Coating matting agent and preparation process thereof

Abstract

The invention relates to the field of coatings, in particular to a coating delustering agent and a preparation process thereof. The preparation process of the delustering agent comprises the following steps: step 1, preparing aminated aluminum silicate powder; step 2, reacting allyl alcohol glycidyl ether with the aminated aluminum silicate powder to obtain activated aluminum silicate powder; and step 3, initiating polymerization reaction by using styrene, dimethyl vinylphosphonate and the activated aluminum silicate powder to obtain modified aluminum silicate powder, namely the coating matting agent. The delustering agent is prepared by taking aluminum silicate as a main base material and carrying out surface modification treatment on the aluminum silicate. Compared with conventional inorganic silicon matting agents, the matting agent prepared by the method is higher in surface activity, more suitable for water-based coatings, more excellent in dispersity and capable of enhancing the impact resistance and the heat and humidity resistance of the coatings to a certain extent on the basis of ensuring the matting rate.

Description

Technical Field

[0001] The invention relates to the field of coatings, and in particular to a coating matting agent and a preparation process thereof. Background Art

[0002] Paint matting agents are a type of material used to reduce the gloss of the coating surface. They affect the reflection and scattering of light on the coating surface by physical or chemical means to achieve a matting effect. Physical matting is to add a matting agent to the coating to make its surface uneven during the film-forming process, increase the scattering of light and reduce reflection, thereby producing a matting effect. Chemical matting is to introduce some structures or groups that can absorb light, such as polypropylene grafted substances, into the coating to obtain low gloss. Among them, there are three main types of matting agents used as physical matting materials: synthetic wax matting agents; metal soap matting agents; inorganic silicon matting agents. Among them, synthetic wax matting agents and metal soap matting agents are mainly used for oily coatings, and have the disadvantages of poor chemical stability, low aging resistance and high prices. Most of the current coating systems use inorganic silicone matting agents, which have good matting efficiency and film transparency. They do not require a large amount of addition to produce strong matting performance, which is of positive significance for reducing the use of other ingredients in the coating. However, inorganic silicone matting agents are prone to precipitation and have poor resistance to moisture and heat. After being used under wet and hot conditions for a period of time, the product surface becomes white or turbid, which greatly affects the performance of the coating. Summary of the invention

[0003] In view of the problems existing in the prior art, the purpose of the present invention is to provide a coating matting agent and a preparation process thereof.

[0004] The purpose of the present invention is achieved by the following technical solutions:

[0005] In a first aspect, the present invention provides a process for preparing a coating matting agent, comprising the following steps:

[0006] Step 1, amination treatment:

[0007] The aluminum silicate powder and the silane coupling agent KH-550 are mixed into an ethanol aqueous solution, kept warm and refluxed in a water bath, then naturally cooled to room temperature, centrifuged to collect the precipitate, washed and dried to obtain the amino aluminum silicate powder;

[0008] Step 2, surface activation:

[0009] Weigh allyl alcohol glycidyl ether and add it to anhydrous ethanol. After stirring evenly at room temperature, add amino aluminum silicate powder, place in a water bath and reflux and stir. After the reaction is completed, remove the solvent under reduced pressure to obtain activated aluminum silicate powder.

[0010] Step 3, surface modification:

[0011] Weigh styrene and dimethyl vinylphosphonate, add them to anhydrous ethanol, mix evenly, then add activated aluminum silicate powder and dispersant, stir until evenly dispersed, add initiator under nitrogen protection, heat and stir in a water bath to react, after the reaction is completed, centrifuge, wash and dry to obtain modified aluminum silicate powder, i.e., coating matting agent.

[0012] Preferably, in step 1, the particle size of the aluminum silicate powder is 5-10 μm, and the mass fraction of the ethanol aqueous solution is 10%-60%.

[0013] Preferably, in step 1, the mass ratio of aluminum silicate powder, silane coupling agent KH-550 and ethanol aqueous solution is 1:0.1-0.5:15-30.

[0014] Preferably, in step 1, the temperature of the water bath is 60-70° C., and the reflux time is 5-10 h.

[0015] Preferably, in step 2, the mass ratio of the amino aluminum silicate powder, allyl alcohol glycidyl ether and anhydrous ethanol is 1:0.22-0.44:20-40.

[0016] Preferably, in step 2, the temperature of reflux stirring is 60-80° C., and the reflux stirring time is 4-8 h.

[0017] Preferably, in step 3, the mass ratio of activated aluminum silicate powder, styrene, dimethyl vinylphosphonate and anhydrous ethanol is 1:0.52-1.04:0.13-0.26:20-40.

[0018] Preferably, in step 3, the dispersant is polyvinyl pyrrolidone, and the added amount is 5%-15% of the mass of styrene.

[0019] Preferably, in step 3, the initiator is azobisisobutyronitrile or azobisisoheptanenitrile, and the added amount is 0.5%-5% of the mass of styrene.

[0020] Preferably, in step 3, the reaction temperature is 65-85° C., and the reaction time is 15-20 h.

[0021] In a second aspect, the present invention provides a coating matting agent, which is prepared by the above-mentioned preparation method.

[0022] In a third aspect, the present invention provides an application of a coating matting agent in coatings, particularly in water-based coatings.

[0023] Preferably, the matting agent is added in an amount of 2wt%-20wt% in the coating.

[0024] The beneficial effects of the present invention are:

[0025] 1. The present invention prepares a matting agent for coatings, which is prepared by using aluminum silicate as the main base material and performing surface modification on the aluminum silicate. Compared with conventional inorganic silicon matting agents, the matting agent prepared by the present invention has stronger surface activity, is more suitable for water-based coatings, has better dispersibility, and can enhance the impact resistance and moisture and heat resistance of the coating to a certain extent while ensuring the matting rate.

[0026] 2. Compared with silicon dioxide, aluminum silicate has better stability and compression resistance. Therefore, the present invention replaces conventional silicon dioxide with aluminum silicate, and then prepares a matting agent after surface modification. The modification process of the aluminum silicate surface includes: first treating the aluminum silicate powder with a coupling agent to obtain amino aluminum silicate powder; then reacting with the cross-linking agent allyl alcohol glycidyl ether to form an amino-epoxy bonding reaction to obtain aluminum silicate powder containing double bonds; then mixing with styrene and dimethyl vinylphosphonate, initiating polymerization, and finally obtaining an organic-inorganic composite coated modified material.

[0027] 3. In the surface modification process of aluminum silicate of the present invention, in addition to styrene, dimethyl vinylphosphonate is also added as a modifier. It is found through testing that, compared with simple styrene polymerization modification, the addition of the modifier enables the prepared matting agent to have a certain improvement in the impact resistance and moisture and heat resistance of the coating. DETAILED DESCRIPTION

[0028] The technical solution of the present invention is described below through specific examples. It should be understood that the one or more method steps mentioned in the present invention do not exclude the existence of other method steps before and after the combination step or the insertion of other method steps between these explicitly mentioned steps; it should also be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or to limit the scope of the present invention. The change or adjustment of the relative relationship thereof shall also be regarded as the scope of the present invention without substantially changing the technical content.

[0029] In order to better understand the above technical scheme, the exemplary embodiments of the present invention are described in more detail below. Although exemplary embodiments of the present invention are shown, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0030] The present invention will be further described below in conjunction with the following examples.

[0031] Example 1

[0032] A preparation process of a coating matting agent comprises the following steps:

[0033] Step 1, amination treatment:

[0034] Aluminum silicate powder with a particle size of 5-10 μm and silane coupling agent KH-550 are mixed into an ethanol aqueous solution with a mass fraction of 30%, and the mass ratio of aluminum silicate powder, silane coupling agent KH-550 and ethanol aqueous solution is 1:0.3:25. The mixture is heated to 65° C. in a water bath, kept under reflux for 8 hours, and then naturally cooled to room temperature. The precipitate is collected by centrifugation, rinsed with distilled water for 3 times, and dried to obtain amino aluminum silicate powder;

[0035] Step 2, surface activation:

[0036] Weigh allyl alcohol glycidyl ether and add it to anhydrous ethanol. After stirring evenly at room temperature, add amino aluminum silicate powder. The mass ratio of amino aluminum silicate powder, allyl alcohol glycidyl ether and anhydrous ethanol is 1:0.33:40. Place in a water bath and reflux and stir at 70°C for 6 hours. After the reaction is completed, remove the solvent under reduced pressure to obtain activated aluminum silicate powder.

[0037] Step 3, surface modification:

[0038] Styrene and dimethyl vinylphosphonate are weighed and added to anhydrous ethanol, mixed evenly, and then activated aluminum silicate powder is added, the mass ratio of activated aluminum silicate powder, styrene, dimethyl vinylphosphonate and anhydrous ethanol is 1:0.78:0.19:30, and polyvinyl pyrrolidone is added as a dispersant at the same time, and the added amount is 10% of the mass of styrene. After stirring until the dispersion is uniform, under the protection of nitrogen, an initiator azobisisobutyronitrile is added at an amount of 2.5% of the mass of styrene, the temperature is raised to 75°C in a water bath, and the reaction is stirred for 18 hours. After the reaction is completed, the mixture is cooled to room temperature, and a solid product is separated by centrifugation, which is rinsed three times with ethanol and then dried in a vacuum oven to obtain a modified aluminum silicate powder, i.e., a coating matting agent.

[0039] Example 2

[0040] A preparation process of a coating matting agent comprises the following steps:

[0041] Step 1, amination treatment:

[0042] Aluminum silicate powder with a particle size of 5-10 μm and silane coupling agent KH-550 are mixed into an ethanol aqueous solution with a mass fraction of 20%, and the mass ratio of aluminum silicate powder, silane coupling agent KH-550 and ethanol aqueous solution is 1:0.2:18. The mixture is heated to 60° C. in a water bath, kept under reflux for 10 hours, and then naturally cooled to room temperature. The precipitate is collected by centrifugation, rinsed with distilled water for 3 times, and dried to obtain amino aluminum silicate powder;

[0043] Step 2, surface activation:

[0044] Weigh allyl alcohol glycidyl ether and add it to anhydrous ethanol. After stirring evenly at room temperature, add amino aluminum silicate powder. The mass ratio of amino aluminum silicate powder, allyl alcohol glycidyl ether and anhydrous ethanol is 1:0.28:40. Place in a water bath and reflux and stir for 7 hours at 65° C. After the reaction is completed, remove the solvent under reduced pressure to obtain activated aluminum silicate powder;

[0045] Step 3, surface modification:

[0046] Styrene and dimethyl vinylphosphonate are weighed and added to anhydrous ethanol, mixed evenly, and then activated aluminum silicate powder is added, the mass ratio of activated aluminum silicate powder, styrene, dimethyl vinylphosphonate and anhydrous ethanol is 1:0.67:0.18:30, and polyvinyl pyrrolidone is added as a dispersant at the same time, and the added amount is 11% of the mass of styrene. After stirring until the dispersion is uniform, under the protection of nitrogen, an initiator azobisisobutyronitrile or azobisisoheptanenitrile is added at an amount of 1.5% of the mass of styrene, and the temperature is raised to 70° C. in a water bath, and the reaction is stirred for 16 hours. After the reaction is completed, the solid product is separated by centrifugation, rinsed with ethanol three times, and then dried in a vacuum box to obtain modified aluminum silicate powder, i.e., a coating matting agent.

[0047] Example 3

[0048] A preparation process of a coating matting agent comprises the following steps:

[0049] Step 1, amination treatment:

[0050] Aluminum silicate powder with a particle size of 5-10 μm and silane coupling agent KH-550 are mixed into an ethanol aqueous solution with a mass fraction of 50%, and the mass ratio of aluminum silicate powder, silane coupling agent KH-550 and ethanol aqueous solution is 1:0.4:20. The mixture is heated to 70° C. in a water bath, kept under reflux for 5 hours, and then naturally cooled to room temperature. The precipitate is collected by centrifugation, rinsed with distilled water for 2-4 times, and dried to obtain amino aluminum silicate powder;

[0051] Step 2, surface activation:

[0052] Weigh allyl alcohol glycidyl ether and add it to anhydrous ethanol. After stirring evenly at room temperature, add amino aluminum silicate powder. The mass ratio of amino aluminum silicate powder, allyl alcohol glycidyl ether and anhydrous ethanol is 1:0.4:40. Place in a water bath and reflux and stir at 70° C. for 8 hours. After the reaction is completed, remove the solvent under reduced pressure to obtain activated aluminum silicate powder.

[0053] Step 3, surface modification:

[0054] Styrene and dimethyl vinylphosphonate are weighed and added to anhydrous ethanol, mixed evenly, and then activated aluminum silicate powder is added, the mass ratio of activated aluminum silicate powder, styrene, dimethyl vinylphosphonate and anhydrous ethanol is 1:0.86:0.21:40, and polyvinyl pyrrolidone is added as a dispersant at the same time, and the added amount is 10% of the mass of styrene. After stirring until the dispersion is uniform, under the protection of nitrogen, an initiator azobisisobutyronitrile or azobisisoheptanenitrile is added at an amount of 4% of the mass of styrene, and the temperature is raised to 75° C. in a water bath, and the reaction is stirred for 15 hours. After the reaction is completed, the solid product is separated by centrifugation, rinsed with ethanol three times, and then dried in a vacuum box to obtain modified aluminum silicate powder, i.e., a coating matting agent.

[0055] Example 4

[0056] A preparation process of a coating matting agent comprises the following steps:

[0057] Step 1, amination treatment:

[0058] Aluminum silicate powder with a particle size of 5-10 μm and silane coupling agent KH-550 are mixed into an ethanol aqueous solution with a mass fraction of 10%, and the mass ratio of aluminum silicate powder, silane coupling agent KH-550 and ethanol aqueous solution is 1:0.1:15. The mixture is heated to 60° C. in a water bath, kept under reflux for 5 hours, and then naturally cooled to room temperature. The precipitate is collected by centrifugation, rinsed twice with distilled water, and dried to obtain amino aluminum silicate powder;

[0059] Step 2, surface activation:

[0060] Weigh allyl alcohol glycidyl ether and add it to anhydrous ethanol. After stirring evenly at room temperature, add amino aluminum silicate powder. The mass ratio of amino aluminum silicate powder, allyl alcohol glycidyl ether and anhydrous ethanol is 1:0.22:20. Place in a water bath and reflux and stir for 4 hours at 60° C. After the reaction is completed, remove the solvent under reduced pressure to obtain activated aluminum silicate powder;

[0061] Step 3, surface modification:

[0062] Styrene and dimethyl vinylphosphonate are weighed and added to anhydrous ethanol, mixed evenly, and then activated aluminum silicate powder is added, the mass ratio of activated aluminum silicate powder, styrene, dimethyl vinylphosphonate and anhydrous ethanol is 1:0.52:0.13:20, and polyvinyl pyrrolidone is added as a dispersant at the same time, and the added amount is 5% of the mass of styrene. After stirring until the dispersion is uniform, under the protection of nitrogen, an initiator azobisisobutyronitrile or azobisisoheptanenitrile is added at a amount of 0.5% of the mass of styrene, and the temperature is raised to 65° C. in a water bath, and the reaction is stirred for 15 hours. After the reaction is completed, the solid product is separated by centrifugation, rinsed with ethanol three times, and then dried in a vacuum box to obtain modified aluminum silicate powder, i.e., a coating matting agent.

[0063] Example 5

[0064] A preparation process of a coating matting agent comprises the following steps:

[0065] Step 1, amination treatment:

[0066] Aluminum silicate powder with a particle size of 5-10 μm and silane coupling agent KH-550 are mixed into an ethanol aqueous solution with a mass fraction of 60%, and the mass ratio of aluminum silicate powder, silane coupling agent KH-550 and ethanol aqueous solution is 1:0.5:30. The mixture is heated to 70° C. in a water bath, kept under reflux for 10 hours, and then naturally cooled to room temperature. The precipitate is collected by centrifugation, rinsed with distilled water for 4 times, and dried to obtain amino aluminum silicate powder;

[0067] Step 2, surface activation:

[0068] Weigh allyl alcohol glycidyl ether and add it to anhydrous ethanol. After stirring evenly at room temperature, add amino aluminum silicate powder. The mass ratio of amino aluminum silicate powder, allyl alcohol glycidyl ether and anhydrous ethanol is 1:0.44:40. Place in a water bath and reflux and stir at 80° C. for 8 hours. After the reaction is completed, remove the solvent under reduced pressure to obtain activated aluminum silicate powder.

[0069] Step 3, surface modification:

[0070] Styrene and dimethyl vinylphosphonate are weighed and added to anhydrous ethanol, mixed evenly, and then activated aluminum silicate powder is added, the mass ratio of activated aluminum silicate powder, styrene, dimethyl vinylphosphonate and anhydrous ethanol is 1:1.04:0.26:40, and polyvinyl pyrrolidone is added as a dispersant at the same time, and the added amount is 15% of the mass of styrene. After stirring until the dispersion is uniform, under the protection of nitrogen, an initiator azobisisobutyronitrile or azobisisoheptanenitrile is added at an amount of 5% of the mass of styrene, and the temperature is raised to 85°C in a water bath, and the reaction is stirred for 20 hours. After the reaction is completed, the solid product is separated by centrifugation, rinsed with ethanol three times, and then dried in a vacuum box to obtain modified aluminum silicate powder, i.e., a coating matting agent.

[0071] Comparative Example 1

[0072] A coating matting agent, which differs from Example 1 in that only amino aluminum silicate powder is used as the matting agent, and the preparation process of the amino aluminum silicate powder is the same as that of Example 1.

[0073] Comparative Example 2

[0074] A coating matting agent, which differs from Example 1 in that only activated aluminum silicate powder is used as the matting agent, and the preparation process of the activated aluminum silicate powder is the same as that of Example 1.

[0075] Comparative Example 3

[0076] A coating matting agent, which differs from Example 1 in that during the surface modification process in step 3, no modifier dimethyl vinylphosphonate is added, and an equal amount of polystyrene is used instead. Specifically, the preparation method comprises:

[0077] Step 1 and step 2 are the same as those in Example 1.

[0078] Step 3, surface modification:

[0079] Weigh styrene and add it to anhydrous ethanol, mix evenly, then add activated aluminum silicate powder, the mass ratio of activated aluminum silicate powder, styrene and anhydrous ethanol is 1:0.97:30, and polyvinyl pyrrolidone is added as a dispersant at the same time, the addition amount is 10% of the mass of styrene, after stirring until uniform dispersion, under the protection of nitrogen, add initiator azobisisobutyronitrile, the addition amount is 2.5% of the mass of styrene, heat to 75°C in a water bath, stir and react for 18 hours, after the reaction is completed, centrifuge to separate the solid product, rinse with ethanol three times, and then dry in a vacuum box to obtain modified aluminum silicate powder, i.e., coating matting agent.

[0080] Application and testing

[0081] The matting agents prepared in Example 1 and Comparative Examples 1-3 were applied to water-based acrylic resin coatings, and then the performance of the coatings was tested.

[0082] The components of the water-based acrylic resin coating are calculated by weight and include:

[0083] 100 parts of water-based acrylic resin FX-W9282 (Nantong Fangxin), 5 parts of matting agent, 1 part of dispersant TEGO-752W, 0.6 parts of defoamer BYK-028, 1.5 parts of wetting agent BYK-348 and 30 parts of deionized water.

[0084] The matting agents in the above coatings were respectively the matting agents of Example 1 and Comparative Examples 1-3, so as to prepare 4 coatings, which were then coated on stainless steel plates with a coating thickness of (100±0.1) μm. After drying at room temperature for 7 days, the performance was tested. The glossiness of the paint film was tested according to the reference standard ISO 2813:2014, the impact resistance was tested according to the reference standard GB / T1732-1993, and the moisture and heat resistance was tested at 65°C and 90RH% for 120h, and then the surface of the paint film was observed. The test results are shown in Table 1:

[0085] Table 1 Performance of different matting agents in coatings

[0086]

[0087] It can be seen from the test results in Table 1 that the matting agent prepared in Example 1 of the present invention, after being applied to the water-based acrylic paint, can maintain a low gloss while also having good impact resistance and moisture and heat resistance, and is more suitable for use in relatively harsh environments.

[0088] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms should not be understood as necessarily being directed to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0089] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A process for preparing a coating matting agent, characterized in that: The following steps are involved: Step 1, mixing aluminum silicate powder and silane coupling agent KH-550 into an ethanol aqueous solution, refluxing in a water bath, then naturally cooling to room temperature, collecting the precipitate by centrifugation, washing and drying, to obtain amino aluminum silicate powder; Step 2, weighing allyl alcohol glycidyl ether and adding it to anhydrous ethanol, stirring evenly at room temperature, then adding amino aluminum silicate powder, placing in a water bath and reflux stirring, after the reaction is completed, removing the solvent under reduced pressure to obtain activated aluminum silicate powder; Step 3, weigh styrene and dimethyl vinylphosphonate, add them to anhydrous ethanol, mix them evenly, then add activated aluminum silicate powder, add dispersant at the same time, stir until dispersed evenly, add initiator under the protection of nitrogen, heat and stir in a water bath to react, after the reaction is completed, centrifuge, wash and dry to obtain modified aluminum silicate powder, i.e., coating matting agent.

2. The preparation process of a coating matting agent according to claim 1, characterized in that: In the step 1, the particle size of the aluminum silicate powder is 5-10 μm, the mass fraction of the ethanol aqueous solution is 10%-60%; the mass ratio of the aluminum silicate powder, the silane coupling agent KH-550 and the ethanol aqueous solution is 1:0.1-0.5:15-30.

3. The preparation process of a coating matting agent according to claim 1, characterized in that: In the step 1, the temperature of the water bath is 60-70° C., and the reflux time is 5-10 h.

4. The process for preparing a coating matting agent according to claim 1, characterized in that: In the step 2, the mass ratio of the amino aluminum silicate powder, allyl alcohol glycidyl ether and anhydrous ethanol is 1:0.22-0.44:20-40.

5. The preparation process of a coating matting agent according to claim 1, characterized in that: In the step 2, the temperature of reflux stirring is 60-80° C., and the reflux stirring time is 4-8 hours.

6. The process for preparing a coating matting agent according to claim 1, characterized in that: In the step 3, the mass ratio of activated aluminum silicate powder, styrene, dimethyl vinylphosphonate and anhydrous ethanol is 1:0.52-1.04:0.13-0.26:20-40.

7. The process for preparing a coating matting agent according to claim 1, characterized in that: In the step 3, the dispersant is polyvinyl pyrrolidone, and the added amount is 5%-15% of the mass of styrene; the initiator is azobisisobutyronitrile or azobisisoheptanenitrile, and the added amount is 0.5%-5% of the mass of styrene.

8. The process for preparing a coating matting agent according to claim 1, characterized in that: In step 3, the reaction temperature is 65-85° C. and the reaction time is 15-20 h.

9. A coating matting agent, characterized in that: The matting agent is prepared by the preparation method described in claim 1.

10. Use of the coating matting agent according to claim 9, characterized in that: The coating matting agent is applied to water-based coatings.

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