A high temperature resistant, low moisture absorption and flame retardant PA6T composition

Abstract

The present invention provides a high-temperature-resistant, low-hygroscopicity, flame-retardant PA6T composition, comprising the following components: 100 parts by weight of PA6T material, 10-30 parts by weight of diethylaluminum hypophosphite, 0-20 parts by weight of a flame retardant synergist, 0-5 parts by weight of an antioxidant, 0-5 parts by weight of a lubricant, and 0-20 parts by weight of glass fiber. By introducing diethylaluminum hypophosphite of a specific particle size into the PA6T, even at a relatively low addition level, a product with a balanced flame retardancy and low hygroscopicity can be produced, meeting the high-temperature resistance, low hygroscopicity, and flame retardancy requirements of electronic connectors.

Description

Technical Field

[0001] The invention relates to a polyamide material for electronic connectors, in particular to a flame-retardant polyamide material for high-temperature resistant and low-moisture absorption electronic connectors. Background Art

[0002] Electronic connectors are used with PIN terminals, requiring the material to exhibit extremely high temperature resistance during PCB soldering. Recent developments in high-temperature polymers such as PA6T, PA9T, and LCP meet these requirements. Typical reflow soldering temperatures are approximately 270°C, requiring the material to withstand temperatures of at least 270°C and exhibit excellent dielectric properties and low warpage resistance, i.e., dimensional stability, after soldering.

[0003] In practice, the dimensional stability of semi-aromatic polyamide materials meets most application scenarios. However, due to the high surface temperatures during welding, blistering is common, especially in factories in southern my country. This phenomenon occurs because polyamide materials have certain hygroscopic properties. Porosity in the material, or moisture absorbed by the material during long-term storage, causes expansion and blistering at high temperatures, leading to welding failure. Porosity can be avoided by optimizing the processing technology; moisture absorbed by the material during long-term storage requires selecting materials with low hygroscopicity to optimize the process.

[0004] Generally speaking, PA6T has a shorter carbon chain than materials like PA9T and PA10T, resulting in higher heat resistance and making it an ideal material for electronic connectors. However, its higher hygroscopicity makes it less resistant to blistering under welding conditions. Therefore, for PA6T, achieving a balance between low hygroscopicity and flame retardancy while maintaining high heat resistance is a pressing technical challenge.

[0005] CN101857732A discloses a halogen-free flame-retardant resin composition, which uses a nitrogen-containing flame retardant, a metal pyrophosphate, and a fiber reinforcement as flame retardants and reinforcing agents in a nylon-based resin composition. CN106867244A discloses a flame-retardant and high-temperature resistant nylon composite material, which includes a high-temperature nylon resin, carbon fiber, a flame retardant, an auxiliary flame retardant, expanded graphite, a thermally conductive filler, an antioxidant, and a lubricant.

[0006] The present invention further improves upon the prior art by selecting PA6T with excellent high temperature resistance as the base material, thereby balancing its hygroscopicity and flame retardancy. Summary of the Invention

[0007] The object of the present invention is to provide a PA6T composition with good high temperature resistance, low hygroscopicity and good flame retardancy.

[0008] To achieve the above objectives, the present invention provides a high-temperature resistant, low-moisture-absorption, flame-retardant PA6T composition.

[0009] A high-temperature-resistant, low-moisture-absorption, flame-retardant PA6T composition comprises the following components: 100 parts by weight of PA6T material, 10-30 parts by weight of diethyl aluminum hypophosphite, 0-20 parts by weight of a flame retardant synergist, 0-5 parts by weight of an antioxidant, 0-5 parts by weight of a lubricant, and 0-20 parts by weight of glass fiber.

[0010] In a preferred embodiment, the diethyl aluminum hypophosphite is preferably 15 to 25 parts by weight, preferably 17 to 20 parts by weight.

[0011] In a preferred embodiment, the flame retardant synergist is selected from one or more of borates and metal oxides. The borate is selected from zinc borate, and the metal oxide is selected from one or more of zinc oxide and aluminum oxide.

[0012] In a preferred embodiment, the flame retardant synergist is preferably 1 to 15 parts by weight, preferably 3 to 10 parts by weight, and preferably 5 parts by weight.

[0013] In a preferred embodiment, the PA6T material is preferably one or more of PA6T / 6, PA6T / 66, and PA6T / 6I.

[0014] In a preferred embodiment, the antioxidant is selected from one or more of a hindered phenol antioxidant and a phosphite antioxidant. The hindered phenol antioxidant is selected from one or more of Antioxidant 1010, Antioxidant 1035, Antioxidant 1330, and Antioxidant 259. The phosphite antioxidant is selected from one or more of Antioxidant 168 and Antioxidant 626GE. Preferably, the weight ratio of the hindered phenol antioxidant to the phosphite antioxidant is (1-5):(1-5).

[0015] In a preferred embodiment, the antioxidant is preferably 1 to 3 parts by weight, preferably 2 parts by weight.

[0016] In a preferred embodiment, the lubricant is selected from one or more of stearate, stearamide, polyethylene wax, and erucamide.

[0017] In a preferred embodiment, the lubricant is preferably 1 to 3 parts by weight, preferably 2 parts by weight.

[0018] In a preferred embodiment, the glass fiber is preferably 5 to 15 parts by weight, preferably 10 parts by weight.

[0019] In a preferred embodiment, the in-situ enhanced flame retardant PA6T composition further comprises other additives.

[0020] In a preferred embodiment, the particle size of diethylaluminum hypophosphite satisfies the relationship (1) and the relationship (2):

[0021] 1.2≤X ≤2.3 (1)

[0022] 2.4≤Y≤3.3 (2)

[0023] in:

[0024] X is (D 90 -D 50 ) / (D 50 -D 10 ); Y is D max / D 50 ;

[0025] D 10 The particle size corresponding to the cumulative particle size distribution of diethylaluminum hypophosphite sample reaches 10%, in μm;

[0026] D 50 The particle size corresponding to the cumulative particle size distribution of diethylaluminum hypophosphite sample reaches 50%, in μm;

[0027] D 90 The particle size corresponding to 90% of the cumulative particle size distribution of diethylaluminum hypophosphite samples, in μm;

[0028] D max It is the particle size corresponding to 100% of the cumulative particle size distribution of the diethylaluminum hypophosphite sample, in μm.

[0029] In a preferred embodiment, X is preferably 1.3 to 1.7, more preferably 1.4 to 1.5, wherein the symbol "~" indicates a value including both ends.

[0030] In a preferred embodiment, Y is preferably 2.6 to 3.0, and more preferably 2.7 to 2.9, wherein the symbol "~" indicates a value including both ends.

[0031] The present invention also provides a method for preparing a high-temperature resistant, low-hygroscopic, flame-retardant PA6T composition, comprising the following steps.

[0032] (1) Add 100 parts by weight of PA6T material, 10-30 parts by weight of diethyl aluminum hypophosphite, 0-20 parts by weight of flame retardant synergist, 0-5 parts by weight of antioxidant, 0-5 parts by weight of lubricant, and 0-20 parts by weight of glass fiber into a high-speed mixer and stir to mix evenly.

[0033] (2) adding the uniformly mixed materials into the twin-screw extruder from the main feed port of the twin-screw extruder, and performing melt mixing and extrusion granulation to obtain the high-temperature resistant, low-hygroscopicity flame-retardant PA6T composition.

[0034] In a preferred embodiment, the rotation speed of the high-speed mixer in step (1) is 200 to 2000 rpm, and the mixing time is 5 to 20 minutes.

[0035] In a preferred embodiment, the extrusion granulation in step (2) further includes the steps of extrusion, strand drawing, cooling, pelletizing, and drying.

[0036] In a preferred embodiment, the processing temperature of the melt mixing in step (2) is 320-340°C.

[0037] In a preferred embodiment, the raw materials of the in-situ enhanced flame retardant PA6T composition further include other additives.

[0038] Compared with the prior art, the present invention has the following beneficial effects.

[0039] The present invention introduces diethylaluminum hypophosphite of a specific particle size into PA6T. Diethylaluminum hypophosphite has a low moisture absorption rate, making it suitable for applications requiring high low-hygroscopicity properties. Compared to other flame retardants, the alkyl portion of diethylaluminum hypophosphite has better compatibility with the long alkyl chains in PA6T. When added alone, its dispersion effect is better than other common flame retardants, such as aluminum hypophosphite, aluminum hydroxide, and magnesium hydroxide. The inventors discovered that ball milling of diethylaluminum hypophosphite does not always achieve satisfactory high-temperature resistance and low-hygroscopicity properties. In particular, when the addition amount remains the same, the particle size and particle size distribution of the diethylaluminum hypophosphite can affect the balance between high-temperature resistance and low-hygroscopicity properties of the product. The present invention introduces diethylaluminum hypophosphite of a specific particle size into PA6T, enabling products with a balanced high-temperature resistance and low-hygroscopicity properties to be achieved even at a lower addition amount, meeting the material's high-temperature resistance, low-hygroscopicity, and flame retardancy requirements for electronic connectors. DETAILED DESCRIPTION

[0040] The following further describes the embodiments of the present invention in conjunction with specific examples. People familiar with this technology can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0041] Before further describing the specific embodiments of the present invention, it should be understood that the scope of the present invention includes, but is not limited to, the following specific embodiments. Generally, the terms used in the examples of the present invention are intended to describe specific embodiments and are not intended to limit the scope of the present invention. The test methods in the following examples, where specific conditions are not specified, are generally performed under conventional conditions or according to the conditions recommended by the respective manufacturers.

[0042] When the embodiments provide numerical ranges, it should be understood that, unless otherwise specified in the present invention, both endpoints of each numerical range and any numerical value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those generally understood by those skilled in the art. In addition to the specific methods, equipment, and materials used in the embodiments, according to the understanding of the prior art by those skilled in the art and the description of the present invention, any methods, equipment, and materials of the prior art similar or equivalent to the methods, equipment, and materials described in the embodiments of the present invention may also be used to implement the present invention.

[0043] Preparation Example

[0044] Commercially available diethyl aluminum hypophosphite (D50: 22.3, D90: 35.5) was placed in a planetary ball mill for ball milling. Water was used as the dispersion medium. A combination of 20 mm, 10 mm and 2 mm zirconium beads was selected for ball milling. After ball milling, ADP was sieved through different sieves such as 500, 600, 800, 1000, and 2000 to obtain ADP with different particle sizes and particle size distributions for later use.

[0045] The greater the amount of zirconium beads with smaller diameters used, the finer the powder obtained; the longer the ball milling time, the finer the powder obtained; the finer the sieve used, the finer the powder sieved out.

[0046] Example

[0047] (1) 100 parts by weight of PA6T material and 17 parts by weight of diethyl aluminum hypophosphite as shown in Table 1 were added to a high-speed mixer and stirred at 2000 rpm for 5 minutes.

[0048] (2) The uniformly mixed materials are added into the twin-screw extruder from the main feed port of the twin-screw extruder, and the in-situ enhanced flame-retardant PA6T composition is obtained through melt mixing and extrusion granulation. The extrusion temperature is 320-340°C.

[0049] The above pellets were injection molded into standard specimens for testing.

[0050] High temperature resistance: DSC test was adopted in nitrogen atmosphere, gradient heating program, heating rate from room temperature to 150℃ was 5℃ / min, and heating rate above 150℃ was 2℃ / min.

[0051] Flame retardant performance: tested with reference to UL-94 standard, sample specification: 3.18mm.

[0052] Hygroscopicity: (1) Place the sample in an oven at 270°C for 30 minutes and visually assess whether blistering occurs. (2) Use infrared heating to melt the solder and solder the sample, and observe whether blistering occurs.

[0053] If no bubbling phenomenon was observed in both test (1) and test (2), it was marked as "○"; if bubbling phenomenon was observed in one of test (1) and test (2), it was marked as "△"; if bubbling phenomenon was observed in both test (1) and test (2), it was marked as "×".

[0054] Table 1

[0055]

[0056]

[0057] Where X is (D 90 -D 50 ) / (D 50 -D 10 ); Y is D max / D 50 .

[0058] It can be seen from Table 1 that when 1.2≤X≤2.3 and 2.4≤Y≤3.3 are met at the same time, PA6T can achieve balanced high temperature resistance and flame retardancy while maintaining high flame retardancy.

[0059] All documents mentioned in this application are incorporated herein by reference, just as if each document were incorporated herein by reference individually. It should also be understood that after reading the above teachings of the present invention, those skilled in the art may make various changes or modifications to the present invention, and that such equivalents also fall within the scope of the claims appended hereto.

Claims

1. A high temperature resistant, low moisture absorption, flame retardant PA6T composition, characterized in that: The invention comprises the following components: 100 parts by weight of PA6T material, 10 to 30 parts by weight of diethyl aluminum hypophosphite, 0 to 20 parts by weight of flame retardant synergist, 0 to 5 parts by weight of antioxidant, 0 to 5 parts by weight of lubricant, and 0 to 20 parts by weight of glass fiber; Wherein, the particle size of the diethyl aluminum hypophosphite satisfies the relationship (1) and the relationship (2): 1.2≤X≤2.3 (1) 2.4≤Y≤2.9 (2) in: X is (D 90 -D 50 ) / (D 50 -D 10 ); Y is D max / D 50 ; D 10 The particle size corresponding to the cumulative particle size distribution of diethylaluminum hypophosphite sample reaches 10%, in μm; D 50 The particle size corresponding to the cumulative particle size distribution of diethylaluminum hypophosphite sample reaches 50%, in μm; D 90 The particle size corresponding to 90% of the cumulative particle size distribution of diethylaluminum hypophosphite samples, in μm; D max It is the particle size corresponding to 100% of the cumulative particle size distribution of the diethylaluminum hypophosphite sample, in μm.

2. A high temperature resistant, low moisture absorption, flame retardant PA6T composition according to claim 1, characterized in that: The particle size of the diethyl aluminum hypophosphite satisfies the relationship: X is 1.3 to 1.

7.

3. A high temperature resistant, low moisture absorption, flame retardant PA6T composition according to claim 1, characterized in that: The particle size of the diethyl aluminum hypophosphite satisfies the relationship: X is 1.4 to 1.

5.

4. A high temperature resistant, low moisture absorption, flame retardant PA6T composition according to claim 1, characterized in that: The particle size of the diethyl aluminum hypophosphite satisfies the relationship: Y is 2.6~2.

9.

5. The high temperature resistant, low moisture absorption, flame retardant PA6T composition according to claim 1, characterized in that: The particle size of the diethyl aluminum hypophosphite satisfies the relationship: Y is 2.7~2.

9.

6. A high temperature resistant, low moisture absorption, flame retardant PA6T composition according to claim 1, characterized in that: The diethyl aluminum hypophosphite is 5 to 10 parts by weight.

7. The high temperature resistant, low moisture absorption, flame retardant PA6T composition according to claim 1, characterized in that: The diethyl aluminum hypophosphite is 5 to 7 parts by weight.

8. The high temperature resistant, low moisture absorption, flame retardant PA6T composition according to claim 1, characterized in that: The flame retardant synergist is selected from one or more of borates and metal oxides.

9. The high temperature resistant, low moisture absorption, flame retardant PA6T composition according to claim 1, characterized in that: The flame retardant synergist is present in an amount of 1 to 15 parts by weight.

10. The high temperature resistant, low moisture absorption, flame retardant PA6T composition according to claim 1, characterized in that: The flame retardant synergist is 3 to 10 parts by weight.

11. The high temperature resistant, low moisture absorption, flame retardant PA6T composition according to claim 1, characterized in that: The flame retardant synergist is 5 parts by weight.

12. The high temperature resistant, low moisture absorption, flame retardant PA6T composition according to claim 8, characterized in that: The borate is selected from zinc borate, and the metal oxide is selected from one or more of zinc oxide and aluminum oxide.

13. The high temperature resistant, low moisture absorption, flame retardant PA6T composition according to claim 1, characterized in that: The PA6T material is one or more of PA6T / 6, PA6T / 66, and PA6T / 6I.

14. The method for preparing a high temperature resistant, low moisture absorption, flame retardant PA6T composition according to any one of claims 1 to 13, characterized in that: The following steps are involved: (1) Add 100 parts by weight of PA6T material, 10-30 parts by weight of diethyl aluminum hypophosphite, 0-20 parts by weight of flame retardant synergist, 0-5 parts by weight of antioxidant, 0-5 parts by weight of lubricant, and 0-20 parts by weight of glass fiber into a high-speed mixer and stir to mix evenly; (2) adding the uniformly mixed materials into the twin-screw extruder from the main feed port of the twin-screw extruder, and performing melt mixing and extrusion granulation to obtain the high-temperature resistant, low-hygroscopicity flame-retardant PA6T composition.

15. Use of the high temperature resistant, low moisture absorption and flame retardant PA6T composition according to claims 1 to 13 in the preparation of electronic connectors.

16. An electronic connector, characterized in that: The invention comprises a high temperature resistant, low moisture absorption and flame retardant PA6T composition as described in claims 1 to 13.

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