Semi-aromatic polyamide composition, and preparation method therefor and use thereof

Abstract

Disclosed is a semi-aromatic polyamide composition, comprising the following components in parts by weight: 40-75 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 0.5-2.5 parts of a metal hydroxide. In the present invention, by adding the polyamide elastomer and the metal hydroxide, not only can the initial light reflectance be significantly improved, but the adhesion between the composition and an epoxy adhesive can also be further improved; furthermore, the semi-aromatic polyamide composition of the present invention has rapid forming performance and is suitable for rapid forming featuring an ultra-high mold cavity count.

Description

A semi-aromatic polyamide composition, its preparation method and application Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a semi-aromatic polyamide composition, its preparation method, and its application. Background Technology

[0002] LED light sources mainly consist of semiconductor chips, LED reflector brackets, gold wires, and encapsulating adhesive. The LED reflector bracket is the "skeleton" of the LED light source and also a functional component. The LED packaging process involves die bonding, wire bonding, and encapsulating adhesive curing, integrating other materials and components onto it. The LED reflector bracket needs to reflect the light emitted by the LED chip at a specific angle to reduce light loss, and then, through encapsulation materials such as epoxy resin or silicone, form the light source for LED lighting or displays. The LED reflector bracket material is a core material in LED lighting, directly affecting the performance and lifespan of the LED light source.

[0003] In LED displays, epoxy adhesives are primarily used for encapsulation. The adhesion between the epoxy adhesive and the reflector material directly affects the airtightness of the LED chips and the lifespan of the display. If the adhesion between the adhesive and the reflector material is poor, the adhesive can easily peel off, allowing moisture to enter the LED chips through the interface between the adhesive and the reflector material during use, causing LED failure and affecting the lifespan of the display.

[0004] Currently, over 50% of LED failures in displays are due to issues with the adhesion between the adhesive and the bracket material. Therefore, the bonding strength between the adhesive and the bracket plastic material is a crucial performance characteristic.

[0005] To improve the airtightness of LED chips and reduce dead LEDs in displays, while also enhancing display cleanliness and electrostatic safety during the encapsulation process, LED reflector brackets used in outdoor lighting and displays require enhanced adhesion between the bracket plastic and the encapsulation adhesive. Furthermore, the LED reflector bracket material must possess permanent antistatic properties, maintain high initial reflectivity, and resist yellowing. Simultaneously, the LED reflector bracket molding mold is a high-cavity (over 2000 cavities per mold) rapid molding process (within 15 seconds), necessitating careful attention to the molding efficiency of the LED reflector bracket material. Summary of the Invention

[0006] The purpose of this invention is to overcome the above-mentioned technical defects and provide a product with advantages such as high light reflectivity, strong adhesion to epoxy adhesive, and rapid molding, as well as its preparation method and application.

[0007] A semi-aromatic polyamide composition, comprising, by weight, the following components:

[0008] PA10T / X 40-75 parts;

[0009] 5-15 parts of polyamide elastomer;

[0010] 15-40 parts of white filler;

[0011] 5-20 parts of reinforcing filler;

[0012] 0.5-2.5 parts of hydroxide metal salt;

[0013] Wherein, PA10T / X is based on the molar percentage of PA10T / X, the content of 10T unit is 40-70 mol%, and the content of X unit is 30-60 mol%, and the X unit is not 10T; wherein, the X unit is composed of diacid unit and diamine unit, the diacid unit is selected from at least one of terephthalic acid unit, isophthalic acid unit, 1,6-adipic acid, and 1,10-sebacic 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, and 1,12-dodecanediamine unit.

[0014] Preferably, in the PA10T / X, the content of 10T unit is 50-60 mol% and the content of X unit is 40-50 mol%.

[0015] Specifically, PA10T / X can be PA10T / 10I, PA10T / 6T, PA10T / 66, PA10T / 1010, PA10T / 610, PA10T / 612, PA10T / 12T, etc.

[0016] 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.; and the content of white filler can be 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, etc., for reinforcement. The content of the 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 hydroxide metal 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.

[0017] The PA10T / X resin of the present invention can be a commercially available product or can be synthesized in-house. Those skilled in the art can conventionally select a synthesis method for PA10T / X resin. The synthesis methods for PA10T / X resin include, but are not limited to, the following methods:

[0018] (1) Prepolymerization: In a stainless steel high-pressure reactor equipped with mechanical stirring, add the polymerization monomers (diacid, diamine), end-capping agent (benzoic acid), and deionized water. After evacuating the reactor and purging with N2 three times, start heating and stirring at a rate of 4-6℃ / min to 170-190℃. Hold the temperature for 1-2 hours, then heat at a rate of 1-3℃ / min to 260-280℃, stirring slowly and holding the temperature for 3-5 hours to allow the prepolymerization reaction to proceed fully. After the temperature is held, slowly increase the temperature to 270-290℃ and begin draining the water to atmospheric pressure. Once the pressure drops to atmospheric pressure, close the drain valve; the reaction is complete. Discharge the material at room temperature.

[0019] (2) Solid-phase viscosity enhancement: The material prepared in the prepolymerization process is put into a vacuum drum. The drum speed is set to 10-15 r / min and the vacuum degree is set to 25-35 Pa. The temperature is increased at a rate of 15-25℃ / min. When the temperature reaches 260-270℃, a sample is taken to test the viscosity. The discharge endpoint is determined based on the viscosity (or number average molecular weight) result.

[0020] The number-average molecular weight (Mn) of the PA10T / X resin is 2000~25000. The number-average molecular weight was determined using a conventional method: the number-average molecular weight (Mn) of the PA10T / X resin sample was determined by gel permeation chromatography (GPC). An Agilent HPLC-1260 high-performance liquid chromatograph was used, equipped with an Eppendorf column oven, Shodex KF-801, 802, 802.5, and 803 gel permeation columns, a differential detector, and a G7129A autosampler. Hexafluoroisopropanol was used as the mobile phase, and the molecular weight of the resin was determined at a column temperature of 40℃. The data was processed using the CIRRUS software on a chromatography workstation to obtain the number-average molecular weight distribution (Mn).

[0021] The semi-aromatic polyamide composition was measured by differential scanning calorimetry (DSC) under a nitrogen atmosphere. The temperature was increased from 30°C to 350°C at a rate of 20°C / min and held at that temperature for 2 min. The half-width at half-maximum (HWHM) of the crystallization peak was 4-16°C.

[0022] Optionally, the crystallization peak half-width ΔT1 / 2 of PA10T / X resin is 4-16℃.

[0023] The polyamide elastomer is selected from at least one of polyester-type polyamide elastomers and polyether-type polyamide elastomers. The hard segment of the polyamide elastomer can be PA1012, PA11, PA12, PA1010, PA1212, PA1213, PA612, PA6, etc.

[0024] 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 micrometers.

[0025] The reinforcing filler is selected from at least one of wollastonite, potassium titanate, kaolin, and talc, with potassium titanate being preferred.

[0026] The average particle size of the wollastonite, potassium titanate, kaolin, and talc is 0.1-15 micrometers.

[0027] The average particle size was measured using a laser particle size analyzer.

[0028] The hydroxide metal salt is selected from group IA, IIA, and IIIA metal hydroxides, preferably at least one of magnesium hydroxide, calcium hydroxide, aluminum hydroxide, and sodium hydroxide, and the average particle size of the hydroxide metal salt is 0.1-15 micrometers. Magnesium hydroxide is preferred. In one embodiment, the hydroxide metal salt accounts for 0.3-3.7 wt% of the total weight of the semi-aromatic polyamide composition.

[0029] Depending on the actual situation, it may be optional to add 0-2 parts of an additive, which is selected from at least one of antioxidants, lubricants, and UV resistant agents.

[0030] 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 them evenly, and then extruding and granulating them through a twin-screw extruder to obtain the semi-aromatic polyamide composition; wherein the screw temperature range is 280-330℃ and the rotation speed is 400-500r / min.

[0031] An LED reflector bracket prepared from the semi-aromatic polyamide composition of the present invention.

[0032] An LED light source includes an LED reflector bracket prepared from the semi-aromatic polyamide composition of the present invention, wherein the LED reflector bracket is encapsulated with epoxy resin adhesive and is formed by multi-cavity processing.

[0033] The present invention has the following beneficial effects:

[0034] This invention enhances the bonding strength between the polyamide elastomer and epoxy adhesive through their interaction. The acid-absorbing effect of the hydroxyl metal salt not only significantly improves the initial light reflectivity, but also, as an alkaline substance, it reacts with the epoxy groups in the epoxy resin, promoting the curing process. During the curing reaction, the hydroxyl metal salt lowers the activation energy and increases the reaction rate, thereby accelerating the curing process, improving the curing efficiency of the epoxy resin, and further enhancing the bonding strength between the composition and the epoxy adhesive. Furthermore, the semi-aromatic polyamide composition of this invention exhibits rapid prototyping properties, making it suitable for multi-cavity rapid prototyping. This makes the semi-aromatic polyamide composition of this invention suitable for preparing LED reflector brackets. Attached Figure Description

[0035] Figure 1: Dimensions of the sample during the adhesive bonding strength test. Detailed Implementation

[0036] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0037] The raw materials used in the embodiments and comparative examples of this invention are as follows:

[0038] 10T unit content, mol% number-average molecular weight ΔT 1 / 2 , ℃PA10T / 10I-14091004.5PA10T / 10I-250890012.0PA10T / 10I-360830015PA10T / 10I-470950 013.0PA10T / 10I-53094003.8PA10T / 10I-6801050017.1PA10T / 1010-14098004.3PA10T / 1010 -250103007.6PA10T / 1010-3601080011.9PA10T / 1010-470960013.2PA10T / 1010-53088003.7 PA10T / 1010-680750015.1PA10T / 6T601360010.3PA10T / 6125064008.2PA10T / 61055227009.4

[0039] The polyamide resin mentioned above is a self-made raw material.

[0040] Polyamide elastomer A: The polyamide hard segment is PA12, Arkema Pebax® 4533 (France);

[0041] Polyamide elastomer B: The polyamide hard segment is PA12, Wanhua Chemical WHE-4011;

[0042] Polyamide elastomer C: The polyamide hard segment is PA11, Pebax® Rnew 25R53 SP 01, Arkema, France;

[0043] Polyamide elastomer D: The polyamide hard segment is PA6, AS5505, Beijing Xuyang Technology;

[0044] The titanium dioxide was purchased from Longbai and the required average particle size was obtained through screening.

[0045] Titanium dioxide A: Average particle size 0.11 micrometers;

[0046] Titanium dioxide B: Average particle size 0.50 micrometers;

[0047] Zinc sulfide: Sachtolith HD-S, average particle size 0.14 micrometers, purchased from Sachtolith, Germany;

[0048] Wollastonite: average particle size is 12 micrometers;

[0049] Potassium titanate: Nantong Aoxin Electronics Co., Ltd., average particle size 3-5μm;

[0050] Kaolin: Forsmann Technology (Beijing) Co., Ltd., average particle size 0.3μm;

[0051] Magnesium hydroxide: Hefei Zhongke Flame Retardant New Materials Co., Ltd., with an average particle size of 0.4-2μm;

[0052] Calcium hydroxide: Jiangxi Chuangxian Fine Calcium Industry Co., Ltd., average particle size 10μm;

[0053] Aluminum hydroxide: China Aluminum H-WF-10, average particle size 0.8μm.

[0054] Preparation method of semi-aromatic polyamide composition in examples and comparative examples: Each component is added to a mixer and mixed evenly, and then extruded and granulated by a twin-screw extruder to obtain a semi-aromatic polyamide composition; wherein the screw temperature range is 280-330℃ and the speed is 450r / min.

[0055] Test methods:

[0056] (1) Half-maximum width at half maximum (FWHM) of the crystallization peak of the semi-aromatic polyamide composition ΔT 1 / 2Using a differential scanning calorimeter manufactured by NETZSCH, the temperature was increased from 30°C to 345°C at a rate of 20°C / min under a nitrogen atmosphere. After holding at this temperature for 2 min, the temperature was decreased at a rate of 20°C / min. The temperature at which the crystallization peak appeared was set as the crystallization temperature Tc (°C), and the temperature at which the peak width was half the measured value was set as the half-width at half-maximum (WHM) ΔT. 1 / 2 .

[0057] (2) Reflectance: A test piece with a length of 60 mm, a width of 60 mm, and a thickness of 1 mm was prepared by injection molding of a semi-aromatic polyamide composition. The reflectance of the test piece to light with a wavelength of 460 nm was measured using a Color Eye 7000A colorimeter.

[0058] (3) Adhesive bonding strength test: The plastic is injection molded into a sample with the dimensions shown in the attached diagram of the instruction manual. Then, epoxy adhesive is poured into the grooves of the two strips, clamped with clips, baked at 150℃ for 8 hours, cooled for more than 4 hours, and then the adhesive strips are broken at the joint by a universal testing machine to measure the adhesive bonding shear stress, in MPa.

[0059] Table 1: Partial proportions (by weight) and test results of the semi-aromatic polyamide compositions in Examples 1-7

[0060] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 PA10T / 10I-140607560606060 Polyamide elastomer A5101510 Polyamide elastomer B10 Polyamide elastomer C10 Polyamide elastomer D10 Titanium dioxide A153040303030 Titanium dioxide B30 Wollastonite 5102010101010 Magnesium hydroxide 0.51.52.51.51.51.51.5 Crystallization peak half-width ΔT 1 / 2 ,℃ 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 Adhesive Bonding Strength 30.0 35.3 38.5 35.8 33.8 34.2 36.6

[0061] As can be seen from Examples 2 / 4-6, polyester-type polyamide elastomers are preferred.

[0062] Table 2: Partial proportions (by weight) and test results of the semi-aromatic polyamide compositions in Examples 7-11

[0063] Example 7 Example 8 Example 9 Example 10 Example 11 PA10T / 10I-16060606060 Polyamide elastomer A1010101010 Titanium dioxide A30303030 Zinc sulfide 30 Wollastonite 101010 Potassium titanate 10 Kaolin 10 Magnesium hydroxide 1.5 1.5 1.5 Calcium hydroxide 1.5 Aluminum hydroxide 1.5 Crystallization peak half-width ΔT 1 / 2 ,℃ 6.2 5.4 5.9 6.2 5.6 460nm Reflectivity, % 91.6 94.1 92.5 93.5 93.2 Adhesive Bonding Strength 39.1 40.6 36.5 31 33

[0064] As can be seen from Examples 2 / 7, the white filler selected from zinc sulfide has better bonding strength with the adhesive.

[0065] As can be seen from Examples 2 / 8-9, potassium titanate is preferred as the reinforcing filler, resulting in better reflectivity and adhesive strength.

[0066] As can be seen from Examples 2 / 10 / 11, magnesium hydroxide is the preferred hydroxide metal salt.

[0067] Table 3: Parts by weight and test results of the semi-aromatic polyamide compositions in Examples 12-18

[0068] Example 12 Example 13 Example 14 Example 15 Example 16 Example 17 Example 18 PA10T / 10I-260 PA10T / 10I-360 PA10T / 10I-460 PA10T / 1010-160 PA10T / 1010-260 PA10T / 1010-360 PA10T / 1010-460 Polyamide elastomer A10101010101010 Titanium dioxide A30303030303030 Wollastonite 10101010101010 Magnesium hydroxide 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Crystallization peak half-width ΔT 1 / 2 ,℃ 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 Adhesive Bonding Strength 37.9 38.4 37.1 36.9 38.4 37.5 36.9

[0069] As can be seen from Examples 2 / 12-13 and Examples 15-18, when the content of 10T unit is 50-60 mol% and the content of X unit is 40-50 mol%, the adhesion to the adhesive is stronger and the light reflectivity is significantly higher.

[0070] Table 4: Partial proportions (by weight) and test results of the semi-aromatic polyamide compositions in Examples 19-21

[0071] Example 19 Example 20 Example 21 PA10T / 6T60 PA10T / 61260 PA10T / 61060 Polyamide elastomer A101010 Titanium dioxide A303030 Wollastonite 101010 Magnesium hydroxide 1.5 1.5 1.5 Crystallization peak half-width ΔT 1 / 2 ,℃ 10.8 8.9 9.8 460nm Reflectivity, % 93.6 94.1 93.6 Adhesive Bonding Strength 37.1 36.5 35.9

[0072] Table 5: Partial proportions (by weight) and test results of the semi-aromatic polyamide compositions in Comparative Examples 1-4

[0073] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 PA10T / 10I-560 PA10T / 10I-660 PA10T / 1010-560 PA10T / 1010-660 Polyamide Elastomer A10101010 Titanium Dioxide A30303030 Wollastonite 10101010 Magnesium Hydroxide 1.5 1.5 1.5 1.5 Crystallization Peak Half-Width ΔT 1 / 2 ℃ 3.9 19.2 3.6 16.1 460nm Reflectivity, % 90.6 91.1 91.0 91.5 Adhesive strength 23 25 28 21

[0074] As can be seen from Comparative Examples 1-4, when the polyamide repeating unit is not within the scope of the present invention, the half-width at half-maximum (WHM) of the crystallization peak of the semi-aromatic polyamide composition is not within the scope of the present invention, resulting in poor adhesion to the adhesive.

[0075] Table 6: Distribution ratios (parts by weight) and test results of each group in Comparative Examples 5-7

[0076] Comparative Example 5, Comparative Example 6, Comparative Example 7: PA10T / 10I-1606060, Polyamide Elastomer A01010, Titanium Dioxide A303030, Wollastonite 101010, Magnesium Hydroxide 1.504, Crystallization Peak Full Horizon ΔT 1 / 2 ℃ 6.26.26460nm reflectance, % 938989.5% adhesive strength 153225

[0077] As shown in Comparative Example 5, the adhesion to the glue is poor when polyamide elastomer is not present.

[0078] As shown in Comparative Example 6, the light reflectance is low when magnesium hydroxide is not present.

[0079] As shown in Comparative Example 7, when the magnesium hydroxide content is too high, it will reduce the light reflectivity and the adhesion to the glue.

Claims

1. A semi-aromatic polyamide composition, characterized in that, By weight, it includes the following components: PA10T / X 40-75 parts; 5-15 parts of polyamide elastomer; 15-40 parts of white filler; 5-20 parts of reinforcing filler; 0.5-2.5 parts of hydroxide metal salt; PA10T / X, based on the molar percentage of PA10T / X, has a 10T unit content of 40-70 mol% and an X unit content of 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 being selected from at least one of terephthalic acid unit, isophthalic acid unit, 1,6-adipic acid, and 1,10-decanedioic acid unit, and the diamine unit being 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 content of 10T unit is 50-60 mol% and the content of X unit is 40-50 mol%.

3. The semi-aromatic polyamide composition according to claim 1, characterized in that, The semi-aromatic polyamide composition was measured by differential scanning calorimetry (DSC) under a nitrogen atmosphere. The temperature was increased from 30°C to 350°C at a rate of 20°C / min and held at that temperature for 2 min. The half-width at half-maximum (HWHM) of the crystallization peak was 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 micrometers.

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, with potassium titanate being preferred.

6. The semi-aromatic polyamide composition according to claim 1, characterized in that, The hydroxide metal salt is selected from metal hydroxides of Group 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 micrometers.

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

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

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

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

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