Semi-aromatic polyamide composition as well as preparation method and application thereof

Abstract

The invention discloses a semi-aromatic polyamide composition, which is prepared from the following components in parts by weight: 40 to 75 parts of PA10T / X; 5-15 parts of a polyamide elastomer; 15-40 parts of a white filler; 5-20 parts of a reinforcing filler; and 0.5 to 2.5 parts of hydroxyl metal salt. According to the semi-aromatic polyamide composition, by adding the polyamide elastomer and the hydroxyl metal salt, the initial light reflectivity can be obviously improved, the binding force of the composition and epoxy glue can be further improved, and the semi-aromatic polyamide composition has rapid forming performance and is suitable for rapid forming of super multiple mold cavities.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and particularly to a semi-aromatic polyamide composition, a preparation method thereof, and an application thereof. Background Art

[0002] An LED light source mainly consists of a semiconductor chip, an LED light source reflection bracket, a gold wire, and a packaging glue. The LED light source reflection bracket is the "skeleton" of the LED light source and also a functional component. During the LED packaging process, it needs to go through die bonding, wire bonding, and curing of the packaging glue, integrating other materials and components. The LED reflection bracket needs to reflect the light emitted by the LED chip at a certain angle to reduce light loss, and then pass through packaging materials such as epoxy resin or silica gel to form a light source for LED lighting or display. The material of the LED reflection bracket is a core material for LED lighting, directly related to the performance and lifespan of the LED light source.

[0003] In LED displays, epoxy-based glue is mainly used for packaging. The adhesion between the epoxy-based glue and the reflection bracket material is directly related to the airtightness of the lamp beads and the lifespan of the display. If the adhesion between the glue and the reflection bracket material is poor, it is easy to cause the glue to peel off from the material, resulting in water vapor entering the lamp beads from the interface between the glue and the bracket material during the use of the display, causing the lamp beads to die and affecting the lifespan of the display.

[0004] Currently, more than 50% of the dead lamp failures of display lamp beads are due to the bonding problem between the glue and the bracket material. Therefore, the adhesion between the glue and the bracket plastic material is a crucial performance.

[0005] In order to improve the airtightness of the lamp beads and reduce the dead lamps of the display, and at the same time improve the cleanliness of the display and the electrostatic safety during the packaging process, for the LED light source reflection brackets applied to outdoor lighting and displays, on the one hand, it is necessary to improve the adhesion between the bracket plastic and the packaging glue, and at the same time, the LED reflection bracket material is required to have permanent antistatic performance. In addition, it is necessary to maintain the high initial reflectivity and yellowing resistance of the LED reflection bracket material. At the same time, the LED reflection bracket molding die is a multi-cavity (more than 2000 cavities per mold) and fast (molding cycle within 15 s) molding, and attention needs to be paid to the molding efficiency of the LED reflection bracket material. Summary of the Invention

[0006] The purpose of the present invention is to overcome the above technical defects and provide a semi-aromatic polyamide composition with the advantages of high light reflectivity, strong bonding force with epoxy glue, and fast molding, a preparation method thereof, and an application thereof.

[0007] A semi-aromatic polyamide composition, by weight, comprises the following components: 40 - 75 parts of PA10T / X; 5 - 15 parts of polyamide elastomer; White filler: 15 - 40 parts; Reinforcing filler: 5 - 20 parts; Metal hydroxide salt: 0.5 - 2.5 parts; Among them, for PA10T / X based on the molar percentage of PA10T / X, the content of 10T unit is 40 - 70 mol%, the content of X unit is 30 - 60 mol%, and the X unit is not 10T; among them, the X unit is composed of a diacid unit and a diamine unit, the diacid unit is selected from at least one of terephthalic acid unit, isophthalic acid unit, 1,6 - hexanedioic acid, 1,10 - decanedioic acid unit, and the diamine unit is selected from at least one of 1,6 - hexanediamine unit, 1,9 - nonanediamine unit, 2 - methyl - 1,5 - pentanediamine unit, 2 - methyl - 1,8 - octanediamine unit, 1,10 - decanediamine unit, 1,12 - dodecanediamine unit.

[0008] Preferably, in the PA10T / X, the content of 10T unit is 50 - 60 mol%, and the content of X unit is 40 - 50 mol%.

[0009] Specifically, PA10T / X can be PA10T / 10I, PA10T / 6T, PA10T / 66, PA10T / 1010, PA10T / 610, PA10T / 612, PA10T / 12T, etc.

[0010] In the semi - aromatic polyamide composition of the present invention, PA10T / X accounts for not less than 30 wt% of the total weight. The content of PA10T / X can be 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, etc., the content of polyamide elastomer can be 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, etc., the content of white filler can be 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, etc., the content of reinforcing filler can be 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, etc., and the content of metal hydroxide salt can be 0.5 parts, 0.7 parts, 0.9 parts, 1.1 parts, 1.3 parts, 1.5 parts, 1.7 parts, 1.9 parts, 2.1 parts, 2.3 parts, 2.5 parts, etc.

[0011] The PA10T / X resin of the present invention can be a commercially available product or can be synthesized by itself. Those skilled in the art can conventionally select the synthesis method of PA10T / X resin. The synthesis method of PA10T / X resin includes but is not limited to the following methods: (1) Pre-polymerization: The polymerization monomers (dicarboxylic acid, diamine), capping agent (which can be benzoic acid) and deionized water are put into a stainless-steel high-pressure reactor equipped with mechanical stirring. After evacuating the air and replacing it with N2 three times, the temperature is raised and stirring is started. The temperature is raised to 170 - 190 °C at a heating rate of 4 - 6 °C / min, and after maintaining the temperature for 1 - 2 hours, the temperature is raised to 260 - 280 °C at a heating rate of 1 - 3 °C / min, then slowly stirred and the temperature is maintained for 3 - 5 h to allow the pre-polymerization reaction to proceed fully. After the temperature maintenance ends, the temperature is slowly raised to 270 - 290 °C, and water is drained until normal pressure is reached. When the pressure drops to normal pressure, the drain valve is closed, the reaction ends, and the product is discharged after cooling to room temperature.

[0012] (2) Solid-phase viscosity increase: The material prepared in the pre-polymerization process is put into a vacuum rotary drum. The rotation speed of the rotary drum is set at 10 - 15 r / min, and the vacuum degree is set at 25 - 35 Pa. The temperature is raised at a rate of 15 - 25 °C / min. When the temperature reaches 260 - 270 °C, a sample is taken to test the viscosity, and the discharge end point is determined according to the viscosity (or number-average molecular weight) result.

[0013] The number-average molecular weight of the PA10T / X resin described is 2000 - 25000. The test method for the number-average molecular weight is a conventional method. Specifically, the number-average molecular weight (Mn) of the PA10T / X resin sample is determined by gel permeation chromatography (GPC). Agilent HPLC-1260 high-performance liquid chromatograph, configured with: Eppendorf column oven, Shodex KF-801, 802, 802.5 and 803 gel permeation chromatography columns, differential detector, G7129A automatic sampler. The molecular weight of the resin is determined under the condition of using hexafluoroisopropanol as the mobile phase and a column temperature of 40 °C. The data is processed using the cirrus software of the chromatographic workstation to obtain the number-average molecular weight distribution Mn.

[0014] The semi-aromatic polyamide composition described has a half-height width of the crystallization peak ΔT1 / 2 of 4 - 16 °C measured by differential scanning calorimetry at a cooling rate of 20 °C / min after heating from 30 °C to 350 °C at a rate of 20 °C / min in a nitrogen atmosphere and maintaining the temperature for 2 min.

[0015] Optionally, the half-height width of the crystallization peak of the PA10T / X resin, ΔT1 / 2, is 4 - 16 °C.

[0016] The polyamide elastomer described is selected from at least one of polyester-based polyamide elastomers and polyether-based polyamide elastomers. The hard segment in the polyamide elastomer can be PA1012, PA11, PA12, PA1010, PA1212, PA1213, PA612, PA6, etc.

[0017] The white filler described above is selected from at least one of titanium dioxide and zinc sulfide, and the average particle size of the white filler is 0.1 - 0.5 microns.

[0018] The reinforcing filler described above is selected from at least one of wollastonite, potassium titanate, kaolin, and talcum powder, and potassium titanate is preferred.

[0019] The average particle size of the wollastonite, potassium titanate, kaolin, and talcum powder is 0.1 - 15 microns.

[0020] The above average particle size is tested by a laser particle size analyzer.

[0021] The metal hydroxide salt of hydroxide is selected from metal hydroxides of Group ⅠA, ⅡA, and ⅢA, and preferably at least one of magnesium hydroxide, calcium hydroxide, aluminum hydroxide, and sodium hydroxide. The average particle size of the metal hydroxide salt of hydroxide is 0.1 - 15 microns. Magnesium hydroxide is preferred. In one embodiment, the percentage by weight of the metal hydroxide salt of hydroxide in the semi-aromatic polyamide composition ranges from 0.3 - 3.7 wt%.

[0022] Whether to add 0 - 2 parts of additives can be selected according to actual conditions. The additives described above are selected from at least one of antioxidants, lubricants, and ultraviolet resistant agents.

[0023] The preparation method of the semi-aromatic polyamide composition of the present invention includes the following steps: adding each component into a mixer and mixing evenly, and then extruding and granulating through a twin-screw extruder to obtain the semi-aromatic polyamide composition; wherein the screw temperature range is 280 - 330 °C and the rotation speed is 400 - 500 r / min.

[0024] An LED reflection bracket prepared from the semi-aromatic polyamide composition of the present invention.

[0025] An LED light source includes an LED reflection bracket prepared from the semi-aromatic polyamide composition of the present invention. The LED reflection bracket is encapsulated with an epoxy resin adhesive and is formed by multi-mode cavity processing.

[0026] The present invention has the following beneficial effects: In the present invention, the polyamide elastomer interacts with the epoxy glue to improve the bonding force with the epoxy glue; the acid absorption effect of the metal hydroxide salt can not only significantly improve the initial light reflectivity, but also, as a basic substance, the metal hydroxide salt can react with the epoxy groups in the epoxy resin to promote the curing process of the epoxy resin. In the curing reaction, the metal hydroxide salt can lower the reaction activation energy, increase the reaction rate, thereby accelerating the curing process, improving the curing efficiency of the epoxy resin, and further enhancing the bonding force between the composition and the epoxy glue. Moreover, the semi-aromatic polyamide composition of the present invention has rapid moldability and is suitable for ultra-high multi-cavity rapid molding. Therefore, the semi-aromatic polyamide composition of the present invention is suitable for preparing LED reflection brackets. Description of the Drawings

[0027] Figure 1 : Dimensions of the sample during the glue adhesion force test. Detailed Embodiments

[0028] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that those of ordinary skill in the art can make several modifications and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0029] The raw materials used in the examples and comparative examples of the present invention are as follows: 10T unit content, mol% Number-average molecular weight <![CDATA[ΔT 1 / 2 , °C]]> PA10T / 10I-1 40 9100 4.5 PA10T / 10I-2 50 8900 12.0 PA10T / 10I-3 60 8300 15 PA10T / 10I-4 70 9500 13.0 PA10T / 10I-5 30 9400 3.8 PA10T / 10I-6 80 10500 17.1 PA10T / 1010-1 40 9800 4.3 PA10T / 1010-2 50 10300 7.6 PA10T / 1010-3 60 10800 11.9 PA10T / 1010-4 70 9600 13.2 PA10T / 1010-5 30 8800 3.7 PA10T / 1010-6 80 7500 15.1 PA10T / 6T 60 13600 10.3 PA10T / 612 50 6400 8.2 PA10T / 610 55 22700 9.4 The above polyamide resin is a self-made raw material.

[0030] Polyamide elastomer A: The polyamide hard segment is PA12, Pebax® 4533 from Arkema, France; Polyamide elastomer B: The polyamide hard segment is PA12, WHE-4011 from Wanhua Chemical; Polyamide elastomer C: The polyamide hard segment is PA11, Pebax® Rnew 25R53 SP 01, from Arkema France; Polyamide elastomer D: The polyamide hard segment is PA6, AS5505, from Beijing Xuyang Technology; Titanium dioxide was purchased from Longbai, and the required average particle size was obtained by screening: Titanium dioxide A: The average particle size is 0.11 μm; Titanium dioxide B: The average particle size is 0.50 μm; Zinc sulfide: Sachtolith HD-S, with an average particle size of 0.14 μm, purchased from Sachtleben Chemie GmbH, Germany; Wollastonite: The average particle size is 12 μm; Potassium titanate: Nantong Aoxin Electronics Co., Ltd., average particle size is 3 - 5μm; Kaolin: Forsman Technology (Beijing) Co., Ltd., average particle size is 0.3μm; Magnesium hydroxide: Hefei Zhongke Flame Retardant New Materials Co., Ltd., average particle size is 0.4 - 2μm; Calcium hydroxide: Jiangxi Chuangxian Fine Calcium Co., Ltd., average particle size is 10μm; Aluminum hydroxide: Aluminum Corporation of China H - WF - 10, average particle size 0.8μm.

[0031] Preparation method of semi - aromatic polyamide composition in examples and comparative examples: Add each component into a mixer and mix evenly, then extrude and pelletize through a twin - screw extruder to obtain the semi - aromatic polyamide composition; among them, the screw temperature range is 280 - 330°C and the rotation speed is 450 r / min.

[0032] Each test method: (1) Half - height width ΔT of the crystallization peak of the semi - aromatic polyamide composition 1 / 2 : Use a differential scanning calorimeter manufactured by NETZSCH. Heat from 30°C to 345°C at a rate of 20°C / min in a nitrogen atmosphere, keep it at a constant temperature for 2 min, then cool at a cooling rate of 20°C / min. Set the crystallization peak temperature at this time as the crystallization temperature Tc (°C), and half of the measured peak width temperature is defined as the half - height width ΔT of the crystallization peak. 1 / 2 .

[0033] (2) Reflectivity: A test piece with a length of 60 mm, a width of 60 mm, and a thickness of 1 mm prepared by injection molding the semi - aromatic polyamide composition. Use a Color Eye 7000A color difference meter to measure the reflectivity of the test piece to light with a wavelength of 460 nm.

[0034] (3) Glue adhesion test: Inject plastic into a sample with the dimensions shown in the attached drawings of the specification. Then pour epoxy glue into the grooves of two splines, clamp it with a clip, bake at 150°C for 8 h, cool for more than 4 h, and then use a universal testing machine to break the bonded splines at the bonded part to measure the glue - bonded shear stress, with the unit of MPa.

[0035] Table 1: Component ratios (parts by weight) and test results of semi - aromatic polyamide compositions in Examples 1 - 7 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 PA10T / 10I-1 40 60 75 60 60 60 60 Polyamide elastomer A 5 10 15 10 Polyamide elastomer B 10 Polyamide elastomer C 10 Polyamide elastomer D 10 Titanium dioxide A 15 30 40 30 30 30 Titanium dioxide B 30 Wollastonite 5 10 20 10 10 10 10 Magnesium hydroxide 0.5 1.5 2.5 1.5 1.5 1.5 1.5 <![CDATA[Full width at half maximum of crystallization peak ΔT 1 / 2 , °C]]> 5.3 5.8 6.2 5.8 5.3 5.5 5.9 460nm reflectivity, % 92.0 93.5 93.6 93.2 93.4 92.5 92.8 Glue adhesion 30.0 35.3 38.5 35.8 33.8 34.2 36.6 It can be seen from Examples 2 / 4 - 6 that the polyamide elastomer is preferably a polyester - type polyamide elastomer.

[0036] Table 2: Component ratios (parts by weight) and test results of semi - aromatic polyamide compositions in Examples 7 - 11 Example 7 Example 8 Example 9 Example 10 Example 11 PA10T / 10I-1 60 60 60 60 60 Polyamide elastomer A 10 10 10 10 10 Titanium dioxide A 30 30 30 30 Zinc sulfide 30 Wollastonite 10 10 10 Potassium titanate 10 Kaolin 10 Magnesium hydroxide 1.5 1.5 1.5 Calcium hydroxide 1.5 Aluminum hydroxide 1.5 <![CDATA[Full width at half maximum of the crystallization peak ΔT 1 / 2 ,°C]]> 6.2 5.4 5.9 6.2 5.6 460nm reflectivity, % 91.6 94.1 92.5 93.5 93.2 Glue adhesion 39.1 40.6 36.5 31 33 As can be seen from Example 2 / 7, when the white filler is selected from zinc sulfide, the bonding force with the glue is better.

[0037] As can be seen from Examples 2 / 8 - 9, when the reinforcing filler is preferably potassium titanate, both the reflectivity and the bonding force with the glue are better.

[0038] As can be seen from Examples 2 / 10 / 11, the metal hydroxide salt is preferably magnesium hydroxide.

[0039] Table 3: Composition ratios (parts by weight) and test results of each component of the semi - aromatic polyamide composition in Examples 12 - 18 Example 12 Example 13 Example 14 Example 15 Example 16 Example 17 Example 18 PA10T / 10I-2 60 PA10T / 10I-3 60 PA10T / 10I-4 60 PA10T / 1010-1 60 PA10T / 1010-2 60 PA10T / 1010-3 60 PA10T / 1010-4 60 Polyamide elastomer A 10 10 10 10 10 10 10 Titanium dioxide A 30 30 30 30 30 30 30 Wollastonite 10 10 10 10 10 10 10 Magnesium hydroxide 1.5 1.5 1.5 1.5 1.5 1.5 1.5 <![CDATA[Full width at half maximum of the crystallization peak ΔT 1 / 2 , °C]]> 12.3 15.1 13.4 4.8 8.1 12.4 13.6 460nm reflectivity, % 93.8 93.9 93.2 93.6 94.3 93.7 93.1 Glue adhesion 37.9 38.4 37.1 36.9 38.4 37.5 36.9 As can be seen from Examples 2 / 12 - 13 and Examples 15 - 18, when the content of the 10T unit is 50 - 60 mol% and the content of the X unit is 40 - 50 mol%, the bonding force with the glue is stronger and the light reflectivity is also significantly higher.

[0040] Table 4: Composition ratios (parts by weight) and test results of each component of the semi - aromatic polyamide composition in Examples 19 - 21 Example 19 Example 20 Example 21 PA10T / 6T 60 PA10T / 612 60 PA10T / 610 60 Polyamide elastomer A 10 10 10 Titanium dioxide A 30 30 30 Wollastonite 10 10 10 Magnesium hydroxide 1.5 1.5 1.5 <![CDATA[Full width at half maximum of the crystallization peak ΔT 1 / 2 , °C]]> 10.8 8.9 9.8 460nm reflectivity, % 93.6 94.1 93.6 Glue adhesion 37.1 36.5 35.9 Table 5: Composition ratios (parts by weight) and test results of each component of the semi - aromatic polyamide composition in Comparative Examples 1 - 4 Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 PA10T / 10I-5 60 PA10T / 10I-6 60 PA10T / 1010-5 60 PA10T / 1010-6 60 Polyamide elastomer A 10 10 10 10 Titanium dioxide A 30 30 30 30 Wollastonite 10 10 10 10 Magnesium hydroxide 1.5 1.5 1.5 1.5 <![CDATA[Full width at half maximum of crystallization peak ΔT 1 / 2 , °C]]> 3.9 19.2 3.6 16.1 460nm reflectivity, % 90.6 91.1 91.0 91.5 Glue adhesion 23 25 28 21 As can be seen from Comparative Examples 1 - 4, when the polyamide repeating unit is not within the scope of the present invention, the full width at half maximum of the crystallization peak of the semi - aromatic polyamide composition is not within the scope of the present invention, and the bonding force with the glue is poor.

[0041] Table 6: Composition ratios (parts by weight) and test results of each component in Comparative Examples 5 - 7 Comparative example 5 Comparative example 6 Comparative example 7 PA10T / 10I-1 60 60 60 Polyamide elastomer A 0 10 10 Titanium dioxide A 30 30 30 Wollastonite 10 10 10 Magnesium hydroxide 1.5 0 4 <![CDATA[Full width at half maximum of crystallization peak ΔT 1 / 2 , °C]]> 6.2 6.2 6 460nm reflectivity, % 93 89 89.5 Glue adhesion 15 32 25 As can be seen from Comparative Example 5, when the polyamide elastomer is not contained, the bonding force with the glue is poor.

[0042] As can be seen from Comparative Example 6, when magnesium hydroxide is not contained, the light reflectivity is low.

[0043] As can be seen from Comparative Example 7, when the content of magnesium hydroxide is too high, it will instead reduce the light reflectivity and the bonding force with the glue.

Claims

1. A semi-aromatic polyamide composition, characterized in that: By weight, it includes the following components: PA10T / X 40-75 parts; Polyamide elastomer 5-15 parts; 15-40 parts of white filler; 5-20 parts of reinforcing filler; 0.5-2.5 parts of metal hydroxide salt; Wherein, based on the molar percentage of PA10T / X, the content of 10T unit is 40-70 mol%, the content of X unit is 30-60 mol%, and the X unit is not 10T; wherein, the X unit is composed of a diacid unit and a diamine unit, the diacid unit is selected from at least one of terephthalic acid unit, isophthalic acid unit, 1,6-hexanediamine unit, and 1,10-decanediacid unit, and the diamine unit is selected from at least one of 1,6-hexanediamine unit, 1,9-nonanediamine unit, 2-methyl-1,5-pentanediamine unit, 2-methyl-1,8-octanediamine unit, 1,10-decanediamine unit, and 1,12-dodecanediamine unit.

2. The semi-aromatic polyamide composition according to claim 1, characterized in that In the PA10T / X, the 10T unit content is 50-60 mol%, and the X unit content is 40-50 mol%.

3. The semi-aromatic polyamide composition according to claim 1, characterized in that The semi-aromatic polyamide composition is subjected to differential scanning calorimetry. After the temperature is raised from 30°C to 350°C at a rate of 20°C / min and kept constant for 2 minutes in a nitrogen atmosphere, the half-height width ΔT1 / 2 of the crystallization peak measured at a cooling rate of 20°C / min is 4-16°C.

4. The semi-aromatic polyamide composition according to claim 1, characterized in that The white filler is selected from at least one of titanium dioxide and zinc sulfide, and the average particle size of the white filler is 0.1-0.5 microns.

5. The semi-aromatic polyamide composition according to claim 1, characterized in that The reinforcing filler is selected from at least one of wollastonite, potassium titanate, kaolin and talc, preferably potassium titanate.

6. The semi-aromatic polyamide composition according to claim 1, characterized in that The hydroxide metal salt is selected from metal hydroxides of Groups IA, IIA, and IIIA, preferably at least one of magnesium hydroxide, calcium hydroxide, aluminum hydroxide, and sodium hydroxide, more preferably magnesium hydroxide; the average particle size of the hydroxide metal salt is 0.1-15 microns.

7. The semi-aromatic polyamide composition according to claim 1, characterized in that By weight, the invention also includes 0-2 parts of auxiliary agents, wherein the auxiliary agents are selected from at least one of antioxidants, lubricants and UV-resistant agents.

8. The method for preparing the semi-aromatic polyamide composition according to any one of claims 1 to 7, characterized in that: The following steps are involved: The components are added into a mixer and mixed evenly, and then extruded and granulated by a twin-screw extruder to obtain a semi-aromatic polyamide composition.

9. An LED reflective bracket prepared according to the semi-aromatic polyamide composition according to any one of claims 1 to 7.

10. An LED light source, comprising the LED reflective bracket according to claim 9, wherein the LED reflective bracket is encapsulated with an epoxy resin adhesive and is formed by multi-cavity processing.

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