阅读说明：本技术 一种环保型含氟水性聚氨酯的制备方法 (preparation method of environment-friendly fluorine-containing waterborne polyurethane ) 是由 李兴建 于 2019-09-29 设计创作，主要内容包括：本发明公开了一种环保型含氟水性聚氨酯的制备方法,包括步骤：通过巯基-炔点击化学反应在炔基功能化聚氨酯的每个炔基上引入两个含氟侧链得到含氟侧链聚氨酯、将所述含氟侧链聚氨酯经乳化后得到环保型含氟水性聚氨酯；所述含氟侧链聚氨酯的含氟侧链的碳原子数小于8个。本发明采用水作溶剂,具有合成步骤简单高效、无甲醛无苯类溶剂、无生物蓄积性、无毒性的特点；本发明的环保型含氟水性聚氨酯是一种多功能、绿色环保的防水、防污多功能涂层和织物整理剂,可应用于航空航天、纺织、皮革、包装和建筑等领域。(The invention discloses a preparation method of environment-friendly fluorine-containing waterborne polyurethane, which comprises the steps of introducing two fluorine-containing side chains to each alkynyl of alkynyl functionalized polyurethane through a sulfydryl-alkyne click chemical reaction to obtain fluorine-containing side chain polyurethane, and emulsifying the fluorine-containing side chain polyurethane to obtain the environment-friendly fluorine-containing waterborne polyurethane, wherein the carbon atom number of the fluorine-containing side chain polyurethane is less than 8.)

The preparation method of environment-friendly fluorine-containing waterborne polyurethane is characterized by comprising the steps of introducing two fluorine-containing side chains to each alkynyl of alkynyl functionalized polyurethane through a mercapto-alkyne click chemical reaction to obtain fluorine-containing side chain polyurethane, and emulsifying the fluorine-containing side chain polyurethane to obtain the environment-friendly fluorine-containing waterborne polyurethane, wherein the number of carbon atoms of the fluorine-containing side chains of the fluorine-containing side chain polyurethane is less than 8.

2. The method for preparing Environment-friendly fluorine-containing waterborne polyurethane as claimed in claim 1, wherein the manner of introducing two fluorine-containing side chains to each alkynyl is achieved by thiol-alkyne click chemistry reaction between each alkynyl and two fluorine-containing thiols.

3. The preparation method of environmental friendly fluorine-containing waterborne polyurethane as claimed in claim 2, wherein the fluorine-containing thiol is HS-R_fWherein R is_fThe number of fluorine-containing carbons in (a) is less than or equal to six.

4. The preparation method of Environment-friendly fluorine-containing waterborne polyurethane as claimed in claim 1, wherein the preparation of alkynyl functional polyurethane comprises the steps of mixing polyurethane soft segment polyol, alkynyl functional polyol, polyurethane hard segment isocyanate and solvent, reacting with catalyst under nitrogen protection to obtain isocyanate terminated polyurethane prepolymer, and reacting the isocyanate terminated polyurethane prepolymer with chain extender to obtain alkynyl functional polyurethane.

5. The method for preparing environmental friendly fluorine-containing aqueous polyurethane of claim 4, wherein the alkynyl group functionalized polyol is a polyol having an alkynyl group as a pendant group or a polyol polymer having an alkynyl group.

6. The method for preparing environment-friendly fluorine-containing waterborne polyurethane as claimed in claim 4, wherein the polyurethane hard segment isocyanate is diisocyanate monomer, and the diisocyanate monomer is toluene diisocyanate and isophorone diisocyanate.

7. The preparation method of Environment-friendly fluorine-containing waterborne polyurethane as claimed in claim 1, wherein the preparation method of environment-friendly fluorine-containing waterborne polyurethane comprises the steps of adding fluorine-containing mercaptan into alkynyl functionalized polyurethane, reacting under the action of a catalyst, and adding water under the condition of neutral pH value to emulsify to obtain environment-friendly fluorine-containing waterborne polyurethane.

8. The method for preparing environmental friendly fluorine-containing aqueous polyurethane as claimed in claim 7, wherein the fluorine-containing thiol is or more of 4,4,5,5, 5-pentafluoropentanethiol, nonafluoropentanethiol, perfluorohexylethanethiol and perfluorohexylpropanethiol.

9. The method for preparing environment-friendly fluorine-containing aqueous polyurethane of any one of claims 1 to 8 and , which comprises the step of reacting the environment-friendly fluorine-containing aqueous polyurethane with a modified nanomaterial based on lotus leaf effect to obtain the modified environment-friendly fluorine-containing aqueous polyurethane.

10. The method for preparing Environment-friendly fluorine-containing waterborne polyurethane of claim 9, wherein the modified nanomaterial is silane coupling agent or polymer material modified nano-silica.

Technical Field

The invention belongs to the technical field of waterborne polyurethane, and particularly relates to a preparation method of environment-friendly fluorine-containing waterborne polyurethane.

Background

The fluorine-containing side chain has the characteristics of small atomic radius, large electronegativity and small polarizability, and when the fluorine-containing side chain and a carbon atom form a covalent bond C-F, the covalent bond has large bond length and small bond energy, stable molecular structure and good thermal stability and chemical stability. Meanwhile, the fluorine-containing side chain core has strong binding effect on extra-nuclear electrons and bonding electron clouds, the polarizability of the C-F bond is low, and the intermolecular force of the polymer containing the C-F bond is low, so that the fluorine-containing polymer has extremely low surface energy, excellent water resistance, oil resistance and stain resistance.

Among the numerous coating materials, polyurethane materials have excellent properties. The fluorine-containing polyurethane is prepared by introducing the fluorine polymer into the polyurethane, so that the original characteristics of the polyurethane are maintained, and the polyurethane is endowed with excellent weather resistance, chemical medium resistance, pollution resistance and low friction; therefore, the method has a wide application prospect in the industries of coating industry products, leather finishing materials, fabric finishing agents, biomedicine and the like. Meanwhile, the incorporation of a fluoropolymer into an aqueous polyurethane is expected to eliminate the disadvantage that the water resistance of a coating film is lowered due to hydrophilic modification of the polyurethane, in addition to imparting excellent surface properties to the coating film.

The raw materials for preparing the fluorine-containing polyurethane mainly comprise fluoroalkyl alcohols, fluorine-containing isocyanate, fluorine-containing glycols, fluoroalkyl methacrylate and the like. Wherein, most of the fluorine-containing materials are complex to prepare, high in cost and difficult to obtain. However, the fluorine-containing monomers used in large amounts at present are long fluorocarbon chains (C.gtoreq.8), such as perfluorooctylsulfonyl compounds (PFOS) and perfluoroalkyl (meth) acrylates, which are industrial products. Because they are difficult to degrade in the environment, have the characteristics of strong bioaccumulation and long-distance mobility, have potential risks to human health and environment, and are strictly limited by various countries. Researches find that the short fluorocarbon chain (C is less than or equal to 6) compound can not cause the problem of environmental pollution because the chain segment of the compound is easy to degrade in the environment.

From the aspect of water and oil repellent performance, for longer fluorocarbon chains (C is more than or equal to 8), due to the chain length, the fluorocarbon chains have better mobility and good crystallinity, so that more fluorine elements can be stably positioned on the surface of the material, and the surface has better water and oil repellent performance. And the fluoropolymer with the C less than or equal to 6 is in a slightly collapsed state on the surface, so that the stability of the fluorine chain segment on the surface of the material is influenced, and the water and oil repellent performance of the whole polymer is adversely affected.

From the viewpoint of the manner of introduction of the fluorine-containing segment, the fluorine-containing segment may be introduced into the main chain and the side chain of the polyurethane. But due to the action of hydrogen bonds between longer polyurethane main chains, the migration capability of the fluorine-containing chain segment of the main chain to the surface is inhibited in the drying film-forming process, and the improvement of the hydrophobicity of the film surface is limited. The fluorine-containing chain segment is positioned on the polyurethane side chain, so that the movement capacity of the chain segment is increased, the crystallization capacity of the fluorine chain segment is favorably enhanced, and the hydrophobicity and the durability of the material are improved.

Click Chemistry (Click Chemistry) reaction has the characteristics of rapidness, high efficiency, insensitivity to water and oxygen, raw material sources, high tolerance to active groups, high yield, high selectivity and the like, and like a Click mouse , the Click mouse has the characteristics of universality, simplicity and modularization, and has been widely applied to synthesis and modification of various comb-type polymers, star-like polymers, dendritic polymers and hyperbranched polymers.

However, on the premise of keeping the product economy, how to improve the migration capacity and crystallinity of the short fluorine chain segment so as to obviously improve the surface performance of the polyurethane is difficult problems to be solved, general and effective methods for improving the efficiency of the short fluorine chain segment are not developed yet, therefore, efficient, general and simple methods for preparing the environment-friendly water-based polyurethane containing the short fluorine chain and being biodegradable have important significance.

Disclosure of Invention

In order to solve the problems in the prior art, the invention aims to provide a preparation method of environment-friendly fluorine-containing waterborne polyurethane, wherein the environment-friendly fluorine-containing waterborne polyurethane obtained by the preparation method is environment-friendly side chain fluorine-containing polyurethane with water resistance and oil resistance, the environment-friendly fluorine-containing waterborne polyurethane can replace long fluorine chain segment polyurethane to play an environment-friendly role, and more excellent water and oil repellency is endowed to the polyurethane by improving the migration capacity and density of the fluorine chain segment.

The technical scheme adopted by the invention is as follows:

A preparation method of environment-friendly fluorine-containing waterborne polyurethane comprises the steps of introducing two fluorine-containing side chains to each alkynyl of alkynyl functionalized polyurethane through a thiol-alkyne click chemical reaction to obtain fluorine-containing side chain polyurethane, and emulsifying the fluorine-containing side chain polyurethane to obtain the environment-friendly fluorine-containing waterborne polyurethane, wherein the number of carbon atoms of the fluorine-containing side chains of the fluorine-containing side chain polyurethane is less than 8.

Further , the introduction of two fluorine-containing side chains per alkynyl group is achieved by thiol-alkyne click chemistry of each alkynyl group with two fluorine-containing thiols.

, the fluorine-containing mercaptan is HS-R_fWherein R is_fThe number of fluorine-containing carbons in (a) is less than or equal to six.

, the preparation of alkynyl functional polyurethane comprises mixing polyurethane soft segment polyol, alkynyl functional polyol, polyurethane hard segment isocyanate and solvent, reacting with catalyst under nitrogen protection condition to obtain isocyanate end-capped polyurethane prepolymer, and reacting the isocyanate end-capped polyurethane prepolymer with chain extender to obtain alkynyl functional polyurethane.

Further , the alkynyl functionalized polyol is an alkynyl containing polyol or an alkynyl containing polyol polymer having an alkynyl group as a pendant group.

, the hard polyurethane isocyanate is diisocyanate monomer, which is toluene diisocyanate and isophorone diisocyanate.

, adding fluorine-containing mercaptan into the alkynyl functional polyurethane, reacting under the action of a catalyst, and adding water under a neutral pH value condition for emulsification to obtain the environment-friendly fluorine-containing waterborne polyurethane.

Further , the fluorine-containing mercaptan is or more of 4,4,5,5, 5-pentafluoropentanethiol, nonafluoropentanethiol, perfluorohexylethanethiol, and perfluorohexylpropanethiol.

, reacting the environment-friendly fluorine-containing waterborne polyurethane with the modified nano-material based on lotus leaf effect to obtain the modified environment-friendly fluorine-containing waterborne polyurethane.

, the modified nanometer material is silane coupling agent or nanometer silicon dioxide modified by high molecular material.

The invention has the beneficial effects that: the environment-friendly fluorine-containing waterborne polyurethane disclosed by the invention has the advantages that the number of carbon atoms of a fluorine-containing side chain is less than 8, so that the mobility of the fluorine-containing side chain is facilitated, the fluorine-containing side chain is vertically arranged on the outermost layer of a polymer-air interface, the density of the fluorine-containing chain segment can be increased, and the water and oil repellent capacity and the surface performance stability of the material are enhanced.

The fluorine-containing side chain of the environment-friendly fluorine-containing waterborne polyurethane prepared by the preparation method is short chain, can replace the traditional long-fluorine chain segment polyurethane to play a role, and the high-density short-fluorine carbon chain is introduced into the polyurethane side chain through sulfydryl-alkyne click chemistry, so that the problems of bioaccumulation and environment existing in the long-fluorine carbon chain can be well solved while the excellent water repellency of the long-fluorine carbon chain is maintained, and the problem that the traditional long-fluorine chain segment polyurethane pollutes the environment is solved.

Drawings

FIG. 1 shows DPPD obtained in example 1¹H NMR spectrum.

FIG. 2 is a FT-IR spectrum of DPPD obtained in example 1.

FIG. 3 shows the FT-IR spectrum of the alkynyl functionalized polyurethane obtained in example 1.

FIG. 4 shows the preparation of the side chain fluoroanion-containing aqueous polyurethane obtained in example 1¹H NMR spectrum.

Fig. 5 is a schematic representation of the surface of the fabric of the present invention.

FIG. 6 is a schematic representation of the water uptake of the treated fabric of the present invention.

FIG. 7 is a schematic diagram of the preparation of alkynyl functionalized polytetrahydrofuran diol in example 3.

FIG. 8 is a scanning electron microscope image of the environmentally friendly fluorine-containing aqueous polyurethane before and after modification of the nano-silica.

FIG. 9 is a schematic view of the principle of the preparation method of the present invention.

FIG. 10 is a schematic representation of the molecular structure of 6 alternative species of the diol of FIG. 8.

Detailed Description

The invention is further illustrated in below with reference to the following figures and examples.

The alkynyl functional polyurethane in the present specification is a polyurethane having an alkynyl group in a side chain.

A preparation method of environment-friendly fluorine-containing waterborne polyurethane comprises the steps of introducing two fluorine-containing side chains to each alkynyl of alkynyl functionalized polyurethane through a thiol-alkyne click chemical reaction to obtain fluorine-containing side chain polyurethane, and emulsifying the fluorine-containing side chain polyurethane to obtain the environment-friendly fluorine-containing waterborne polyurethane, wherein the number of carbon atoms of the fluorine-containing side chains of the fluorine-containing side chain polyurethane is less than 8.

The object of the present invention is to provide water-resistant, oil-resistant, environmentally friendly, side-chain fluorinated waterborne polyurethanes, which can replace long fluorinated chain segment polyurethanes to achieve environmental protection, and impart more excellent water-and oil-repellency to polyurethanes by increasing the migration ability and density of the fluorinated chain segment, the inventive principle is shown in fig. 9 and 10.

Wherein, the polyurethane can be isocyanate, the isocyanate can be polyurethane hard isocyanate, the diol comprises types of diol macromolecules and hard segment micromolecule diols which are polyurethane soft segments, types of diol macromolecules and hard segment micromolecule diols which are polyurethane soft segments containing alkynyl groups, and the fluorine-containing thiol is HS-R_fWherein R is_fThe number of fluorine-containing carbon in (b) is less than or equal to six.

The isocyanate before polymerization may be kinds or a mixture of two or more kinds of aromatic diisocyanate and aliphatic diisocyanate.

The diol monomer before polymerization may be macrodiol constituting part of the soft polyurethane segment, and may be kinds or mixture of two or more kinds of polyether polyol, polyester polyol, polyacrylate polyol and vegetable oil polyol.

The diol monomer before polymerization may be functional monomer diol introduced with alkynyl group, and may be kinds or mixture of two or more kinds of diol macromolecules containing alkynyl group and diol micromolecules containing alkynyl group.

HS-R of fluorine-containing mercaptan before polymerization_fCan be R_f or a mixture of two or more of the fluoroalkyl thiols (with the number of fluorine-containing carbon(s) in (b) being equal to or less than six.

Further , the introduction of two fluorine-containing side chains per alkynyl group is achieved by thiol-alkyne click chemistry of each alkynyl group with two fluorine-containing thiols.

, the fluorine-containing mercaptan is HS-R_fWherein R is_fThe number of fluorine-containing carbons in (a) is less than or equal to six.

, the preparation of alkynyl functional polyurethane comprises mixing polyurethane soft segment polyol, alkynyl functional polyol, polyurethane hard segment isocyanate and solvent, reacting with catalyst under nitrogen protection condition to obtain isocyanate end-capped polyurethane prepolymer, and reacting the isocyanate end-capped polyurethane prepolymer with chain extender to obtain alkynyl functional polyurethane.

Specifically, the preparation of the alkynyl functionalized polyurethane comprises the following steps: (1) under the protection of nitrogen, uniformly mixing polyurethane soft segment polyol, alkynyl functional polyol and polyurethane hard segment isocyanate, adding a proper amount of solvent for dilution, adding a catalyst, and reacting at 90 ℃ for about 2 hours to obtain the PU prepolymer capped by isocyanate. Reducing the temperature of a reaction system to 45 ℃, adding a hydrophilic chain extender and a common chain extender, uniformly stirring, raising the reaction temperature to 80 ℃, and reacting for 6-8 hours to obtain hydrophilic alkynyl functional polyurethane; the molar ratio of isocyanate groups to hydroxyl groups in all monomers was 1.2: 1.

After the reaction in the step (1) is finished, the reaction temperature is reduced to 50-120 ℃, a catalyst is added, and then a mercaptan monomer with a short fluorocarbon chain, namely fluorine-containing mercaptan, is added for reaction for 1-2 hours. And adding a neutralization salt forming agent after the reaction is finished, adding water for emulsification, and removing the organic solvent to obtain the environment-friendly fluorine-containing waterborne polyurethane.

If the chain extender used in the reaction step (1) contains carboxyl groups, neutralizing a salt forming agent by using inorganic base or organic base, such as ammonia water, triethylamine, triethanolamine, sodium hydroxide and the like, to adjust the pH value to be neutral to obtain the anion graft modified aqueous fluorine-containing polyurethane; the chain extender is diethylenetriamine, diethanolamine, triethanolamine, triethylene tetramine, tetraethylenepentamine and the like, and inorganic acid or organic acid is used for neutralizing a salt forming agent, such as hydrochloric acid, sulfuric acid, acetic acid, oxalic acid and the like, so as to adjust the pH value to be neutral, and obtain the cationic waterborne polyurethane.

, the polyurethane soft segment is polyether diol, polytetrahydrofuran ether diol, polycaprolactone polyol or polycarbonate diol.

Further , the alkynyl functionalized polyol is an alkynyl containing polyol or an alkynyl containing polyol polymer having an alkynyl group as a pendant group.

And , the alkynyl functional polyol is 4, 4' -dimethylol-1, 4-heptadiyne, 2-dipropynyl-1, 3-propanediol, monopropargyl pentaerythritol or alkynyl-containing polyether polyol.

, the hard polyurethane isocyanate is diisocyanate monomer, which is toluene diisocyanate and isophorone diisocyanate.

, in the preparation step of the alkynyl functional polyurethane, the mol ratio of all isocyanic acid radicals to all hydroxyl groups is 1.2:1, the solvent is or a mixture of several of N, N-dimethylformamide, N-methylpyrrolidone and acetone, and the catalyst is dibutyltin dilaurate.

, adding fluorine-containing mercaptan into the alkynyl functional polyurethane, reacting under the action of a catalyst, and adding water under a neutral pH value condition for emulsification to obtain the environment-friendly fluorine-containing waterborne polyurethane.

Further , the fluorine-containing mercaptan is or more selected from the group consisting of 4,4,5,5, 5-pentafluoropentanol, nonafluoropentanol, perfluorohexylethanethiol, and perfluorohexylpropanethiol.

, the catalyst in the preparation step of the environment-friendly fluorine-containing waterborne polyurethane is of radical initiator, alkali catalyst or ultraviolet initiator.

The free radical initiator may be cyclohexanone peroxide, dibenzoyl peroxide, tert-butyl hydroperoxide, azobisisobutyronitrile or azobisisoheptonitrile, the alkali catalyst may be triethylamine, 4-dimethylaminopyridine, n-butylamine, tributylamine, triethanolamine, 1, 8-diazabicyclooctane deca C-7-ene or 1,5, 7-triazabicyclo [4.4.0] dec-5-ene, and the ultraviolet initiator may be 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-2- (4-morpholinyl) -1- [4- (methylthio) phenyl ] -1-propanone, 2,4, 6-trimethylbenzoyl-diphenylphosphine oxide or 2-hydroxy-2-methyl-1- [4- (2-hydroxyethoxy) phenyl ] -1-propanone.

, reacting the environment-friendly fluorine-containing waterborne polyurethane with the modified nano-material based on lotus leaf effect to obtain the modified environment-friendly fluorine-containing waterborne polyurethane.

, the modified nanometer material is silane coupling agent or nanometer silicon dioxide modified by high molecular material.

The technical schemes provided by the invention are as follows:

the environment-friendly fluorine-containing waterborne polyurethane, wherein all side chains of the environment-friendly fluorine-containing waterborne polyurethane are fluorine-containing side chains with carbon atom number less than 8.

The specific performance test of the environment-friendly fluorine-containing waterborne polyurethane is carried out according to the following method:

infrared spectrum analysis: infrared spectroscopy is carried out by a Nicolet MX-1E type infrared spectrometer.

Nuclear magnetic hydrogen spectrum analysis: nuclear magnetic hydrogen spectroscopy (300MHz) using a Bruker AMX300 nuclear magnetic resonance apparatus¹HNMR) and fluorine spectra (¹⁹F NMR).

Surface analysis: performing electron microscope analysis on the membrane surface and the fabric surface by adopting a JSM-7500F type scanning electron microscope, and performing element analysis on the membrane surface by using an own energy spectrum analyzer (EDS).

Water repellency test, namely, a Bundy spray instrument of Changzhou second textile machinery, Inc. is adopted to test the water repellency, according to the national standard GB-T4745-1977, the water repellency of a wet sample is evaluated into 5 grades, namely, a sprayed surface is not wetted and small water drops are not occupied on the surface, 4 grades, namely, the sprayed surface is not wetted but small water drops are occupied on the surface, 3 grades, only unconnected small areas of the sprayed surface are wetted, 2 grades, semi-wetted surfaces and 1 grade, namely, the whole surface is fully wetted.

Water contact angle: the water contact angle test was carried out using a DSA100 type water contact angle measuring instrument.

Water absorption test: the water absorption test adopts a soaking method, the textile film is weighed and recorded as m₁Then soaking in deionized water, taking out periodically, quickly drying the water on the surface of the fabric by using filter paper, and weighing to m₂Water absorption (%) is (m)₂－m₁)/m₁×100％。