add diketene (1.86g, 0.022mol, 0.05eq) and acetone (38.33mL) to a 500mL four-necked flask and stir thoroughly while controlling the temperature in the flask between -10 and -5°C. Then add diketene (35.2g, 0.418mol, 0.95eq) and ethanolamine (31.44g, 0.51mol, 1.2eq) to two separating funnels respectively, drip diketene at a rate of 220g / h, and drip ethanolamine at a rate of 196.5g / h, for a total of four hours. The entire dropwise reaction is placed in a low-temperature constant temperature circulation tank, and the temperature in the flask is always kept at -10 to -5°C. After the reaction is completed, warm up to room temperature, stand for 12h, and then vacuum evaporate the reaction solution to remove the solvent acetone, and then put it into a vacuum drying oven for drying. N-(Hydroxyethyl)acetoacetamide was obtained, No. 4-1a, with a yield of 84%.

[0117] (4-b) Preparation of 3,5-bis[acetoacetylaminoethoxy]-chloro-s-triazine

[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)acetoacetamide (11.61 g, 0.08 mol, 2 eq) and Na 2 CO 3 (8.4 g, 0.08 mol, 2 eq) was also added to a 500 mL four-necked flask, and stirred and heated to 65°C for 3 h. After the reaction was completed, the solid and liquid were separated by suction filtration, the reaction liquid was vacuum evaporated to remove the solvent acetone, and then placed in a vacuum drying oven to dry, to obtain 3,5-bis[acetoacetamidoethoxy]-chloro-s-triazine, numbered 4-2b, with a yield of 84%.

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

[0120] A 250 mL four-necked flask was charged with 120 mesh 8503 (with alcoholysis degree of 85% and polymerization degree of 300) PVA (11.32 g, 0.5 eq), acetonitrile (70 mL), 3,5-bis[acetoacetamidoethoxy]-chloro-s-triazine (25.81 g, 0.1 mol, 1 eq) obtained in Example 4 (4-b), trimethylamine (5.91 g, 0.1 mol, 1 eq), NaOH (2 g, 0.05 mol, 0.5 eq) and NA 2 CO 3(5.25 g, 0.05 mol, 0.5 eq) was stirred thoroughly and heated to 85°C for 3 h. After the reaction was completed, the solid and liquid were separated by suction filtration, the reaction liquid was vacuum evaporated to remove the solvent acetonitrile, and then placed in a vacuum drying oven to dry. AA was obtained et M-PVA, numbered 4-3c, had a yield of 80% and a grafting rate of 4.3%.

[0121] Example 5

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

[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 and stirred thoroughly while the temperature in the flask was controlled between -5 and 0 ° C. Subsequently, diketene (35.2 g, 0.418 mol, 0.95 eq) and ethanolamine (31.44 g, 0.51 mol, 1.2 eq) were added to two separating funnels, diketene was added dropwise at a rate of 220 g / h, and ethanolamine was added dropwise at a rate of 196.5 g / h for a total of four hours. The entire dropwise reaction was placed in a low-temperature constant temperature circulation tank to keep the temperature in the flask at -5-0 ° C. After the reaction was completed, 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 acetone, and then placed in a vacuum drying oven for drying. N-(hydroxyethyl)acetoacetamide was obtained, numbered 5-1a, with a yield of 89%.

[0124] (5-b) Preparation of 3,5-bis[acetoacetylaminoethoxy]-chloro-s-triazine

[0125] 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 tetrahydrofuran and the solution became clear and transparent. Then, N-(hydroxyethyl)acetoacetamide (11.61 g, 0.08 mol, 2 eq) and Na 2 CO 3 (8.4g, 0.08mol, 2eq) was also added to a 500mL four-necked flask, and stirred and heated to 50°C for 3h. After the reaction was completed, the solid and liquid were separated by suction filtration, and the reaction liquid was vacuum evaporated to remove the solvent acetone, and then placed in a vacuum drying oven for drying. 3,5-bis[acetoacetamidoethoxy]-chloro-s-triazine was obtained, numbered 5-2b, with a yield of 81%.

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

[0127] A 250 mL four-necked flask was charged with 300 mesh 9510 (alcoholysis degree of 95%, polymerization degree of 1000) PVA (11.32 g, 0.5 eq), acetonitrile (70 mL), 3,5-bis[acetoacetamidoethoxy]-chloro-s-triazine (25.81 g, 0.1 mol, 1 eq) obtained in Example 5 (5-b), DIEA (12.93 g, 0.1 mol, 1 eq), KOH (2.8 g, 0.05 mol, 0.5 eq) and NA 2 CO 3 (5.25 g, 0.05 mol, 0.5 eq) was stirred thoroughly and heated to 85°C for 3 h. After the reaction was completed, the solid and liquid were separated by suction filtration, the reaction liquid was vacuum evaporated to remove the solvent acetonitrile, and then placed in a vacuum drying oven to dry. AA was obtained et M-PVA, numbered 5-3c, had a yield of 89% and a grafting rate of 7.7%.

[0128] Example 6

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

[0130] Add diketene (1.86g, 0.022mol, 0.05eq) and acetone (40.89mL) to a 500mL four-necked flask and stir thoroughly while controlling the temperature in the flask between -15 and -10°C. Then add diketene (35.2g, 0.418mol, 0.95eq) and ethanolamine (31.44g, 0.51mol, 1.2eq) to two separating funnels, drip diketene at a rate of 220g / h, and drip ethanolamine at a rate of 196.5g / h, for a total of four hours. The entire dropwise reaction is placed in a low-temperature constant temperature circulation tank, and the temperature in the flask is always kept at -15 to -10°C. After the reaction is completed, the temperature is raised to room temperature, and after standing for 6 hours, the reaction solution is vacuum-rotated to remove the solvent acetone, and then placed in a vacuum drying oven for drying. N-(Hydroxyethyl)acetoacetamide was obtained, No. 6-1a, with a yield of 83%.

[0131] (6-b) Preparation of 3,5-bis[acetoacetylaminoethoxy]-chloro-s-triazine

[0132] 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 tetrahydrofuran and the solution became clear and transparent. Then, N-(hydroxyethyl)acetoacetamide (11.61 g, 0.08 mol, 2 eq) and Na 2 CO 3(8.4 g, 0.08 mol, 2 eq) was also added to a 500 mL four-necked flask, and stirred and heated to 70°C for 3 h. After the reaction was completed, the solid and liquid were separated by suction filtration, the reaction liquid was vacuum evaporated to remove the solvent acetone, and then placed in a vacuum drying oven for drying. 3,5-bis[acetoacetylaminoethoxy]-chloro-s-triazine was obtained, numbered 6-2b, with a yield of 83%.

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

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

[0135] Example 7

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

[0137] Add diketene (1.86 g, 0.022 mol, 0.05 eq) and tetrahydrofuran (47.59 mL) to a 500 mL four-necked flask and stir thoroughly while controlling the temperature in the flask between -5 and 0 °C. Then add diketene (35.2 g, 0.418 mol, 0.95 eq) and ethanolamine (31.44 g, 0.51 mol, 1.2 eq) to two separating funnels, drip diketene at a rate of 220 g / h, and drip ethanolamine at a rate of 196.5 g / h, for a total of four hours. The entire dropwise reaction is placed in a low-temperature constant temperature circulation tank to keep the temperature in the flask at -5-0 °C. After the reaction is completed, warm up to room temperature, stand for 12 hours, and then vacuum evaporate the reaction solution to remove the solvent tetrahydrofuran, and then put it into a vacuum drying oven to dry to obtain N-(hydroxyethyl) acetoacetamide, numbered 7-1a, with a yield of 85%.

[0138] (7-b) Preparation of 3,5-bis[acetoacetylaminoethoxy]-chloro-s-triazine

[0139] Cyanuric 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 cyanuric chloride was completely dissolved in the tetrahydrofuran and the solution became clear and transparent. Then, N-(hydroxyethyl)acetoacetamide (11.61 g, 0.08 mol, 2 eq) and Na 2 CO 3 (8.4 g, 0.08 mol, 2 eq) was also added to a 500 mL four-necked flask, and stirred and heated to 65 ° C for 3 h. After the reaction was completed, the solid and liquid were separated by suction filtration, and the reaction liquid was vacuum evaporated to remove the solvent tetrahydrofuran, and then placed in a vacuum drying oven to dry to obtain 3,5-bis[acetoacetylaminoethoxy]-chloro-s-triazine, numbered 7-2b, with a yield of 84%.

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

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

[0142] Example 8

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

[0144] Add diketene (1.86g, 0.022mol, 0.05eq) and tetrahydrofuran (44.42mL) to a 500mL four-necked flask and stir thoroughly while controlling the temperature in the flask between -5-0℃. Then add diketene (35.2g, 0.418mol, 0.95eq) and ethanolamine (31.44g, 0.51mol, 1.2eq) to two separating funnels respectively, add diketene at a rate of 220g / h, and add ethanolamine at a rate of 196.5g / h, for a total of four hours. The entire dropwise reaction is placed in a low-temperature constant temperature circulation tank to keep the temperature in the flask at -5-0℃. After the reaction is completed, warm up to room temperature, stand for 12h, and then vacuum evaporate the reaction solution to remove the solvent tetrahydrofuran, and then put it into a vacuum drying oven to dry, to obtain N-(hydroxyethyl) acetoacetamide, numbered 8-1a, with a yield of 84%.

[0145] (8-b) Preparation of 3,5-bis[acetoacetylaminoethoxy]-chloro-s-triazine

[0146] Cyanuric 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 cyanuric chloride was completely dissolved in the tetrahydrofuran and the solution became clear and transparent. Then, N-(hydroxyethyl)acetoacetamide (11.61 g, 0.08 mol, 2 eq) and Na 2 CO 3 (8.4g, 0.08mol, 2eq) was also added to a 500mL four-necked flask, and stirred and heated to 50°C for 3h. After the reaction was completed, the solid and liquid were separated by suction filtration, and the reaction liquid was vacuum evaporated to remove the solvent tetrahydrofuran, and then placed in a vacuum drying oven to dry to obtain 3,5-bis[acetoacetylaminoethoxy]-chloro-s-triazine, numbered 8-2b, with a yield of 82%.

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

[0148] PVA (11.32 g, 0.5 eq) of 200 mesh 9820 (98% alcoholysis degree, 2000 degree of polymerization), acetonitrile (70 mL), 3,5-bis[acetoacetamidoethoxy]-chloro-s-triazine (25.81 g, 0.1 mol, 1 eq) obtained in Example 8 (8-b), DIEA (12.93 g, 0.1 mol, 1 eq), and NaOH (4 g, 0.1 mol, 1 eq) were added to a 250 mL four-necked flask, stirred thoroughly, and heated to 85° C. for 3 h. After the reaction was completed, the solid and liquid were separated by suction filtration, the reaction solution was subjected to vacuum rotary evaporation to remove the solvent acetonitrile, and then placed in a vacuum drying oven for drying to obtain AA. etM-PVA, numbered 8-3c, had a yield of 89% and a grafting rate of 8.4%.

[0149] Example 9

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

[0151] Add diketene (1.86g, 0.022mol, 0.05eq) and tetrahydrofuran (50.77mL) to a 500mL four-necked flask and stir thoroughly while controlling the temperature in the flask between -5-0℃. Then add diketene (35.2g, 0.418mol, 0.95eq) and ethanolamine (31.44g, 0.51mol, 1.2eq) to two separating funnels respectively, add diketene at a rate of 220g / h, and add ethanolamine at a rate of 196.5g / h, for a total of four hours. The entire dropwise reaction is placed in a low-temperature constant temperature circulation tank to keep the temperature in the flask at -5-0℃. After the reaction is completed, warm up to room temperature, stand for 12h, and then vacuum evaporate the reaction solution to remove the solvent tetrahydrofuran, and then put it into a vacuum drying oven to dry, to obtain N-(hydroxyethyl) acetoacetamide, numbered 9-1a, with a yield of 84%.

[0152] (9-b) Preparation of 3,5-bis[acetoacetylaminoethoxy]-chloro-s-triazine

[0153] Cyanuric 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 cyanuric chloride was completely dissolved in the tetrahydrofuran and the solution became clear and transparent. Then, N-(hydroxyethyl)acetoacetamide (11.61 g, 0.08 mol, 2 eq) and Na 2 CO 3 (8.4g, 0.08mol, 2eq) was also added to a 500mL four-necked flask, and stirred and heated to 70°C for 3h. After the reaction, the solid and liquid were separated by suction filtration, and the reaction liquid was vacuum evaporated to remove the solvent tetrahydrofuran, and then placed in a vacuum drying oven to dry to obtain 3,5-bis[acetoacetylaminoethoxy]-chloro-s-triazine, numbered 9-2b, with a yield of 83%.

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

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

[0156] Example 10

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

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

[0159]

[0160] (10-b) Preparation of 3,5-bis(acetoacetamidopropoxy)-chloro-s-triazine

[0161] The preparation process is the same as step (1-b) of Example 1, except that the amine compound is the product 10-1a obtained in Example 10 (10-a), to obtain 3,5-bis[acetoacetamidopropoxy]monochloro-isotriazine, numbered 10-2b, with a structure as formula (VIII) and a yield of 84%.

[0162]

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

[0164] The preparation process is the same as step (1-c) of Example 1 except that the amine compound is the product 10-2b obtained in Example 10 (10-b), and the other conditions and methods are the same as those in step (1-c) of Example 1 to obtain AA pr M-PVA, numbered 10-3c, has a structure as shown in Formula IX, a yield of 92%, and a grafting rate of 6.5%.

[0165]

[0166] Comparative Example 1

[0167] Select the PVA series products of China Sichuan Wei Chemical, model 9905 (alcoholysis degree 99%, polymerization degree 500, viscosity 5-6.5MPa.s, volatile content max 5%, ph = 5-7).

[0168] Comparative Example 2

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

[0170] Comparative Example 3

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

[0172] Performance Testing

[0173] Test 1: Performance test when used as a protective colloid in PVAc emulsion polymerization

[0174] The main relevant indicators of the PVAc emulsion prepared by using the products 1-3c, 10-3c and the products in comparative examples 1-3 are shown in Table 1. (There are no special requirements for the preparation of PVAc emulsion. You only need to select any one on the market, replace the protective colloid PVA or AA-PVA with the products in products 1-3c, 10-3c and comparative examples 1-3, and keep other conditions unchanged. Here is a commonly used laboratory preparation method as Example 1).

[0175] Example 1

[0176] 1. Dissolve polyvinyl alcohol

[0177] In a 250mL four-necked reaction flask equipped with an electric stirring device, a spherical condenser, a dropping funnel, a thermometer and a nitrogen conduit, 3g of 9905PVA (alcoholysis degree 99%, polymerization degree 500) in Comparative Example 1 and 50mL of deionized water were added, and stirring was started; the water bath temperature was gradually raised to 80°C and kept constant until the polyvinyl alcohol was completely dissolved.

[0178] 2. Prepare solution

[0179] Weigh 0.3 g of ammonium persulfate and dissolve it in 3 mL of water to make 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; replace the air with nitrogen and maintain the temperature at 60-65°C (reflux) for reaction.

[0183] (3) When the temperature rises to 80-83°C, the reflux gradually decreases. Start to slowly add 43 mL of vinyl acetate using a dropping funnel. Control the dropping speed to keep the reaction temperature between 80±2°C and moderate reflux. The addition should be completed within about 2 hours. During the addition of vinyl acetate, add 1.2 mL of initiator solution in 3-4 portions.

[0184] (4) After the monomers are added, the remaining initiator solution is added at once, and the reaction temperature is raised to 90-95°C and maintained for 0.5 h before stopping the reaction.

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

[0186] In Table 1: Water resistance of the emulsion According to the method of GB / T 23445-2009, the tensile strength and elongation at break of the emulsion were tested, where:

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

[0188] The film preparation method is as follows: weigh 5g of raw PVA (products 1-3c, 10-3c and the products in comparative example 1-3) and add 100mL of pure water, heat to above 90°C until completely dissolved, and prepare a 5% PVA aqueous solution. Then, on a 23x17cm 2 Pour the PVA aqueous solution onto a framed glass plate, use the casting method to make a film, and dry it at room temperature. Finally, cut it into strips of 50mm in length and 20mm in width and store it in a desiccator. (The film with a uniform thickness of 0.05mm was used for testing.)

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

[0190] Decrease rate of elongation at break = (elongation at break without treatment - elongation at break after water treatment) * 100% / elongation at break without treatment.

[0191] Table 1 Performance indicators of PVAc emulsion

[0192]

[0193] It can be seen from Table 1 that the tensile strength and elongation at break of the samples prepared by using the products 1-3c, 10-3c and the products in comparative examples 1-3 as protective colloids after water treatment all decreased to varying degrees. Among them, the tensile strength decrease rate of the emulsion using 1-3c as the protective colloid was 7%, and the elongation at break decreased by 9%; the tensile strength decrease rate of the emulsion using 10-3c as the protective colloid was 8%, and the elongation at break decreased by 11%, while the tensile strength decrease rate of the emulsion prepared by using PVA of Sichuan Wei or AA-PVA of Mitsubishi Chemical of Japan as the protective colloid was 9%-13%, and the elongation at break decreased by 11%-22%. It shows that using AAM-PVA as a protective colloid can significantly improve the water resistance of the emulsion.

[0194] Test 2: Water resistance test after film formation

[0195] Film preparation: Weigh 5g of raw PVA (products 1-3c, 10-3c and the products in comparative example 1-3) and add 100mL of pure water, heat to above 90°C until completely dissolved, and prepare a 5% PVA aqueous solution. Then, on a 23x17cm 2 Pour the PVA aqueous solution onto a framed glass plate, use the casting method to make a film, and dry it at room temperature. Finally, cut it into 50mm diameter discs and store them in a desiccator. (A film with a uniform thickness of 0.05mm was used for testing).

[0196] Three pieces of 50 mm diameter disc membranes were selected from products 1-3c, 10-3c and the products in comparative examples 1-3 (with a consistent thickness of 0.05 mm). The membranes were then immersed in pure water, 0.1 mol / L NaOH solution and 2% (volume fraction) acetic acid solution, respectively, and left to stand at room temperature for 24 hours. The water resistance is shown in Table 2 (√ for good performance, × for bad performance, and - for average performance).

[0197] Table 2 Water resistance of AAM-PVA film

[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] It can be seen from Table 2 that the products 1-3c, 10-3c and the products in Comparative Example 1-3 were made into films and tested in neutral, alkaline and acidic solutions. Products 1-3c and 10-3c had the best water resistance and their acid and alkali resistance was also significantly improved.

[0200] Compared with the prior art, the present invention has the following beneficial effects:

[0201] 1. The present invention provides a diacetoacetamide-modified polyvinyl alcohol (AAM-PVA), which uses s-triazine as a bridging group so that each equivalent of PVA can connect two molecules of acetoacetamide groups, while retaining the acetoacetyl active group and improving the hydrolysis resistance more than the acetoacetyl group.

[0202] 2. The acetoacetamide-modified polyvinyl alcohol (AAM-PVA) having a structure of formula I provided by the present invention has better water resistance than ordinary acetoacetylated polyethylene (AA-PVA). When the AAM-PVA of the present invention is used as a protective colloid in polyvinyl acetate (PVAc) emulsion polymerization, it is easier to undergo a grafting reaction with a cross-linking agent, thereby increasing the grafting rate of AA-PVA, thereby improving the water resistance of the PVAc emulsion adhesive and enhancing the tensile strength and stability of the adhesive.

[0203] 3. The AAM-PVA having the structure of Formula I provided by the present invention has simple synthesis steps and high reaction yield; at the same time, its structure is novel and has not been reported before. It is of great significance to broaden the types of PVAc emulsion polymerization protective colloids and their subsequent industrial applications in adhesives.

[0204] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

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

2. The hydrolysis-resistant acetoacetamide-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 alcohol amine compounds.

3. The hydrolysis-resistant acetoacetamide-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 acetoacetamide-modified polyvinyl alcohol according to claim 2, characterized in that: The alcoholamine compound is one of ethanolamine and n-propanolamine.

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

6. A method for preparing a hydrolysis-resistant acetoacetamide-modified polyvinyl alcohol as claimed in any one of claims 1 to 5, characterized in that: The steps include: S1, in a first polar solvent, diketene and an alcohol amine compound react at -5-0°C to prepare an acetoacetyl alcohol amine compound; S2, in a second polar solvent, heating the acetoacetolamine compound prepared in step S1 and cyanuric chloride to react to prepare a cyanuric chloride acetoacetamide compound; S3, the cyanuric chloride acetoacetamide compound prepared in step S2 reacts with a tertiary amine compound and polyvinyl alcohol in a third polar solvent to generate hydrolysis-resistant acetoacetamide-modified polyvinyl alcohol.

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

8. The method for preparing the hydrolysis-resistant acetoacetamide-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 the hydrolysis-resistant acetoacetamide-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 alcoholamine compound is one of ethanolamine and n-propanolamine.

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