Sanding slurry capable of being stored for long time and preparation method thereof

Abstract

The invention relates to sanding slurry capable of being stored for a long time, which is prepared from the following components in percentage by mass: 20 to 70 percent of pigment and filler, 0.7 to 2 percent of macromolecular dispersing agent, 0.4 to 1 percent of anionic dispersing agent, 0.1 to 5 percent of polyamide wax, 0.21 to 5 percent of auxiliary agent, 0.1 to 2 percent of talcum powder, 0 to 10 percent of solvent and 20 to 60 percent of pure water, and the total mass percentage of the components is 100 percent. According to the sanding slurry capable of being stored for a long time, the polymer dispersing agent and the anionic dispersing agent are compounded for use, so that the stability of the inorganic filler in the slurry and the compatibility of the inorganic filler and paint color matching slurry are improved, and the grinding efficiency is improved. The slurry does not contain grinding resin, grinding is more sufficient, the grid structure of a slurry system is increased by adding polyamide wax, and toner precipitation is reduced. The obtained sanding slurry is high in stability, can be stored for a long time, is lower in grinding fineness, and can bring better paint film performance after being used. The invention also comprises a preparation method of the sanding slurry capable of being stored for a long time.

Description

Technical Field

[0001] This invention relates to the field of coatings, and more specifically to a sand-milling slurry that can be stored for a long time, and a method for preparing the sand-milling slurry. Background Technology

[0002] In the coatings manufacturing industry, sand-milled slurry is an important intermediate product in the production of water-based intermediate coats and primers. Currently, coating manufacturers typically prepare sand-milled slurry by mixing pigments, fillers, additives, resins, and other components in a specific ratio, and then grinding the mixture evenly using a sand mill. This production method has two drawbacks: firstly, the sand-milled slurry cannot be stored for long periods and needs to be quickly formulated into intermediate coats or primers; secondly, different intermediate coats or primers require different sand-milled slurries, making the production process difficult to control and easily leading to waste.

[0003] In view of this, there is an urgent need in the field to develop a sand grinding slurry that can be stored for a long time in order to solve the problems existing in the prior art. Summary of the Invention

[0004] Based on the above facts, the purpose of this invention is to provide a long-term slurry that utilizes a combination of polymeric and anionic dispersants to improve the stability of inorganic fillers in the slurry, increase the compatibility between inorganic fillers and paint tinting pastes, and improve grinding efficiency. It contains no grinding resin, allowing for more thorough grinding, and the addition of polyamide wax increases the network structure of the slurry system, reducing pigment sedimentation. The resulting slurry exhibits high stability, can be stored for extended periods, and has a finer grinding particle size, resulting in better paint film performance after use.

[0005] A first aspect of the present invention provides a long-term slurry for grinding, comprising, by weight percentage:

[0006]

[0007]

[0008] The total mass percentage of all the above components is 100%.

[0009] Pigments and fillers

[0010] In this invention, the pigments and fillers are selected from barium sulfate paste or titanium dioxide paste. The sand-milling slurry containing barium sulfate paste or titanium dioxide paste can be combined in different proportions to handle the production of different types of intermediate coatings or primers, thereby reducing the number of types of sand-milling slurries and simplifying the production process.

[0011] Polymer dispersants and anionic dispersants

[0012] In this invention, the polymeric dispersant can improve the stability of inorganic fillers in the grinding slurry and increase the compatibility between inorganic fillers and paint color pastes; the anionic dispersant can improve the grinding efficiency and stability of inorganic fillers.

[0013] Preferably, the ratio of the polymeric dispersant to the anionic dispersant is selected from any ratio between 1:1 and 3:1; more preferably, the ratio of the polymeric dispersant to the anionic dispersant is 2:1.

[0014] Specifically, the polymeric dispersant is selected from the dispersant model Dispex Ultra Px 4575, and the anionic dispersant is selected from the dispersant model Disperbx DIC01.

[0015] Polyamide wax

[0016] In this invention, polyamide wax can form hydrogen bonds with amide bonds in the dispersant, thereby increasing the grid structure of the slurry system and reducing pigment precipitation, thus improving the storage stability of the sand milling slurry.

[0017] Additives

[0018] In this invention, the additives are selected from one or more of rheology modifiers, defoamers, and pH adjusters, and the long-term slurry comprises, by mass percentage:

[0019] Rheology modifier 0.1-2%

[0020] Defoamer 0.01-2%

[0021] pH adjuster 0.1-2%

[0022] The total mass percentage of all the above components is 0.21-5%.

[0023] Specifically, the rheology modifier is preferably one or a combination of the rheology modifier LAPONITE RD provided by BYK, fumed silica, etc.; the defoamer is preferably the defoamer SURFYNOL104A provided by Evonik.

[0024] solvent

[0025] In some embodiments of the present invention, the solvent is ethylene glycol butyl ether.

[0026] A second aspect of the present invention provides a method for preparing the long-term storage sand slurry described in the first aspect of the present invention, comprising the following steps:

[0027] S1: Add pure water, solvent, part of the polymeric dispersant, anionic dispersant, polyamide wax, additives, and talc to a mixer with a speed of 300-700 rpm in sequence, and continue stirring for 5-10 minutes;

[0028] S2: Keep the rotation speed constant, continue to add pigments and fillers, increase the rotation speed to 800-1200 rpm, and continue stirring for 10-15 minutes to obtain a uniformly mixed slurry to be ground;

[0029] S3: Transfer the slurry to be ground into the grinder and grind it at a speed of 3200-3800 rpm, a temperature of less than 40℃, and a grinding pressure of less than 0.2MPa to obtain a grinding slurry with a fineness of less than 20μm.

[0030] S4: Add the remaining polymeric dispersant to the grinding slurry, and grind again under the conditions of 3200-3800 rpm, temperature less than 40℃, and grinding pressure less than 0.2 MPa to obtain the sand grinding slurry that can be stored for a long time.

[0031] The preparation method, by adding polymeric dispersants in batches, can effectively increase the content of free dispersants in the grinding slurry, reduce the precipitation of dispersants on the surface of pigment particles, and improve the stability of the grinding slurry. Simultaneously, adding polymeric dispersants in batches can also improve compatibility, reduce the risk of skin-tone color variations, improve the wettability of the grinding slurry, and reduce problems such as drying and agglomeration of the grinding slurry.

[0032] Beneficial effects of the present invention

[0033] This invention addresses the shortcomings of existing technologies by providing a long-term slurry that utilizes a combination of polymeric and anionic dispersants. This combination improves the stability of inorganic fillers in the slurry, increases the compatibility between inorganic fillers and paint tinting pastes, and enhances grinding efficiency. It contains no grinding resin, allowing for more thorough grinding, and the addition of polyamide wax increases the network structure of the slurry system, reducing pigment sedimentation. The resulting slurry exhibits high stability, can be stored for extended periods, and has a finer grinding particle size, resulting in better paint film performance after use. Detailed Implementation

[0034] To more clearly illustrate the present invention, specific embodiments are described below. Those skilled in the art should understand that the following description is illustrative rather than restrictive and should not be construed as limiting the scope of protection of the present invention.

[0035] Example 1: Barium sulfate slurry, a long-term storage material for sand milling.

[0036] Prepare a long-term storage sand milling slurry - barium sulfate slurry according to the formula shown in Table 1 below. The preparation steps are as follows.

[0037] S1: Add pure water, a portion of polymeric dispersant, anionic dispersant, polyamide wax, additives, and talc to a mixer with a speed of 300-700 rpm in sequence, and continue stirring for 5-10 minutes;

[0038] S2: Keep the rotation speed constant, continue to add pigments and fillers, increase the rotation speed to 800-1200 rpm, and continue stirring for 10-15 minutes to obtain a uniformly mixed slurry to be ground;

[0039] S3: Transfer the slurry to be ground into the grinder and grind it at a speed of 3200-3800 rpm, a temperature of less than 40℃, and a grinding pressure of less than 0.2MPa to obtain a grinding slurry with a fineness of less than 20μm.

[0040] S4: Add the remaining polymeric dispersant to the grinding slurry, and grind again under the conditions of 3200-3800 rpm, temperature less than 40℃, and grinding pressure less than 0.2 MPa to obtain the long-term slurry-barium sulfate slurry.

[0041] Comparative Examples 1-6: Barium sulfate slurry 1-6 as comparative examples

[0042] Barium sulfate slurry 1-6, as comparative examples, were prepared according to the formulations shown in Table 1 below. Except for the absence of certain components in some preparation steps, the other preparation steps were the same as in Example 1.

[0043] Table 1. Barium sulfate slurry formulations for Example 1 and Comparative Examples 1-6

[0044]

[0045]

[0046] As can be seen from Table 1, Comparative Example 1 does not contain anionic dispersant, Comparative Example 2 does not contain polymeric dispersant, Comparative Example 3 uses too little polymeric and anionic dispersant, Comparative Example 4 uses too much polymeric and anionic dispersant, Comparative Example 5 uses polymeric dispersant in a single addition, and Comparative Example 6 does not contain polyamide wax. Therefore, Comparative Examples 1-6 are not within the scope of protection of this invention.

[0047] Stability tests were conducted at the initial preparation stage, after 30 days of storage, after 60 days of storage, and after 90 days of storage. The results are shown in Table 2-5.

[0048] Table 2 Initial tests after the preparation of barium sulfate slurry in Example 1 and Comparative Examples 1-6

[0049]

[0050] As can be seen from Table 2, when the barium sulfate pastes of Examples 1 and Comparative Examples 1-6 were first prepared, the fineness and particle size of the pastes were basically the same, with little difference.

[0051] Table 3. Test results of barium sulfate slurry after 30 days of storage in Examples 1 and Comparative Examples 1-6.

[0052]

[0053] After 30 days of storage, the fineness of comparative examples 1, 2, and 6 increased significantly beyond the acceptable range, indicating poor storage stability, and the experiment was stopped.

[0054] Table 4. Test results of barium sulfate slurry after 60 days of storage in Examples 1 and Comparative Examples 3-5.

[0055]

[0056] After 60 days of storage, the fineness of Comparative Example 3 increased significantly beyond the acceptable range, and the experiment was stopped.

[0057] Table 5. Test results of barium sulfate slurry after 90 days of storage in Examples 1 and Comparative Examples 4-5.

[0058]

[0059] After 90 days of storage, the fineness of comparative samples 4 and 5 increased significantly beyond the acceptable range, and the experiment was stopped.

[0060] It can be seen that the sand-milling slurry obtained by the present invention has high stability and can be stored for a long time. After 90 days of storage, the fineness and particle size did not change significantly.

[0061] Example 2: Long-term storage of grinding slurry - titanium dioxide slurry

[0062] The long-term storage sand milling slurry - titanium dioxide slurry is prepared according to the formula shown in Table 6 below. The preparation steps are as follows.

[0063] S1: Add pure water, solvent, part of the polymeric dispersant, anionic dispersant, polyamide wax, additives, and talc to a mixer with a speed of 300-700 rpm in sequence, and continue stirring for 5-10 minutes;

[0064] S2: Keep the rotation speed constant, continue to add pigments and fillers, increase the rotation speed to 800-1200 rpm, and continue stirring for 10-15 minutes to obtain a uniformly mixed slurry to be ground;

[0065] S3: Transfer the slurry to be ground into the grinder and grind it at a speed of 3200-3800 rpm, a temperature of less than 40℃, and a grinding pressure of less than 0.2MPa to obtain a grinding slurry with a fineness of less than 20μm.

[0066] S4: Add the remaining polymeric dispersant to the grinding slurry, and grind again under the conditions of 3200-3800 rpm, temperature less than 40℃, and grinding pressure less than 0.2MPa to obtain the long-term slurry-titanium dioxide paste.

[0067] Comparative Examples 7-12: Titanium dioxide paste 7-12 as a comparative example

[0068] Titanium dioxide paste 7-12, as a comparative example, was prepared according to the formulation shown in Table 6 below. Except for the lack of corresponding components in some preparation steps, the other preparation steps were the same as in Example 2.

[0069] Table 6 Titanium Dioxide Formulations of Example 2 and Comparative Examples 7-12

[0070]

[0071] As can be seen from Table 6, Comparative Example 7 does not contain anionic dispersant, Comparative Example 8 does not contain polymeric dispersant, Comparative Example 9 uses too little polymeric and anionic dispersant, Comparative Example 10 uses too much polymeric and anionic dispersant, Comparative Example 11 uses polymeric dispersant in a single addition, and Comparative Example 12 does not contain polyamide wax. Therefore, Comparative Examples 7-12 are not within the scope of protection of this invention.

[0072] Stability tests were conducted at the initial preparation stage, after 30 days of storage, after 60 days of storage, and after 90 days of storage. The results are shown in Table 7-10.

[0073] Table 7 Initial tests after the preparation of titanium dioxide paste in Example 2 and Comparative Examples 7-12

[0074]

[0075]

[0076] As can be seen from Table 2, when the titanium dioxide pastes of Examples 2 and Comparative Examples 7-12 were first prepared, the fineness and particle size of the pastes were basically the same, with little difference.

[0077] Table 8. Test results of titanium dioxide paste in Example 2 and Comparative Examples 7-12 after 30 days of storage.

[0078]

[0079] After 30 days of storage, the fineness of comparative samples 7, 8, and 12 increased significantly beyond the acceptable range, indicating poor storage stability, and the experiment was stopped.

[0080] Table 9. Test results of titanium dioxide paste after 60 days of storage in Example 2 and Comparative Examples 9-11.

[0081]

[0082] After 60 days of storage, the fineness of Comparative Example 9 increased significantly beyond the acceptable range, and the experiment was stopped.

[0083] Table 10. Test results of titanium dioxide paste after 90 days of storage in Example 2 and Comparative Examples 10-11.

[0084]

[0085] After 90 days of storage, the fineness of comparative examples 10 and 11 increased significantly beyond the acceptable range, and the experiment was stopped.

[0086] It can be seen that the sand-milling slurry obtained by the present invention has high stability and can be stored for a long time. After 90 days of storage, the fineness and particle size did not change significantly.

[0087] Comparative Examples 13-14: Existing Process Grinding Slurry 1-2

[0088] The commonly used sand milling slurry 1-2 in the existing process is selected as comparative example 13-14 for further explanation. The slurry formulation is shown in Table 11.

[0089] Table 11 Formulas for Comparative Examples 13-14

[0090]

[0091] Stability tests were conducted at the initial preparation stage, 10 days of storage, 20 days of storage, 30 days of storage, 60 days of storage, and 90 days of storage, and the results are shown in Table 12.

[0092] Table 12 Comparison of storage stability of Examples 1-2 and Comparative Examples 13-14

[0093]

[0094]

[0095] As shown in Table 12, the sand milling slurry prepared by this invention can be stored for a long time and has good stability. In contrast, the sand milling slurry prepared by existing processes becomes less stable and unusable after being stored for more than 7 days.

[0096] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A long-term slurry for sanding, comprising, by weight percentage: The total mass percentage of all the above components is 100%.

2. The long-term slurry for grinding as described in claim 1, characterized in that, The pigments and fillers are selected from either barium sulfate paste or titanium dioxide paste.

3. The long-term slurry for grinding as described in claim 1, characterized in that, The ratio of the polymeric dispersant to the anionic dispersant is selected from any ratio between 1:1 and 3:1; preferably, the ratio of the polymeric dispersant to the anionic dispersant is 2:

1.

4. The long-term storable grinding slurry according to claim 1, characterized in that, The additives are selected from one or more of rheology modifiers, defoamers, and pH adjusters, and by mass percentage, the long-term slurry comprises: Rheology modifier 0.1-2% Defoamer 0.01-2% pH adjuster 0.1-2% The total mass percentage of all the above components is 0.21-5%.

5. The long-term slurry for grinding as described in claim 1, characterized in that, The solvent is ethylene glycol butyl ether.

6. A method for preparing a long-term slurry as described in any one of claims 1-5, comprising the following steps: S1: Add pure water, solvent, part of the polymeric dispersant, anionic dispersant, polyamide wax, additives, and talc to a mixer with a speed of 300-700 rpm in sequence, and continue stirring for 5-10 minutes; S2: Keep the rotation speed constant, continue to add pigments and fillers, increase the rotation speed to 800-1200 rpm, and continue stirring for 10-15 minutes to obtain a uniformly mixed slurry to be ground; S3: Transfer the slurry to be ground into the grinder and grind it at a speed of 3200-3800 rpm, a temperature of less than 40℃, and a grinding pressure of less than 0.2MPa to obtain a grinding slurry with a fineness of less than 20μm. S4: Add the remaining polymeric dispersant to the grinding slurry, and grind again under the conditions of 3200-3800 rpm, temperature less than 40℃, and grinding pressure less than 0.2 MPa to obtain the sand grinding slurry that can be stored for a long time.

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