CN105670514B - The method of the nanometer particle-modified water-borne wood coating of nano-cellulose hybrid inorganic - Google Patents

Abstract

The invention discloses a method for modifying water-based wood coatings with nano-cellulose hybrid inorganic nanoparticles, which relates to a modification method of water-based wood coatings. The purpose of the present invention is to solve the poor dispersion of existing inorganic nanoparticles in water-based wood coatings, the low aspect ratio of organic nanocellulose rod crystals, resulting in poor mechanical properties of modified water-based wood coatings, and weather resistance and even sterilization and air purification functions Improve poor problems. Methods: 1. Preparation of nano-cellulose aqueous solution: 2. Hybrid compounding of nano-cellulose and inorganic nanoparticles; 3. Composite of nano-materials and water-based resin emulsion to obtain nano-cellulose hybrid inorganic nanoparticles modified water-based wood coating. The invention utilizes one-dimensional nanocellulose with high specific surface area and good water dispersibility as a carrier, in situ doping and compounding zero-dimensional inorganic nanoparticles, and synergistically improves the comprehensive performance of water-based wood coatings through the method of two-phase in-situ hybridization and compounding. To broaden the scope of application of water-based wood coatings.

Description

Method for modifying waterborne wood coatings by nanocellulose hybrid inorganic nanoparticles

technical field

The invention relates to a modification method of water-based wood paint.

Background technique

Wood has natural defects such as easy to absorb water, swell and deform, susceptible to fungal decay, susceptible to ultraviolet light aging, and easy to burn and degrade. Therefore, wood coatings are often painted on the surface of wood to improve the above defects. However, with the strengthening of people's awareness of environmental protection, the application of organic oil-soluble coatings with high VOC emissions has become more and more restricted, while environmentally friendly water-based coatings with low VOC emissions have become more and more popular and become the mainstream trend in the development of wood coatings. However, the scratch resistance, abrasion resistance, hardness, impact resistance and other mechanical properties of water-based wood coatings, as well as UV aging resistance are generally inferior to oil-based coatings with mature technology, so it is necessary to improve their performance.

In recent years, patents on the modification of waterborne wood coatings using nanomaterials have been reported. As described in the invention patent with application number 201210480069.X, the use of nano-TiO ₂ , Al ₂ O ₃ , SiO ₂ , and Ag composite water-based resin emulsion to make water-based wood coatings have antibacterial properties, but the direct doping of nanoparticles is easy to agglomerate, and The poor compatibility of the matrix resin interface leads to phase separation and other problems, so the mechanical strength of the water-based coating cannot be effectively enhanced. At the same time, the introduction of Ag will cause the water-based wood coating to have obvious color difference and reduce the light transmittance and gloss of the coating. The invention patent with the application number 201380049182.5 reports the preparation method of adding nanocellulose and surfactants to water-based coatings, but the addition of nanocellulose has no positive effect on the scratch resistance, abrasion resistance and UV aging resistance of the coating. effect. The invention patent with the application number 201310588309.2 reported the use of nanocellulose rod crystals to improve the mechanical properties of water-based wood coatings such as hardness and wear resistance, and solved the problem of uniform dispersion of nanocellulose in situ, but it could not improve the UV aging resistance. And the improvement of scratch resistance and impact toughness is not obvious due to the low aspect ratio. The invention patent with the application number 201510647618.1 reported the in-situ composite of nano-cellulose crystals and TiO ₂ , and improved its dispersion in polydimethylsiloxane PDMS and the interfacial bonding force between them through stearic acid modification. layer preparation method, so that the coating has super-hydrophobic properties, but the nanocellulose used is a rod-shaped crystal with a small aspect ratio, and the improvement of the mechanical properties of the coating such as impact resistance and scratch resistance is limited, and the preparation is Oil-soluble paints release large organic VOCs, which is not the development trend of modern paints. The invention patent with the application number 201410006256.3 reports the method of preparing superhydrophobic wood coatings by using nanocellulose and nanosilica sol combined with water-dispersed resin, but nanocellulose loaded nanosilica is first superhydrophobic modified, so that The polarity difference between it and the water-dispersed resin is huge, the affinity between the two phases is poor, and the interface compatibility is poor. The superhydrophobic modified nanomaterials are easy to agglomerate, resulting in poor improvement or even decline in the mechanical properties of the coating.

In short, the inorganic nanoparticles modified water-based wood coatings stated in the above-mentioned published patents have the problems of poor dispersion of nanoparticles, poor mechanical properties of the coating, and poor improvement of light transmittance; and organic nanocellulose is mostly rod-shaped nanofibers. Plain crystals, low aspect ratio, have limited improvement in the impact toughness, scratch resistance, and wear resistance of the coating, and cannot improve the weather resistance of the coating; even if nanocellulose is compounded with SiO ₂ and TiO ₂ , the The adopted method also has the problems of poor affinity with the polymer matrix and poor dispersibility in the polymer matrix, resulting in poor improvement of the mechanical properties of the coating.

Contents of the invention

The purpose of the present invention is to solve the poor dispersion of existing inorganic nanoparticles in water-based wood coatings, the low aspect ratio of organic nanocellulose rod crystals, resulting in poor mechanical properties of modified water-based wood coatings, and weather resistance and even sterilization and air purification functions To improve the unsatisfactory problem, and provide a method for modifying water-based wood coatings with nano-cellulose hybrid inorganic nanoparticles.

The method for modifying water-based wood coatings by nano-cellulose hybrid inorganic nanoparticles is specifically completed according to the following steps:

1. Preparation of nanocellulose aqueous liquid: the cellulose raw material is sequentially subjected to extraction treatment, de-lignification treatment and de-hemicellulose treatment to obtain purified cellulose, and the purified cellulose is subjected to biological pretreatment or chemical pretreatment to obtain Nanocellulose aqueous solution;

The biological pretreatment refers to cellulase pretreatment, and the specific operation is as follows: add purified cellulose to a 250mL beaker, add deionized water until the mass fraction of purified cellulose is 0.1% to 0.3%, add cellulase, Pretreat at 50°C for 2 hours, then treat at 90°C for 2 hours, vacuum filter and wash with water, then remake cellulose aqueous solution with a mass concentration of 0.1% to 0.3%, and then undergo a 600bar high-pressure homogeneous mechanical treatment 30min to obtain the nanocellulose aqueous solution;

Put the purified cellulose into a 250mL beaker, add deionized water until the mass fraction is 0.1% to 0.3%, add sodium bromide and TEMPO reagent in turn, and add 5mL mass at a rate of 2.5mL/min under magnetic stirring. Sodium hypochlorite solution with a concentration of 12%, and then use sodium hydroxide with a concentration of 0.5mol/L to adjust the pH value to 10-10.5, and continue the reaction until the pH value does not change. After filtering and washing with water, put the obtained oxidized cellulose into a 250mL Erlenmeyer flask, add 70mL deionized water and 0.6g sodium chlorite, adjust the pH value to 4~5 with glacial acetic acid, and then magnetically stir at 70°C 1h, suction filtration, washing with water to obtain carboxylated cellulose, and then reconstitute 0.1% to 0.3% carboxylated cellulose aqueous solution, and then mechanically disperse with a high-speed mixer at 15,000rpm for 4min, and perform 5 times of high-pressure homogeneous mechanical treatment at 600bar. Ultrasound under 320W power for 30min to prepare nanocellulose aqueous solution;

The cellulose raw material described in step 1 is wood powder with a particle size of 60 mesh or more, crop straw powder or waste paper with a particle size of 60 mesh or more;

2. Hybrid compounding of nanocellulose and inorganic nanoparticles: add zero-dimensional inorganic nanoparticles to the nanocellulose aqueous solution obtained in step 1, and perform ultrasonic treatment for 30 minutes to 240 minutes at a power of 300W～1000W to obtain inorganic nanoparticle Hybrid composite liquid with uniform dispersion of particles and nanocellulose;

3. Composite of nanomaterials and water-based resin emulsion: ①. Add cationic surfactant to the hybrid composite solution, and ultrasonically treat it under the power of 300W-1000W for 30min-240min to obtain the primary mixture; ②. For the primary mixture Carry out rotary steaming until the remaining solution of rotary steaming is 1/5~1/2 of the volume of the original mixture, then add the remaining solution of rotary steaming to the water-based wood coating, and perform ultrasonic treatment under the power of 300W~1000W for 30min~240min, Obtain the mixed paint; ③, stir the mixed paint with a high-speed mixer at a speed of 15000 rpm for 30 minutes to obtain the nanocellulose hybrid inorganic nanoparticle modified water-based wood paint.

Advantages of the present invention: the present invention proposes a one-dimensional nanocellulose with high specific surface area and good water dispersibility as a carrier, in situ doped composite nano SiO ₂ , Al ₂ O ₃ , TiO ₂ , ZnO, CeO ₂ Equal zero-dimensional inorganic nanoparticles, synergistically improve the mechanical properties of water-based wood coatings such as scratch resistance, wear resistance, hardness, impact resistance and UV aging resistance through the method of two-phase in-situ hybridization, and even endow them with sterilization and air purification The function can significantly improve the service life of water-based wood coatings, increase the function of water-based wood coatings, broaden the application range of water-based wood coatings, and increase the added value of wood products. The advantages of the invention are given in conjunction with the advantages stated in the examples.

Description of drawings

Fig. 1 is the nanocellulose TEM figure in the nanocellulose aqueous liquid that embodiment 1 step one obtains;

Fig. 2 is the nanocellulose hybrid inorganic nanoparticle modified water-based wood coating SEM figure that embodiment 1 obtains;

Fig. 3 is the nanocellulose TEM figure in the nanocellulose aqueous liquid that embodiment 2 step one obtains;

Fig. 4 is the SEM image of the nanocellulose hybrid inorganic nanoparticle modified waterborne wood coating obtained in Example 2.

detailed description

Specific embodiment one: present embodiment is the method for nano-cellulose hybrid inorganic nanoparticle modified water-based wood coating, specifically completes according to the following steps:

1. Preparation of nanocellulose aqueous liquid: the cellulose raw material is sequentially subjected to extraction treatment, de-lignification treatment and de-hemicellulose treatment to obtain purified cellulose, and the purified cellulose is subjected to biological pretreatment or chemical pretreatment to obtain Nanocellulose aqueous solution;

The biological pretreatment refers to cellulase pretreatment, and the specific operation is as follows: add purified cellulose to a 250mL beaker, add deionized water until the mass fraction of purified cellulose is 0.1% to 0.3%, add cellulase, Pretreat at 50°C for 2 hours, then treat at 90°C for 2 hours, vacuum filter and wash with water, then remake cellulose aqueous solution with a mass concentration of 0.1% to 0.3%, and then undergo a 600bar high-pressure homogeneous mechanical treatment 30min to obtain the nanocellulose aqueous solution;

Put the purified cellulose into a 250mL beaker, add deionized water until the mass fraction is 0.1% to 0.3%, add sodium bromide and TEMPO reagent in turn, and add 5mL mass at a rate of 2.5mL/min under magnetic stirring. Sodium hypochlorite solution with a concentration of 12%, and then use sodium hydroxide with a concentration of 0.5mol/L to adjust the pH value to 10-10.5, and continue the reaction until the pH value does not change. After filtering and washing with water, put the obtained oxidized cellulose into a 250mL Erlenmeyer flask, add 70mL deionized water and 0.6g sodium chlorite, adjust the pH value to 4~5 with glacial acetic acid, and then magnetically stir at 70°C 1h, suction filtration, washing with water to obtain carboxylated cellulose, and then reconstitute 0.1% to 0.3% carboxylated cellulose aqueous solution, and then mechanically disperse with a high-speed mixer at 15,000rpm for 4min, and perform 5 times of high-pressure homogeneous mechanical treatment at 600bar. Ultrasound under 320W power for 30min to prepare nanocellulose aqueous solution;

The cellulose raw material described in step 1 is wood powder with a particle size of 60 mesh or more, crop straw powder or waste paper with a particle size of 60 mesh or more;

2. Hybrid compounding of nanocellulose and inorganic nanoparticles: add zero-dimensional inorganic nanoparticles to the nanocellulose aqueous solution obtained in step 1, and perform ultrasonic treatment for 30 minutes to 240 minutes at a power of 300W～1000W to obtain inorganic nanoparticle Hybrid composite liquid with uniform dispersion of particles and nanocellulose;

3. Composite of nanomaterials and water-based resin emulsion: ①. Add cationic surfactant to the hybrid composite solution, and ultrasonically treat it under the power of 300W-1000W for 30min-240min to obtain the primary mixture; ②. For the primary mixture Carry out rotary steaming until the remaining solution of rotary steaming is 1/5~1/2 of the volume of the original mixture, then add the remaining solution of rotary steaming to the water-based wood coating, and perform ultrasonic treatment under the power of 300W~1000W for 30min~240min, Obtain the mixed paint; ③, stir the mixed paint with a high-speed mixer at a speed of 15000 rpm for 30 minutes to obtain the nanocellulose hybrid inorganic nanoparticle modified water-based wood paint.

The extraction treatment described in step 1 of this embodiment: wrap the cellulose raw material with filter paper and put it into a 250mL Soxhlet extractor, then add 240mL of toluene-ethanol mixed solution as the extraction solvent, and put it in a water bath for 90 Extract at ℃ for 10 hours, remove the extractive components, and obtain wood powder from which the extractive components have been removed; the volume ratio of toluene to ethanol in the toluene-ethanol mixed solution is 2:1.

The delignification treatment described in step 1 of the present embodiment: ①, put the wood powder obtained above to remove the extractive components into a 500mL wide-mouth conical flask, add glacial acetic acid, sodium chlorite and deionized water to mix Solution, 300mL in total, and sealed with plastic wrap; among them, glacial acetic acid is 0.2mL, sodium chlorite is 1g, and the remaining liquid is water; then, place the Erlenmeyer flask containing the above mixed solution in a constant temperature water bath at 75°C Stir magnetically for 1 hour to obtain a mixed solution; ②. Add 0.2 mL of glacial acetic acid and 1 g of sodium chlorite to the resulting mixed solution, and then magnetically heat and stir in a constant temperature water bath at 75 ° C for 1 hour; ③ Repeat steps ② Operate 4 times, vacuum filter with glass filter or Buchner funnel at 0.08MPa, and wash continuously with distilled water until the filtrate is neutral, and finally until the anhydrous liquid is filtered out, the process of delignification is completed, and the cellulose is obtained;

The hemicellulose-removing treatment described in step 1 of this embodiment: put the hemicellulose obtained above into a 500 mL wide-mouthed Erlenmeyer flask that has been rinsed with a potassium hydroxide solution with a mass concentration of 5%, and pour it into 300mL potassium hydroxide solution with a mass concentration of 5%, seal the mouth of the cup with plastic wrap, and let it stand at room temperature for 12 hours to make the lye fully swell the fibers; then put it into a 90°C constant temperature water bath and heat and stir for 2 hours; the reaction is over Finally, use a Buchner funnel or a glass filter to carry out vacuum filtration at 0.08 MPa, and repeatedly wash with distilled water until the filtrate is neutral, and finally until the anhydrous liquid is filtered out, the process of removing hemicellulose is completed to obtain purified cellulose.

Specific embodiment two: the difference between this embodiment and specific embodiment one is: in the biological pretreatment process described in step one, the quality ratio of adding cellulase to the nanocellulose mass ratio in the nanocellulose aqueous liquid is 2: 1. Others are the same as the first embodiment.

Specific embodiment three: the difference between this embodiment and specific embodiment one or two is: sodium bromide in the chemical pretreatment process described in step one: TEMPO reagent: the quality of nanocellulose in nanocellulose aqueous liquid The ratio is 100:16:1000. Others are the same as those in Embodiment 1 or 2.

Embodiment 4: The difference between this embodiment and Embodiments 1 to 3 is that the zero-dimensional inorganic nanoparticles described in step 2 are any one of SiO ₂ , Al ₂ O ₃ , TiO ₂ , ZnO and CeO ₂ a combination of one or more. Others are the same as the specific embodiments 1 to 3.

Embodiment 5: This embodiment differs from Embodiment 1 to Embodiment 4 in that: the particle size of the zero-dimensional inorganic nanoparticles described in Step 2 is 10 nm to 30 nm. Others are the same as the specific embodiments 1 to 4.

Specific embodiment six: the difference between this embodiment and one of specific embodiments one to five is: the mass ratio of nanocellulose in the nanocellulose aqueous liquid obtained by the zero-dimensional inorganic nanoparticles described in step 2 and step 1 is ( 1～5):10. Others are the same as the specific embodiments 1 to 5.

Specific embodiment seven: the difference between this embodiment and specific embodiment one to six is: the cationic surfactant described in step 3 is hexadecyl trimethyl ammonium bromide, octadecyl trimethyl bromide Any one or a combination of ammonium chloride, cetyltrimethylammonium chloride or octadecyltrimethylammonium chloride. Others are the same as the specific embodiments 1 to 6.

Embodiment 8: This embodiment differs from Embodiment 1 to Embodiment 7 in that the water-based wood coating described in step 3 is water-based polyurethane acrylic resin coating or water-based acrylic resin coating. Others are the same as those in Embodiments 1 to 7.

The water-based polyurethane acrylic wood coating or water-based acrylic wood coating described in this embodiment is purchased from Carpoly Chemical Group Co., Ltd.

Specific embodiment nine: the difference between this embodiment and specific embodiments one to eight is: the water-based polyurethane acrylic resin coating described in step 3 is composed of water-based polyurethane acrylic resin, deionized water and curing agent, and the water-based polyurethane acrylic resin The solid content of the wood coating is 30%, the solid content of the curing agent in the water-based polyurethane acrylic wood coating is 0.5% to 1%, and the curing agent is an amino resin low-temperature self-crosslinking curing agent or an acyl phosphorus oxide Class ultraviolet light curing agent; Or described water-based acrylic wood coating is made up of water-based acrylic resin, deionized water and curing agent, and the solid content of described water-based acrylic wood coating is 30%, and curing in described water-based acrylic wood coating 0.5% to 1% of the solid content of the curing agent, and the curing agent is an amino resin low-temperature self-crosslinking curing agent or an acyl phosphorus oxide ultraviolet curing agent. Others are the same as the specific embodiments 1 to 8.

Embodiment 10: The difference between this embodiment and Embodiment 1 to Embodiment 9 is that the mass ratio of the cationic surfactant described in Step 3 ① to the nanocellulose in the hybrid composite liquid is (0.5～1): 100; the mass ratio of the solid mass in the water-based wood coating to the nanocellulose in the remaining solution of the rotary steaming described in step 2. is 100:(0.2-0.8). Others are the same as the specific embodiments 1 to 9.

Adopt following test verification effect of the present invention

Embodiment 1: the method for nano-cellulose hybrid inorganic nanoparticle modified water-based wood coating, specifically completes according to the following steps:

1. Preparation of nano-cellulose aqueous solution: the cellulose raw material is sequentially subjected to extraction treatment, de-lignification treatment and de-hemicellulose treatment to obtain purified cellulose, and biological pretreatment is performed on the purified cellulose to obtain nano-cellulose water liquid;

Extraction treatment described in step 1: Wrap 3g of cellulose raw material with filter paper and put it into a 250mL Soxhlet extractor, then add 240mL of toluene-ethanol mixed solution as the extraction solvent, in a water bath at 90°C Extract for 10h, remove the extractive components, and obtain the wood powder from which the extractive components are removed; the volume ratio of toluene and ethanol in the toluene-ethanol mixed solution is 2:1;

The cellulose raw material described in step 1 is wood powder with a particle size of 120 mesh;

The delignification treatment described in step 1: 1. Put the wood powder obtained above to remove the extractive components in a 500mL wide-mouth conical flask, add a mixed solution of glacial acetic acid, sodium chlorite and deionized water, and add a total of 300mL, and sealed with plastic wrap; among them, glacial acetic acid is 0.2mL, sodium chlorite is 1g, and the remaining liquid is water; then, place the Erlenmeyer flask containing the above mixed solution in a constant temperature water bath at 75°C for magnetic heating Stir for 1 hour to obtain a mixed solution; ②, add 0.2 mL of glacial acetic acid and 1 g of sodium chlorite to the obtained mixed solution, and then magnetically heat and stir in a constant temperature water bath at 75 °C for 1 hour; ③, repeat step ② for 4 times , use a glass filter or a Buchner funnel to vacuum filter at 0.08MPa, and continuously wash with distilled water until the filtrate is neutral, and finally until the anhydrous liquid is filtered out, the delignification process is completed, and the hemcellulose is obtained;

The hemicellulose-removing treatment described in step 1: put the above-mentioned obtained hemicellulose into 500 mL of a wide-mouthed Erlenmeyer flask that has been rinsed with a 5% potassium hydroxide solution in mass concentration, and pour it into a 300-mL mass concentration It is 5% potassium hydroxide solution, seal the mouth of the cup with plastic wrap, and let it stand at room temperature for 12 hours to make the lye fully swell the fibers; then put it into a 90°C constant temperature water bath and heat and stir for 2 hours; after the reaction, use Carry out vacuum filtration with Buchner funnel or glass filter at 0.08MPa, and repeatedly wash with distilled water until the filtrate is neutral, and finally until the anhydrous liquid is filtered out, the hemicellulose removal process is completed to obtain purified cellulose;

The biological pretreatment described in step 1 refers to cellulase pretreatment, and the specific operation is as follows: add purified cellulose to a 250mL beaker, add deionized water until the mass fraction of purified cellulose is 0.1%, add cellulase, Pretreat at 50°C for 2 hours, then treat at 90°C for 2 hours, vacuum filter and wash with water, reconstitute a cellulose aqueous solution with a mass concentration of 0.1%, and then undergo a 600bar high-pressure homogeneous mechanical treatment for 30 minutes, that is, Obtain nanocellulose aqueous solution;

2. Hybrid compounding of nanocellulose and inorganic nanoparticles: get 200mL of 0.1% concentration of nanocellulose aqueous solution obtained in step 1, add 0.05g of nano-SiO with a particle size of 30nm and 0.05g of nano _- SiO with a particle size of 10nm The nano-ZnO particles were subjected to ultrasonic treatment for 30 minutes at a power of 800W to obtain a hybrid composite solution;

3. Composite of nanomaterials and water-based resin emulsion: ①. Add cationic surfactant to the hybrid compound liquid, and perform ultrasonic treatment for 30 minutes under the power of 300W to obtain the primary mixture; ②. Rotate the primary mixture, Until the remaining solution of the rotary steaming is 1/5 of the volume of the original mixture, the remaining solution of the rotary steaming is added to 134mL of water-based wood coatings, and the ultrasonic treatment is carried out under the power of 300W for 30min to obtain the mixed coating; ③. Stir and mix the coating at a high speed of 15,000 rpm for 30 minutes to obtain the nanocellulose hybrid inorganic nanoparticle modified water-based wood coating. Wherein, the mass ratio of the cationic surfactant described in step 3.1 and the nanocellulose in the hybrid composite liquid is 1:100; the cationic surfactant described in step 3.1. is hexadecyl trimethyl bromide Ammonium chloride; Step 3. The mass ratio of nanocellulose in the water-based wood coating described in 2. in the water-based wood coating and the rotary steaming remaining solution is 100:0.5; Step 3. The water-based wood coating described in 2. is a water-based polyurethane acrylic resin coating, wherein Described water-based polyurethane acrylic resin coating is made up of water-based polyurethane acrylic resin, deionized water and curing agent, and the solid content of described water-based polyurethane acrylic wood coating is 30%, and the solid content of curing agent in the described water-based polyurethane acrylic wood coating The content is 1%, and the curing agent is an amino resin low-temperature self-crosslinking curing agent.

Fig. 1 is the TEM figure of nanocellulose in the nanocellulose aqueous liquid obtained in step one of embodiment 1, and the fiber diameter of nanocellulose in the nanocellulose aqueous liquid obtained in step one of embodiment 1 is shown by Fig. 1 to be in the range of 30nm to 50nm , the length is tens of microns, and the aspect ratio is greater than 1000, indicating that the nanocellulose in the aqueous nanocellulose solution obtained in step 1 of Example 1 has a fine and uniform structure and a large aspect ratio.

Fig. 2 is the nano-cellulose hybrid inorganic nanoparticle modified water-based wood coating SEM figure that embodiment 1 obtains, shows the nanoparticle in the nano-cellulose hybrid inorganic nano-particle modified water-based wood coating that embodiment 1 obtains It is evenly dispersed on the cellulose film, indicating that nanocellulose as a carrier effectively solves the dispersion problem of inorganic nanoparticles.

The nanocellulose hybrid inorganic nanoparticle modified water-based wood coating obtained in Example 1 and the unmodified wood coating were applied to the surface of maple wood by spraying at a spraying amount of 120 g/m ² , and dried at 35°C for 72h Afterwards, the nano-cellulose hybrid inorganic nanoparticle modified water-based wood coating paint film obtained in Example 1 and the unmodified wood coating paint film were obtained, and the mechanical properties, gloss, UV aging resistance and Bactericidal properties, the results show that the hardness of the nano-cellulose hybrid inorganic nanoparticle modified water-based wood coating film obtained in embodiment 1 has improved by 28.7% compared with the unmodified wood coating film, and the abrasion resistance has improved by 36.2%. Scratch resistance increased by 10%, impact toughness increased by 27.4%, glossiness decreased by only 15.6%, UV aging resistance increased by nearly 1 times, and mold load rate on the surface of the paint film decreased by more than 80%, indicating that This method can effectively improve the comprehensive performance of waterborne wood coatings and endow them with bactericidal function.

Embodiment 2: the method for nano-cellulose hybrid inorganic nano-particle modified water-based wood coatings is specifically completed in the following steps:

1. Preparation of nanocellulose aqueous solution: the cellulose raw material is sequentially subjected to extraction treatment, de-lignification treatment and hemicellulose treatment to obtain purified cellulose, and chemical pretreatment is performed on the purified cellulose to obtain nano-cellulose aqueous solution. liquid;

Extraction treatment described in step 1: Wrap 3g of cellulose raw material with filter paper and put it into a 250mL Soxhlet extractor, then add 240mL of toluene-ethanol mixed solution as the extraction solvent, in a water bath at 90°C Extract for 10h, remove the extractive components, and obtain the wood powder from which the extractive components are removed; the volume ratio of toluene and ethanol in the toluene-ethanol mixed solution is 2:1;

The cellulose raw material described in step 1 is wood powder with a particle size of 120 mesh;

The delignification treatment described in step 1: 1. Put the wood powder obtained above to remove the extractive components in a 500mL wide-mouth conical flask, add a mixed solution of glacial acetic acid, sodium chlorite and deionized water, and add a total of 300mL, and sealed with plastic wrap; among them, glacial acetic acid is 0.2mL, sodium chlorite is 1g, and the remaining liquid is water; then, place the Erlenmeyer flask containing the above mixed solution in a constant temperature water bath at 75°C for magnetic heating Stir for 1 hour to obtain a mixed solution; ②, add 0.2 mL of glacial acetic acid and 1 g of sodium chlorite to the obtained mixed solution, and then magnetically heat and stir in a constant temperature water bath at 75 °C for 1 hour; ③, repeat step ② for 4 times , use a glass filter or a Buchner funnel to vacuum filter at 0.08MPa, and continuously wash with distilled water until the filtrate is neutral, and finally until the anhydrous liquid is filtered out, the delignification process is completed, and the hemcellulose is obtained;

The hemicellulose-removing treatment described in step 1: put the above-mentioned obtained hemicellulose into 500 mL of a wide-mouthed Erlenmeyer flask that has been rinsed with a 5% potassium hydroxide solution in mass concentration, and pour it into a 300-mL mass concentration It is 5% potassium hydroxide solution, seal the mouth of the cup with plastic wrap, and let it stand at room temperature for 12 hours to make the lye fully swell the fibers; then put it into a 90°C constant temperature water bath and heat and stir for 2 hours; after the reaction, use Carry out vacuum filtration with Buchner funnel or glass filter at 0.08MPa, and repeatedly wash with distilled water until the filtrate is neutral, and finally until the anhydrous liquid is filtered out, the hemicellulose removal process is completed to obtain purified cellulose;

The chemical pretreatment described in step 1 refers to TEMPO oxidation treatment, and the specific operation is as follows: put the purified cellulose into a 250mL beaker, add deionized water until the mass fraction is 0.25%, add 0.25g sodium bromide and 0.025 gTEMPO (2,2,6,6-tetramethylpiperidine oxide), under magnetic stirring, add 5 mL of sodium hypochlorite solution with a mass concentration of 12% at a rate of 2.5 mL/min, and then use a concentration of 0.5 mol/L sodium hydroxide to adjust the pH value to 10-10.5, and continue the reaction until the pH value does not change. After the reaction is completed, 15 mL of absolute ethanol is added, and after suction filtration and water washing, the obtained oxidized cellulose is placed in a 250 mL cone Add 70mL of deionized water and 0.6g of sodium chlorite to a shaped bottle, adjust the pH value to 4-5 with glacial acetic acid, then magnetically stir at 70°C for 1 hour, filter with suction and wash with water to obtain carboxylated cellulose, and then reconstitute into 0.25% carboxylated cellulose aqueous solution, then mechanically dispersed by a high-speed mixer at 15,000 rpm for 4 minutes, 600 bar high-pressure homogeneous mechanical treatment for 5 times, and powerfully ultrasonicated for 30 minutes at a power of 320 W to obtain a nanocellulose aqueous solution;

2. Hybrid compounding of nanocellulose and inorganic nanoparticles: Take 100mL of nanocellulose aqueous solution with a concentration of 0.25% obtained in step 1, add 0.05g of nano-Al ₂ O ₃ with a particle size of 10nm and 0.05g of particle size Nano-TiO ₂ particles of 10nm were subjected to strong ultrasonic treatment for 30 minutes at a power of 800W to obtain a hybrid composite solution;

3. Composite of nanomaterials and water-based resin emulsion: ①. Add cationic surfactant to the hybrid compound liquid, and perform ultrasonic treatment for 30 minutes under the power of 300W to obtain the primary mixture; ②. Rotate the primary mixture, Until the remaining solution of the rotary steaming is 1/5 of the volume of the original mixture, the remaining solution of the rotary steaming is added to 167mL of water-based wood coatings, and the ultrasonic treatment is carried out under the power of 300W for 30min to obtain the mixed coating; ③. Stir and mix the coating at a high speed of 15,000 rpm for 30 minutes to obtain the nanocellulose hybrid inorganic nanoparticle modified water-based wood coating. Wherein, the mass ratio of the cationic surfactant described in step 1. and the nanocellulose in the hybrid composite liquid is 1:100; the cationic surfactant described in step 3. 1. is octadecyl trimethyl chloride Ammonium chloride; Step 3. The mass ratio of nanocellulose in the water-based wood coatings described in 2. in the water-based wood coating and the rotary steaming remaining solution is 100:0.5;

Step 3. The water-based wood coating described in 2. is water-based polyurethane acrylic resin coating, wherein said water-based polyurethane acrylic resin coating is made up of water-based polyurethane acrylic resin, deionized water and curing agent, and the solid content of said water-based polyurethane acrylic wood coating 30%, and 1% of the solid content of the curing agent in the waterborne polyurethane acrylic wood coating, and the curing agent is an acyl phosphorus oxide UV curing agent.

Fig. 3 is the TEM figure of nanocellulose in the nanocellulose aqueous solution obtained in step 1 of embodiment 2, and the fiber diameter of nanocellulose in the nanocellulose aqueous solution obtained in step 1 of embodiment 2 is shown by Fig. 3 to be in the range of 10nm-20nm , the length is several microns, and the aspect ratio is greater than 100, indicating that the nanocellulose in the aqueous nanocellulose solution obtained in step 1 of Example 2 has a fine and uniform structure and a large aspect ratio.

Fig. 4 is the SEM figure of the nano-cellulose hybrid inorganic nanoparticle modified water-based wood coating obtained in Example 2, and the nano-cellulose hybrid inorganic nano-particle modified water-based wood coating obtained by Fig. 4 presents uniform nanoparticles Dispersed on the cellulose film, indicating that nanocellulose as a carrier effectively solves the dispersion problem of inorganic nanoparticles.

The nanocellulose hybrid inorganic nanoparticle modified water-based wood coating obtained in Example 2 and the unmodified wood coating are applied to the surface of maple wood by spraying respectively with a spraying amount of 120g/m ² , and the UV light of 600W/cm After curing under light intensity for 5s, place it at room temperature for 72h to obtain the nanocellulose hybrid inorganic nanoparticle modified water-based wood coating film obtained in Example 2 and the unmodified wood coating film, and test the mechanics of the two paint films performance, gloss, UV aging resistance and bactericidal performance, the results show that the hardness of the nano-cellulose hybrid inorganic nanoparticle modified water-based wood coating film obtained in Example 2 has improved by 22.3% compared with the unmodified wood coating film %, the wear resistance increased by 49.7%, the scratch resistance increased by 25.1%, the impact toughness increased by 19.5%, the gloss was only reduced by 10.3%, the UV aging resistance time increased by nearly 1 times, and the surface of the paint film The mold load rate was reduced by more than 85%, indicating that this method can effectively improve the comprehensive performance of water-based wood coatings and endow them with bactericidal functions.

Claims (10)

1. the method for the nanometer particle-modified water-borne wood coating of nano-cellulose hybrid inorganic, it is characterised in that it is by following step Suddenly complete：

First, the preparation of nano-cellulose aqueous：Cellulosic material is stripped to processing, delignification processing successively and removes half fibre Dimension element processing, obtains purifying cellulose, carries out Biological Pretreatment to purifying cellulose, obtains nano-cellulose aqueous；

Described Biological Pretreatment refers to cellulase pretreatment, and concrete operations are as follows：Purifying cellulose is added to 250mL beaker In, it is 0.1%~0.3% to add deionized water to the mass fraction of purifying cellulose, cellulase is added, under the conditions of 50 DEG C 2h is pre-processed, then after 90 DEG C handle 2h, after being filtered by vacuum and washing, it is 0.1%~0.3% to be made into mass concentration again Cellulose aqueous, then the high-pressure homogeneous machinery processing 30min through 600bar, produce nano-cellulose aqueous；

Cellulosic material described in step 1 is that granularity is that more than 60 mesh wood powder, granularity is more than 60 mesh crops Stalk powder or waste and old paper；

2nd, the hybridization compounding of nano-cellulose and inorganic nano-particle：Added in the nano-cellulose aqueous obtained to step 1 Zero dimension inorganic nano-particle, in the case where power is 300W~1000W, ultrasonic wave strength is ultrasonically treated 30min~240min, obtains nothing Machine nano-particle and the dispersed hybridization compounding liquid of nano-cellulose；

3rd, nano material and resin aqueous emulsion are compound：1., by cationic surfactant add hybridization compounding liquid in, in work( Rate is that ultrasonic wave strength is ultrasonically treated 30min~240min under 300W~1000W, obtains just mixed thing；2., first mixed thing is revolved Steam, untill revolving surplus solution is originally mixed object product 1/5~1/2, revolving surplus solution is added to water-borne wood coating In, in the case where power is 300W~1000W, ultrasonic wave strength is ultrasonically treated 30min~240min, obtains compo；3., with height Fast mixer high-speed stirred compo 30min under 15000rpm speed, produce nano-cellulose hybrid inorganic nanoparticle Sub- modified water-soluble woodwork coating.

2. the method for the nanometer particle-modified water-borne wood coating of nano-cellulose hybrid inorganic according to claim 1, its The quality for the Biological Pretreatment process cellulase being characterised by described in step 1 and Nanowire in nano-cellulose aqueous Plain mass ratio is tieed up as 2:1.

3. the method for the nanometer particle-modified water-borne wood coating of nano-cellulose hybrid inorganic according to claim 1, its It is SiO to be characterised by the zero dimension inorganic nano-particle described in step 2₂、Al₂O₃、TiO₂, ZnO and CeO₂In any one or it is several The composition of kind.

4. the method for the nanometer particle-modified water-borne wood coating of nano-cellulose hybrid inorganic according to claim 1, its The particle diameter for the zero dimension inorganic nano-particle being characterised by described in step 2 is 10nm~30nm.

5. the method for the nanometer particle-modified water-borne wood coating of nano-cellulose hybrid inorganic according to claim 1, its It is characterised by nanofiber in the nano-cellulose aqueous that the zero dimension inorganic nano-particle described in step 2 obtains with step 1 The mass ratio of element is (1~5):10.

6. the method for the nanometer particle-modified water-borne wood coating of nano-cellulose hybrid inorganic according to claim 1, its It is cetyl trimethylammonium bromide, octadecyl trimethyl bromine to be characterised by the cationic surfactant described in step 3 Change any one or a few the combination in ammonium, hexadecyltrimethylammonium chloride or OTAC.

7. the method for the nanometer particle-modified water-borne wood coating of nano-cellulose hybrid inorganic according to claim 1, its It is water-soluble polyurethane acrylic resin coating or water-based acrylic resin to be characterised by the water-borne wood coating described in step 3 Coating.

8. the method for the nanometer particle-modified water-borne wood coating of nano-cellulose hybrid inorganic according to claim 7, its Water-soluble polyurethane acrylic resin coating described in being characterised by is by water-soluble polyurethane acrylic resin, deionized water and curing agent Composition, the solid content of the watersoluble polyurethane acrylic acid woodwork coating is 30%, and described watersoluble polyurethane acrylic acid woodenware applies The 0.5%~1% of the solid content of curing agent in material, described curing agent are amino resins class low-temperature self-crosslinking curing agent or acyl group Phosphorus oxidation species ultraviolet curable agent；Or described water soluble acrylic acid woodwork coating by water-based acrylic resin, deionized water and Curing agent forms, and the solid content of the water soluble acrylic acid woodwork coating is 30%, and in described water soluble acrylic acid woodwork coating The 0.5%~1% of the solid content of curing agent, described curing agent are amino resins class low-temperature self-crosslinking curing agent or acyl group phosphorus oxygen Compound class ultraviolet curable agent.

9. the method for the nanometer particle-modified water-borne wood coating of nano-cellulose hybrid inorganic according to claim 1, its The mass ratio of cationic surfactant and nano-cellulose in hybridization compounding liquid described in being characterised by step 3 1. is (0.5~1):100；Step 3 2. described in solid masses and nano-cellulose in revolving surplus solution in water-borne wood coating Mass ratio is 100:(0.2~0.8).

10. the method for the nanometer particle-modified water-borne wood coating of nano-cellulose hybrid inorganic, it is characterised in that it is by following What step was completed：

First, the preparation of nano-cellulose aqueous：Cellulosic material is stripped to processing, delignification processing successively and removes half fibre Dimension element processing, obtains purifying cellulose, carries out Chemical Pretreatment to purifying cellulose, obtains nano-cellulose aqueous；

Extracting processing described in step 1：It is put into after 3g cellulosic materials are wrapped with filter paper in 250mL Soxhlet extractors, so Add 240mL toluene-ethanos mixed solution afterwards and be used as extraction solvent, extract 10h at 90 DEG C in water-bath, remove extract into Point, obtain removing the wood powder for extracting composition；The volume ratio of toluene and ethanol is 2 in described toluene-ethano mixed solution:1；

Cellulosic material described in step 1 is the wood powder that granularity is 120 mesh；

Delignification processing described in step 1：1., by above-mentioned gained remove extracting composition wood powder be put into 500mL wide-mouths cone In shape bottle, the mixed solution of glacial acetic acid, sodium chlorite and deionized water, altogether 300mL, and being sealed with preservative film are added；Wherein, Glacial acetic acid is 0.2mL, and sodium chlorite 1g, remaining liquid is water；Then, the conical flask equipped with above-mentioned mixed solution is put In the magnetic force heating stirring 1h in 75 DEG C of waters bath with thermostatic control, mixed solution is obtained；2., into the mixed solution of gained according to first adding 0.2mL glacial acetic acid and 1g sodium chlorites, the magnetic force heating stirring 1h in 75 DEG C of waters bath with thermostatic control；3., repeat step 2. operate 4 It is secondary, it is filtered by vacuum with glass filter or Buchner funnel under 0.08MPa, and constantly washed with distilled water in filtered fluid is in Property, finally untill being filtered out without aqueous, delignification process is completed, obtains holocellulose；

Hemicellulose is gone to handle described in step 1：Above-mentioned gained holocellulose loading 500mL mass concentration has been used into In the wide mouthed Erlenmeyer bottle after 5% potassium hydroxide solution rinse, to pour into the potassium hydroxide solution that 300mL mass concentrations are 5%, Rim of a cup is sealed with preservative film, stands 12h at room temperature, so that the abundant swollen fiber of alkali lye；It is then placed in 90 DEG C of thermostat water baths Heating stirring 2h；After reaction terminates, it is filtered by vacuum with Buchner funnel or glass filter under 0.08MPa, and use distilled water Wash repeatedly to filtered fluid in neutrality, finally untill being filtered out without aqueous, hemicellulose process is gone in completion, obtains cleaning cellulose Element；

Chemical Pretreatment described in step 1 refers to TEMPO oxidation processes, and concrete operations are as follows：Purifying cellulose is loaded In 250mL beaker, it is 0.25% to add the mass fraction of deionized water extremely, sequentially adds 0.25g sodium bromides and 0.025g TEMPO, under magnetic agitation, 5mL mass concentrations are added as 12% liquor natrii hypochloritis using 2.5mL/min addition speed, then The sodium hydroxide for being 0.5mol/L using concentration regulation pH value is 10~10.5, and sustained response to pH value does not change, and terminates Reaction, adds 15mL absolute ethyl alcohol, 250mL conical flasks is placed in after filtering, washing, then by obtained oxycellulose In, 70mL deionized waters and 0.6g sodium chlorites are added, pH value is adjusted to 4~5 with glacial acetic acid, then in 70 DEG C of magnetic agitations 1h, filter, washing, obtain carboxylated cellulose element, be then made into 0.25% carboxylated cellulose element aqueous again, then pass through The high-pressure homogeneous machinery of 15000rpm homogenizer mechanical dispersion 4min, 600bar is handled 5 times, is strongly surpassed under 320W power Sound 30min, nano-cellulose aqueous is made；

2nd, the hybridization compounding of nano-cellulose and inorganic nano-particle：Take the nanofiber for 0.25% concentration that step 1 obtains Plain aqueous 100mL, it is charged with the nanometer Al that 0.05g particle diameters are 10nm₂O₃With the nano-TiO that 0.05g particle diameters are 10nm₂Grain Son, in the case where power is 800W, ultrasonic wave strength is ultrasonically treated 30min, obtains hybridization compounding liquid；

3rd, nano material and resin aqueous emulsion are compound：1., by cationic surfactant add hybridization compounding liquid in, in work( Rate is that ultrasonic wave strength is ultrasonically treated 30min under 300W, obtains just mixed thing；2., first mixed thing is rotated, it is remaining molten to rotating Liquid is added in 167mL water-borne wood coating untill originally mixing object product 1/5, will to rotate surplus solution, is in power Ultrasonic wave strength is ultrasonically treated 30min under 300W, obtains compo；3., with homogenizer under 15000rpm speed High-speed stirred compo 30min, produce the nanometer particle-modified water-borne wood coating of nano-cellulose hybrid inorganic；Wherein, walk Rapid three 1. described in cationic surfactant and hybridization compounding liquid in the mass ratio of nano-cellulose be 1:100；Step 3 1. cationic surfactant described in is OTAC；Step 3 2. described in water-borne wood coating The mass ratio of solid masses and nano-cellulose in revolving surplus solution is 100:0.5；

Step 3 2. described in water-borne wood coating be water-soluble polyurethane acrylic resin coating, wherein described water-based poly- ammonia Ester acrylic resin paint is made up of water-soluble polyurethane acrylic resin, deionized water and curing agent, the aqueous polyurethane third The solid content of olefin(e) acid woodwork coating is 30%, and the solid content of curing agent in described watersoluble polyurethane acrylic acid woodwork coating 1%, described curing agent is acyl group phosphorus oxidation species ultraviolet curable agent.