POLYAMIDE COMPOSITE MATERIAL AND PREPARATION METHOD THEREOF

Abstract

The present invention provides a polyamide composite material, which includes the following components in parts by weight: 25-85 parts of a polyamide resin; 10-50 parts of a glass fiber; 5-25 parts of polytetrafluoroethylene; and 0.1-2 parts of at least one of a K/Na/Ca/Mg/Ba/Zn/Li/Al salt of montanic acid. The montanate can effectively inhibit free hydrogen fluoride in the polytetrafluoroethylene, thereby effectively inhibiting free silicon in the glass fiber and improving the electrical performance of the material.

Claims

1. A polyamide composite material, comprising following components in parts by weight: 25-85 parts of a polyamide resin; 10-50 parts of a glass fiber; 5-25 parts of polytetrafluoroethylene; and 0.1-2 parts of a salt of montanic acid, wherein the salt of montanic acid is selected from at least one of a K salt of montanic acid, a Na salt of montanic acid, a Ca salt of montanic acid, a Mg salt of montanic acid, a Ba salt of montanic acid, a Zn salt of montanic acid, a Li salt of montanic acid, a Al salt of montanic acid.

2. The polyamide composite material according to claim 1, wherein the polyamide resin is selected from polyamide obtained by polycondensation of at least one aliphatic dicarboxylic acid with at least one aliphatic diamine or cyclic diamine, or polyamide obtained by polycondensation of at least one aromatic dicarboxylic acid with at least one aliphatic diamine, or polyamide obtained by polycondensation of at least one amino acid or lactam with itself, or a mixture or copolyamide thereof

3. The polyamide composite material according to claim 2, wherein the polyamide resin is selected from at least one of PA6, PA66, PA56, PA610, PA612, PA510, PA46 and PAST.

4. The polyamide composite material according to claim 1, wherein the salt of montanic acid is selected from at least one of sodium montanate and magnesium montanate.

5. The polyamide composite material according to claim 1, wherein the glass fiber is selected from at least one of an E glass fiber, a H glass fiber, a glass fiber, a S glass fiber, a D glass fiber and a C glass fiber.

6. The polyamide composite material according to claim 5, wherein the glass fiber is the E glass fiber.

7. The polyamide composite material according to claim 1, wherein the glass fiber is selected from at least one of a long glass fiber and a chopped glass fiber.

8. The polyamide composite material according to claim 1, wherein the polytetrafluoroethylene has a molecular weight in a range of 10,000-10,000,000 g/mol.

9. The polyamide composite material according to claim 1, wherein a content of free hydrogen fluoride in the polytetrafluoroethylene is less than 300 ppm based on a total mass of the polytetrafluoroethylene.

10. A method for preparing the polyamide composite material according to claim 1, comprising following steps: mixing the polyamide resin, the the salt of montanic acid and the polytetrafluoroethylene uniformly, and then granulating by extruding with a twin-screw extruder to obtain the polyamide composite material, wherein a screw temperature ranges from 220-270° C., and a rotating speed is 300-450 rpm, wherein in the twin-screw extruder, a chopped glass fiber is added in a main feeding, and a long glass fiber is added in a side feeding.

11. The polyamide composite material according to claim 5, wherein the glass fiber is selected from at least one of a long glass fiber and a chopped glass fiber.

12. The polyamide composite material according to claim 6, wherein the glass fiber is selected from at least one of a long glass fiber and a chopped glass fiber.

Description

DESCRIPTION OF THE EMBODIMENTS

[0024] The present invention will be described in detail hereafter with reference to specific examples. The following examples will facilitate further understanding of the present invention by those skilled in the art, but will not limit the present invention in any way. It should be pointed out that for those of ordinary skills in the art, several modifications and improvements can be made without departing from the concept of the present invention. These all belong to the claimed scope of the present invention.

[0025] The raw materials used in the present invention come from commercially available products:

[0026] PA66: PA66EP-158, available from Huafon Group, Zhejiang;

[0027] PA6: HY2800A, available from Haiyang Chemical Fiber Group Co Ltd.;

[0028] PA10T: VESTAMID HTplus M1000, available from Evonik Industries AG;

[0029] PA-MXD6: RENY 1002H, available from Mitsubishi Chemical Corporation; Glass fiber 1: an E glass fiber, ECS301HP-3-H, chopped, available from Chongqing Polycomp International Corporation;

[0030] Glass fiber 2: a S glass fiber, S-1 HM435TM-10-3.0, chopped.

[0031] Polytetrafluoroethylene 1: having a content of free hydrogen fluoride of 500 ppm; and a molecular weight of: 3.5×10.sup.5-3.9×10.sup.5 g/mol.

[0032] Polytetrafluoroethylene 2: having a content of free hydrogen fluoride of 300 ppm; and a molecular weight of: 3.3×10.sup.5-3.8×10.sup.5 g/mol.

[0033] Polytetrafluoroethylene 3: having a content of free hydrogen fluoride of 30 ppm; and a molecular weight of: 3.4×10.sup.5-3.9×10.sup.5 g/mol.

[0034] Sodium montanate, magnesium montanate, aluminum montanate and calcium montanate are commercially available.

[0035] Calcium stearate: available from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0036] fatty acid ester 1: LOXIOL G 32, available from EmeryOleochemicals LLC; and

[0037] fatty acid ester 2: Loxiol EP-PTS, available from EmeryOleochemicals LLC.

[0038] A method for preparing the polyamide compositions of Embodiments and Comparative Examples: mixing a polyamide resin, a K/Na/Ca/Mg/Ba/Zn/Li/Al salt of montanic acid (or other lubricants) and polytetrafluoroethylene uniformly, and then granulating by extruding with a twin-screw extruder (main feeding of a chopped glass fiber/side feeding of a long glass fiber) to obtain the polyamide composite material, wherein a screw temperature ranges from 220-270° C., and a rotating speed is 300-450 rpm.

[0039] Determination of free silicon content: referring to GB/T 23842-2009 (General method for the determination of silicon content of inorganic chemicals—Reduced molybdosilicate spectrophotometric method), the determination of free silicon was carried out by silicon molybdenum blue spectrophotometry: 1 g of a crushed sample was taken and put in a plastic flask, and added with 15 ml of n-hexane for extraction for 24 h, and then the extract liquor was transferred into a silver crucible. The silver crucible was added with 2 ml of a 50% sodium hydroxide solution, placed on an electric heating plate, and heated to 500° C., for 40 min for inorganic transformation of free silicon. The inorganic product was dissolved in 20 ml of distilled water, then acidified to a pH value of about 2-3 by adding a 5 mol/L sulfuric acid (analytically pure) solution, and then added with 2 ml of a 5% ammonium molybdate (analytically pure) solution and 0.2 ml of a 1% stannous chloride (analytically pure) solution for a color development reaction. The developed solution was taken and tested with an ultraviolet spectrophotometer, and the test result was compared with an established silicon standard line to get the silicon content. The establishment of the silicon standard line: a silicon standard solution was taken and formulated into solutions with silicon concentrations of 0.1, 0.25, 0.50, 1.00, 2.0 ppm with deionized water, and tested with the ultraviolet spectrophotometer to establish the standard line, with the wavelength being taken at 810 nm. The silicon standard line conformed to y=0.535x+0.013, R.sup.2=0.999.

TABLE-US-00001 TABLE 1 Proportion (parts by weight) and test results of polyamide compositions of Embodiments 1-6 Embodiment Embodiment Embodiment Embodiment Embodiment Embodiment 1 2 3 4 5 6 PA6 65 25 65 PA66 65 40 PA10T 65 MXD6 65 Glass fiber 1 20 20 20 20 20 20 Glass fiber 2 Polytetrafluo- 15 15 15 15 15 15 roethylene 3 Sodium 0.2 0.2 0.2 0.2 0.2 0.6 montanate Content of 0.2 0.3 0.5 0.4 0.3 0.1 free silicon, in ppm

[0040] It could be seen from Embodiments 1 and 6 that the addition of sodium montanate could effectively reduce the content of the free silicon.

TABLE-US-00002 TABLE 2 Proportion (parts by weight) and test results of polyamide compositions of Embodiments 7-12 Embodiment Embodiment Embodiment Embodiment Embodiment Embodiment 7 8 9 10 11 12 PA6 65 65 65 65 65 65 Glass fiber 1 20 20 20 20 20 Glass fiber 2 20 Polytetrafluor- 15 15 15 15 oethylene 3 Polytetrafluor- 15 oethylene 2 Polytetrafluor- 15 oethylene 1 Sodium 0.2 0.2 0.2 montanate Magnesium 0.2 montanate Aluminium 0.2 montanate Calcium 0.2 montanate Content of 0.3 0.5 0.6 0.3 0.5 0.6 free silicon, in ppm

[0041] It could be seen from Embodiments 1/7/8 that the content of the free silicon is decreased significantly when the polytetrafluoroethylene with a low content of free hydrogen fluoride was employed, which indicated that the free silicon in the polyimide composition was sourced from the corrosion of the hydrogen fluoride released from the polytetrafluoroethylene to the glass fiber.

[0042] It could be seen from Embodiments 1/9 that the E glass was preferred, which had less free silicon.

[0043] It could be seen from Embodiments 1/10/11/12 that sodium montanate and magnesium montanate were preferred for optimum inhibition on free silicon.

TABLE-US-00003 TABLE 3 Proportion (parts by weight) and test results of polyamide compositions of Comparative Examples Comparative Comparative Comparative Comparative Comparative Comparative Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 PA6 65 65 65 65 65 65 Glass fiber 1 20 20 20 20 20 20 Polytetrafluor 15 15 15 15 15 15 -oethylene 3 Calcium 0.2 0.5 0.8 stearate Fatty acid 0.6 ester 1 Fatty acid 0.6 ester 2 Content of 2.2 2.0 1.9 2.3 2.0 2.4 free silicon, in ppm

[0044] It could be seen from Comparative Examples 1-6 that the content of free silicon could not be reduced by employing traditional lubricants such as calcium stearate, fatty acid ester and the like. The production of free silicon could not be effectively inhibited by the addition of calcium stearate and fatty acid ester.