A kind of instantaneous hydrophilic long carbon chain polyamide powder material and preparation method thereof

Abstract

The present invention discloses an instantaneous hydrophilic long carbon chain polyamide powder material and a preparation method thereof, which is prepared by weight from 100 parts of long carbon chain polyamide powder, 0.2-1.5 parts of interference material, 0.01-0.1 parts of pollution-resistant additives, 0.05-0.5 parts of hydrophilic additives, and 0-2 parts of other additives. The present invention adopts polyols as hydrophilic additives so that the nylon coating can be quickly wetted by water after being immersed in water, avoiding the occurrence of blisters, shrinkage holes and the like, but fish eyes will appear; while the pollution-resistant additive can prevent the hydrophilic additive from producing fish eyes. Therefore, the combination of hydrophilic additives and pollution-resistant additives can play a synergistic role and make up for each other's shortcomings. This hydrophilic effect is instantaneous, and in the final product, the coating surface still shows hydrophobicity.

Description

Technical Field

[0001] The invention relates to the field of polymer material modification, in particular to an instantaneous hydrophilic long carbon chain polyamide powder material and a preparation method thereof. Background Art

[0002] The dishwashing basket is a wire basket used to hold dishes and other tableware in dishwashers. It's primarily based on a frame made of welded carbon steel wire, coated with a tough, heat-resistant, and waterproof resin. The main materials used for the rubber coating on the basket are long-chain nylon or polypropylene, typically achieved through a plastic dipping process.

[0003] Bowl basket powder is usually wrapped onto a carbon steel wire frame by dipping. That is, the bowl basket powder is put into a fluidizing barrel, aerated to fluidize it, and then the bowl basket carbon steel frame is heated to 300-500℃, immersed in the bowl basket powder fluidizing barrel and vibrated for a few seconds, and then placed in a leveling furnace at 200-250℃ for leveling for 0.5-3 minutes. After coming out of the leveling furnace, it is immediately immersed in cooling water to complete the dipping of the entire bowl basket.

[0004] Because bowl and basket powder typically uses long-chain nylon and often incorporates additives to impart hydrophobicity to the resulting coating, water can't fully penetrate the coating during the immersion process, especially at certain welds, where it's even more difficult to spread. Due to the difference in thermal conductivity between air bubbles and water, the nylon coating with bubbles dissipates heat more slowly, while the coating in contact with water dissipates heat faster. This difference in solidification speed results in two defects: raised "bubbles" on the surface of the thick wire and shrinkage holes, known as "shrinkage holes," at the welds. To improve water wetting of the nylon coating, a surfactant is often added to the immersion tank. For example, household dishwashing liquid can improve "bubbles" on the thick wire, but shrinkage holes formed at the welds cannot be completely eliminated. The root cause lies in the hydrophobicity of the resin, compounded by the dead spots in the wire, which prevent the cooling water from fully wetting the welds. Summary of the Invention

[0005] In light of this, the present invention provides a transiently hydrophilic long-chain polyamide powder material and its preparation method to address the issues raised in the aforementioned background art. By using a polyhydroxy compound as a hydrophilic additive, the nylon coating is rapidly wetted by water after immersion, avoiding blisters and craters, though this can lead to the formation of fisheyes. A contamination-resistant additive prevents the formation of fisheyes in the hydrophilic additive. Therefore, the combination of the hydrophilic and contamination-resistant additives creates a synergistic effect, compensating for their respective shortcomings. This hydrophilic effect is transient, and the coating surface remains hydrophobic in the final product.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] On one hand, the present invention discloses an instantaneous hydrophilic long-chain polyamide powder material, which is prepared by weight from 100 parts of long-chain polyamide powder, 0.2-1.5 parts of interference material, 0.01-0.1 parts of pollution-resistant additive, 0.05-0.5 parts of hydrophilic additive, and 0-2 parts of other additives.

[0008] As a further embodiment of the present invention, the polyamide powder is at least one of PA11, PA12, PA610, PA612, PA510, PA513, PA515, PA1012, PA1010, PA6, PA66, PA46, PA56 and nylon elastomer.

[0009] As a further solution of the present invention: the melt index of the polyamide powder is less than 60 g / 10 min.

[0010] As a further solution of the present invention: the particle size of the polyamide powder is 10-300 microns

[0011] As a further solution of the present invention: the interference material is at least one of mica powder, glass flakes, and ultrafine metal powder.

[0012] As a further solution of the present invention: the anti-pollution additive is at least one of a mineral base oil and a synthetic base oil; the anti-pollution additive has a viscosity lower than 1000 cst, and a boiling point or a short-time thermal decomposition temperature higher than 350°C.

[0013] As a further solution of the present invention: the hydrophilic additive is a polyhydroxy compound and an aqueous solution thereof.

[0014] As a further embodiment of the present invention: the polyhydroxy compound has a solubility in water of >100 g / 100 g water, the number of hydroxyl groups in the molecule is >2, the hydroxyl content accounts for >10% of the molecular weight, the molecular weight of the compound is <400, and the viscosity is lower than 2000 cst.

[0015] As a further solution of the present invention: the other auxiliary agents are one or a combination of toner, antioxidant, and anticaking agent.

[0016] Another aspect of the present invention discloses a method for preparing the long carbon chain polyamide powder material, comprising the following steps:

[0017] The polyamide powder, interference material, anti-pollution 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 an instantaneous hydrophilic polyamide powder material.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention adds a small amount of polyol to the polyamide powder as a hydrophilic additive and uses a mineral base oil as a contamination-resistant agent to synergize with the hydrophilic additive, eliminating the problem of shrinkage cavities in the coating after immersion in water while ensuring the coating's hydrophobicity and water-boiling resistance. The hydrophilicity of the polyamide powder material provided by the present invention is transient. During immersion, the coating surface becomes hydrophilic, preventing shrinkage cavities. However, after immersion, the coating can be washed away with water, maintaining its hydrophobicity. This reduces the risk of blisters, shrinkage cavities, and fisheyes in dishwashing baskets during dipping, while also ensuring the hydrophobicity of the final product. DETAILED DESCRIPTION

[0020] To facilitate 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 provide a more thorough and comprehensive understanding of the disclosure of the present invention.

[0021] 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.

[0022] The specific information of the raw materials used in the following examples and comparative examples is as follows:

[0023] For polyamide powder, commercially available polyamide particles were cooled in liquid nitrogen to below -100°C and mechanically ground into powder. The powder was then sieved with a suitable mesh to obtain a particle size of 50-250 μm. The melt index was 50 g / 10 min. The polyamide particles used were PA1012 from Shandong Dongchen Ruisen.

[0024] PA6 / PA1012 powder: Dongchen Ruisen PA1012 and Jiangsu Hongsheng BE 3250, with a mass ratio of 70:30, are granulated by twin-screw extrusion at 250°C, then cold-ground with liquid nitrogen into powder, and the powder is screened in the range of 50-250 microns.

[0025] Interference material 1: Mica powder, Iriodin 6111, Merck, USA;

[0026] Interference material 2: flake aluminum powder, STANDART PCR 501, Eckart, Germany;

[0027] Hydrophilic additive 1: ethylene glycol 200

[0028] Hydrophilic additive 2: 10% sucrose aqueous solution

[0029] Anti-fouling additive: α-olefin oil (PAO40), viscosity 400cst, Chemtura;

[0030] Toner: Titanium Yellow, SPP-1060, Fluor;

[0031] Antioxidant: Bruggolen H10, Brüggemann;

[0032] Anticaking agent: Aerosil R972, Evonik;

[0033] All materials are commercially available common products.

[0034] It is understood that the above raw materials and reagents are only examples of some specific embodiments of the present invention, which make the technical solution of the present invention clearer, and do not mean that the present invention can only adopt the above reagents. The specific scope in the claims shall prevail. In addition, the "parts" described in the examples and comparative examples, unless otherwise specified, refer to parts by weight.

[0035] 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.

[0036] The examples and comparative examples were prepared as follows:

[0037] According to the proportions in Table 1 below, polyamide powder, hydrophilic additive, anti-fouling additive, interference material, and other additives were weighed and put into a high-speed mixer. The mixture was stirred at 800 rpm for 6 minutes to obtain the final polyamide powder product.

[0038] Table 1

[0039]

[0040] All products obtained in the examples and comparative examples were tested, and the testing method was as follows:

[0041] a. Place the finished polyamide powder coating into a fluidizing barrel, introduce compressed air, and observe the fluidity of the powder coating. Heat a derusted and degreased steel sheet (100mm*70mm*2mm) to 300-400°C, immerse it in the powder coating for 3-10 seconds, remove it, and observe the appearance of any "fish eyes" after dipping.

[0042] b. Arrange 4 iron wires of 6mm diameter and 4 iron wires of 3mm diameter in the vertical and horizontal directions respectively and weld them with a spacing of 2cm between wires to obtain a metal frame. Heat the metal frame to 300-400℃ and dip it in plastic. Then return it to 220℃ for 1 minute to allow the surface coating to completely level out. Immediately immerse it in pure water to cool it down. After picking it up, observe the number of shrinkage holes at the welding points.

[0043] c. Contact angle: Drop 10 μL of pure water on the surface of the metal frame coating, and measure the contact angle by fitting the shape of the water drop using a video light contact angle tester.

[0044] d. Place the coated metal frame in 80℃ hot water and boil for 7X 24h: observe whether there is blistering or rust on the surface of the iron plate.

[0045] The test results are shown in Table 2.

[0046] Table 2

[0047] Test items Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Number of fisheyes 0 2 0 15 32 0 0 Resistant to 80℃ hot water No rust or blistering No rust or blistering No rust or blistering No rust or blistering No rust or blistering No rust or blistering foaming Number of shrinkage cavities 1 0 0 0 0 12 6 contact angle 102 95 96 95 93 97 82

[0048] Analyze based on Table 1-2:

[0049] Comparing Comparative Examples 1 and 2 with Example 1, it can be seen that in Comparative Example 1, where no hydrophilic additive or antifouling agent was added, the product exhibited some fisheyes. However, in Comparative Example 2, the addition of the hydrophilic additive alone resulted in a significant increase in the number of fisheyes. This is because the hydrophilic additive itself can form fisheyes. However, after the antifouling additive was added, the fisheyes were completely eliminated, and the product did not cause shrinkage cavities. No shrinkage cavities were also formed after the addition of the hydrophilic additive, while an acceptable number of shrinkage cavities were produced after the addition of the antifouling additive. The addition of the antifouling additive resulted in an increase in the contact angle of the coating, while the contact angle of the product with the hydrophilic additive alone showed little change. This is because the hydrophilic additive was dissolved during immersion.

[0050] Combining Comparative Example 3 and Example 2, it can be seen that when only the anti-fouling agent is added, the contact angle of the coating surface is only slightly higher than that of the coating surface with both the hydrophilic agent and the anti-fouling agent added, but the number of shrinkage holes is greatly increased, indicating that the hydrophilic agent has a greater effect on improving shrinkage holes.

[0051] Combining Comparative Example 4 with Example 3, it can be seen that even if a more hydrophilic PA6 / PA1012 resin is selected, shrinkage cavities will still be generated when the anti-pollution additive is added alone. In addition, due to the use of PA6 with higher water absorption, the hot water resistance of the resin is reduced, and the coating and the iron plate will separate and bubble within 7 days of boiling in water.

[0052] Although this specification is described according to implementation methods, not every implementation method contains only one independent technical solution. This narrative method 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 can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0053] 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 modifications made according to the scope of the claims of the present application are within the scope of protection of the claims of the present application.

Claims

1. A transient hydrophilic long carbon chain polyamide powder material, characterized in that: The invention is prepared from 100 parts of long carbon chain polyamide powder, 0.2-1.5 parts of interference material, 0.01-0.1 parts of pollution-resistant additive, 0.05-0.5 parts of hydrophilic additive, and 0-2 parts of other additives according to weight parts; The interference material is at least one of mica powder, glass flakes, and ultrafine metal powder; The anti-pollution additive is at least one of a mineral base oil and a synthetic base oil; The hydrophilic additive is a polyhydroxy compound and its aqueous solution.

2. The long carbon chain polyamide powder material according to claim 1, characterized in that: The polyamide powder is at least one of PA11, PA12, PA610, PA612, PA510, PA513, PA515, PA1012, and PA1010.

3. The long carbon chain polyamide powder material according to claim 1, characterized in that: The particle size of the polyamide powder is 10-300 microns.

4. The long carbon chain polyamide powder material according to claim 1, characterized in that: The anti-pollution additive has a viscosity lower than 1000 cst, and a boiling point or a short-time thermal decomposition temperature higher than 350°C.

5. The long carbon chain polyamide powder material according to claim 1, characterized in that: The solubility of the polyol in water is greater than 100 g / 100 g water, the number of hydroxyl groups in the molecule is greater than 2, the hydroxyl content accounts for more than 10% of the molecular weight, the molecular weight of the compound is less than 400, and the viscosity is lower than 2000 cst.

6. The long carbon chain polyamide powder material according to claim 1, characterized in that: Other additives include color powder, antioxidant, anti-caking agent or a combination of several of them.

7. The method for preparing the long carbon chain polyamide powder material according to any one of claims 1 to 6, characterized in that: The following steps are involved: The polyamide powder, interference material, anti-pollution additive, hydrophilic 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 an instantaneous hydrophilic polyamide powder material.

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