CN115651471A

CN115651471A - Water-based paint composition and preparation method thereof

Info

Publication number: CN115651471A
Application number: CN202110273160.3A
Authority: CN
Inventors: 李翠芝
Original assignee: Ningbo Gechuang New Material Technology Co ltd
Current assignee: Ningbo Gechuang New Material Technology Co ltd
Priority date: 2021-03-15
Filing date: 2021-03-15
Publication date: 2023-01-31

Abstract

The invention provides a water-based paint composition and a preparation method thereof, wherein the antibacterial paint composition comprises the following components: 10-15% of composite particles consisting of photocatalyst, adsorbent and antibacterial metal particles, 10-20% of resin, 3-6% of tackifier and the balance of solvent. The preparation method comprises the following steps of 1) preparing corresponding raw materials for preparing each component according to the component proportion in the water-based paint composition, wherein the components comprise composite particles, resin, a tackifier and solvent water; 2) Preparing the composite particles, specifically dissolving raw materials in the composite particles in a solvent, grinding and dispersing to obtain a dispersion liquid, and drying to obtain the composite particles; 3) Preparing the resin emulsion, wherein the particle size of the resin emulsion is 100-150nm, and the pH is 7.5-10; 4) Adding the composite particles, the resin emulsion, the tackifier and the solvent water into a container, mixing and stirring uniformly to obtain the water-based paint composition.

Description

Water-based paint composition and preparation method thereof

Technical Field

The invention relates to the technical field of coating compositions, in particular to a water-based coating composition with good stability and excellent antibacterial property and a preparation method thereof.

Background

Along with the continuous development of society, people have higher and higher requirements on health and safety, especially in the fields of food, medicine, home buildings and the like, pathogens such as bacteria, mold and the like attached to the surface of the material can cause great harm to human health, and can also cause decomposition, damage and deterioration of food, medicine and various building materials, thereby causing greater health and economic loss. Therefore, how to reduce or even avoid the harm of pathogens such as bacteria, mold and the like to the environment and human bodies becomes a problem which people want to solve.

The coating is a material which is used for the surfaces of various articles and buildings to play a role in decoration or play a specific role, and is widely applied to various fields relevant to life, such as the surfaces of medical appliances, personal electronic products, kitchen utensils, children toys, buildings and the like, so as to play a role in beautifying and protecting. However, these medical, food, daily necessities and buildings come into contact with people at any moment, and if the coatings on the surfaces of the medical, food, daily necessities and buildings do not have antibacterial capability, people are easily infected by bacteria and germs adhered to the surfaces of the coatings, so that the development of the coatings with excellent antibacterial performance has important significance.

With the continuous development of coating technology and the continuous research of people, antibacterial coatings have long-term progress, and most of the existing antibacterial agents are that organic antibacterial agents such as organic silicon quaternary ammonium salts and organic polyphenols and antibacterial metal ion compounds such as silver ions and tin ions are added into an antibacterial coating system together to endow a coating with antibacterial property. The antibacterial property imparted to the coating layer by such a physical addition method has a certain time-lapse property, and as time passes, antibacterial metal ions and the like are eluted and lost from the surface of the coating layer, and the antibacterial action is gradually lost. Therefore, the antibacterial agent is required to be uniformly dispersed in the coating, once the antibacterial agent with a high specific gravity is adopted, the antibacterial agent is easy to precipitate after the coating is formed by coating the coating, so that the antibacterial agent on the surface of the coating is relatively rare, the antibacterial agent is difficult to effectively dissolve out in the using process to play an antibacterial effect, and on the contrary, if the antibacterial agent with a low specific gravity is adopted, the antibacterial agent is enriched on the surface of the coating and the antibacterial agent on the bottom layer of the coating is rare, so that the antibacterial agent on the surface can be quickly dissolved out and released, and the antibacterial effect is difficult to stably and continuously play in the later period of the coating. In particular, the requirement for antibacterial timeliness is higher for personal electronic equipment such as kitchen appliances, mobile phones and computers, elevator keys and the like which are in close contact with the life of people in corresponding environments, or for facilities and articles such as bathroom appliances, medical appliances and the like which are frequently in contact with water and corrosive liquid.

Meanwhile, water-based coatings using water as a solvent are increasingly valued and popular for environmental and health needs over organic solvent coatings.

Therefore, the development of the water-based paint composition with good storage and use stability, beautiful appearance after coating and excellent antibacterial performance has important significance and wide application prospect.

Disclosure of Invention

The invention aims to provide a water-based paint composition which has good storage and use stability and excellent antibacterial performance.

In order to achieve the purpose, the invention adopts the following technical scheme:

1) Preparing corresponding raw materials for preparing each component according to the component proportion in the water-based coating composition, wherein the components comprise composite particles, resin, a tackifier and solvent water;

2) Preparing the composite particles, specifically dissolving raw materials in the composite particles in a solvent, grinding and dispersing to obtain a dispersion liquid, and drying to obtain the composite particles;

3) Preparing the resin emulsion, wherein the particle size of the resin emulsion is 100-150nm, and the pH is 7.5-10;

4) Adding the composite particles, the resin emulsion, the tackifier and the solvent water into a container, mixing and stirring uniformly to obtain the water-based paint composition.

Further preferably, the components comprise 10-15% of composite particles consisting of anatase titanium dioxide, hydroxyapatite and silver particles, 10-20% of resin, 3-6% of tackifier and the balance of solvent water.

Further preferably, 2) the composite particles are prepared by first preparing a dispersion of silver particles, and then adding anatase titanium dioxide and hydroxyapatite to the dispersion, followed by dispersion-grinding, and drying.

Further preferably, the preparation of the silver particle dispersion liquid is that the mixture of the silver stearate and the silver saccharin is dissolved in the ethylene glycol to be mixed, then the mixture is ground, dispersed and stirred uniformly, then the temperature is raised to 170-190 ℃, the mixture is heated for 5-20 minutes, then the methyl isobutyl ketone is added at room temperature, the mixture is continuously stirred and mixed uniformly, and after standing and layering, the ethylene glycol is removed.

Further preferably, the mass ratio of the silver stearate to the silver saccharin is 1.3-0.6.

Further preferably, the anatase titanium dioxide and the hydroxyapatite are added into the dispersion liquid for dispersion grinding under the condition of adding a polycarboxylic acid dispersant.

More preferably, in the composite particles, the content of anatase titanium dioxide is 55-60%, the content of hydroxyapatite is 30-35%, and the content of silver particles is 10-15%.

More preferably, the resin is acrylic resin, and the water absorption rate of the resin is 2-10%.

Further preferably, the tackifier is cyclodextrin, hydroxypropyl methylcellulose and ethyl cellulose, and the mass ratio of the cyclodextrin to the hydroxypropyl methylcellulose to the ethyl cellulose is 1.

The invention also provides a water-based paint composition prepared by the water-based paint preparation method and an antibacterial coating prepared from the water-based paint composition.

The water-based paint composition and the antibacterial coating prepared from the water-based paint composition adopt composite particles composed of specific particle sizes and proportions, combine unique resin and tackifier, adopt environment-friendly and nontoxic water as a solvent, and combine a specific preparation process, so that the excellent storage performance of the paint composition in a micro-particle size state is realized, the use stability and economic and environment-friendly performance of the paint composition are ensured, and the coating formed after coating has excellent appearance transparency and lasting antibacterial and bacteriostatic properties.

Detailed Description

Example 1

Firstly, determining the component proportion of the water-based paint composition and preparing corresponding component raw materials. Wherein, the mass percentage of the composite particles is 13 percent, the mass percentage of the resin is 15 percent (calculated by solid content), the mass percentage of the tackifier is 5 percent, and the rest is the solvent; the composite particles comprise 57% of photocatalyst, 32% of adsorbent and 11% of antibacterial metal particles by mass percentage, wherein the photocatalyst is anatase titanium dioxide (60 nm), the adsorbent is hydroxyapatite (80 nm), and the antibacterial metal particles are a mixture (100 nm) of silver stearate and silver saccharin. Specifically, the composite particles are prepared by mixing 5% by mass of silver stearate, 2% by mass of silver saccharin and 93% by mass of ethylene glycol, then placing the mixture into a container containing zirconia beads (phi 0.3 mm), grinding, dispersing and stirring the mixture uniformly, then heating the dispersion to 185 ℃ for 10 minutes while stirring, then adding methyl isobutyl ketone accounting for 20% of the mass of the ethylene glycol at room temperature, continuously stirring and mixing the mixture uniformly, standing the mixture for 1 hour, and removing the ethylene glycol after layering, thereby obtaining a dispersion containing silver particles; subsequently, a photocatalyst and an adsorbent were added to the dispersion, and a polycarboxylic acid dispersant was added in an amount of 1.5% relative to the total amount of the composite particles, and the mixture was further subjected to milling dispersion in a zirconia bead container for 2 hours and then dried to obtain composite particles having a D50 of 70nm and a D90/D50 of 1.1. Specifically, the resin is prepared by selecting 15% of styrene, 35% of methyl methacrylate, 25% of butyl acrylate, 15% of 2-ethylhexyl acrylate, 2% of diacetone acrylamide, 2% of 2-hydroxyethyl acrylate, 0.5% of acrylic acid and 5.5% of polyvinyl alcohol surfactant in percentage by mass, and adding the materials into 35 parts of deionized water based on 100 parts of the total mass of the materials to mix so as to obtain a pre-emulsion; selecting 2.5% ammonium persulfate water solution as initiator solution; under the conditions of heating at 90 ℃ and nitrogen protection, firstly adding 5% of pre-emulsion and initiator solution with equal mass into 20 parts of deionized water based on 100 parts of the total mass of the pre-emulsion in a reaction container, and continuously dropwise adding the rest of pre-emulsion and 10 parts of initiator solution based on 100 parts of the total mass of the pre-emulsion into the reaction container within 3 hours after 20 minutes; after the dropwise addition, the temperature is kept for 1.5 hours, then the temperature is reduced to 50 ℃, and the pH value and the solid content of the emulsion are adjusted by ammonia water, so that the resin emulsion has the pH =8.5, the particle size of 120nm and the water absorption of 8%. The tackifier is cyclodextrin, hydroxypropyl methylcellulose and ethyl cellulose, and the mass ratio of the cyclodextrin to the hydroxypropyl methylcellulose to the ethyl cellulose is 1. The solvent is deionized water. Adding the composite particles, the resin emulsion, the tackifier and the solvent into a container, mixing and stirring uniformly to obtain the water-based paint composition.

In example 2, the contents of the respective components in the coating composition were adjusted to 20% by weight of the composite particles, 15% by weight of the resin (in terms of solid content), 5% by weight of the tackifier and the balance of the solvent, and the remainder was the same as in example 1.

In example 3, the contents of the respective components in the coating composition were adjusted to 8% by weight of the composite particles, 22% by weight of the resin (in terms of solid content), 4% by weight of the tackifier and the balance of the solvent, and the remainder was the same as in example 1.

In examples 4 to 5, only cyclodextrin or hydroxypropylmethylcellulose and ethylcellulose were selected as the tackifier, respectively, and the rest was the same as in example 1.

In example 6, the heating temperature in ethylene glycol in the silver particle preparation step was adjusted to 150 ℃, and the rest was the same as in example 1.

In example 7, the same procedure as in example 1 was repeated except that anatase type titanium dioxide and hydroxyapatite were added to the dispersion liquid to perform dispersion grinding, and a polycarboxylic acid dispersant was added in an amount of 1% of the total amount of the composite particles.

In example 8, silver stearate alone and no silver saccharin was used for the silver particles, which were otherwise the same as in example 1.

In example 9, the resin was allowed to absorb 20% of water by adjusting the ratio of each component in the resin emulsion, and the rest was the same as in example 1.

The coating compositions of the above examples were applied to the surface of a transparent ABS resin plate by an air spray process to form a coating layer (except example 9) having a thickness of 20 μm, followed by drying at room temperature and a relative humidity of 60% for a period of one week, and then performance tests were performed on the respective coating layers, and the results are shown in table 1, in which:

(1) Test for antibacterial Property

Coating bacteria liquid on the surface of the antibacterial coating, culturing for 24 +/-1 hours at 35 +/-1 ℃ under the condition that the relative humidity is not less than 90 percent, washing the bacteria liquid, and measuring the surface 1cm of the antibacterial coating ² The number of bacteria in the region was determined using Escherichia coli (ATCC 8739). The specific antibacterial performance was evaluated by assuming that a = A1-A2 is used when the logarithmic value of the number of bacteria after cultivation on the surface of the substrate without the antibacterial coating layer is A1 and the logarithmic value of the number of bacteria after cultivation on the surface of the substrate with the antibacterial coating layer is A2The antibacterial performance of the antibacterial coating was evaluated.

(2) Stability testing

After the antibacterial coating composition of the present invention was placed in a closed container and stored at 40 ℃ for 30 days, the coating composition liquid was observed and handled, and it was excellent that there was no precipitate at all in the liquid (. Smallcircle.), it was fair that there was little precipitate in the liquid and the precipitate disappeared after stirring (DELTA.), and poor that there was much precipitate in the liquid (X).

(3) Appearance Property test

The haze value of the surface of the antibacterial coating is tested by adopting an HZ-V3 type haze meter, and the lower the haze value is, the better the transparency of the coating is, and the better the corresponding appearance visual effect is.

(4) Deodorization Performance test

Respectively placing the product with the surface of 20cm multiplied by 20cm coated with the antibacterial coating and the product without the antibacterial coating in a closed space, simultaneously injecting mixed gas of ammonia gas and nitrogen gas with the ammonia gas concentration of 100ppm, and measuring the ammonia gas concentration again after placing for 24 h. The specific deodorizing performance was evaluated such that C% = (C1-C2)/C1 × 100 was used to evaluate the deodorizing performance of the antibacterial coating, where C1 represents the measured concentration of the product not coated with the antibacterial coating and C2 represents the measured concentration of the product coated with the antibacterial coating.

TABLE 1

	1	2	3	4	5	6	7	8	9
										Antibacterial property	5.3	5.1	4.1	4.7	5.0	4.5	4.8	5.0	4.4
Stability of	○	×	○	×	△	×	△	○	△
										Appearance of the product	7.5	15	9.9	23	20	40	28	7.1	8.2
Deodorizing property	92	90	86	89	82	87	89	90	87

The following further illustrates the formulation of the antimicrobial coating composition system of the present invention:

the photocatalyst in the antibacterial coating material of the present invention is a substance that exhibits a photocatalytic effect by absorbing ultraviolet rays, visible light, and the like, and decomposes organic substances, bacteria, and the like adsorbed on the surface of the adsorbent by the reduction and oxidation respectively exerted by excited electrons and holes generated in the photocatalyst by the absorption of light. Among them, anatase titanium dioxide is preferable as the photocatalyst, and it is preferable from the viewpoint of safety, economy and the like. The content of the components should be at least 55% of the composite particles for their effects, but the content should be controlled to be less than 60% in order to ensure the content of other components for the overall efficacy of the composite particles.

The adsorbent in the antibacterial coating is used for adsorbing bacteria, organic matters and the like on the surface of the antibacterial coating, so that the adsorbed bacteria, organic matters and the like can be decomposed or killed by the photocatalyst and the antibacterial metal particles. The adsorbent is preferably hydroxyapatite, the content of the hydroxyapatite in the composite particles is preferably 30-35%, too low content of the hydroxyapatite cannot effectively exert the adsorption effect, but too high content of the hydroxyapatite can influence the decomposition and killing of bacteria.

The antibacterial metal particles in the antibacterial coating can exert excellent bactericidal and antibacterial effects when contacting with bacteria, metal monomers, metal ions, or precursors such as metal salts and metal oxides which generate the metal monomers and the metal ions can be used, wherein the metal monomers are preferred, silver particles with the optimal comprehensive performance of economy and bactericidal performance are particularly preferred, the silver particles account for 10-15% of the composite particles, if the content of the silver particles is too low, the algae prevention, mildew prevention and bactericidal antibacterial performance is insufficient, if the content of the silver particles is too high, the appearance performance of the coating is influenced due to the coloring performance caused by the silver particles, and meanwhile, the excessive silver particles can obviously inhibit the light absorption and catalytic effects of the photocatalyst. In particular, in order to satisfy the requirement of the overall particle size distribution of the composite particles, the particle size of the silver particles should not be excessively large, preferably 100nm or less, but this poses a great challenge to the uniform dispersibility of the silver particles, and in order to avoid the agglomeration of the silver particles to obtain fine 100nm uniformly dispersed silver particles, the present invention first performs the preparation of the silver particles in the preparation of the composite particles, and first heats the silver stearate in an ethylene glycol solvent having a relatively high boiling point at a high temperature so that the solvent does not volatilize and the silver stearate is easily dissolved by the high temperature heating, and is also easily reduced after the dissolution to obtain ultra-fine silver particles whose surfaces are modified with fatty acid, in order to ensure the ultra-fine silver particles, the heating temperature should be at least 170 ℃ but should not be too high, for example, 190 ℃, which may result in too fast volatilization of the ethylene glycol and also in massive decomposition of the silver stearate to obtain ultrafine particles with surface modified by fatty acid, thereby avoiding direct contact between the silver and the resin to reduce the possibility of resin decomposition, thereby ensuring formability, and then extracting ultrafine silver particles into methyl isobutyl ketone by using methyl isobutyl ketone with lower boiling point, which can be separated from the ethylene glycol, as a solvent, while reaction by-products such as stearic acid remain in the ethylene glycol and can be removed together with the ethylene glycol, thereby obtaining a uniformly dispersed ultrafine silver particle dispersion. In addition, a certain amount of saccharin silver and silver stearate are selected together, so that the dissolution performance of silver ions after a coating is formed subsequently can be promoted, the antibacterial property of the coating is obviously improved, in order to exert the effect of the saccharin silver, the saccharin silver is more than 0.3 part relative to 1 part of the silver stearate, but the content of the saccharin silver is not more than 0.6 part, otherwise, excessive components which are not needed for forming silver particles are introduced, the cost is increased, and the transparency performance of the coating is obviously reduced.

The content of the composite particles in the antibacterial coating is preferably 10-15% of the content of the antibacterial coating, and if the content is too low, the antibacterial coating cannot exert sufficient and effective antibacterial performance, but if the content is too high, the surface of the coating is uneven, so that the appearance is affected, and the antibacterial performance is reduced. Meanwhile, the D50 of the composite particles is preferably 50 to 80nm because if the D50 exceeds 80nm, the storage stability of the coating composition is difficult to satisfy and the dispersibility in the coating layer is not ensured to result in a decrease in both the transparency and the antibacterial property of the coating layer, but the D50 is not so small, otherwise the technical requirements for the dispersion of fine particles are too high, agglomeration is liable to occur, and it is disadvantageous for economy. Further, the D90/D50 of the composite particles is preferably less than 1.2, because a D90/D50 exceeding 1.2 means that the particle size distribution range of the composite particles is too large, more coarse particles will be present in the coating layer, and the dispersibility of the composite particles in the coating layer is not uniform, thereby seriously reducing the transparency and antibacterial property of the coating layer.

The resin in the antibacterial coating material of the present invention is preferably an acrylic resin having a carboxyl group from the viewpoint of the storage property of the coating composition and the antibacterial property of the formed coating layer. Meanwhile, the water absorption of the acrylic resin should be in the range of 2-10% (the water absorption is calculated by dissolving and coating the resin with a solvent of 10% relative to the solid content of the resin for 30 μm, drying the resin for one week at room temperature and 60% relative humidity to obtain a coating, then soaking the coating in deionized water at room temperature for 24 hours, weighing the weight, and determining the weight percentage of the weight increase to be the water absorption), if the water absorption exceeds 10%, the durability, antibacterial property and the like of the formed coating are seriously reduced, and certainly, the water absorption should not be too low, otherwise, on one hand, the preparation difficulty and the cost are increased, and on the other hand, the dissolution of metal ions is not facilitated to generate the antibacterial effect. Further, in order to secure storage stability of the coating composition, the particle diameter of the resin is preferably 100 to 150nm, and the range of pH =7.5 to 10 is most preferable.

The tackifier in the invention is selected from cyclodextrin, hydroxypropyl methylcellulose and ethyl cellulose. The cyclodextrin has a cyclic part and a branch part simultaneously, has no peculiar smell such as sweet taste and the like commonly existing in starch tackifiers, and is easy to digest and absorb by human bodies, so the cyclodextrin is safe, nontoxic and tasteless for coatings firstly, has concentrated molecular weight distribution, narrow distribution range and high solubility in water, and is even easy to dissolve in cold water, and the cyclodextrin serving as the tackifier can enable the coating to be easy and convenient to coat; in addition, the cyclodextrin has good stability under the environment conditions of acidity and salt, is not easy to age and has moderate viscosity, and is very suitable to be used as a tackifier of the coating composition; meanwhile, the cyclodextrin is a macromolecule, and the molecular weight distribution of the cyclodextrin is concentrated, so that the osmotic pressure cannot be increased, and the stability of the coating is good and the coating cannot absorb water too quickly; particularly, the cyclodextrin ring structure is internally provided with holes capable of accommodating small molecules, and the hydroxyl of the cyclodextrin is positioned outside the holes, so that the holes are hydrophobic, can be coated with substances which are easy to react with water and oxygen to play a role in protection, and can be used as a supplement of an adsorbent to capture odor molecules so as to strengthen the effects of deodorizing. On one hand, the hydroxypropyl methyl cellulose can play a main role in gelatinization and bonding to form a suspension without precipitation, so that the coating composition has excellent dispersibility and stability; on one hand, the coating can be matched with ethyl cellulose in a synergistic manner, so that the coating plays a good supporting role on the ethyl cellulose, and the shape and the appearance of the coating can be well maintained when the coating is formed; in addition, due to good water solubility, the coating can be dissolved by moisture in the environment for a long time in the using process after the coating is formed, so that holes are formed in the coating, and the odor can be better and continuously removed. The use of ethyl cellulose together with hydroxypropylmethyl cellulose ensures the robustness of the coating formation. In order to exert the synergistic advantages of the three, the ratio of the three is preferably 1.

In addition, the coating thickness of the coating composition is preferably 10 to 60 μm, and an excessively thick coating thickness may result in a decrease in transparency of the coating layer to affect the appearance, may also easily cause unevenness in coating to affect the appearance, and may be difficult to uniformly coat particularly when the substrate has irregularities; the coating should not be too thin, which on the one hand requires too high a coating process and increases costs, and on the other hand too thin a coating is prone to premature failure.

In conclusion, the water-based paint composition adopts composite particles formed by specific particle sizes and proportions, combines unique resin and tackifier, adopts environment-friendly and nontoxic water as a solvent and is assisted by a specific preparation method, so that the excellent storage performance of the antibacterial paint composition is realized, the use stability and economic and environment-friendly performance of the paint composition are ensured, and a coating formed after coating has excellent appearance transparency and lasting antibacterial and bacteriostatic performance.

Although the present invention is illustrated by the above examples for the effect of the coating material of the present invention, the present invention is not limited to the above examples. It should be understood by those skilled in the art that any modification of the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.

Claims

1. A method of preparing an aqueous coating composition, comprising the steps of:

2. The method of claim 1, wherein: the components comprise 10-15% of composite particles consisting of anatase titanium dioxide, hydroxyapatite and silver particles, 10-20% of resin, 3-6% of tackifier and the balance of solvent water.

3. The method of claim 2, wherein: 2) The composite particles are prepared by preparing a dispersion of silver particles, adding anatase titanium dioxide and hydroxyapatite into the dispersion, dispersing, grinding and drying.

4. The production method according to claim 3, characterized in that: the preparation method of the silver particle dispersion comprises the steps of firstly dissolving a mixture of silver stearate and silver saccharin in ethylene glycol, mixing, grinding, dispersing and stirring uniformly, then heating to 170-190 ℃ for 5-20 minutes, then adding methyl isobutyl ketone at room temperature, continuously stirring and mixing uniformly, standing for layering, and removing the ethylene glycol.

5. The method of claim 4, wherein: the mass ratio of the silver stearate to the silver saccharin is 1.3-0.6.

6. The production method according to any one of claims 3 to 5, characterized in that: the anatase titanium dioxide and the hydroxyapatite are added into the dispersion liquid for dispersion grinding under the condition of adding a polycarboxylic acid dispersant.

7. The method of claim 2, wherein: in the composite particles, the content of anatase titanium dioxide is 55-60%, the content of hydroxyapatite is 30-35%, and the content of silver particles is 10-15%.

8. The method of claim 1, wherein: the resin is acrylic resin, and the water absorption rate of the resin is 2-10%.

9. The method of claim 1, wherein: the tackifier is cyclodextrin, hydroxypropyl methylcellulose and ethyl cellulose, and the mass ratio of the cyclodextrin to the hydroxypropyl methylcellulose to the ethyl cellulose is 1.

10. An aqueous coating composition prepared by the method of any one of claims 1 to 9.