Polyamide molding composition and its method of manufacture and use

Abstract

Provided is a polyamide molding composition comprising, as components, 40 to 75 parts by weight of a PAXC / YC resin, 30 to 60 parts by weight of a white pigment, and 1.5 to 5% of a dispersant relative to the weight parts of the white pigment, wherein the PAXC / YC resin has, expressed in mole percentages based on the PAXC / YC, a content of XC units of 60 to 100 mol % and a content of YC units of 0 to 40 mol %, the XC units consisting of 1,4-cyclohexanedicarboxylic acid and diamine units, the diamine units being at least one selected from the group consisting of 1,9-nonanediamine units, 1,10-decanediamine units, and 1,12-dodecanediamine units, and the YC units consisting of 1,4-cyclohexanedicarboxylic acid and diamine units, the diamine units being at least one selected from the group consisting of aliphatic diamine units having 5 to 13 carbon atoms. The polyamide molding composition of the present invention has the advantages of being excellent in dispersibility of white pigments and having high reflectance and a high melting point when the white pigment is added in a normal amount.

Description

[Technical Field]

[0001] The present invention relates to the technical field of polymeric materials, in particular to polyamide molding compositions and to methods for their production and use. [Background technology]

[0002] An LED light source is primarily composed of a semiconductor chip, an LED light source reflector, gold wire, and encapsulation resin. The LED light source reflector is both the "skeleton" and functional component of the LED light source. The LED packaging process involves die bonding, wire bonding, and encapsulation resin curing on the LED light source reflector, and all other materials and components are integrated into it. The LED reflector reflects the light emitted from the LED chip at a specific angle, reducing light loss and allowing the light to pass through packaging materials such as epoxy resin and silica gel, thus forming the light source for LED lighting and displays. The material of the LED reflector is a core material in LED lighting and directly affects the performance and lifespan of the LED light source.

[0003] In lighting and backlight applications, the brightness of individual LED light sources is a crucial indicator for reducing the number of LED elements used and achieving energy conservation and environmental protection. The brightness of individual LED light sources is related not only to the chip output but also to the reflectivity of the LED light support. The higher the chip output, the higher the brightness of the individual LED, but the higher the melting point requirements for the LED light support. Furthermore, the higher the reflectivity of the LED light support, the higher the brightness of the individual LED light source. However, while conventional technology can improve surface whiteness and light reflectivity by adding ultra-high amounts of titanium dioxide (65 wt% or more), this reduces processability and easily creates unevenness on the surface of the LED light support, which in turn reduces light reflectivity and makes processing more difficult.

[0004] Conventional LED light source supports are primarily made from a combination of semi-aromatic, high-temperature-resistant polyamide materials, reinforcing fillers, and white pigments. However, because semi-aromatic polyamide materials contain unsaturated bonds in the benzene ring, they are susceptible to shear and heat during processing, which can lead to yellowing in the case of high-power LED light sources and affect the brightness of the material. Furthermore, in material systems with a large amount of white pigment added, the dispersibility of the white pigment affects the brightness of the material.

[0005] Chinese Patent CN102482492B discloses a reflector for LEDs, and also discloses a polyamide having dicarboxylic acid units containing 80 to 100 mol % of 1,4-cyclohexanedicarboxylic acid units and diamine units containing 50 to 100 mol % of aliphatic diamine units having 4 to 18 carbon atoms. This LED reflector is produced by irradiating light from a metal halide lamp, which has been filtered to transmit light of 295 nm to 780 nm in the air at 120°C, with an illuminance of 10 mW / cm at a wavelength of 300 to 400 nm. 2 After 336 hours of irradiation at a position where the reflectance of light with a wavelength of 460 nm is 90% or more. However, if it needs to be used as an LED reflector for a strong light source, a higher reflectance is required. Summary of the Invention

[0006] The polyamide molding composition according to the present invention comprises as components: 40 to 75 parts by weight of PAXC / YC resin; 30 to 60 parts by weight of a white pigment; 1.5 to 5% of a dispersant based on the weight of the white pigment; The PAXC / YC resin has a content of XC units of 60 to 100 mol % and a content of YC units of 0 to 40 mol %, expressed in mole percentage based on PAXC / YC, wherein the XC units are composed of 1,4-cyclohexanedicarboxylic acid (C) and diamine units X, and the diamine units X are at least one selected from the group consisting of 1,9-nonanediamine units, 1,10-decanediamine units, and 1,12-dodecanediamine units; the YC units are composed of 1,4-cyclohexanedicarboxylic acid (C) and diamine units Y, and the diamine units Y are at least one selected from aliphatic diamine units having 5 to 13 carbon atoms; the dispersant is at least one selected from the group consisting of calcium oxide and zinc oxide, the white pigment has an average particle size ranging from 0.10 to 0.50 μm, and the dispersant has an average particle size ranging from 1 to 6 μm; The polyamide molding composition has a dispersion coefficient α of the white pigment, measured using a three-dimensional X-ray microscope, of greater than 65%.

[0007] The polymerization method for PAXC / YC resin is as follows. Prepolymerization: The polymerization monomers (dicarboxylic acid, diamine), the end-capping agent benzoic acid, and deionized water were placed in a stainless steel high-pressure reactor equipped with a mechanical stirrer. After evacuating and flushing with nitrogen three times, the temperature was increased and stirring began. The temperature was raised at a rate of 4-6°C / min to 170-190°C and maintained at that temperature for 1-2 hours. After that, the temperature was increased at a rate of 1-3°C / min to 260-280°C and maintained at that temperature for 3-5 hours with slow stirring to allow the prepolymerization reaction to proceed fully. After the temperature was maintained, the temperature was gradually increased to 270-290°C and the water was discharged until atmospheric pressure was reached. Once the pressure had dropped to atmospheric pressure, the discharge valve was closed to terminate the reaction. The temperature was then lowered to room temperature and the materials were discharged. Solid Phase Thickening: The material prepared in the prepolymerization process is placed in a vacuum drum, and the drum speed is set to 10-15 r / min and the vacuum to 25-35 Pa. The temperature is increased at a rate of 15-25°C / min, and when the temperature reaches 260-270°C, a sample is taken and the viscosity is measured, and the end point of the material discharge is determined based on the viscosity result.

[0008] The aliphatic diamine having 5 to 13 carbon atoms is at least one selected from the group consisting of 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 2-methyl-1,8-octanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, and 1,13-tridecanediamine, and preferably, 2-methyl-1,8-octanediamine is selected as the aliphatic diamine having 5 to 13 carbon atoms.

[0009] When the content of XC units is less than 60 mol %, the melting point of the PAXC / YC resin is lower than 320°C.

[0010] Preferably, when the content of the white pigment is 45 to 60 parts by weight, the content of the dispersant is 3 to 4% relative to the parts by weight of the white pigment.

[0011] Preferably, the PAXC / YC resin has an XC unit content of 65 to 90 mol %, more preferably 70 to 79.99 mol %, expressed in mole percentage based on PAXC / YC.

[0012] Preferably, the average particle size of the white pigment is in the range of 0.15 to 0.35 μm, and preferably, the average particle size of the dispersant is in the range of 3 to 4 μm.

[0013] Preferably, when titanium white is selected as the white pigment, calcium oxide is selected as the dispersant, and when zinc sulfide is selected as the white pigment, zinc oxide is selected as the dispersant.

[0014] The polyamide molding composition has a total reflectance of more than 285% for red light with a wavelength of 650 nm, green light with a wavelength of 550 nm, and blue light with a wavelength of 450 nm.

[0015] Preferably, the polyamide molding composition has a total reflectance of more than 290% for red light with a wavelength of 650 nm, green light with a wavelength of 550 nm and blue light with a wavelength of 450 nm.

[0016] The melting point of the PAXC / YC resin of the present invention is higher than 320°C.

[0017] The method for producing a polyamide molding composition of the present invention includes the steps of adding each component to a mixer, mixing them uniformly, and then extruding and granulating them in a twin-screw extruder to obtain a polyamide molding composition, wherein the screw temperature range is 280 to 330°C and the screw rotation speed is 400 to 500 r / min. The polyamide molding composition of the present invention is used to manufacture LED reflector supports, and is particularly suitable for use in high-power LED reflectors. [Effects of the Invention]

[0018] The present invention has the following beneficial effects:

[0019] This invention uses PAXC / YC resin, which has a higher melting point, better yellowing resistance, and can withstand higher-power light sources. By selecting a specific content of dispersant, it can greatly promote the dispersion of white pigments (titanium white, zinc sulfide), and can significantly improve the total reflectance for red light with a wavelength of 650 nm, green light with a wavelength of 550 nm, and blue light with a wavelength of 450 nm (demonstrating that the LED reflector can achieve higher light source reflectance). This solves the drawback of powder materials being difficult to disperse due to the high viscosity of PAXC / YC resin. DETAILED DESCRIPTION OF THE INVENTION

[0020] The present invention will be described in detail below with reference to specific examples. The following examples are provided for the purpose of providing a better understanding of the present invention to those skilled in the art, and are not intended to limit the present invention in any way. Those skilled in the art may make some modifications and improvements without departing from the spirit of the present invention, and all such modifications and improvements are within the scope of the present invention.

[0021] The raw materials used in the examples and comparative examples of the present invention are as follows. PA10C / 5C: XC content 70mol%, where X is 1,10-decanediamine and Y is 1,5-pentanediamine, self-made, melting point 321℃ PA10C / 6C: XC content 70 mol%, where X is 1,10-decanediamine and Y is 1,6-hexanediamine, self-made, melting point 325℃ PA10C / 9C: XC content 70 mol%, where X is 1,10-decanediamine and Y is 1,9-nonanediamine, self-made, melting point 329°C PA10C / 12C-A: XC content 60 mol%, where X is 1,10-decanediamine and Y is 1,12-dodecanediamine, self-made, melting point 320°C PA10C / 12C-B: XC content 65 mol%, where X is 1,10-decanediamine and Y is 1,12-dodecanediamine, self-made, melting point 334°C PA10C / 12C-C: XC content 70 mol%, where X is 1,10-decanediamine and Y is 1,12-dodecanediamine, self-made, melting point 326°C PA10C / 12C-D: XC content 79.9 mol%, where X is 1,10-decanediamine and Y is 1,12-dodecanediamine, self-made, melting point 330°C PA10C / 12C-E: XC content 90 mol%, where X is 1,10-decanediamine and Y is 1,12-dodecanediamine, self-made, melting point 340°C PA10C: Homemade, melting point 355℃ PA10C / 12C-F: XC content 50 mol%, where X is 1,10-decanediamine and Y is 1,12-dodecanediamine, self-made, melting point 313°C PA10C / M8C: XC content 70 mol%, where X is 1,10-decanediamine and Y is 2-methyl-1,8-octanediamine, self-made, melting point 325°C PA9C / 5C: XC content 90 mol%, where X is 1,9-nonanediamine and Y is 1,5-pentanediamine, self-prepared, melting point 341 °C. PA9C / 6C: XC content 95 mol%, where X is 1,9-nonanediamine and Y is 1,6-hexanediamine, self-prepared, melting point 346°C PA9C / M8C: XC content 70 mol%, where X is 1,9-nonanediamine and Y is 2-methyl-1,8-octanediamine, self-prepared, melting point 322°C PA9C / 12C: XC content 65 mol%, where X is 1,9-nonanediamine and Y is 1,12-dodecanediamine, self-prepared, melting point 324°C PA9C: Homemade, melting point 350℃ PA12C / 5C: XC content 70 mol%, where X is 1,12-dodecanediamine and Y is 1,5-pentanediamine, self-made, melting point 327°C PA12C / 6C: XC content 85 mol%, where X is 1,12-dodecanediamine and Y is 1,6-hexanediamine, self-made, melting point 331℃ PA12C: Homemade, melting point 349℃ PA10T: Homemade, melting point 316℃ PA10T66: Homemade, melting point 295℃ Titanium white was purchased from Ryusen Hakuri Co., Ltd., and then sieved to obtain a product having the desired average particle size. Titanium White A: Average particle size 0.11 μm Titanium White B: Average particle size 0.15 μm Titanium White C: average particle size 0.35 μm Titanium White D: Average particle size 0.50 μm Titanium White E: Average particle size 0.06 μm Titanium White F: average particle size 0.65 μm Zinc sulfide: average particle size 0.14 μm, purchased from Sachtleben GmbH, Germany, Sachtolith HD-S. Calcium oxide was purchased from Zhuzhou Youfu New Material Technology Co., Ltd., and then sieved to obtain the desired average particle size. Calcium oxide A: average particle size 1.2 μm Calcium oxide B: average particle size 3.1 μm Calcium oxide C: average particle size 4.0 μm Calcium oxide D: average particle size 5.9 μm Calcium oxide E: average particle size 0.4 μm Calcium oxide F: average particle size 8.4 μm Zinc oxide: average particle size 0.5 μm. The polyamide molding compositions of the Examples and Comparative Examples were produced as follows: Each component was mixed uniformly in a mixer, then extruded and granulated in a twin-screw extruder to obtain a polyamide molding composition. The screw temperature range was 280-310-320-300-300-300-300-300-300-310-320-330°C, and the rotation speed was 400-500 r / min.

[0022] Test methods for each item (1) RGB light source reflectance: A test piece 60 mm long, 60 mm wide, and 1 mm thick was manufactured by injection molding using a polyamide molding composition. The reflectance of the test piece for light with wavelengths of 450 nm, 550 nm, and 650 nm was measured using a color difference meter, Color Eye 7000A. The reflectance of the RGB light source was calculated as F = Rf(450 nm) + Rf(550 nm) + Rf(650 nm). (2) Evaluation of white pigment dispersion: Using a 3D X-ray microscope (Tianjin Sanying Precision Instrument Co., Ltd., nanoVoxel 2000), material particles were scanned and imaged at a voxel resolution of 1.9 μm, and white pigment particles of different particle sizes were screened and counted stepwise. This resulted in the white pigment dispersion coefficient α (the ratio of the volume of white pigment particles to the total volume of 20,000 μm 3 The percentage of white pigment particles was less than 100%.

[0023] [Table 1]

[0024] From Examples 1 to 6, it was found that an increase in the calcium oxide content increases the dispersion coefficient of the polyamide molding composition, but if the dispersant content is too high, the reflectance of calcium oxide is low, so the reflectance decreases despite the high dispersion coefficient. Specifically, from Examples 3 to 6, it was found that when the white pigment content is 45 to 60 parts by weight, the dispersant content is preferably 3 to 4% relative to the parts by weight of the white pigment.

[0025] [Table 2]

[0026] As can be seen from Examples 3, 7, 8 and 9, the larger the particle size of titanium white, the higher the dispersion coefficient, but an average particle size of 0.15 to 0.35 μm is preferable because it further increases the reflectance.

[0027] As can be seen from Examples 7, 10, 11, and 12, when titanium white is selected as the white pigment, dispersibility improves when calcium oxide is selected as the dispersant, and when zinc sulfide is selected as the white pigment, dispersibility improves when zinc oxide is selected as the dispersant.

[0028] From Examples 9 and 13 to 15, it was found that when a dispersant having a preferable particle size was used, the dispersibility of the white pigment improved and the reflectance also increased.

[0029] [Table 3]

[0030] As can be seen from Examples 18 to 23, the content of XC units is preferably 65 to 90 mol %, and more preferably 70 to 79.99 mol %.

[0031] [Table 4]

[0032] It was found from Examples 24 to 32 that 2-methyl-1,8-octanediamine is preferable as the aliphatic diamine having 5 to 13 carbon atoms.

[0033] [Table 5]

[0034] As can be seen from Comparative Examples 1 to 3, the white pigment dispersant of the present invention is strongly affected by the resin base, and when other types of resin base are used, the dispersibility of the white pigment decreases, resulting in a lower reflectance.

[0035] [Table 6]

[0036] As can be seen from Comparative Examples 4 and 5, when the particle size of calcium oxide is too large or too small, it significantly affects the dispersion coefficient of the white pigment, resulting in a decrease in reflectance.

[0037] As can be seen from Comparative Examples 6 and 7, when the particle size of titanium white is too large or too small, the dispersion coefficient drops significantly, resulting in a low reflectance.

[0038] As can be seen from Comparative Examples 8 to 11, when the content of the dispersant is too much or too little, the dispersion coefficient drops significantly, resulting in a low reflectance.

Claims

1. A polyamide molding composition comprising as components: 40 to 75 parts by weight of PAXC / YC resin; 30 to 60 parts by weight of a white pigment; 1.5 to 5% of a dispersant based on the weight of the white pigment; The PAXC / YC resin has a content of XC units of 60 to 100 mol % and a content of YC units of 0 to 40 mol %, expressed in mole percentage based on PAXC / YC, the XC units being composed of 1,4-cyclohexanedicarboxylic acid and diamine units X, the diamine units X being at least one selected from the group consisting of 1,9-nonanediamine units, 1,10-decanediamine units, and 1,12-dodecanediamine units, the YC units being composed of 1,4-cyclohexanedicarboxylic acid and diamine units Y, the diamine units Y being at least one selected from aliphatic diamine units having 5 to 13 carbon atoms, the dispersant is at least one selected from the group consisting of calcium oxide and zinc oxide, the white pigment has an average particle size ranging from 0.10 to 0.50 μm, and the dispersant has an average particle size ranging from 1 to 6 μm; The polyamide molding composition is characterized in that the dispersion coefficient α of the white pigment measured using a three-dimensional X-ray microscope is greater than 65%.

2. 2. The polyamide molding composition according to claim 1, wherein the aliphatic diamine having 5 to 13 carbon atoms is at least one selected from the group consisting of 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 2-methyl-1,8-octanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, and 1,13-tridecanediamine, and preferably 2-methyl-1,8-octanediamine is selected as the aliphatic diamine having 5 to 13 carbon atoms.

3. 2. Polyamide molding composition according to claim 1, characterized in that when the content of the white pigment is 45 to 60 parts by weight, the content of the dispersant is 3 to 4% relative to the parts by weight of the white pigment.

4. 2. The polyamide molding composition according to claim 1, wherein the PAXC / YC resin has a content of XC units of 65 to 90 mol %, more preferably 70 to 79.99 mol %, expressed as a mole percentage based on PAXC / YC.

5. 2. The polyamide molding composition according to claim 1, wherein the white pigment has an average particle size in the range of 0.15 to 0.35 μm and the dispersant has an average particle size in the range of 3 to 4 μm.

6. 2. The polyamide molding composition according to claim 1, wherein calcium oxide is selected as the dispersant when titanium white is selected as the white pigment, and zinc oxide is selected as the dispersant when zinc sulfide is selected as the white pigment.

7. 7. The polyamide molding composition according to claim 3, wherein the polyamide molding composition has a total reflectance of more than 285% for red light with a wavelength of 650 nm, green light with a wavelength of 550 nm and blue light with a wavelength of 450 nm, and preferably has a total reflectance of more than 290% for red light with a wavelength of 650 nm, green light with a wavelength of 550 nm and blue light with a wavelength of 450 nm.

8. 2. The polyamide molding composition according to claim 1, wherein the PAXC / YC resin has a melting point greater than 320°C.

9. 9. A method for producing a polyamide molding composition according to claim 1, comprising the steps of adding each component to a mixer, mixing them uniformly, and then extruding and granulating them in a twin-screw extruder to obtain a polyamide molding composition, wherein the screw temperature is in the range of 280 to 330°C and the screw rotation speed is 400 to 500 r / min.

10. 9. Use of the polyamide molding composition according to any one of claims 1 to 8 for the production of an LED reflector support.

Images