阅读说明：本技术 一种水性自修复木器漆及其制备方法 (Water-based self-repairing wood paint and preparation method thereof ) 是由 佘学彬 殷玉花 欧阳倩雯 杨亮庆 吕奇洪 陈浩 于 2021-09-15 设计创作，主要内容包括：本发明公开了一种水性自修复木器漆及其制备方法,本发明涉及涂料技术领域。所述水性自修复木器漆按照重量份计包括：改性水性聚氨酯乳液60～70份、水性丙烯酸乳液10～20份、消泡剂0.1～0.3份、润湿剂0.2～0.3份、蜡粉1～2份、成膜助剂3～5份、水3～5份、增稠剂0.1～0.2份；所述改性水性聚氨酯乳液为改性氧化石墨烯改性水性聚氨酯乳液,所述改性氧化石墨烯为聚二甲基硅氧烷修饰氧化石墨烯。相应地,本发明还提供了一种水性自修复木器漆的制备方法。本发明提供的水性自修复木器漆具有高机械性能和良好的抗刮伤以及自修复能力。(The invention discloses a water-based self-repairing wood paint and a preparation method thereof, and relates to the technical field of coatings. The waterborne self-repairing wood lacquer comprises the following components in parts by weight: 60-70 parts of modified waterborne polyurethane emulsion, 10-20 parts of waterborne acrylic emulsion, 0.1-0.3 part of defoaming agent, 0.2-0.3 part of wetting agent, 1-2 parts of wax powder, 3-5 parts of film-forming assistant, 3-5 parts of water and 0.1-0.2 part of thickening agent; the modified aqueous polyurethane emulsion is modified graphene oxide modified aqueous polyurethane emulsion, and the modified graphene oxide is polydimethylsiloxane modified graphene oxide. Correspondingly, the invention also provides a preparation method of the water-based self-repairing wood lacquer. The waterborne self-repairing wood lacquer provided by the invention has high mechanical property and good scratch resistance and self-repairing capability.)

1. The water-based self-repairing wood lacquer is characterized by comprising the following components in parts by weight:

60-70 parts of modified waterborne polyurethane emulsion, 10-20 parts of waterborne acrylic emulsion, 0.1-0.3 part of defoaming agent, 0.2-0.3 part of wetting agent, 1-2 parts of wax powder, 3-5 parts of film-forming assistant, 3-5 parts of water and 0.1-0.2 part of thickening agent;

the modified aqueous polyurethane emulsion is modified graphene oxide modified aqueous polyurethane emulsion, and the modified graphene oxide is polydimethylsiloxane modified graphene oxide.

2. The aqueous self-repairing wood lacquer according to claim 1, wherein the polydimethylsiloxane-modified graphene oxide is prepared by the following method:

(1) mixing polydimethylsiloxane, n-heptane and tetraethyl orthosilicate, dropwise adding dibutyltin dilaurate, stirring for reaction, and drying;

(2) mixing graphene oxide and hydrazine hydrate for reaction, and washing and drying after the reaction is finished;

(3) and (3) mixing the graphene oxide obtained in the step (2) with the polydimethylsiloxane obtained in the step (1), and keeping the temperature at 300-400 ℃ for 3-5 h to obtain the polydimethylsiloxane modified graphene oxide.

3. The waterborne self-repairing wood lacquer according to claim 2, wherein in the step (1), the addition amount of the tetraethyl orthosilicate is 5-20% of that of the polydimethylsiloxane; the adding amount of the n-heptane is 3-5 times of that of the polydimethylsiloxane;

in the step (2), the mass concentration of the graphene oxide in hydrazine hydrate is 10-50 g/L;

in the step (3), the adding weight ratio of the graphene oxide obtained in the step (2) to the polydimethylsiloxane obtained in the step (1) is (4-8): (1-3).

4. The aqueous self-repairing wood lacquer according to claim 2, wherein the preparation method of the modified aqueous polyurethane emulsion comprises the following steps:

(i) reacting polytetrahydrofuran ether glycol, isophorone diisocyanate and a catalyst at 60-80 ℃ for 2-4 h to obtain a prepolymer;

(ii) mixing 2, 2-hydroxymethylpropionic acid and polydimethylsiloxane modified graphene oxide with the prepolymer, and reacting for 4-6 h at the temperature of 60-80 ℃;

(iii) and (3) adding 1, 4-butanediol into the reaction system in the step (ii), cooling to 20-40 ℃, and adding triethylamine and water to obtain the modified waterborne polyurethane emulsion.

5. The waterborne self-repairing wood lacquer according to claim 4, wherein in the step (i), 15-30 parts of polytetrahydrofuran ether glycol is stirred and heated to 60-80 ℃, 5-15 parts of isophorone diisocyanate and a catalyst are added, and a prepolymer is obtained after reaction for 2-4 hours;

in the step (ii), 1-5 parts of 2, 2-hydroxymethylpropionic acid and 0.04-0.2 part of polydimethylsiloxane modified graphene oxide are mixed and added into the prepolymer obtained in the step (i) to react for 4-6 hours at the temperature of 60-80 ℃;

in the step (iii), 0.1-2 parts of 1, 4-butanediol is added into the reaction system in the step (ii), the temperature is reduced to 20-40 ℃, 1-10 parts of triethylamine and 50-70 parts of water are added, and then the mixture is dispersed, so that the polydimethylsiloxane modified graphene oxide modified waterborne polyurethane emulsion is obtained.

6. The waterborne self-repairing wood lacquer according to claim 5, wherein in the step (ii), the addition amount of the polydimethylsiloxane-modified graphene oxide is 0.04-0.12 parts.

7. The waterborne self-repairing wood paint of claim 1, wherein the solid content of the modified waterborne polyurethane emulsion is 35-45%, and the pH value is 7-9;

the solid content of the water-based acrylic emulsion is 35-45%, and the pH value is 7-9.

8. The aqueous wood self-healing paint of claim 1,

the defoaming agent is polyether defoaming agent or modified organic silicon;

the wetting agent is a polyether modified water-based wetting agent or an organic silicon modified water-based wetting agent;

the film forming auxiliary agent is one or more of propylene glycol, DPM and DPNB;

the thickening agent is a polyurethane associative thickening agent;

the wax powder is one or more of Fischer-Tropsch wax, polypropylene wax and polyolefin wax.

9. The preparation method of the water-based self-repairing wood lacquer is used for preparing the water-based self-repairing wood lacquer as claimed in any one of claims 1 to 8, and comprises the following steps:

preparing modified graphene oxide;

(II) preparing a modified aqueous polyurethane emulsion by using the modified graphene oxide as a raw material;

and (III) mixing and stirring the modified waterborne polyurethane emulsion, the waterborne acrylic emulsion, the defoaming agent, the wetting agent, the wax powder, the film-forming assistant, water, the defoaming agent and the thickening agent to obtain a finished product.

10. The method for preparing the aqueous self-repairing wood lacquer according to claim 9, wherein the step (three) comprises the following steps:

a, adding the modified waterborne polyurethane emulsion and the waterborne acrylic emulsion in proportion, stirring for 3-8 min at a rotating speed of 800-1100 r/min, adding the defoaming agent, stirring for 3-8 min at a rotating speed of 1100-1300 r/min, adding the wetting agent and the dispersing agent respectively, stirring for 3-8 min at a rotating speed of 1300-1500 r/min, adding the wax powder after the stirring speed is reduced to 500-700 r/min, stirring for 3-8 min, and then accelerating to 1500-1700 r/min, and stirring for 15-25 min to obtain a first slurry;

b, mixing the film-forming assistant and water according to the ratio of (1-2): (1-2) mixing the components in a mass ratio to obtain a first mixed solution; adding the first mixed solution into the first slurry, stirring at the rotating speed of 1100-1300 r/min for 15-20 min, reducing the stirring speed to 900-1000 r/min, adding the thickening agent, and stirring for 5-10 min to obtain a second slurry;

c, adjusting the viscosity of the second slurry to 60-70 s, standing for 0.5-1.5 h, and filtering to obtain a finished product.

Technical Field

The invention relates to the technical field of coatings, in particular to a water-based self-repairing wood lacquer and a preparation method thereof.

Background

The development and production of water-based paint have been in China for more than 20 years, a lot of experience is accumulated in the period, the paint industry is gradually shifted from traditional varieties which are high in pollution and energy consumption and extremely depend on products in the petroleum industry to water-based paint products which are environment-friendly and energy-saving products, and the field of wood products needs to be environment-friendly, safe and certain functionality due to the use purpose and the consumer demand. The water paint film is often scratched and bruised in the using process, cracks appear, and the decorative effect, the functionality and the service life of the paint are influenced.

Disclosure of Invention

The invention aims to solve the technical problem of providing the water-based self-repairing wood lacquer which has high mechanical property and good scratch resistance and self-repairing capability.

The technical problem to be solved by the invention is to provide a preparation method of the water-based self-repairing wood lacquer, the method has stable process, and the obtained water-based self-repairing wood lacquer has a self-repairing function.

In order to solve the technical problems, the invention provides a water-based self-repairing wood lacquer which comprises the following components in parts by weight:

60-70 parts of modified waterborne polyurethane emulsion, 10-20 parts of waterborne acrylic emulsion, 0.1-0.3 part of defoaming agent, 0.2-0.3 part of wetting agent, 1-2 parts of wax powder, 3-5 parts of film-forming assistant, 3-5 parts of water and 0.1-0.2 part of thickening agent;

the modified aqueous polyurethane emulsion is modified graphene oxide modified aqueous polyurethane emulsion, and the modified graphene oxide is polydimethylsiloxane modified graphene oxide.

Preferably, the polydimethylsiloxane modified graphene oxide is prepared by the following method:

(1) mixing polydimethylsiloxane, n-heptane and tetraethyl orthosilicate, dropwise adding dibutyltin dilaurate, stirring for reaction, and drying;

(2) mixing graphene oxide and hydrazine hydrate for reaction, and washing and drying after the reaction is finished;

(3) and (3) mixing the graphene oxide obtained in the step (2) with the polydimethylsiloxane obtained in the step (1), and keeping the temperature at 300-400 ℃ for 3-5 h to obtain the polydimethylsiloxane modified graphene oxide.

Preferably, in the step (1), the addition amount of the tetraethyl orthosilicate is 5-20% of that of the polydimethylsiloxane; the adding amount of the n-heptane is 3-5 times of that of the polydimethylsiloxane;

in the step (2), the mass concentration of the graphene oxide in hydrazine hydrate is 10-50 g/L;

in the step (3), the adding weight ratio of the graphene oxide obtained in the step (2) to the polydimethylsiloxane obtained in the step (1) is (4-8): (1-3).

Preferably, the preparation method of the modified aqueous polyurethane emulsion comprises the following steps:

(i) reacting polytetrahydrofuran ether glycol, isophorone diisocyanate and a catalyst at 60-80 ℃ for 2-4 h to obtain a prepolymer;

(ii) mixing 2, 2-hydroxymethylpropionic acid and polydimethylsiloxane modified graphene oxide with the prepolymer, and reacting for 4-6 h at the temperature of 60-80 ℃;

(iii) and (3) adding 1, 4-butanediol into the reaction system in the step (ii), cooling to 20-40 ℃, and adding triethylamine and water to obtain the modified waterborne polyurethane emulsion.

Preferably, in the step (i), 15-30 parts of polytetrahydrofuran ether glycol is stirred and heated to 60-80 ℃, 5-15 parts of isophorone diisocyanate and a catalyst are added, and a prepolymer is obtained after reaction for 2-4 hours;

in the step (ii), 1-5 parts of 2, 2-hydroxymethylpropionic acid and 0.04-0.2 part of polydimethylsiloxane modified graphene oxide are mixed and added into the prepolymer obtained in the step (i) to react for 4-6 hours at the temperature of 60-80 ℃;

in the step (iii), 0.1-2 parts of 1, 4-butanediol is added into the reaction system in the step (ii), the temperature is reduced to 20-40 ℃, 1-10 parts of triethylamine and 50-70 parts of water are added, and then the mixture is dispersed, so that the polydimethylsiloxane modified graphene oxide modified waterborne polyurethane emulsion is obtained.

Preferably, in the step (ii), the addition amount of the polydimethylsiloxane modified graphene oxide is 0.04-0.12 part.

Preferably, the solid content of the modified waterborne polyurethane emulsion is 35-45%, and the pH value is 7-9;

the solid content of the water-based acrylic emulsion is 35-45%, and the pH value is 7-9.

Preferably, the defoaming agent is polyether defoaming agent or modified organic silicon;

the wetting agent is a polyether modified water-based wetting agent or an organic silicon modified water-based wetting agent;

the film forming auxiliary agent is one or more of propylene glycol, DPM and DPNB;

the thickening agent is a polyurethane associative thickening agent;

the wax powder is one or more of Fischer-Tropsch wax, polypropylene wax and polyolefin wax.

The invention also provides a preparation method of the waterborne self-repairing wood lacquer, which comprises the following steps:

preparing modified graphene oxide;

(II) preparing a modified aqueous polyurethane emulsion by using the modified graphene oxide as a raw material;

and (III) mixing and stirring the modified waterborne polyurethane emulsion, the waterborne acrylic emulsion, the defoaming agent, the wetting agent, the wax powder, the film-forming assistant, water, the defoaming agent and the thickening agent to obtain a finished product.

Preferably, the step (three) includes the steps of:

a, adding the modified waterborne polyurethane emulsion and the waterborne acrylic emulsion in proportion, stirring for 3-8 min at a rotating speed of 800-1100 r/min, adding the defoaming agent, stirring for 3-8 min at a rotating speed of 1100-1300 r/min, adding the wetting agent and the dispersing agent respectively, stirring for 3-8 min at a rotating speed of 1300-1500 r/min, adding the wax powder after the stirring speed is reduced to 500-700 r/min, stirring for 3-8 min, and then accelerating to 1500-1700 r/min, and stirring for 15-25 min to obtain a first slurry;

b, mixing the film-forming assistant and water according to the ratio of (1-2): (1-2) mixing the components in a mass ratio to obtain a first mixed solution; adding the first mixed solution into the first slurry, stirring at the rotating speed of 1100-1300 r/min for 15-20 min, reducing the stirring speed to 900-1000 r/min, adding the thickening agent, and stirring for 5-10 min to obtain a second slurry;

c, adjusting the viscosity of the second slurry to 60-70 s, standing for 0.5-1.5 h, and filtering to obtain a finished product.

The implementation of the invention has the following beneficial effects:

1. the waterborne self-repairing wood lacquer provided by the invention comprises a modified waterborne polyurethane emulsion, wherein the modified waterborne polyurethane emulsion is a modified graphene oxide modified waterborne polyurethane emulsion, and the modified graphene oxide is polydimethylsiloxane modified graphene oxide. The addition of graphene oxide to the polyurethane structure may improve the mechanical stability, chemical resistance and film-forming toughness of the polyurethane system. Furthermore, the polydimethylsiloxane modified graphene oxide modified aqueous polyurethane emulsion is beneficial to improving the mechanical property of the aqueous polyurethane emulsion, so that the scratch resistance and self-repairing capability of a paint film of the aqueous wood lacquer are improved.

2. The preparation method of the waterborne self-repairing wood lacquer provided by the invention comprises three steps of self-preparing modified graphene oxide, self-preparing modified waterborne polyurethane and preparing the waterborne self-repairing wood lacquer.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below.

The invention provides a water-based self-repairing wood lacquer, which comprises the following components in parts by weight:

60-70 parts of modified waterborne polyurethane emulsion, 10-20 parts of waterborne acrylic emulsion, 0.1-0.3 part of defoaming agent, 0.2-0.3 part of wetting agent, 1-2 parts of wax powder, 3-5 parts of film-forming assistant, 3-5 parts of water and 0.1-0.2 part of thickening agent;

the modified aqueous polyurethane emulsion is modified graphene oxide modified aqueous polyurethane emulsion, and the modified graphene oxide is polydimethylsiloxane modified graphene oxide.

The waterborne self-repairing wood lacquer provided by the invention comprises a modified waterborne polyurethane emulsion, wherein the modified waterborne polyurethane emulsion is a modified graphene oxide modified waterborne polyurethane emulsion, and the modified graphene oxide is polydimethylsiloxane modified graphene oxide. The addition of graphene oxide to the polyurethane structure may improve the mechanical stability, chemical resistance and film-forming toughness of the polyurethane system. Furthermore, the polydimethylsiloxane modified graphene oxide modified aqueous polyurethane emulsion is beneficial to improving the mechanical property of the aqueous polyurethane emulsion, so that the scratch resistance and self-repairing capability of a paint film of the aqueous wood lacquer are improved.

Preferably, the polydimethylsiloxane modified graphene oxide is prepared by the following method:

(1) mixing polydimethylsiloxane, n-heptane and tetraethyl orthosilicate, dropwise adding dibutyltin dilaurate, stirring for reaction, and drying;

(2) mixing graphene oxide and hydrazine hydrate for reaction, and washing and drying after the reaction is finished;

(3) and (3) mixing the graphene oxide obtained in the step (2) with the polydimethylsiloxane obtained in the step (1), and keeping the temperature at 300-400 ℃ for 3-5 h to obtain the polydimethylsiloxane modified graphene oxide.

More preferably, in the step (1), the addition amount of the tetraethyl orthosilicate is 5-20% of that of the polydimethylsiloxane; the adding amount of the n-heptane is 3-5 times of that of the polydimethylsiloxane;

in the step (2), the mass concentration of the graphene oxide in hydrazine hydrate is 10-50 g/L;

in the step (3), the adding ratio of the graphene oxide obtained in the step (2) to the polydimethylsiloxane obtained in the step (1) is (4-8): (1-3).

It should be noted that in the preparation method of the modified graphene oxide provided by the invention, firstly, polydimethylsiloxane is subjected to crosslinking modification in the step (1), compared with the case that polydimethylsiloxane and graphene oxide are directly added and mixed, the graphene oxide is modified by the crosslinked polydimethylsiloxane, the obtained polydimethylsiloxane-modified graphene oxide can be better matched with the aqueous polyurethane emulsion, and the obtained aqueous self-repairing wood lacquer has stronger cohesion and compactness. In addition, after the graphene oxide is reduced by hydrazine hydrate according to the preparation process, carboxyl and carbonyl on the surface of the graphene oxide disappear, and polydimethylsiloxane serving as a substance with low surface free energy is heated, decomposed and deposited on the surface of the graphene oxide under the high-temperature condition to obtain the polydimethylsiloxane modified graphene oxide.

Preferably, in the step (2), graphene oxide and hydrazine hydrate are mixed and reacted, and the reaction temperature is 80-110 ℃.

After obtaining the polydimethylsiloxane modified graphene oxide, modifying the waterborne polyurethane by using the polydimethylsiloxane modified graphene oxide, preferably, the preparation method of the modified waterborne polyurethane emulsion comprises the following steps:

(i) reacting polytetrahydrofuran ether glycol, isophorone diisocyanate and a catalyst at 60-80 ℃ for 2-4 h to obtain a prepolymer;

(ii) mixing 2, 2-hydroxymethylpropionic acid and polydimethylsiloxane modified graphene oxide with the prepolymer, and reacting for 4-6 h at the temperature of 60-80 ℃;

(iii) and (3) adding 1, 4-butanediol into the reaction system in the step (ii), cooling to 20-40 ℃, and adding triethylamine and water to obtain the modified waterborne polyurethane emulsion.

Preferably, in the step (i), 15-30 parts of polytetrahydrofuran ether glycol is stirred and heated to 60-80 ℃, 5-15 parts of isophorone diisocyanate and a catalyst are added, and a prepolymer is obtained after reaction for 2-4 hours;

in the step (ii), 1-5 parts of 2, 2-hydroxymethylpropionic acid and 0.04-0.2 part of polydimethylsiloxane modified graphene oxide are mixed and added into the prepolymer obtained in the step (i) to react for 4-6 hours at the temperature of 60-80 ℃;

in the step (iii), 0.1-2 parts of 1, 4-butanediol is added into the reaction system in the step (ii), the temperature is reduced to 20-40 ℃, 1-10 parts of triethylamine and 50-70 parts of water are added, and then the mixture is dispersed, so that the polydimethylsiloxane modified graphene oxide modified waterborne polyurethane emulsion is obtained.

Most preferably, in the step (ii), the addition amount of the polydimethylsiloxane modified graphene oxide is 0.04-0.12 g.

It should be noted that the oxygen-containing functional group on the surface of the polydimethylsiloxane-modified graphene oxide fills the gap between the paint film and the cross-linked carbamate, so as to form a network structure, so that the paint film has stronger cohesion and tightness, and the tensile strength and elongation at break of the modified waterborne polyurethane are improved. The addition amount of the polydimethylsiloxane modified graphene oxide has an important influence on the performance of the obtained modified waterborne polyurethane, and the inventor finds that the tensile strength and the elongation at break of the obtained modified waterborne polyurethane show a trend that the tensile strength and the elongation at break gradually increase and then become stable along with the increase of the addition amount of the polydimethylsiloxane modified graphene oxide.

Moreover, the structure of the molecular chain of the waterborne polyurethane is influenced to a certain extent by adding the polydimethylsiloxane modified graphene oxide, so that more energy is needed for breaking the urethane bond, and meanwhile, the thermal decomposition of the polydimethylsiloxane modified graphene oxide and the urethane group is inhibited to a certain extent by the hydrogen bond existing between the polydimethylsiloxane modified graphene oxide and the urethane group, so that the performance of the whole paint film is improved. However, when the addition amount of the polydimethylsiloxane-modified graphene oxide exceeds a certain range, the performance of the whole paint film is not improved mechanically any more, but tends to be stable, so that the addition amount of the polydimethylsiloxane-modified graphene oxide needs to be controlled.

In addition, the solid content of the modified aqueous polyurethane emulsion and the solid content of the aqueous acrylic emulsion influence the film forming speed and the film performance of the finally obtained aqueous self-repairing wood lacquer, the film forming speed of the aqueous self-repairing wood lacquer is reduced due to the fact that the solid content of the modified aqueous polyurethane emulsion and the solid content of the aqueous acrylic emulsion are low, otherwise, the tensile strength of the material is reduced due to the fact that the solid content of the modified aqueous polyurethane emulsion and the solid content of the aqueous acrylic emulsion are too high, and the self-repairing capability of the film is influenced to a certain extent, so that preferably, the solid content of the modified aqueous polyurethane emulsion is 35-45%, and the pH value is 7-9; the solid content of the water-based acrylic emulsion is 35-45%, and the pH value is 7-9. More preferably, the solid content of the modified waterborne polyurethane emulsion is 40%, and the pH value is 8.2; the solid content of the water-based acrylic emulsion is 40%, and the pH value is 8.

In addition, the waterborne self-repairing wood lacquer also comprises a plurality of auxiliary agents, and specifically, the defoaming agent is a polyether defoaming agent or modified organic silicon; preferably, the antifoaming agent is one or more of BYK-024, tego810, and tego 825. The defoaming agent can solve the problem of bubbles in the process of paint preparation and construction, and ensures that a paint film has a complete surface effect. Preferably, the weight part of the defoaming agent is 0.2-0.3 part.

The wetting agent is a polyether modified water-based wetting agent or an organic silicon modified water-based wetting agent; preferably, the wetting agent is tego4100 or BYK-364. The wetting agent can reduce the surface tension of wood, improve the fluidity of the water paint and increase the contact area. Preferably, the wetting agent is present in an amount of 0.3 parts by weight.

Preferably, the coalescent is one or more of propylene glycol, DPM and DPNB. The obtained film-forming assistant can reduce the lowest film-forming temperature of a paint film and achieve the balance of high performance and low-temperature construction. Preferably, the film forming aid is present in 4 parts by weight.

The thickening agent is of polyurethane association type; preferably, the thickener is one or more of PUR44, PUR40, PUR64, PUR80 and PUR 85. The thickener can adjust rheological property to meet the requirements of the coating in the processes of production, storage, construction and film forming. Preferably, the weight part of the thickening agent is 0.15-0.2 part.

The wax powder is one or more of Fischer-Tropsch wax, polypropylene wax and polyolefin wax; preferably, the wax powder is one or more of a mixture of a sand rope W605G, a gelatin MXF9510D and a gelatin MXS 3815. The wax powder has the functions of abrasion resistance, scraping resistance and adhesion resistance, and can improve the waterproof and scraping resistance of the water-based paint. Preferably, the wax powder accounts for 1.5-2 parts by weight.

Besides the above-mentioned additives, the waterborne self-repairing wood lacquer also includes a dispersant, a leveling agent, a PH regulator and a matting agent, which are not limited to the above list.

Preferably, the dispersant is anionic or/and nonionic, more preferably, the dispersant is tego755w and/or tego 3800. The dispersant acts during the stabilization of the dispersion of the pigment, bringing the dispersion to a stable state. Preferably, the weight part of the dispersant is 0.1-0.5 part.

Preferably, the leveling agent is an organic silicon copolymer, and more preferably, the leveling agent is tego 450. The leveling agent can help the wet film to fully wet the substrate and uniformly spread, reduce the surface tension gradient generated by the wet film, shorten the time of surface flow and up-down convection, enable the surface of the coating film to reach uniform surface tension as soon as possible, and obtain a smooth coating film. Preferably, the weight part of the leveling agent is 0.1-0.5 part.

Preferably, the pH regulator is an ammonia pH regulator, and more preferably, the pH regulator is AMP-95. The pH regulator can regulate the pH value of the water-based paint so as to ensure the storage stability, viscosity and performance of the water-based paint. Preferably, the weight part of the pH regulator is 0.1-2 parts.

Preferably, the matting powder is silicon dioxide, and more preferably, the matting powder is one or more of graves 7000, graves 907 and graves 800. The matting powder can obviously reduce the surface gloss of a coating, and preferably, the matting powder accounts for 0.1-0.3 part by weight.

In conclusion, the waterborne self-repairing wood paint with high mechanical strength is obtained by adopting the specific paint formula and the specific modification method, and the paint film of the waterborne self-repairing wood paint has high tensile strength and elongation at break, can have strong shrinkage recovery capability, and can have certain self-healing capability after being damaged for a period of time.

In order to achieve better self-repairing capability of a paint film, the invention also provides a preparation method of the water-based self-repairing wood paint, which specifically comprises the following steps:

preparing modified graphene oxide;

(II) preparing a modified aqueous polyurethane emulsion by using the modified graphene oxide as a raw material;

and (III) mixing and stirring the modified waterborne polyurethane emulsion, the waterborne acrylic emulsion, the defoaming agent, the wetting agent, the wax powder, the film-forming assistant, water, the defoaming agent and the thickening agent to obtain a finished product.

In the preparation method provided by the invention, graphene oxide is modified to obtain polydimethylsiloxane modified graphene oxide. And modifying the graphene oxide modified by polydimethylsiloxane to obtain the modified aqueous polyurethane emulsion. And finally, mixing the modified waterborne polyurethane emulsion with other raw materials of the waterborne self-repairing wood paint to obtain a finished product. The graphene oxide has excellent mechanical strength, larger surface area and easy chemical modification performance, is an oxygen-rich carbonaceous layered material, has carboxyl, carbonyl, hydroxyl and epoxy functional groups on a basal plane, can be used for chemical modification of organic polymers, and is easy to form organic-inorganic chemical hybrids. The polydimethylsiloxane has the characteristics of high surface hydrophobicity, low density, strong biocompatibility and various porous structures, and is a high-elasticity polymer material. Graphene oxide when added to a polyurethane structure can improve the mechanical stability, chemical resistance and toughness of the polyurethane system. Furthermore, polydimethylsiloxane modified graphene oxide is added into polyurethane to modify the polyurethane, so that the mechanical property of the resin can be effectively improved, and the scratch resistance and self-repairing capability of a paint film are improved.

Next, each step of the preparation method will be described in detail as follows.

The step (I) and the step (II) are described above, and are not repeated here.

And (3) mixing and stirring the modified waterborne polyurethane emulsion, the waterborne acrylic emulsion, the defoaming agent, the wetting agent, the wax powder, the film-forming assistant, the water, the defoaming agent and the thickening agent to obtain a finished product.

Preferably, the paint comprises the following components in parts by weight: 60-70 parts of modified waterborne polyurethane emulsion, 10-20 parts of waterborne acrylic emulsion, 0.1-0.3 part of defoaming agent, 0.2-0.3 part of wetting agent, 1-2 parts of wax powder, 3-5 parts of film-forming assistant, 3-5 parts of water and 0.1-0.2 part of thickening agent.

In step (iii), a dispersant, a leveling agent, a PH adjuster, and a matting agent may be further included, but not limited to the above. The above description of the raw materials involved in step (III) may be referred to.

Preferably, the preparation method of the step (three) comprises the following steps:

a, adding the modified waterborne polyurethane emulsion and the waterborne acrylic emulsion in proportion, stirring for 3-8 min at a rotating speed of 800-1100 r/min, sequentially adding the defoaming agent, stirring for 3-8 min at a rotating speed of 1100-1300 r/min, respectively adding the wetting agent and the dispersing agent, stirring for 3-8 min at a rotating speed of 1300-1500 r/min, adding the wax powder after the stirring speed is reduced to 500-700 r/min, stirring for 3-8 min, and then accelerating to 1500-1700 r/min, and stirring for 15-25 min to obtain a first slurry;

b, mixing the film-forming assistant and water according to the ratio of (1-2): (1-2) mixing the components in a mass ratio to obtain a first mixed solution; adding the first mixed solution into the first slurry, stirring at the rotating speed of 1100-1300 r/min for 15-20 min, reducing the stirring speed to 900-1000 r/min, adding the thickening agent, and stirring for 5-10 min to obtain a second slurry;

c, adjusting the viscosity of the second slurry to 60-70 s, standing for 0.5-1.5 h, and filtering to obtain a finished product.

More preferably, the preparation method of the step (three) comprises the following steps:

a. adding the modified waterborne polyurethane emulsion and the waterborne acrylic emulsion in proportion, stirring for 5min at the rotating speed of 1000r/min, sequentially adding the defoaming agent, stirring for 5min at the rotating speed of 1200r/min, respectively adding the wetting agent and the dispersing agent, stirring for 5min at the rotating speed of 1400r/min, reducing the stirring speed to 600r/min, adding the wax powder, stirring for 5min, and accelerating to 1600r/min, and stirring for 20min to obtain a first slurry;

b. mixing the film-forming assistant and water according to the ratio of 1: 1 to obtain a first mixed solution; adding the first mixed solution into the first slurry, stirring for 15min at the rotating speed of 1200r/min, reducing the stirring speed to 1000r/min, adding the thickening agent, and stirring for 8min to obtain second slurry;

c. and adjusting the viscosity of the second slurry to 65s, standing for 1h, and filtering to obtain a finished product.

Preferably, in the step c, the water-based self-repairing wood paint is filtered for 1-2 times by using a 150-250 mesh filter screen and then filtered for 1-2 times by using a 200-300 mesh filter screen, so that the fineness of the water-based self-repairing wood paint is less than 25 micrometers.

It should be noted that the present invention adds the additives separately according to their characteristics and applies specific stirring conditions to enable all the raw materials to be mixed well and stably and to exert their functional effects to the maximum extent. If a one-pot porridge type mixing method is adopted, the obtained waterborne self-repairing wood lacquer has poor compactness and low cohesion.

In conclusion, the aqueous self-repairing wood lacquer prepared by the preparation method shows high stability and storage capacity (the wood lacquer is stored for 6 months at room temperature without any deterioration of physical or chemical properties), and has an excellent post-injury self-repairing function.

The invention is further illustrated by the following specific examples:

example 1

The water-based self-repairing wood lacquer comprises the following components in parts by weight:

65 parts of modified waterborne polyurethane emulsion, 15 parts of waterborne acrylic emulsion, 0.2 part of defoaming agent, 0.2 part of wetting agent, 2 parts of wax powder, 4 parts of film-forming assistant, 4 parts of water and 0.1 part of thickening agent;

the modified aqueous polyurethane emulsion is modified graphene oxide modified aqueous polyurethane emulsion, and the modified graphene oxide is polydimethylsiloxane modified graphene oxide.

The solid content of the modified waterborne polyurethane emulsion is 40 percent; the solid content of the aqueous acrylic emulsion was 40%.

The preparation method of the waterborne self-repairing wood lacquer comprises the following steps:

(1) the preparation method of the modified graphene oxide comprises the following steps:

(1.1) adding 0.5g of polydimethylsiloxane, 1.8g of n-heptane and 0.1g of tetraethyl orthosilicate into a three-neck flask, introducing nitrogen, stirring at 45 ℃, adding dibutyltin dilaurate, reacting for 10min, and drying at 100 ℃;

(1.2) putting 2g of graphene oxide and 100ml of hydrazine hydrate into a flask, stirring and heating, carrying out condensation reflux for 8 hours, taking out, adding dilute hydrochloric acid, washing to be neutral, and drying;

and (1.3) mixing the polydimethylsiloxane obtained in the step (1.1) with the graphene oxide obtained in the step (1.2), putting the mixture into a high-temperature furnace, and keeping the temperature at 350 ℃ for 4 hours to obtain the polydimethylsiloxane modified graphene oxide.

(2) The modified aqueous polyurethane emulsion is prepared by taking the modified graphene oxide as a raw material, and the specific method comprises the following steps:

(2.1) putting 20g of polytetrahydrofuran ether glycol into a container, heating and stirring, adding 6.5g of isophorone diisocyanate and dibutyltin dilaurate when the temperature is raised to 70 ℃, and reacting for 3h to obtain a prepolymer;

(2.2) mixing 1g of 2, 2-hydroxymethylpropionic acid and 0.04g of polydimethylsiloxane modified graphene oxide, adding the mixture into the prepolymer, and reacting for 5 hours;

and (2.3) adding 1g of 1, 4-butanediol, cooling to room temperature, adding 5g of triethylamine and 60g of deionized water, and dispersing to obtain the polydimethylsiloxane modified graphene oxide modified aqueous polyurethane emulsion.

(3) Mixing and stirring the modified waterborne polyurethane emulsion, the waterborne acrylic emulsion, a defoaming agent, a wetting agent, wax powder, a film-forming assistant, water, a defoaming agent and a thickening agent to obtain a finished product, wherein the specific method comprises the following steps:

(3.1) adding the modified waterborne polyurethane emulsion and the waterborne acrylic emulsion in proportion, stirring for 5min at the rotating speed of 1000r/min, sequentially adding the defoaming agent, stirring for 5min at the rotating speed of 1200r/min, respectively adding the wetting agent and the dispersing agent, stirring for 5min at the rotating speed of 1400r/min, reducing the stirring speed to 600r/min, adding the wax powder, stirring for 5min, and accelerating to 1600r/min, and stirring for 20min to obtain a first slurry;

(3.2) mixing the film-forming assistant and water in a ratio of 1: 1 to obtain a first mixed solution; adding the first mixed solution into the first slurry, stirring for 15min at the rotating speed of 1200r/min, reducing the stirring speed to 1000r/min, adding the thickening agent, and stirring for 8min to obtain second slurry;

(3.3) adjusting the viscosity of the second slurry to 65s, standing for 1h, and then filtering, wherein in the filtering process, a 200-mesh filter screen is used for filtering for 1 time, and then a 250-mesh filter screen is used for filtering for 1 time, so that the fineness of the water-based self-repairing wood paint is less than 25 micrometers, and a finished product is obtained.

Example 2

The water-based self-repairing wood lacquer comprises the following components in parts by weight:

60 parts of modified waterborne polyurethane emulsion, 10 parts of waterborne acrylic emulsion, 0.1 part of defoaming agent, 0.2 part of wetting agent, 1 part of wax powder, 3 parts of film-forming assistant, 3 parts of water and 0.1 part of thickening agent;

the modified aqueous polyurethane emulsion is modified graphene oxide modified aqueous polyurethane emulsion, and the modified graphene oxide is polydimethylsiloxane modified graphene oxide.

The solid content of the modified waterborne polyurethane emulsion is 35 percent; the solid content of the aqueous acrylic emulsion was 35%.

The preparation method of the waterborne self-repairing wood lacquer is different from the embodiment 1 in that: in the step (2.2), 1g of 2, 2-hydroxymethylpropionic acid and 0.08g of polydimethylsiloxane modified graphene oxide are mixed and added into the prepolymer to react for 5 hours, and the rest is the same.

Example 3

The water-based self-repairing wood lacquer comprises the following components in parts by weight:

70 parts of modified aqueous polyurethane emulsion, 20 parts of aqueous acrylic emulsion, 0.3 part of defoaming agent, 0.3 part of wetting agent, 2 parts of wax powder, 5 parts of film-forming assistant, 5 parts of water and 0.2 part of thickening agent;

the modified aqueous polyurethane emulsion is modified graphene oxide modified aqueous polyurethane emulsion, and the modified graphene oxide is polydimethylsiloxane modified graphene oxide.

The preparation method of the waterborne self-repairing wood lacquer is different from the embodiment 1 in that: in the step (2.2), 1g of 2, 2-hydroxymethylpropionic acid and 0.12g of polydimethylsiloxane modified graphene oxide are mixed and added into the prepolymer to react for 5 hours, and the rest is the same.

Example 4

The raw material formula of the water-based self-repairing wood paint is the same as that of the embodiment 1.

The preparation method of the waterborne self-repairing wood lacquer is different from the embodiment 1 in that: in the step (2.2), 1g of 2, 2-hydroxymethylpropionic acid and 0.16g of polydimethylsiloxane modified graphene oxide are mixed and added into the prepolymer to react for 5 hours, and the rest is the same.

Example 5

The raw material formula of the water-based self-repairing wood paint is the same as that of the embodiment 1.

The preparation method of the waterborne self-repairing wood lacquer is different from the embodiment 1 in that: in the step (2.2), 1g of 2, 2-hydroxymethylpropionic acid and 0.2g of polydimethylsiloxane modified graphene oxide are mixed and added into the prepolymer to react for 5 hours, and the rest is the same.

Example 6

The raw material formula of the water-based self-repairing wood paint is the same as that of the embodiment 1.

The preparation method of the water-based self-repairing wood lacquer is different from that of the embodiment 1 in the step (1), and the rest is the same.

The specific method of the step (1) is as follows:

(1.1) putting graphene oxide and hydrazine hydrate into a flask, stirring and heating, condensing and refluxing for 8 hours, taking out, adding dilute hydrochloric acid, washing to be neutral, and drying;

and (1.2) mixing polydimethylsiloxane with the graphene oxide obtained in the step (1.1), putting the mixture into a high-temperature furnace, and keeping the temperature at 350 ℃ for 4 hours to obtain the polydimethylsiloxane modified graphene oxide.

Example 7

The raw material formula of the water-based self-repairing wood paint is the same as that of the embodiment 1.

The preparation method of the water-based self-repairing wood lacquer is different from that of the embodiment 1 in the step (3), and the rest is the same.

The specific method of the step (3) is as follows:

mixing the modified waterborne polyurethane emulsion, the waterborne acrylic emulsion, a defoaming agent, a wetting agent, wax powder, a film-forming assistant, water, a defoaming agent and a thickening agent in proportion, stirring at the rotating speed of 1000r/min for 1h, adjusting the viscosity of the slurry to 65s, standing for 1h, and then filtering, wherein the filtering process comprises filtering for 1 time by using a 200-mesh filter screen and filtering for 1 time by using a 250-mesh filter screen, so that the fineness of the waterborne wood self-repairing paint is less than 25 mu m, and a finished product is obtained.

The performance test of the aqueous self-repairing wood lacquer obtained in the embodiment 1-7 is shown in table 1, and the test data shows that the aqueous self-repairing wood lacquer obtained in the invention has good mechanical strength and paint film performance and has certain flaw self-healing capability.

Table 1 shows the performance test results of the waterborne self-repairing wood paints obtained in examples 1 to 7