Multipurpose strip-shaped aluminum pigment and preparation method thereof

Abstract

The invention relates to the technical field of aluminum pigments, in particular to a multipurpose strip-shaped aluminum pigment and a preparation method thereof. The multipurpose strip-shaped aluminum pigment is prepared by the preparation method. The preparation method comprises the following steps: S1, adding a passivator into a first dispersion of the aluminum pigment; carrying out filter pressing on the passivated aluminum pigment to form a first filter cake, and drying to obtain a dried aluminum pigment; s2, forming a second aluminum pigment dispersion from the dried aluminum pigment, heating, adjusting the pH value, and adding an organic silicon coating aid; carrying out filter pressing on the coated aluminum pigment to form a second filter cake; s3, heating and stirring the second filter cake, resoluble resin, macromolecular wax and an antioxidant to obtain a mixed material; and S4, after cooling the mixed material to normal temperature, extruding the mixed material into strips, and drying the strips to obtain the multipurpose strip-shaped aluminum pigment. The multi-purpose strip-shaped aluminum pigment prepared by the method can meet the environmental protection requirements of no solvation and solidification, and can also realize multi-purpose use.

Description

Technical Field

[0001] The invention relates to the technical field of aluminum pigments, and in particular to a multi-purpose strip aluminum pigment and a preparation method thereof. Background Art

[0002] Aluminum pigments, also known as aluminum powder pigments, have unique metallic luster, excellent weather resistance and high hiding power. Mixing them with transparent color pigments can make the paint film have obvious "angle-dependent color effect", and the decorative effect is very gorgeous and beautiful. Therefore, aluminum pigments are widely used in paints, inks, plastic spray-free coatings and powder coatings.

[0003] However, in different products, in order to meet the application requirements of the corresponding products, the aluminum pigments need to be subjected to corresponding surface treatment. This shows that the existing aluminum pigment products cannot be used for multiple purposes. For example, the aluminum pigments used in ink products cannot be used in plastic spray-free products and powder coating products. Specifically, the aluminum pigments in ink products are mainly slurry aluminum pigments, which contain solvents and cannot be used in powder coating products; the use of slurry aluminum pigments in plastic spray-free products also causes solvent volatilization, which affects the product molding performance; aluminum pigments used in powder coating products are prone to generate dust, and production and feeding are difficult, so they are not suitable for use in ink products, paint products and plastic spray-free products.

[0004] In addition, in order to meet environmental protection requirements, solvent-free and solid aluminum pigment products are increasingly favored by users. However, although the existing strip aluminum pigments can meet the environmental protection requirements of solvent-free and solid, they cannot be used for multiple purposes.

[0005] In summary, it is necessary to develop a multi-purpose strip aluminum pigment and a preparation method thereof to solve the problem that aluminum pigment products in the prior art cannot be used for multiple purposes. Summary of the invention

[0006] The object of the present invention is to provide a multi-purpose strip aluminum pigment and a preparation method thereof. The specific technical scheme is as follows:

[0007] In a first aspect, the present invention provides a method for preparing a multi-purpose strip aluminum pigment, comprising:

[0008] Step S1, adding an alcohol solvent or an alcohol ether solvent to an aluminum pigment, and mixing to form a first dispersion of the aluminum pigment; adding a passivating agent to the first dispersion of the aluminum pigment to form a passivation film on the surface of the aluminum pigment; filtering the passivated aluminum pigment to form a first filter cake; drying the first filter cake to obtain a dried aluminum pigment;

[0009] Step S2, adding an alcohol solvent or an alcohol ether solvent to the aluminum pigment dried in step S1, and mixing to form a second dispersion of the aluminum pigment; heating the second dispersion of the aluminum pigment to 60-80° C., and adjusting the pH value of the second dispersion of the aluminum pigment to 6-6.5 or 8-9, adding an organic silicon coating auxiliary agent to coat the surface of the aluminum pigment to form a network silicon dioxide film; and filtering the coated aluminum pigment to form a second filter cake;

[0010] Step S3, heating and stirring the second filter cake, the re-soluble resin, the polymer wax and the antioxidant to obtain a mixed material;

[0011] Step S4, cooling the mixed material to room temperature, extruding it into strips, and drying it to obtain a multi-purpose strip aluminum pigment.

[0012] Optionally, in step S3, in terms of mass percentage, the second filter cake is 70%-80%, the re-soluble resin is 15%-18%, the polymer wax is 4%-6% and the antioxidant is 0.5%-1%.

[0013] Optionally, the re-soluble resin includes at least one of acrylic resin and urea-formaldehyde resin; the polymer wax includes at least one of polyethylene wax powder, polypropylene wax powder, oxidized polyethylene wax powder (such as BASF EVA3 wax powder) and polyester wax; the antioxidant includes at least one of antioxidant 168 and antioxidant 1010.

[0014] Optionally, in step S3, the heating and stirring treatment adopts a heating temperature of 80-100°C, a stirring time of 30-60min, and a stirring rate of 300-500rpm.

[0015] Optionally, in step S2, the amount of the organosilicon coating auxiliary agent is 4%-12% of the mass of the aluminum pigment in the second aluminum pigment dispersion;

[0016] The organosilicon coating auxiliary agent includes at least one of tetraethoxysilane, aminosiloxane and 3-aminopropyltriethoxysilane.

[0017] Optionally, in step S2, an acid solution is used to adjust the pH value to 6-6.5; the acid solution includes ammonium chloride solution or oxalic acid solution; an alkali solution is used to adjust the pH value to 8-9; the alkali solution includes one or more of an ammonia solution, ethylenediamine and monoethanolamine.

[0018] Optionally, in step S1 and step S2, the alcohol solvent includes anhydrous ethanol, n-propanol or isopropanol; the alcohol ether solvent includes propylene glycol methyl ether or ethylene glycol butyl ether;

[0019] The solid contents of the first filter cake and the second filter cake are both 75%-80%.

[0020] Optionally, in step S1, the amount of the passivator is 4%-6% of the mass of the aluminum pigment in the first dispersion of the aluminum pigment; the passivator includes a silicone-modified acrylic resin (such as Wanxia New Materials WX-S1578F) surface passivator or a phosphate ester (such as Haian Petrochemical Phosphate NP-4P) surface passivator.

[0021] Optionally, in step S4, the drying temperature used in the drying treatment is 70-80°C; and the solvent mass content of the multi-purpose strip aluminum pigment obtained after the drying treatment is less than or equal to 0.5%.

[0022] In a second aspect, the present invention provides a multi-purpose strip aluminum pigment, which is prepared by the preparation method of the multi-purpose strip aluminum pigment.

[0023] The application of the technical solution of the present invention has at least the following beneficial effects:

[0024] The present invention provides a method for preparing a multi-purpose strip aluminum pigment. In step S1, a passivating agent is added to the first dispersion of the aluminum pigment to form a passivating film on the surface of the aluminum pigment, that is, the surface of the aluminum pigment has acid and alkali resistance, so that the aluminum pigment is protected under a slightly acidic and alkaline condition of pH 6-6.5 or 8-9 in step S2; and an organic silicon coating auxiliary agent is added under a pH value of 6-6.5 or 8-9, which is a reaction condition for coating the surface of the aluminum pigment to form a network silicon dioxide film; the coating to form a network silicon dioxide film improves the acid and alkali resistance of the surface of the aluminum pigment; in step S3, a resolvable resin is used to facilitate melting during heating and stirring, and the melted resolvable resin The lipid molecules can fill the gaps in the mesh silica film and form a stable molecular connection structure with the silica molecules, so that the aluminum pigment product has good dispersibility in various application scenarios and can be used for multiple purposes; an antioxidant is used to prevent the aluminum pigment product from oxidizing and agglomerating during the extrusion into strips and drying process in step S4; when the aluminum pigment product is used in powder coatings, polymer wax is used as a leveling agent; when the aluminum pigment product is used in plastic spray-free coatings, polymer wax is used as a dispersant; when the aluminum pigment product is used in liquid coatings and inks, polymer wax is used as an anti-settling aid; the multi-purpose strip aluminum pigment obtained by the drying process in step S4 can also meet the requirements of solvent-free and solidification. Therefore, the multi-purpose strip aluminum pigment prepared by the present invention can meet the environmental protection requirements of solvent-free and solidification, and can also be used for multiple purposes. DETAILED DESCRIPTION

[0025] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0026] Embodiment 1:

[0027] A method for preparing a multi-purpose strip aluminum pigment comprises:

[0028] Step S1, adding propylene glycol methyl ether to the aluminum pigment, stirring (stirring speed is 300rpm) to form a first dispersion of the aluminum pigment; adding a passivator (specifically silicone-modified acrylic resin, preferably Wanxia New Material WX-S1578F) to the first dispersion of the aluminum pigment, passivating for 4 hours to form a passivation film on the surface of the aluminum pigment; the amount of the passivator is 6% of the mass of the aluminum pigment in the first dispersion of the aluminum pigment; filtering the passivated aluminum pigment to form a first filter cake (the solid content of the first filter cake is 75%); drying the first filter cake in an oven to obtain a dried aluminum pigment;

[0029] Step S2, adding 3 times the mass of anhydrous ethanol to the aluminum pigment dried in step S1, stirring (stirring speed is 400 rpm) to form a second dispersion of aluminum pigment; heating the second dispersion of aluminum pigment to 60° C., and at the same time, adjusting the pH value of the second dispersion of aluminum pigment to 8-9 with an ammonia solution, adding an organosilicon coating auxiliary agent (specifically tetraethoxysilane) to coat the surface of the aluminum pigment to form a network silicon dioxide film; the amount of the organosilicon coating auxiliary agent is 10% of the mass of the aluminum pigment in the second dispersion of aluminum pigment; filtering the coated aluminum pigment to form a second filter cake (the solid content of the second filter cake is 80%);

[0030] Step S3, by mass percentage, 80% of the second filter cake, 13% of the resoluble resin (specifically acrylic resin), 6% of the polymer wax (specifically polyethylene wax powder) and 1% of the antioxidant (specifically antioxidant 1010) are put into a kneader, and heated and stirred to obtain a mixed material; the heating and stirring treatment adopts a heating temperature of 100° C., a stirring time of 30 minutes, and a stirring rate of 350 rpm;

[0031] Step S4, cooling the mixed material to room temperature and placing it in an extruder, extruding it into strips, and drying it to obtain a multi-purpose strip aluminum pigment; the drying temperature used in the drying treatment is 70°C, and the drying time is 10 hours; the solvent mass content of the multi-purpose strip aluminum pigment obtained after the drying treatment is less than or equal to 0.5%.

[0032] Embodiment 2:

[0033] The difference from Example 1 is that in step S1, n-propanol is added to the aluminum pigment to form a first dispersion of the aluminum pigment; the passivator is a phosphate surface passivator (specifically Haian Petrochemical Phosphate NP-4P), and its amount is 4% of the mass of the aluminum pigment in the first dispersion of the aluminum pigment; the passivation treatment is performed for 3 hours; in step S2, the amount of the organosilicon coating auxiliary agent is 11% of the mass of the aluminum pigment in the second dispersion of the aluminum pigment, wherein the organosilicon coating auxiliary agent is 1% of aminosiloxane and 10% of tetraethoxysilane; in step S3, the polymer wax is polyester wax, and the amount is 4%; the amount of acrylic resin is 15%; the heating temperature used in the heating and stirring treatment is 80°C.

[0034] Embodiment 3:

[0035] Different from Example 1, in step S1, the passivator is a phosphate surface passivator (specifically Haian Petrochemical Phosphate NP-4P), and its dosage is 4% of the mass of the aluminum pigment in the first dispersion of the aluminum pigment, and the passivation treatment is carried out for 3 hours; in step S2, the pH value of the second dispersion of the aluminum pigment is adjusted to 6-6.5 using oxalic acid solution; the dosage of the organosilicon coating auxiliary agent is 4% of the mass of the aluminum pigment in the second dispersion of the aluminum pigment, wherein the organosilicon coating auxiliary agent is 3-aminopropyltriethoxysilane; in step S3, the re-soluble resin is urea-formaldehyde resin, and its dosage is 15%; the polymer wax is polyester wax, and the dosage is 4.5%; the dosage of the antioxidant is 0.5%; the heating temperature used in the heating and stirring treatment is 90°C; and the drying temperature used in the drying treatment in step S4 is 75°C.

[0036] Embodiment 4:

[0037] Different from Example 1, in step S1, the amount of the passivator is 4% of the mass of the aluminum pigment in the first aluminum pigment dispersion, and the passivation treatment is carried out for 3 hours; in step S2, ammonium chloride solution is used to adjust the pH value of the second aluminum pigment dispersion to 6-6.5; the amount of the silicone coating auxiliary agent is 12% of the mass of the aluminum pigment in the second aluminum pigment dispersion, wherein the silicone coating auxiliary agent is 2% of 3-aminopropyltriethoxysilane and 10% of tetraethoxysilane; in step S3, the re-soluble resin is urea-formaldehyde resin, and its amount is 15%; the polymer wax is polyester wax, and the amount is 4%; the heating temperature used in the heating and stirring treatment is 80°C; and the drying temperature used in the drying treatment in step S4 is 75°C.

[0038] Comparative Example 1:

[0039] The difference from Example 1 is that the amount of passivating agent used is zero.

[0040] Comparative Example 2:

[0041] Different from Example 1, the amount of organic silicon coating auxiliary agent used is zero and the amount of ammonia solution used is zero.

[0042] Comparative Example 3:

[0043] The difference from Example 1 is that the amount of the re-soluble resin is zero.

[0044] Comparative Example 4:

[0045] The difference from Example 1 is that the resolubilizing resin is replaced by a thermosetting resin (specifically epoxy resin).

[0046] Take out 4 portions of the multi-purpose strip aluminum pigment prepared in Examples 1-4 and Comparative Examples 1-4, respectively, and make ink products, liquid coating products, powder coating products and plastic spray-free products accordingly, and conduct use tests. The test results are shown in Table 1. Among them, when making ink products, the multi-purpose strip aluminum pigment and the organic solvent (specifically n-propyl ester) are mixed and dispersed evenly in a mass ratio of 1:1, and then the ink resin (specifically Andeli ADL-3066CL) with a mass of 10 times that of the multi-purpose strip aluminum pigment is added and mixed evenly. When making liquid coating products, the multi-purpose strip aluminum pigment and the organic solvent (specifically n-propyl ester) are mixed and dispersed evenly in a mass ratio of 1:1, and then the coating resin (specifically Sanmu BS985 resin) with a mass of 10 times that of the multi-purpose strip aluminum pigment is added and mixed evenly. When making powder coating products, the multi-purpose strip aluminum pigment is crushed by a crusher, and then 2% by weight of the crushed strip aluminum pigment is added to the plastic powder (specifically, CRYLCOAT 2415-2 powder coating polyester resin of Allnex), and after being mixed evenly or bonded by a bonding machine, the powder coating product is obtained. When making plastic spray-free products, the multi-purpose strip aluminum pigment and plastic particles are mixed at a mass ratio of 2:98, and then extruded by an injection molding machine to obtain a plastic spray-free product.

[0047] Table 1 Test results of multi-purpose strip aluminum pigments

[0048]

[0049]

[0050] It can be seen from the data in Table 1 that, compared with Comparative Examples 1-4, the multi-purpose strip aluminum pigments prepared by Examples 1-4 of the present invention have good performance in making ink products, liquid coating products, powder coating products and plastic spray-free products.

[0051] By comparing Example 1 and Comparative Example 1, it can be seen that the multi-purpose strip aluminum pigment prepared by using zero amount of passivator does not form a passivation film on the surface of the aluminum pigment, which makes the surface of the aluminum pigment easily corroded, reduces the aluminum content, and further reduces the hiding power of the aluminum pigment when used in ink products; in addition, the corrosion of the aluminum pigment surface makes the aluminum pigment surface rough, which reduces the gloss of the aluminum pigment used in liquid coating products, powder coating products and plastic spray-free products.

[0052] By comparing Example 1 and Comparative Example 2, it can be seen that the multi-purpose strip aluminum pigment prepared by using zero amount of silicone coating auxiliary agent and zero amount of ammonia solution does not form a silicon dioxide film on the surface of the aluminum pigment, which reduces its acid and alkali resistance, resulting in reduced acid and alkali resistance of the aluminum pigment when used in powder coating products; in addition, no silicon dioxide film is formed on the surface of the aluminum pigment, which reduces its coupling performance with external substances, resulting in reduced adhesion of the aluminum pigment when used in ink products, liquid coating products and powder coating products.

[0053] By comparing Example 1 and Comparative Example 3, it can be seen that the multi-purpose strip aluminum pigment prepared by using zero amount of re-soluble resin has poor dispersibility when used in ink products and liquid coating products, which easily leads to agglomeration between aluminum pigment particles, resulting in larger particle size of aluminum pigment particles, reduced hiding power and reduced gloss.

[0054] By comparing Example 1 and Comparative Example 4, it can be seen that the multi-purpose strip aluminum pigment prepared by using epoxy resin has no solubility, which reduces its dispersion performance, adhesion, hiding power, glossiness and compatibility in ink products, liquid coating products, powder coating products and plastic spray-free products.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a multi-purpose strip aluminum pigment, characterized in that: include: Step S1, adding an alcohol solvent or an alcohol ether solvent to an aluminum pigment, and mixing to form a first dispersion of the aluminum pigment; adding a passivating agent to the first dispersion of the aluminum pigment to form a passivation film on the surface of the aluminum pigment; filtering the passivated aluminum pigment to form a first filter cake; drying the first filter cake to obtain a dried aluminum pigment; Step S2, adding an alcohol solvent or an alcohol ether solvent to the aluminum pigment dried in step S1, and mixing to form a second dispersion of the aluminum pigment; heating the second dispersion of the aluminum pigment to 60-80° C., and adjusting the pH value of the second dispersion of the aluminum pigment to 6-6.5 or 8-9, adding an organic silicon coating auxiliary agent to coat the surface of the aluminum pigment to form a network silicon dioxide film; and filtering the coated aluminum pigment to form a second filter cake; Step S3, heating and stirring the second filter cake, the re-soluble resin, the polymer wax and the antioxidant to obtain a mixed material; Step S4, cooling the mixed material to room temperature, extruding it into strips, and drying it to obtain a multi-purpose strip aluminum pigment.

2. The method for preparing the multi-purpose strip aluminum pigment according to claim 1, characterized in that: In step S3, in terms of mass percentage, the second filter cake is 70%-80%, the re-soluble resin is 15%-18%, the polymer wax is 4%-6% and the antioxidant is 0.5%-1%.

3. The method for preparing the multi-purpose strip aluminum pigment according to claim 1, characterized in that: The re-soluble resin includes at least one of acrylic resin and urea-formaldehyde resin; the polymer wax includes at least one of polyethylene wax powder, polypropylene wax powder, oxidized polyethylene wax powder and polyester wax; the antioxidant includes at least one of antioxidant 168 and antioxidant 1010.

4. The method for preparing the multi-purpose strip aluminum pigment according to claim 1, characterized in that: In step S3, the heating and stirring treatment adopts a heating temperature of 80-100°C, a stirring time of 30-60 minutes, and a stirring speed of 300-500 rpm.

5. The method for preparing the multi-purpose strip aluminum pigment according to claim 1, characterized in that: In step S2, the amount of the organosilicon coating auxiliary agent is 4%-12% of the mass of the aluminum pigment in the second aluminum pigment dispersion; The organosilicon coating auxiliary agent includes at least one of tetraethoxysilane, aminosiloxane and 3-aminopropyltriethoxysilane.

6. The method for preparing the multi-purpose strip aluminum pigment according to claim 1, characterized in that: In step S2, an acid solution is used to adjust the pH value to 6-6.5; the acid solution includes ammonium chloride solution or oxalic acid solution; an alkali solution is used to adjust the pH value to 8-9; the alkali solution includes one or more of ammonia solution, ethylenediamine and monoethanolamine.

7. The method for preparing the multi-purpose strip aluminum pigment according to claim 1, characterized in that: In step S1 and step S2, the alcohol solvent includes anhydrous ethanol, n-propanol or isopropanol; the alcohol ether solvent includes propylene glycol methyl ether or ethylene glycol butyl ether; The solid contents of the first filter cake and the second filter cake are both 75%-80%.

8. The method for preparing the multi-purpose strip aluminum pigment according to claim 1, characterized in that: In step S1, the amount of the passivator is 4%-6% of the mass of the aluminum pigment in the first aluminum pigment dispersion; the passivator includes an organic silicon modified acrylic resin surface passivator or a phosphate ester surface passivator.

9. The method for preparing the multi-purpose strip aluminum pigment according to claim 1, characterized in that: In step S4, the drying temperature used in the drying process is 70-80° C.; after the drying process, the solvent mass content of the multi-purpose strip aluminum pigment obtained is less than or equal to 0.5%.

10. A multi-purpose strip aluminum pigment, characterized in that: The multi-purpose strip aluminum pigment is prepared by the preparation method according to any one of claims 1 to 9.

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