A polyamide material resistant to oil pollution and its preparation method and application

Abstract

The present invention discloses a polyamide material resistant to oil pollution, which is prepared by the following components in parts by weight: 100 parts of polyamide powder, 0.2-1.5 parts of interference material, 0.01-0.5 parts of oil-resistant additive powder, and 0-3 parts of other additives. The oil-resistant additive is a lubricating base oil, which contains at least one base oil, whose chemical structure is an alkane with an unsaturation of <5%, a viscosity lower than 1000cst (25°C), and a boiling point or short-term thermal decomposition temperature higher than 350°C, and the base oil content in the overall oil-resistant additive is not less than 50%. The present invention uses a special oil-resistant additive to treat the surface of nylon powder, so that after coating the metal surface, the effect of pollutants is reduced or even eliminated to cause the phenomenon of "fish eyes". And after such treatment, other processes and performance of the powder are not affected.

Description

Technical Field

[0001] The invention relates to the technical field of polymer modification, in particular to an oil-pollution-resistant polyamide material and a preparation method and application thereof. Background Art

[0002] The dishwashing basket is a wire basket used to carry dishes and other tableware in the dishwasher. It is mainly based on a frame welded from carbon steel wires, and is coated with a layer of tough, heat-resistant and waterproof resin material on its surface. The rubber coating on the surface of the bowl basket is now mainly made of long-chain nylon or polypropylene, which is usually achieved by dipping.

[0003] In order to make the surface of the bowl and basket have a glossy appearance, pearlescent powder or metal powder and other raw materials are usually added to the encapsulation formula to make the surface have a luster close to that of metal. As for the addition method of pearlescent powder and metal powder, if they are added to the resin during the modification process, they will be sheared and destroyed by the equipment during the modification process. After dipping, the effect pigments are coated in the resin and arranged in a disorderly manner, so that the effect pigments have a weaker effect in improving the metallic luster. Therefore, the current mainstream solution is to make powder after modifying nylon, and then add effect pigments to the powder to finally obtain a better gloss appearance.

[0004] However, this method of addition has a greater risk when used. If the powder falls into polypropylene, polyethylene or grease dropped from the dipping equipment, various powders decomposed by oxidation, or even oil and gas in the fluidized bed gas path, or pollution during the powder production process, it will cause the coating surface to appear a phenomenon called "fish eyes". The microscopic phenomenon is that the effect raw material is pushed away from the center of the "fish eye" to the periphery, so that the surface of the "fish eye" part has no pearlescent luster at all, and the gloss and color are different from the surrounding area, forming a black spot defect with a diameter of about 1-2mm on the surface of the bowl basket; even worse, there will be a volcanic structure with a concave "fish eye" and a protruding periphery, forming a large defect of 3-5mm in diameter. Since "fish eyes" can appear with very little external pollution, this phenomenon is very difficult to prevent by improving the production environment.

[0005] The reason for the "fish eye" is based on a phenomenon called the Bénard cell effect, which is that when two liquids with different surface tensions come into contact, the liquid will flow from the phase with low surface tension to the phase with high surface tension. In nylon powder, the nylon resin is the phase with high surface tension, while the pollutant is the phase with low surface tension. When the pollutant flows toward the nylon resin, the effect pigment on its surface will migrate accordingly.

[0006] In thermosetting powder coatings, the Bénard vortex effect also causes "fish eyes" or orange peel patterns, and leveling agents such as polyacrylates are usually used to eliminate this effect. However, since the properties of nylon resins are different from those of epoxy resins and unsaturated polyesters, commonly used coating leveling agents have no significant effect on nylon powder coatings. In addition, since the temperature of nylon powder dipping is much higher than the operating temperature of thermosetting resins, leveling agents are prone to decomposition, causing other potential risks.

[0007] The patent published by Arkema (CN102666757A) discloses a technology for eliminating "fish eyes" using polypropylene glycol, which can reduce the frequency of "fish eyes" generated by the powder itself, but the solution has a weak effect on resisting external pollution. Summary of the invention

[0008] The present invention provides an oil-pollution-resistant polyamide material and a preparation method and application thereof to solve the problems raised in the above-mentioned background technology. Without introducing other problems, the pollution resistance of powder coatings is improved and the possibility of "fish eyes" generated during the use of powder is reduced.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] A polyamide material resistant to oil pollution is prepared from the following components in parts by weight: 100 parts of polyamide powder, 0.2-1.5 parts of interference material, 0.01-0.5 parts of oil-resistant additives, and 0-3 parts of other additives.

[0011] In a further embodiment, the polyamide powder is a blend or copolymer of one or more of PA11, PA12, PA610, PA612, PA510, PA513, PA515, PA1012, PA1010, PA6, PA66, PA46, PA56 and nylon elastomer.

[0012] In a further embodiment, the polyamide powder has a melt index of less than 60 g / 10 min and a particle size of 10-300 μm.

[0013] In a further embodiment, the interference material is at least one of mica powder, glass flakes, or ultrafine metal powder with a coating or a deposition layer.

[0014] Specifically, a layer of metal oxide with controllable thickness is plated on the surface of mica, glass and other sheet materials by chemical vapor deposition. Commonly used metal oxides include titanium dioxide, iron oxide, etc. Or ultra-fine metal powder is produced by ball milling and chemical surface modification.

[0015] In a further embodiment, the oil-resistant additive is a lubricating base oil.

[0016] Preferably, the lubricating base oil is a mixture of one or more of a mineral base oil and a synthetic base oil.

[0017] Preferably, the lubricating base oil contains at least one base oil, whose chemical structure is an alkane with an unsaturation degree of <5%, a viscosity lower than 1000 cst (25°C), and a boiling point or short-time thermal decomposition temperature higher than 350°C, and the content of the base oil in the overall oil-resistant additive is not less than 50%.

[0018] Lubricating base oils can be divided into five categories according to the American Petroleum Institute (API). Among them, in categories II, III, and IV, the chemical structure is alkanes with an unsaturation degree of <5%, a viscosity lower than 1000 cst (25°C), and a boiling point or short-term thermal decomposition temperature higher than 350°C, which can meet the scope of this application.

[0019] The other auxiliary agents include toner, antioxidant and anticaking agent.

[0020] A second object of the present invention is to provide a method for preparing the above-mentioned polyamide material, which comprises the following steps:

[0021] The polyamide powder, interference material, oil-resistant additive and other additives are weighed according to weight and put into a high-speed mixer, and stirred continuously at 600-1000 rpm for 3-10 minutes to obtain a polyamide material.

[0022] The third invention objective of the present invention is to provide an application of the above-mentioned polyamide material, wherein the polyamide material is used as a coating material on a metal surface, such as a rubber coating on a bowl or basket surface.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The purpose of adding interference in this application is to improve the texture and gloss of the surface of the bowl basket. Usually, after adding interference or reflective materials, the surface of the bowl basket has a better gloss and a texture closer to the metal effect, so it has a stronger aesthetic feeling and meets the appearance positioning of high-end dishwashers. However, in the dipping process, due to the presence of oily pollutants and the Bénard vortex effect on the surface of the nylon coating, the effect pigment will be pushed to the outside, forming spots, which has become a problem in the industry.

[0025] The present invention uses a special oil-resistant additive to treat the surface of nylon powder, so that after coating the metal surface, the "fish eye" phenomenon caused by the influence of pollutants is reduced or even eliminated. After such treatment, other processes and use performances of the powder are not affected. DETAILED DESCRIPTION

[0026] For ease of understanding of the present invention, the present invention will be described more fully below in conjunction with specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thoroughly understood.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0028] The specific information of the raw materials used in the following examples and comparative examples is as follows:

[0029] Polyamide powder, commercially available polyamide particles are selected and cooled to below -100°C in liquid nitrogen, and then ground into powder by mechanical crushing method, and then sieved with a suitable sieve to obtain powder with a particle size of 50-250μm and a melt index of 50g / 10min. The polyamide particles are PA1012 from Shandong Dongchen Ruisen.

[0030] Oil resistant additive 1: Class III oil 500N, viscosity 90cst, boiling point>350℃, Formosa Plastics;

[0031] Oil resistant additive 2: α-olefin oil (PAO40), viscosity 400cst, boiling point>350℃, Chemtura;

[0032] Oil resistant additive 3: natural gas-derived synthetic oil (GTL), G100, viscosity 4cst, boiling point <260°C, Shell;

[0033] Oil resistant additive 4: α-olefin oil (PAO100), viscosity 1200cst, boiling point>350℃, Chemtura;

[0034] Interference material 1: Mica powder with titanium dioxide layer deposited on the surface, Iriodin 6111, Merck, USA;

[0035] Interference material 2: Aluminum powder, STANDART PCR 501, Eckart, Germany.

[0036] It can be understood that the above raw materials and reagents are only examples of some specific embodiments of the present invention, which makes the technical solution of the present invention clearer, and does not mean that the present invention can only adopt the above reagents. The specific scope shall be subject to the scope in the claims.

[0037] Any range described in the present invention includes the end value and any numerical value between the end values ​​and any sub-range formed by the end value or any numerical value between the end values.

[0038] The examples and comparative examples were prepared as follows: the obtained polyamide powder coating product was put into a fluidized barrel, and after compressed air was introduced, the fluidity of the powder coating was observed. A rust- and oil-free steel sheet (100mm*70mm*2mm) was heated to 300-400°C, immersed in the powder coating for 3-10 seconds, and after being taken out, the "fish eye" condition of the appearance after dipping was observed.

[0039] In order to reflect the pollution resistance of this scheme, the following pollutants were designed in the experiment:

[0040] Simulated pollutant 1: PA1012 / polyethylene wax = 95:5 blended and extruded, then ground into powder with the same specifications as nylon powder;

[0041] Simulated pollutant 2: compressed air, containing 50-500ppm lubricating oil and a small amount of water vapor, air compressor lubricating oil brand L-DAA100, Great Wall.

[0042] The addition amount of simulated pollutant 1 is 0.1%, which is added after the powder is put into the fluidized bed and stirred and mixed evenly under the action of airflow; the pressure of simulated pollutant 2 is 0.1 bar, and the dry gas is switched to the gas path of simulated pollutant 2 with oil and water when necessary.

[0043] Examples 1-4 and Comparative Examples 1-2 and Comparative Examples 4-5 were prepared according to the following method:

[0044] According to the proportions in Table 1 below, corresponding weight portions of polyamide powder, oil-resistant additives, interference materials and other additives are weighed and put into a high-speed mixer, and stirred continuously at 800 rpm for 5 minutes to obtain the final polyamide powder product.

[0045] The difference between the preparation process of Comparative Example 3 and the above preparation process is that the temperature of the high speed mixer is kept at room temperature from beginning to end.

[0046] The unit of the amount of each component in the following Table 1 is: part, wherein the other additives in each embodiment are composed of 0.5 parts of antioxidant 1010, 0.3 parts of amide wax and 0.2 parts of nano alumina.

[0047] Table 1

[0048] Components Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Polyamide powder 100 100 100 100 100 100 100 100 Interference material 1 0.3 0.8 0.5 0.5 0.3 0.3 0.8 0.5 Interference material 2 / 0.1 0.3 0.3 / / 0.1 0.3 Oil resistant additive 1 0.01 / / / / / / / Oil resistant additive 2 / 0.5 0.3 / / / / / Oil resistant additive 3 / / / 0.2 / 0.01 / 0.5 Oil resistant additive 4 / / 0.2 0.3 / / 0.5 / Other additives 1 1 1 1 1 1 1 1

[0049] The polyamide material prepared in the embodiment and the comparative example is then coated onto the surface of the steel sheet to form a coating layer material in the following manner:

[0050] The obtained polyamide material product was put into a fluidized bed, and after compressed air was introduced, the fluidity of the polyamide coating was observed, as shown in Table 2.

[0051] Then, the rust- and oil-removed steel sheet (100mm*70mm*2mm) was heated to 300-400℃, immersed in the polyamide coating for 3-10 seconds, and then taken out, and the number of "fish eyes" on both sides of the lower 80mm*70mm of the steel sheet was counted, and the number was visible to the naked eye. The test results are shown in Table 2.

[0052] Table 2

[0053]

[0054] Combined with Table 1-2 for analysis:

[0055] Comparison of Comparative Example 1 and Example 1 shows that the formula itself has no "fish eye" problem, but more "fish eyes" will be formed under the action of pollutants. In products without other additives, more "fish eyes" will be formed under the action of pollutants, among which the pollution effect of pollutant 1 is more significant. After adding oil-resistant additive 1, the number of "fish eyes" is significantly improved compared with that without adding.

[0056] Comparison of Comparative Example 2 and Example 1 shows that the oil-resistant additive 3 has a low boiling point and can cause "fish eyes" by itself, and more fish eyes will be produced under the action of pollutants. However, the oil-resistant additive 1 does not produce "fish eyes" by itself and can effectively reduce the number of fish eyes in the presence of pollutants.

[0057] Comparison of Comparative Example 3 and Example 2 shows that due to the high viscosity of the oil-resistant additive 4, it cannot be fully dispersed during the high mixing process, so even if it has a good effect of preventing "fish eyes", it will have a certain impact on the fluidity of the powder. However, the low-viscosity oil-resistant additive 2 does not have a dispersion problem and has good powder fluidity.

[0058] By comparing Comparative Example 3 with Example 3, it can be seen that after the oil-resistant additive 4 is diluted with the oil-resistant additive 2, the overall viscosity decreases and the mixing treatment in the high-speed mixer can be well dispersed, thereby obtaining both good fluidity and the effect of preventing "fish eyes".

[0059] By comparing Comparative Example 4 with Example 4, it can be seen that the oil-resistant additive 4 diluted with the oil-resistant additive 3 can be well dispersed in the powder and has a good effect of preventing "fish eyes". In contrast, using only the oil-resistant additive 3 not only causes "fish eyes" itself, but also obtains more fish eyes in the case of pollution.

[0060] Although this specification is described according to implementation modes, not every implementation mode includes only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

[0061] Therefore, the above description is only a preferred embodiment of the present application and is not intended to limit the scope of implementation of the present application; that is, all equivalent changes made according to the scope of the claims of the present application are within the protection scope of the claims of the present application.

Claims

1. A polyamide material resistant to oil pollution, characterized in that: It is prepared from the following components in parts by weight: 100 parts of polyamide powder, Interference material 0.2-1.5 parts, Oil resistant additive 0.01-0.5 parts, Other additives 0-3 parts; The interference material is at least one of mica powder, glass flakes, or ultrafine metal powder having a coating or deposition layer of metal oxide; The oil-resistant additive is a lubricating base oil, which contains at least one base oil, whose chemical structure is an alkane with an unsaturation degree of <5%, a viscosity of less than 1000cst at 25°C, a boiling point or a short-time thermal decomposition temperature of greater than 350°C, and the content of the base oil in the overall oil-resistant additive is not less than 50%.

2. The polyamide material according to claim 1, characterized in that: The polyamide powder is a blend or copolymer of one or more of PA11, PA12, PA610, PA612, PA510, PA513, PA515, PA1012, PA1010, PA6, PA66, PA46, PA56 and nylon elastomer.

3. The polyamide material according to claim 1, characterized in that: The polyamide powder has a melt index of less than 60 g / 10 min and a particle size of 10-300 microns.

4. The polyamide material according to claim 1, characterized in that: The other auxiliary agents include toner, antioxidant and anticaking agent.

5. The method for preparing a polyamide material according to any one of claims 1 to 4, characterized in that: The following steps are involved: The polyamide powder, interference material, oil-resistant additive and other additives are weighed according to weight and put into a high-speed mixer, and stirred continuously at 600-1000 rpm for 3-10 minutes to obtain a polyamide material.

6. The use of the polyamide material according to any one of claims 1 to 4, characterized in that: The polyamide material is used as a coating material on a metal surface.

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