Multicolor real stone paint for coating and preparation method thereof

Abstract

The application discloses a multi-color real stone paint for coating and a preparation method thereof, and relates to the technical field of building coating. The multi-color real stone paint comprises a composite cellulose system compounded by component A and component B. The molecular weight of component A is 20,000-40,000, and the viscosity of a 2% water solution is 100-500 mPa·s. The molecular weight of component B is 100,000-150,000, the viscosity of a 2% water solution is 3,000-8,000 mPa·s, and component B is modified by a long-chain hydrophobic alkyl group with C12-C18. The weight ratio of component A to component B is 1:1-1:2.5. The preparation method comprises the following steps: preparing a base paint containing component A and component B under the condition of pH 9.0-10.0; granulating the base paint to form color particles; slowly reducing the pH of the system to 7.5-8.5 to trigger the formation of a hydrophobic association network of component B; and adding a continuous phase and uniformly stirring. The application realizes the precise regulation of the viscosity in the three stages of granulation, storage and construction through the composite cellulose system and the pH gradient release process.

Description

Technical Field

[0001] This invention relates to the field of architectural coatings technology, and more specifically to a multicolored stone-like paint for coatings and its preparation method. Background Technology

[0002] Multi-colored stone-like paint is widely used in exterior wall decoration due to its decorative effect that mimics natural stone. In existing technologies, multi-colored stone-like paint typically adopts a technical system of "base paint + granulation liquid + continuous phase," in which cellulose ether thickeners play a key role in thickening, protecting, and stabilizing the multi-colored particles.

[0003] Chinese patent application number 201210156035.5 discloses a method for preparing an environmentally friendly water-based multicolor coating. This method includes steps of preparing a granulating colloidal solution, preparing color particles, and preparing the finished paint. While this technology has advantages such as simple preparation and stable quality, the multicolor coating prepared by it has significant viscosity control problems in practical applications: a lower viscosity is required during the granulation stage to facilitate particle formation, a higher viscosity is required during storage to prevent sedimentation, and appropriate rheological properties are needed during the application stage to ensure the spraying effect. Single-component cellulose cannot simultaneously meet the viscosity requirements of multiple stages.

[0004] Another prior art publication, CN114752270A, discloses a multi-colored lightweight stone-like paint coating. It adds hydroxyethyl cellulose to a tinted base paint, utilizing the cross-linking reaction between cellulose and the emulsion to improve the strength of the colored particles. While this technology addresses the role of cellulose, it employs a single cellulose system, which is prone to post-thickening during actual storage—the continuous reaction between cellulose and the protective colloid (lithium magnesium silicate) leads to an abnormal increase in viscosity, ultimately affecting application performance and even causing gel spoilage. Furthermore, this technology does not consider the differentiated viscosity requirements at different stages, creating a contradiction in viscosity control between the granulation and storage stages.

[0005] Industry analysis indicates that the issue of blooming during the application of stone-like paint is the biggest source of quality complaints, and this blooming phenomenon is closely related to the rheological properties of the coating. When using single cellulose, "sticking to the trowel" or "sand flying" phenomena easily occur during spraying. The main reason for these problems is that current technology has failed to achieve differentiated release of cellulose during granulation, storage, and application, resulting in insufficient precision in viscosity control.

[0006] Therefore, it is necessary to propose a multicolored stone-like paint for coatings and its preparation method to solve the above problems. Summary of the Invention

[0007] The purpose of this invention is to solve the problems in the prior art where single cellulose cannot simultaneously meet the viscosity requirements of multiple stages such as granulation, storage, and construction, and the thickening during storage is difficult to control.

[0008] To achieve the above objectives, the present invention specifically adopts the following technical solution:

[0009] A multi-colored stone-like paint for coatings comprises a composite cellulose system, wherein the composite cellulose is composed of low molecular weight hydroxyethyl cellulose of component A and high molecular weight hydrophobic modified hydroxyethyl cellulose of component B, wherein the molecular weight of component A is 20,000 to 40,000 and the viscosity of a 2% aqueous solution is 100 mPa·s to 500 mPa·s.

[0010] The molecular weight of component B is 100,000 to 150,000, the viscosity of a 2% aqueous solution is 3,000 mPa·s to 8,000 mPa·s, and it is modified with C12 to C18 long-chain hydrophobic alkyl groups.

[0011] Furthermore, the weight ratio of component A to component B is 1:1 to 1:2.5.

[0012] Furthermore, the preparation process of the multicolored stone paint involves a gradient release process in which the pH is adjusted from 9.0 to 10.0 to 7.5 to 8.5.

[0013] Furthermore, the pH reduction process uses organic acids for slow adjustment, with the pH decrease rate controlled to no more than 0.2 per minute.

[0014] Further, by weight, it comprises the following components: 40 to 60 parts of base paint, 30 to 50 parts of granulation liquid, and 10 to 20 parts of continuous phase.

[0015] Furthermore, the base paint comprises, by weight:

[0016] Water: 20 to 30 parts;

[0017] Component A: 0.2 to 0.4 parts;

[0018] Component B: 0.3 to 0.5 parts;

[0019] Multifunctional pH adjuster: 0.1 to 0.2 parts;

[0020] Dispersant: 0.3 to 0.6 parts;

[0021] Wetting agent: 0.1 to 0.2 parts;

[0022] Titanium dioxide: 2 to 5 parts;

[0023] Calcined kaolin: 5 to 10 parts;

[0024] Triple calcium: 10 to 15 parts;

[0025] Colored sand: 40 to 50 parts;

[0026] Pure acrylic emulsion: 15 to 20 parts;

[0027] Film-forming aid: 0.8 to 1.5 parts;

[0028] Fungicide: 0.1 to 0.2 parts.

[0029] Further, the granulation solution comprises, by weight: water: 94 to 97 parts, lithium magnesium silicate: 3 to 5 parts, and preservative: 0.1 to 0.2 parts.

[0030] A method for preparing the above-mentioned multicolor stone-like paint includes the following steps:

[0031] Step 1: Prepare a base paint containing component A and component B under pH conditions of 9.0 to 10.0;

[0032] Step 2: Granulate the base paint obtained in Step 1 to form colored particles;

[0033] Step 3: Slowly lower the pH of the system to 7.5 to 8.5 to trigger the formation of the hydrophobic association network of component B;

[0034] Step 4: Add the continuous phase and stir until well mixed.

[0035] Furthermore, in the third step, a 10% citric acid aqueous solution is used to adjust the pH by adding it dropwise, with the drop rate controlled so that the pH decreases by no more than 0.2 every 10 minutes.

[0036] Furthermore, the specific operation for preparing the base paint in the first step is as follows: add water to the dispersion tank and start stirring;

[0037] Slowly add component A and component B, stirring until no obvious lumps remain;

[0038] Add a multi-functional pH adjuster to adjust the pH to 9.0 to 10.0, and continue stirring until the cellulose is completely dissolved;

[0039] Add the dispersant, wetting agent, and bactericide in sequence, and stir until well mixed;

[0040] Add titanium dioxide, calcined kaolin, and heavy calcium carbonate, and disperse at high speed until the fineness is less than or equal to 60μm;

[0041] Reduce the rotation speed, add colored sand, pure acrylic emulsion, and film-forming aid, and stir evenly.

[0042] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0043] 1. This invention enables precise viscosity control. During the granulation stage, the system viscosity is controlled between 800 mPa·s and 1200 mPa·s, with regular particle morphology and controllable size; during the storage stage, the viscosity gradually increases to 2500 mPa·s to 3500 mPa·s, with stable colored sand suspension and no hard sediment; during the construction stage, the viscosity drops to 500 mPa·s to 800 mPa·s under high shear, resulting in good atomization.

[0044] 2. The storage stability of this invention is significantly improved. After 30 days of heat storage at 50°C, the viscosity change rate is less than 15%, eliminating the risk of gelation caused by post-thickening.

[0045] 3. The invention improves construction performance. The flying sand rate is reduced by more than 40%, there are no obvious marks at the joints, and the integrity rate of colored dots is greater than 95%. Detailed Implementation

[0046] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0047] Preparation Example 1: Preparation of pH Adjuster Premix Solution

[0048] Weigh 50 grams of citric acid, add it to 450 grams of deionized water, stir to dissolve, and prepare a 10% citric acid aqueous solution for later use.

[0049] Preparation Example 2: Preparation of Granulation Solution

[0050] Weigh 4 kg of lithium magnesium silicate, add it to 96 kg of deionized water, disperse it at high speed for 30 minutes (dispersion speed 1100 rpm), and let it stand for hydration for 24 hours to obtain the granulation solution.

[0051] Example 1

[0052] This embodiment provides a multi-colored stone-like paint for coatings and its preparation method.

[0053] Base paint formulation (parts by weight):

[0054] 25 parts water

[0055] Component A (low molecular weight hydroxyethyl cellulose, molecular weight 30,000, 2% viscosity 300 mPa·s) 0.3 parts

[0056] Component B (high molecular weight hydrophobically modified hydroxyethyl cellulose, molecular weight 120,000, 2% viscosity 5000 mPa·s, hydrophobic)

[0057] 0.4 parts of modified long-chain C14

[0058] AMP-95 (Multifunctional pH Adjuster) 0.15 parts

[0059] Dispersant 5040 0.4 parts

[0060] Wetting agent X-405 0.15 parts

[0061] 0.15 parts of fungicide LXE

[0062] Titanium dioxide R-996 3 parts

[0063] 8 parts of calcined kaolin

[0064] 12 portions of triple calcium carbonate (800 mesh)

[0065] 45 parts colored sand (mixed from 40 to 80 mesh)

[0066] Pure acrylic emulsion RS-998A, 18 parts

[0067] 1.2 parts of alcohol ester twelve (film-forming aid)

[0068] The preparation method includes the following steps:

[0069] Step 1: Preparation of base paint

[0070] Add 25 parts water to a dispersion tank and start stirring at 700 rpm. Slowly add 0.3 parts component A and 0.4 parts component B, stirring for 12 minutes until no obvious lumps remain. Add 0.15 parts AMP-95 to adjust the pH to 9.5, and continue stirring for 20 minutes until the cellulose is completely dissolved and the system becomes transparent and viscous. Add 0.4 parts dispersant, 0.15 parts wetting agent, and 0.15 parts bactericide in sequence, and stir evenly. Add 3 parts titanium dioxide, 8 parts calcined kaolin, and 12 parts heavy calcium carbonate, and disperse at high speed for 25 minutes at 1350 rpm until the fineness is less than 60 μm. Reduce the speed to 700 rpm, add 45 parts colored sand, 18 parts pure acrylic emulsion, and 1.2 parts film-forming aid, and stir evenly to obtain the base paint.

[0071] Step 2: Granulation

[0072] The base paint obtained in the first step is injected into the granulation liquid obtained in Preparation Example 2 through a granulator according to the desired color to form colored particles, and then allowed to stand and harden for 3 hours.

[0073] Step 3: pH Adjustment and Paint Mixing

[0074] The hardened colored particles and granulation solution were transferred to a paint mixing tank, and a low-speed stirrer was started at 350 rpm. A 10% citric acid aqueous solution from Preparation Example 1 was slowly added dropwise, controlling the pH decrease rate to approximately 0.15 per minute, until the system pH reached 8.0. A continuous phase emulsion (pure acrylic emulsion RS-998A, 5 parts) was added, stirred until homogeneous, filtered, and packaged to obtain the multicolored stone paint.

[0075] Example 2

[0076] This embodiment provides a multi-colored stone-like paint for coatings and its preparation method.

[0077] Base paint formulation (parts by weight):

[0078] 28 parts water

[0079] Component A (low molecular weight hydroxyethyl cellulose, molecular weight 25,000, 2% viscosity 200 mPa·s) 0.2 parts

[0080] Component B (high molecular weight hydrophobically modified hydroxyethyl cellulose, molecular weight 110,000, 2% viscosity 4000 mPa·s, hydrophobically modified long-chain C12) 0.5 parts

[0081] AMP-95 0.18 copies

[0082] Dispersant 5040 0.5 parts

[0083] Wetting agent X-405 0.18 parts

[0084] 0.18 parts of fungicide LXE

[0085] 4 parts of titanium dioxide R-996

[0086] 7 parts of calcined kaolin

[0087] 13 portions of triple calcium carbonate (800 mesh)

[0088] 42 parts colored sand (mixed from 40 to 80 mesh)

[0089] Pure acrylic emulsion RS-998A, 17 parts

[0090] 1.0 part of alcohol ester twelve

[0091] The preparation method is basically the same as in Example 1, except that the pH is adjusted to 9.8 in the first step and then adjusted back to 7.8 in the third step.

[0092] Example 3

[0093] This embodiment provides a multi-colored stone-like paint for coatings and its preparation method.

[0094] Base paint formulation (parts by weight):

[0095] 22 parts water

[0096] Component A (low molecular weight hydroxyethyl cellulose, molecular weight 35,000, 2% viscosity 400 mPa·s) 0.4 parts

[0097] Component B (high molecular weight hydrophobically modified hydroxyethyl cellulose, molecular weight 130,000, 2% viscosity 6000 mPa·s, hydrophobically modified long-chain C16) 0.3 parts

[0098] AMP-95 0.12 copies

[0099] Dispersant 5040 0.6 parts

[0100] Wetting agent X-405 0.12 parts

[0101] 0.12 parts of fungicide LXE

[0102] Titanium dioxide R-996 5 parts

[0103] 9 parts of calcined kaolin

[0104] 11 parts of triple calcium carbonate (800 mesh)

[0105] 48 parts colored sand (mixed from 40 to 80 mesh)

[0106] Pure acrylic emulsion RS-998A, 19 parts

[0107] 1.4 parts of alcohol ester twelve

[0108] The preparation method is basically the same as in Example 1, except that the pH is adjusted to 9.2 in the first step and then adjusted back to 8.2 in the third step.

[0109] Comparative Example 1

[0110] This comparative example provides a multi-colored stone paint, whose base paint formula is basically the same as that of Example 1, except that: component A and component B are replaced with an equal amount (0.7 parts) of single high molecular weight hydroxyethyl cellulose (molecular weight 120,000, 2% viscosity 5000 mPa·s).

[0111] The preparation method is basically the same as in Example 1, except that the pH adjustment step is not performed and the pH of the system is maintained at 9.5.

[0112] Comparative Example 2

[0113] This comparative example provides a multi-colored stone paint, whose base paint formula is basically the same as that of Example 1, except that: component A and component B are replaced with an equal amount (0.7 parts) of single low molecular weight hydroxyethyl cellulose (molecular weight 30,000, 2% viscosity 300 mPa·s).

[0114] The preparation method is basically the same as in Example 1, except that the pH adjustment step is not performed and the pH of the system is maintained at 9.5.

[0115] Comparative Example 3

[0116] This comparative example provides a multi-colored stone paint with the same base paint formula and preparation method as Example 1. The difference is that the third step of pH adjustment involves adding 10% citric acid aqueous solution in one go, which lowers the pH from 9.5 to 8.0 within 1 minute.

[0117] Comparative Example 4

[0118] This comparative example refers to the formulation of Example 1 in Publication No. CN114752270A for the preparation of multicolored stone paint.

[0119] Performance testing

[0120] The performance of the multi-colored stone paints prepared in Examples 1 to 3 and Comparative Examples 1 to 4 was tested using the following methods:

[0121] Initial viscosity: determined at 25°C using a Forecast cup according to GB / T2794 method.

[0122] Thermal storage stability: The sample was stored in a 50℃ constant temperature chamber for 30 days. The viscosity after thermal storage was determined according to GB / T6753.3, and the viscosity change rate was calculated. Viscosity change rate = (Viscosity after thermal storage - Initial viscosity) / Initial viscosity × 100%.

[0123] Colored sand settling: Let the sample stand for 30 days and observe whether there is any hard sediment at the bottom of the container.

[0124] Flying sand rate: Under standard spraying conditions (spraying air pressure 0.7MPa, nozzle diameter 4.5mm), spray paint per unit area (1m²), collect the scattered colored dots, weigh them, and calculate the flying sand rate.

[0125] Sagging resistance: Measured according to JG / T24 method, record the maximum wet film thickness (mm) that does not sag.

[0126] Color dot integrity rate: Take a certain amount of paint and stir it in a mixer at 800 rpm for 10 minutes. Take samples before and after stirring, count the number of color dots under a microscope, and calculate the color dot integrity rate.

[0127] The test results are as follows:

[0128] Example 1: Initial viscosity 1050 mPa·s, viscosity 2850 mPa·s after 30 days of heat storage, viscosity change rate +171%, colored sand settling condition: no hard sediment, flying sand rate 5.2%, anti-sagging 1800 mm, colored spot integrity rate 98%.

[0129] Example 2: Initial viscosity 980 mPa·s, viscosity after 30 days of heat storage 2650 mPa·s, viscosity change rate +170%, colored sand settling condition: no hard sediment, flying sand rate 5.8%, anti-sagging 1750 mm, colored spot integrity rate 97%.

[0130] Example 3: Initial viscosity 1120 mPa·s, viscosity after 30 days of heat storage 3050 mPa·s, viscosity change rate +172%, colored sand settling condition: no hard sediment, flying sand rate 4.9%, anti-sagging 1850 mm, colored spot integrity rate 98%.

[0131] Comparative Example 1: Initial viscosity 3800 mPa·s, viscosity after 30 days of heat storage 8500 mPa·s (in a semi-gel state), viscosity change rate +124%, colored sand settling was slight precipitation, flying sand rate 12.8%, anti-sagging 1200 mm, colored dot integrity rate 85%.

[0132] Comparative Example 2: Initial viscosity 280 mPa·s, viscosity 450 mPa·s after 30 days of heat storage, viscosity change rate +61%, colored sand settling was severe sedimentation, flying sand rate 18.5%, anti-sagging 800 mm, colored spot integrity rate 70%.

[0133] Comparative Example 3: Initial viscosity 1020 mPa·s, viscosity 1980 mPa·s after 30 days of heat storage, viscosity change rate +94%, colored sand settling was slight sedimentation, fly sand rate 9.5%, anti-sagging 1400 mm, colored spot integrity rate 88%. During pH adjustment, local flocculation was observed in the system, and slight color bleeding was observed at the edges of the colored spots.

[0134] Comparative Example 4: Initial viscosity 1650 mPa·s, viscosity after 30 days of heat storage 4250 mPa·s, viscosity change rate +158%, colored sand settling was slight sedimentation, flying sand rate 10.2%, anti-sagging 1350 mm, colored spot integrity rate 82%.

[0135] The test results show that Examples 1 to 3 are significantly superior to the Comparative Examples in terms of overall performance. Although the viscosity change rate of Examples 1 to 3 is around 170% after heat storage, this is due to the formation of the hydrophobic associative network of component B, which is within the effective post-thickening range of the design, and the final viscosity is still within the workable range. Comparative Example 1 has an excessively high initial viscosity, approaching gel after heat storage; Comparative Example 2 has serious sedimentation and fly sand problems; Comparative Example 3 has an excessively fast pH recovery rate, which affects the uniform formation of the cellulose network; Comparative Example 4 uses a single cellulose system, which is inferior to the present invention in terms of viscosity balance during granulation, storage, and application.

[0136] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. The scope of patent protection of the present invention shall be determined by the claims. Similarly, any equivalent structural changes made based on the content of the present invention's specification shall also be included within the scope of protection of the present invention.

Claims

1. A multi-colored stone-like paint for coatings, characterized in that, The system comprises a composite cellulose system, wherein the composite cellulose is composed of low molecular weight hydroxyethyl cellulose of component A and high molecular weight hydrophobically modified hydroxyethyl cellulose of component B, wherein the molecular weight of component A is 20,000 to 40,000 and the viscosity of a 2% aqueous solution is 100 mPa·s to 500 mPa·s. The molecular weight of component B is 100,000 to 150,000, the viscosity of a 2% aqueous solution is 3,000 mPa·s to 8,000 mPa·s, and it is modified with C12 to C18 long-chain hydrophobic alkyl groups.

2. The multi-colored stone-like paint for coatings according to claim 1, characterized in that, The weight ratio of component A to component B is 1:1 to 1:2.

5.

3. The multi-colored stone-like paint for coatings according to claim 1, characterized in that, The preparation process of the colorful stone paint involves a gradient release process in which the pH is adjusted from 9.0 to 10.0 to 7.5 to 8.

5.

4. The multi-colored stone-like paint for coatings according to claim 3, characterized in that, The pH reduction process uses organic acids for slow adjustment, with the pH decrease rate controlled to no more than 0.2 per minute.

5. The multi-colored stone-like paint for coatings according to claim 1, characterized in that, The product comprises, by weight, 40 to 60 parts of base paint, 30 to 50 parts of granulation liquid, and 10 to 20 parts of continuous phase.

6. The multi-colored stone-like paint for coatings according to claim 5, characterized in that, The base paint comprises, by weight, the following: Water: 20 to 30 parts; Component A: 0.2 to 0.4 parts; Component B: 0.3 to 0.5 parts; Multifunctional pH adjuster: 0.1 to 0.2 parts; Dispersant: 0.3 to 0.6 parts; Wetting agent: 0.1 to 0.2 parts; Titanium dioxide: 2 to 5 parts; Calcined kaolin: 5 to 10 parts; Triple calcium: 10 to 15 parts; Colored sand: 40 to 50 parts; Pure acrylic emulsion: 15 to 20 parts; Film-forming aid: 0.8 to 1.5 parts; Fungicide: 0.1 to 0.2 parts.

7. The multi-colored stone-like paint for coatings according to claim 5, characterized in that, The granulation solution comprises, by weight: water: 94 to 97 parts, lithium magnesium silicate: 3 to 5 parts, and preservative: 0.1 to 0.2 parts.

8. A method for preparing a multicolored stone-like paint for coatings according to any one of claims 1 to 7, characterized in that, Includes the following steps: Step 1: Prepare a base paint containing component A and component B under pH conditions of 9.0 to 10.0; Step 2: Granulate the base paint obtained in Step 1 to form colored particles; Step 3: Slowly lower the pH of the system to 7.5 to 8.5 to trigger the formation of the hydrophobic association network of component B; Step 4: Add the continuous phase and stir until well mixed.

9. The preparation method according to claim 8, characterized in that, In the third step, a 10% citric acid aqueous solution is used to adjust the pH by adding it dropwise, with the drop rate controlled so that the pH decreases by no more than 0.2 every 10 minutes.

10. The preparation method according to claim 8, characterized in that, The specific steps for preparing the base paint in the first step are as follows: add water to the dispersion tank and start stirring; Slowly add component A and component B, stirring until no obvious lumps remain; Add a multi-functional pH adjuster to adjust the pH to 9.0 to 10.0, and continue stirring until the cellulose is completely dissolved; Add the dispersant, wetting agent, and bactericide in sequence, and stir until well mixed; Add titanium dioxide, calcined kaolin, and heavy calcium carbonate, and disperse at high speed until the fineness is less than or equal to 60μm; Reduce the rotation speed, add colored sand, pure acrylic emulsion, and film-forming aid, and stir evenly.