CN117965071A - Self-crosslinking exterior wall coating containing reinforcing fibers and preparation method thereof - Google Patents

Abstract

The invention discloses a self-crosslinking exterior wall coating containing reinforced fibers and a preparation method thereof, wherein the coating comprises the following components in percentage by mass: 10-20% of water, 0.1-0.5% of bentonite, 0.1-0.5% of cellulose, 3-8% of reinforcing fiber, 0.5-2% of glycol, 0.5-1.5% of dispersing agent, 0.1-0.5% of wetting agent, 0.1-0.3% of multifunctional auxiliary agent, 15-25% of titanium dioxide, 8-15% of precipitated barium sulfate, 2-8% of silane modified nano silicon dioxide, 5-10% of aqueous polyurethane emulsion, 30-40% of organosilicon modified acrylic emulsion, 1-3% of film forming auxiliary agent, 0.1-0.3% of bactericide, 0.1-0.2% of preservative, 0.5-1% of mildew preventive, 0.3-1.1% of defoaming agent and 0.5-1.8% of flatting agent. The coating of the paint has excellent artificial weather aging resistance, wear resistance, impact resistance, corrosion resistance and high hardness through the compounding of the organosilicon modified acrylic emulsion and the aqueous polyurethane emulsion and the addition of the silane modified nano silicon dioxide and the reinforcing fiber.

Description

Self-crosslinking exterior wall coating containing reinforcing fibers and preparation method thereof

Technical Field

The invention relates to a self-crosslinking exterior wall coating containing reinforcing fibers and a preparation method thereof, belonging to the technical field of coatings.

Background

The exterior wall coating has rich decorative colors, is convenient to construct, and can show various architectural styles. With the development of economy and the improvement of living standard of people in China, the emulsion paint with the characteristics of safety, low carbon, environmental protection and the like has become a main material for building facing in China, and is also an exterior wall facing material advocated and promoted by China.

The coating has low hardness, weak adhesive force and easy pulverization and falling off, is a common problem of the exterior wall coating, and restricts the popularization and application of the exterior wall coating to a great extent. Especially in areas with serious atmospheric pollution, the weather resistance of the exterior wall coating is still a technical problem. How to reasonably utilize the theory of the prior advanced exterior wall coating anti-fouling technology to develop the high-hardness weather-resistant coating is a key for solving the problems of low hardness and poor weather resistance of the prior exterior wall coating.

At present, solvent type exterior wall coating materials are used for solving the weather resistance problem, but the environment is not protected; in addition, some double-component polyurethane coatings have excellent performance, but the cost is too high, so that the popularization and application of the products are greatly limited.

Disclosure of Invention

The invention aims to provide a self-crosslinking exterior wall coating containing reinforcing fibers and a preparation method thereof, and the self-crosslinking exterior wall coating has excellent artificial weathering resistance, wear resistance, impact resistance, corrosion resistance and high hardness by compounding organosilicon modified acrylic emulsion and aqueous polyurethane emulsion and adding silane modified nano silicon dioxide and reinforcing fibers.

In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:

A self-crosslinking exterior wall coating containing reinforcing fibers comprising the following components in mass fraction:

10-20% of water, 0.1-0.5% of bentonite, 0.1-0.5% of cellulose, 3-8% of reinforcing fiber, 0.5-2% of glycol, 0.5-1.5% of dispersing agent, 0.1-0.5% of wetting agent, 0.1-0.3% of multifunctional auxiliary agent, 15-25% of titanium dioxide, 8-15% of precipitated barium sulfate, 2-8% of silane modified nano silicon dioxide, 5-10% of aqueous polyurethane emulsion, 30-40% of organosilicon modified acrylic emulsion, 1-3% of film forming auxiliary agent, 0.1-0.3% of bactericide, 0.1-0.2% of preservative, 0.5-1% of mildew preventive, 0.3-1.1% of defoaming agent and 0.5-1.8% of flatting agent.

Preferably, the preparation method of the reinforcing fiber comprises the following steps: adding lignin after the sulfamic acid and urea are eutectic to obtain a mixed solution; dispersing the mixed solution in deionized water added with matrix fibers, stirring, centrifuging, washing, and drying to obtain the reinforced fibers.

Preferably, the sulfamic acid and the urea are heated to be eutectic at 75-95 ℃ according to the mol ratio of 1 (2-5);

in the mixed solution, the mass fraction of lignin is 5-12%.

Preferably, the matrix fiber is one or more of alumina fiber, aluminum silicate fiber and mullite fiber.

Preferably, the mass ratio of the matrix fiber in the deionized water to the lignin in the mixed solution is 1 (1-3).

Preferably, the centrifugation conditions are 8000-12000rpm,5-10min; the drying condition is 40-60 ℃ for 15-30min.

Preferably, the preparation method of the organosilicon modified acrylic emulsion comprises the following steps: adding cyclosiloxane, allyl hydroxyethyl ether, acrylic acid and an emulsifier into deionized water, mixing, and then intermittently dripping ammonium persulfate to perform soap-free emulsion polymerization.

Preferably, the cyclosiloxane, the allyl hydroxyethyl ether, the acrylic acid, the ammonium persulfate, the deionized water and the emulsifier are respectively in parts by weight: 35-55 parts, 15-25 parts, 0.2-2 parts, 3-5 parts and 15-20 parts.

Preferably, the soap-free emulsion polymerization conditions are: the temperature is 80-90 ℃, and the reaction is 3-6h.

Any one of the preparation methods of the self-crosslinking exterior wall coating containing the reinforcing fiber comprises the following steps:

mixing water, bentonite, cellulose, glycol, a dispersing agent, a wetting agent and part of defoaming agent, and stirring to obtain a first blend;

adding a multifunctional auxiliary agent into the first blend, and stirring to obtain a second blend;

adding titanium dioxide and precipitated barium sulfate into the second blend, and stirring until the fineness is less than 50 mu m to obtain a third blend;

Adding reinforcing fibers, silane modified nano silicon dioxide, aqueous polyurethane emulsion, organosilicon modified acrylic emulsion, film forming auxiliary agent, bactericide, preservative, mildew inhibitor and the rest defoamer into the third blend, and stirring to obtain a fourth blend;

and adding a leveling agent into the fourth blend, and stirring to obtain the exterior wall coating.

The invention has the beneficial effects that:

1. The organosilicon modified acrylic emulsion has a hyperbranched structure, and has stronger intermolecular force, so that the organosilicon modified acrylic emulsion has higher viscosity, is beneficial to improving the uniformity and smoothness of a coating, and reduces the leveling time and the coating thickness during brushing; the hyperbranched structure has a longer main chain and a high branch structure, so that the coating has stronger oxidation resistance and ultraviolet radiation resistance, is beneficial to improving the weather resistance of the coating, and keeps good appearance and service performance in an outdoor environment; in addition, the hyperbranched polymer has larger molecular weight and complex branched structure, so that the hyperbranched polymer has stronger wear resistance and impact resistance, and contributes to improving the wear resistance and impact resistance of the coating.

The aqueous polyurethane emulsion has good weather resistance, wear resistance, impact resistance, chemical corrosion resistance and bonding strength, and the weather resistance is that the coating can effectively resist the influence of outdoor environment and keeps the appearance and the service performance unchanged. Meanwhile, the coating has good wear resistance and impact resistance, and can effectively protect the surface of the coated object from being influenced by abrasion and scratches. In addition, the aqueous polyurethane emulsion has good adhesive force and permeability, can effectively fill and repair tiny unevenness and cracks on the surface of a coated object, and improves the integrity and the aesthetic property of the coating.

Therefore, by compounding the organosilicon modified acrylic emulsion and the aqueous polyurethane emulsion, the performances of weather resistance, wear resistance, impact resistance and the like of the coating can be improved.

2. The silane modified nano silicon dioxide is added into the components as a special additive, so that the silane modified nano silicon dioxide has the characteristics of hydrophilicity and high hardness of inorganic matters, and meanwhile, the self nano structure of the silane modified nano silicon dioxide can be effectively dispersed among particles of a film forming material, so that the scratch resistance, the wear resistance and the hardness of a coating film can be improved, and the hardness of a coating layer can be improved.

3. By adding the reinforcing fiber into the components, the aminated lignin nano particles in the reinforcing fiber can be coated on the surface of the matrix fiber, so that on one hand, the dispersibility of the matrix fiber can be improved, and the high temperature resistance, corrosion resistance, heat insulation performance and mechanical property of the coating are improved by utilizing the matrix fiber; on the other hand, the weather resistance of the coating can be improved by utilizing the ultraviolet shielding effect of the aminated lignin nano particles on the surface of the matrix fiber.

Detailed Description

The present invention will be specifically described with reference to examples.

Example 1

The coating composition is as follows (unit:%):

The preparation method of the reinforcing fiber comprises the following steps: eutectic melting sulfamic acid and urea at 85 ℃ according to the mol ratio of 1:3, and adding lignin to obtain a mixed solution (lignin 5 wt%); dispersing the mixed solution in deionized water added with aluminum silicate fiber (the mass ratio of the aluminum silicate fiber to the lignin is 1:3), stirring for 30min at 600 r/min, centrifuging for 5min at 10000rpm by a centrifuge, taking down the substances and washing to be neutral, and drying for 20min at 55 ℃ to obtain the reinforced fiber.

The preparation method of the organosilicon modified acrylic emulsion comprises the following steps: adding 35 parts of cyclosiloxane, 22 parts of allyl hydroxyethyl ether, 18 parts of acrylic acid and 4.5 parts of emulsifier into 18 parts of deionized water, and uniformly mixing to obtain a pre-emulsion; dissolving 0.5 part of ammonium persulfate in 2 parts of deionized water to obtain an ammonium persulfate solution; and intermittently dripping the ammonium persulfate solution into the pre-emulsion at the temperature of 85 ℃ to react for 5 hours after the dripping is finished.

The preparation method of the exterior wall coating comprises the following steps:

S1, sequentially adding water, bentonite, cellulose, glycol, a dispersing agent, a wetting agent and a defoaming agent 334 into a reaction kettle, and uniformly stirring at a rotation speed of 500 revolutions per minute;

s2, adding the multifunctional auxiliary agent into the reaction kettle, and stirring for 5min at the rotation speed of 1200 revolutions per minute;

S3, adding titanium dioxide and precipitated barium sulfate into the reaction kettle, and stirring for 15min at the rotating speed of 1500 rpm until the fineness is less than 50 mu m;

s4, adding the reinforcing fiber, the silane modified nano silicon dioxide, the aqueous polyurethane emulsion, the organosilicon modified acrylic emulsion, the film forming additive, the bactericide, the preservative, the mildew inhibitor and the defoamer A10 into the reaction kettle, and stirring for 10min at the rotation speed of 1200 rpm;

s5, adding the leveling agent into the reaction kettle, and uniformly stirring at the rotating speed of 800 revolutions per minute.

Example 2

The coating composition is as follows (unit:%):

The preparation method of the reinforcing fiber comprises the following steps: eutectic melting sulfamic acid and urea at 85 ℃ according to the mol ratio of 1:3, and adding lignin to obtain a mixed solution (lignin 8 wt%); dispersing the mixed solution in deionized water added with aluminum silicate fiber (the mass ratio of the aluminum silicate fiber to the lignin is 1:3), stirring for 30min at 600 r/min, centrifuging for 5min at 10000rpm by a centrifuge, taking down the substances and washing to be neutral, and drying for 20min at 55 ℃ to obtain the reinforced fiber.

The preparation method of the organosilicon modified acrylic emulsion comprises the following steps: adding 40 parts of cyclosiloxane, 18 parts of allyl hydroxyethyl ether, 17 parts of acrylic acid and 4.5 parts of emulsifier into 18 parts of deionized water, and uniformly mixing to obtain a pre-emulsion; dissolving 0.5 part of ammonium persulfate in 2 parts of deionized water to obtain an ammonium persulfate solution; and intermittently dripping the ammonium persulfate solution into the pre-emulsion at the temperature of 85 ℃ to react for 5 hours after the dripping is finished.

The preparation method of the exterior wall coating comprises the following steps:

S1, sequentially adding water, bentonite, cellulose, glycol, a dispersing agent, a wetting agent and a defoaming agent 334 into a reaction kettle, and uniformly stirring at a rotation speed of 500 revolutions per minute;

s2, adding the multifunctional auxiliary agent into the reaction kettle, and stirring for 5min at the rotation speed of 1200 revolutions per minute;

S3, adding titanium dioxide and precipitated barium sulfate into the reaction kettle, and stirring for 15min at the rotating speed of 1500 rpm until the fineness is less than 50 mu m;

s4, adding the reinforcing fiber, the silane modified nano silicon dioxide, the aqueous polyurethane emulsion, the organosilicon modified acrylic emulsion, the film forming additive, the bactericide, the preservative, the mildew inhibitor and the defoamer A10 into the reaction kettle, and stirring for 10min at the rotation speed of 1200 rpm;

s5, adding the leveling agent into the reaction kettle, and uniformly stirring at the rotating speed of 800 revolutions per minute.

Example 3

The coating composition is as follows (unit:%):

The preparation method of the reinforcing fiber comprises the following steps: eutectic melting sulfamic acid and urea at 85 ℃ according to the mol ratio of 1:3, and adding lignin to obtain a mixed solution (lignin 10 wt%); dispersing the mixed solution in deionized water added with aluminum silicate fiber (the mass ratio of the aluminum silicate fiber to the lignin is 1:3), stirring for 30min at 600 r/min, centrifuging for 5min at 10000rpm by a centrifuge, taking down the substances and washing to be neutral, and drying for 20min at 55 ℃ to obtain the reinforced fiber.

The preparation method of the organosilicon modified acrylic emulsion comprises the following steps: adding 40 parts of cyclosiloxane, 20 parts of allyl hydroxyethyl ether, 15 parts of acrylic acid and 4.5 parts of emulsifier into 18 parts of deionized water, and uniformly mixing to obtain a pre-emulsion; dissolving 0.5 part of ammonium persulfate in 2 parts of deionized water to obtain an ammonium persulfate solution; and intermittently dripping the ammonium persulfate solution into the pre-emulsion at the temperature of 85 ℃ to react for 5 hours after the dripping is finished.

The preparation method of the exterior wall coating comprises the following steps:

S1, sequentially adding water, bentonite, cellulose, glycol, a dispersing agent, a wetting agent and a defoaming agent 334 into a reaction kettle, and uniformly stirring at a rotation speed of 500 revolutions per minute;

s2, adding the multifunctional auxiliary agent into the reaction kettle, and stirring for 5min at the rotation speed of 1200 revolutions per minute;

S3, adding titanium dioxide and precipitated barium sulfate into the reaction kettle, and stirring for 15min at the rotating speed of 1500 rpm until the fineness is less than 50 mu m;

s4, adding the reinforcing fiber, the silane modified nano silicon dioxide, the aqueous polyurethane emulsion, the organosilicon modified acrylic emulsion, the film forming additive, the bactericide, the preservative, the mildew inhibitor and the defoamer A10 into the reaction kettle, and stirring for 10min at the rotation speed of 1200 rpm;

s5, adding the leveling agent into the reaction kettle, and uniformly stirring at the rotating speed of 800 revolutions per minute.

Comparative example 1

The difference from example 3 is that lignin in the reinforcing fiber is not subjected to amination.

The preparation method of the reinforcing fiber comprises the following steps: dispersing lignin and aluminum silicate fiber in deionized water according to a mass ratio of 3:1, stirring for 30min at 600 rpm, centrifuging for 5min at 10000rpm by a centrifuge, taking down the substances, washing to neutrality, and drying at 55deg.C for 20min to obtain the reinforcing fiber.

The coating composition is as follows (unit:%):

The preparation method of the exterior wall coating comprises the following steps:

S1, sequentially adding water, bentonite, cellulose, glycol, a dispersing agent, a wetting agent and a defoaming agent 334 into a reaction kettle, and uniformly stirring at a rotation speed of 500 revolutions per minute;

s2, adding the multifunctional auxiliary agent into the reaction kettle, and stirring for 5min at the rotation speed of 1200 revolutions per minute;

S3, adding titanium dioxide and precipitated barium sulfate into the reaction kettle, and stirring for 15min at the rotating speed of 1500 rpm until the fineness is less than 50 mu m;

s4, adding the reinforcing fiber, the silane modified nano silicon dioxide, the aqueous polyurethane emulsion, the organosilicon modified acrylic emulsion, the film forming additive, the bactericide, the preservative, the mildew inhibitor and the defoamer A10 into the reaction kettle, and stirring for 10min at the rotation speed of 1200 rpm;

s5, adding the leveling agent into the reaction kettle, and uniformly stirring at the rotating speed of 800 revolutions per minute.

Comparative example 2

The difference from example 3 is that the coating composition of comparative example 2 is added with pure aluminum silicate fibers instead of reinforcing fibers.

The coating composition is as follows (unit:%):

The preparation method of the exterior wall coating comprises the following steps:

S1, sequentially adding water, bentonite, cellulose, glycol, a dispersing agent, a wetting agent and a defoaming agent 334 into a reaction kettle, and uniformly stirring at a rotation speed of 500 revolutions per minute;

s2, adding the multifunctional auxiliary agent into the reaction kettle, and stirring for 5min at the rotation speed of 1200 revolutions per minute;

S3, adding titanium dioxide and precipitated barium sulfate into the reaction kettle, and stirring for 15min at the rotating speed of 1500 rpm until the fineness is less than 50 mu m;

s4, adding aluminum silicate fiber, silane modified nano silicon dioxide, aqueous polyurethane emulsion, organosilicon modified acrylic emulsion, film forming additive, bactericide, preservative, mildew inhibitor and defoamer A10 into the reaction kettle, and stirring for 10min at a rotation speed of 1200 rpm;

s5, adding the leveling agent into the reaction kettle, and uniformly stirring at the rotating speed of 800 revolutions per minute.

The paint coatings obtained in examples 1-3 and comparative examples 1-2 were subjected to performance tests based on the following criteria: the state in the container, the low temperature stability, the workability, the drying time, the appearance of the coating film, the water resistance, the temperature deformation resistance, the water permeability, the artificial weather aging resistance, the pulverization and the color change performance of the coating are all carried out according to GB/T9755-2014; bond strength is performed according to JC/T2217-2014; the high-low temperature resistant cyclic alternating test is carried out according to the injection 1; impact resistance is carried out in accordance with GB/T1732-2020; hardness is carried out according to GB/T6739-2006; chemical resistance (acid, base) is carried out according to GB/T9274; wear resistance is performed in accordance with GB/T1768-2006.

The test results are shown in Table 1.

Table 1:

Note 1: high and low temperature resistant cyclic alternating test conditions: 80+/-2 ℃, 95% RH for 4 hours, 80 ℃ to-40 ℃ for 2 hours (the temperature changing speed is 1 ℃/min), 40+/-2 ℃ for 4 hours, 40 ℃ to 80 ℃ and 95% RH for 2 hours (the temperature changing speed is 1 ℃/min), 12 hours are a period, and a sample plate is placed for more than 16 hours at room temperature after the 60-period test is completed and then is tested; the method comprises the steps of performing a cross-cut test when the thickness of a coating is less than or equal to 300 mu m, performing an X-cut test when the thickness of the coating is less than or equal to 80 mu m, performing a cross-cut interval of 1mm when the thickness of the coating is less than or equal to 80 mu m, performing a cross-cut interval of 2mm when the thickness of the coating is 80-150 mu m, performing a cross-cut interval of 3mm when the thickness of the coating is 150-300 mu m, and performing an adhesive force of not less than grade 3.

As can be seen from the data in table 1, the coatings of the coatings provided in examples 1 to 3 have excellent artificial weathering resistance, abrasion resistance, impact resistance, corrosion resistance and high hardness, so it is known that the compounding of the organosilicon modified acrylic emulsion with the aqueous polyurethane emulsion, and the addition of the silane modified nano silica and the reinforcing fiber have a positive effect on improving the performance of the coatings. The coating of the coating provided in examples 1-3 has better resistance to artificial weathering, abrasion, impact, corrosion and high hardness than the coating of the coating provided in comparative examples 1-2, because the aminated lignin nanoparticles can better coat the surface of the matrix fiber, thereby improving the dispersibility of the matrix fiber, and the highly fully dispersed matrix fiber can better improve the abrasion and impact resistance of the coating while utilizing the matrix fiber to improve the high temperature, corrosion and heat resistance of the coating; secondly, the amination lignin nano particles on the surface of the matrix fiber have an ultraviolet shielding effect, so that the weather resistance (artificial weather aging resistance and neutral salt fog resistance) of the coating is improved.

The foregoing is merely illustrative of the preferred embodiments of this invention, and it will be appreciated by those skilled in the art that variations and modifications may be made without departing from the principles of this invention, and such variations and modifications are to be regarded as being within the scope of this invention.

Claims (10)

1. A self-crosslinking exterior wall coating containing reinforcing fibers, characterized by comprising the following components in mass fraction:

10-20% of water, 0.1-0.5% of bentonite, 0.1-0.5% of cellulose, 3-8% of reinforcing fiber, 0.5-2% of glycol, 0.5-1.5% of dispersing agent, 0.1-0.5% of wetting agent, 0.1-0.3% of multifunctional auxiliary agent, 15-25% of titanium dioxide, 8-15% of precipitated barium sulfate, 2-8% of silane modified nano silicon dioxide, 5-10% of aqueous polyurethane emulsion, 30-40% of organosilicon modified acrylic emulsion, 1-3% of film forming auxiliary agent, 0.1-0.3% of bactericide, 0.1-0.2% of preservative, 0.5-1% of mildew preventive, 0.3-1.1% of defoaming agent and 0.5-1.8% of flatting agent.

2. The self-crosslinking exterior wall coating containing reinforcing fibers of claim 1, wherein the reinforcing fibers are prepared by the following steps: adding lignin after the sulfamic acid and urea are eutectic to obtain a mixed solution; dispersing the mixed solution in deionized water added with matrix fibers, stirring, centrifuging, washing, and drying to obtain the reinforced fibers.

3. The self-crosslinking exterior wall coating containing reinforcing fibers according to claim 2, wherein the sulfamic acid and urea are heated to eutectic at 75-95 ℃ in a molar ratio of 1 (2-5);

in the mixed solution, the mass fraction of lignin is 5-12%.

4. The self-crosslinking exterior wall coating containing reinforcing fibers of claim 2, wherein the matrix fibers are one or more combinations of alumina fibers, aluminum silicate fibers, and mullite fibers.

5. The self-crosslinking exterior wall coating containing reinforcing fibers according to claim 2, wherein the mass ratio of the matrix fibers in the deionized water to lignin in the mixed solution is 1 (1-3).

6. The self-crosslinking exterior wall coating containing reinforcing fibers of claim 2, wherein the centrifugation conditions are 8000-12000rpm for 5-10min; the drying condition is 40-60 ℃ for 15-30min.

7. The self-crosslinking exterior wall coating containing reinforcing fibers according to claim 1, wherein the preparation method of the organosilicon modified acrylic emulsion is as follows: adding cyclosiloxane, allyl hydroxyethyl ether, acrylic acid and an emulsifier into deionized water, mixing, and then intermittently dripping ammonium persulfate to perform soap-free emulsion polymerization.

8. The self-crosslinking exterior wall coating containing reinforcing fibers according to claim 7, wherein the cyclosiloxane, the allyl hydroxyethyl ether, the acrylic acid, the ammonium persulfate, the deionized water and the emulsifier are respectively in parts by weight: 35-55 parts, 15-25 parts, 0.2-2 parts, 3-5 parts and 15-20 parts.

9. The self-crosslinking exterior wall coating containing reinforcing fibers of claim 7, wherein the soap-free emulsion polymerization conditions are: the temperature is 80-90 ℃, and the reaction is 3-6h.

10. A method for preparing the self-crosslinking exterior wall coating containing reinforcing fibers according to any one of claims 1 to 9, comprising the steps of:

mixing water, bentonite, cellulose, glycol, a dispersing agent, a wetting agent and part of defoaming agent, and stirring to obtain a first blend;

adding a multifunctional auxiliary agent into the first blend, and stirring to obtain a second blend;

adding titanium dioxide and precipitated barium sulfate into the second blend, and stirring until the fineness is less than 50 mu m to obtain a third blend;

Adding reinforcing fibers, silane modified nano silicon dioxide, aqueous polyurethane emulsion, organosilicon modified acrylic emulsion, film forming auxiliary agent, bactericide, preservative, mildew inhibitor and the rest defoamer into the third blend, and stirring to obtain a fourth blend;

and adding a leveling agent into the fourth blend, and stirring to obtain the exterior wall coating.