CN114836993A - Flame-retardant hydrophobic biomass-based waterborne polyurethane coating and preparation method thereof - Google Patents

Abstract

The invention discloses a flame-retardant and hydrophobic biomass-based water-based polyurethane coating and a preparation method thereof. The preparation method comprises the following steps: (1) preparing an isocyanate-terminated polyurethane prepolymer; (2) preparing a biomass-functionalized graphene; ( 3) Preparation of waterborne polyurethane emulsion; (4) adding thickener, leveling agent and defoamer to the waterborne polyurethane emulsion prepared in step (3), and stirring at high speed to obtain a flame retardant and hydrophobic biomass-based waterborne polyurethane coating. The present invention also provides the flame-retardant and hydrophobic biomass-based water-based polyurethane coating prepared by the above method, and the flame-retardant and hydrophobic biomass-based water-based polyurethane coating prepared by the method has good hydrophobicity, flame retardancy and Mechanical properties: After being applied to fabric finishing, the water contact angle of the fabric can reach more than 140°, and the flame retardant grade can reach B2 and above.

Description

A kind of flame-retardant and hydrophobic biomass-based waterborne polyurethane coating and preparation method thereof

technical field

The invention relates to functional materials, in particular to a flame-retardant and hydrophobic biomass-based water-based polyurethane coating and a preparation method thereof.

Background technique

Polyurethane (PU), as one of the six important synthetic materials, has achieved great development in recent years around the world. For many emerging countries, including China, as the wealth of these countries is gradually accumulating and their comprehensive strength is gradually increasing, the demand for polyurethane is also increasing. Moreover, PU materials have excellent comprehensive properties and are used in many fields, especially in furniture, automobile industry, construction, transportation and thermal insulation materials. However, because the oxygen index (OI) of PU is only about 18%, it is a flammable material with a special structure. It burns very fast and has a high flame temperature. When burning, it can release a large amount of toxic gas and smoke that can suffocate and die. , causing great harm to people's lives, property and the environment. Therefore, PU materials must be treated with flame retardant modification to ensure the safety of their use. The flame retardant modification of PU is to overcome the flammability of the material itself to reduce and avoid fire hazards.

Phosphorus-based additive flame retardants mainly include red phosphorus (RP) and ammonium polyphosphate (APP). The effect of suppressing the flame; on the other hand, their condensed phases are thermally decomposed into phosphoric acid substances, which will promote the dehydration and carbonization of the matrix and form a protective carbon layer. Nitrogen-containing flame retardants such as melamine and its derivatives are thermally decomposed to form flame-retardant or non-flammable gases, which have the effect of diluting oxygen and flammable hydrocarbons in the gas phase, thereby achieving the purpose of flame retardant. At present, the phosphorus-nitrogen synergistic flame retardant system mainly uses phosphorus-containing compounds and nitrogen-containing compounds to generate a single-component phosphorus-nitrogen flame retardant through chemical reaction or physical adsorption, so that it has the characteristics of phosphorus-based and nitrogen-based flame retardants at the same time. Flame retardant effect, so as to play a gas-solid dual-phase synergistic flame retardant effect in the polyurethane matrix.

9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) was synthesized by Sanko Chemical Company in 1972. They used a thermal-condensation method to convert o-phenylphenol derivatives. DOPO is prepared by reacting with phosphorus oxychloride under the action of a catalyst. Because DOPO contains a biphenyl ring structure, it has higher thermal and chemical stability than general unringed organophosphates, and exhibits good gas-phase radical flame suppression and condensed-phase catalytic dehydration into char in RPUF. In addition, the DOPO structure contains P-H bonds, which are very active to olefins, epoxy bonds and carbonyl groups, and can react to generate many derivative flame retardants.

As a new type of two-dimensional layered nanomaterials, graphene has also received more and more attention from researchers in terms of polymer flame retardancy. Graphene as a flame retardant additive is a new direction of flame retardant materials research in recent years. Graphene-based materials have excellent thermal conductivity (thermal conductivity of 5.3×103W/(m·K)), electrical conductivity and good gas barrier properties. Therefore, this unique two-dimensional carbon atomic sheet structure can be used as a good flame retardant to improve the flame retardant properties of polymer materials. When the graphene-based polymer flame retardant material encounters high temperature or open fire, from a microscopic point of view, the graphene sheet structure is dense and continuous as a whole, which can prevent oxygen from entering the deep part of the material.

The bond energy of Si-O bond in silicone is high, the volume of siloxane is large, and the cohesive energy density is low. Therefore, silicon-containing polymers have good hydrophobic properties. Silicon-containing polyurethane can be obtained by simple physical blending of polysiloxane and polyurethane. However, due to the large difference in solubility parameters between the two, with severe phase separation and poor mechanical properties, physical modification can be used to obtain silicon-containing polyurethane. Research on silicone polyurethane is rare. Commonly, it is obtained by chemical modification. Chemical modification can use the reactive group in polyurethane and the hydroxyl group in polysiloxane, or the amino group in silane coupling agent to obtain silicon-containing polyurethane, because silicon is on the surface of polyurethane. There is enrichment phenomenon, therefore, all silicon-containing polyurethanes have good hydrophobic properties. Polydimethylsiloxane (PDMS) is an important organosilicon material. The main chain is composed of Si-O bonds and methyl groups are used as side groups. It has the characteristics of low surface energy, high thermal stability and high transparency in the visible light region. .

However, the flame retardant modification of polyurethane in the prior art still has defects, which cannot meet people's needs.

SUMMARY OF THE INVENTION

In view of the deficiencies in the prior art, the purpose of the present invention is to provide a flame-retardant and hydrophobic biomass-based water-based polyurethane coating with good hydrophobicity, flame retardancy and mechanical properties, and a preparation method thereof.

In order to achieve the above object, the present invention adopts the following technical solutions to realize:

A preparation method of a flame-retardant and hydrophobic biomass-based water-based polyurethane coating, the raw materials are weighed in parts by weight, and the method comprises the following steps:

(1) Preparation of isocyanate group-terminated polyurethane prepolymer

Stir and mix 13-30 parts of polyol, 3-6 parts of hydrophilic chain extender and 3-9 parts of hydroxyl-terminated polydimethylsiloxane to obtain an alcohol mixture, and then add 8-16 parts to it. parts of polyisocyanate, stirred at 50 to 90 ° C for 2 to 4 h, and then added 2 to 6 parts of small molecule chain extender and 2 to 10 parts of 9,10-dihydro-9-oxo-10- [N,N-bis-(2-hydroxyethylaminomethyl)]-10-phosphinophenanthrene-10-oxide, stirring at 40-90°C for 1-5h to obtain an isocyanate-terminated polyurethane prepolymer;

(2) Preparation of biomass functionalized graphene

Graphene oxide is prepared by the modified Hummer method. 2-6 parts of phytic acid and 0.2-0.9 parts of graphene oxide are added to 150-300 parts of deionized water and mixed, and reacted at 50-80 ° C for 3-6 h to obtain Phytic acid functionalized graphene oxide solution, then take 0.2-0.9 parts of phytic acid-functionalized graphene oxide solution and 0.1-2 parts of dopamine, add 150-300 parts of deionized water and mix, adjust the pH value to 8-9, The reaction is stirred at 50-80 °C for 8-10 h to obtain an aqueous solution of biomass-functionalized graphene;

(3) Preparation of water-based polyurethane emulsion

Add 2 to 6 parts of amines to the isocyanate group-terminated polyurethane prepolymer prepared in step (1), stir and react at 30 to 60° C. for 0.5 to 2 h to obtain neutralized polyurethane, and then take 0.1 to 2 parts of step (2) ) The prepared biomass-functionalized graphene aqueous solution is ultrasonically dispersed in 60-150 parts of deionized water, and is added to the neutralized polyurethane, stirred and emulsified to obtain an aqueous polyurethane emulsion;

(4) adding a thickener, a leveling agent and a defoamer to the water-based polyurethane emulsion prepared in step (3), and stirring at a high speed for 1-2 hours to obtain a flame-retardant and hydrophobic biomass-based water-based polyurethane coating.

Further, the polyol in the step (1) is polyester polyol, polyether polyol or vegetable oil polyol.

Further, the hydrophilic chain extender in the step (1) is dimethylolpropionic acid, ethylenedihydroxyethanesulfonate or diethanolamine.

Further, the polyisocyanate in the step (1) is isophorone diisocyanate, diphenylmethane diisocyanate or toluene diisocyanate.

Further, the small molecule chain extender in the step (1) is 1,6-hexanediol, 1,4-butanediol, glycerol, ethylenediamine or ethylene glycol amine.

Further, in the step (3), the stirring and emulsification is carried out under the condition of 10-30° C., and the stirring and emulsification time is 1-4 h.

Further, the amines in the step (3) are triethylamine or ethylenediamine.

The present invention also provides a flame-retardant and hydrophobic biomass-based water-based polyurethane coating prepared by the above method. After the flame-retardant and hydrophobic biomass-based water-based polyurethane coating is applied to fabric finishing, the water contact angle of the fabric can reach more than 140° , the flame retardant grade can reach B2 and above.

Compared with the prior art, the present invention has the following technical effects:

(1) Reactive flame retardant polyurethane is that the reactive groups on the flame retardant are connected to the molecular skeleton of the water-based polyurethane through chemical bonds. The resulting emulsion is stable, the amount of flame retardant is small and it is not easy to separate out. In improving the flame retardant of polyurethane It can also improve the mechanical properties of the material. Therefore, reactive flame retardant modification is an important method for synthesizing flame retardant waterborne polyurethane. DOPO derivative flame retardant is a kind of excellent flame retardant, which is easy to be modified into reactive phosphorus-nitrogen flame retardant and grafted onto the molecular chain of polyurethane, so as to improve the flame retardant performance and mechanical properties of polyurethane. The present invention modifies DOPO into reactive phosphorus nitrogen flame retardant 9,10-dihydro-9-oxo-10-[N,N-bis-(2-hydroxyethylaminomethyl)]-10-phosphine phenanthrene-10-oxide, in which -OH can react directly with -NCO group to convert 9,10-dihydro-9-oxo-10-[N,N-bis-(2-hydroxyethylaminomethyl) )]-10-phosphine-10-oxide was introduced into the molecular chain of WPU. The -OH on the used hydrophobic auxiliary PDMS is also grafted to the WPU molecular chain by reacting with -NCO. Therefore, the present invention obtains a water-based polyurethane with good hydrophobicity, flame retardancy and mechanical properties through the method of in-situ polymerization.

(2) Phytic acid-modified graphene oxide can further improve the flame retardancy and thermal stability of graphene oxide. In order to make the surface of modified graphene oxide have reactive groups, the present invention is based on the bionic method of the viscous protein structure secreted by natural mussels, utilizes the strong electrostatic binding between dopamine and phytic acid, and the adsorption of dopamine on any surface. The principle of film formation is to use dopamine to re-modify phytic acid-functionalized graphene oxide to make its surface with active functional groups, improve the dispersibility of modified graphene in polyurethane, and enhance the flame retardancy of polyurethane.

(3) The flame-retardant and hydrophobic biomass-based water-based polyurethane coating prepared by the method of the present invention has good hydrophobicity, flame retardancy and mechanical properties; after being applied to fabric finishing, the water contact angle of the fabric can reach 140 ° above, the flame retardant grade can reach B2 and above. And the water-based polyurethane emulsion prepared in step (3) can be applied to many fields such as leather, textile, coating, etc., and has a relatively wide range of uses in the fields of synthetic leather and leather finishing and fabric finishing.

Description of drawings

Fig. 1 is the effect diagram of the fabric after the flame-retardant and hydrophobic biomass-based water-based polyurethane coating treatment prepared by Example 2 of the present invention and water droplets contacting;

2 is a graph showing the vertical combustion test effect of the fabric treated with the flame-retardant and hydrophobic biomass-based aqueous polyurethane coating prepared in Example 2 of the present invention.

Detailed ways

The specific content of the present invention will be further explained in detail below in conjunction with the embodiments.

Example 1

The present embodiment provides a method for preparing a flame-retardant and hydrophobic biomass-based water-based polyurethane coating, comprising the following steps:

(1) Preparation of isocyanate group-terminated polyurethane prepolymer

Mix 18 parts of polyester polyol, 3 parts of dimethylol propionic acid and 5 parts of hydroxyl-terminated polydimethylsiloxane, and stir for 0.5 h to obtain an alcohol mixture; then add 10 parts of isopropyl alcohol to it. Phorone diisocyanate was stirred at 60°C for 2h, and then 4 parts of 1,4-butanediol and 5 parts of 9,10-dihydro-9-oxo-10-[N,N-bis-diol were added to it -(2-hydroxyethylaminomethyl)]-10-phosphine-10-oxide, stirred at 60 °C for 2 h to obtain an isocyanate group-terminated polyurethane prepolymer;

(2) Preparation of biomass functionalized graphene

First, graphene oxide was prepared by the modified Hummer method, then 2.5 parts of phytic acid and 0.3 parts of graphene oxide were added to 180 parts of deionized water and mixed, and reacted at 50 °C for 3 hours to obtain phytic acid-functionalized graphene oxide Then take 0.3 part of phytic acid functionalized graphene oxide solution and 0.1 part of dopamine into 200 parts of deionized water and mix, and adjust the pH value to 8 by tris-HCl solution and NaOH solution, and stir the reaction at 70 °C 8.5h, the biomass functionalized graphene aqueous solution was obtained;

(3) Preparation of water-based polyurethane emulsion

After the isocyanate group-terminated polyurethane prepolymer prepared in step (1) was cooled to room temperature, 2 parts of triethylamine was added to it, and the reaction was stirred at 30° C. for 0.5 h to obtain neutralized polyurethane; then 0.5 part of step (2) was taken. The prepared biomass-functionalized graphene aqueous solution was ultrasonically dispersed in 60 parts of deionized water, added to the neutralized polyurethane, and stirred at 15 °C for 1 h for emulsification to obtain an aqueous polyurethane emulsion;

(4) Put the water-based polyurethane emulsion prepared in step (3) into a flask, add an appropriate amount of thickener, leveling agent, and defoamer, and stir at high speed for 1 hour to obtain a flame-retardant and hydrophobic biomass-based water-based polyurethane coating.

Example 2

The present embodiment provides a method for preparing a flame-retardant and hydrophobic biomass-based water-based polyurethane coating, comprising the following steps:

(1) Preparation of isocyanate group-terminated polyurethane prepolymer

Mix 21 parts of polyester polyol, 4 parts of dimethylol propionic acid and 6 parts of hydroxyl-terminated polydimethylsiloxane, and stir for 0.6 h to obtain an alcohol mixture; then add 12 parts of isopropyl alcohol to it. Phorone diisocyanate was stirred at 70°C for 2.5h, and then 3 parts of 1,4-butanediol and 6 parts of 9,10-dihydro-9-oxo-10-[N,N- Bis-(2-hydroxyethylaminomethyl)]-10-phosphinophenanthrene-10-oxide, stirred at 70 °C for 2 h to obtain an isocyanate group-terminated polyurethane prepolymer;

(2) Preparation of biomass functionalized graphene

First, graphene oxide was prepared by the modified Hummer method, then 3 parts of phytic acid and 0.3 part of graphene oxide were added to 200 parts of deionized water and mixed, and reacted at 60 °C for 4 h to obtain phytic acid-functionalized graphene oxide Then take 0.3 part of phytic acid functionalized graphene oxide solution and 0.15 part of dopamine into 250 parts of deionized water and mix, and adjust the pH value to 8.5 by tris-HCl solution and NaOH solution, and stir the reaction at 60 °C 9h, the biomass functionalized graphene aqueous solution was obtained;

(3) Preparation of water-based polyurethane emulsion

After the isocyanate group-terminated polyurethane prepolymer prepared in step (1) was cooled to room temperature, 3 parts of triethylamine was added to it, and the reaction was stirred at 35° C. for 1 h to obtain neutralized polyurethane; then 1 part was prepared in step (2). The biomass-functionalized graphene aqueous solution was ultrasonically dispersed in 85 parts of deionized water, added to the neutralized polyurethane, and stirred at 20 °C for 1.5 h for emulsification to obtain an aqueous polyurethane emulsion;

(4) Put the water-based polyurethane emulsion prepared in step (3) into a flask, add an appropriate amount of thickener, leveling agent, and defoamer, and stir at high speed for 1 hour to obtain a flame-retardant and hydrophobic biomass-based water-based polyurethane coating.

Example 3

The present embodiment provides a method for preparing a flame-retardant and hydrophobic biomass-based water-based polyurethane coating, comprising the following steps:

(1) Preparation of isocyanate group-terminated polyurethane prepolymer

Mix 13 parts of polyester polyol, 5 parts of dimethylol propionic acid and 7 parts of hydroxyl terminated polydimethylsiloxane, and stir for 1 hour to obtain an alcohol mixture; then add 15 parts of isophor. Erone diisocyanate, stirred at 85°C for 3h, and then added 4 parts of 1,4-butanediol and 7 parts of 9,10-dihydro-9-oxo-10-[N,N-bis- (2-hydroxyethylaminomethyl)]-10-phosphine-10-oxide, stirred at 60 °C for 2 h to obtain an isocyanate group-terminated polyurethane prepolymer;

(2) Preparation of biomass functionalized graphene

First, graphene oxide was prepared by the modified Hummer method, then 4 parts of phytic acid and 0.5 part of graphene oxide were added to 250 parts of deionized water and mixed, and reacted at 70 °C for 4.5 h to obtain phytic acid-functionalized graphite oxide Then take 0.5 part of phytic acid functionalized graphene oxide solution and 0.2 part of dopamine into 300 parts of deionized water and mix, and adjust the pH value to 9 by tris-HCl solution and NaOH solution, and stir at 65 °C The reaction was carried out for 10h to obtain an aqueous solution of biomass-functionalized graphene;

(3) Preparation of water-based polyurethane emulsion

After the isocyanate group-terminated polyurethane prepolymer prepared in step (1) was cooled to room temperature, 4 parts of triethylamine was added to it, and the reaction was stirred at 40° C. for 1.5 h to obtain neutralized polyurethane; then 1.2 parts of step (2) were taken. The prepared biomass-functionalized graphene aqueous solution was ultrasonically dispersed in 100 parts of deionized water, added to the neutralized polyurethane, and stirred at 25°C for 2 hours for emulsification to obtain an aqueous polyurethane emulsion;

(4) Put the water-based polyurethane emulsion prepared in step (3) into a flask, add an appropriate amount of thickener, leveling agent, and defoamer, and stir at high speed for 2 hours to obtain a flame-retardant and hydrophobic biomass-based water-based polyurethane coating.

The flame-retardant and hydrophobic biomass-based water-based polyurethane coatings prepared in Examples 1-3 were respectively coated on polyester fabrics, then dried at 80 °C, and then baked at 130 °C for 3 min. After cooling to room temperature, the finished fabrics were respectively The fabric is tested for contact angle and vertical combustion. The vertical combustion test is determined according to GB/T5455-1997 "Vertical Method for Determination of Combustion Properties of Textiles". The results are shown in the following table:

Fig. 1 is the effect diagram of the contact between the fabric and water droplets after the flame retardant and hydrophobic biomass-based water-based polyurethane coating prepared in Example 2; it can be seen from the figure that the flame-retardant and hydrophobic biomass-based water-based polyurethane coating prepared in Example 2 is treated. The water contact angle of the treated fabric is 150.6°, indicating that the flame-retardant and hydrophobic biomass-based waterborne polyurethane coating prepared by the present invention has good hydrophobicity.

Fig. 2 is the vertical burning test effect diagram of the fabric treated with the flame-retardant and hydrophobic biomass-based water-based polyurethane coating prepared in Example 2. After the vertical burning test, the afterburning time of the fabric is 5s, and the damage length is 7.9cm, reaching The B1 level standard indicates that the flame-retardant and hydrophobic biomass-based water-based polyurethane coating prepared by the present invention has good flame retardancy.

Example 4

The present embodiment provides a method for preparing a flame-retardant and hydrophobic biomass-based water-based polyurethane coating, comprising the following steps:

(1) Preparation of isocyanate group-terminated polyurethane prepolymer

Mix 30 parts of polyether polyol, 6 parts of dimethylol propionic acid and 3 parts of hydroxyl-terminated polydimethylsiloxane, and stir for 0.5 h to obtain an alcohol mixture; then add 8 parts of dimethylol Phenylmethane diisocyanate, stirred at 50°C for 4h, and then added 2 parts of glycerol and 2 parts of 9,10-dihydro-9-oxo-10-[N,N-bis-(2-hydroxyl ethylaminomethyl)]-10-phosphine-10-oxide, stirred at 40 °C for 5 h to obtain an isocyanate group-terminated polyurethane prepolymer;

(2) Preparation of biomass functionalized graphene

First, graphene oxide was prepared by the modified Hummer method, then 2 parts of phytic acid and 0.9 parts of graphene oxide were added to 300 parts of deionized water and mixed, and reacted at 80 °C for 6 h to obtain phytic acid-functionalized graphene oxide solution, then take 0.2 part of phytic acid functionalized graphene oxide solution and 1 part of dopamine, add 150 parts of deionized water and mix, and pass through tris-HCL solution (0.1mol/L) and NaOH solution (0.1mol/L) The pH value was adjusted to 8, and the reaction was stirred at 50 °C for 8 h to obtain an aqueous solution of biomass-functionalized graphene;

(3) Preparation of water-based polyurethane emulsion

After the isocyanate group-terminated polyurethane prepolymer prepared in step (1) was cooled to room temperature, 6 parts of ethylenediamine was added to it, and the reaction was stirred at 60° C. for 2 hours to obtain neutralized polyurethane; then 0.1 part of step (2) was taken to prepare The biomass-functionalized graphene aqueous solution was ultrasonically dispersed in 120 parts of deionized water, added to the neutralized polyurethane, and stirred at 10 °C for 4 h for emulsification to obtain an aqueous polyurethane emulsion;

(4) Put the water-based polyurethane emulsion prepared in step (3) into a flask, add an appropriate amount of thickener, leveling agent, and defoamer, and stir at high speed for 1 hour to obtain a flame-retardant and hydrophobic biomass-based water-based polyurethane coating.

Example 5

The present embodiment provides a method for preparing a flame-retardant and hydrophobic biomass-based water-based polyurethane coating, comprising the following steps:

(1) Preparation of isocyanate group-terminated polyurethane prepolymer

Mix 15 parts of polyester polyol, 5 parts of diethanolamine and 9 parts of hydroxyl-terminated polydimethylsiloxane, and stir for 0.6 h to obtain an alcohol mixture; then add 16 parts of toluene diisocyanate to it, Stir at 90°C for 2 h, and then add 6 parts of 1,6-hexanediol and 10 parts of 9,10-dihydro-9-oxo-10-[N,N-bis-(2-hydroxyethyl) to it Aminomethyl)]-10-phosphinophenanthrene-10-oxide, stirred at 90 ° C for 1 h to obtain an isocyanate group-terminated polyurethane prepolymer;

(2) Preparation of biomass functionalized graphene

First, graphene oxide was prepared by the modified Hummer method, then 6 parts of phytic acid and 0.2 part of graphene oxide were added to 150 parts of deionized water and mixed, and reacted at 65 °C for 5 h to obtain phytic acid-functionalized graphene oxide solution, then take 0.9 parts of phytic acid functionalized graphene oxide solution and 2 parts of dopamine, add 300 parts of deionized water to mix, adjust the pH value to 9, and stir and react at 80 ° C for 9.5 hours to obtain biomass-functionalized graphite alkene aqueous solution;

(3) Preparation of water-based polyurethane emulsion

After the isocyanate group-terminated polyurethane prepolymer prepared in step (1) was cooled to room temperature, 5 parts of triethylamine was added to it, and the reaction was stirred at 50° C. for 0.5 h to obtain neutralized polyurethane; then 2 parts of step (2) were taken. The prepared biomass-functionalized graphene aqueous solution was ultrasonically dispersed in 150 parts of deionized water, added to the neutralized polyurethane, and stirred at 30° C. for 3 hours for emulsification to obtain an aqueous polyurethane emulsion;

(4) Put the water-based polyurethane emulsion prepared in step (3) into a flask, add an appropriate amount of thickener, leveling agent, and defoamer, and stir at high speed for 2 hours to obtain a flame-retardant and hydrophobic biomass-based water-based polyurethane coating.

Example 6

The present embodiment provides a method for preparing a flame-retardant and hydrophobic biomass-based water-based polyurethane coating, comprising the following steps:

(1) Preparation of isocyanate group-terminated polyurethane prepolymer

Mix 25 parts of vegetable oil polyol, 4 parts of ethylenedihydroxyethane sulfonate and 4 parts of hydroxyl-terminated polydimethylsiloxane, and stir for 0.5h to obtain an alcohol mixture; then add 9 parts of isopropyl alcohol to it. Phorone diisocyanate, stirred at 65°C for 3.5h, and then added 5 parts of ethylene glycol amine and 8 parts of 9,10-dihydro-9-oxo-10-[N,N-bis- (2-hydroxyethylaminomethyl)]-10-phosphine-10-oxide, stirred at 50 °C for 4 h to obtain an isocyanate group-terminated polyurethane prepolymer;

(2) Preparation of biomass functionalized graphene

First, graphene oxide was prepared by the modified Hummer method, then 5 parts of phytic acid and 0.2 part of graphene oxide were added to 160 parts of deionized water and mixed, and reacted at 65 °C for 5 h to obtain phytic acid-functionalized graphene oxide solution, then take 0.6 part of phytic acid functionalized graphene oxide solution and 0.5 part of dopamine, add 200 parts of deionized water to mix, and adjust by tris-HCl (0.1mol/L) and NaOH (0.1mol/L) solution The pH value reached 8.5, and the reaction was stirred at 65 °C for 9 h to obtain an aqueous solution of biomass-functionalized graphene;

(3) Preparation of water-based polyurethane emulsion

After the isocyanate group-terminated polyurethane prepolymer prepared in step (1) was cooled to room temperature, 2.5 parts of ethylenediamine was added to it, and the reaction was stirred at 45° C. for 1.5 h to obtain neutralized polyurethane; then 1.5 parts of step (2) were taken. The prepared biomass-functionalized graphene aqueous solution was ultrasonically dispersed in 110 parts of deionized water, added to the neutralized polyurethane, and stirred at 25°C for 2.5 hours for emulsification to obtain an aqueous polyurethane emulsion;

(4) Put the water-based polyurethane emulsion prepared in step (3) into a flask, add an appropriate amount of thickener, leveling agent, and defoamer, and stir at high speed for 2 hours to obtain a flame-retardant and hydrophobic biomass-based water-based polyurethane coating.

Comparative Example 1

Xu Genhua et al. used poly-1,4-butanediol adipate diol, 2,2-dimethylol, isophorone diisocyanate and organophosphorus flame retardant 10-(2,5-dihydroxyphenyl) )-10-hydrogen-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO-HQ) is a flame-retardant water-based polyurethane prepared from raw materials.

The main difference between it and the present invention is that it uses an organophosphorus flame retardant, DOPO is not modified into a phosphorus-nitrogen flame retardant, and polydimethylsiloxane is omitted in the preparation of water-based polyurethane, and no Dopamine-modified phytic acid-functionalized graphene oxide aqueous solution was added.

Comparative Example 2

Yin Dongxu selected 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO-BQ), polyether polyol N210 and isophorone Organophosphorus waterborne polyurethane emulsion synthesized from diisocyanate (IPDI) as the main raw material.

The main difference from the present invention is that DOPO is not modified into a phosphorus-nitrogen flame retardant, and the dopamine-modified phytic acid-functionalized graphene oxide aqueous solution is not added when preparing the water-based polyurethane.

From the literature provided by Comparative Example 1, it can be seen that in Comparative Example 1, water-based polyurethane was not applied to fabric finishing, and when the amount of flame retardant in Comparative Example 1 reached 8%, WPU had a better flame retardant effect. Example 1 The hydrophobicity of the resulting WPU was not investigated. It can be known from the literature provided by Comparative Example 2 that when the DOPO-BQ content is 20% in Comparative Example 2, the finished fabric reaches the B2 standard, and in Comparative Example 2, the fabric is treated with a water repellent to achieve hydrophobicity. Compared with Comparative Example 1 and Comparative Example 2, the present invention introduces polydimethylsiloxane into the molecular chain of WPU, realizes the hydrophobicity of the finished fabric, introduces reactive phosphorus-nitrogen flame retardant and adds dopamine-modified phytic acid. The functionalized graphene oxide aqueous solution enables the prepared flame retardant and hydrophobic biomass-based water-based polyurethane coating to achieve better flame retardant effect when the addition amount is small, the finishing fabric can reach the B1 standard, and the hydrophobicity can improve the fabric Excellent washability and prolong the service life of flame retardant fabrics.

Claims (8)

1. a preparation method of a fire-retardant and hydrophobic biomass-based water-based polyurethane coating, raw materials are weighed in parts by weight, and are characterized in that, comprise the steps: (1) Preparation of isocyanate group-terminated polyurethane prepolymer Stir and mix 13-30 parts of polyol, 3-6 parts of hydrophilic chain extender and 3-9 parts of hydroxyl-terminated polydimethylsiloxane to obtain an alcohol mixture, and then add 8-16 parts to it. parts of polyisocyanate, stirred at 50 to 90 ° C for 2 to 4 h, and then added 2 to 6 parts of small molecule chain extender and 2 to 10 parts of 9,10-dihydro-9-oxo-10- [N,N-bis-(2-hydroxyethylaminomethyl)]-10-phosphinophenanthrene-10-oxide, stirring at 40-90°C for 1-5h to obtain an isocyanate-terminated polyurethane prepolymer; (2) Preparation of biomass functionalized graphene Graphene oxide is prepared by the modified Hummer method. 2-6 parts of phytic acid and 0.2-0.9 parts of graphene oxide are added to 150-300 parts of deionized water and mixed, and reacted at 50-80 ° C for 3-6 h to obtain Phytic acid functionalized graphene oxide solution, then take 0.2-0.9 parts of phytic acid-functionalized graphene oxide solution and 0.1-2 parts of dopamine, add 150-300 parts of deionized water and mix, adjust the pH value to 8-9, The reaction is stirred at 50-80 °C for 8-10 h to obtain an aqueous solution of biomass-functionalized graphene; (3) Preparation of water-based polyurethane emulsion Add 2 to 6 parts of amines to the isocyanate group-terminated polyurethane prepolymer prepared in step (1), stir and react at 30 to 60° C. for 0.5 to 2 h to obtain neutralized polyurethane, and then take 0.1 to 2 parts of step (2) ) The prepared biomass-functionalized graphene aqueous solution is ultrasonically dispersed in 60-150 parts of deionized water, and is added to the neutralized polyurethane, stirred and emulsified to obtain an aqueous polyurethane emulsion; (4) adding a thickener, a leveling agent and a defoamer to the water-based polyurethane emulsion prepared in step (3), and stirring at a high speed for 1-2 hours to obtain a flame-retardant and hydrophobic biomass-based water-based polyurethane coating. 2. the preparation method of the fire-retardant and hydrophobic biomass-based waterborne polyurethane coating as claimed in claim 1, is characterized in that, the polyol in described step (1) is polyester polyol, polyether polyol or vegetable oil polyol alcohol. 3. the preparation method of the fire-retardant and hydrophobic biomass-based water-based polyurethane coating as claimed in claim 1, is characterized in that, the hydrophilic chain extender in described step (1) is dimethylol propionic acid, ethyl acetate Dihydroxyethanesulfonate or diethanolamine. 4. the preparation method of flame-retardant and hydrophobic biomass-based water-based polyurethane coating as claimed in claim 1, is characterized in that, the polyisocyanate in described step (1) is isophorone diisocyanate, diphenylmethane diisocyanate Isocyanate or toluene diisocyanate. 5. The preparation method of flame-retardant and hydrophobic biomass-based water-based polyurethane coating as claimed in claim 1, wherein the small molecule chain extender in the step (1) is 1,6-hexanediol, 1 , 4-Butanediol, glycerol, ethylenediamine or ethylene glycol amine. 6. The preparation method of flame-retardant and hydrophobic biomass-based water-based polyurethane coating as claimed in claim 1, characterized in that, in the step (3), the stirring and emulsification is carried out under the condition of 10-30°C, and the stirring and emulsification time is 1 ~4h. 7 . The method for preparing a flame retardant and hydrophobic biomass-based waterborne polyurethane coating according to claim 1 , wherein the amines in the step (3) are triethylamine or ethylenediamine. 8 . 8. A flame-retardant and hydrophobic biomass-based water-based polyurethane coating prepared by the method of claim 1, wherein the flame-retardant and hydrophobic biomass-based water-based polyurethane coating is applied to fabric finishing, and the water contact of the fabric The angle can reach more than 140°, and the flame retardant grade can reach B2 and above.

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