阅读说明：本技术 一种不饱和吡啶鎓内盐在制备封闭型聚氨酯预聚物中的应用 (Application of unsaturated pyridinium inner salt in preparation of blocked polyurethane prepolymer ) 是由 张成燕 桑听听 黄毅 张田林 于 2021-01-14 设计创作，主要内容包括：本发明涉及一种不饱和吡啶鎓内盐在制备封闭型聚氨酯预聚物中的应用,所述不饱和吡啶鎓内盐指的是N-(3-甲酰基4-负氧基苄基)-4-乙烯吡啶鎓内盐。其用作端异氰酸酯基聚氨酯预聚体的可聚合封闭剂,目的是所述封闭型聚氨酯预聚体在受热解封闭时,释放出来的不饱和吡啶鎓内盐因受热也发生聚合反应转化为聚合物滞留在材料其中,充当填充物或材料的功能改性剂,实现物质资源的优化利用,不再造成环境污染或资源浪费。所述端异氰酸酯基聚氨酯预聚体是由端羟基聚合物与多异氰酸酯制成端异氰酸酯基聚氨酯预聚物。所述端羟基聚合物指的是端羟基聚乙二醇单烷基醚、单端羟基聚乙烯吡咯烷酮、或端羟基聚醚季铵盐中的一种或两种以上。(The invention relates to application of an unsaturated pyridinium inner salt in preparation of a blocked polyurethane prepolymer, wherein the unsaturated pyridinium inner salt is N- (3-formyl 4-negative oxygen radical benzyl) -4-vinyl pyridinium inner salt. The unsaturated pyridinium inner salt released during the deblocking of the blocked polyurethane prepolymer by heating is also subjected to polymerization reaction and converted into a polymer to be retained in the material, and the polymer is used as a functional modifier of a filler or a material, so that the optimized utilization of material resources is realized, and the environmental pollution or the resource waste is avoided. The isocyanate-terminated polyurethane prepolymer is prepared from a hydroxyl-terminated polymer and polyisocyanate. The hydroxyl-terminated polymer refers to one or more than two of hydroxyl-terminated polyethylene glycol monoalkyl ether, hydroxyl-terminated polyvinylpyrrolidone or hydroxyl-terminated polyether quaternary ammonium salt.)

1. The application of unsaturated pyridinium inner salt in preparing blocked polyurethane prepolymer is realized by the following steps: weighing polyisocyanate, a catalyst and an organic solvent in a reactor, weighing a hydroxyl-terminated polymer according to the proportion that the R value of polyurethane is 2.0-2.2, adding the hydroxyl-terminated polymer into the reactor, controlling the temperature to be 50-90 ℃, stirring and reacting for 2-12 hours, and preparing a solution of isocyanate-terminated polyurethane prepolymer after analyzing and detecting the content of-NCO in reaction materials in the reactor to be consistent with a preset value by adopting a di-n-butylamine titration analysis method; adding unsaturated pyridinium inner salt serving as a polymerizable blocking agent into the isocyanate-terminated polyurethane prepolymer solution, continuously keeping the temperature at 50-90 ℃ for reaction until no-NCO can be detected in the materials in the reactor, then distilling to recover the organic solvent, and then reducing the temperature of the materials in the reactor to room temperature to obtain the isocyanate-terminated polyurethane prepolymer with the unsaturated pyridinium inner salt at the closed end, wherein the unsaturated pyridinium inner salt is N- (3-formyl 4-negative oxygen benzyl) -4-vinyl pyridinium inner salt;

wherein the mass ratio of the polyisocyanate to the hydroxyl-terminated polymer to the catalyst to the unsaturated pyridinium inner salt to the organic solvent is 100/50-500/0.5-5/5-500/100-1000.

2. Use of an unsaturated pyridinium inner salt according to claim 1 for the preparation of a blocked polyurethane prepolymer, characterized in that the N- (3-formyl 4-N-oxybenzyl) -4-vinylpyridinium inner salt is prepared by: weighing 5-chloromethyl salicylaldehyde, 4-vinylpyridine and hydroquinone, dissolving in a solvent to respectively prepare a 5-chloromethyl salicylaldehyde solution and a 4-vinylpyridine mixed hydroquinone solution, controlling the temperature to be 0-100 ℃, adding the 5-chloromethyl salicylaldehyde solution into the 4-vinylpyridine mixed hydroquinone solution, and stirring for reaction for 2-20 hours to prepare N- (3-formyl 4-hydroxybenzyl) -4-vinylpyridinium chloride salts; then adding an alkali reagent, continuously stirring and reacting for 2-12 hours, and performing rotary evaporation to recover the solvent and the alkali reagent to obtain the N- (3-formyl 4-negative oxygen benzyl) -4-vinylpyridinium inner salt;

wherein the molar usage ratio of the 5-chloromethyl salicylaldehyde, the 4-vinylpyridine and the alkali reagent is 1: 1-1.05: 1-1.5; the dosage of the hydroquinone is 0.1-0.3% of the mass dosage of the 4-vinylpyridine.

3. Use of an unsaturated pyridinium inner salt according to claim 2 for the preparation of a blocked polyurethane prepolymer, characterized in that the base reagent is selected from one of triethylamine, tributylamine, 4-dimethylaminopyridine, N '-tetramethylethylenediamine, triethylenediamine, N' -dimethylpiperazine or N-methylmorpholine.

4. Use of an unsaturated pyridinium inner salt according to claim 2 for the preparation of blocked polyurethane prepolymers, the solvent is one or more than two of acetone, butanone, cyclohexanone, tetrahydrofuran, 1, 4-dioxane, chlorobenzene, chloroform, 1, 2-dichloroethane, toluene, xylene, decalin, methyl acetate, ethyl acetate, butyl acetate, N-methylpyrrolidone, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, N, N-dimethylformamide, N, N-dimethylacetamide, triethylamine, tributylamine, p-dimethylaminopyridine, N, N, N ', N ' -tetramethylethylenediamine, triethylenediamine, N, N ' -dimethylpiperazine, N-methylmorpholine or dimethyl sulfoxide;

wherein the dosage of the solvent is 0.5-5 times of the total mass of the 5-chloromethyl salicylaldehyde and the 4-vinylpyridine.

5. Use of an unsaturated pyridinium inner salt according to claim 1 for the preparation of blocked polyurethane prepolymers, the polyisocyanate is one of toluene diisocyanate, diphenylmethane diisocyanate, p-phenylene diisocyanate, tetramethylxylylene diisocyanate, 1, 5-naphthalene diisocyanate, 1, 4-cyclohexyl diisocyanate, 1, 4-butylene diisocyanate, 1, 6-hexamethylene diisocyanate, 1, 10-sunflower diisocyanate, 4' -dicyclohexylmethane diisocyanate, isophorone diisocyanate, trimethylhexane diisocyanate, toluene diisocyanate trimer, diphenylmethane diisocyanate trimer, 1, 6-hexamethylene diisocyanate trimer, isophorone diisocyanate trimer or hexamethylene diisocyanate trimer.

6. Use of an unsaturated pyridinium inner salt according to claim 1 for the preparation of blocked polyurethane prepolymers, the organic solvent is one or more of acetone, butanone, cyclohexanone, tetrahydrofuran, 1, 4-dioxane, chlorobenzene, chloroform, 1, 2-dichloroethane, toluene, xylene, decalin, methyl acetate, ethyl acetate, butyl acetate, N-methylpyrrolidone, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, N, N-dimethylformamide, N, N-dimethylacetamide, triethylamine, tributylamine, p-dimethylaminopyridine, N, N, N ', N ' -tetramethylethylenediamine, triethylenediamine, N, N ' -dimethylpiperazine, N-methylmorpholine or dimethyl sulfoxide.

7. The use of an unsaturated pyridinium inner salt in the preparation of a blocked polyurethane prepolymer according to claim 1, wherein the hydroxyl terminated polymer is one or more of hydroxyl terminated polyethylene glycol monoalkyl ether, hydroxyl terminated polyvinylpyrrolidone, or hydroxyl terminated polyether quaternary ammonium salt;

wherein the polyethylene glycol monoalkyl ether has a structure shown in a general formula (I):

wherein R in the general formula (I)₁Alkyl refers to C₁~C₁₈A hydrocarbon group, n is a natural number of 2 to 200;

the structure of the single-end hydroxyl polyvinylpyrrolidone is shown as a general formula (II):

wherein n in the general formula (II) refers to a natural number in a range of 2-200;

the hydroxyl-terminated polyether quaternary ammonium salt has a structure shown in a general formula (III):

wherein R in the general formula (III)₁、R₂And R₃Are respectively selected from substituted or unsubstituted C₁~C₁₈One of the hydrocarbon radicals, X^-Refers to Cl^-Or Br^-And n is a natural number in the range of 2-200.

8. The use of an unsaturated pyridinium inner salt according to claim 1 for the preparation of a blocked polyurethane prepolymer, characterized in that the catalyst refers to a complex of an organic amine and an organic tin;

wherein the organic amine refers to one of triethylamine, tributylamine, p-dimethylaminopyridine, N, N, N ', N ' -tetramethylethylenediamine, triethylenediamine, N, N ' -dimethylpiperazine or N-methylmorpholine;

the organic tin refers to one of dibutyltin dilaurate, stannous octoate, stannous oxalate, dibutyltin dimaleate, dibutyltin dilauryl sulfide or dibutyltin diacetate;

the mass ratio of the organic amine to the organic tin is 1: 0.5-5.

Technical Field

The invention relates to an application of unsaturated pyridinium inner salt in preparation of a blocked polyurethane prepolymer, in particular to a polymerizable blocking agent of an isocyanate-terminated polyurethane prepolymer using N- (3-formyl 4-negative oxybenzyl) -4-vinylpyridinium inner salt, belonging to the field of functional polymer materials.

Background

The polyurethane prepolymer is a product type of polyurethane materials and is prepared by reacting polyisocyanates and polyols in a non-equimolar ratio. It can further react with polyisocyanate, polyol, chain extender or material containing N-H/O-H active group to produce polyurethane material or composite material with certain performance, function and characteristic. The polyurethane prepolymer contains chemically active end groups in the structure, belongs to liquid products, is easy to process and form, and is widely applied to various production and living fields, including polyurethane casting elastomers, polyurethane adhesives, polyurethane coatings or dipping coatings and the like. According to the active end group in the polyurethane prepolymer, the polyurethane prepolymer can be mainly divided into: the polyurethane prepolymer comprises isocyanate-terminated polyurethane prepolymer, hydroxyl-terminated polyurethane prepolymer, closed polyurethane prepolymer, polyurethane prepolymer with terminal groups of terminal acrylate groups and terminal silane groups and the like, wherein the terminal groups are generated by the reaction of other raw materials. The isocyanate-terminated polyurethane prepolymer is one of the commonly used varieties, is mainly used as a curing agent of a polyurethane adhesive or a coating, and is a post-chemical modifier or a post-finishing agent of cotton fabric, silk, wood, phenolic resin, amino resin, polyamide, polyurethane and other materials. However, the isocyanate-terminated polyurethane prepolymer has short natural storage time and is easily affected by humid air in the use process, and people invent a chemically inert blocked polyurethane prepolymer under natural conditions.

The blocked polyurethane prepolymer is prepared by reacting a blocked isocyanate group of a blocked isocyanate polyurethane prepolymer with a blocking agent. The terminal isocyanate group of the closed polyurethane prepolymer loses chemical activity temporarily, and the closed polyurethane prepolymer has high stability under natural conditions and is easy to store, transport or use. In the application process of the closed polyurethane prepolymer, the closing agent is lost through thermal decomposition, and then the isocyanate-based polyurethane prepolymer is reproduced. Commonly used blocking agents include organic alcohols, thiols, arylamine amides, phenols, ethyl acetoacetate, imidazole, acetoxime, sodium bisulfite, boric acid, and the like. The molecular structures of the sealing agents contain active N-H, C-H, O-H or S-H groups, and the sealing agents can perform addition reaction with isocyanate groups of the isocyanate group-terminated polyurethane prepolymer to prepare polyurethane prepolymer containing urethane structural units, namely the sealing polyurethane prepolymer. However, in the application process of the blocked polyurethane prepolymer, the blocking agent can be released, so that harm or pollution is caused to the health of workers in the production process and on site and the atmospheric environment, and meanwhile, no-end waste of material resources is caused. In recent years, attention has been paid to the development of novel blocking agents having low toxicity, high efficiency and low deblocking temperature. However, there is still no consideration of the secondary use of the blocking agent released upon deblocking.

The deblocking process of the blocked polyurethane prepolymer is usually carried out by heating. When the deblocking temperature is reached, the blocked polyurethane prepolymer begins to thermally decompose, and the blocked isocyanate-based polyurethane prepolymer is reproduced while the blocking agent is released. The prior art teaches that deblocking temperatures are typically between 50 and 170 ℃. The deblocking temperature is also a suitable condition for polymerization reaction of some olefin monomers, therefore, the invention designs an unsaturated pyridinium inner salt which is used as a polymerizable blocking agent of the isocyanate-terminated polyurethane prepolymer, aiming at realizing that when the unsaturated pyridinium inner salt is deblocked by heating, the released unsaturated pyridinium inner salt also generates polymerization reaction due to heating and is retained in a material, and the unsaturated pyridinium inner salt serves as a functional modifier of a filler or the material, thereby realizing the optimized utilization of material resources and avoiding releasing the unsaturated pyridinium inner salt into the atmosphere to cause environmental pollution or resource waste.

Disclosure of Invention

The invention provides an unsaturated pyridinium inner salt used as a polymerizable sealing agent of an isocyanate-terminated polyurethane prepolymer, and aims to provide a functional modifier of a filler or a material, wherein the released unsaturated pyridinium inner salt is subjected to polymerization reaction due to heating and is converted into a polymer to be retained in the specific material when the sealed polyurethane prepolymer is deblocked by heating, so that the optimized utilization of material resources is realized, and the environment pollution or the resource waste caused by releasing the unsaturated pyridinium inner salt in the air is avoided. The purpose of the invention is realized by the following steps:

weighing polyisocyanate and an organic solvent in a reactor, controlling the temperature to be 50-90 ℃, then weighing hydroxyl-terminated polymer and a catalyst according to the molar ratio of isocyanate (-NCO) to hydroxyl (-OH) (namely a polyurethane R value) being 2.0-2.2, slowly adding the hydroxyl-terminated polymer and the catalyst into the reactor, stirring and reacting for 2-12 hours, and preparing a solution of isocyanate-terminated polyurethane prepolymer after analyzing and detecting that the-NCO content in reaction materials in the reactor accords with a preset value by adopting a di-n-butylamine titration analysis method; and then, adding unsaturated pyridinium inner salt serving as a polymerizable blocking agent into the isocyanate-terminated polyurethane prepolymer solution, continuously keeping the temperature at 50-90 ℃ for reaction until-NCO cannot be detected in the materials in the reactor, distilling to recover volatile substances (comprising an organic solvent, a catalyst and an alkali reagent), and then reducing the temperature of the materials in the reactor to room temperature to obtain the isocyanate-terminated polyurethane prepolymer with the unsaturated pyridinium inner salt at the closed end, wherein the unsaturated pyridinium inner salt is N- (3-formyl 4-negative oxygen benzyl) -4-vinyl pyridinium inner salt.

The polyisocyanate refers to one of toluene diisocyanate, diphenylmethane diisocyanate, p-phenylene diisocyanate, tetramethylxylylene diisocyanate, 1, 5-naphthalene diisocyanate, 1, 4-cyclohexyl diisocyanate, 1, 4-butylene diisocyanate, 1, 6-hexamethylene diisocyanate, 1, 10-sunflower diisocyanate, 4' -dicyclohexylmethane diisocyanate, isophorone diisocyanate, trimethylhexane diisocyanate, toluene diisocyanate trimer, diphenylmethane diisocyanate trimer, 1, 6-hexamethylene diisocyanate trimer, isophorone diisocyanate trimer or hexamethylene diisocyanate trimer.

The organic solvent is one or more of acetone, butanone, cyclohexanone, tetrahydrofuran, 1, 4-dioxane, chlorobenzene, chloroform, 1, 2-dichloroethane, toluene, xylene, decalin, methyl acetate, ethyl acetate, butyl acetate, N-methylpyrrolidone, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, N, N-dimethylformamide, N, N-dimethylacetamide, triethylamine, tributylamine, p-dimethylaminopyridine, N, N, N ', N ' -tetramethylethylenediamine, triethylenediamine, N, N ' -dimethylpiperazine, N-methylmorpholine or dimethyl sulfoxide.

The hydroxyl-terminated polymer refers to one or more than two of hydroxyl-terminated polyethylene glycol monoalkyl ether, single-ended hydroxyl polyvinylpyrrolidone or hydroxyl-terminated polyether quaternary ammonium salt;

wherein the hydroxyl-terminated polyethylene glycol monoalkyl ether has a structure shown in a general formula (I):

wherein R in the general formula (I)₁Alkyl refers to C₁~C₁₈A hydrocarbon group, n is a natural number of 2 to 200.

The single-end hydroxyl polyvinylpyrrolidone has a structure shown in a general formula (II):

wherein n in the general formula (II) refers to a natural number of 2-200.

The hydroxyl-terminated polyether quaternary ammonium salt has a structure shown in a general formula (III):

wherein R in the general formula (III)₁、R₂And R₃Are respectively selected from substituted or unsubstituted C₁~C₁₈One of the hydrocarbon radicals, X^-Refers to Cl^-Or Br^-And n is a natural number in the range of 2-200.

The catalyst refers to a compound of organic amine and organic tin, and the mass ratio of the organic amine to the organic tin is 1: 0.5-5;

wherein the organic amine refers to one of triethylamine, tributylamine, 4-dimethylamino pyridine, N, N, N ', N ' -tetramethyl ethylenediamine, triethylene diamine, N, N ' -dimethyl piperazine or N-methyl morpholine;

the organic tin refers to one of dibutyltin dilaurate, stannous octoate, stannous oxalate, dibutyltin dimaleate, dibutyltin didodecyl sulfide or dibutyltin diacetate.

The mass ratio of the polyisocyanate to the hydroxyl-terminated polymer to the catalyst to the sealant to the organic solvent is 100/50-500/0.5-5/5-500/100-1000.

It is well known to those skilled in the art that the hydroxyl group at the end of the macromolecule chain of the hydroxyl-terminated polyethylene glycol monoalkyl ether can be subjected to addition reaction with the polyisocyanate to obtain an isocyanate-terminated polyether polyurethane prepolymer. The terminal alkoxy polyether chain has amphiphilic property and relatively high freedom degree and free volume. And the terminal hydroxyl of the terminal hydroxyl polyvinylpyrrolidone can perform addition reaction with the polyisocyanate to prepare the isocyanate-terminated polyurethane prepolymer. The polyvinylpyrrolidone chain has the advantages of amphipathy, hygroscopicity, low toxicity, good physiological intermiscibility, relatively high degree of freedom and free volume, and can combine with water molecules to generate a hydrogel protection effect. The terminal hydroxyl of the terminal hydroxyl polyether quaternary ammonium salt can be subjected to addition reaction with the polyisocyanate to prepare the isocyanate-terminated polyurethane prepolymer. The quaternary ammonium cation and the polyether chain have the functional characteristics of disinfection, antibiosis, sterilization, hydrophilicity, water absorption, moisture retention and the like. The following reaction formulas (i) - (iii) specifically show the preparation process of the isocyanate-terminated polyurethane prepolymer by using diphenylmethane diisocyanate as one example of the polyisocyanate:

wherein R in the reaction formulae (I) - (III)₁、R₂Or R₃Respectively select C₁~C₁₈N is selected from one of natural numbers of 2-200, X^-Selected from Cl^-Or Br^-。

As can be seen from the reaction formulas I-III, the isocyanate-terminated polyurethane prepolymer disclosed by the invention is an isocyanate-terminated polyurethane prepolymer with a special function, and can be directly used for post-chemical modification of an organic material containing an N-H or O-H active group in a molecular structure. However, these isocyanate-terminated polyurethane prepolymers are not suitable for long-term storage, so that the present invention uses unsaturated pyridinium inner salt to perform a sealing treatment on the isocyanate-terminated polyurethane prepolymer to obtain an unsaturated pyridinium inner salt closed-end isocyanate-terminated polyurethane prepolymer, and the following reaction formulas (iv) - (sixth) specifically show the process of the unsaturated pyridinium inner salt closed-end isocyanate-terminated polyurethane prepolymer:

wherein R in reaction formulas (R) - (c)₁、R₂Or R₃Respectively select C₁~C₁₈N is selected from one of natural numbers of 2-200, X^-Selected from Cl^-Or Br^-。

The invention provides an application of an unsaturated pyridinium inner salt in preparation of a blocked polyurethane prepolymer, which is characterized in that the unsaturated pyridinium inner salt refers to N- (3-formyl 4-negative oxygen benzyl) -4-vinyl pyridinium inner salt, and the preparation method is realized by the following steps: weighing 5-chloromethyl salicylaldehyde, 4-vinylpyridine and hydroquinone, dissolving in a solvent to respectively prepare a 5-chloromethyl salicylaldehyde solution and a 4-vinylpyridine mixed hydroquinone solution, controlling the temperature to be 0-100 ℃, adding the 5-chloromethyl salicylaldehyde solution into the 4-vinylpyridine mixed hydroquinone solution, and stirring for reaction for 2-20 hours to prepare N- (3-formyl 4-hydroxybenzyl) -4-vinylpyridinium chloride salts; and then adding an alkali reagent, continuously stirring for reacting for 2-12 hours, and performing rotary evaporation to recover the solvent and the alkali reagent to obtain the N- (3-formyl 4-negative oxygen benzyl) -4-vinylpyridinium inner salt, wherein the specific reaction process is shown in the following reaction formula (c):

wherein the alkali reagent is selected from one of triethylamine, tributylamine, 4-dimethylamino pyridine, N, N, N ', N ' -tetramethyl ethylenediamine, triethylene diamine, N, N ' -dimethyl piperazine or N-methyl morpholine.

The molar usage of the 5-chloromethyl salicylaldehyde, the 4-vinylpyridine and the alkali reagent is 1: 1-1.05: 1-1.5; the dosage of the hydroquinone is 0.1-0.3% of the mass dosage of the 4-vinylpyridine.

The solvent is one or more than two of acetone, butanone, cyclohexanone, tetrahydrofuran, 1, 4-dioxane, chlorobenzene, chloroform, 1, 2-dichloroethane, toluene, xylene, decalin, methyl acetate, ethyl acetate, butyl acetate, N-methylpyrrolidone, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, N, N-dimethylformamide, N, N-dimethylacetamide, triethylamine, tributylamine, p-dimethylaminopyridine, N, N, N ', N ' -tetramethylethylenediamine, triethylene diamine, N, N ' -dimethylpiperazine, N-methylmorpholine or dimethyl sulfoxide, and the solvent is used

The amount of the catalyst is 0.5-5 times of the total mass of the 5-chloromethyl salicylaldehyde and the 4-vinylpyridine.

The unsaturated pyridinium inner salt used as the blocking agent of the isocyanate-terminated polyurethane prepolymer has the following advantages:

the unsaturated pyridinium inner salt is an unsaturated quaternary ammonium salt, can generate polymerization reaction to generate polyquaternary ammonium salt under the heated condition, and can also perform graft polymerization reaction with organic materials to endow the organic materials with hydrophilic antibacterial function. It is used as a polymerizable blocking agent for the isocyanate-terminated polyurethane prepolymer and has similar functions and effects as the isocyanate-terminated polyurethane prepolymer.

The preparation process of the unsaturated pyridinium inner salt is simple, side reactions are few, the product yield is high, the used raw materials are cheap, and the unsaturated pyridinium inner salt is not required to be separated from a preparation reaction system and can be directly used in the sealing process of the isocyanate-terminated polyurethane prepolymer. Wherein, the used alkali reagent is still the alkali reagent after the sealing process is finished, which is convenient for separating and recycling.

And thirdly, after the process of sealing the end of the isocyanate-based polyurethane prepolymer is finished, separating the isocyanate-based polyurethane prepolymer with the sealed end of the unsaturated pyridinium inner salt from the reaction system by adopting a two-solvent precipitation method.

Detailed Description

The following specific examples illustrate the use of an unsaturated pyridinium inner salt in the preparation of a blocked polyurethane prepolymer.

EXAMPLE 1 preparation of blocked polyurethane prepolymer-1

According to the NCO/OH molar ratio of 2.08, 87 g of toluene diisocyanate and 60 g of dehydrated acetone are weighed and placed into a reactor, under the protection of nitrogen, 120 g of hydroxyl-terminated polyethylene glycol monomethyl ether with the mass-average molecular weight of 2000, 120 g of single-ended hydroxyl polyvinylpyrrolidone with the mass-average molecular weight of 2000, 120 g of a mixture of hydroxyl-terminated polyether quaternary ammonium salt of formula (III-1), 2.5 g of stannous octoate and 5 g of 4-dimethylaminopyridine are added under stirring, the temperature is increased to 50-60 ℃ for reaction for 2-4 hours, and after the NCO content reaches 10.2% through the detection of a di-n-butylamine titration method, the solution of the polyurethane prepolymer is prepared for later use.

Weighing 55 g of 4-vinylpyridine and 0.13 g of hydroquinone, mixing the mixture with 40 g of N, N-dimethylformamide, putting the mixture into a reaction kettle, controlling the temperature of materials in the reaction kettle to be 20-25 ℃, slowly adding 150 g of N, N-dimethylformamide solution containing 85 g of 5-chloromethyl salicylaldehyde, stirring and reacting for 10 hours under the protection of nitrogen, then adding 80 g of 4-dimethylaminopyridine, and continuously stirring and reacting for 6 hours to obtain the solution of the N- (3-formyl 4-negative oxygen radical benzyl) -4-vinylpyridinium inner salt, wherein the solution is used for standby without separation.

Putting the prepared polyurethane prepolymer solution and the solution of N- (3-formyl 4-negative oxygen benzyl) -4-vinylpyridinium inner salt into a reaction kettle, controlling the reaction temperature to be 85-90 ℃, stirring and reacting under the protection of nitrogen until no-NCO is detected, and taking 16 hours approximately, and then performing rotary evaporation or negative pressure rotary evaporation to respectively recover acetone, N-dimethylformamide and 4-dimethylaminopyridine. Then adding 300 g of N, N-dimethylformamide into a reaction kettle to just dissolve the residual solids in the reaction kettle, then adding 1000 g of butyl acetate, uniformly stirring, standing for layering, and recovering an upper clear solution, wherein a lower layer is the beige waxy closed polyurethane prepolymer-1, N₂The shelf life of the product can reach more than 12 months after the product is stored in a protective and closed way. Further analytical tests showed that the deblocking temperature was about 105 ℃; at normal temperature, the blocked polyurethane prepolymer-1 is miscible with water in any proportion.

Wherein the hydroxyl-terminated polyether quaternary ammonium salt of the formula (III-1) has the following structure:

。

example 2 preparation of blocked polyurethane prepolymer-2

According to the method and operation steps of example 1, the toluene diisocyanate in example 1 is changed to 1, 6-hexamethylene diisocyanate, and the hydroxyl terminated polyether quaternary ammonium salt with the structure shown in formula (III-1) is changed to the hydroxyl terminated polyether quaternary ammonium salt with the structure shown in formula (III-2), so as to prepare the blocked polyurethane prepolymer-2. The analysis and detection result shows that the deblocking temperature is about 105 ℃; at normal temperature, the blocked polyurethane prepolymer-2 and water can be mixed and dissolved in any proportion, and the water solution of the blocked polyurethane prepolymer-2 can be sealed and stored for more than 12 months.

Wherein the hydroxyl-terminated polyether quaternary ammonium salt of the formula (III-2) has the following structure:

。

EXAMPLE 3 preparation of blocked polyurethane prepolymer-3

According to the method and operation steps of example 1, the toluene diisocyanate in example 1 is changed to diphenylmethane diisocyanate, the hydroxyl terminated polyethylene glycol monomethyl ether with a mass average molecular weight of 2000 is changed to hydroxyl terminated polyethylene glycol monolauryl ether with a mass average molecular weight of 6000, the single-ended hydroxyl polyvinylpyrrolidone with a mass average molecular weight of 2000 is changed to single-ended hydroxyl polyvinylpyrrolidone with a mass average molecular weight of 3800, and the hydroxyl terminated polyether quaternary ammonium salt with a structure shown in formula (III-1) is changed to the hydroxyl terminated polyether quaternary ammonium salt with a structure shown in formula (III-2), so as to prepare the blocked polyurethane prepolymer-3. The analysis and detection result shows that the deblocking temperature is about 105 ℃; at normal temperature, the blocked polyurethane prepolymer-3 can be dissolved in water, and the quality guarantee period of a 32% blocked polyurethane prepolymer-3 aqueous solution in percentage by mass can be more than 6 months after closed storage.

Wherein the hydroxyl-terminated polyether quaternary ammonium salt of the formula (III-2) has the following structure:

。

EXAMPLE 4 preparation of blocked polyurethane prepolymer-4

According to the method and operation steps of example 1, the toluene diisocyanate in example 1 is changed to isophorone diisocyanate, the hydroxyl terminated polyethylene glycol monomethyl ether with a mass average molecular weight of 2000 is changed to hydroxyl terminated polyethylene glycol monolauryl ether with a mass average molecular weight of 6000, the single-ended hydroxyl polyvinylpyrrolidone with a mass average molecular weight of 2000 is changed to single-ended hydroxyl polyvinylpyrrolidone with a mass average molecular weight of 3800, and the hydroxyl terminated polyether quaternary ammonium salt with a structure shown in formula (III-1) is changed to the hydroxyl terminated polyether quaternary ammonium salt with a structure shown in formula (III-3), so that the blocked polyurethane prepolymer-4 is prepared. The analysis and detection result shows that the deblocking temperature is about 105 ℃; at normal temperature, the blocked polyurethane prepolymer-3 can be dissolved in water, and the blocked polyurethane prepolymer-3 aqueous solution with the mass percentage concentration of 35 percent can be stored in a closed manner for more than 6 months.

Wherein the hydroxyl-terminated polyether quaternary ammonium salt of the formula (III-3) has the following structure:

example 5 examples 1-4 germicidal Properties of blocked polyurethane prepolymers

According to the technical requirements and methods of GB/T15979-2002, the blocked polyurethane prepolymer aqueous solutions of examples 1-4 with mass concentrations of 100, 200, 400 and 800mg/L are prepared, and the bactericidal performance is measured, and the results are shown in Table 1.