A metal aluminum pigment for spray-free use with embrittlement performance and its preparation method

Abstract

The present invention discloses a metal aluminum pigment for spray-free use with embrittlement performance and a preparation method thereof. The metal aluminum pigment for spray-free use is prepared from raw materials with the following weight percentage contents: 60%-75% of metal aluminum pigment, 20%-35% of epoxy resin, 2%-6% of diffusion powder, and 3%-5% of embrittling agent. By adding the embrittling agent, the pigment after granulation and drying is more easily broken, greatly shortening the breaking time of the pigment in the pulverizer, effectively preserving the shape of the metal aluminum flakes in the metal aluminum pigment for spray-free use, reducing the color difference of injection-molded products, improving the aesthetics of injection-molded products, and also reducing the production cost. At the same time, the appearance size of the broken pigment can be made uniform, and it is more uniform when mixed with plastic particles.

Description

Technical Field

[0001] The present invention relates to the technical field of paints for spray-free use, and particularly to a spray-free metallic aluminum paint with embrittlement performance that can reduce the paint breaking time and a preparation method thereof. Background Art

[0002] At present, the outer shells of household appliances and the interior parts of automobiles usually spray a layer of paint on the surface of plastic or metal parts to meet the different needs of consumers. However, most of the paints on the current market contain volatile substances harmful to the body, such as benzene and aldehydes. In the spraying process, these chemical substances will volatilize, not only causing great pollution to the environment, but also causing great harm to the bodies of the spraying personnel in the long term. Especially when processing some high-grade products, the requirements for the spraying process are relatively high, which will inevitably lead to an increase in the defective rate of spraying, thereby increasing the cost of the spraying process. In this scenario, some domestic companies have developed paints for spray-free use. This spray-free paint is premixed with plastic particles (such as PP, ABS, etc.) during injection molding, and then melt-mixed and directly injection-molded into colored products. In order to make the spray-free paint and plastic particles mix as evenly as possible, it is necessary to first break the spray-free paint into fine particles. On the one hand, the breaking process will increase the production cost. On the other hand, the breaking process takes a long time, and the high-intensity external force shear will damage the metallic aluminum sheet raw materials in the spray-free paint, resulting in color differences in the injection-molded products and affecting the appearance.

[0003] Therefore, how to overcome the defect that the existing spray-free metallic aluminum paint has a long breaking time, resulting in shear damage to the metal raw materials in the paint, is an urgent problem to be solved in the industry. Summary of the Invention

[0004] The present invention provides a spray-free metallic aluminum paint with embrittlement performance that can reduce the paint breaking time and a preparation method thereof to solve the technical problem that the existing spray-free metallic aluminum paint has a long breaking time during the breaking process, resulting in shear damage to the metal raw materials in the paint.

[0005] The present invention provides a spray-free metallic aluminum paint with embrittlement performance, which is prepared from the following raw materials in percentage by weight: 60%-75% of metallic aluminum paint, 20%-35% of epoxy resin, 2%-6% of diffusion powder, and 3%-5% of embrittling agent.

[0006] Preferably, the metallic aluminum paint is a flaky aluminum paint prepared by ball milling aluminum powder; the weight ratio of metallic aluminum in the aluminum paint is 70%-80%, petroleum solvent and additives account for 20%-30%, and the particle size of the aluminum paint is between 5um and 50um.

[0007] Preferably, the epoxy resin is one of modified PP, modified ABS or modified polyurethane.

[0008] Preferably, the diffusion powder is a waxy amide.

[0009] Preferably, the embrittling agent is at least one of NaF, Al2O3, mica or glass powder.

[0010] The present invention also provides a method for preparing a metal aluminum pigment for spray-free use with embrittling properties, and the steps are as follows.

[0011] Step 1: Weigh various raw materials for preparing the metal aluminum pigment for spray-free use according to the ratio, and pre-add the embrittling agent and diffusion powder into the metal aluminum pigment and stir for 0.5 h to obtain a mixture.

[0012] Step 2: Then add the epoxy resin into the mixture, heat it to 110 - 150 °C and carry out co-melting for 2 - 3 h to obtain a co-melted mixture.

[0013] Step 3: When the co-melted mixture is cooled to 60 - 80 °C, granulate it to obtain the metal aluminum pigment for spray-free use.

[0014] Preferably, after baking the metal aluminum pigment particles for spray-free use for 7 hours, crush them, and the baking temperature is 80 °C.

[0015] Preferably, in Step 2, after adding a petroleum solvent with a wetting effect to the mixture, then carry out the heating co-melting; the dosage of the petroleum solvent is less than 1% of the total amount of the metal aluminum pigment for spray-free use.

[0016] Preferably, after adding the petroleum solvent, stir and mix for 5 minutes first, and then carry out the heating co-melting.

[0017] By adding an embrittling agent, the present invention can make the pigment after granulation and drying easier to crush, which can greatly reduce the crushing time of the metal aluminum pigment for spray-free use in the crusher, effectively preserve the shape of the metal aluminum flakes in the metal aluminum pigment for spray-free use, reduce the color difference of the injection-molded products, improve the aesthetic degree of the injection-molded products, and also reduce the production cost. At the same time, it can also make the appearance size of the crushed pigment uniform and more uniform when mixed with plastic particles. Description of the Drawings

[0018] Figure 1 Comparison diagram of the particles after crushing the metal aluminum pigment for spray-free use prepared in Preparation Example 1 and the prior art;

[0019] Figure 2 Comparison diagram of the particles after crushing the metal aluminum pigment for spray-free use prepared in Preparation Example 2 and the prior art;

[0020] Figure 3 Comparison chart of the particles after crushing of the metal aluminum pigment for spray-free use prepared in Preparation Example 3 and the prior art. Detailed implementation manners

[0021] A metal aluminum pigment for spray-free use with embrittlement performance proposed by the present invention is prepared from raw materials with the following weight percentage contents: 60%-75% of metal aluminum pigment, 20%-35% of epoxy resin, 2%-6% of diffusion powder, and 3%-5% of embrittling agent. Among them: the metal aluminum pigment is a flaky aluminum pigment prepared by ball milling aluminum powder; the weight ratio of metallic aluminum in this aluminum pigment is 70%-80%, and petroleum solvent and additives account for 20%-30%. Usually, more aluminum pigment particles have a particle size between 5um and 50um, and the metal aluminum pigment plays a role in coloring and covering. The epoxy resin is one of modified PP, modified ABS, or modified polyurethane, etc. The epoxy resin can help the pigment disperse better and reduce the generation of flow marks and weld lines during the injection molding process. The diffusion powder is a waxy amide, which has processing lubrication and low-temperature anti-sticking effects on polymer resins and can prevent the resin melt from adhering to the metal surface. The embrittling agent is a kind of inorganic compound, such as one or a mixture of several raw materials among NaF, Al2O3, mica, or glass powder. The role of the embrittling agent is to reduce the toughness of the product after drying, making it easier to break during the crushing process.

[0022] According to needs, metal aluminum pigments for spray-free use with embrittlement performance can be prepared with different raw material ratios. The following are the formulations of five embodiments given in the table, but it is not limited to only these five embodiments:

[0023]

[0024] The present invention also provides a preparation method of a metal aluminum pigment for spray-free use with embrittlement performance, and its steps are as follows:

[0025] First, add the embrittling agent and the diffusion powder to the metal aluminum pigment and stir for 0.5h; then add the epoxy resin and stir, and heat to 110-150°C for 2-3h of co-melting; when cooling to 60-80°C, granulate and dry.

[0026] Preparation Example 1:

[0027] A preparation method of a metal aluminum pigment for spray-free use with embrittlement performance, and its steps are as follows:

[0028] 1. Adopt the raw material ratio of Example 1 in the above-mentioned formula table of the metal aluminum pigment for spray-free use, that is, weigh the dosage of the raw materials:

[0029] 60% of metal aluminum pigment (5um), 30% of modified ABS resin, 6% of diffusion powder, 3% of mica, and 1% of NaF.

[0030] 2. Add metallic aluminum pigment, embrittler, and diffusion powder into a kneader in sequence, and premix for 30 minutes to obtain a mixture.

[0031] 3. Then add modified ABS resin, and then add petroleum solvent. This petroleum solvent is a type of environmentally friendly mineral oil, such as Mobil hydrocarbon cleaning agents D40, D60, D80, etc. The petroleum solvent plays a role in dilution and wetting, is volatile, and does not participate in physical and chemical reactions.

[0032] During the stirring process of the kneader used in production, the high-intensity shear force will damage the structure of aluminum flakes. To reduce this damage, some petroleum solvent is added. In this way, when the resin inside the product melts after heating, it will become a fluid, and stirring in the fluid is gentler than stirring at high viscosity. The added solvent ultimately needs to be dried and removed, and the addition amount should not be too much, as long as the product can remain in a fluid state after melting. Generally, the addition amount of petroleum solvent is less than 1% of the total amount of the metallic aluminum pigment for spray-free use.

[0033] 4. After stirring and mixing the mixture for 5 minutes, start the machine to heat, set the temperature to 140 °C, and heat and stir for 2 hours to obtain a molten mixture. Cool the molten mixture to 80 °C for pelletizing. The metallic aluminum pigment for spray-free use is prepared.

[0034] 5. After drying in an oven at 80 °C for 7 hours, crush it with a crusher to obtain the powder of the metallic aluminum pigment for spray-free use.

[0035] In order not to generate any VOC during injection molding, when the metallic aluminum pigment for spray-free use of the present invention is supplied to customers for use, generally the solvent in the product is first dried and recovered, that is, baked and crushed, so that no VOC will be generated during use.

[0036] As Figure 1 shown, the detection and comparison schematic diagram of the metallic aluminum pigment for spray-free use. Figure 1 On the left side in Figure 1 is the appearance shape of the existing metallic aluminum pigment for spray-free use after crushing, and on the right side in

[0037] is the effect of the metallic aluminum pigment for spray-free use of the present invention crushed under the same conditions. Obviously, the particles of the metallic aluminum pigment for spray-free use after adding the embrittler of the present invention are finer and more uniform, and can be more evenly mixed with plastic particles during use.In order to more directly reflect the changes in the size and thickness of the metal aluminum pigment for spray-free use before and after crushing, 10 samples are randomly selected from 5 batches of products in the production sample, and their particle sizes are measured. The instrument used for measurement is the BETTER BT-2900 dry image particle size and shape analyzer. As a result of the measurement, the average particle size of the existing metal aluminum pigment for spray-free use after crushing is 2637.7 um, while the average particle size of the metal aluminum pigment for spray-free use of the present invention after crushing is 1120.6 um.

[0038]

[0039] The particle size in the table refers to the size of the particles. Usually, the particle size of spherical particles is expressed by the diameter, and the particle size of cubic particles is expressed by the side length. For irregular particles, the diameter of a certain sphere with the same behavior as the particle can be used as the equivalent diameter of the particle, and the size of the particle size is commonly expressed by D50. For example, D50 = 2000um means that 50% of the particles in the sample taken are below this value, and 50% of the particles are above this value.

[0040] Preparation Example 2:

[0041] Adopt the raw material ratio of Example 2 in the above-mentioned metal aluminum pigment formula for spray-free use, that is, weigh the dosage of the raw materials:

[0042] Metal aluminum pigment (15um) 68%, modified ABS resin 27%, diffusion powder 2%, mica 1% and Al2O3 2%.

[0043] The following steps for preparing the metal aluminum pigment for spray-free use are the same as those in Preparation Example 1.

[0044] As Figure 2 shown, the detection and comparison schematic diagram of the metal aluminum pigment for spray-free use. Figure 2 The left figure in it is the appearance shape of the existing metal aluminum pigment for spray-free use after crushing, Figure 2 The right figure in it is the effect of the metal aluminum pigment for spray-free use of the present invention crushed under the same conditions. Obviously, the metal aluminum pigment particles for spray-free use after adding the embrittling agent of the present invention are more finely divided and uniform, and can be more evenly mixed with plastic particles during use.

[0045] In order to more directly reflect the changes in the size and thickness of the metal aluminum pigment for spray-free use before and after crushing, 10 samples are randomly selected from 5 batches of products in the production sample, and their particle sizes are measured. The instrument used for measurement is the BETTER BT-2900 dry image particle size and shape analyzer. As a result of the measurement, the average particle size of the existing metal aluminum pigment for spray-free use after crushing is 1886.3 um, while the average particle size of the metal aluminum pigment for spray-free use of the present invention after crushing is 351.1 um.

[0046]

[0047] Preparation Example 3:

[0048] Using the raw material ratio of Example 3 in the above metal aluminum pigment formulation for spray-free use, that is, weighing the amounts of raw materials:

[0049] Metal aluminum pigment (35um) 75%, modified ABS resin 20%, diffusion powder 2%, mica 2% and Al2O3 1%.

[0050] The following steps for preparing the metal aluminum pigment for spray-free use are the same as those of Preparation Example 1.

[0051] As Figure 3 shown, a schematic diagram for detecting and comparing the metal aluminum pigment for spray-free use. Figure 3 The left figure in it is the appearance shape of the existing metal aluminum pigment for spray-free use after being broken, Figure 3 and the right figure in it is the effect of the metal aluminum pigment for spray-free use of the present invention broken under the same conditions. Obviously, the metal aluminum pigment particles for spray-free use of the present invention after adding the embrittling agent are more finely divided and uniform, and can be more uniformly mixed with plastic particles during use.

[0052] In order to more directly reflect the change in the size and thickness of the metal aluminum pigment for spray-free use before and after being broken, now 10 samples are taken from 5 batches of products in the production sample randomly, and their particle sizes are measured. The instrument used for measurement is the BETTER BT-2900 dry image particle size and shape analyzer. The measurement results show that the average particle size of the existing metal aluminum pigment for spray-free use after being broken is 829.2 um, while the average particle size of the metal aluminum pigment for spray-free use of the present invention after being broken is 114.1 um.

[0053]

[0054] The present invention can make the pigment after granulation and drying easier to break by adding an embrittling agent, which can greatly reduce the breaking time of the metal aluminum pigment for spray-free use in the pulverizer, effectively preserve the shape of the metal aluminum flakes in the metal aluminum pigment for spray-free use, reduce the color difference of the injection-molded products, improve the aesthetics of the injection-molded products, and also reduce the production cost. At the same time, it can also make the appearance size of the broken pigment uniform and more uniform when mixed with plastic particles.

[0055] The present invention has been specifically described above in combination with the embodiments, but those skilled in the art in this technical field can make various changes or variations to these embodiments, and these changes and variations should fall within the protection scope of the present invention.

Claims

1. A metal aluminum pigment for spray-free use with embrittlement performance, which is processed by a kneader from raw materials with the following weight percentage contents: 60%-75% of metal aluminum pigment, 20%-35% of epoxy resin, 2%-6% of diffusion powder, and 3%-5% of embrittling agent; Among them, The metal aluminum pigment is a flaky aluminum pigment obtained by ball-milling aluminum powder; the weight ratio of metal aluminum in the metal aluminum pigment is 70%-80%, petroleum solvent and additives account for 20%-30%, and the particle size of the metal aluminum pigment is between 5um and 50um; The embrittling agent is at least one of NaF, Al2O3, mica or glass powder; The metal aluminum pigment for spray-free use is prepared by the following method, and the steps are as follows: Step 1: Weigh various raw materials for preparing the metal aluminum pigment for spray-free use according to the ratio, pre-add the embrittling agent and the diffusion powder to the metal aluminum pigment, and add them to a kneader and stir for 0.5 h to obtain a mixture; Step 2: Then add the epoxy resin to the mixture, heat it to 110-150°C and carry out co-melting for 2-3 h to obtain a co-melted mixture; Step 3: When the co-melted mixture is cooled to 60-80°C, granulate it to obtain the metal aluminum pigment for spray-free use.

2. The aluminum metal pigment for spray-free use according to claim 1, wherein The epoxy resin is replaced by one of modified PP, modified ABS or modified polyurethane.

3. The metal aluminum pigment for spray-free use according to claim 1, characterized in that, The diffusion powder is a waxy amide.

4. The aluminum metal pigment for spray-free use according to claim 1, characterized in that, After baking the spray-free pigment particles for 7 hours, crush them, and the baking temperature is 80°C.

5. The aluminum metal pigment for spray-free use according to claim 1, characterized in that, In Step 2, after adding a petroleum solvent with a wetting effect, then carry out the heating co-melting.

6. The aluminum metal pigment for spray-free use according to claim 5, characterized in that, The dosage of the petroleum solvent is less than 1% of the total amount of the metal aluminum pigment for spray-free use.

7. The aluminum metal pigment for spray-free use according to claim 5, characterized in that, After adding the petroleum solvent, stir and mix for 5 minutes first, and then carry out the heating co-melting.

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