Odorless aluminum pigment and preparation method thereof

Abstract

The invention relates to the technical field of aluminum pigments, in particular to an odorless aluminum pigment and a preparation method thereof. The aluminum pigment comprises the following raw material components in percentage by mass: 60%-65% of spherical aluminum powder, 30%-35% of a carrier solvent, 1%-2% of a grinding aid and 0.5%-1% of a dispersing agent, the carrier solvent comprises isoparaffin; the grinding aid comprises at least one of lauric acid and derivatives thereof, a fatty acid silane coupling agent, a phthalic ester coupling agent, polyamide wax and stearic acid. The method can be used for preparing the aluminum pigment. According to the prepared aluminum pigment, under the condition that it can be ensured that the metal effect performance is not changed or even improved, the control over the odor of the aluminum pigment can reach the standard.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum pigments, and particularly relates to an odorless aluminum pigment and a preparation method thereof. Background Art

[0002] In the industries of ink coatings and color masterbatch spray-free, aluminum pigments are required as metal effect filling materials. Since a large number of ink coatings are printed on the inner and outer packaging materials of food, the main downstream industries of the color masterbatch spray-free industry include shoe materials, home appliance panels, and various plastic blown films, etc. All of these require high-standard odor control for aluminum pigments. At present, in terms of odor control of aluminum pigments, the industries of ink coatings and color masterbatch spray-free require that aluminum pigments are solvent-free or odorless. However, existing aluminum pigment products contain carrier solvents. Among them, commonly used carrier solvents include aromatic hydrocarbons or decalin-free tetramethylbenzene solvents, resulting in the aluminum pigment products having pungent odors and failing to meet the odor control standards.

[0003] In summary, it is necessary to develop an odorless aluminum pigment and a preparation method thereof to solve the problem that the existing aluminum pigments fail to meet the odor control standards while ensuring that the metal effect performance of the aluminum pigments remains unchanged or even improved. Summary of the Invention

[0004] The purpose of the present invention is to provide an odorless aluminum pigment and a preparation method thereof. The specific technical solutions are as follows:

[0005] In the first aspect, the present invention provides an odorless aluminum pigment, which comprises the following raw material components in mass percentages: 60% - 65% of spherical aluminum powder, 30% - 35% of carrier solvent, 1% - 2% of grinding aid, and 0.5% - 1% of dispersant;

[0006] The carrier solvent comprises isoparaffin;

[0007] The grinding aid comprises at least one of lauric acid and its derivatives, fatty acid silane coupling agent, phthalate coupling agent, polyamide wax, and stearic acid.

[0008] Optionally, the dispersant comprises dispersant 4300.

[0009] Optionally, the lauric acid and its derivatives comprise model LG110.

[0010] Optionally, the fatty acid silane coupling agent comprises Dow Corning 6008.

[0011] Optionally, the phthalate coupling agent comprises model YB508.

[0012] Optionally, the particle size of the spherical aluminum powder is 1 - 21 μm.

[0013] Optionally, the grinding aid includes at least one of phthalate coupling agent and stearic acid.

[0014] In a second aspect, the present invention provides a method for preparing the odorless aluminum pigment, which includes mixing spherical aluminum powder, carrier solvent, grinding aid and dispersant in required mass percentages, and then grinding with grinding media to obtain.

[0015] Optionally, the grinding media includes steel balls or glass beads.

[0016] Optionally, the grinding time is 28 - 40 h.

[0017] Applying the technical solution of the present invention has at least the following beneficial effects:

[0018] An odorless aluminum pigment provided by the present invention can achieve compliance with the odor control standard of aluminum pigment while ensuring that the metallic effect performance remains unchanged or even improved. Specifically:

[0019] On the one hand, the carrier solvent adopted by the present invention is isoparaffin with low odor, and its molecular structure is relatively stable. From the perspective of intermolecular forces, there are mainly weak van der Waals forces between isoparaffin and aluminum pigment particles, enabling isoparaffin to uniformly wrap the aluminum pigment particles, thereby reducing the volatilization of odor substances in the aluminum pigment itself. At the same time, due to the weak van der Waals forces, it will not have a significant impact on the crystal structure of the aluminum pigment and the surface electron cloud distribution. And the metallic effect performance of the aluminum pigment largely depends on the reflection, scattering, etc. of its crystal structure and surface electron cloud on light, so the metallic effect performance will not be damaged.

[0020] On the other hand, the grinding aid adopted by the present invention includes at least one of lauric acid and its derivatives, fatty acid silane coupling agent, phthalate coupling agent, polyamide wax and stearic acid; among them, the molecules of lauric acid and its derivatives contain active groups such as carboxyl groups, and these active groups can chemically react with some aluminum atoms on the surface of the aluminum pigment to form chemical bonds. For example, the oxygen atom in the carboxyl group can form a coordination bond with the aluminum atom to construct an organic protective film on the surface of the aluminum pigment; this organic protective film can not only prevent the volatilization of impurities that produce odor inside the aluminum pigment, but also because of its certain flexibility and chemical stability, it will not change the microscopic roughness of the surface of the aluminum pigment; when light irradiates, the aluminum pigment can still efficiently reflect and scatter light by virtue of its original crystal structure and surface characteristics, maintaining good metallic effect performance;

[0021] Fatty acid silane coupling agent molecules have a special structure. One end is a silicon oxy group that is inorganic-philic, and the other end is a long carbon-hydrogen chain that is organic-philic. The silicon oxy group undergoes a condensation reaction with the hydroxyl groups on the surface of the aluminum pigment and firmly anchors on the surface of the aluminum pigment, while the carbon-hydrogen long chain extends outward and has good compatibility with the surrounding organic medium (such as isoparaffin, etc.). This structure not only makes the dispersion of the aluminum pigment more stable, avoiding the reduction of the metallic effect performance due to agglomeration, but also can form a stable interfacial layer on the surface of the aluminum pigment to prevent the escape of odor substances;

[0022] In the phthalate coupling agent molecule, the phthalate group can undergo physical adsorption and chemical action with the surface of the aluminum pigment. Specifically, the oxygen atom in the phthalate group forms a weak chemical bond or coordination bond with the aluminum atom, forming a coating layer on the surface of the aluminum pigment. This coating layer can not only prevent the escape of odor substances but also does not change the optical properties of the aluminum pigment, and thus does not affect the metallic effect performance;

[0023] The amide group in the polyamide wax molecule has a certain polarity and can interact with the polar sites on the surface of the aluminum pigment to produce physical adsorption. As a result, the polyamide wax can form a protective network around the aluminum pigment particles. This protective network can not only limit the movement of the aluminum pigment particles but also reduce the structural damage caused by collisions, thereby maintaining the metallic effect performance. Moreover, this protective network serves as a physical barrier to prevent the diffusion of odor substances inside the aluminum pigment;

[0024] Stearic acid is a low-odor saturated fatty acid and can evenly adhere to the surface of the aluminum pigment during grinding. On the one hand, it prevents the diffusion of odor substances inside the aluminum pigment. On the other hand, it isolates the aluminum pigment from contact with external oxygen to avoid oxidation of the aluminum pigment, thereby maintaining the metallic effect performance. On the other hand, it can also improve the lubrication effect between aluminum pigments, avoid agglomeration, and further maintain the metallic effect performance.

[0025] On the other hand, the present invention combines the use of a carrier solvent and a grinding aid, which can synergistically ensure that the metallic effect performance of the aluminum pigment remains unchanged or even improved while achieving compliance with odor control. Specifically, the present invention combines the use of a carrier solvent and a grinding aid, which can form various chemical bonds and / or physical protective layers on the surface of the aluminum pigment, synergistically preventing the volatilization of the odor of the aluminum pigment and achieving compliance with odor control of the aluminum pigment. And the various chemical bonds and / or physical protective layers do not have a negative impact on the physical structure and optical properties of the aluminum pigment, and the metallic effect performance is maintained. Moreover, the combination of various chemical bonds or protective layers and a dispersant can promote the uniform dispersion of the aluminum pigment. The uniformly dispersed aluminum pigment reflects and scatters light more uniformly and efficiently, and the metallic effect performance is enhanced. Specific Embodiments

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0027] Example 1:

[0028] An odorless aluminum pigment is prepared as follows:

[0029] Mix the spherical aluminum powder (particle size 1 - 21 μm) with the required mass percentage, carrier solvent (specifically isoparaffin), grinding aid (specifically stearic acid), and dispersant (specifically dispersant 4300, i.e., ethoxylated tridecyl alcohol phosphate), and then grind with steel balls for 40 h to obtain; among them, the mass percentage of spherical aluminum powder is 63%, the mass percentage of carrier solvent is 34%, the mass percentage of grinding aid is 2%, and the mass percentage of dispersant is 1%.

[0030] Example 2:

[0031] Different from Example 1, stearic acid is replaced with a phthalate coupling agent, and the phthalate coupling agent is specifically type YB508.

[0032] Example 3:

[0033] Different from Example 1, stearic acid is replaced with lauric acid and its derivatives, and the lauric acid and its derivatives are specifically type LG110.

[0034] Example 4:

[0035] Different from Example 1, stearic acid is replaced with a fatty acid silane coupling agent, and the fatty acid silane coupling agent is specifically Dow Corning 6008.

[0036] Example 5:

[0037] Different from Example 1, stearic acid is replaced with polyamide wax.

[0038] Comparative Example 1:

[0039] Different from Example 1, stearic acid is replaced with oleic acid.

[0040] Comparative Example 2:

[0041] Different from Example 1, isoparaffin is replaced with paraffin oil.

[0042] Comparative Example 3:

[0043] Different from Example 1, isoparaffin is replaced with white oil.

[0044] Comparative Example 4:

[0045] Different from Example 1, the isoparaffin was replaced with an ester substance, specifically polymethyl methacrylate.

[0046] Comparative Example 5:

[0047] Different from Example 1, the isoparaffin was replaced with an ether substance, specifically ethylene glycol monobutyl ether.

[0048] Comparative Example 6:

[0049] Different from Example 1, the isoparaffin was replaced with an alcohol substance, specifically polyethylene glycol.

[0050] The aluminum pigments prepared in Examples 1 to 5 and Comparative Examples 1 to 6 were respectively subjected to odor tests and gloss tests. The test results are shown in Table 1. The odor test method is as follows: Weigh 30 mL of the aluminum pigment sample in a 50 mL beaker, gently wave your hand over the beaker mouth, and use your sense of smell to test the odor of the aluminum pigment. The gloss test method is as follows: Use the method for measuring the gloss of paint and varnish films specified in GB / T 9754-2007 "Determination of 20°, 60° and 85° specular gloss of paint films without metallic pigments of paints and varnishes", which can be used to evaluate the gloss characteristics of metal surface coatings.

[0051] Table 1 Odor and gloss test results

[0052]

[0053]

[0054] From the data in Table 1, it can be seen that compared with Comparative Examples 1 to 6, the aluminum pigments prepared in Examples 1 to 5 of the present invention not only have no obvious odor, but also the L value of the gloss is relatively increased. This shows that the combined use of the carrier solvent and the grinding aid in the present invention can synergistically ensure that the metal effect performance of the aluminum pigment remains unchanged or even improved, and at the same time can achieve the standard of odor control.

[0055] In addition, by comparing Example 1 and Comparative Example 1, it is known that when stearic acid is replaced with oleic acid, oleic acid is prone to rancidity, which not only makes the aluminum pigment produce a pungent smell, but also reduces the shelf life of the aluminum pigment; moreover, after the oleic acid becomes rancid, the protective effect on the aluminum pigment is significantly reduced, resulting in an aggravation of the agglomeration phenomenon between aluminum pigment particles, leading to a decrease in the L value of the gloss and a reduction in the metal effect performance.

[0056] By comparing Example 1 and Comparative Example 2, it can be seen that when isoparaffin is replaced with paraffin oil, paraffin oil is prone to spoilage, which not only makes the aluminum pigment have a pungent smell, but also reduces the shelf life of the aluminum pigment. Moreover, after the paraffin oil spoils, the protective effect on the aluminum pigment is significantly reduced, resulting in an aggravation of the agglomeration phenomenon between aluminum pigment particles, leading to a decrease in the L value of gloss and a reduction in the metallic effect performance.

[0057] By comparing Example 1 and Comparative Example 3, it can be seen that although replacing isoparaffin with white oil can also achieve the standard of controlling the odor of the aluminum pigment, the viscosity of white oil is high, and it is difficult to control the screening process and the solid-liquid separation process during the preparation of the aluminum pigment, resulting in a decrease in the L value of gloss and a reduction in the metallic effect performance of the aluminum pigment.

[0058] By comparing Example 1 and Comparative Examples 4 to 6, it can be seen that when isoparaffin is replaced with ester substances, ether substances, and alcohol substances, although the odor control of the aluminum pigment can meet the standard, the closed cup flash points of ester substances, ether substances, and alcohol substances are relatively low, and there are safety hazards during the grinding process. However, the closed cup flash point of the isoparaffin used in Example 1 is relatively high, and the aluminum pigment can be safely ground and prepared. Moreover, the water content in ester substances, ether substances, and alcohol substances is high, and they are prone to react with the aluminum pigment, resulting in a decrease in the L value of gloss and a reduction in the metallic effect performance.

[0059] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An odorless aluminum pigment, characterized in that, The raw material components include the following mass percentages: 60% - 65% of spherical aluminum powder, 30% - 35% of carrier solvent, 1% - 2% of grinding aid, and 0.5% - 1% of dispersant; The carrier solvent includes isoparaffin; The grinding aid includes at least one of lauric acid and its derivatives, fatty acid silane coupling agent, phthalate coupling agent, polyamide wax, and stearic acid.

2. The odorless aluminum pigment according to claim 1, characterized in that, The dispersant includes Dispersant 4300.

3. The odorless aluminum pigment according to claim 1, wherein The lauric acid and its derivatives include Model LG110.

4. The odorless aluminum pigment according to claim 1, characterized in that, The fatty acid silane coupling agent includes Dow Corning 6008.

5. The odorless aluminum pigment according to claim 1, wherein The phthalate coupling agent includes Model YB508.

6. The odorless aluminum pigment according to claim 1, wherein The particle size of the spherical aluminum powder is 1 - 21 μm.

7. The odorless aluminum pigment according to any one of claims 1 to 6, characterized in that, The grinding aid includes at least one of phthalate coupling agent and stearic acid.

8. A method for preparing an odorless aluminum pigment as described in claim 7, characterized in that, It is prepared by mixing the spherical aluminum powder, carrier solvent, grinding aid, and dispersant with the required mass percentages and then grinding with grinding media.

9. The method for preparing an odorless aluminum pigment according to claim 8, characterized in that, The grinding media includes steel balls or glass beads.

10. The preparation method of the odorless aluminum pigment according to claim 8, characterized in that, The grinding time is 28 - 40 h.

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