Laser-marking halogen-free flame-retardant reinforced polyamide material and preparation method thereof

Abstract

The invention discloses a laser-marking halogen-free flame-retardant reinforced polyamide material and a preparation method thereof, and the laser-marking halogen-free flame-retardant reinforced polyamide material comprises the following components in parts by weight: 45-65 parts of polyamide resin, 10-40 parts of glass fiber, 12-20 parts of a zinc oxide coated diethyl hypophosphite flame retardant, 0.2-0.5 part of an antioxidant and 0.3-0.5 part of a lubricant. When the material is used for laser marking, the marking color is deep, and the marking effect is good.

Description

Technical Field

[0001] This invention relates to the field of electrical connector technology, specifically to a laser-markable halogen-free flame-retardant reinforced polyamide material and its preparation method. Background Technology

[0002] Diethylphosphonate flame-retardant reinforced polyamide materials, due to their halogen-free nature, low smoke density, low density, and high CTI, have found widespread application in new energy vehicles, such as battery modules, internal structural components of battery packs, module end plates, battery brackets, electronic control systems, charging systems, and household relays and contactors. This is crucial for these electrical components, effectively preventing surface carbonization and conductivity caused by electric arcs, greatly improving product safety and reliability.

[0003] Laser marking is required on some products. Diethylphosphinate is a highly efficient flame retardant, but its chemical structure tends to decompose and vaporize after absorbing laser energy, rather than carbonizing or producing a foam layer with strong color changes like some fillers. This results in laser markings that are light in color and have low contrast, often appearing as grayish-white rather than deep black. Therefore, improving the laser marking effect of diethylphosphinate flame-retardant enhanced PA66, especially achieving a better white-to-black effect, is a problem that needs to be solved. Summary of the Invention

[0004] The purpose of this invention is to provide a halogen-free flame-retardant reinforced polyamide material that can be laser-marked and its preparation method. This material produces deep marking colors and has a good marking effect when laser-marked.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a laser-markable halogen-free flame-retardant reinforced polyamide material, comprising, by weight, 45-65 parts polyamide resin, 10-40 parts glass fiber, 12-20 parts zinc oxide-coated diethyl hypophosphite flame retardant, 0.2-0.5 parts antioxidant and 0.3-0.5 parts lubricant.

[0006] Preferably, the diethyl hypophosphite is one or more of aluminum hypophosphite, diethyl aluminum hypophosphite, dipropyl aluminum hypophosphite, phenyl aluminum hypophosphite, methyl phenyl aluminum hypophosphite, ethyl phenyl aluminum hypophosphite, zinc hypophosphite, phenyl zinc hypophosphite, gadolinium hypophosphite, calcium hypophosphite, and magnesium hypophosphite.

[0007] Preferably, the polyamide resin is one or more of nylon 6, nylon 46, nylon 56, nylon 66, nylon 11, nylon 12, nylon 610, nylon 612 and nylon 1010.

[0008] Preferably, the antioxidant is one or more of phosphites, hindered phenols, and thioesters.

[0009] Preferably, the lubricant is one or a mixture of more than one of silicone, polyethylene wax, ethylene acrylic acid copolymer, calcium stearate, montan wax, and rice bran wax.

[0010] This invention also provides a method for preparing a laser-markable halogen-free flame-retardant reinforced polyamide material, which includes the following steps:

[0011] (1) Wet and disperse diethyl hypophosphite in water to prepare a well-dispersed diethyl hypophosphite suspension;

[0012] (2) Dissolve the selected soluble zinc salt in deionized water to prepare a clear zinc salt solution;

[0013] (3) Add the diethyl hypophosphite suspension to the reactor, start stirring and heat to 60℃-80℃. Add the zinc salt solution to the reactor and mix with the diethyl hypophosphite suspension. Slowly add the precipitant dilute NaOH solution and control the pH value to pH=8-10. Zinc ions (Zn) 2+ It will hydrolyze under alkaline conditions to produce zinc hydroxide (Zn(OH)2) or directly produce basic salts of zinc. These insoluble substances will preferentially nucleate and deposit heterogeneously on the surface of diethyl hypophosphite particles.

[0014] (4) After the addition of materials is completed, continue to stir and react at a constant temperature for 1-2 hours (maturation process) to allow the deposition reaction to completely form the coating layer. After the reaction is completed, cool naturally to room temperature to obtain zinc oxide coated diethyl phosphite flame retardant.

[0015] (5) The nylon resin is dried, and then zinc oxide-coated diethyl hypophosphite flame retardant, antioxidant, glass fiber and nylon resin are uniformly mixed according to the required weight parts and added to a twin-screw extruder for melt blending, extrusion granulation to prepare a halogen-free flame-retardant reinforced polyamide material that can be laser-marked. Due to its chemical structure, diethyl hypophosphite tends to decompose and vaporize after absorbing laser energy, and cannot form a carbonized layer with strong color changes. This results in a light white-to-black marking color and low contrast. However, after diethyl hypophosphite is coated with zinc oxide, the coating layer reflects most of the laser energy, causing carbonization of the polyamide, making the black mark darker during laser marking and significantly improving the white-to-black effect.

[0016] Preferably, after step (4) is completed, the slurry after reaction is filtered and washed with a large amount of deionized water and / or ethanol to remove residual ions, and a filter cake is obtained. The filter cake is then fully dried in a vacuum drying oven at 80-100°C.

[0017] The beneficial effects of this invention are: the laser-markable halogen-free flame-retardant reinforced polyamide material of this invention produces a deep, dark black mark when laser-marked, resulting in a good marking effect. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0019] Comparative Example 1

[0020] Mix 18% aluminum diethyl phosphite flame retardant, 0.15% antioxidant 1098, 0.15% antioxidant 9228, 0.5% rice bran wax R05, 48.2% PA6, and 3% zinc sulfide evenly according to the required weight parts, and side feed 30% glass fiber. Add the mixture to a twin-screw extruder for melt blending, extrusion granulation, and granulation.

[0021] Comparative Example 2

[0022] Mix 18% aluminum diethyl phosphite flame retardant, 0.15% antioxidant 1098, 0.15% antioxidant 9228, 0.5% rice bran wax R05, 48% PA6, 3% zinc sulfide, and 0.2% Merck laser marking agent 8850 evenly according to the required weight proportions, add 30% glass fiber side feed, and add to a twin-screw extruder for melt blending, extrusion granulation.

[0023] Comparative Example 3

[0024] Mix 18% aluminum diethyl phosphite flame retardant, 0.15% antioxidant 1098, 0.15% antioxidant 9228, 0.5% rice bran wax R05, 47.7% PA6, 3% zinc sulfide, and 0.5% Merck laser marking agent 8850 evenly according to the required weight proportions, and add 30% glass fiber side-feed. Add the mixture to a twin-screw extruder for melt blending, extrusion granulation, and granulation.

[0025] Comparative Example 4

[0026] Mix 14% aluminum diethyl phosphite flame retardant, 0.15% antioxidant 1098, 0.15% antioxidant 9228, 0.5% rice bran wax R05, 52% PA6, 3% zinc sulfide, and 0.2% Merck laser marking agent 8850 evenly according to the required weight proportions, and add 30% glass fiber side-feed. Add the mixture to a twin-screw extruder for melt blending, extrusion granulation, and granulation.

[0027] Comparative Example 5

[0028] Mix 14% aluminum diethyl phosphite flame retardant, 0.15% antioxidant 1098, 0.15% antioxidant 9228, 0.5% rice bran wax R05, 53% PA6, 2% zinc oxide, and 0.2% Merck laser marking agent 8850 evenly according to the required weight parts, and side feed 30% glass fiber. Add the mixture to a twin-screw extruder for melt blending, extrusion granulation, and granulation.

[0029] Example 1

[0030] A method for preparing a laser-markable halogen-free flame-retardant reinforced polyamide material is as follows:

[0031] (1) Preparation of zinc oxide-coated diethylaluminum hypophosphite flame retardant: 1. Wet and disperse diethylaluminum hypophosphite in water at a mass ratio of 1:20 to prepare a well-dispersed diethylaluminum hypophosphite suspension; 2. Dissolve the selected soluble zinc salt in deionized water at a mass ratio of 1:20 to prepare a clear zinc solution; 3. Add the diethylaluminum hypophosphite suspension to a reaction vessel, start stirring and heat to a specific temperature of 60-80℃, add the zinc salt solution to the reaction vessel and mix with the diethylaluminum hypophosphite suspension at a mass ratio of 1:9, slowly add the precipitant dilute NaOH solution, and strictly control the pH value to pH=8-10, zinc ions (Zn) 2+ Under alkaline conditions, it will hydrolyze to produce zinc hydroxide (Zn(OH)2). These insoluble substances will preferentially nucleate and deposit on the surface of diethylaluminum hypophosphite particles. 4. After the addition is complete, continue stirring at a constant temperature for 2 hours to ensure complete deposition and a denser coating. After the reaction is complete, allow it to cool naturally to room temperature. Filter the slurry after the reaction and wash it with plenty of deionized water to remove residual ions (such as Na+). + NO3 - The filter cake was thoroughly dried and dehydrated in a vacuum drying oven at 130°C to convert it into a ZnO coating layer, thus obtaining zinc oxide-coated aluminum diethyl phosphite.

[0032] (2) Preparation of laser-markable light-colored halogen-free flame-retardant reinforced polyamide material: 20 wt% zinc oxide-coated diethyl phosphite, 0.15% antioxidant 1098, 0.15% antioxidant 9228, 0.5% rice bran wax R05, 0.2% Merck laser marking agent 8850, and 49% PA6 resin were uniformly mixed in a high-speed mixer, and 30 wt% glass fiber was side-fed. The mixture was then added to a twin-screw extruder for melt blending, extrusion granulation, and laser-markable light-colored halogen-free flame-retardant reinforced PA6 material.

[0033] Example 2

[0034] A method for preparing a laser-markable halogen-free flame-retardant reinforced polyamide material is as follows:

[0035] (1) Preparation of zinc oxide-coated diethylaluminum hypophosphite flame retardant: 1. Wet and disperse diethylaluminum hypophosphite in water at a mass ratio of 1:50 to prepare a well-dispersed diethylaluminum hypophosphite suspension; 2. Dissolve the selected soluble zinc salt in deionized water at a mass ratio of 1:50 to prepare a clear zinc solution; 3. Add the diethylaluminum hypophosphite suspension to a reaction vessel, start stirring and heat to a specific temperature of 60-80℃, add the zinc salt solution to the reaction vessel and mix with the diethylaluminum hypophosphite suspension at a mass ratio of 1:9, slowly add the precipitant dilute NaOH solution, and strictly control the pH value to pH=8-10, zinc ions (Zn) 2+ Under alkaline conditions, it will hydrolyze to produce zinc hydroxide (Zn(OH)2). These insoluble substances will preferentially nucleate and deposit on the surface of diethylaluminum hypophosphite particles. 4. After the addition is complete, continue stirring at a constant temperature for 2 hours to ensure complete deposition and a denser coating. After the reaction is complete, allow it to cool naturally to room temperature. Filter the slurry after the reaction and wash it with plenty of deionized water to remove residual ions (such as Na+). + NO3 - The filter cake was thoroughly dried and dehydrated in a vacuum drying oven at 130°C to convert it into a ZnO coating layer, thus obtaining zinc oxide-coated aluminum diethyl phosphite.

[0036] (2) Preparation of laser-markable light-colored halogen-free flame-retardant reinforced polyamide material: 20 wt% zinc oxide-coated diethyl phosphite, 0.15% antioxidant 1098, 0.15% antioxidant 9228, 0.5% rice bran wax R05, 0.2% Merck laser marking agent 8850, and 49% PA6 resin were uniformly mixed in a high-speed mixer, and 30 wt% glass fiber was side-fed. The mixture was then added to a twin-screw extruder for melt blending, extrusion granulation, and laser-markable light-colored halogen-free flame-retardant reinforced PA6 material.

[0037] Example 3

[0038] A method for preparing a laser-markable halogen-free flame-retardant reinforced polyamide material is as follows:

[0039] (1) The zinc oxide-coated diethylaluminum hypophosphite flame retardant was prepared as in Example 1;

[0040] (2) Preparation of laser-markable light-colored halogen-free flame-retardant reinforced polyamide material: 20 wt% zinc oxide coated diethyl phosphite, 0.15% antioxidant 1098, 0.15% antioxidant 9228, 0.5% rice bran wax R05, and 49.2% PA6 resin were uniformly mixed in a high-speed mixer, and 30 wt% glass fiber was side-fed. The mixture was then added to a twin-screw extruder for melt blending, extrusion granulation, and laser marking of light-colored halogen-free flame-retardant reinforced PA6 material.

[0041] Example 4

[0042] A method for preparing a laser-markable halogen-free flame-retardant reinforced polyamide material is as follows:

[0043] (1) The zinc oxide-coated diethylaluminum hypophosphite flame retardant was prepared as in Example 2;

[0044] (2) Preparation of laser-markable light-colored halogen-free flame-retardant reinforced polyamide material: 20 wt% zinc oxide coated diethyl phosphite, 0.15% antioxidant 1098, 0.15% antioxidant 9228, 0.5% rice bran wax R05, and 49.2% PA6 resin were uniformly mixed in a high-speed mixer, and 30 wt% glass fiber was side-fed. The mixture was then added to a twin-screw extruder for melt blending, extrusion granulation, and laser marking of light-colored halogen-free flame-retardant reinforced PA6 material.

[0045] Example 5

[0046] A method for preparing a laser-markable halogen-free flame-retardant reinforced polyamide material is as follows:

[0047] (1) Preparation of zinc oxide-coated diethylaluminum hypophosphite flame retardant: 1. Wet and disperse diethylaluminum hypophosphite in water at a mass ratio of 1:50 to prepare a well-dispersed diethylaluminum hypophosphite suspension; 2. Dissolve the selected soluble zinc salt in deionized water at a mass ratio of 1:50 to prepare a clear zinc solution; 3. Add the diethylaluminum hypophosphite suspension to a reaction vessel, start stirring and heat to a specific temperature of 60-80℃, add the zinc salt solution to the reaction vessel and mix with the diethylaluminum hypophosphite suspension at a mass ratio of 2:8, slowly add the precipitant dilute NaOH solution, and strictly control the pH value to pH=8-10, zinc ions (Zn) 2+ Under alkaline conditions, it will hydrolyze to produce zinc hydroxide (Zn(OH)2). These insoluble substances will preferentially nucleate and deposit on the surface of diethylaluminum hypophosphite particles. 4. After the addition is complete, continue stirring at a constant temperature for 2 hours to ensure complete deposition and a denser coating. After the reaction is complete, allow it to cool naturally to room temperature. Filter the slurry after the reaction and wash it with plenty of deionized water to remove residual ions (such as Na+). + NO3 - The filter cake was thoroughly dried and dehydrated in a vacuum drying oven at 130°C to convert it into a ZnO coating layer, thus obtaining zinc oxide-coated aluminum diethyl phosphite.

[0048] (2) Preparation of laser-markable light-colored halogen-free flame-retardant reinforced polyamide material: 20 wt% zinc oxide-coated diethyl phosphite, 0.15% antioxidant 1098, 0.15% antioxidant 9228, 0.5% rice bran wax R05, 0.2% Merck laser marking agent 8850, and 49% PA6 resin were uniformly mixed in a high-speed mixer, and 30 wt% glass fiber was side-fed. The mixture was then added to a twin-screw extruder for melt blending, extrusion granulation, and laser-markable light-colored halogen-free flame-retardant reinforced PA6 material.

[0049] Example 6

[0050] A method for preparing a laser-markable halogen-free flame-retardant reinforced polyamide material is as follows:

[0051] (1) The zinc oxide-coated diethylaluminum hypophosphite flame retardant was prepared as in Example 1;

[0052] (2) Preparation of laser-markable light-colored halogen-free flame-retardant reinforced polyamide material: 20 wt% zinc oxide-coated diethyl phosphite, 0.15% antioxidant 1098, 0.15% antioxidant 9228, 0.5% rice bran wax R05, 0.2% Merck laser marking agent 8850, and 64% PA6 resin were uniformly mixed in a high-speed mixer, and 15 wt% glass fiber was side-fed. The mixture was then added to a twin-screw extruder for melt blending, extrusion granulation, and laser-markable light-colored halogen-free flame-retardant reinforced PA6 material.

[0053] Example 7

[0054] A halogen-free flame-retardant reinforced polyamide material that can be laser-marked is prepared as follows:

[0055] (1) The zinc oxide-coated diethylaluminum hypophosphite flame retardant was prepared as in Example 1;

[0056] (2) Preparation of laser-markable light-colored halogen-free flame-retardant reinforced polyamide material: 15.5 wt% zinc oxide-coated diethyl hypophosphite, 0.15% antioxidant 1098, 0.15% antioxidant 9228, 0.5% rice bran wax R05, 0.2% Merck laser marking agent 8850 and 53.5% PA6 resin were uniformly mixed in a high-speed mixer, 30 wt% glass fiber was side-fed, and the mixture was added to a twin-screw extruder for melt blending, extrusion and granulation to obtain laser-markable light-colored halogen-free flame-retardant reinforced PA6 material.

[0057] Example 8

[0058] A halogen-free flame-retardant reinforced polyamide material that can be laser-marked is prepared as follows:

[0059] (1) The zinc oxide-coated diethylaluminum hypophosphite flame retardant was prepared as in Example 1;

[0060] (2) Preparation of laser-markable light-colored halogen-free flame-retardant reinforced polyamide material: 20 wt% zinc oxide-coated diethyl phosphite, 0.15% antioxidant 1098, 0.15% antioxidant 9228, 0.5% rice bran wax R05, 0.5% Merck laser marking agent 8850, and 48.7% PA6 resin were uniformly mixed in a high-speed mixer, and 30 wt% glass fiber was side-fed. The mixture was then added to a twin-screw extruder for melt blending, extrusion granulation, and laser-markable light-colored halogen-free flame-retardant reinforced PA6 material.

[0061] The tensile strength of the materials prepared in the above comparative examples and embodiments was tested using a universal tensile tester in accordance with GB / T 1040.1-2018 standard; the notched impact strength was measured using a simply supported beam impact testing machine in accordance with GB / T 1043.1-2018 standard; the vertical flame retardancy was measured using a vertical-horizontal flame measuring instrument in accordance with GB / T 2408-2021 standard; and the laser marking contrast ΔE was measured using a colorimeter in accordance with ISO9001-2015 standard. The measurement data are shown in the table below:

[0062]

[0063]

[0064] As can be seen from the table above, the laser marking performance of the light-colored halogen-free flame-retardant reinforced PA6 material prepared in the embodiments of the present invention is better than that of the comparative example, and the marking color is darker when laser marking.

[0065] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A laser-markable halogen-free flame-retardant reinforced polyamide material, characterized in that, By weight, it contains 45-65 parts polyamide resin, 10-40 parts glass fiber, 12-20 parts zinc oxide-coated diethyl hypophosphite flame retardant, 0.2-0.5 parts antioxidant and 0.3-0.5 parts lubricant.

2. The laser-markable halogen-free flame-retardant reinforced polyamide material according to claim 1, characterized in that: The diethyl hypophosphite is one or more of the following: aluminum hypophosphite, diethyl aluminum hypophosphite, dipropyl aluminum hypophosphite, phenyl aluminum hypophosphite, methyl phenyl aluminum hypophosphite, ethyl phenyl aluminum hypophosphite, zinc hypophosphite, phenyl zinc hypophosphite, gadolinium hypophosphite, calcium hypophosphite, and magnesium hypophosphite.

3. The laser-markable halogen-free flame-retardant reinforced polyamide material according to claim 1, characterized in that: The polyamide resin is one or more of nylon 6, nylon 46, nylon 56, nylon 66, nylon 11, nylon 12, nylon 610, nylon 612 and nylon 1010.

4. The laser-markable halogen-free flame-retardant reinforced polyamide material according to claim 1, characterized in that: The antioxidant is one or more of the following: phosphites, hindered phenols, and thioesters.

5. The laser-markable halogen-free flame-retardant reinforced polyamide material according to claim 1, characterized in that: The lubricant is one or a mixture of more than one of the following: silicone, polyethylene wax, ethylene-acrylic acid copolymer, calcium stearate, montan wax, and rice bran wax.

6. A method for preparing a laser-markable halogen-free flame-retardant reinforced polyamide material according to any one of claims 1-5, characterized in that, Includes the following steps: (1) Wet and disperse diethyl hypophosphite in water to prepare a well-dispersed diethyl hypophosphite suspension; (2) Dissolve the selected soluble zinc salt in deionized water to prepare a clear zinc salt solution; (3) Add the diethyl hypophosphite suspension to the reactor, turn on the stirring and heat to 60℃-80℃, add the zinc salt solution to the reactor and mix with the diethyl hypophosphite suspension, slowly add the precipitant dilute NaOH solution, and control the pH value to pH=8-10. Zinc ions hydrolyze under alkaline conditions to generate zinc hydroxide or directly generate basic salts of zinc. These insoluble substances will preferentially nucleate and deposit on the surface of diethyl hypophosphite particles. (4) After the addition of materials is completed, continue to stir the reaction at a constant temperature for 1-2 hours to allow the deposition reaction to form a coating layer. After the reaction is completed, cool naturally to room temperature to obtain zinc oxide coated diethyl phosphite flame retardant. (5) The nylon resin is dried, and then zinc oxide-coated diethyl hypophosphite flame retardant, antioxidant, glass fiber and nylon resin are uniformly mixed according to the required weight parts and added to a twin-screw extruder for melt blending, extrusion granulation, and preparation of halogen-free flame-retardant reinforced polyamide material that can be laser marked.

7. The method for preparing laser-markable halogen-free flame-retardant reinforced polyamide material according to claim 6, characterized in that, After step (4) is completed, the slurry after reaction is filtered and washed with a large amount of deionized water and / or ethanol to remove residual ions, and a filter cake is obtained. The filter cake is then dried thoroughly in a vacuum drying oven at 80-100℃.

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