CN106977690A - A kind of phosphonitrile type light-cured polyurethane resin of ring three and its coatings of preparation - Google Patents

Abstract

The invention discloses a cyclotriphosphazene-type light-curing polyurethane resin and a self-repairing coating prepared therefrom. Firstly, dihydric alcohol and diisocyanate react; then react with light-curable monomers to introduce double bonds; The phosphazene monomer reacts to prepare the cyclotriphosphazene photocurable polyurethane resin; the photocurable polyurethane resin, photoinitiator, active diluent and solvent are mixed to form a self-healing coating. The preparation method of the invention is simple, the reaction conditions are mild, the contained carbon-carbon double bonds can be used for the photocuring performance of the coating, the hydrogen bonds between isocyanates can be used for the self-healing performance, and the introduction of the cyclotriphosphazene inner core makes it have better Hardness and mechanical properties, and at the same time make it have self-healing properties, and the cooperation of various raw materials makes a self-healing coating with excellent performance.

Description

A cyclotriphosphazene-type light-cured polyurethane resin and self-healing coating prepared therefrom

technical field

The invention relates to the technical field of light-curing materials, in particular to a cyclotriphosphazene-type light-curing polyurethane resin prepared by reacting a cyclotriphosphazene monomer and a polyurethane prepolymer, and its application in self-repair.

Background technique

Self-healing coating refers to a functional coating that has self-healing ability after the coating is damaged, or has self-healing ability under certain external environment. As a novel intelligent structural functional material, self-healing polymer materials can avoid further damage to materials by realizing self-healing of microcracks. Self-healing principles mainly include two categories: extrinsic type (microcapsule repair type, hollow fiber type) and intrinsic type (reversible covalent bond type, reversible non-covalent bond type). The external self-healing can only be repaired once, which greatly limits its wide application in the coating field, while the intrinsic self-healing can be used for multiple repairs due to its repair characteristics. However, most of the previous coatings use single-arm or less The arm structure leads to its low hardness and poor mechanical properties, which greatly limits its practical application.

Cyclotriphosphazene is a kind of organic-inorganic hybrid material with phosphorus atoms and nitrogen atoms arranged alternately through single and double construction. It can be divided into cyclophosphazene and polyphosphazene. Representative compounds, structurally, the phosphorus atom connects two active groups that can be replaced, which are easily attacked by nucleophiles and replaced, which can endow the material with excellent hardness and thermal stability. Therefore, it is modified as the polyol structure of synthetic polyurethane and introduced into the benzene ring structure, while ensuring its self-healing performance, it improves the hardness and mechanical properties of the self-healing coating prepared by it.

Contents of the invention

In view of the above-mentioned problems existing in the prior art, the applicant of the present invention provides a cyclotriphosphazene type photocurable polyurethane resin and a self-healing coating prepared therefrom. The present invention grafts photocurable double bond groups onto cyclotriphosphazene to prepare cyclotriphosphazene photocurable polyurethane resin, which greatly improves the self-healing coating while ensuring good self-repairing performance. Hardness; the introduction of photosensitive groups can not only achieve high-efficiency UV curing, but also improve the mechanical properties of the coating.

Technical scheme of the present invention is as follows:

A kind of cyclotriphosphazene type photocurable polyurethane resin, the preparation method of described resin comprises the steps:

(1) Dilute the diisocyanate and the catalyst dibutyltin dilaurate with an anhydrous solvent and place them in the reactor, then add the dibasic alcohol diluted with an anhydrous solvent dropwise into the reactor, and react at 40-50°C for 2- 4h, obtained isocyanate-terminated prepolymer;

(2) Then, dropwise add a photocurable monomer to the isocyanate-terminated prepolymer obtained in step (1), stir and react at 60-70°C for 5-7h, to obtain a photosensitive polyurethane solution;

(3) Finally, dissolve the cyclotriphosphazene monomer and the catalyst dibutyltin dilaurate in an anhydrous solvent, slowly add it dropwise to the photosensitive polyurethane solution obtained in step (2), and react with stirring at 50-70°C for 10-12h, After the reaction is completed, the product is precipitated in deionized water, suction filtered, and vacuum-dried to obtain the cyclotriphosphazene-type photocurable polyurethane resin.

The diisocyanate described in step (1) is diphenylmethane diisocyanate, polymerized diphenylmethane diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate One or more in; The dibasic alcohol is PEG-400, PEG-800, PEG-1000, PEG-2000, PEG-10000, T5650E, T5650J, T5651, T5652, polyethylene oxide (polyethylene oxide) Diol) diol, polypropylene oxide (polypropylene glycol) diol, polytetrahydrofuran diol, polyethylene adipate diol, poly(1,4-butylene adipate) diol One or more; the molar ratio of the diisocyanate to the glycol is 2-2.2:1.

The dosage of the catalyst dibutyltin dilaurate in step (1) is 0.5-1% of the total mass of dihydric alcohol and diisocyanate.

The photocuring monomer described in step (2) is one or more in (meth)hydroxyethyl acrylate, (meth)hydroxypropyl acrylate, (meth)hydroxybutyl acrylate; The molar ratio of the monomer to the isocyanate-terminated prepolymer is 1˜1.1:1.

The cyclotriphosphazene monomer described in step (3) is a mixture of one or two of hexa-hydroxymethylphenoxy cyclotriphosphazene and dodecahydroxycyclotriphosphazene; the cyclotriphosphazene The molar ratio of monomer to photosensitive polyurethane is 1-1.1:1.

The anhydrous solvent is one or more of N,N-dimethylformamide, acetone, anhydrous methyl ethyl ketone, tetrahydrofuran, ethyl acetate; the amount of the anhydrous solvent is to make the reaction system The concentration of the compound is 20-30wt%.

An application of the cyclotriphosphazene type photocurable polyurethane resin, which can be used in the technical field of self-repair.

A self-repairing coating containing the cyclotriphosphazene type photocurable polyurethane resin, the coating contains raw materials and the mass percentage of each raw material is:

Mix the raw materials according to the above proportions, avoid light and ultrasonically for 30-60 minutes, then spin-coat on the aluminum plate with a thickness of 0.1-1mm, pre-bake at 40-100°C for 60-120 minutes, and then heat at 500-800mJ/ ^cm2 Under the energy of exposure and curing, cyclotriphosphazene type light-cured polyurethane self-healing coating was prepared.

The reactive diluent is one or more of trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate; the photoinitiator is 2-hydroxyl-2-methyl- 1-phenyl-1-propanone, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone, 2-methyl-1- One or more of (4-methylthiophenyl)-2-morpholine-1-acetone; the solvent is N,N-dimethylformamide, butanone, dimethylacetamide, cyclic One or more of hexanone and ethyl acetate.

The beneficial technical effects of the present invention are:

(1) The polyurethane resin in the present invention takes cyclotriphosphazene as the hard core, and grafts a plurality of linear polyurethane soft chains on the cyclotriphosphazene through gradual addition to form a structure of "hard core and soft arms", The benzene ring structure in hexa-hydroxymethylphenoxycyclotriphosphazene can greatly improve the hardness of the polyurethane. At the same time, the multi-arm structure of polyurethane can not only graft more self-healing groups, but also maintain the stability of the chain under heating. Mobility, guaranteed to have better self-healing performance.

(2) The cyclotriphosphazene monomer used in the present invention has simple and easy-to-obtain synthetic raw materials, mature synthetic technology, and simple preparation method.

(3) In the present invention, the photosensitive group contained at the end of the molecular chain of the photocurable polyurethane resin is prepared by adopting ultraviolet curing technology with low curing temperature, fast curing speed, high curing efficiency, easy operation, energy saving and environmental protection to prepare cyclotriphosphazene type Self-healing photocured polyurethane not only simplifies the traditional film-forming process, improves production efficiency, but also enhances mechanical properties by forming a cross-linked network.

Description of drawings

Fig. 1 is a schematic diagram of the reaction process of the present invention;

Fig. 2 is the ultra-depth-of-field microscopic image of (A) and (a) after the repair of the coating described in Example 1;

3 is a TGA graph of the coating described in Example 1.

detailed description

The present invention will be specifically described below in conjunction with the accompanying drawings and embodiments.

Example 1

A kind of cyclotriphosphazene type light-cured polyurethane resin is obtained through the following steps:

(1) Dilute 2.445g (0.011mol) of isophorone diisocyanate and 0.024g of dibutyltin dilaurate with 12.5g of anhydrous N,N-dimethylformamide (DMF) and place in a stirring and condensing In a three-necked flask, a mixture of 12.5 g of anhydrous DMF and 2.5 g (0.005 mol) of PCDL500 was slowly added dropwise to the three-necked flask, and reacted at 45 ° C for 2 h to obtain an isocyanate-terminated prepolymer;

(2) Dissolve 0.651g (0.005mol) of hydroxyethyl methacrylate in 4.4g of anhydrous DMF, add dropwise to the isocyanate-terminated prepolymer prepared in step (1), and react at 60°C 6h, the photosensitive polyurethane solution was obtained;

(3) Dissolve 0.728g (0.000833mol) of hexa-p-hydroxymethylphenoxycyclotriphosphazene and 0.01g of dibutyltin dilaurate in 3.0g of anhydrous DMF, and add dropwise to the photosensitive polyurethane prepared in step (2) In the solution, react at 70° C. for 12 hours. After the reaction is completed, the product is precipitated in deionized water, filtered with suction, and dried in vacuum to obtain the cyclotriphosphazene-type photocurable polyurethane resin.

Mix 60wt% of cyclotriphosphazene type polyurethane resin prepared by the embodiment of the present invention, 3wt% of 1-hydroxycyclohexyl phenyl ketone and 37wt% of DMF, and then spin-coat it on an aluminum plate after 30 minutes of ultrasound in the dark, with a thickness of 0.3mm, at 70°C, pre-baked for 120min, and then exposed and cured under the energy of 600mJ/cm ² to prepare cyclotriphosphazene-type photocurable polyurethane self-healing coating.

After scratching the surface of the prepared cyclotriphosphazene photocurable polyurethane self-healing coating with a scratch tester, the surface of the coating was heated at 100°C for 10 min with a heat gun, and the coating was observed through a three-dimensional ultra-depth-of-field optical microscope. The self-healing performance of the coating, the comparison before and after the coating is shown in Figure 2, the pendulum hardness (avg) of the coating is 147±3, and the pencil hardness is 2H.

It can be seen from Figure 2 that the scratches disappear obviously after the coating is damaged, showing a good self-healing effect.

It can be seen from Figure 3 that the coating is mainly divided into three thermogravimetric processes, respectively between 220-280°C, 300-400°C and 420-500°C, corresponding to the hard segment structure, soft segment structure and other bonds. Decomposition shows that the prepared polyurethane self-healing coating has good thermal stability.

Example 2

A kind of cyclotriphosphazene type light-cured polyurethane resin is obtained through the following steps:

(1) Use 12g of anhydrous ethyl acetate to dilute 3.532g (0.021mol) of hexamethylene diisocyanate and 0.037g of dibutyltin dilaurate into a three-necked flask with stirring and condensation, and then add A mixture of 15 g of anhydrous ethyl acetate and 4.0 g (0.01 mol) of PEG400 was slowly added dropwise, and the reaction was stirred at 45° C. for 2 h to prepare an isocyanate-terminated prepolymer;

(2) Dissolve 1.301g (0.01mol) of hydroxypropyl acrylate in 5.0g of anhydrous ethyl acetate, slowly add dropwise to the isocyanate-terminated prepolymer prepared in step (1), and react at 60°C Under stirring for 6h, a photosensitive polyurethane solution was obtained;

(3) 1.449g (0.00166mol) hexa-hydroxymethylphenoxycyclotriphosphazene and 0.017g dibutyltin dilaurate were dissolved in 5.0g anhydrous ethyl acetate, and added dropwise to the obtained In the photosensitive polyurethane solution, the reaction was stirred at 70° C. for 12 hours. After the reaction was completed, the product was added dropwise to deionized water to precipitate, filtered by suction, and dried in vacuum to prepare the cyclotriphosphazene-type photocurable polyurethane resin.

50wt% of the photocurable polyurethane prepared by the embodiment of the present invention, 20wt% of triethoxylated trimethylolpropane triacrylate, 27wt% of ethyl acetate and 3wt% of 2-hydroxyl-2-methyl- Mix 1-phenyl-1-acetone, avoid light and ultrasonically for 45 minutes, then spin-coat on an aluminum plate with a thickness of 0.2mm, pre-bake at 40°C for 120 minutes, and then perform exposure curing under the energy of 700mJ/ ^cm2 . A cyclotriphosphazene-type light-cured polyurethane self-healing coating was prepared.

Example 3

A kind of cyclotriphosphazene type light-cured polyurethane resin is obtained through the following steps:

(1) Dilute 2.753g (0.011mol) of diphenylmethylene diisocyanate and 0.035g of dibutyltin dilaurate with 10g of anhydrous methyl ethyl ketone and add them to a three-necked flask with stirring and condensation; A mixture of 15 g of anhydrous methyl ketone and 5.0 g (0.005 mol) of PCDL1000 was slowly added dropwise, and the reaction was stirred at 40 ° C for 3 h to prepare an isocyanate-terminated prepolymer;

(2) Dissolve 0.581g (0.005mol) of hydroxyethyl acrylate in 3.5g of anhydrous methyl ethyl ketone, slowly add dropwise to the isocyanate-terminated prepolymer prepared in step (1), and react at 60°C Stir for 4h to obtain a photosensitive polyurethane solution;

(3) 1.570g (0.000833mol) dodecahydroxycyclotriphosphazene and 0.01g dibutyltin dilaurate are dissolved in 5g anhydrous methyl ethyl ketone, dropwise in the photosensitive polyurethane solution that step (2) makes, react in Stirring at 70° C. for 12 hours, the reaction was completed, the product was added dropwise to deionized water to precipitate, filtered with suction, and dried in vacuum to prepare the cyclotriphosphazene-type photocurable polyurethane resin.

50wt% cyclotriphosphazene type polyurethane resin prepared in the examples of the present invention, 10wt% nonaethoxylated trimethylolpropane triacrylate, 37wt% ethyl acetate, 3wt% 1-hydroxycyclohexylbenzene Mixed methyl ketone, protected from light and ultrasonicated for 60 minutes, spin-coated on an aluminum plate with a thickness of 0.15 mm, pre-baked for 100 minutes at 50 ° C, and then exposed and cured at an energy of 800 mJ/cm ² to prepare cyclotriphosphine Nitrile-based light-curing polyurethane self-healing coating.

Claims (9)

1. a kind of phosphonitrile type light-cured polyurethane resin of ring three, it is characterised in that the preparation method of the resin includes following step Suddenly：

(1) it will be placed in using anhydrous solvent after diisocyanate, the dilution of catalyst dibutyltin dilaurylate in reactor, then The dihydric alcohol of anhydrous solvent dilution is added dropwise into reactor, 2~4h is reacted at 40~50 DEG C, the pre- of isocyanate group end-blocking is made Polymers；

(2) then, photo-curing monomer, 60-70 DEG C of stirring reaction is added dropwise into the prepolymer of isocyanate group end-blocking obtained by step (1) 5-7h, obtains photosensitive polyurethane solution；

(3) finally, the phosphonitrile monomer of ring three and catalyst dibutyltin dilaurylate are dissolved in anhydrous solvent, are slowly dropped to step Suddenly in photosensitive polyurethane solution obtained by (2), 50-70 DEG C of stirring reaction 10-12h, reaction terminates, and product sinks in deionized water Shallow lake, suction filtration, vacuum drying, obtain the phosphonitrile type light-cured polyurethane resin of ring three.

2. the phosphonitrile type light-cured polyurethane resin of ring three according to claim 1, it is characterised in that two described in step (1) Isocyanates is methyl diphenylene diisocyanate, polymeric diphenylmethane diisocyanate, toluene di-isocyanate(TDI), six methylenes One or more in group diisocyanate, IPDI, XDI；The dihydric alcohol For PEG-400, PEG-800, PEG-1000, PEG-2000, PEG-10000, T5650E, T5650J, T5651, T5652, polycyclic Oxidative ethane (polyethylene glycol) glycol, PPOX (polypropylene glycol) glycol, polytetrahydrofuran diol, polyethylene glycol adipate One or more in glycol, polyadipate -1,4- butyl glycol ester diols；The mol ratio of the diisocyanate and dihydric alcohol is 2~2.2:1.

3. the phosphonitrile type light-cured polyurethane resin of ring three according to claim 1, it is characterised in that step is urged described in (1) The consumption of agent dibutyl tin laurate is the 0.5~1% of dihydric alcohol and diisocyanate gross mass.

4. the phosphonitrile type light-cured polyurethane resin of ring three according to claim 1, it is characterised in that light described in step (2) Curing monomer be (methyl) hydroxy-ethyl acrylate, (methyl) hydroxypropyl acrylate, one kind in (methyl) hy-droxybutyl or It is a variety of；The mol ratio for the prepolymer that the photo-curing monomer is blocked with isocyanate group is 1~1.1:1.

5. the phosphonitrile type light-cured polyurethane resin of ring three according to claim 1, it is characterised in that ring described in step (3) Three phosphonitrile monomers are the mixing of one or both of six pairs of phosphonitriles of hydroxymethyl phenoxy basic ring three, the phosphonitriles of ten dihydroxy basic ring three；Institute The mol ratio for stating the phosphonitrile monomer of ring three and photosensitive polyurethane is 1~1.1:1.

6. the phosphonitrile type light-cured polyurethane resin of ring three according to claim 1, it is characterised in that described anhydrous solvent For the one or more in N,N-dimethylformamide, acetone, anhydrous butanone, tetrahydrofuran, ethyl acetate；The anhydrous solvent Consumption be to make the concentration of reactant in reaction system be 20~30wt%.

7. a kind of application containing any one of the claim 1~6 phosphonitrile type light-cured polyurethane resin of ring three, its feature exists It can be used for self-repair technology field in the light-cured polyurethane resin.

8. a kind of coatings containing any one of the claim 1~6 phosphonitrile type light-cured polyurethane resin of ring three, its The mass percent for being characterised by raw material and each raw material contained by the coating is：

Each raw material is mixed according to the above ratio, after 30~60min of lucifuge ultrasound, is spun on aluminium sheet, thickness is 0.1~1mm, Under the conditions of 40~100 DEG C, 60~120min of preliminary drying, then in 500-800mJ/cm²Energy under be exposed solidification, be made ring Three phosphonitrile type light-cured polyurethane coatings.

9. coatings according to claim 8, it is characterised in that the reactive diluent is trimethylolpropane tris One or more in acrylate, ethoxylated trimethylolpropane triacrylate；The light trigger is 2- hydroxyls -2- Methyl isophthalic acid-phenyl -1- acetone, 1- hydroxy-cyclohexyls phenyl ketone, 2- hydroxyls -4 '-(2- hydroxy ethoxies) -2- methyl phenyl ketones, One or more in 2- methyl isophthalic acids-(4- methyl mercaptos phenyl) -2- morpholine -1- acetone；The solvent is N, N- dimethyl formyls One or more in amine, butanone, dimethyl acetamide, cyclohexanone, ethyl acetate.